Montreal Cognitive Assessment (MoCA): A validation study among prisoners

Abstract

Background

There are numerous scales for screening cognitive performance and thus identification of any potential deficits, but in spite of the vulnerability of the prison population to such problems, there has been no adequate validation of screening tools specifically for use with prisoners or others in the criminal justice system.

Aim

To validate the Montreal Cognitive Assessment (MoCA) for use with prisoners.

Methods

100 adult prisoners in one Portuguese prison were randomly invited by clinicians to take part in this study. A same size sample of community-living adult non-offenders of similar age was selected from the MoCA's normative study database in Portugal. For both groups, the key inclusion criterion was fluency in the Portuguese language. All participants completed the Mini Mental State Examination (MMSE) and the MoCA, both in Portuguese translation. Cronbach's alpha coefficient was calculated as an index of internal consistency and Pearson's r correlations calculated. Group performances were compared using independent samples t-test. Covariance analysis (ANCOVA) was computed with level of education as covariate. To measure the magnitude of the effect, ${\eta }_p^2$ was used. A receiver operating characteristics curve analysis was computed to evaluate the discriminatory accuracy of MoCA and MMSE.

Results

The MoCA showed a ‘reasonable’ internal consistency index (α = 0.75) as well as positive and significant correlations with the MMSE. As a cognitive measure, however, the MoCA showed consistently superior psychometric properties and higher discriminatory accuracy (MoCA = 89%) than the MMSE (65%). According to the Youden index, the optimal cut-off point for the MoCA is below 24 points, whereas for the MMSE, it is below 27.

Conclusions

The MoCA is a valid cognitive screening tool for use with prisoners. Further validations against detailed cognitive evaluation would be a useful next step.