title: Cognitive performance and muscle activation in workers with chronic shoulder myalgia.
abstract: The present study determined whether workers with chronic shoulder myalgia exhibit impaired cognitive performance and elevated muscle activation. Ten workers with and 10 without shoulder myalgia performed three sessions, each consisting of three different cognitive tasks. Subjective pain was reported on visual analogue scales (VAS). Surface electromyography was recorded bilaterally from the trapezius and forearm extensor muscles. Speed and error rates of the cognitive work were almost the same in the two groups, but the myalgia subjects reported more stress during the work. In two of the cognitive tasks, both groups increased their speed of performance to the same extent from the first to the third session, despite pain increase in the myalgia subjects. In the biomechanically demanding task, the speed fell from the first to the third session in both groups. Muscle activation was equal in the two groups and constant throughout the protocol despite changes in speed of performance and pain. It is concluded that localized chronic muscle pain does not significantly alter cognitive performance, or muscle activation level during cognitive work. However, the perceived burden of work is larger, as indicated by the higher stress reported during cognitive work in the myalgia subjects compared with their pain-free controls.
authors.affiliation: Department of Physiology, National Institute of Occupational Health, University of Oslo, Norway. cecilie.roe@stami.no
authors.forename: C
authors.initials: C
authors.lastname: Røe
authors.forename: R A
authors.initials: RA
authors.lastname: Bjørklund
authors.forename: S
authors.initials: S
authors.lastname: Knardahl
authors.forename: M
authors.initials: M
authors.lastname: Waersted
authors.forename: N K
authors.initials: NK
authors.lastname: Vøllestad
mesh_terms: D002908:Chronic Disease; D003071:Cognition; D004576:Electromyography; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000503:physiopathology*; D009784:Occupational Diseases / Q000503:physiopathology*; D016272:Occupational Health; D020069:Shoulder Pain / Q000503:physiopathology*; D013647:Task Performance and Analysis