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

Abstract

To show whether a difference in fine motor control exists between patients with chronic, undiagnosed wrist pain (CUWP) and healthy controls. Furthermore, a method to assess fine motor function of the wrist is evaluated. A case-control study. The Academic Medical Center in Amsterdam, the Netherlands. Twenty-seven CUWP patients were compared with 50 healthy control subjects. Subjects performed horizontal stroke patterns on a digital writing tablet connected to a computer. The control subjects were tested twice to obtain test-retest reliability. A visual analogue scale was used to assess subjective pain. Fluency of movement and average velocity were measured. Intraclass correlation, ANOVA repeated measures statistics and Pearson correlation were calculated. There is a significant difference in fluency of motion between patients and controls, possibly due to a disturbed motor control, since there is no relationship between pain and test score, nor do CUWP patients have any abnormality in the wrist that can explain the disturbance in motor function. The test method is reliable (ICC = 0.78) and valid. The disturbed fine motor control in CUWP patients is suggested to maintain chronic wrist pain through 'strain injury, causing' pain evasive adaptation of the motor control system. This might lead to new perspectives regarding treatment of CUWP patients.