Comment: The quality of evidence is downgraded by inconsistency (heterogeneity in patients) indirectness (differences is patients, a threshold of MoCA used in studies is probably not correct) and imprecise results (most of the studies were small).
A Cochrane review «Montreal Cognitive Assessment for the detection of dementia»1 «Davis DH, Creavin ST, Yip JL et al. Montreal Cognitive Assessment for the detection of dementia. Cochrane Database Syst Rev 2021;7:CD010775. »1 included 7 studies with a total of 9422 subjects. Three studies were conducted in memory clinics, two in hospital clinics, none in primary care and two in population-derived samples. The original instructions for use of the MoCA recommended a threshold of 25/26 in order to identify any cognitive impairment but this is not necessarily the optimum threshold for diagnosing dementia, which may be several points lower. Most of studies recruited only small samples, with only one having more than 350 participants. The prevalence of dementia was 22% to 54% in the clinic-based studies, and 5% to 10% in population samples. In the four studies that used the recommended threshold score of 26 or over indicating normal cognition, the MoCA had high sensitivity of 0.94 or more but low specificity of 0.60 or less.
Further studies that do not recruit participants based on diagnoses already present (case-control design) but apply diagnostic tests and reference standards prospectively are required. Thresholds lower than 26 are likely to be more useful for optimal diagnostic accuracy of MoCA in dementia, but this requires confirmation in further studies.