hig.sePublications
Change search
Refine search result
10111213141516 601 - 650 of 821
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • harvard-cite-them-right
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • sv-SE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • de-DE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Rows per page
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sort
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
Select
The maximal number of hits you can export is 250. When you want to export more records please use the Create feeds function.
  • 601.
    Richter, Hans
    et al.
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, Occupational health science. University of Gävle, Centre for Musculoskeletal Research.
    Domkin, Dmitry
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, Occupational health science. University of Gävle, Centre for Musculoskeletal Research.
    Elcadi, Guilherme H.
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, Occupational health science. University of Gävle, Centre for Musculoskeletal Research.
    Andersson, Helena
    Skogforsk, the forestry research institute of Sweden, Uppsala, Sweden.
    Högberg, Hans
    University of Gävle, Faculty of Health and Occupational Studies, Department of Health and Caring Sciences, Caring science.
    Forsman, Mikael
    Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden.
    Englund, Martin
    Skogforsk, the forestry research institute of Sweden, Uppsala, Sweden.
    A comparsion of mental and visual loads resulting from semi-automated and conventional forest harvesting: An experimental machine simulation study2018In: FALF Konferens 2018: Arbetet - problem eller potential för en hållbar livsmiljö?: Program och Abstracts / [ed] Per Lindberg, Gävle: Gävle Universtiy Press , 2018, p. 96-Conference paper (Other academic)
    Abstract [en]

    This study is concerned with a new method for partly automating forestry harvesting work. Work-related injuries and constant demands for a higher productivity are two of the many arguments for why forestry work must be improved. Forestry work places great mental demands on the driver because they must continuously evaluate and act on relevant parts in a heavy visual information flow. Against this background the purpose of the present study was to extend the knowledge of functional linkages between visual and mental fatigue, performance, and prefrontal cortex activity, during semi-automated and conventional forestry harvesting work. Eleven healthy participants, range 21–51 years old, with a minimum of 1-year work experience, carried out the task of loading logs along a standardized path in a machine simulator during two counterbalanced 45-min periods: (i) conventional forest harvesting, and; (ii) semi-automated forest harvesting. Equal emphasizes was put on accuracy and speed. During manual forest harvesting the driver controlled the crane arm, used to load logs into the load space of the forest vehicle (“forwarder”), by manually operating the joysticks and so guide the crane to the location of the log and then back to the load space. During semi-automatic forest harvesting the driver moved the crane with the press of a button to a pre-programmed location near the log and then, after another button press, to a pre-programmed location within the load space. The following joystick usage parameters were considered for the statistical analysis: Sequential work cycle number, work phase (1-loading in basket, 2-movement to log, 3-picking up log, 4-movement to load space), number of simultaneously used controls across samples of one phase, number of direction changes of joystick movements per phase. Mental load was assessed by quantification of oxygenated hemoglobin (HbO2) concentration changes over the right dorsolateral prefrontal cortex (dlPFC) via non-invasive functional near infrared spectrometry (fFNIRS: PortaLite mini, Artinis Medical Systems, Zetten, the Netherlands). The frequency and duration of horizontal amplitudes of eye/head/neck angles was assessed continuously with 8 SmartEye cameras and used as a measure of visual load. NASA-TLX and Borg CRS was used to assess perceived mental and physical fatigue. Linear Mixed Model will be used to test and to analyze the effect of the duration of work, joystick usage, work type (manual or semi-automated) and perceived mental and physical effort on the outcome of oxygenated hemoglobin concentration. This study contributes with new knowledge of the consequences of the current increase in automation. The 4th industrial revolution can have tremendous implications on how we perceive and organize work in the future, but little is still known about the impact on human body and brain.

  • 602.
    Richter, Hans
    et al.
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, Occupational health science. University of Gävle, Centre for Musculoskeletal Research.
    Domkin, Dmitry
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, Occupational health science. University of Gävle, Centre for Musculoskeletal Research.
    Forsman, Mikael
    Division of Occupational and Environmental Medicine, Department of Public Health Sciences, Karolinska Institute.
    Ciliary muscle contraction force and trapezius muscle activity during manual tracking of visual targets2014In: The Association for Research in Vision and Ophthalmology Annual Meeting: ARVO 2014, 2014, p. 263-Conference paper (Refereed)
  • 603.
    Richter, Hans
    et al.
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, Occupational health science. University of Gävle, Centre for Musculoskeletal Research.
    Forsman, Mikael
    Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden.
    Elcadi, Guilherme H.
    University of Gävle, Faculty of Health and Occupational Studies, Department of Health and Caring Sciences, Sports science.
    Brautaset, R.
    School of Optometry, Karolinska Institutet, Stockholm, Sweden.
    Marsh, John E.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building, Energy and Environmental Engineering, Environmental psychology. School of Psychology, University of Central Lancashire, Preston, United Kingdom.
    Zetterberg, Camilla
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, Occupational health science. University of Gävle, Centre for Musculoskeletal Research. Section of Occupational and Environmental Medicine, Department of Medical Sciences, Uppsala University, Uppsala, Sweden.
    Prefrontal cortex activity evoked by convergence load under conflicting stimulus-to-accommodation and stimulus-to-vergence eye-movements measured by NIRS: Prefrontal cortex oxygenation and visual fatigue2018In: Frontiers in Human Neuroscience, ISSN 1662-5161, E-ISSN 1662-5161, Vol. 12, article id 298Article in journal (Refereed)
    Abstract [en]

    Purpose: To extend our knowledge of the functional linkages between visual fatigueand regional cerebral prefrontal cortex (PFC) oxygenation, we measured time related hemodynamic changes over the right dorsolateral prefrontal cortex (dlPFC) duringconvergence load under conflicting stimulus-to-accommodation and stimulus-tovergence eye movements with and without concurrent mental load.

    Methods: Twenty healthy participants with a median age of 28 years (range:18–44 years) fixated upon a vertical bar presented separately to the left andright eyes, using polarized filters, during four counterbalanced 10-min periods:(i) no accommodation/vergence conflict (Control, Ctrl); (ii) added convergenceload and accommodation/vergence conflict (Conv); (iii) added cognitive load only(Cog) and; (iv) a combination of added cognitive and convergence load andaccommodation/vergence conflict (Cc). Viewing distance was 65 cm. Non-invasivemeasurements of hemodynamic activity over the dlPFC were quantified by functionalnear-infrared spectroscopy (fNIRS). During the two-convergence load conditions, thehorizontal disparity of the two bars varied dynamically from no disparity to a disparityset 20% below the individual threshold for diplopia. Cognitive load was induced by then-back-2 test which required the subject to memorize and recall the changing colorsof the horizontal bars and decide when a given color was the same as that occurring two colors previously. fNIRS data were averaged over 10-s windows centered at 0, 2,4, 6, 8, and 10 min of each task, subtracted from a 20-s baseline window immediatelypreceding the visual task, and then represented as changes in oxygenated hemoglobin(ΔHbO2); deoxygenated hemoglobin (ΔHHb) and total hemoglobin (ΔtHb).

    Results: Linear mixed model analyses showed that hemodynamic activity wassystematically influenced by time (p < 0.001). The group-averaged time-related levelof change across the viewing conditions did not differ when compared with one another(p > 0.05). Larger convergence eye-movement responses under conflicting stimulus-to accommodation,and stimulus-to-vergence over time, increased ΔHbO2 and ΔtHb onlyin condition Cc and after 8 min of task time (p < 0.10 for min-6 and min-8: p < 0.05 for min-10).

    Discussion: Collectively, our data suggest that HbO2, HHb, and tHb, recorded over the dlPFC with fNIRS, can be used to assay the degree to which supervisory oculomotorcontrol processes are activated during visually deficient near work.

    Download full text (pdf)
    fulltext
    Download full text (pdf)
    corrigendum
  • 604.
    Richter, Hans
    et al.
    University of Gävle, Centre for Musculoskeletal Research.
    Lodin, Camilla
    University of Gävle, Centre for Musculoskeletal Research.
    Why eye strain can be pain in the neck2008Conference paper (Refereed)
  • 605.
    Richter, Hans
    et al.
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, CBF. University of Gävle, Centre for Musculoskeletal Research.
    Lodin, Camilla
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, CBF. University of Gävle, Centre for Musculoskeletal Research.
    Forsman, Mikael
    Karolinska institutet.
    Temporal aspects of increases in eye-neck activation levels during visually deficient near work2012In: Work: A journal of Prevention, Assessment and rehabilitation, ISSN 1051-9815, E-ISSN 1875-9270, Vol. 41, no Suppl. 1, p. 3379-3384Article in journal (Refereed)
    Abstract [en]

    In an experimental study two levels of oculomotor load were induced via optical trial lenses. Trapezius muscle activity was measured with bipolar surface electromyography and normalized to a submaximal contraction. Sixty-six subjects with a median age of 36 (range 19–47, std 8) viewed a black and white Gabor grating (5 c/deg) for two 7-min periods monocularly through a 0 D lens or binocularly through -3.5 D lenses. The effect of time was separately regressed to EMG in two different subgroups of responders: a High-Oculomotor-Load (HOL) and a Low-Oculomotor-Load (LOL) group. A linear regression model was fitted on group level with exposure time on the x-axis and normalized trapezius muscle EMG (%RVE) on the y-axis. The slope coefficient was significantly positive in the -D blur condition for only the HOL subgroup of responders: 0.926 + Time min 1-7x 0.088 (p = 0.002, r2 =0.865). There was no obvious sign of this activity to level off or to stabilize. These results suggest that professional information technology users that are exposed to a high level of oculomotor load, during extended times, are at an increased risk of exhibiting an increased trap.m. activity.

  • 606.
    Richter, Hans
    et al.
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational Health Science and Psychology, Occupational Health Science. University of Gävle, Centre for Musculoskeletal Research.
    Long, Jennifer
    School of Optometry and Vision Science, UNSW Sydney, Sydney, AUSTRALIA.
    The pitfalls of the traditional office ergonomics model in the current mobile work environment:  Is visual ergonomic health literacy the remedy?2019In: Work: A journal of Prevention, Assessment and rehabilitation, ISSN 1051-9815, E-ISSN 1875-9270, Vol. 63, no 3, p. 447-456Article in journal (Refereed)
    Abstract [en]

    Mobile technology has revolutionised how we work. It is now relatively easy to work anywhere and anytime, but this has placed the onus on mobile (or flexible) workers to set up their own work environment for comfort and ease of use. Vision is an important driver of posture, and hence visual ergonomics principles are integral for setting up digital devices. If mobile workers do not have visual ergonomics knowledge, or are unable to apply visual ergonomics knowledge to appropriately set up their work environment, then they are at risk of developing visual-related occupational health issues due to exposure to adverse physical work environments.

