The origin and afferentation of the frontal N30 component of the median nerve somatosensory evoked potentials (SEPs) have not yet been fully elucidated. The aim of this study was to assess the possible selective impairment of the N30 component in patients with lacunar infarcts of the basal ganglia as compared to patients with lacunar infarctions sparing the basal ganglia and to a group of healthy subjects. Median nerve SEPs were measured in ten patients with lacunar infarctions of the brain

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... no cortical atrophy or leukoaraiosis) and 13 healthy volunteers. Four patients had lacunar infarctions affecting the basal ganglia and 6 patients had lesions affecting other structures. In two patients with lesions affecting the head of the caudate nucleus, there was no identifiable N30 component on the affected side. In one patient with bilateral lesions of the globus pallidus, the amplitude of the N30 component was significantly reduced. In one patient with lesion of the tail of the caudate nucleus, the N30 component was unaffected. The amplitude of the N30 component was also reduced in two patients with frontal subcortical white matter lesions. In all the other subjects, we recorded normal N30 components on both sides. Our results further support the importance of the basal ganglia, especially the head of the caudate nucleus in the generation of the N30 component of the median nerve SEPs.