title: Preclinical Alzheimer disease: neuropsychological test performance 1.5 to 8 years prior to onset.
abstract: OBJECTIVE
  To determine if individuals ultimately diagnosed with Alzheimer disease (AD) exhibited evidence of cognitive impairment on neuropsychological tests administered between 1.5 years and 8.1 years before dementia onset.
  
  
  METHODS
  A total of 693 community-dwelling individuals, part of the Cardiovascular Health Study, completed a neuropsychological test battery in 1991/92. Subjects were followed annually over the next 8 years (median follow-up = 7.4 years). Seventy-two individuals were ultimately diagnosed with AD (median follow-up = 4.5 years): 24 with AD onset 1.5 to 3.4 years after baseline neuropsychological testing, 20 with AD onset 3.5 to 5.0 years after testing, and 28 with onset 5.1 to 8.1 years after testing. A total of 621 individuals remained nondemented throughout the 8 years of follow-up (median follow-up = 7.5 years).
  
  
  RESULTS
  Subjects ultimately diagnosed with AD had poorer scores on baseline neuropsychological measures than subjects who remained nondemented. Although individuals closest to AD onset (i.e., 1.5 to 3.4 years) performed the most poorly, cognitive impairment was detected in individuals who did not develop AD until 5 to 8 years later.
  
  
  CONCLUSIONS
  Cognitive changes can be detected well before onset of Alzheimer disease.
authors.affiliation: University of Pittsburgh, Oxford Building, Room 738, Pittsburgh, PA 15213, USA. saxtonja@msx.upmc.edu
authors.forename: J
authors.initials: J
authors.lastname: Saxton
authors.forename: O L
authors.initials: OL
authors.lastname: Lopez
authors.forename: G
authors.initials: G
authors.lastname: Ratcliff
authors.forename: C
authors.initials: C
authors.lastname: Dulberg
authors.forename: L P
authors.initials: LP
authors.lastname: Fried
authors.forename: M C
authors.initials: MC
authors.lastname: Carlson
authors.forename: A B
authors.initials: AB
authors.lastname: Newman
authors.forename: L
authors.initials: L
authors.lastname: Kuller
mesh_terms: D017668:Age of Onset; D000544:Alzheimer Disease / Q000175:diagnosis* / Q000453:epidemiology / Q000523:psychology; D002318:Cardiovascular Diseases / Q000453:epidemiology; D003072:Cognition Disorders / Q000175:diagnosis* / Q000523:psychology; D015331:Cohort Studies; D015986:Confounding Factors, Epidemiologic; D018450:Disease Progression; D042241:Early Diagnosis; D004522:Educational Status; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008569:Memory Disorders / Q000175:diagnosis / Q000523:psychology; D009483:Neuropsychological Tests; D011237:Predictive Value of Tests; D016016:Proportional Hazards Models; D012306:Risk; D012680:Sensitivity and Specificity; D013997:Time Factors