Central motor conduction time in Parkinson's disease

Central motor conduction time (CMCT) was analysed in 11 patients with Parkinson's disease and 10 age matched healthy controls. CMCT was measured during muscle relaxation, muscle contraction and in patients with Parkinson's disease before and 1 h after intravenous infusion of L-dopa (0.25%, 20 ml). Although the CMCT during muscle contraction did not differ significantly between Parkinson's disease and healthy controls, the CMCT during muscle relaxation was significantly shorter in Parkinson's disease than in healthy controls. The CMCT during muscle relaxation in Parkinson's disease was significantly longer after intravenous infusion of L-dopa than before, but the CMCT during muscle contraction did not differ significantly before and after intravenous infusion of L-dopa. The CMCT during muscle contraction was significantly shorter than the CMCT during muscle relaxation in healthy controls. However, in Parkinson's disease, the CMCT did not differ significantly between muscle relaxation and contraction. We consider that the central motor conduction pathway during muscle relaxation in Parkinson's disease is modified to be similar to that during muscle contraction in healthy subjects. Copyright 1999 Harcourt Publishers Ltd.