Fine motor assessment in chronic wrist pain: the role of adapted motor control

Objective: To show whether a difference in fine motor control exists betwee n patients with chronic, undiagnosed wrist pain (CUWP) and healthy controls . Furthermore, a method to assess fine motor function of the wrist is evalu ated. Design: A case-control study. Setting: The Academic Medical Center in Amsterdam, the Netherlands. Subjects: Twenty-seven CUWP patients were compared with 50 healthy control subjects. Interventions: Subjects performed horizontal stroke patterns on a digital w riting tablet connected to a computer. The control subjects were tested twi ce to obtain test-retest reliability. A visual analogue scale was used to a ssess subjective pain. Main outcome measures: Fluency of movement and average velocity were measur ed. Intraclass correlation, ANOVA repeated measures statistics and Pearson correlation were calculated. Results: There is a significant difference in fluency of motion between pat ients and controls, possibly due to a disturbed motor control, since there is no relationship between pain and lest score, nor do CUWP patients have a ny abnormality in the wrist that can explain the disturbance in motor funct ion. The test method is reliable (ICC = 0.78) and valid. Conclusions: The disturbed fine motor control in CUWP patients is suggested to maintain chronic wrist pain through 'strain injury, causing' pain evasi ve adaptation of the motor control system. This might lead to new perspecti ves regarding treatment of CUWP patients.