Pre- and postcentral somatosensory evoked potentials in Huntington's disease: effects of stimulus repetition rate.
We recorded frontal, central and parietal somatosensory evoked potentials (SEPs) to median nerve stimulation in 20 patients with Huntington's disease (HD) and in a group of normal controls. Two stimulus repetition rates, 1 Hz and 5 Hz, were employed. In HD patients the early cortical potentials (latency range 20-30 ms) at all 3 recording locations were replaced by a widespread, broadly configured N20-25 deflection, while later potentials at 40-80 ms did not significantly differ from those of normals. In contrast to the early P22, P27 and N30 potentials in normals, the N20-25 potential in the patients was not significantly modified by changing the stimulus repetition rate. At 40-80 ms the stimulus rate effects were similar in the patients and normals. The results show that early pre- and postcentral SEPs are both pathological in HD, while later frontal and parietal components can be totally preserved. The early N20-25 in HD is possibly a subcortical potential, seen due to unmasking in the absence of early cortical deflections.
Huttunen
J
J
Neurological Therapy Center, University of Duesseldorf, FRG.
Hömberg
V
V
Lange
H W
HW
D000328:Adult; D000368:Aged; D004558:Electric Stimulation; D005073:Evoked Potentials, Somatosensory / Q000502:physiology*; D005260:Female; D006801:Humans; D006816:Huntington Disease / Q000503:physiopathology*; D008297:Male; D008475:Median Nerve / Q000503:physiopathology; D008875:Middle Aged; D013003:Somatosensory Cortex / Q000503:physiopathology