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Elcadi, Guilherme H.ORCID iD iconorcid.org/0000-0001-5005-9957
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Publications (10 of 20) Show all publications
Richter, H., Domkin, D., Elcadi, G. H., Andersson, H. W., Högberg, H. & Englund, M. (2019). A Comparison of Mental and Visual Load Resulting from Semi-automated and Conventional Forest Forwarding: An Experimental Machine Simulation Study (827ed.). In: Sebastiano Bagnara Riccardo Tartaglia · Sara Albolino Thomas Alexander · Yushi Fujita (Ed.), Bagnara S., Tartaglia R., Albolino S., Alexander T., Fujita Y. (Ed.), Proceedings of the 20th Congress of the International Ergonomics Association (IEA 2018): Volume X: Auditory and Vocal Ergonomics, Visual Ergonomics, Psychophysiology in Ergonomics, Ergonomics in Advanced Imaging. Paper presented at 20th Congress of the International Ergonomics Association, IEA 2018, 26-30 August 2018, Florence, Italy (pp. 199-208). Cham, X
Open this publication in new window or tab >>A Comparison of Mental and Visual Load Resulting from Semi-automated and Conventional Forest Forwarding: An Experimental Machine Simulation Study
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2019 (English)In: Proceedings of the 20th Congress of the International Ergonomics Association (IEA 2018): Volume X: Auditory and Vocal Ergonomics, Visual Ergonomics, Psychophysiology in Ergonomics, Ergonomics in Advanced Imaging / [ed] Bagnara S., Tartaglia R., Albolino S., Alexander T., Fujita Y., Cham, 2019, 827, Vol. X, p. 199-208Conference paper, Published paper (Refereed)
Abstract [en]

The purpose of the present study was to extend the knowledge offunctional linkages between visual and mental load, performance, and prefrontalcortex (PFC) activity, during forestry forwarding 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 machinesimulator during two counterbalanced test conditions: (i) conventional cranecontrol, and; (ii) semi-automated crane control. Mental load was assessed byquantification of oxygenated hemoglobin (HbO2) concentration changes overthe right dorsolateral prefrontal cortex (dlPFC) via non-invasive functional nearinfrared spectrometry (fNIRS). Visual, autonomic, and motoric control variableswere measured and analyzed in parallel along with the individual level of performance.Linear Mixed Models (LMM) analysis indicated more mental loadduring conventional crane work. Collectively, our data suggest that fNIRS is aviable tool which can be used in neuroergonomic research to evaluate physiologicalactivity levels in PFC.

Place, publisher, year, edition, pages
Cham: , 2019 Edition: 827
Series
Advances in Intelligent Systems and Computing, ISSN 21945357, E-ISSN 2194-5365 ; 827
Keywords
Visual ergonomics, neuroergonomics, Nirs, robotics
National Category
Other Medical Sciences
Identifiers
urn:nbn:se:hig:diva-27848 (URN)10.1007/978-3-319-96059-3_22 (DOI)2-s2.0-85051781837 (Scopus ID)978-3-319-96058-6 (ISBN)978-3-319-96059-3 (ISBN)
Conference
20th Congress of the International Ergonomics Association, IEA 2018, 26-30 August 2018, Florence, Italy
Funder
Forte, Swedish Research Council for Health, Working Life and Welfare, 2009-1761
Note

Södra Skogsägarnas Stiftelse för Forskning, Utveckling och Utbildning Grant no: 2009-1761

Available from: 2018-09-05 Created: 2018-09-05 Last updated: 2018-12-05Bibliographically approved
Richter, H., Domkin, D., Elcadi, G. H., Anderson, H. W., Högberg, H. & Englund, M. (2018). A comparison of mental and visual loads resulting from semi-automated and conventional forest harvesting: An experimental machine simulation study. In: : . Paper presented at IEA 2018 - 20th Congress International Ergonomics Association - Florence, 26th - 30th August 2018, Florence, Italy.
Open this publication in new window or tab >>A comparison of mental and visual loads resulting from semi-automated and conventional forest harvesting: An experimental machine simulation study
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2018 (English)Conference paper, Oral presentation only (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.

