Cognitive impairment in moderate to severe stroke: Is the MoCA an appropriate tool for South African stroke survivors?

Abstract

Background The Montreal Cognitive Assessment (MoCA) is widely used to screen for Post Stroke Cognitive Impairment. However, its clinical utility for the stroke survivor population and populations outside of Western, English-speaking cultures has been extensively critiqued. Cognitive impairments in stroke are common, affecting between 20 to 80% of stroke survivors. Attention, information processing, memory, and executive functioning are cognitive skills frequently affected in Post Stroke Cognitive Impairment. These impairments occur at varying severity levels and can significantly affect performance in multiple areas of daily functioning. An appropriate cognitive screening tool needs to accurately identify areas of dysfunction in Post Stroke Cognitive Impairment (PSCI) allow these impairments to be adequately managed through the therapy process. 2.1.1. Aims The aim of this study was to determine whether the MoCA is a valid screening tool for post-stroke cognitive impairment in moderate-to-severely impaired stroke survivors in South Africa. 2.1.2. Methods A quantitative, cross-sectional design was employed. A small, expert consensus group was used to gain information around cognitive skills from the Comprehensive ICF Core Set for Stroke which could be assessed using the MoCA. Nominal Group Technique processes were utilised to conduct the group and gather data. Responses from the consensus group were analysed from the transcription and recording, to confirm the cognitive skills from the ICF Core Set for Stroke agreed upon by all experts for each section of the MoCA. Thereafter, a self-administered, online survey was used to collect data on perceptions of occupational therapists who work with stroke survivors in South Africa on the utility of the MoCA for assessing Post-Stroke Cognitive Impairment in moderate to severely impaired stroke survivors in South Africa. 21 iv completed responses were analysed using the Content Validity Index Method and descriptive statistics. 2.1.3. Conclusion This study was completed following ethical approval by the Wits Human Research Ethics Committee. A total of 21 responses were collected (n=21) with 17 and 4 participants from the private and public sectors respectively. This study found the MoCA to be largely a valid tool for screening cognition in stroke survivors living in South Africa. However, this was not without critique. Low simplicity scores and poor item-level validity of the executive function were areas of concern for participants considering diverse demographics of stroke survivors in South Africa, as well as the confounding effects of other stroke-related impairments. Moreover, participants felt that the MoCA does not adequately screen for PSCI, nor does it screen the most commonly affected cognitive skills following stroke. Despite these concerns, the MoCA remains widely used. This is due to a lack of other screening tools which are recommended for use with stroke survivors and have some adaptation to account for demographics (specifically language). Future research should focus on adding to the body of information around the MoCA and its clinical utility for stroke survivors in South Africa to develop a set of normative data, build a foundation of empirical data on the validity of the MoCA in both the private and public sectors, and develop a body of information which could help with the development of a diagnostic and contextually relevant cognitive screening tool. Clinicians using the MoCA with stroke survivors in South Africa should be critical of the interpretation of scores considering demographic and other stroke-related factors. Furthermore, other resources and tools such as the Comprehensive ICF Core Set for Stroke, the Cognitive Assessment for Stroke Patients, the Oxford Cognitive Screen and the MMSE should be utilised to supplement the MoCA administration to triangulate data on test performance; and provide a guide/checklist for commonly affected cognitive skills to be adequately assessed and observed during the evaluation phase of rehabilitation