Assessment of Cognition in People with Intellectual Disabilities Using a Novel Set of Neuropsychological Tests

Background: Improving the diagnosis of dementia in people with an intellectual disability is vital for early intervention and effective treatment and improving the quality of life for individuals, their families, or carers. Dementia is a risk factor for people with an intellectual disability, and neuropsychological assessment is a valuable diagnosis component. However, there has been difficulty in establishing tests for use with this population. A literature review was undertaken to gather research on neuropsychological tests for assessing cognitive impairment in adults with an intellectual disability. This was followed by an empirical study to pilot a novel test set for assessing dementia in people with an intellectual disability and derive preliminary data. Methods: This exploratory acceptability and feasibility study adopted a cross-sectional design to develop an understanding of the usefulness and appropriateness of the novel measure by piloting it with a sample of seven participants with an intellectual disability. Quantitative data is reported using the test scores, and qualitative data is reported using verbal feedback on the participants’ experience completing the measure. Results: A total of 36 studies were included in the literature review, reporting on 81 directly administered single-domain instruments used in testing of cognitive deterioration in people with an intellectual disability. The majority of the samples included people with Down syndrome. The results were variable, with some instruments developed specifically for this population. The novel test set proved acceptable and feasible for people with an intellectual disability but requires some modifications. Particular challenges were found for the tests of executive function, confirming the literature review findings. Conclusions: The results will inform modification of the measure for future piloting with larger and different samples of people with an intellectual disability.