Validity and applications of the Montreal cognitive assessment for the assessment of vascular cognitive impairment.

Cognitive impairment is common among patients with stroke or other cerebrovascular disease and influences long-term outcome, including occupational functioning. Recognition and monitoring of mild cognitive impairment is thus essential to good patient care. The Montreal Cognitive Assessment (MoCA) has been suggested as a brief screening test of vascular cognitive impairment. This paper presents a critical review of the research literature evaluating the validity and utility of this test with the aim of informing future clinical and research practice. A total of 30 papers employing the MoCA in the context of cerebrovascular disease were identified. Reporting of the methods and results of such studies tended to fall short of the established reporting guidelines. Under-specification of the exclusion criteria applied and their impact make it difficult to assess the potential impact of sampling bias and loss to follow-up. Nevertheless, content validity evidence suggests that the MoCA covers most of the domains that represent cognitive impairment in cerebrovascular disease, with mixed evidence for its preferential sensitivity to the type of cognitive impairment encountered in the context of vascular disease. Evidence clearly supports the need to establish norms and cut-offs for the MoCA that are culturally appropriate and that are matched to the range of cognitive impairment that is present in the population being assessed. Recent modifications of the MoCA have been developed for assessing patients with visual impairment or restricted mobility, which may reduce the impact of 'untestability' on cognitive screening in the clinic or research context. The MoCA correlates well with other measures of cognitive and functional abilities in patients with cerebrovascular disease, and may also predict future response to rehabilitation and long-term occupational outcome. Further research is needed to provide evidence for the validity of the MoCA in longitudinal studies. However, it compares favourably to the Mini Mental State Examination as a screening test that is sensitive to the milder forms of cognitive impairment that often accompany cerebrovascular disease.