    To address this potential health care issue, we propose the introduction of Visual Ergonomics Health Literacy. This would provide mobile workers (including school children) with the knowledge and skills to set up their work environment for comfort and ease of use, wherever they work. It is important to address this issue now before we have a widespread epidemic of discomfort and injury from not applying sound visual ergonomics principles to work environments.

  • 607.
    Richter, Hans O
    University of Gävle, Centre for Musculoskeletal Research.
    Accommodative/vergence performance following low-levels sustained oculomotor load2007In: 30th European Conference on Visual Perception: Perception 36 Suppl., 2007, p. 30-Conference paper (Other academic)
  • 608.
    Richter, Hans O
    University of Gävle, Centre for Musculoskeletal Research.
    Eye-neck/scapular area interactions during strenuous near work: biologically plausible pathways with relevance for work related musculoskeletal disorders of the neck and upper extremity2008In: Zeitschrift für Arbeitswissenschaft, ISSN 0340-2444, Vol. 3, no 62, p. 190-199Article in journal (Refereed)
    Abstract [en]

    The time honoured dictum “the eyes steer the body” has gained additional legitimacy in recent years with the advent of new mechanisms which link the visual and musculoskeletal system with one another. A systematic review of the circumstances, under which a change in accommodation/vergence loads actually lead to alterations in physiological levels of musculoskeletal tonus, or vice versa, therefore, appears timely.

  • 609.
    Richter, Hans O
    University of Gävle, Centre for Musculoskeletal Research.
    Neck shoulder activation induced by deficient visual quality2007In: 39th Annual Congress of the Nordic Ergonomics Society, 2007Conference paper (Other academic)
  • 610.
    Richter, Hans O.
    et al.
    University of Gävle, Centre for Musculoskeletal Research.
    Bänziger, Tanja
    Abdi, S.
    Forsman, Mikael
    Low-level sustained accommodative/vergence loads, eyestrain and trapezius muscle activity2008In: Perception, ISSN 0301-0066, E-ISSN 1468-4233, Vol. 37, no Suppl., p. 24-24Article in journal (Refereed)
  • 611.
    Richter, Hans O.
    et al.
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, CBF. University of Gävle, Centre for Musculoskeletal Research.
    Bänziger, Tanja
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, CBF. University of Gävle, Centre for Musculoskeletal Research.
    Abdi, S.
    The Bernadotte Laboratories, St. Erik’s Eye Hospital, Department of Clinical Neuroscience, Karolinska Institutet, Sweden.
    Forsman, Mikael
    Division of Occupational and Environmental Medicine, Department of Public Health Sciences, Karolinska Institutet, Sweden.
    Stabilization of gaze: A relationship between ciliary muscle contraction and trapezius muscle activity2010In: Vision Research, ISSN 0042-6989, E-ISSN 1878-5646, Vol. 50, no 23, p. 2559-2569Article in journal (Refereed)
    Abstract [en]

    In an experimental study four levels of oculomotor load were induced binocularly. Trapezius muscle activity was measured with bipolar surface electromyography and normalized to a submaximal contraction. Twenty-eight subjects with a mean age of 29 (range 19–42, std 8) viewed a high-contrast fixationt arget for four 5-min periods through: (i) 3.5 dioptre (D) lenses; (ii) 0 D lenses; (iii) individuallya djusted prism D lenses (1–2 D base out); and (iv) +3.5 D lenses. The target was placed close to thei ndividual’s age-appropriate near point of accommodation in conditions (i–iii) and at 3 m in condition( iv). Each subject’s ability to compensate for the added blur was extracted via infrared photorefraction measurements. A bitwise linear regression model was fitted on group level with eye-lens refraction on the x-axis and normalized trapezius muscle EMG (%RVE) on the y -axis. The model had a constant level of trapezius muscle activity – where subjects had not compensated for the incurred defocus by a change in eye-lens accommodation – and a slope, where the subjects had compensated. The slope coefficient was significantly positive in the D (i) and the +D blur conditions (iv). During no blur (ii) and prism blur (iii) there were no signs of relationships. Nor was there any sign of relationship between the convergence response and trapezius muscle EMG in any of the experimental conditions. The results appear directly attributable to an engagement of the eye-lens accommodative system and most likely reflect sensorimotor processing along its reflex arc for the purpose of achieving stabilization of gaze

  • 612.
    Richter, Hans O.
    et al.
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, CBF. University of Gävle, Centre for Musculoskeletal Research.
    Bänziger, Tanja
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, CBF. University of Gävle, Centre for Musculoskeletal Research.
    Forsman, Mikael
    Division of Occupational and Environmental Medicine, Department of Public Health Sciences, Karolinska Institutet, Sweden.
    Eye-lens accommodation load and static trapezius muscle activity2011In: European Journal of Applied Physiology, ISSN 1439-6319, E-ISSN 1439-6327, Vol. 111, no 1, p. 29-36Article in journal (Refereed)
    Abstract [en]

    The purpose of this experimental study was to investigate if sustained periods of oculomotor load impacts on neck/scapular area muscle activity. The static trapezius muscle activity was assessed from bipolar surface electromyography, normalized to a submaximal contraction. Twenty-eight subjects with a mean age of 29 (range 19–42, SD 8) viewed a high-contrast fixation target for two 5-min periods through: (1) -3.5 dioptre (D) lenses; and (2) 0 D lenses. The target was placed 5 D away from the individual’s near point of accommodation. Each subject’s ability to compensate for the added blur was extracted via infrared photorefraction measurements. Subjects whose accommodative response was higher in the -D blur condition (1) showed relatively more static bilateral trapezius muscle activity level. During no blur (2) there were no signs of relationships. The results indicate that sustained eye-lens accommodation at near, during ergonomically unfavourable viewing conditions, could possibly represent a risk factor for trapezius muscle myalgia.

  • 613.
    Richter, Hans O
    et al.
    University of Gävle, Centre for Musculoskeletal Research.
    Crenshaw, Albert
    University of Gävle, Centre for Musculoskeletal Research.
    Djupsjöbacka, Mats
    University of Gävle, Centre for Musculoskeletal Research.
    Kjellberg, Anders
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för inomhusmiljö.
    Lyskov, Eugene
    University of Gävle, Centre for Musculoskeletal Research.
    Accommodative/vergence eye-movements in response to optical blur and musculoskeletal discomfort2007In: Work with computing systems - WWCS 2007, Stockholm: Computing systems for human benefits from the 8th International Conference on Work With Computing Systems : May 21st-24th 2007, Stockholm Sweden, Stockholm: Royal institute of technology , 2007, p. 125-125Conference paper (Refereed)
  • 614.
    Richter, Hans O
    et al.
    University of Gävle, Centre for Musculoskeletal Research.
    Crenshaw, Albert
    University of Gävle, Centre for Musculoskeletal Research.
    Lyskov, Eugene
    University of Gävle, Centre for Musculoskeletal Research.
    Accommodation – vergence performance after low levels of oculomotor load2007In: Scandinavian Journal of Work, Environment and Health, ISSN 0355-3140, E-ISSN 1795-990X, no 3, p. 60-67Article in journal (Refereed)
    Abstract [en]

    Objectives This experimental pilot study assessed the effects of sustained low-level accommodative vergence loads on oculomotor performance, eyestrain, and musculoskeletal functioning.

    Methods A high-contrast fixation-point stimulus [light-emitting diode (LED)] was introduced into the optical axis of the viewing eye or into the midline in case of binocular viewing. The participants (N=6) were asked to compensate for the blur incurred by adjusting the strength of their eye lens. The participants performed in the following three standardized sequential viewing tasks: (i) resting with eyes open in darkness, (ii) accommodating alternately on a near versus a far LED illuminated sequentially (near–far response), and (iii) sustained fixation upon a LED at near. After the third task, the first and second tasks were repeated once.

    Results The main effects of the third task were to decrease the overall rate of binocular accommodative relaxation time (diopters/s) in the repetition of the second task trial. The baseline shifts in individual response times also correlated with changes in the response amplitudes under the binocular stimulus conditions, which required contraction of the ciliary muscle.

    Conclusions The results taken as a whole validate a technique of essential interest to applied vision research.

  • 615.
    Richter, Hans O
    et al.
    University of Gävle, Centre for Musculoskeletal Research.
    Crenshaw, Albert
    University of Gävle, Centre for Musculoskeletal Research.
    Lyskov, Eugene
    University of Gävle, Centre for Musculoskeletal Research.
    Low-levels sustained accommodative/vergence loads, eyestrain and neck-shoulder discomfort2007In: Work With Display Unit, 2007Conference paper (Other academic)
  • 616.
    Richter, Hans O
    et al.
    University of Gävle, Centre for Musculoskeletal Research.
    Elfström, A
    Kjellberg, Anders
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för inomhusmiljö.
    Zetterström,
    Wiholm, Clairy
    Visual stress a risk factor for musculo-skeletal complaints in visual display unit workers2007In: Work With Display Unit, 2007Conference paper (Other (popular science, discussion, etc.))
  • 617.
    Richter, Hans O
    et al.
    University of Gävle, Centre for Musculoskeletal Research.
    Knez, Igor
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för inomhusmiljö.
    Superior low-wavelength contrast sensitivity in asthenopics during voluntary efforts to accommodation2006In: 29th European Conference on Visual Perception: Perception 35. Suppl, 2006, p. 131-131Conference paper (Other academic)
    Abstract [en]

    The purpose of this work was to characterise short-(S)-wavelength-sensitive-cone mediated contrast sensitivity (CS) across twenty symptom-free subjects and eight asthenopics, all with normal-unaided-or-corrected visual acuity with no sign of oculomotor dysfunction. Threshold contrast sensitivity was assessed by the von Békésy tracking method from a viewing distance of 2.4 m (0.40 D). Three counterbalanced tasks required central fixation of black-and-white square-wave gratings (1, 5, 10, 14, and 17 cycles deg-1) presented through a low-pass (400 - 450 nm) tinted blue lens: through (i) a 0.0 D lens, (ii) a -1.50 D lens, (iii) a +1.50 D lens while attempting volitional accommodation to minimise blur. Baseline increases in eye-strain, which approached high levels at the end of the experiment, did not differentiate between the two groups of volunteers. Compared with symptom-free subjects, asthenopics exhibited larger magnitudes CS performance in the intermediate spatial frequencies during experimental conditions requiring voluntary increases in accommodation. The residual filtered light may encompass reference wavelengths habitually used by the asthenopics in retinal alignment as an adaptive strategy to spare accommodation from eye-strain. Alternatively, asthenopics, owing to inherent retinal factors, may 'drive' their accommodative system harder than symptom-free subjects.[Supported by the Swedish Council for Working Life and Social Research Grant 2005-0488 to HR.]

