Contralateral interictal epileptiform discharges in acute stroke: When the unaffected hemisphere matters

Objective: This study aimed to assess the prevalence and predictive factors of contralateral-interictal epileptiform discharges (c-IEDs) in patients with acute stroke (AS) using point-of-care EEG within the first 72 h of admission. Methods: We retrospectively analyzed the data of AS patients who underwent point-of-care EEG within 72 h of admission between September 2020 and May 2023 of a single-center Stroke Unit. A multivariate logistic regression model identified variables associated with the onset of c-IEDs. Results: Among 647 patients, 148 (22.9%) exhibited IEDs on EEG within 72 h of admission. Of these, 21 patients (14.2%) showed exclusively contralateral IEDs, while 127 patients (85.8%) exhibited ipsilateral IEDs, including 28 (18.9%) with contralateral spread. Independent predictors of c-IEDs occurrence included NIHSS at admission (p = 0.012), stroke lesion volume (p = 0.048) and C-reactive protein levels (p = 0.009). Conclusion: This study highlights the pivotal role of early point-of-care EEG in detecting c-IEDs in patients with AS, observed in 3.25% of the cohort. Higher NIHSS scores at admission, larger stroke lesion volumes, and elevated CRP levels were identified as independent predictors of c-IEDs. Significance: These findings suggest that the identification of c-IEDs may serve as an additional marker of stroke severity.