National Category
Medical and Health Sciences
Identifiers
urn:nbn:se:hig:diva-25769 (URN)
Conference
IEA 2018 - 20th Congress International Ergonomics Association - Florence, 26th - 30th August 2018, Florence, Italy
Projects
Skogsmaskinförares mentala och fysiska belastningsnivåer under arbete med delautomatiserad skotarkran – en experimentell studie i skogsmaskinsimulator (MentAuto)
Note

Abstract submitted to: IEA 2018 - 20th Congress International Ergonomics Association - Florence, 26th - 30th August 2018

Available from: 2017-12-08 Created: 2017-12-08 Last updated: 2018-03-22Bibliographically approved
Richter, H., Domkin, D., Elcadi, G. H., Andersson, H., Högberg, H., Forsman, M. & Englund, M. (2018). A comparsion of mental and visual loads resulting from semi-automated and conventional forest harvesting: An experimental machine simulation study. In: Per Lindberg (Ed.), FALF Konferens 2018: Arbetet - problem eller potential för en hållbar livsmiljö?: Program och Abstracts. Paper presented at FALF KONFERENS 2018 'Arbetet - problem eller potential för en hållbar livsmiljö?',10-12 juni 2018, Gävle (pp. 96). Gävle: Gävle Universtiy Press
Open this publication in new window or tab >>A comparsion of mental and visual loads resulting from semi-automated and conventional forest harvesting: An experimental machine simulation study
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2018 (English)In: 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, Oral presentation with published abstract (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.

Place, publisher, year, edition, pages
Gävle: Gävle Universtiy Press, 2018
National Category
Medical and Health Sciences Health Sciences
Identifiers
urn:nbn:se:hig:diva-27224 (URN)978-91-88145-28-4 (ISBN)
Conference
FALF KONFERENS 2018 'Arbetet - problem eller potential för en hållbar livsmiljö?',10-12 juni 2018, Gävle
Projects
MentAuto
Available from: 2018-06-20 Created: 2018-06-20 Last updated: 2018-12-06Bibliographically approved
Blomqvist, S., Ervasti, P.-E. & Elcadi, G. H. (2018). Evaluating physical workload by position during match in elite bandy. Journal of Strength and Conditioning Research, 32(9), 2616-2622
Open this publication in new window or tab >>Evaluating physical workload by position during match in elite bandy
2018 (English)In: Journal of Strength and Conditioning Research, ISSN 1064-8011, E-ISSN 1533-4287, Vol. 32, no 9, p. 2616-2622Article in journal (Refereed) Published
Abstract [en]

To improve current understandings of physical Workload (WL) in elite Bandy, ten bandy players were monitored for heart rate (HR) during thirteen matches over one championship season. Participants were divided into five subgroups according to playing position - libero, defender, halves, midfielder and forward. HR measurements were analyzed with two different methods to compute physical WL - (i) percentage of total time spent in different HR zones (HRres) and (ii) WL based on the Edwards method. Also determined was the time spent at HR levels above the lactate threshold (LT). A one-way ANOVA was used for analysis. For WL according to the Edwards method, significant differences (p=0.05) were shown between groups with defenders presenting the highest scores and forwards and liberos the lowest. A significant difference (p=0.05) was found between liberos and halves and the other positions as to how much time they spent in zone 70-80% of HRres. In 91-100% of HRres there was a distinct difference between defenders and the other positions and also forwards differed significantly from liberos, defenders and halves (p=0.05). The libero spent only one percent of the time over the LT, whereas the midfielder spent about 27% of the time over the LT. Overall, defenders showed the greatest WL during a match and liberos the lowest. The practical implications of these findings can help coaches and trainers design training methods specific to each position as well as individualized training sessions for each player in elite bandy.