  • 618.
    Richter, Hans O.
    et al.
    University of Gävle, Centre for Musculoskeletal Research. University of Gävle, Department of Education and Psychology, Ämnesavdelningen för psykologi.
    Knez, Igor
    University of Gävle, Department of Technology and Built Environment, Ämnesavdelningen för inomhusmiljö.
    Superior short-wavelength contrast sensitivity in asthenopics during reflexive readjustments of ocular accommodation2007In: Ophthalmic & physiological optics, ISSN 0275-5408, E-ISSN 1475-1313, Vol. 27, no 4, p. 361-372Article in journal (Refereed)
    Abstract [en]

    The purpose of this work was to characterize contrast sensitivity (CS) under short-wavelength illumination in 20 symptom-free subjects and eight asthenopics: all had normal unaided or corrected visual acuity and no sign of oculomotor disease. Threshold CS was assessed using the von Bekesy tracking method from a viewing distance of 2.4 m (0.40 D). Three counterbalanced tasks required central fixation of black-and-white square-wave gratings (1, 5, 10, 14 and 17 c/deg) presented through a low-pass filter blue lens and (1) a +1.50 D lens; (2) a -1.50 D lens and (3) a 0 D lens, while attempting accommodation to minimize blur. Baseline increases in eye strain, which approached high levels at the end of the experiment, did not differentiate between the two groups of volunteers. All the subjects made evident appropriate accommodation during the low blur condition (0 D); the CS curve exhibited the expected characteristics. When the minus lens was placed before the eyes of the observers the distant square-wave gratings were still seen clearly, the eyes presumably had accommodated by an amount equal to the power of the negative lens. Compared with symptom-free subjects, asthenopics exhibited greater CS at the intermediate spatial frequencies both during the low blur and the minus blur conditions. Asthenopics may exhibit an individualized sensory tendency to react more strongly to shorter wavelengths of light and may therefore reflexively 'drive' their accommodative system harder than symptom-free subjects. This would explain the presence of their asthenopia in the first place. Blue light may, in addition, induce more arousal and higher alertness in this category of participants. This would boost the oculomotor aspects of their performance. These findings add to the current understanding of individual variability in the level of oculomotor loads following strenuous near work.

  • 619.
    Richter, Hans O.
    et al.
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, CBF. University of Gävle, Centre for Musculoskeletal Research.
    Röijezon, Ulrik
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, CBF. University of Gävle, Centre for Musculoskeletal Research.
    Björklund, Martin
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, CBF. University of Gävle, Centre for Musculoskeletal Research.
    Djupsjöbacka, Mats
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, CBF. University of Gävle, Centre for Musculoskeletal Research.
    Long-term adaptation to neck/shoulder pain and perceptual performance in a hand laterality motor imagery test2010In: Perception, ISSN 0301-0066, E-ISSN 1468-4233, Vol. 39, no 1, p. 119-130Article in journal (Refereed)
    Abstract [en]

    The effect of neck/shoulder pain on the performance in a hand laterality motor imagery test was studied. Responses to the Cooper and Shepard (1975, Journal of Experimental Psychology: Human Perception and Performance 104 48 ^ 56) hand laterality test were explored in twenty-four individuals with chronic non-specific neck pain and twenty-one subjects with chronic neck pain of traumatic origin (whiplash-associated disorder). Twenty-two controls were also included in the study. Digitalised right- or left-hand stimuli were presented at five different stimulus angles (08, 458 laterally, 908 laterally, 1358 laterally, and 1808). The experimental task was to decide the laterality as fast and accurately as possible. The performance, both reaction time (RT) and accuracy, of the two experimental groups was contrasted with that of the control group. The main results revealed that the subjects afflicted with whiplash injury on the average exhibited a faster response pattern than symptom-free healthy controls. Despite their  usculoskeletal deficits and experience of pain these volunteers also exhibited a preserved speed ^ accuracy tradeoff. Longer duration of time with symptoms of neck pain was, moreover, associated with progressively faster RTs. These results point to perceptual learning and may reflect different stages of adaptation to neck pain.

  • 620.
    Richter, Hans O.
    et al.
    University of Gävle, Centre for Musculoskeletal Research. University of Gävle, Department of Education and Psychology, Ämnesavdelningen för folkhälsovetenskap. Department of Optometry and Optical Science, Faculty of Physics and Mathematics, University of Latvia, Riga, Latvia.
    Wennberg, Patrik
    Department of Optometry and Optical Science, Faculty of Physics and Mathematics, University of Latvia, Riga, Latvia.
    Raudsepp, Jaanus
    University of Gävle, Centre for Musculoskeletal Research.
    The effects of inverting prisms on the horizontal-vertical illusion: a systematic effect of downward gaze2007In: Experimental Brain Research, ISSN 0014-4819, E-ISSN 1432-1106, Vol. 183, no 1, p. 9-15Article in journal (Refereed)
    Abstract [en]

    The purpose of this work is to compare the relative contributions from the extraocular and sensory systems on the magnitude of the horizontal-vertical illusion (HVI). The visual HVI refers to the general tendency to overestimate vertical extensions of small-scale lines on a picture plane relative to the horizontal by 4-16% depending on the method of measurement. The HVI line stimuli consisted of luminous vertical and horizontal lines forming "L-profiles" located in the frontoparallel plane at a 45 cm viewing distance, collinearly with a binocular gaze. The home position of gaze was aligned to the center of the screen with the ear-eye angle concordant with the environmental horizontal. Illusion strength was quantified when subjects fixated the HVI line stimuli in four quadrants of the visual field. The HVI was also viewed through prism lenses that inverted the retinal images by 180 degrees , thereby dissociating the sensory "up-down" direction from the oculomotor up-down frame of reference. The results revealed a systematically lower magnitude of the HVI in the bottom visual field regardless of whether subjects fixated the HVI with the distorting prisms or without. Taken together, these results suggest that the HVI is sensitive to small-angle gaze shifts. In agreement with several recent findings, these results are interpreted as implying that the brain imposes an enhanced analytic structure on the ascending sensory information during downward gaze.

  • 621.
    Richter, Hans O.
    et al.
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, CBF. University of Gävle, Centre for Musculoskeletal Research.
    Zetterlund, Christina
    The Low Vision Centre, Örebro County Council, Örebro, Sweden. Centre for Rehabilitation Research, Örebro University Hospital, Örebro, Sweden.
    Lundqvist, Lars-Olov
    Centre for Rehabilitation Research, Örebro University Hospital, Örebro, Sweden.
    Eye-neck interactions triggered by gaze control during visually deficient it-work probed by path analysis2010In: NES2010, 2010Conference paper (Refereed)
  • 622.
    Richter, Hans O.
    et al.
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, CBF. University of Gävle, Centre for Musculoskeletal Research.
    Zetterlund, Christina
    The Low Vision Centre, Örebro County Council, Örebro, Sweden, and Centre for Rehabilitation Research, Örebro University Hospital, Örebro, Sweden.
    Lundqvist, Lars-Olov
    Centre for Rehabilitation Research, Örebro University Hospital, Örebro, Sweden.
    Eye-neck interactions triggered by visually deficient computer work2011In: Work: A journal of Prevention, Assessment and rehabilitation, ISSN 1051-9815, E-ISSN 1875-9270, Vol. 39, no 1, p. 67-78Article in journal (Refereed)
    Abstract [en]

    Objectives: To study the joint occurrence of eye-and-neck/scapular area symptoms and their association with occupational risk factors in a cross-sectional sample of professional information technology users. Study population: The participants consisted of 3,971 employees who worked with computers for a minimum of one hour a day. 2,551 (73%) were men and 945 (27%) women, with an age range of 18 up to 64 years. The mean age was 38.1 (SD = 10.7) for men and 37.6 (SD = 12.0) for the women. The measures were obtained via a self-administered survey in combination with a visual examination conducted by an optometrist. Methods: Two complementary logistic regression analyses with forced entry was conducted on n = 3,496 (88% adjusted response rate) cases. The effect of ocular symptoms on the risk of reporting musculoskeletal symptoms, or vice versa, was examined first in two separate binominal logistic regression analyses. Age, Gender, Near work variable and Visual functioning variables were included in these analyzes. Variables associated with the risk of developing an increase in either symptom category were also examined in two additional binomial logistic regression analyses. Results: Exposure to spectacles (single vision, multifocal, or progressive correction) in combination with a visual acuity < 1 surfaced as a key mediator of symptoms from the neck/scapular area (p < 0.01). A vergence disparity (uncompensated vergence error) similarly was associated with an augmented risk of developing an increase in neck/scapular area symptoms (p < 0.05). The most influential risk factor for neck/scapular area symptoms were ocular symptoms and vice versa (p < 0.0001). Conclusions: The results support the hypothesis which postulates that eye-neck/scapular area symptoms interaction may be due to a functional coupling from and between the eye-neck/scapular area muscles [28].

  • 623.
    Richter, Hans
    et al.
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational Health Science and Psychology, Occupational Health Science. University of Gävle, Centre for Musculoskeletal Research.
    Sundin, Sofia
    Long, Jennifer
    School of Optometry and Vision Science, UNSW Sydney, Australia; Jennifer Long Visual Ergonomics, Katoomba, NSW, Australia.
    Visually deficient working conditions and reduced work performance in office workers: Is it mediated by visual well-being and health?2019In: International Journal of Industrial Ergonomics, ISSN 0169-8141, E-ISSN 1872-8219, Vol. 72, p. 128-136Article in journal (Refereed)
    Abstract [en]

    Introduction: The main purpose of this cross-sectional study was to investigate whether visual well-being and health act as a mediating factor between perceived visual ergonomic working conditions and self-rated visual performance among office workers who perform administrative tasks and computer-based work at the Swedish Tax Agency.

