title: Importance of subtle amnestic and nonamnestic deficits in mild cognitive impairment: prognosis and conversion to dementia.
abstract: OBJECTIVE
  To evaluate baseline characteristics and conversion to dementia in mild cognitive impairment (MCI) subtypes.
  
  
  METHODS
  We prospectively evaluated conversion to dementia in 106 patients with amnestic MCI (A-MCI) as defined by Petersen's operationalized criteria on a paragraph recall task, amnestic-subthreshold MCI (AS-MCI) as defined by impairment on the ADAS-cog delayed word list recall with normal paragraph recall, nonamnestic MCI (NA-MCI) defined by a nonmemory domain, and in 27 patients with subjective memory loss who had no deficit on formal neuropsychological testing.
  
  
  RESULTS
  For all MCI subtypes, the 4-year conversion to dementia was 56% (14% annually) and to AD was 46% (11% annually). Conversion to AD in the A-MCI (56%) was similar to the rate in AS-MCI (50%). Conversion to AD in the A-MCI and AS-MCI combined was 56% (14% annually). Conversion to dementia in the NA-MCI was 52% (13% annually) and the majority converted to AD (62%).
  
  
  CONCLUSIONS
  All MCI subtypes are at risk of converting to AD if the groups are carefully defined by an abnormal psychometric domain. All subtypes except subjective memory loss converted to AD at higher than expected rates. Both the A-MCI and AS-MCI subtypes had a similarly high rate of conversion to AD. The deficit on a word list recall task may develop before an abnormality on delayed paragraph recall is evident, at least in some subjects.
authors.affiliation: Department of Neurology, Baylor College of Medicine, Houston, TX 77030, USA. rountree@bcm.edu
authors.forename: S D
authors.initials: SD
authors.lastname: Rountree
authors.forename: S C
authors.initials: SC
authors.lastname: Waring
authors.forename: W C
authors.initials: WC
authors.lastname: Chan
authors.forename: P J
authors.initials: PJ
authors.lastname: Lupo
authors.forename: E J
authors.initials: EJ
authors.lastname: Darby
authors.forename: R S
authors.initials: RS
authors.lastname: Doody
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000647:Amnesia / Q000175:diagnosis* / Q000453:epidemiology*; D003072:Cognition Disorders / Q000175:diagnosis* / Q000453:epidemiology*; D003704:Dementia / Q000175:diagnosis* / Q000453:epidemiology*; D003937:Diagnosis, Differential; D018450:Disease Progression; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D011446:Prospective Studies; D011594:Psychometrics; D012720:Severity of Illness Index