Screening for Alzheimer\'s Disease in Downs Syndrome

Abstract

Downs syndrome (DS), is associated with an increased incidence of Alzheimer’s disease (AD). Although pathological changes are ubiquitous by 60 years of age, prevalence rates are lower. The diagnosis of AD in persons with DS is challenging, complicated by atypical presentations, baseline intellectual disability and normal age associated cognitive decline. Effective screening is limited by a paucity of diagnostic criteria, cognitive screening instruments and screening programmes. Both observer-rated questionnaires and direct neuropsychological testing are suggested to screen for cognitive impairment, each with different strengths and weaknesses. This paper reviews commonly used screening instruments and explores the unique challenges of screening for AD in persons with DS. It concludes that single, one-dimensional screening tools and opportunistic evaluations are insufficient for detecting dementia in this population. These should be replaced by batteries of tests, incorporating informant questionnaires, direct neuropsychological testing, assessment of activities of daily living and behaviours, measured at baseline and reassessed at intervals. Developing these strategies into organized screening programmes should improve diagnostic efficiency and management.