    Methods: A questionnaire was sent to 94 office workers addressing: 1) perceived visual quality of the visual display units; 2) prevalence of eye symptoms; and 3) self-rated visual performance. Eighty-six persons (54 women (63 %), 31 men (36 %), and 1 of unspecified sex) answered the questionnaire. Multiple regression analysis investigated the association between visual ergonomic working conditions and visual performance, with and without visual well-being and health as a mediator.

    Results: The group mean of the Indexed survey questions indicated reasonably good quality visual ergonomic working conditions, a relative absence of eye symptoms, and acceptable self-rated visual performance. Results from multiple regression analysis showed a significant association between perceived visual ergonomic working conditions and self-rated visual performance (r2 = 0.30, β = 0.327, p < 0.01). When visual well-being and health was used as a mediator, the association between perceived visual ergonomic working conditions and self-rated visual performance remained the same (r2 = 0.32, β = 0.315, p < 0.01).

    Discussion: It was surprising to discover that self-rated visual performance  was independent of visual health and well-being. Possible explanations include exposure factors not included in the current study, such as dry air and sensory irritation in eyes, psychosocial stress, time spent performing near work activities or time exposed to visually deficient working conditions. The strong connection between satisfaction with visual ergonomics work conditions and productivity found in this study has implications for workplace profitability and staff satisfaction. If productivity of office workers is improved by better visual ergonomics work conditions, then managers within workplaces may be able to improve work outcomes by optimizing the physical work environment.

    Download full text (pdf)
    fulltext
  • 624.
    Richter, Hans
    et al.
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, Occupational health science. University of Gävle, Centre for Musculoskeletal Research.
    Zetterberg, Camilla
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, Occupational health science. University of Gävle, Centre for Musculoskeletal Research.
    Forsman, Mikael
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, Occupational health science. University of Gävle, Centre for Musculoskeletal Research. Karolinska Institut, Stockholm, Sweden .
    Temporal Dependence of Trapezius Muscle Activation during Sustained Eye-Lens Accommodation at Near2013In: Lecture Notes in Computer Science, ISSN 0302-9743, E-ISSN 1611-3349, Vol. 8026, no 2, p. 269-275Article in journal (Refereed)
    Abstract [en]

    In this experimental study different levels of oculomotor load were induced via optical trial lenses. The aim was to investigate the temporal dependence of a moderate visual load on trapezius muscle activity. Trapezius muscle activity was measured with bipolar surface electromyography (EMG). Sixty-six subjects with a median age of 36 (range 19–47, std 8) viewed a black and white Gabor grating (5 c/deg) through 0 D, and -3.5 D lenses, in periods of 7-min. An auto refractor was used to continuously sample data on eye-lens accommodation during the vision tasks. Response-diopters were used as a dichotomous high/low accommodation grouping variable. For these groups EMG amplitudes during minutes 1-7 per each lens trial were studied separately with Generalized Estimating Equations (GEE). The analysis results showed significant increases in trapezius muscle activity over time for both viewing conditions. For the binocular -3.5 D condition response-diopters gave a significant positive contribution to the EMG amplitude. The results indicate that sustained eye-lens accommodation at near, during ergonomically unfavorable viewing conditions, may increase the risk for trapezius muscle myalgia.

  • 625.
    Richter, Hans
    et al.
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, Occupational health science. University of Gävle, Centre for Musculoskeletal Research.
    Zetterberg, Camilla
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, Occupational health science. University of Gävle, Centre for Musculoskeletal Research. Section of Occupational and Environmental Medicine, Department of Medical Sciences, Uppsala University, Uppsala, Sweden.
    Forsman, Mikael
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, Occupational health science. University of Gävle, Centre for Musculoskeletal Research. Division of Occupational and Environmental Medicine, Department of Public Health Sciences, Karolinska Institutet, Stockholm, Sweden.
    Trapezius muscle activity increases during near work activity regardless of accommodation/vergence demand level2015In: European Journal of Applied Physiology, ISSN 1439-6319, E-ISSN 1439-6327, Vol. 115, no 7, p. 1501-1512Article in journal (Refereed)
    Abstract [en]

    Aim

    To investigate if trapezius muscle activity increases over time during visually demanding near work.

    Methods

    The vision task consisted of sustained focusing on a contrast-varying black and white Gabor grating. Sixty-six participants with a median age of 38 (range 19–47) fixated the grating from a distance of 65 cm (1.5 D) during four counterbalanced 7-min periods: binocularly through −3.5 D lenses, and monocularly through −3.5 D, 0 D and +3.5 D. Accommodation, heart rate variability and trapezius muscle activity were recorded in parallel.

    Results

    General estimating equation analyses showed that trapezius muscle activity increased significantly over time in all four lens conditions. A concurrent effect of accommodation response on trapezius muscle activity was observed with the minus lenses irrespective of whether incongruence between accommodation and convergence was present or not.

    Conclusions

    Trapezius muscle activity increased significantly over time during the near work task. The increase in muscle activity over time may be caused by an increased need of mental effort and visual attention to maintain performance during the visual tasks to counteract mental fatigue.

  • 626.
    Richter, J M
    et al.
    Department of Neuroscience, Erasmus MC, Rotterdam, the Netherlands.
    Slijper, H P
    Department of Neuroscience, Erasmus MC, Rotterdam, the Netherlands.
    Mathiassen, Svend Erik
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences. University of Gävle, Centre for Musculoskeletal Research.
    Over, E A B
    Department of Neuroscience, Erasmus MC, Rotterdam, the Netherlands.
    Frens, M A
    Department of Neuroscience, Erasmus MC, Rotterdam, the Netherlands.
    The ability of computer activity recordings to estimate mechanical exposures during office work2008In: Proceedings of the International Conference on Ambulatory Monitoring of Physical Activity and Movement. Rotterdam, 2008Conference paper (Other academic)
  • 627.
    Richter, Janneke
    et al.
    Department of Neuroscience, Erasmus MC Rotterdam, the Netherlands.
    Mathiassen, Svend Erik
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, CBF. University of Gävle, Centre for Musculoskeletal Research.
    Slijper, Harm
    Department of Neuroscience, Erasmus MC Rotterdam, the Netherlands.
    Frens, Maarten
    Department of Neuroscience, Erasmus MC Rotterdam, the Netherlands.
    Differences in muscle load between computer and non-computer work among office workers2010In: Proceedings of the Premus 2010 conference, 2010, p. 272-Conference paper (Refereed)
  • 628.
    Richter, Janneke
    et al.
    University of Gävle, Centre for Musculoskeletal Research. University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences. Department of Neuroscience Erasmus MC, Rotterdam, Netherlands.
    Mathiassen, Svend Erik
    University of Gävle, Centre for Musculoskeletal Research. University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences.
    Slijper, Harm P.
    Department of Neuroscience Erasmus MC, Rotterdam, Netherlands.
    Over, Eelco A. B.
    Department of Neuroscience Erasmus MC, Rotterdam, Netherlands.
    Frens, Maarten
    Department of Neuroscience Erasmus MC, Rotterdam, Netherlands.
    Differences in muscle load between computer and non-computer work among office workers2009In: Ergonomics, ISSN 0014-0139, E-ISSN 1366-5847, Vol. 52, no 12, p. 1540-1555Article in journal (Refereed)
    Abstract [en]

    Introduction of more non-computer tasks has been suggested to increase exposure variation and thus reduce musculoskeletal complaints (MSC) in computer-intensive office work. This study investigated whether muscle activity did, indeed, differ between computer and non-computer activities. Whole-day logs of input device use in 30 office workers were used to identify computer and non-computer activities, using a range of classification thresholds (NCTs). Exposure during these activities was assessed by bilateral electromyography recordings from the upper trapezius and lower arm. Contrasts in muscle activity between computer and noncomputer activities were distinct but small, even at the individualized, optimal NCT. Using an average groupbased NCT resulted in less contrast, also if stratified by subgroups (job function, MSC). Computer activity logs should be used cautiously as proxies of biomechanical exposure. Conventional non-computer tasks may have a limited potential to increase exposure variation in computer-intensive office work.

  • 629. Order onlineBuy this publication >>
    Rissén, Dag
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, Occupational health science. University of Gävle, Centre for Musculoskeletal Research. Centrum för forskning och utveckling, Uppsala universitet/Landstinget Gävleborg.
    Psykosocial arbetsmiljö och (o)hälsa: ett biopsykosocialt stressperspektiv2014In: Hälsa, livsmiljö och arbetsliv: ur ett socialt arbete-perspektiv / [ed] Fereshteh Ahmadi & Sam Larsson, Gävle: Gävle University Press , 2014, p. 17-42Chapter in book (Other academic)
  • 630.
    Rissén, Dag
    et al.
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, Occupational health science. University of Gävle, Centre for Musculoskeletal Research. Centre for Research & Development, Uppsala University/Region of Gävleborg, Gävle, Sweden.
    Fjellman-Wiklund, Annchristine
    Department of Community Medicine and Rehabilitation, Physiotherapy, Umeå University.
    Röijezon, Ulrik
    Department of Health Science, Luleå University of Technology.
    Prevalence, intensity, and playing related consequences of musculoskeletal pain, and associations with mood among professional orchestra musicians: a pilot study2015Conference paper (Refereed)
    Abstract [en]

    Title: Prevalence, intensity, and playing related consequences of musculoskeletal pain, and associations with mood among professional orchestra musicians – a pilot study

    Aim: The aim of this cross-sectional study was to examine the 7-day prevalence, intensity, and consequences of musculoskeletal pain in the upper part of the body among professional musicians. Additional aims were to examine subjective mood and associations between mood and pain.

    Methods: This study is part of an ongoing national survey on musculoskeletal health conditions among professional musicians in Swedish symphony and opera orchestras. The data of this report is collected from two orchestras. Seventy-eight musicians (80%) participated, aged 45 ±9.6 years and 41% women. Results: Eighty percent of the musicians reported pain during the last 7 days. Pain was most frequent in the neck (59%) and the right shoulder (36%). The intensity of pain (11-point scale) was highest in the neck (mean 2.7, SD 1.8) and in the right hand (mean 2.7, SD 1.9). Playing related consequences were particularly related to pain in the left (71%) and right (54%) hands, and pain located to the left upper extremity did relatively more often affect playing performance compared to right side pain. Mood ratings showed that the musicians to a higher degree experienced “positive mood” (stimulated, concentrated, happy) compared to “negative mood” (stressed, exhausted, tense, nervous/anxious). Significant positive correlations were found between neck pain and stressed (rho=0.501, p=.000); neck pain and exhausted (rho=0.318, p=0.033); neck pain and tense (rho=0.314, p=0.034); and neck pain and nervous/anxious (rho=0.346, p=0.019). Significant correlations were not found between mood and pain in any other body region, except for a positive correlation between right shoulder and exhausted (rho=0.384, p=0.048).

