Is median nerve enlargement at the wrist associated with tremor in Parkinson disease?

OBJECTIVES Tremor is one of the cardinal features of Parkinson disease (PD) and may cause cumulative trauma-related injury to nerves of the hands. The aim of this study was to assess the electrodiagnostic and sonographic features of patients with PD and to assess the effect of tremor in PD on the median nerve. METHODS We studied 31 hands of healthy control participants (n = 16; mean age ± SD, 60.25 ± 14.67 years) and 81 hands of patients with PD (n = 42; 64.95 ± 11.13 years). Motor symptoms were measured by the Unified Parkinson's Disease Rating Scale III. Median nerve conduction studies and sonographic cross-sectional area measurements were performed in all participants. RESULTS The median nerve cross-sectional area in patients with PD (10.71 ± 2.79 mm(2)) was significantly larger than that in the control group (7.40 ± 1.05 mm(2); P < .05). However, there was no significant difference in median nerve electrodiagnostic findings between the PD and control groups. The median nerve cross-sectional area was associated with the severity of the tremor but not with the Unified Parkinson's Disease Rating Scale motor score. CONCLUSIONS Tremor in PD is associated with median nerve enlargement but not with impairment of median nerve conduction.