Montreal Cognitive Assessment: Exploring the impact of demographic variables, internal consistency reliability and discriminant validity in a South African sample

Abstract

The Montreal Cognitive Assessment (MoCA) is widely used to screen for cognitive impairment and has shown a good capacity to identify cognitive impairment. However, its psychometric properties have not been sufficiently studied in the South African context. Therefore, this study aimed to investigate (1) the influence of demographic variables (age, years of education, and gender) on total MoCA scores; (2) the internal consistency reliability of the test and (3) the discriminant validity of the total MoCA score. This study analysed secondary quantitative data, utilising a cross-sectional, between-subjects design. All participants completed the English MoCA version 8.1. The control sample (n = 89) included healthy South African adults who speak English as a second or third language and who have been educated in public schools. The clinical sample (n = 83) included patients with human immunodeficiency virus (HIV) and a comorbid disorder, either psychiatric (n = 70) or neurocognitive (n = 13). Total MoCA scores were significantly correlated with years of education (p < 0.001) and age (p = 0.007) but not gender. Cronbach’s alpha was 0.64 revealing moderate internal consistency. The total MoCA score was not a significant predictor of diagnostic status, indicating poor discriminant validity of the MoCA in this sample. The MoCA appears not to be a useful screening or diagnostic tool in samples with similar characteristics.