    Conclusion: These preliminary results show a high 7-day prevalence of pain among professional musicians, especially in the neck. Left upper extremity and left and right hand pain needs special clinical attention due to high impact on playing performance. The results concerning associations between perceived “negative mood” and neck pain are supported by earlier findings (1,2) but need further exploration.

  • 631.
    Ristiniemi, Heli
    et al.
    Stress Clinic, Stockholm, Sweden.
    Perski, Aleksander
    Stress Research Institute Stockholm University, Stockholm, Sweden.
    Lyskov, Eugene
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, Occupational health science. University of Gävle, Centre for Musculoskeletal Research.
    Emtner, Margareta
    Department of Medical Sciences and Neuroscience Uppsala University, Uppsala, Sweden.
    Hyperventilation and exhaustion syndrome2014In: Scandinavian Journal of Caring Sciences, ISSN 0283-9318, E-ISSN 1471-6712, Vol. 28, no 4, p. 657-664Article in journal (Refereed)
    Abstract [en]

    Chronic stress is among the most common diagnoses in Sweden, most commonly in the form of exhaustion syndrome (ICD-10 classification – F43.8). The majority of patients with this syndrome also have disturbed breathing (hyperventilation). The aim of this study was to investigate the association between hyperventilation and exhaustion syndrome. Thirty patients with exhaustion syndrome and 14 healthy subjects were evaluated with the Nijmegen Symptom Questionnaire (NQ). The participants completed questionnaires about exhaustion, mental state, sleep disturbance, pain and quality of life. The evaluation was repeated 4 weeks later, after half of the patients and healthy subjects had engaged in a therapy method called ‘Grounding’, a physical exercise inspired by African dance. The patients reported significantly higher levels of hyperventilation as compared to the healthy subjects. All patients’ average score on NQ was 26.57 ± 10.98, while that of the healthy subjects was 15.14 ± 7.89 (t = −3.48, df = 42, p < 0.001). The NQ scores correlated strongly with two measures of exhaustion (Karolinska Exhaustion Scale KES r = 0.772, p < 0.01; Shirom Melamed Burnout Measure SMBM r = 0.565, p < 0.01), mental status [Hospital Anxiety and Depression Score (HADS) depression r = 0.414, p < 0.01; HADS anxiety r = 0.627, p < 0.01], sleep disturbances (r = −0.514, p < 0.01), pain (r = −.370, p < 0.05) and poor well-being (Medical Outcomes Survey Short Form 36 questionnaire- SR Health r = −0.529, p < 0.05). In the logistic regression analysis, the variance in the scores from NQ were explained to a high degree (R2 = 0.752) by scores in KES and HADS. The brief Grounding training contributed to a near significant reduction in hyperventilation (F = 2.521, p < 0.124) and to significant reductions in exhaustion scores and scores of depression and anxiety. The conclusion is that hyperventilation is common in exhaustion syndrome patients and that it can be reduced by systematic physical therapy such as Grounding.

  • 632.
    Riva, Roberto
    et al.
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, CBF. University of Gävle, Centre for Musculoskeletal Research. Department of Psychology, Stockholm University, Stockholm, Sweden.
    Mork, Paul Jarle
    Department of Human Movement Science, Norwegian University of Science and Technology, Trondheim, Norway.
    Westgaard, Rolf H
    Department of Industrial Economics and Technology Management, Norwegian University of Science and Technology, Trondheim, Norway.
    Lundberg, Ulf
    Department of Psychology, Stockholm University, Stockholm, Sweden; CHESS (Centre for Health Equity Studies), Stockholm University, Stockholm, Sweden.
    Comparison of the Cortisol Awakening Response in Women with Shoulder and Neck Pain and Women with Fibromyalgia2012In: Psychoneuroendocrinology, ISSN 0306-4530, E-ISSN 1873-3360, Vol. 37, no 2, p. 299-306Article in journal (Refereed)
    Abstract [en]

    Shoulder and neck pain (SNP) and fibromyalgia syndrome (FMS), two musculoskeletal conditions of unknown pathogenesis, share some common features in terms of altered neuroendocrine responses, pain and stress perception. However, the pain distribution in SNP is localized, whereas in FMS is more widespread. Because regional musculoskeletal pain may represent an intermediate stage along a continuum towards widespread musculoskeletal pain we compared the cortisol awakening response (CAR) in women with SNP with the CAR in FMS patients and healthy controls (HC) in a controlled hospital-hotel setting. The aim of the study was to investigate whether SNP is related to a deviant regulation of the hypothalamic-pituitary-adrenal (HPA) axis. Eighteen women with SNP, 29 female FMS patients, and 27 female HC participated in the study. Cortisol samples were collected upon awakening, 30 and 60 min later. Questionnaires measuring pain levels, sleeping problems, perceived stress, and psychological characteristics were administered to the participants. Compared with HC, women with SNP had a tendency towards higher cortisol levels, whereas FMS had lower cortisol levels. Adjustment for potential confounders did not influence the results. Women with SNP and FMS patients reported more health complaints, pain, and perceived stress than the HC, but women with SNP were less affected than the FMS patients. Women with SNP showed a tendency towards an elevated HPA axis activity compared with HC. The current findings may indicate that the hypercortisolism in regional musculoskeletal pain represent an intermediate stage towards the development of a hypocortisolism in widespread musculoskeletal pain.

  • 633.
    Rolfer, Bengt
    et al.
    Rolfer media & kommunikation.
    Mathiassen, Svend ErikUniversity of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, CBF. University of Gävle, Centre for Musculoskeletal Research.Vingård, EvaArbets- och miljömedicin, Uppsala universitet.
    Forskning i fara?: Forskarna själva om dagens svenska arbetsmiljöforskning2012Collection (editor) (Other (popular science, discussion, etc.))
  • 634.
    Rolfer, Bengt
    et al.
    Rolfer media & kommunikation.
    Mathiassen, Svend Erik
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, CBF. University of Gävle, Centre for Musculoskeletal Research.
    Vingård, Eva
    Arbets- och miljömedicin, Uppsala universitet.
    Vart är Sveriges arbetsmiljöforskning på väg?2012In: Forskning i fara?: Forskarna själva om dagens svenska arbetsmiljöforskning / [ed] Bengt Rolfer, Svend Erik Mathiassen, Eva Vingård, Gävle: Gävle University Press , 2012Chapter in book (Other (popular science, discussion, etc.))
  • 635.
    Rolfö, L.
    et al.
    Department of Ergonomics, KTH Royal Institute of Technology, Huddinge, Sweden.
    Jahncke, Helena
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational Health Science and Psychology, Occupational Health Science. University of Gävle, Centre for Musculoskeletal Research.
    Järvholm, L. S.
    Department of Public Health and Clinical Medicine, Umeå University, Umeå, Sweden.
    Öhrn, M.
    Department of Public Health and Clinical Medicine, Umeå University, Umeå, Sweden.
    Babapour, M.
    Department of Industrial and Materials Science, Chalmers University of Technology, Gothenburg, Sweden.
    Predictors of Preference for the Activity-based Flexible Office2019In: Human Systems Engineering and Design: Proceedings of the 1st International Conference on Human Systems Engineering and Design (IHSED2018) / [ed] Tareq Ahram, Waldemar Karwowski, and Redha Taiar, Cham: Springer, 2019, p. 547-553Conference paper (Refereed)
    Abstract [en]

    Activity-based Flexible Offices (A-FOs) are implemented with varying degree of success. Employees relocate from cell or open-plan offices, from different organizational backgrounds, varying design and implementation processes, and have different types of work tasks. This study aims at investigating whether preference for the A-FO correlate with these preconditions. The results from Chi-square tests and Spearman’s non-parametric correlation of post-relocation questionnaires distributed to 11 A-FO sites, showed that a high preference for the A-FO correlated strongest with an A-FO preference prior to relocation, being a former open-plan office occupier and with frequent performance of innovation. Low preference for the A-FO correlated with frequent performance of concentration demanding tasks. Working with tasks with high confidentiality did not predict the preference ratings.

  • 636.
    Rolfö, Linda
    et al.
    Unit of Ergonomics, School of Technology and Health, KTH, Stockholm, Sweden.
    Eklund, Jörgen
    Unit of Ergonomics, School of Technology and Health, KTH, Stockholm, Sweden.
    Jahncke, Helena
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, Occupational health science. University of Gävle, Centre for Musculoskeletal Research.
    Perceptions of performance and satisfaction after relocation to an activity-based office2018In: Ergonomics, ISSN 0014-0139, E-ISSN 1366-5847, Vol. 61, no 5, p. 644-657Article in journal (Refereed)
    Abstract [en]

    Many companies move from open-plan offices (OPO) to activity-based workplaces (ABWs). However, few studies examine the benefits and drawbacks following such a change. The aim of this study was to explore how physical conditions, office use, communication, privacy, territoriality, satisfaction and perceived performance change following a company's relocation from an OPO to an ABW. A mixed methods approach included pre- and post-relocation questionnaires and post-relocation focus groups, individual interviews and observations. The questionnaires enabled comparisons over time (n = 34) and broader analyses based on retrospective ratings of perceived change (n = 66). Results showed that satisfaction with auditory privacy, background noise, air quality, outdoor view and aesthetics increased significantly after relocation. Negative outcomes, such as lack of communication within teams, were perceived as being due to the high people-to-workstation ratio and lack of rules. Overall satisfaction with the physical work environment increased in the ABW compared to the OPO. Perceived performance did not change significantly. Practitioner Summary: Activity-based workplaces (ABWs) are commonly implemented although their effects on performance and well-being are unclear. This case study gives advice to stakeholders involved in office planning. Despite shortcomings with the people-to-workstation ratio and rules, employees showed improved satisfaction with auditory privacy and aesthetics in the ABW compared with the previous open-plan office.

