White matter lucencies in multi-infarct dementia: a somatosensory evoked potentials and CT study.

White matter low attenuation (WMLA) on computed tomography (CT) and the central conduction time (CCT) measured by median nerve-somatosensory evoked potentials were examined in 12 multi-infarct dementia (MID) patients, 10 patients with multiple infarcts (MI) without dementia and 11 age-matched controls. Patients with deep vascular lesions without cortical infarcts on CT were included. In MID, prolongation of CCT and moderate to severe WMLA were observed. The CCT and WMLA in MI patients were intermediate. The CCT was longer when the WMLA was more extensive. The result suggests that white matter disease in MID is concerned to the occurrence of dementia by disturbing axonal conduction.