National Category
Sport and Fitness Sciences
Identifiers
urn:nbn:se:hig:diva-26388 (URN)10.1519/JSC.0000000000002551 (DOI)000454031400027 ()29489729 (PubMedID)2-s2.0-85056289580 (Scopus ID)
Available from: 2018-04-03 Created: 2018-04-03 Last updated: 2019-01-07Bibliographically approved
Sandberg, C., Crenshaw, A. G., Elcadi, G. H., Christensen, C., Hlebowicz, J., Thilén, U. & Johansson, B. (2018). Impaired skeletal muscle endurance in adults with complex congenital heart disease is associated with local muscle oxygenation. International Journal of Cardiology
Open this publication in new window or tab >>Impaired skeletal muscle endurance in adults with complex congenital heart disease is associated with local muscle oxygenation
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2018 (English)In: International Journal of Cardiology, ISSN 0167-5273, E-ISSN 1874-1754Article in journal (Refereed) Submitted
Keywords
Congenital heart disease, Muscle function, Muscle endurance, Muscle oxygenation, near-infrared spectroscopy
National Category
Cardiac and Cardiovascular Systems
Identifiers
urn:nbn:se:hig:diva-27641 (URN)
Available from: 2018-08-14 Created: 2018-08-14 Last updated: 2018-09-04Bibliographically approved
Richter, H., Forsman, M., Elcadi, G. H., Brautaset, R., Marsh, J. E. & Zetterberg, C. (2018). 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 fatigue. Frontiers in Human Neuroscience, 12, Article ID 298.
Open this publication in new window or tab >>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 fatigue
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2018 (English)In: Frontiers in Human Neuroscience, ISSN 1662-5161, E-ISSN 1662-5161, Vol. 12, article id 298Article in journal (Refereed) Published
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.

Place, publisher, year, edition, pages
Frontiers Media S.A., 2018
Keywords
Visual fatigue, Accommodation, Compensatory effort, Convergence, Disparity, Near Infrared Spectroscopy (NIRS), Time series analysis, Visual ergonomics
National Category
Occupational Health and Environmental Health
Identifiers
urn:nbn:se:hig:diva-25766 (URN)10.3389/fnhum.2018.00298 (DOI)000440216100002 ()30104967 (PubMedID)2-s2.0-85054772976 (Scopus ID)
Funder
Forte, Swedish Research Council for Health, Working Life and Welfare, 2009-1761Swedish Research Council, 2015-01116
Note

Corrigendum: Prefrontal Cortex Oxygenation Evoked by Convergence Load Under Conflicting Stimulus-to-Accommodation and Stimulus-to-Vergence Eye-Movements Measured by NIRS DOI: 10.3389/fnhum.2018.00384.

ScopusId: 2-s2.0-85054817559

ISI-id: 000445088000001

Available from: 2017-12-08 Created: 2017-12-08 Last updated: 2019-03-12Bibliographically approved
Kotsa, K., Elcadi, G. H., Grammatiki, M., Xergia, S., Catrina, S. B. & Tsaklis, P. (2017). Dorsolateral prefrontal cortex activity towards fatigue of type 2 diabetes patients with macro-angiopathy and peripheral neuropathy (pilot study). Paper presented at 53rd Annual Meeting of the European Association for the Study of Diabetes (EASD), 11-15 September, 2017, Lisbon, Portugal. Diabetologia, 60, S446-S447
Open this publication in new window or tab >>Dorsolateral prefrontal cortex activity towards fatigue of type 2 diabetes patients with macro-angiopathy and peripheral neuropathy (pilot study)
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2017 (English)In: Diabetologia, ISSN 0012-186X, E-ISSN 1432-0428, Vol. 60, p. S446-S447Article in journal, Meeting abstract (Other academic) Published
National Category
Endocrinology and Diabetes
Identifiers
urn:nbn:se:hig:diva-25744 (URN)000408315003080 ()
Conference
53rd Annual Meeting of the European Association for the Study of Diabetes (EASD), 11-15 September, 2017, Lisbon, Portugal
Available from: 2017-12-06 Created: 2017-12-06 Last updated: 2018-03-13Bibliographically approved
Elcadi, G. H., Tsaklis, P., Blomqvist, S., Ervasti, P.-E., W. Söderström, M., Forsman, M. & Richter, H. (2016). A Strong Correlation Between Dorsolateral Prefrontal Cortex And Vastus Lateralis Activity During Running To Fatigue. Paper presented at Annual Meeting of the American-College-of-Sports-Medicine (ACSM), 31 May - 4 June 2017, Boston, MA, USA. Medicine and science in sports and exercise, 48(5), 854-854
Open this publication in new window or tab >>A Strong Correlation Between Dorsolateral Prefrontal Cortex And Vastus Lateralis Activity During Running To Fatigue
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2016 (English)In: Medicine and science in sports and exercise, ISSN 0195-9131, Vol. 48, no 5, p. 854-854Article in journal, Meeting abstract (Refereed) Published
Abstract [en]

