Underestimation of cognitive impairments by the Montreal Cognitive Assessment (MoCA) in an acute stroke unit population

• The MoCA is increasingly used for detecting post-stroke cognitive impairment.
• We examined the prevalence of cognitive impairment in MoCA-intact stroke patients.
• 78% of patients were impaired on neuropsychological assessment.
• Flawless performance in a MoCA domain did not necessarily reflect intact cognition.
• Neuropsychological assessment is vital for reliable detection of stroke impairment.

Background and purposeThe Montreal Cognitive Assessment (MoCA) is an increasingly popular clinical screening tool for detecting cognitive impairment in stroke, but few studies have directly compared performance on the MoCA with neuropsychological assessment. Our retrospective study examined the extent to which intact performance on the MoCA reflects intact cognition as determined by neuropsychological assessment.MethodsIn this retrospective study, cognitive profiles for 136 acute stroke patients admitted to the Acute Stroke Unit who had available MoCA and neuropsychological assessment data were examined.Results22% of our patients were deemed cognitively intact on the MoCA. Of these, 78% were found to be impaired (≤ 5%ile) on neuropsychological assessment in one or more cognitive domains. The most common impairments were in general intelligence, information processing speed and visual memory; three areas not assessed by the MoCA. In addition, a high proportion (up to 59%) of patients who scored the maximum points in one of the MoCA-specified domains were impaired on comparable neuropsychological assessment.ConclusionsOur findings suggest that although the MoCA may be a useful screening tool post-stroke in detecting gross impairments, neuropsychological assessment is still necessary for a comprehensive and reliable detection of domain-specific cognitive deficits, which can more reliably inform us for realistic goal setting and vocational advice vital for effective rehabilitation.