  • 637.
    Ross, Alastair B
    et al.
    Department of Genetics and Pathology, Rudbeck Laboratory, Uppsala University, Sweden; Nestlé Research Center, Lausanne, Switzerland.
    Johansson, Åsa
    Department of Genetics and Pathology, Rudbeck Laboratory, Uppsala University, Sweden.
    Vavruch-Nilsson, Veronika
    Department of Genetics and Pathology, Rudbeck Laboratory, Uppsala University, Sweden.
    Hassler, Sven
    Southern Lappland Research Department, Vilhelmina, Sweden.
    Sjölander, Per
    University of Gävle, Centre for Musculoskeletal Research. Southern Lappland Research Department, Vilhelmina, Sweden.
    Edin-Liljegren, Anette
    Southern Lappland Research Department, Vilhelmina, Sweden.
    Gyllensten, Ulf
    Department of Genetics and Pathology, Rudbeck Laboratory, Uppsala University, Sweden.
    Adherence to a traditional lifestyle affects food and nutrient intake among modern Swedish Sami2009In: International Journal of Circumpolar Health, ISSN 1239-9736, E-ISSN 2242-3982, Vol. 68, no 4, p. 372-385Article in journal (Refereed)
    Abstract [en]

    Objectives. To compare the nutrient and food intake of Sami still engaged in reindeer herding (traditional lifestyle or reindeer-herding Sami [RS]) and Sami not involved in reindeer herding (industrialized lifestyle or non-reindeer-herding Sami [NRS]) with other northern Swedish populations. Study design. Cross-sectional analysis of data from a prospective cardiovascular intervention program in northern Sweden. Methods. Data were used from a prospective cardiovascular intervention program in northern Sweden. Sami recruited into this study were divided according to whether they were involved in reindeer herding (traditional lifestyle, RS) (66 females, 79 males) or not (NRS) (255 females, 195 males), and compared to non-Sami from the same area taking part in the same study (controls) (499 females, 501 males). Subjects completed a Food Frequency Questionnaire (FFQ) and clinical parameters were analysed. Results. RS had a higher overall intake of energy for both females (P<0.01) and males (P<0.05), but not total food intake compared to controls and NRS. The overall Sami diet was characterized by a higher proportion of energy from protein and fat. RS had a lower energy adjusted intake of vitamins A and E, and fibre, and a higher intake of sodium. RS and NRS both had a lower intake of vegetables and a higher intake of meat, and for RS, fish. Nutrient and food-intake patterns were similar for males and females. Conclusions. Classification of Sami into RS and NRS indicates that a traditional lifestyle defined by occupation is reflected in differences in food and nutrient intake.

  • 638.
    Rudolfsson, Thomas
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, Occupational health science. University of Gävle, Centre for Musculoskeletal Research. Umeå universitet, Sjukgymnastik.
    Sensorimotor control and cervical range of motion in women with chronic neck pain: Kinematic assessments and effects of neck coordination exercise2014Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Introduction: Neck pain is a common problem in society and is more prevalent among women. The consequences of neck pain for the individual often include activity and participation limitations, thus affecting many dimensions of life. There is still a lack of understanding of the underlying mechanisms of the disorder and likewise of efficient rehabilitation for people with neck pain. However, coordination exercises have shown promising short-term effects. To carry this line of research forward, there is a need to improve methods for objective characterization of impairments and to investigate novel methods of rehabilitation.

    Aims: To characterize impairments of active cervical range of motion of the upper and lower cervical levels in women with chronic neck pain with a novel method (Study I and II) and identify the influence of head posture and movement strategies (Study II). Further, to investigate the effects of a novel method for neck coordination exercise on sensorimotor function and neck pain (study III) and the consistencies of motor variability metrics in a goal directed arm movement task to aid the design of future clinical research (Study IV).

    Methods: All studies were laboratory based with kinematic assessments of neck movements (Study I-III), balance (Study III) and goal directed arm movements (Study III, IV). The studies had designs that were: cross-sectional (I and II), randomized controlled trial (III) or test-retest reliability study (IV). Participants in Study I (n=135) and II (n=160) were women with chronic non-specific neck pain and healthy controls. In Study III, women with chronic non-specific neck pain (n=108) were randomized into three different individually supervised 11 week interventions. Study IV included healthy women (n=14).

    Results: It was found that cervical range of motion impairments in women with non-specific neck pain were direction- and level-specific; impairments were greater in extension in the upper and flexion in the lower levels of the cervical spine. The magnitude of impairments in range of motion was associated to self-ratings of functioning and health. Possible group differences in natural head posture were rejected as a cause for the direction specific effects. Neither could the effects be explained by a strategy to minimize torque in the cervical spine during movement execution. The neck coordination training was not superior to strength training (best-available) and massage treatment (sham) in improving sensorimotor functions or pain according to short-term and 6 months follow ups. The results from the study of the goal directed movement task showed that between and within-subject sizes of most motor variability metrics were too large to make the test suitable for application in clinical research.

    Conclusions: Women with chronic non-specific neck pain have direction- and level-specific impairments in cervical sagittal range of motion. The underlying causes of these specific impairments remains unresolved, but the direction specific impairments are not related to natural head posture. The clinical validity of the method of characterization of cervical range of motion was supported and it can be useful in future clinical research. The novel method of neck coordination exercise showed no advantages on sensorimotor functions or pain compared with best-available treatment in women with chronic non-specific neck pain.

  • 639.
    Rudolfsson, Thomas
    et al.
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, CBF. University of Gävle, Centre for Musculoskeletal Research.
    Björklund, Martin
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, CBF. University of Gävle, Centre for Musculoskeletal Research.
    Djupsjöbacka, Mats
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, CBF. University of Gävle, Centre for Musculoskeletal Research.
    Range of motion in the upper and lower cervical spine in people with chronic neck pain2012In: Manual Therapy, ISSN 1356-689X, E-ISSN 1532-2769, Vol. 17, no 1, p. 53-59Article in journal (Refereed)
    Abstract [en]

    Reduced cervical range of motion (ROM) is a common finding in people with neck pain. With few exceptions, only the angle between head and thorax has been measured. Our aim was to use an extended model to compare active cervical flexion and extension, separate for upper and lower cervical levels, between people with chronic non-traumatic neck pain and controls. We also investigated associations between ROM measures, symptoms and self-rated functioning. In this cross-sectional study, 102 subjects with neck pain and 33 healthy controls participated. An electromagnetic tracker system was used to measure the kinematics to construct a three-segment model including the thorax, cervical spine and head. Neutral flexion/extension were defined at subjects’ self-selected seated posture. We found that in the neck pain group, extension in the upper cervical levels and predominately flexion for the lower levels were reduced. The ratio between ROM for the upper and lower levels was altered in the neck pain group so that the lower levels contributed to a lesser extent to the total sagittal ROM compared to controls. These findings could not be explained by a greater forward head posture but must have other origins. For the neck pain group, ROM measures were weakly associated to pain and self-rated functioning. Altogether, this implies that using a three-segment model for assessment of ROM can be a valuable improvement for characterisation of patients and treatment evaluation.

  • 640.
    Rudolfsson, Thomas
    et al.
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, CBF. University of Gävle, Centre for Musculoskeletal Research.
    Björklund, Martin
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, CBF. University of Gävle, Centre for Musculoskeletal Research.
    Djupsjöbacka, Mats
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, CBF. University of Gävle, Centre for Musculoskeletal Research.
    Range of motion in the upper and lower cervical spine in people with chronic neck pain2010In: The XVIII Congress of the International Society of Electrophysiology and Kinesiology (ISEK), Aalborg, Denmark, 2010Conference paper (Refereed)
    Abstract [en]

    AIM: Several studies have reported reduced cervical range of motion (ROM) in people with neck pain. Different methodologies have been used, but with a few exception they measure only head-trunk relationship and do not discriminate between upper and lower cervical motion. Recent strategies for treatment of neck pain condition include retraining the function of the deep cervical flexors that act in cranio-cervical movements. Thus objective measures of cervical ROM in flexion-extension that includes determination of cervical level can be valuable for treatment evaluation.

    The aim of the present study was to compare cervical flexion and extension, separate for upper and lower cervical levels, between people with chronic neck pain and controls. Also, the association between upper and lower cervical ROM and self rated characteristics was studied.

    METHODS: In a cross-sectional study design, 135 subjects (non-traumatic neck pain: n = 102, controls: n = 33) performed three trials of maximum active cervical flexion and extension. Subjects were seated in a chair with belts crossed over the chest. An electromagnetic tracker system was used to register the kinematics to construct a three-segment model including the trunk, cervical spine and head. The angle for the upper cervical level was defined as the angle between the head and the cervical spine segments. The angle for the lower cervical level was defined as the angle between the cervical spine and the trunk segments. Pressure pain thresholds, pain ratings as well as self ratings of functioning and physical activity were assessed.

    RESULTS: Total ROM was reduced in the neck pain group for both the lower (controls: mean = 26.5, SD=6.7, neck pain: mean=19.0, SD =6.5 degrees) and the upper cervical levels (controls: mean = 84.7, SD = 7.9, neck pain: mean = 73.0, SD = 11.2 degrees). This reduction was direction specific: in the upper cervical level only extension was reduced and in the lower cervical level the reduction was predominately in flexion. Multivariate regression analysis revealed that lower level of physical activity, greater impairments of physical functioning, self reported problems with head movements and lower pressure pain thresholds were related to a greater reduction in ROM in the neck pain group.

    CONCLUSION: Reduction of ROM is present for both the upper and lower levels of the cervical spine in people with non-traumatic neck pain. For the upper cervical level this reduction is direction specific so that only extension is reduced. The limited extension range of the upper cervical spine in the neck pain group could reflect a habituated sitting posture that includes a more extended upper cervical spine. Alternatively it could reflect an impaired functioning of the deep cervical flexors. For the lower cervical level the reduction was mainly limited to flexion. This could be a reflection of a ‘head forward posture’ that has previously been reported in people with neck pain. The associations between self rated characteristics and range of motion variables supports the validity of this methodology in research on neck pain conditions.

  • 641.
    Rudolfsson, Thomas
    et al.
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, Occupational health science. University of Gävle, Centre for Musculoskeletal Research. Department of Community Medicine and Rehabilitation, Physiotherapy, Umeå University, Umeå, Sweden.
    Björklund, Martin
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, Occupational health science. University of Gävle, Centre for Musculoskeletal Research. Department of Community Medicine and Rehabilitation, Physiotherapy, Umeå University, Umeå, Sweden.
    Svedmark, Åsa
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, Occupational health science. University of Gävle, Centre for Musculoskeletal Research. Department of Community Medicine and Rehabilitation, Physiotherapy, Umeå University, Umeå, Sweden.
    Srinivasan, Divya
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, Occupational health science. University of Gävle, Centre for Musculoskeletal Research.
    Djupsjöbacka, Mats
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, Occupational health science. University of Gävle, Centre for Musculoskeletal Research.
    Direction-specific impairments in cervical range of motion in women with chronic neck pain: influence of head posture and gravitationally induced torque2017In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 12, no 1, article id e0170274Article in journal (Refereed)
    Abstract [en]

    Background: Cervical range of motion (ROM) is commonly assessed in clinical practice and research. In a previous study we decomposed active cervical sagittal ROM into contributions from lower and upper levels of the cervical spine and found level- and direction-specific impairments in women with chronic non-specific neck pain. The present study aimed to validate these results and investigate if the specific impairments can be explained by the neutral posture (defining zero flexion/extension) or a movement strategy to avoid large gravitationally induced torques on the cervical spine.

