THE ABNORMALITY OF N30 SOMATOSENSORY-EVOKED POTENTIAL IN IDIOPATHIC PARKINSONS-DISEASE IS UNRELATED TO DISEASE STAGE OR CLINICAL SCORES ANDINSENSITIVE TO DOPAMINE MANIPULATIONS

We recorded short latency somatosensory evoked potentials (SEPs) to me dian nerve stimuli in 40 patients affected by idiopathic Parkinson's d isease (PD) classified from I to IV on the Hoehn and Yahr disability s cale. SEPs were recorded before and after chronic administration of L- Dopa and bromocriptine, before and after acute administration of L-Dop a. Fourteen patients experiencing wearing off and dystonic-dyskinetic disturbances were recorded during the occurrence of these oscillations of their clinical status. Absent or reduced N30 components were found in 32.5% of patients. SEPs were not modified by acute or chronic admi nistration of L-Dopa or bromocriptine or during off and dystonic or dy skinetic conditions. Multiple correlations of N30 with scores of the U nified Parkinson's Disease Rating Scale showed that N30 abnormality di d not classify patients with prominent clinical features, nor did it p redict the outcome of treatment.