Advancing knowledge into the clinical assessment of dementia.

Abstract

The aim of the present thesis was to identify and measure cognitive and social abilities in people with dementia and learning disabilities. In Chapter 1, normal agemg was discussed, distinguishing it from abnormal ageing and highlighting the problems it brings in terms of physical and psychological factors. Normal memory was also discussed and how the processes involved may be effected by dementia. Definitions of dementia were discussed in detail, outlining the neuropathology, neuropsychology and clinical signs of Alzheimer's disease, and the neuropsychology of multi-infarct dementia. The psychology of pseudodementia was presented and discussed and reference was made to the difficulties of a differential diagnosis. This was placed in the context of defining learning disabilities, such as Down's syndrome, and the complexity of assessing people who have both a learning disability and dementia. Social and cultural differences were discussed together with the influence of environmental factors in measuring dementia. Theoretical considerations about the difficulties in assessing people with learning disabilities, particularly people who have Down's syndrome and dementia, were presented and discussed. These issues arose from the abnormalities in intellectual development and therefore, impacted upon subsequent cognitive rehabilitation and integration into the community of such individuals. A description and critique of the instruments used in the clinical studies ensued with important reference to the reliability, validity, and standard error and norms of each tool used. Finally, the goals of the study series were presented and discussed. Part I: Empirical Studies (Published Papers) Clinical studies were presented in chapters 2 - 5. All clients participating in the studies were randomly selected from consultant psychiatrists' lists ofpeople living in their own homes or in voluntary sector group homes in England. In Chapter 2, a neuropsychological test battery was devised in order to identify dementia in people with Down's syndrome. This battery comprised a series of standardised neuropsychological tests and rating scales measuring intellectual profiling, cognitive and social functioning and ability, and anxiety and depression. In addition to gathering biographical information, self-care information was also gathered. The Dementia Questionnaire for Mentally Retarded Persons proved to be a useful tool for indicating general areas of clients' skills that had declined; however, there is still a need for a definitive assessment of depression for these clients in order to discriminate between the effects of depression and those ofdementia. In Chapter 3, clients with Down's syndrome and non-Down's syndrome learning disabilities were assessed usmg specially selected neuropsychological assessment tools at two points separated by twelve months. Evidence was found to support hypothesis 1 which suggested that people with Down's syndrome show a greater decline in social abilities with age, compared with other groups ofpeople with learning disabilities. Statistically, score changes reflecting the social abilities of the Down's syndrome clients were found to be significantly greater (p < .002) than those of the non-Down's syndrome clients. Findings were explained in terms of poor language abilities in the Down's syndrome people generally, and the link between declining social abilities and dementia. In Chapter 4, forty-one clients with learning disabilities were assessed using specially selected neuropsychological assessment tools at two time points separated by twelve months. Evidence for hypothesis 1 suggested that people with Down's syndrome show a greater decline in cognitive abilities with age, compared with other groups of people with learning disabilites. A weak linear association (p < .004; r = .625; 2-tailed) between cognitive performance and social abilities was also found for the Down's syndrome clients, supporting hypothesis 2. Findings were explained in terms of the link between declining cognitive abilities and dementia. In Chapter 5, a clinical investigation was undertaken to determine the rate of decline in cognitive and social abilities in 16 clients with learning disabilities, 8 of which had Down's syndrome. Clients assessed at 6 months using specially selected neuropsychological tests and rating scales measuring cognitive and social abilities as well as intellectual profiling. Both Down's syndrome and non-Down's syndrome clients were found to decline in cognitive abilities (Down's syndrome: p <.005; I-tailed); NonDown's syndrome: p <.01; I-tailed; p <.005; I-tailed). The Down's syndrome clients also showed decline in social abilities (p <.005; I-tailed) over 6 months suggesting that changes between the two client groups may be significantly greater over a longer period, ie 12 months. Hence, the rate of change in cognitive abilities for the Down's syndrome clients was faster. Part 11: Evaluation of Treatment and Services (Published Papers) In Chapter 6, a new version of the Benton Visual Retention Test for assessing people's memory functioning was evaluated. Findings showed that the conventional method of testing was preferred and not significantly different in terms of efficacy and reliability of measurement. In Chapter 7, the potential benefits of Aricept, an acetylcholine esterase inhibitor, was investigated. There were significant effects and benefits for patients who had mild-to-moderate Alzheimer's disease over a short period of time. However, the results were encouraging as they signalled the first documentation of the effect and a promising future for a possible remission of the disease. In Chapter 8, a support group for wives of husbands with dementia was presented and discussed. The psychoeducation support group was shown to be an effective way of supporting newly diagnosed people with dementia and their carers. In Chapter 9, a new interdisciplinary clinic for people with cognitive abilities was discussed. Importance in the constitution of the clinic personnel as well as the fbcus on assessment and follow-up treatment was emphasised. Part Ill: Future Direction (Published Papers) In Chapter 10, the importance of assessing people with dementia in the early stages of diagnosis and at particular intervals was demonstrated in the context of the legal process. Suggestions were made for improving the test for testamentary capacity. Part IV: In Summary Discussion in Chapter 11 covers the empirical work presented together with suggestions for future research, namely considering the differences between discrete types of dementias such as multi-infarct (vascular) dementia versus Alzheimer's disease and also longitudinal studies. Interesting findings from the clinical studies revealed a greater decline in social abilities of Down's syndrome clients versus non-Down's syndrome clients. These findings were explained in terms of poor language abilities in Down's syndrome clients generally, and the link between declining social abilities and dementia. A link between cognitive performance and social abilities was also found for the Down's syndrome clients. Findings of declining cognitive abilities in both groups of clients were associated with dementia; and in particular, with a failure of the Central Executive System and Articulatory Loop System, considered to be important in nonnal memory. Modifying assessment techniques such as by computerisation is presented and treatment efficacy using the acetycholinesterase inhibitor, Aricept, is presented and discussed. The establishment of cognitive assessment clinics is also presented as a way of providing a comprehensive service for people with early onset dementia. Service implications for people with learning disabilities is discussed and finally, ways of improving the test for testamentary capacity for people with dementia is detailed. Collectively, these writings significantly contribute to our academic and clinical knowledge of assessing dementia. We have learned a great deal from studying and helping people with Down's syndrome; however, perhaps more importantly, this work should contribute significantly to our rather limited knowledge of assessing dementia in people with Down's syndrome and thus may step towards improving and widening access to service provision for these valued people.