title: Person-specific paths of cognitive decline in Alzheimer's disease and their relation to age.
abstract: Change in global and specific measures of cognitive function was studied in a cohort of 410 persons with Alzheimer's disease. Persons completed up to 5 annual evaluations; follow-up participation among survivors exceeded 90%. Average annual decline was 0.57 standard score units (95% confidence interval [CI]: -0.51 to -0.62) on a composite measure based on 17 individual tests and 3.26 points (95% CI: -3.06 to 3.46) on the Mini-Mental State Examination, but substantial heterogeneity was apparent. On both global and specific measures, rate of cognitive decline was reduced in older persons compared with younger persons. A similar effect was observed for estimated age of disease onset. The effect of age was approximately linear and was not attributable to education, sex, race, other conditions that impair cognition, or mortality. The results indicate that person-specific paths of cognitive decline in Alzheimer's disease vary substantially and suggest that in clinical settings some of this variability is related to age.
authors.affiliation: Rush Alzheimer's Disease Center, Rush-Presbyterian-St. Luke's Medical Center, Chicago, Illinois 60612, USA.
authors.forename: R S
authors.initials: RS
authors.lastname: Wilson
authors.forename: D W
authors.initials: DW
authors.lastname: Gilley
authors.forename: D A
authors.initials: DA
authors.lastname: Bennett
authors.forename: L A
authors.initials: LA
authors.lastname: Beckett
authors.forename: D A
authors.initials: DA
authors.lastname: Evans
mesh_terms: D000328:Adult; D000367:Age Factors; D017668:Age of Onset; D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000175:diagnosis* / Q000523:psychology; D003072:Cognition Disorders / Q000175:diagnosis* / Q000523:psychology; D016001:Confidence Intervals; D005163:Factor Analysis, Statistical; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D011569:Psychiatric Status Rating Scales / Q000706:statistics & numerical data; D011581:Psychological Tests / Q000706:statistics & numerical data*; D011594:Psychometrics