title: A prospective study of cognitive function and onset of dementia in cognitively healthy elders.
abstract: OBJECTIVE
  To examine the earliest cognitive changes associated with the onset of dementia as well as changes associated with normal aging.
  
  
  METHODS
  Longitudinal evaluation of participants with annual clinical and psychometric examinations for up to 15 1/2 years.
  
  
  METHODS
  Elderly volunteers (n = 82) enrolled with a Clinical Dementia Rating of 0 (cognitively intact) in longitudinal studies.
  
  
  METHODS
  None.
  
  
  METHODS
  Clinical Dementia Rating and results of a 1 1/2-hour psychometric battery.
  
  
  RESULTS
  As estimated with survival analysis, 40% of participants had a Clinical Dementia Rating greater than 0 (cognitive decline) within 12 years of enrollment; 59% of these were judged to have dementia of the Alzheimer type or incipient dementia. Participants with poorer performance on psychometric testing at enrollment were at higher risk for cognitive decline subsequently. The rate of change in psychometric performance before clinically detectable cognitive change occurred was not significantly different between those who eventually developed dementia and those who remained stable, except for performance on the Logical Memory subtest of the Wechsler Memory Scale. When subtle cognitive decline was clinically detected, however, an abrupt deterioration in performance on independently administered psychometric tests was observed.
  
  
  CONCLUSIONS
  Cognitively healthy elderly people maintain stable cognitive performance when measured longitudinally by both careful clinical evaluation and repeated psychometric testing. This stability is maintained unless and until they develop a dementing illness, at which time a sharp decline in performance is observed.
authors.affiliation: Department of Psychiatry, Alzheimer's Disease Research Center, Washington University, St Louis, Mo 63110, USA. rubing@psychiatry.wustl.edu
authors.forename: E H
authors.initials: EH
authors.lastname: Rubin
authors.forename: M
authors.initials: M
authors.lastname: Storandt
authors.forename: J P
authors.initials: JP
authors.lastname: Miller
authors.forename: D A
authors.initials: DA
authors.lastname: Kinscherf
authors.forename: E A
authors.initials: EA
authors.lastname: Grant
authors.forename: J C
authors.initials: JC
authors.lastname: Morris
authors.forename: L
authors.initials: L
authors.lastname: Berg
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology*; D003071:Cognition; D003704:Dementia / Q000503:physiopathology* / Q000628:therapy; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D011594:Psychometrics; D013997:Time Factors; D016896:Treatment Outcome