Neuromuscular and psychological characteristics in subjects with work-related forearm pain

There are scant data available on the neuromuscular and psychological characteristics of patients with cumulative trauma disorders. We compared 16 subjects with work-related forearm and hand pain in the dominant upper limb with 9 age-matched control subjects. Pain subjects were divided into two groups based on nerve conduction studies: eight subjects were in the study group for median neuropathy at the wrist (MN, median transcarpal latency >2.3 ms), and eight were in the study group for electrodiagnostically negative pain (EN). Average pain, forearm muscle tenderness, grip strength, pinch strength, and wrist flexor and extensor strength were measured. The Health Status Questionnaire and the Beck Depression Inventory were used to measure health perception and depressive symptoms, respectively. Work satisfaction was determined by a newly devised scale. Statistical analysis was by analysis of variance and planned comparison analysis. The MN and EN groups did not significantly differ on any of the measures except median transcarpal latency. Both pain groups had significantly (P < 0.05) greater average pain, greater extensor muscle tenderness, higher Beck Depression Inventory scores, higher pain rating, and poorer physical functioning on the Health Status Questionnaire than did the normal control group. Grip strength and wrist extension force were diminished in both cumulative trauma groups compared with control subjects; however, only grip strength in the MN group and wrist extension force in the EN group differed significantly (P < 0.05) from control subjects. Only the EN group had significantly less work satisfaction than did the control group. Overall, both pain groups differed from control subjects and shared similar characteristics, with the exception of median neuropathy.