The development of a motor performance method for the measurement of pain

The pain caused by occupational cervicobrachial disorder (OCD) or related diseases is habitually felt in the wrist, elbow, arm or shoulder when gripping, lifting, wringing, pushing or pulling movements are made. Many patients claim to feel such pain even when diagnosis shows no organic damage, and their arm movement no irregularity. Verbal reports of such pain are considered simply a manifestation of 'feigned' illness. In order to measure such pain, a motor performance, non-verbal method was developed; the plate-pushing task. The results of the performance of this task by subjects using their 'painful' arms showed a greater and more frequent deterioration in performance than when the 'no pain' or 'weak pain' arms were used. The degree of deterioration was estimated quantitatively using Satow's model (Satow 1985 a). The deterioration measured showed that pain was actually perceived during performance. Subjects' verbal reports on the pain thus perceived described the sensory qualities of their pain, rather than the quantitative aspects. These results were supported by previous work (Taniguchi and Satow 1988).