POPULATION-BASED STUDY OF THE PREVALENCE AND PRESENTATION OF DEMENTIAIN ADULTS WITH DOWNS-SYNDROME

Background The reported prevalence rates of dementia in people with Do wn's syndrome have varied considerably across studies. The aim of this study was to investigate the extent of clinical change with age using an established diagnostic instrument in an unbiased, population-based sample or older people with Down's syndrome. Method Changes in memory , personality, general mental functioning and daily living skills were assessed using a modified version of the informant interview or the C ambridge Examination for Mental Disorders of the Elderly (CAMDEX). Res ults Age-specific prevalence rates of dementia varied according to the diagnostic criteria used. Using CAMDEX criteria for Alzheimer's disea se, prevalence rates increased from 3.4 to 10.3 to 40% in the 30-39, 4 0-49 and 50-59 age group, respectively. Conclusions Overall. the age-r elated pattern of presentation and dementia diagnoses differs from tha t seen in the general elderly population, However, age-specific preval ence rates of Alzheimer's disease were similar but 30-40 years earlier in life.