Intermuscular coherence in Parkinson's disease: relationship to bradykinesia

We hypothesised that bradykinesia may be partly due to the failure of the c orticomuscular system to engage in high frequency oscillatory activity in P arkinson's disease (PD). In healthy subjects such oscillations are evident in coherence between active muscles at 15-30Hz. We therefore investigated t he effects of therapeutic stimulation of the basal ganglia on this coherenc e and related it to changes in bradykinesia in the contralateral arm. Incre ases in coherence at 15-30 Hz and improvements in bradykinesia upon stimula tion were correlated (r = 0.564, p < 0.001). This suggests that the basal g anglia modulate oscillatory activity in the corticomuscular system and that impairment of the motor system's ability to engage in synchronised oscilla tions at high frequency may contribute to bradykinesia in PD. NeuroReport 1 2:2577-2581 (C) 2001 Lippincott Williams & Wilkins.