    Methods: Kinematics of the head and thorax was assessed in sitting during maximal sagittal cervical flexion/extension (high torque condition) and maximal protraction (low torque condition) in 120 women with chronic non-specific neck pain and 40 controls. We derived the lower and upper cervical angles, and the head centre of mass (HCM), from a 3-segment kinematic model. Neutral head posture was assessed using a standardized procedure.

    Findings: Previous findings of level- and direction-specific impairments in neck pain were confirmed. Neutral head posture was equal between groups and did not explain the direction-specific impairments. The relative magnitude of group difference in HCM migration did not differ between high and low torques conditions, lending no support for our hypothesis that impairments in sagittal ROM are due to torque avoidance behaviour.

    Interpretation: The direction- and level-specific impairments in cervical sagittal ROM can be generalised to the population of women with non-specific neck pain. Further research is necessary to clarify if torque avoidance behaviour can explain the impairments.

  • 642.
    Rudolfsson, Thomas
    et al.
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, Occupational health science. University of Gävle, Centre for Musculoskeletal Research. Umeå universitet.
    Djupsjöbacka, Mats
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, Occupational health science. University of Gävle, Centre for Musculoskeletal Research.
    Häger, Charlotte
    Umeå universitet.
    Björklund, Martin
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, Occupational health science. University of Gävle, Centre for Musculoskeletal Research. Umeå universitet, Alfta Research Foundation.
    Effects of neck coordination exercise on sensorimotor function in chronic neck pain: a randomized controlled trial2014In: Journal of Rehabilitation Medicine, ISSN 1650-1977, E-ISSN 1651-2081, Vol. 46, no 9, p. 908-914Article in journal (Refereed)
    Abstract [en]

    Objective: To evaluate the effect of neck coordination exercise on sensorimotor function in women with neck pain compared with best-available treatment and sham treatment. Design: Observer-blinded randomized controlled trial with short-term and 6-month follow-ups. Subjects: Women with chronic non-specific neck pain were randomized to 3 groups: neck coordinationexercise with a novel training device; strength training for the neck and shoulders; or massage. Each group had 36 participants. Methods: The intervention period was 11 weeks with 22 individually supervised sessions. Primary outcomes were postural sway measures and precision of goal-directed arm movements. Secondary outcomes were range of motion for the neck, peak speed of axial rotation, and neck pain. A repeated measures multivariate analysis of variance (MANOVA) was conducted separately on the primary outcomes for the short-term and 6-month evaluations and on the sensorimotor secondary outcomes for the 6-month effect. The 6-month effect on pain was analysed with a repeated measures analysis ofvariance (ANOVA). Results: No significant treatment effects in favour of neck coordination exercise were found for short-term or 6-month evaluations. Conclusion: Neck coordination exercise is no better than strength training and massage in improvingsensorimotor function. Further research should investigate the use of cutoffs for sensorimotordysfunctions prior to proprioceptive or coordinative training.

  • 643.
    Rudolfsson, Thomas
    et al.
    University of Gävle, Centre for Musculoskeletal Research.
    Domkin, Dmitry
    University of Gävle, Centre for Musculoskeletal Research.
    Björklund, Martin
    University of Gävle, Centre for Musculoskeletal Research.
    Djupsjöbacka, Mats
    University of Gävle, Centre for Musculoskeletal Research.
    Is neck pain associated with altered body sway kinematics?2009In: Sjukgymnastdagarna, Stockholmsmässan i Älvsjö, Stockholm: Legitimerade Sjukgymnasters Riksförbund, Stockholm , 2009, p. -40Conference paper (Other academic)
    Abstract [en]

    Introduction:Several studies have reported impaired postural control in people with neck pain. Many of these studies have analysed centre of pressure data from a force plate in quiet standing but to our knowledge none has investigated the kinematics of postural sway in people with neck pain. From studies on healthy controls there are two well established strategies of maintaining upright stance: hip and ankle strategies. Recent work has shown that these co-exist simultaneously. The purpose of this study is to investigate these kinematic strategies in people with neck pain. This could give a greater understanding of the mechanisms behind the postural control impairments and give implications for specific rehabilitation interventions.Methods:Seventy subjects (neck pain n=44, controls n=26) stood with their feet together, arms crossed and their eyes closed for 180 s. An electromagnetic tracker was used to record the kinematics for a two segment model (leg, trunk). An in-phase pattern between these segments corresponds to ankle strategy and an anti-phase pattern to hip-strategy. The strength of the in-phase pattern was quantified using coherence analysis.Results:Preliminary results indicate that people with neck pain rely less on ankle strategy in quiet standing than healthy controls. There were no differences in variability of the segment angles between groups. However people with neck pain tended to stand with a greater degree of extension in the hip.Conclusion:It’s generally considered that hip-strategy is used more when the difficulty of the task is higher. One speculative interpretation to the weaker ankle strategy in the neck pain group is that they perceived the task as more demanding. The method of coherence analysis used in this study can be a valuable tool in future studies for understanding postural sway in people with spinal pain.

  • 644.
    Röijezon, Ulrik
    University of Gävle, Centre for Musculoskeletal Research.
    Sensorimotor function in chronic neck pain: objective assessments and a novel method for neck coordination exercise2009Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Chronic neck pain is a widespread problem that causes individual suffering as well as large costs for the society. The knowledge about the pathophysiology is poor and therefore specific diagnosis and causal treatment are rare. Important knowledge for characterization of the disorders has been gained from research on sensorimotor functions in people with neck pain. Moreover, rehabilitation regimes including sensorimotor exercises indicate promising results. The main objectives of this thesis were to extend the knowledge on sensorimotor dysfunctions in chronic neck pain, and to develop a new exercise method for improving sensorimotor functions of the neck. The studies focused on aspects of postural control and movements of the arm and neck. These are vital functions for many activities of daily living. People with chronic (>3 months) neck pain were compared to healthy controls (CON). Neck pain related to trauma was referred to as whiplash associated disorders (WAD), while neck pain without association to trauma was referred to as non-specific (NS). Arm-functioning was assessed in a pointing task. WAD and NS had reduced pointing precision compared to CON. The reduced precision was associated with self-rated difficulties performing neck movements, physical functioning, and in WAD, also pain and balance disturbances. Postural control was assessed in quiet standing on a force platform without vision. The center of pressure signal was decomposed into it’s slow and fast components. WAD and NS were compared to CON. The results revealed an effect of age on the magnitude of the fast sway component, but no effect of group. The magnitude of the slow component was elevated in both WAD and NS. This increase was associated with self-rated balance disturbance, arm-functioning, difficulties to run and sensory alterations in WAD, while in NS, the increase in the slow sway component was associated with concurrent low back pain. Neck movements were assessed in a cervical axial rotation test with maximal speed. In total 8 variables representing basic kinematics, including variables reflecting movement smoothness and conjunct motions were calculated. NS were compared to CON. Linear discriminant modelling indicated Peak Speed and conjunct motions as significant classification variables that together had a sensitivity of 76.3% and specificity of 77.6%. Retest reliability was good for Peak Speed but poor for the measure of conjunct motions. Peak Speed was slower in NS compared to CON, and even slower in a sub-group of NS with concurrent low back pain. Reduced Peak Speed was associated with self-rated difficulties performing neck movements, car driving, running, sleeping disturbances and pain. The clinical applicability of a novel method for neck coordination exercise was assessed in a pilot study on persons with NS. The results supported the applicability and indicated positive effects of the exercise: reduced postural sway in quiet standing and increased smoothness in cervical rotations. Indications on improvement in self-rated disability and fear of movement were seen at six months follow up. In conclusion, sensorimotor functions can be altered in chronic neck pain, particularly in neck disorders with concurrent low back pain and WAD. The discriminative ability and clinical validity displayed in pointing precision, postural sway and cervical axial rotation speed imply that such tests can be valuable tools in the assessment of chronic neck pain patients, and for selecting and evaluating treatment interventions. Indications of improvements seen in the pilot-study support a future RCT.

  • 645.
    Röijezon, Ulrik
    et al.
    Department of Health Science, Luleå University of Technology.
    Ardel, Dag
    Department of Community Medicine & Rehabilitation, Physiotherapy, Umeå University.
    Rissén, Dag
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, Occupational health science. University of Gävle, Centre for Musculoskeletal Research. Centre for Research & Development, Uppsala University/Region of Gävleborg, Gävle, Sweden.
    Juul-Kristensen, Birgit
    Institute of Sports Science and Clinical Biomechanics, University of Southern Denmark.
    Generalised Joint Hypermobility and musculoskeletal pain among professional classical orchestra musicians in Sweden: a pilot study2015Conference paper (Refereed)
    Abstract [en]

    Aims: The aims were to 1) investigate the presence of Generalised Joint Hypermobility (GJH) and musculoskeletal pain among musicians in professional Swedish symphony and opera orchestras, and 2) investigate associations between GJH and musculoskeletal pain.

    Methods: A Swedish version of the 5-part questionnaire [1] and the standardised Nordic questionnaire for musculoskeletal pain disorders [2] were included in an ongoing national survey on musculoskeletal health conditions among professional orchestra musicians in Sweden. The data of this report is collected from two orchestras. Seventy-eight musicians (80%) participated, aged 45 ±9.6 years with 41% women.

    Results: At present, 77 participants completed the 5-part questionnaire, of which 19.5% (28% of the women and 13% of the men) scored two or more on the 5-part questionnaire, which is the criteria for GJH. Pain prevalence during the last 12 months was highest for the neck (73.7%) and lowest for the left and right elbows (15.6% and 16.9%, respectively) (Table 1). Binary logistic regressions revealed that hypermobility was associated with increased risk for pain conditions at the neck (Odds Ratio 5.64, p=0.005) and the left and the right hand (Odds Ratio 1.80, p=0.019 and Odds Ratio 1.68, p=0.032, respectively) (Table 1).

