Motor cortex hyperexcitability in subcortical ischemic vascular dementia.

To study whether in subcortical ischemic vascular dementia (SIVD) the changes of motor cortex excitability are due to the dementing process or to the cerebrovascular lesions, we examined 20 SIVD patients, 20 patients with subcortical ischemic disease without dementia (SIDWD) and 20 control subjects who underwent transcranial magnetic stimulation (TMS). Motor threshold (MT), amplitudes of motor evoked potentials (MEPs) and silent period (SP) were considered. MT in SIVD patients (32.7 ± 2.6%) was significantly lower (p<0.001) than in SIDWD patients (47.9 ± 3.4%) and in controls (49.1 ± 4.2%). MEP amplitude was larger in SIVD patients (6.8 ± 1.7 mV) than in the other groups (5.7 ± 1.9 mV and 5.2 ± 1.8 mV, p<0.02). Motor cortex excitability is enhanced in SIVD. Our data, taken together with previous results in Alzheimer disease (AD), indicate that motor cortex hyperexcitability is a common finding in different dementing illnesses.