Central motor conduction time in Parkinson's disease

Central motor conduction time (CMCT) was analysed in 11 patients with Parki nson's disease and 10 age matched healthy controls. CMCT was measured durin g muscle relaxation, muscle contraction and in patients with Parkinson's di sease before and 1 h after intravenous infusion of t-dopa (0.25%, 20 ml). A lthough the CMCT during muscle contraction did not differ significantly bet ween Parkinson's disease and healthy controls, the CMCT during muscle relax ation was significantly shorter in Parkinson's disease than in healthy cont rols. The CMCT during muscle relaxation in Parkinson's disease was signific antly longer after intravenous infusion of L-dopa than before, but the CMCT during muscle contraction did not differ significantly before and after in travenous infusion of L-dopa. The CMCT during muscle contraction was signif icantly shorter than the CMCT during muscle relaxation in healthy controls. However, in Parkinson's disease, the CMCT did not differ significantly bet ween muscle relaxation and contraction. We consider that the central motor conduction pathway during muscle relaxation in Parkinson's disease is modif ied to be similar to that during muscle contraction in healthy subjects.