Evoked potentials in patients with Huntington's disease and their offspring. II. Visual evoked potentials

Visual evoked potentials (VEPs) to full-field and half-field stimulation were recorded in a large sample of patients with Huntington's disease (n = 36) and subjects at risk (first-order offspring, n = 55) using a checkerboard pattern reversal stimulus. Whereas a clear diminution of the amplitudes found confirmed earlier findings in patients with Huntington's disease, further alterations of VEP wave forms consisted in the absence of asymmetric hemisphere lateralization to half-field stimulation (i) and severe distortion with amplification of the early NPN/PNP complexes (ii). Considering at least two different abnormal parameters necessary to represent a reliable indicator of the disease, 24 patients (67%) and 14 (25%) of the persons at risk exhibited pathological results. In contrast, only 2 among 36 patients (5%) but 30 (55%) among the offspring exhibited normal results. The diagnostic and predictive value of the investigation of VEPs in Huntington's disease is discussed.