EEG as predictor of dementia following first ischemic stroke

Predictive factors for occurrence of vascular dementia may help identify patients at increased risk of developing this condition. Our purpose was to evaluate the prognostic value of early EEG findings in patients after first ischemic cerebral stroke on the development of dementia.

We performed routine EEG recordings in 199 consecutive non-demented patients with first-ever ischemic stroke, within 48 h of the event. The patients were subsequently followed for their mental state for 2 years. Survival analysis, wherein onset of dementia was the end-point, was performed on the total sample population and conducted separately on those who had normal EEG at time of the event and on those who had abnormal EEG findings (focal or diffuse slowing).

Patients with abnormal EEG at baseline had 2.6 times the risk of developing dementia than those who had normal EEG; this odds ratio was statistical significant (CL: 1.3-5.1, p = 0.003). Development of dementia was not related to any specific EEG abnormal pattern.

Abnormal EEG performed close to the first ischemic stroke appears to be an indicator of subsequent cognitive decline, probably because it indicates cortical involvement by the stroke or an underlying indolent cerebral degeneration.