Dementia in intellectual disability: a review of diagnostic challenges

Abstract

The evaluation of dementia in individuals with intellectual disability (ID), which will guide subsequent intervention, care and management depends on the systematic review of a number of factors: (1) the individual historical context, obtained from multiple sources, (2) evaluation of the pre-existing cognitive, behavioural, psychiatric, medical and adaptive skill profile, (3) the constellation, and pattern of evolution, of presenting signs and symptoms, (4) results of focused investigations, and (5) refinement of the differential diagnosis. In patients with ID, standard clinical methods need to be supplemented by careful, longitudinal behavioural observations, and individually tailored assessment techniques. Co-morbidity, multiple biological, psychological and socioenvironmental factors, and complex interactions among events, are the reality for many ageing people with ID. Determining the various influences is often a formidable clinical task, but should be systematically carried out using medical, cognitive, behavioural, neuropsychiatric and psycho-social frameworks.