Excessive daytime sleepiness may predict early post-stroke cognitive impairment in elderly with non-disabling ischemic stroke.

Background: Daytime sleepiness is common in the acute phase of cerebral ischemic stroke and affects the clinical outcome, but whether it is associated with post-stroke cognitive function remains unclear.

Objective: To define the relationship between daytime sleepiness and early cognitive impairment after non-disabling ischemic stroke in elderly.

Methods: This prospective study included consecutive elderly patients with acute non-disabling ischemic stroke (aged > 60 years; NIHSS score ≤ 3 at admission; onset-to-enrollment time ≤ 7 days). Excessive daytime sleepiness (EDS) was diagnosed based on the Epworth Sleepiness Scale (ESS). Cognition was assessed by the Montreal cognitive assessment (MoCA) at admission and at 3-, 12-month follow-ups. Cognitive impairment was defined as MoCA score < 26 (≥12 years education) or < 25 (<12 years education). According to MoCA score at 3-month, patients were divided into two groups: Early post-stroke cognitive impairment (PSCI) group, and Non-PSCI group. Intergroup comparisons were performed for general demographic data, laboratory information, imaging data, ESS scores, and MoCA scores, followed with further correlation analysis between ESS scores and early PSCI.

Results: Of the 243 enrolled patients (mean age, 68.7 ± 6.6 years; female, 35.4 %), 160 (65.8 %) developed early PSCI. The two groups of patients were significantly different in ESS score during the acute phase, history of hypertension, coronary heart disease, atrial fibrillation, C-reactive protein, TOAST type, Fazekas scale of leukoaraiosis, MTA score of hippocampal volume. After adjustment for potential confounding variables, ESS score during the acute phase was positively associated with early PSCI (adjusted odds ratio 1.146, 95 % confidence interval 1.040-1.262, P = 0.006). According to receiver operating characteristic analysis, the best projecting factor for early PSCI was an ESS score ≥ 7 (area under the curve 0.593; sensitivity 48.1 %; specificity 69.9 %). Besides early PSCI, EDS during the acute phase was also associated with a higher risk of stroke recurrence and poor outcomes.

Conclusions: The occurrence of early PSCI in elderly patients with non-disabling ischemic stroke was related to EDS during the acute phase. Attention to ESS score during the acute phase is needed in these elderly patients for early diagnosis and timely intervention of PSCI.