TitleThe effects of preclinical dementia on estimates of normal cognitive functioning in aging.
Publication TypeJournal Article
Year of Publication1996
AuthorsSliwinski, MJ, Lipton, RB, Buschke, H, Stewart, W
JournalJ Gerontol B Psychol Sci Soc Sci
Volume51
Issue4
PaginationP217-25
Date Published1996 Jul
ISSN1079-5014
KeywordsAge Factors, Aged, Aging, Cognition Disorders, Dementia, Educational Status, Female, Humans, Longitudinal Studies, Male, Psychiatric Status Rating Scales
Abstract

<p>Individuals with preclinical dementia have begun to decline cognitively, but still perform within normal limits on cognitive testing. As a group, subjects with preclinical dementia have lower scores on neuropsychological tests than their dementia-free counterparts. This study examines the effects of preclinical dementia on estimates of normal cognitive function in the aged using data from a longitudinal study. Individuals with preclinical dementia at baseline were retrospectively identified based on subsequent development of dementia. Age-adjusted norms were computed using baseline data for the Selective Reminding Test and the WAIS verbal and performance scores, both including (conventional norms) and then excluding (robust norms) preclinical cases. The results indicate that by failing to exclude preclinical dementia, conventional normative studies underestimate the mean, overestimate the variance, and overestimate the effect of age on cognitive measures. Methods are discussed for selecting robust elderly samples that are relatively free of contamination by preclinical dementia.</p>

DOI10.1093/geronb/51b.4.p217
Alternate JournalJ Gerontol B Psychol Sci Soc Sci
PubMed ID8673642
Grant ListAG-03949 / AG / NIA NIH HHS / United States
AG-12448 / AG / NIA NIH HHS / United States
HD-01799 / HD / NICHD NIH HHS / United States