Fatigue is a phenomenon of pronounced importance in sports. Recently, there is strong evidence of interplay between the prefrontal cortex and motor output during fatiguing contractions. The dorsolateral prefrontal cortex (DLPC) due to its large involvement in cognitive and motor activities is believed to be involved but this requires physiological clarification. AIM: We investigated the relationship between DLPC activity - responses in oxyhemoglobin (HbO2) and total hemoglobin (HbT) measured by near-infrared spectroscopy (NIRS), and the vastus lateralis muscle (VL) activity - quantified as root-mean-square (RMS) of the EMG signal, during a fatigue protocol.

METHODS: Four male runners (32±12 yrs) with probes for NIRS over the DLPC and EMG over the VL performed a track running test at a constant speed to fatigue (exhaustion). The running speed was individually determined as the average speed of a 1200-m time trial performed ~3 days prior to testing. For NIRS changes in μmole/L of HbO2 and HbT were computed. The VL EMG-RMS of the contraction of each step was normalized as a percent of a submaximal reference contraction (%RMS), thus removing the non-activity between steps. Data of 10s epochs at 20, 40, 60, 80 and 100% of time for each lap were averaged for analyses. Regression analyses performed with HbO2 and with HbT as dependent variables and %RMS as the independent variable.

RESULTS: Over time there was an increase in HbO2 and HbT in the DLPC, and in VL-%RMS. Both HbO2 and HbT correlated strongly with EMG-RMS during running to fatigue (see figures below); p<0.001 for both.

CONCLUSION: The strong relationship between DLPC and VL activities during running to fatigue suggests the involvement of the DLPC in the central processing of fatigue.

National Category
Sport and Fitness Sciences Applied Psychology
Identifiers
urn:nbn:se:hig:diva-22135 (URN)10.1249/01.mss.0000487560.58653.96 (DOI)000415211700135 ()
Conference
Annual Meeting of the American-College-of-Sports-Medicine (ACSM), 31 May - 4 June 2017, Boston, MA, USA
Available from: 2016-07-08 Created: 2016-07-08 Last updated: 2018-12-03Bibliographically approved
Richter, H., Crenshaw, A. G., Domkin, D. & Elcadi, G. H. (2016). Near infrared spectroscopy as a useful research tool to measure prefrontal cortex activity during visually demanding near work. IIE Transactions on Occupational Ergonomics and Human Factors, 4(2-3), 164-174
Open this publication in new window or tab >>Near infrared spectroscopy as a useful research tool to measure prefrontal cortex activity during visually demanding near work
2016 (English)In: IIE Transactions on Occupational Ergonomics and Human Factors, ISSN ISSN 2157-7323, Vol. 4, no 2-3, p. 164-174Article in journal (Refereed) Published
Abstract [en]

Background: Unlike the usual skeletal muscles, ciliary muscles responsible for focusing the crystalline eye lens and extraocular muscles responsible for convergence eye movements appear resistant to fatigue. Purpose: The dual goals of this article are to briefly outline the current evidence that suggests that probing into blood flow and hemodynamic prefrontal brain activity with Near-Infrared Spectroscopy (fNIRS) could advance progress in visual ergonomic research, and to provide pilot data exemplifying the proposed approach. Methods: The vision task consisted of sustained focusing on a contrast-varying black and white Gabor grating. Four participants with a median age of 46 (IQR 44 – 50) fixated the grating from a distance of 65 cm. Three counterbalanced 10-min tasks required central fixation and accommodation/convergence on the grating target through: (i) 0.0 diopter (D) lenses, (ii) −1.5 D lenses, and (iii) −3.5yD lenses while maintaining maximal focus. Non-invasive measurements of local oxyhemoglobin (HbO2) were quantified with a one-channel Near Infrared Spectrometer, NIRS. The NIRS probe was placed on the prefrontal cortex in the vicinity of the right dorsolateral prefrontal cortex or Brodmann area 46 (DLPFC, BA 46). Accommodation response and contrast threshold was measured in parallel. Results: General estimating equation analyses showed that baseline subtracted DLPFC blood flow (ΔHbO2) increased significantly over time in all three lens conditions. The effect of time may be caused by a continuous increase in mental effort to compensate for progressively more mental fatigue induced by increased visual attention. The increase of DLPFC ΔHbO2 was also larger in magnitude in participants with larger amplitudes accommodation response (i.e., in participants who minimized deterioration in visual performance). Conclusion: The results from this study indicate that oxyhemoglobin changes recorded over DLPFC with NIRS can be used to assay the degree to which the visual system is strained during demanding near work.