    Discussion/Conclusion: Previous studies have reported various results regarding hypermobility and association with musculoskeletal pain conditions, including both increased and reduced risk [3- 5]. Our study shows increased risk of pain located to the neck and both hands among musicians with GJH, while no significant increased or decreased risks were seen for the other body parts. However, larger groups of musicians should confirm the influence of GJH on musculoskeletal pain, and whether it differs between men and women and between groups of instruments. The current preliminary results may indicate that GHJ among musicians should be identified and preventive strategies be recommended, e.g., regarding pauses, posture and physical exercises.

  • 646.
    Röijezon, Ulrik
    et al.
    University of Gävle, Centre for Musculoskeletal Research. Department of Community Medicine and Rehabilitation, Physiotherapy, University of Umeå, Umeå, Sweden; Alfta Research Foundation, Alfta, Sweden.
    Björklund, Martin
    University of Gävle, Centre for Musculoskeletal Research. Alfta Research Foundation, Alfta, Sweden.
    Bergenheim, Mikael
    University of Gävle, Centre for Musculoskeletal Research. Department of Surgery, Central Hospital Karlstad, Karlstad, Sweden.
    Djupsjöbacka, Mats
    University of Gävle, Centre for Musculoskeletal Research.
    A novel method for neck coordination exercise: a pilot study on persons with chronic non-specific neck pain2008In: Journal of NeuroEngineering and Rehabilitation, ISSN 1743-0003, E-ISSN 1743-0003, Vol. 5, article id 36Article in journal (Refereed)
    Abstract [en]

    BACKGROUND: Chronic neck pain is a common problem and is often associated with changes in sensorimotor functions, such as reduced proprioceptive acuity of the neck, altered coordination of the cervical muscles, and increased postural sway. In line with these findings there are studies supporting the efficacy of exercises targeting different aspects of sensorimotor function, for example training aimed at improving proprioception and muscle coordination. To further develop this type of exercises we have designed a novel device and method for neck coordination training. The aim of the study was to investigate the clinical applicability of the method and to obtain indications of preliminary effects on sensorimotor functions, symptoms and self-rated characteristics in non-specific chronic neck pain METHODS: The study was designed as an uncontrolled clinical trial including fourteen subjects with chronic non-specific neck pain. A new device was designed to allow for an open skills task with adjustable difficulty. With visual feedback, subjects had to control the movement of a metal ball on a flat surface with a rim strapped on the subjects' head. Eight training sessions were performed over a four week period. Skill acquisition was measured throughout the intervention period. After intervention subjects were interviewed about their experience of the exercise and pain and sensorimotor functions, including the fast and slow components of postural sway and jerkiness-, range-, position sense-, movement time- and velocity of cervical rotation, were measured. At six-month follow up, self-rated pain, health and functioning was collected. RESULTS: The subjects improved their skill to perform the exercise and were overall positive to the method. No residual negative side-effects due to the exercise were reported. After intervention the fast component of postural sway (p = 0.019) and jerkiness of cervical rotation (p = 0.032) were reduced. The follow up showed decreased disability (one out of three indices) and fear of movement, and increased general health (three out of eight dimensions). CONCLUSION: The results support the clinical applicability of the method. The improvements in sensorimotor functions may suggest transfer from the exercise to other, non-task specific motor functions and justifies a future randomized controlled trial.

  • 647.
    Röijezon, Ulrik
    et al.
    University of Gävle, Centre for Musculoskeletal Research.
    Björklund, Martin
    University of Gävle, Centre for Musculoskeletal Research.
    Djupsjöbacka, Mats
    University of Gävle, Centre for Musculoskeletal Research.
    A novel method of neck coordination exercise: effects on sensorimotor functions and self reported health and functioning2007In: 15th International WCPT Congress, World Physical Therapy, 2007Conference paper (Refereed)
    Abstract [en]

    INTRODUCTION: The efficacy of exercises targeting sensorimotor functions in treatment of neck pain is increasingly acknowledged. To further develop this type of exercises we have designed a novel device (patent pending) and method for neck coordination training. The purpose of this study was to obtain indications of the usability of the method and its effects on sensorimotor functions, pain and functioning in neck pain patients. METHODS: Subjects with non-traumatic chronic neck pain (n=14) participated in this uncontrolled clinical trial. The neck exercise was an open skills task with adjustable difficulty. With visual feedback, subjects had to control the movement of a metal ball on a flat surface with a rim which was strapped on the subjects’ head. Before and after the intervention (eight sessions), pain ratings, postural sway and jerkiness-, range-, position sense-, movement time- and velocity of cervical rotation were assessed. At six-month follow up self rated pain, health and functioning was collected. RESULTS: Patients were overall positive to the exercise. A significant reduction in postural sway and jerkiness of cervical rotation was revealed after the training. The six-month follow up showed decreased disability and fear of movement, as well as increased general health and well being. CONCLUSION: The results support the clinical applicability of the method. The improved sensorimotor functions suggest transfer from the exercise to more general, non-task specific motor functions. The follow up may indicate a long term beneficial effect.

  • 648.
    Röijezon, Ulrik
    et al.
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, CBF. University of Gävle, Centre for Musculoskeletal Research.
    Björklund, Martin
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, CBF. University of Gävle, Centre for Musculoskeletal Research.
    Djupsjöbacka, Mats
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, CBF. University of Gävle, Centre for Musculoskeletal Research.
    The slow and fast components of postural sway in chronic neck pain2011In: Manual Therapy, ISSN 1356-689X, E-ISSN 1532-2769, Vol. 16, no 3, p. 273-278Article in journal (Refereed)
    Abstract [en]

    Background: Several studies have reported altered postural control in people with neck pain. The aim of this study was to increase the understanding of the nature of altered postural control in neck pain by studying the slow and fast components of body sway. Methods: Subjects with whiplash associated disorders (WAD, n = 21) and chronic non-specific neck pain (NS, n = 24) were compared to healthy controls (CON, n = 21) in this cross-sectional study. The magnitudes of the slow and fast sway components were assessed in Rhomberg quiet stance for 30 s on a force plate with eyes closed. We also investigated associations between postural sway and symptoms, self-ratings of functioning and kinesiophobia. Results: Increased magnitude of the slow sway component was found in WAD, but not in NS. Greater magnitude of the slow component in WAD was associated with poorer physical functioning, including balance disturbances, and more severe sensory symptoms. Conclusions: Increased magnitude of the slow sway component implies an aberration in sensory feedback or processing of sensory information in WAD. The associations between postural sway and self-rated characteristics support the clinical validity of the test. Further investigation into NS, involving a longer test time is warranted. (C) 2010 Elsevier Ltd. All rights reserved.

  • 649.
    Röijezon, Ulrik
    et al.
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, CBF. University of Gävle, Centre for Musculoskeletal Research. Alfta Research Foundation, Alfta, Sweden.
    Djupsjöbacka, Mats
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, CBF. University of Gävle, Centre for Musculoskeletal Research.
    Björklund, Martin
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, CBF. University of Gävle, Centre for Musculoskeletal Research. Alfta Research Foundation, Alfta, Sweden.
    Häger-Ross, Charlotte
    Department of Community Medicine and Rehabilitation, Physiotherapy, Umeå University, Umeå, Sweden.
    Grip, Helena
    Department of Biomedical Engineering & Informatics, University Hospital of Umeå, Umeå, Sweden; Department of Biomedical Engineering and Informatics, University Hospital of Umeå, Umeå, Sweden .
    Liebermann, Dario G.
    Department of Physical Therapy, Sackler Faculty of Medicine, Tel Aviv University, Israel.
    Kinematics of fast cervical rotations in persons with chronic neck pain: a cross-sectional and reliability study2010In: BMC Musculoskeletal Disorders, ISSN 1471-2474, E-ISSN 1471-2474, Vol. 11, article id 222Article in journal (Refereed)
    Abstract [en]

    Background: Assessment of sensorimotor function is useful for classification and treatment evaluation of neck pain disorders. Several studies have investigated various aspects of cervical motor functions. Most of these have involved slow or self-paced movements, while few have investigated fast cervical movements. Moreover, the reliability of assessment of fast cervical axial rotation has, to our knowledge, not been evaluated before. Methods: Cervical kinematics was assessed during fast axial head rotations in 118 women with chronic nonspecific neck pain (NS) and compared to 49 healthy controls (CON). The relationship between cervical kinematics and symptoms, self-rated functioning and fear of movement was evaluated in the NS group. A sub-sample of 16 NS and 16 CON was re-tested after one week to assess the reliability of kinematic variables. Six cervical kinematic variables were calculated: peak speed, range of movement, conjunct movements and three variables related to the shape of the speed profile. Results: Together, peak speed and conjunct movements had a sensitivity of 76% and a specificity of 78% in discriminating between NS and CON, of which the major part could be attributed to peak speed (NS: 226 ± 88°/s and CON: 348 ± 92°/s, p < 0.01). Peak speed was slower in NS compared to healthy controls and even slower in NS with comorbidity of low-back pain. Associations were found between reduced peak speed and self-rated difficulties with running, performing head movements, car driving, sleeping and pain. Peak speed showed reasonably high reliability, while the reliability for conjunct movements was poor. Conclusions: Peak speed of fast cervical axial rotations is reduced in people with chronic neck pain, and even further reduced in subjects with concomitant low back pain. Fast cervical rotation test seems to be a reliable and valid tool for assessment of neck pain disorders on group level, while a rather large between subject variation and overlap between groups calls for caution in the interpretation of individual assessments.

  • 650.
    Samani, Afshin
    et al.
    Center for Sensory-Motor Interaction (SMI), Dept. of Health Science and Technology, Aalborg University.
    Mathiassen, Svend Erik
    University of Gävle, Faculty of Health and Occupational Studies, Department of Occupational and Public Health Sciences, Occupational health science. University of Gävle, Centre for Musculoskeletal Research.
    Madeleine, Pascal
    Center for Sensory-Motor Interaction (SMI), Dept. of Health Science and Technology, Aalborg University.
    Cluster-based EVA: an alternative approach for quantification of exposure variation2013In: Eighth International Conference on Prevention of Work-related Musculoskeletal Disorders; Abstracts, 2013, p. 219-Conference paper (Refereed)
10111213141516 601 - 650 of 821
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • harvard-cite-them-right
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • sv-SE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • de-DE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf