Auditory and visual evoked potentials in Huntington's disease.

Auditory and visual evoked potentials elicited by acoustic click (AEP) and checkerboard pattern flash (VEP) were recorded from 15 locations in 21 patients with Huntington's disease (HD) and 21 controls matched for age and sex. Peak latencies were approximately the same for both groups, except that AEP peak N100 appeared earlier in HDs. The main deviation in HDs consisted of generally reduced amplitude of VEP and AEP components; these deviations can be considered non-specific. Early VEP and AEP peaks contained no specific abnormalities comparable to those found in early somatosensory evoked potentials, as previously reported for the same subjects. VEP and AEP amplitudes were lower in medicated than in unmedicated HD patients, but amplitudes for both medicated and unmedicated HDs deviated from normal. Drugs may act to further diminish the already lower than normal amplitudes in HDs.