Ganguli M, Ratcliff G, DeKosky ST. Cognitive test scores in community-based rural elderly with and without dementia. Aging and Mental Health, 1 (2): 176-180, 1997.

ABSTRACT:

In an epidemiological survey of a rural, largely blue-collar, community, 1,363 randomly selected adults, aged 65+ yrs, were administered a cognitive screening battery, including in part the Consortium to Establish a Registry for Alzheimer's Disease (CERAD) tests, the Mini-Mental State Examination; and Word List Learning, Recall, and Recognition. Cognitively impaired Ss and cognitively intact controls underwent independent standardized diagnostic assessments and were rated on the Clinical Dementia Rating (CDR) scale. Overall, Ss at higher CDR levels (more severe dementia) had worse scores on all tests, showing that standard neuropsychological tests are valid for characterizing the cognitive impairments seen in dementia, even in community settings. However, nondemented scores on the CERAD tests in this community-based sample were lower than reported from CERAD's pooled healthy controls from Alzheimer's Disease Centers nationwide. Thus, "normal" scores from specialty dementia clinics, where there may be a selection bias, may differ from normative scores from rural and/or less-educated populations. Patients from such populations may be functionally intact despite low test scores.