IMPAIRMENT OF CENTRAL MOTOR CONDUCTION IN DIABETIC-PATIENTS

In 70 patients with diabetes mellitus (DM) we recorded the motor evoke d potentials (MEPs) following magnetic stimulation of the motor cortex and spinal roots. Central motor conduction time (CMCT) was determined as the difference between MEP latencies after cortical and spinal sti mulation. The mean CMCTs for the biceps, thenar and tibialis anterior muscles were prolonged in the DM group, as compared to normal controls , and 21 patients exceeded the CMCT upper confidence limit for at leas t one muscle. CMCT changes and peripheral conduction velocity abnormal ities occurred independently and were related to different clinical pa rameters. We conclude that a subclinical impairment of central motor c onduction is present in 30% of DM patients, independently from the occ urrence of a diabetic peripheral neuropathy and possibly reflecting di fferent pathophysiological mechanisms.