title: Amnestic mild cognitive impairment and early Alzheimer's disease in an asian memory clinic - evidence for a clinical spectrum.
abstract: OBJECTIVE
  To determine if mild cognitive impairment (MCI) represents a continuum of cognitive and functional deficits.
  
  
  METHODS
  Clinical data of 164 subjects with no dementia (ND, n = 52), uncertain dementia (n = 69), and mild probable Alzheimer's disease (AD, n = 43) were reviewed. Uncertain dementia patients were classified as pre-MCI (n = 11), early amnestic MCI (e-aMCI, n = 15) and late amnestic MCI (l-aMCI, n = 15). Cognitive assessments [Chinese Mini-Mental State Examination (CMMSE) and a validated neuropsychological battery], functional assessments (Lawton's scale for instrumental activities of daily living) and neuroimaging (ischemic lesions and medial temporal lobe atrophy) were reviewed.
  
  
  RESULTS
  ND, aMCI and mild AD subjects demonstrated a significant trend for worsening performance for all cognitive and functional measures (ANOVA, p < 0.05). Pre-MCI subjects performed significantly better than aMCI subjects in all verbal memory domains (p < 0.001), while l-aMCI had worse functional performance (p = 0.007), a trend towards greater depressive symptoms (p = 0.05) and higher medial temporal lobe atrophy scores (p = 0.06). l-aMCI subjects were more likely than either pre-MCI or e-aMCI to progress to dementia over a mean follow-up period of 2.5 years (46.7 vs. 9.1 and 20.0%, respectively).
  
  
  CONCLUSIONS
  Clinical delineation of aMCI allows the differentiation of those likely to progress for better correlation to biomarker development.
authors.affiliation: Cognition and Memory Disorders Service, Department of Geriatric Medicine, Tan Tock Seng Hospital, Singapore.
authors.forename: M
authors.initials: M
authors.lastname: Chan
authors.forename: L
authors.initials: L
authors.lastname: Tay
authors.forename: M S
authors.initials: MS
authors.lastname: Chong