Memory and normal ageing in adults with intellectual disabilities: a research portfolio

Abstract

BACKGROUND: Assessment of dementia in adults with intellectual disabilities poses specific challenges. Firstly, there is a paucity of validated, standardised and appropriate neuropsychological assessments of memory for adults with intellectual disabilities. Secondly, there are difficulties determining whether performance on neuropsychological assessments are attributable to preexisting intellectual disabilities, ‘normal’ ageing or part of a dementing process. A systematic review was therefore carried out to examine if there are memory changes associated with ‘normal’ ageing in the Down syndrome population. Following this an exploratory empirical research project was undertaken to examine one aspect of construct validity (i.e. convergent validity) of an associative memory test in a sample of adults with intellectual disabilities. This research project is presented as a journal article titled ‘Convergent validity of the Visual Association Test (VAT) in adults with intellectual disabilities’.

METHODS: 40 participants aged between 18-45 years were recruited from Community Learning Disability Teams. Participants completed the VAT and subtests of the modified Cambridge Cognitive Examination (CAMCOG-DS). IQ was assessed using the Wechsler Adult Intelligence Scale, Fourth Edition (WAIS-IV). Correlational analysis of the test variables were carried out. Participants with a diagnosis of dementia were excluded from the study.

RESULTS: All participants performed well on the VAT irrespective of age, gender or IQ. It was well received by participants. No significant correlations were found between the VAT and the subtests of the CAMCOG-DS or with the subtests of the WAIS-IV. Therefore, there was no evidence of convergent validity with this test in this sample of participants.

CONCLUSIONS: While the VAT was found to be an easy, quick test to use with people with intellectual disabilities and all participants scored above ‘floor’ level, it was not found to have convergent validity with the CAMCOG-DS. Further research is needed to determine if the VAT represents a useful tool for assessment with this population.