A 5-Year Retrospective Examination of Cognitive Screening Test Stages in Normal Older Adults and Patients With Alzheimer’s Disease: The Tajiri Project

One conception of aging and cognitive deterioration is that cognitive decline becomes common with age, and de-mentia may be regarded as one extreme of the continuum. An alternative conception is that the cognitive process is spared by the aging process itself and that cognitive functioning of normal older adults and those with slight cognitive impairment, a CDR (Clinical Dementia Rating) score of 0.5 (suspected dementia), should be different. We examined changes in the screening test performances of 170 older adults over a 5-year period and found the following: (a) The CDR 0 (normal) participants did not show remarkable changes even in the older groups and (b) the subitems of orientation, memory, and so forth were useful for distinguishing normal older adults from early Alzheimer’s disease patients. The results support the idea that dementia is better conceptualized as an age-related than as an “aging-related ” disorder and that a CDR score of 0.5 should be considered very mild Alz-heimer’s disease. T is well known that subtle cognitive impairment can be present for several years before the clinical diagnosis of probable Alzheimer’s disease (AD; Bayles & Kaszniak, 1987). For assessing cognitive functions, the Mini-Mental State Exam (MMSE; Folstein, Folstein, & McHugh, 1975) has been widely used (Bassett & Folstein, 1991; Tombaugh & McIntyre, 1992). It provides a structured approach to men-tal status that screens for intellectual impairment and allows comparison of performance across time and among patient