Dementia in adults with Down syndrome: diagnostic challenges.

Although dementia associated with Down syndrome is often presumed to be progressive and irreversible, variations in disease course have been described. In addition, prevalence rates have varied widely among studies. This interim report is a description of the status of 70 adults with Down syndrome who are being followed for signs of dementia. Of the 70, 12 met all criteria for dementia, 40 met subsets of criteria, and 18 met no criteria. Information is provided on instruments used, rationale for choice and revision of instruments as well as criteria used to identify dementia and changes in the status of the participants. The results suggest that extreme care is needed when diagnosing dementia in adults with Down syndrome, for both clinical and research purposes.