Keywords
Attention fatigue, Accommodation, Compensatory effort, Discomfort, Electromyography, Mental fatigue, Near-Infrared Spectroscopy, Neck pain, Productivity, Visual ergonomics
National Category
Health Sciences
Identifiers
urn:nbn:se:hig:diva-18657 (URN)10.1080/21577323.2015.1067258 (DOI)000442406000008 ()
Funder
Forte, Swedish Research Council for Health, Working Life and Welfare, 2009-1761
Note

Accepted author version posted online.

Available from: 2015-01-01 Created: 2015-01-01 Last updated: 2018-12-06Bibliographically approved
Gold, J. E., Lewis, C., Mathiassen, S. E. & Elcadi, G. H. (2016). Trapezius oxygenation and hemodynamics during work : a field study using EMG and Near Infrared Spectroscopy (NIRS). In: : . Paper presented at Ninth International Conference on the Prevention of Work-Related Musculoskeletal Disorders (PREMUS), June 20-23, 2016, Toronto, Canada.
Open this publication in new window or tab >>Trapezius oxygenation and hemodynamics during work : a field study using EMG and Near Infrared Spectroscopy (NIRS)
2016 (English)Conference paper, Published paper (Refereed)
Abstract [en]

Background. Relative blood volume (RBV) and muscle oxygenation (TSI) can be measured using near infrared spectroscopy (NIRS), but no studies have used NIRS with workers performing their job in the field. The study aims were (1) to assess day-to-day within-subjects dispersion in NIRS measurements during work, and (2) to determine whether trapezius RBV and TSI differed between office and industrial workers. Electromyography (EMG) measured trapezius muscle activity.

Methods. Portable NIRS and EMG instruments were adhered to the trapezius of healthy female industrial (n = 8) and office (n = 10) workers for approximately four hours on two separate days. Mean and standard deviation (SD) RBV, TSI and 50th percentile EMG were calculated for both days separately. Participants were videotaped to demarcate work and rest periods, and to qualitatively assess ergonomic exposures. Two-way mixed effects models were constructed to examine outcomes, with occupation (office/industrial) and work/rest as fixed effects and subject as a random effect.

Results. Industrial workers appeared to have more variable arm postures and handled heavier loads than office workers. The between-days variability of RBV and TSI indicated that NIRS performed well in an occupational setting. Median trapezius EMG showed an effect of occupation (p < 0.0001), and an interaction between occupation and work/rest (p < 0.0001). As expected, industrial workers had higher median EMG overall and during work, but office workers had a higher EMG during rest. Similar results for EMG SD were found. Mean RBV and RBV SD were greater in industrial workers. No effects on mean TSI were found. However, TSI SD was higher in industrial workers, while TSI SD was greater in office workers during rest.

Discussion. NIRS had a satisfying reliability and showed face validity with respect to expected responses to occupational work. NIRS shows promise as a method for measuring hemodynamics in the field.

Keywords
near infrared spectroscopy, trapezius muscle, trapezius muscle activity, occupational work
National Category
Occupational Health and Environmental Health
Identifiers
urn:nbn:se:hig:diva-21914 (URN)
Conference
Ninth International Conference on the Prevention of Work-Related Musculoskeletal Disorders (PREMUS), June 20-23, 2016, Toronto, Canada
Available from: 2016-06-23 Created: 2016-06-23 Last updated: 2018-12-03Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0001-5005-9957

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