We aim to validate the prognostic value of quantitative EEG (QEEG) for patients who undergo mechanical thrombectomy for acute ischemic stroke.

Previous work has shown that QEEG measures, specifically the delta/alpha ratio (DAR), correlate with the severity of ischemic stroke as measured by the National Institutes of Health Stroke Scale (NIHSS) (Finnigan & van Putten 2013).  To our knowledge, this has not been validated long-term in patients with acute ischemic stroke who have undergone mechanical thrombectomy.

We collected pilot data from 24 patients (10 women, 14 men, mean age 64 years, 21 anterior circulation strokes, 3 basilar) who underwent mechanical thrombectomy at Grady Memorial Hospital (Atlanta, GA) and who also had an EEG performed during their hospital admission for other clinical indications.  Representative 3-minute clips were created from the recorded EEG.  For each patient, we calculated the difference in the delta-alpha ratio (DAR) between both hemispheres using all 16 standard bipolar channels using the Chronux toolbox (chronux.org) in MATLAB (Natick, MA). Correlations (Spearman R) were made between the inter-hemispheric DAR difference in the acute setting and the patients’ NIHSS and Modified Rankin Scale (MRS) scores upon discharge and 3 months after thrombectomy (SAS, Cary, NC).

In the 21 patients with hemispheric strokes, the hemisphere with the larger DAR correctly identified the laterality of stroke in 6 out of 6 right-sided and 11 out of 15 left-sided strokes (p=0.004, Fisher exact).  The absolute value of the inter-hemispheric DAR difference correlated with the discharge NIHSS (R=0.59, p=0.005) and MRS (R=0.53, p=0.008) and the 90-day NIHSS (R=0.6, p=0.06) and MRS (R=0.56, p=0.004) scores.

In this pilot data, the QEEG measure of delta-alpha ratio identified stroke laterality and correlated with discharge and 90-day NIHSS and MRS scores.  This preliminary data supports the prognostic value of QEEG in ischemic stroke patients who have undergone mechanical thrombectomy.