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Keywords:

  • cerebrovascular disease;
  • cognitive impairment;
  • neuropsychology;
  • stroke

Objective

To determine the validity of the Montreal Cognitive Assessment (MoCA) and the Mini–Mental State Examination (MMSE) as screening tools for cognitive impairment after stroke.

Materials and methods

Cognitive assessments were administered over 2 sessions (1 week apart) at 3 months post-stroke. Scores on the MoCA and MMSE were evaluated against a diagnosis of cognitive impairment derived from a comprehensive neuropsychological battery (the criterion standard).

Results

Sixty patients participated in the study [mean age 72.1 years (SD = 13.9), mean education 10.5 years (SD = 3.9), median acute NIHSS score 5 (IQR 3–7)]. The MoCA yielded lower scores (median = 21, IQR = 17–24; mean = 20.0, SD = 5.4) than the MMSE (median = 26, IQR = 22–27; mean = 24.2, SD = 4.5). MMSE data were more skewed towards ceiling than MoCA data (skewness = −1.09 vs −0.73). Area under the receiver operator curve was higher for MoCA than for MMSE (0.87 vs 0.84), although this difference was not significant (χ2 = 0.48, P = 0.49). At their optimal cut-offs, the MoCA had better sensitivity than the MMSE (0.92 vs 0.82) but poorer specificity (0.67 vs 0.76).

Conclusions

The MoCA is a valid screening tool for post-stroke cognitive impairment; it is more sensitive but less specific than the MMSE. Contrary to the prevailing view, the MMSE also exhibited acceptable validity in this setting.