ABSTRACT NUMBER: ESOC2026LB195 PROGNOSTIC ROLE OF AWAKE AND SLEEP EEG AFTER ISCHEMIC STROKEPROGNOSTIC ROLE OF AWAKE AND SLEEP EEG AFTER ISCHEMIC STROKE

Abstract Background and aims Electroencephalography (EEG) reflects functional cortical impairment following acute ischemic stroke and may provide prognostic information beyond clinical assessment. Sleep-related cortical synchronization may enhance the sensitivity of EEG in detecting post-stroke abnormalities; however, the comparative prognostic value of awake and sleep EEG remains insufficiently defined. To evaluate the prognostic significance of awake and sleep EEG findings in acute ischemic stroke and their association with 3-month functional outcome. Methods In this prospective single-center study, 48 patients with first-ever acute ischemic stroke underwent a 20–30-minute awake EEG followed by a 60-minute sleep EEG within 3–5 days of stroke onset. EEG abnormalities included diffuse slowing, focal delta activity, and epileptiform discharges. Stroke severity was assessed using NIHSS at admission. Functional outcome at 3 months was evaluated using the modified Rankin Scale (mRS) and categorized as favorable (0–2) or unfavorable (3–6). Results EEG abnormalities were detected in 60.4% of patients during awake recording and in 79.1% during sleep EEG. Diffuse slowing was more frequent in patients with higher baseline NIHSS scores. At 3 months, 56.2% achieved favorable outcome and 43.8% had unfavorable outcome. Diffuse slowing on sleep EEG was associated with increased likelihood of unfavorable outcome. Epileptiform discharges were linked to a higher incidence of early post-stroke seizures. Conclusions Sleep EEG demonstrates greater sensitivity in detecting post-stroke cortical dysfunction compared with awake EEG. Diffuse slowing during sleep recording is associated with poorer 3-month functional outcome and may serve as a useful prognostic marker after ischemic stroke. Conflict of interest