NEUROPHYSIOLOGIC DYSFUNCTION IN HYPOMELANOSIS OF ITO - EEG AND EVOKED-POTENTIAL STUDIES

To evaluate neurological involvements in hypomelanosis of Ito (HI), we conducted electroencephalographic and evoked potential studies in 3 c hildren with HI. Patient 1 presented with the West syndrome, and was s everely handicapped. Patient 2 had mild mental retardation. Patient 3 appeared neurologically normal, but chromosome analysis showed a 46,XX /46,XX,12p + mosaic karyotype. EEGs of Patient 1 initially showed asym metric hypsarrhythmia, and later diffusely increased fast waves, occip ital dominant alpha rhythm plus multifocal spikes. Patients 2 and 3 ha d minimal and no EEG abnormalities, respectively, Brainstem auditory e voked potentials showed prolongation of wave I latency as well as I-II I and I-V interpeak latencies in Patient 1, and prolonged wave I laten cy in Patient 3. Flash visual evoked potential studies disclosed a sig nificant difference between the right and left latencies of wave IV in Patient 2. The fact that there were no specific EEG or evoked potenti al findings for HI seems to be consistent with the pathogenetically he terogeneous nature of this disorders. We emphasize the usefulness of n europhysiologic examinations in evaluating diverse CNS dysfunctions in HI patients.