Multi-modal evoked potentials in corticobasal degeneration, progressive supranuclear palsy and Alzheimer disease

Short-latency somatosensory evoked potentials (SSEPs), auditory event-related potentials (ERPs), brainstem auditory evoked potentials (BAEPs) and visual evoked potentials (VEPs) were studied in 8 patients with corticobasal degeneration (CBD), 4 patients with progressive supranuclear palsy (PSP), 15 patients with Alzheimer disease (AD) and 15 normal control subjects. All patient groups showed significant prolongations of N200 and P300 latencies of ERPs compared with the normal controls. Patients with CBD showed significant prolongation of the interpeak latency between N13 and N20 (N13-N20) of SSEPs compared with the normal controls. In addition, CCT elicited by stimulation of the more affected side showed significant prolongation compared to CCT following stimulation of the less affected side. There were no significant differences in interpeak latencies between waves I and V of BAEP and P100 latency of VEPs among these four groups. The present results show that patients with CBD have different electrophysiological features, which may be useful for the differential diagnosis between CBD and PSP or AD.