Dementia in adults with mental retardation: assessment at a single point in time.

Dementia status of 273 adults with mental retardation was rated based upon two extensive evaluations conducted 18 months apart. Overall, 184 individuals did not have dementia, 33 had possible or definite dementia, and 66 had findings suggesting uncertain or questionable status. These ratings were compared to binary classifications (dementia vs. no dementia) generated from the Dementia Questionnaire for Persons With Mental Retardation (Evenhuis, 1995) and the IBR Mental Status Examination (Wisniewski & Hill, 1985). When performance was referenced to IQs (established earlier in adulthood), quantitative criteria effectively distinguished between individuals with and without dementia based upon assessment at a single point in time. Findings suggest that procedures of this type could soon contribute to more accurate and rapid diagnoses of dementia.