Evoked potentials in Huntington's disease. A comparative and longitudinal study.

Pattern-reversal visual (PRVEPs), brain-stem auditory (BAEPs), and somatosensory (SSEPs) evoked potentials were studied in 12 patients with Huntington's disease (HD) and were repeated in eight at one and two years. The mean cortical SSEP amplitude was decreased compared with that of age-matched controls, with a trend of decreasing amplitude with increasing duration and severity of illness. The SSEP latency was not significantly different from that of controls. The PRVEPs and BAEPs were normal. The serial studies showed a progressive decrease in amplitude of the SSEP over a two-year period. These neurophysiological findings may reflect the pathological involvement of the thalamus reported for HD. While evoked potentials are not of use in individual case diagnosis, the SSEP may be an objective physiological method for following the course of the disease in HD and the effects of therapeutic intervention in patient populations.