Background: The Montreal Cognitive Assessment (MoCA) is an increasingly popular screening tool for detecting cognitive impairment post-stroke. However its' test accuracy by stroke lateralisation is as yet unknown. Aim: Our aim was to investigate whether the test accuracy of the MoCA differs by stroke lateralisation across different cognitive domains. Methods: We retrospectively examined the cognitive profiles of 228 subacute stroke patients (86 Left, 142 Right), comparing MoCA-total and domain-specific scores with performance on detailed neuropsychological assessment. Results: The prevalence of cognitive impairment detected on neuropsychological assessment was high and relatively comparable between the right and left hemisphere stroke groups (91% and 93% respectively). Notably however, 29% of the right stroke group and 6% of the left stroke group achieved a "cognitively-intact" MoCA score (≥25). A high proportion of right stroke patients who had an overall MoCA-intact score were found to be impaired in intellectual functioning, processing speed, executive functions and non-verbal memory on neuropsychological assessment. Furthermore, a high proportion of patients who scored fullmarks within a MoCA-specified domain, irrespective of their overall score, were found to have impairment on corresponding neuropsychological assessment for both stroke groups. Conclusions: Particular care needs to be taken in interpreting MoCA-intact performance for right hemisphere patients due to its poor sensitivity to right hemisphere deficits. Scoring maximum points within a MoCA-specified domain also does not necessarily indicate intact cognitive functioning in that domain. Clinicians should consider supplementing their MoCA assessment with additional tools to increase the test accuracy of detecting relevant cognitive impairments post-stroke.

Background: The Montreal Cognitive Assessment (MoCA) is a popular cognitive screening tool used in stroke, but lacks sensitivity for detecting impairment in stroke-relevant domains of processing speed, non-verbal memory and executive functions. Our aim was to assess whether the test accuracy of the MoCA can be improved with additional tailored screening items targeting these three domains. Methods: We included 196 patients admitted to an acute stroke unit at the National Hospital for Neurology and Neurosurgery, Queen Square (QS), London. Participants completed the MoCA as well as a series of additional QS-screening items designed to assess speed of processing, non-verbal memory and executive functions. Performance on the MoCA and QS screening items was compared with performance on "gold standard" neuropsychological assessment. Results: In our sample, 22% of patients were classified as "cognitively intact" on the traditional MoCA alone (>25). However, when tested on the QS-screening items, 40% of these patients failed on speed of processing, 56% failed on non-verbal memory and 26% failed on executive functions. Compared with neuropsychological assessment, the QSscreening items had good sensitivity (QS-Speed: 0.85; QS-Vis: 0.71; QS-EF: 0.73) and modest specificity (QS-Speed: 0.59; QS-Vis: 0.39; QS-EF: 0.54), regardless of stroke lateralisation. Conclusion: Additional screening items detected impairments in speed of processing, nonverbal memory and executive functions over and above those captured using the standard MoCA. The use of these QS-screening items improves the detection of post-stroke cognitive deficits in domains not adequately covered by the standard MoCA.

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