Bilateral deficits in fine motor control and pinch grip force in patients with unilateral carpal tunnel syndrome.

Subjects with carpal tunnel syndrome (CTS) typically describe self-perceived pinch grip deficits, clumsiness sensations and difficulty with grasping small objects, which suggest the existence of a fine motor control deficit. No previous studies have investigated fine motor control and pinch grip force bilaterally in patients diagnosed with moderate CTS. Our aim was to investigate differences in fine motor control ability and pinch grip force between patients with unilateral CTS and healthy controls. Subtests of the Purdue Pegboard Test (one-hand, bilateral and assembly) and pinch grip force were evaluated bilaterally in 20 women with unilateral CTS (aged 22-66 years), and 20 age and hand dominance-matched healthy women. Differences between sides (affected/unaffected or dominant/non-dominant) and groups (patients or controls) were analysed with an analysis of variance (ANOVA). The ANOVA found significant differences between both groups (F = 65.7; P < 0.001) and between sides (F = 5.4; P = 0.02) for the one-hand pin placement subtest: CTS patients showed bilateral worse scores on one-hand pin placement than controls (P < 0.001). Patients also showed significantly lower scores in bilateral pin placement and assembly subtests when compared to healthy controls (P < 0.001). The ANOVA also revealed significant differences between groups (F = 141.2; P < 0.001), and fingers (F = 142.2; P < 0.001), but not between sides (F = 0.9; P = 0.4) for pinch grip strength: CTS patients showed bilateral lower pinch grip force levels in all fingers when compared to controls (P < 0.001). Fine motor control and pinch grip were negatively related to the hand pain intensity and duration of symptoms history (all, P < 0.01). Our findings revealed bilateral deficits in fine motor control ability and pinch grip force in patients with unilateral moderate CTS when compared to controls.