Post-stroke cognitive impairment is common even after successful clinical recovery

Abstract

Background and purpose: Cognitive impairment is common after stroke, but the prevalence and long-term significance of the diverse neuropsychological deficits on functional outcome are still not well known. The frequency and prognostic value of domain-specific cognitive impairments were investigated in a large cohort of ischaemic stroke patients.

Methods: Consecutive patients (n = 409), aged 55-85 years, from the acute stroke unit of the Helsinki University Hospital, Finland, were evaluated with extensive clinical and neuropsychological assessments 3 months post-stroke. Impairments within nine cognitive domains were determined according to age-appropriate normative data from a random healthy population. Functional disability was evaluated with the modified Rankin scale (mRS) 3 and 15 months post-stroke.

Results: In all, 83% patients showed impairment in at least one cognitive domain, whereas 50% patients were impaired in multiple (≥3) domains. In cases with excellent clinical recovery at 3 months (mRS = 0-1, no disability), the occurrence of any cognitive impairment was 71%. Memory, visuoconstructional and executive functions were most commonly impaired. A substantially smaller proportion of patients scored below the conventional or more stringent cut-offs in the Mini-Mental State Examination (MMSE). Domain-specific cognitive impairments were associated with functional dependence at 15 months regardless of stroke severity and other confounders.

Conclusions: Cognitive impairment as evaluated with a comprehensive neuropsychological assessment is prevalent in stroke survivors even with successful clinical recovery. Typically multiple domains and complex cognitive abilities are affected. MMSE is not sensitive in detecting these symptoms. Post-stroke cognitive impairment is strongly related to poor functional outcome.

Keywords: cognition; cognitive impairment; neuropsychology; stroke.