title: Global clinical dementia rating of 0.5 in MCI masks variability related to level of function.
abstract: OBJECTIVE
  To evaluate whether ratings on Clinical Dementia Rating (CDR) items related to instrumental activities of daily living (IADL) are associated with cognitive or brain morphometric characteristics of participants with mild cognitive impairment (MCI) and global CDR scores of 0.5.
  
  
  METHODS
  Baseline cognitive and morphometric data were analyzed for 283 individuals with MCI who were divided into 2 groups (impaired and intact) based on their scores on the 3 CDR categories assessing IADL. Rates of progression to Alzheimer disease (AD) over 2 years were also compared in the 2 groups.
  
  
  RESULTS
  The impaired IADL MCI group showed a more widespread pattern of gray matter loss involving frontal and parietal regions, worse episodic memory and executive functions, and a higher percentage of individuals progressing to AD than the relatively intact IADL MCI group.
  
  
  CONCLUSIONS
  The results demonstrate the importance of considering functional information captured by the CDR when evaluating individuals with MCI, even though it is not given equal weight in the assignment of the global CDR score. Worse impairment on IADL items was associated with greater involvement of brain regions beyond the mesial temporal lobe. The conventional practice of relying on the global CDR score as currently computed underutilizes valuable IADL information available in the scale, and may delay identification of an important subset of individuals with MCI who are at higher risk of clinical decline.
authors.affiliation: Department of Psychology, National Taiwan University, Taipei, 10617 Taiwan. ychang@ntu.edu.tw
authors.forename: Y-L
authors.initials: YL
authors.lastname: Chang
authors.forename: M W
authors.initials: MW
authors.lastname: Bondi
authors.forename: L K
authors.initials: LK
authors.lastname: McEvoy
authors.forename: C
authors.initials: C
authors.lastname: Fennema-Notestine
authors.forename: D P
authors.initials: DP
authors.lastname: Salmon
authors.forename: D
authors.initials: D
authors.lastname: Galasko
authors.forename: D J
authors.initials: DJ
authors.lastname: Hagler
authors.forename: A M
authors.initials: AM
authors.lastname: Dale
mesh_terms: D000203:Activities of Daily Living; D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D001921:Brain / Q000473:pathology*; D016009:Chi-Square Distribution; D003072:Cognition Disorders / Q000175:diagnosis* / Q000503:physiopathology*; D018450:Disease Progression; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008609:Mental Status Schedule; D008875:Middle Aged; D009483:Neuropsychological Tests; D011795:Surveys and Questionnaires