Performance of repetitive alternating elbow movements in Parkinson's disease.

ABSTRACT

BACKGROUND: Bradydiadochokinesia is one main clinical symptom in idiopathic Parkinson's disease (IPD). The pathogenesis of bradydiadochokinesia is not completely clear. METHODS: Fifteen patients with IPD and 15 age-matched healthy volunteers had to perform rhythmic alternating flexion and extension movements in the elbow joint. The rhythm was provided auditorily by a click tone stimulator. Six maneuvers (spatial extents of 48 and 83° at frequencies of 0.45, 0.75 and 1.25 Hz) had to be absolved. The potentiometer converted the horizontal forearm movements into a variable voltage. RESULTS: The duration of single movements varied more significantly in patients than in controls (p < 0.05; Mann-Whitney U test). Patients executed all conditions more slowly than controls, but this difference was only significant at the most difficult condition (83° at 1.25 Hz; p < 0.01). The movement amplitudes or their variability were not significantly different at any condition. No parameter correlated significantly with the motor part of the Unified Parkinson's Disease Rating Scale (UPDRS) or with the duration of disease. CONCLUSION: An insufficient temporal coordination contributes to bradydiadochokinesia in IPD. This deficit occurs independently of other parkinsonian cardinal motor symptoms.