Additional Value of Quantitative EEG in Ischemic Stroke

Stroke is among the leading causes for adult-onset disability and death worldwide, carrying an enormous psycho-social burden and a significant impact on health resources.;The general aim of this PhD work was to evaluate the additional value of quantitative electro-encephalography (EEG) in ischemic stroke with regard to clinically relevant state and outcome measures. An essentially pragmatic design was specifically implemented to extrapolate our findings directly to routine clinical practice with limited resources.;In a methodological analysis, we found a high level of intra-record, intra-rater and inter-rater reproducibility of quantitative EEG spectral parameters. We introduce the single channel pair averaged revised spatial Brain Symmetry Index (pdBSI) which evaluates asymmetry along homologous channel pairs. In acute anterior circulation syndrome of presumed ischemic origin, pdBSI emerged as the only independent predictor for radiologically confirmed stroke and early neurological deterioration while spontaneous early neurological improvement was independently predicted by the (delta + theta / alpha + beta) -- ratio (DTABR) and volume of recent infarction.;In patients presenting with a lacunar (LACS) or posterior circulation syndrome (POCS), definite stroke was independently predicted by pdBSI, even in patients without neurological deficits at the time of EEG recording. Unfavourable outcome at day 7 was predicted by DTABR in LACS but not in POCS.;The National Institute of Health Stroke Scale (NIHSS) score and pdBSI emerged as statistically significant independent predictors for disability six months after ischemic stroke. Dependency six months after ischemic stroke was independently predicted by NIHSS and DTABR.;Age at stroke onset, NIHSS and DTABR emerged as statistically significant independent predictors for death six months after ischemic stroke.;Our findings suggest that EEG monitoring in the acute and subacute phase may be useful in all ischemic stroke types regardless of localisation, OCSP classification, previous stroke, or use of psychotropic medication.;Based on its superior predictive value for short-term and long-term outcome, its versatility and relative inexpensiveness, early quantitative EEG might be considered a routine evaluation tool in the assessment of patients presenting with ischemic stroke.