title: Performance-based measures of everyday function in mild cognitive impairment.
abstract: OBJECTIVE
  The view that everyday function is preserved in mild cognitive impairment may be problematic. The objectives of this study were to determine the magnitude of impairment in everyday function in patients with mild cognitive impairment and Alzheimer's disease using a novel sensitive performance-based measure (the UCSD Performance-Based Skills Assessment; UPSA), contrast it with use of an informant-based measure (the Alzheimer's Disease Cooperative Study-Activities of Daily Living Inventory; ADCS-ADL), and model the relationship between cognitive measures and the performance-based measure.
  
  
  METHODS
  Fifty cognitively normal elders, 26 patients who met criteria for amnestic mild cognitive impairment, and 22 patients who suffered from mild to moderate Alzheimer's disease were assessed on the UPSA, the ADCS-ADL, and a battery of neurocognitive tests.
  
  
  RESULTS
  Patients with mild cognitive impairment had significant impairments on the UPSA but not on the ADCS-ADL. The magnitude of the effect size between the cognitively healthy and the mild cognitive impairment group for the UPSA was large (d=0.86). A strong and significant relationship was observed between cognitive performances in speed (R(2)=0.37), episodic memory (R(2)=0.10), and semantic processing (R(2)=0.03) and UPSA score using multiple regression models. The psychometric properties of the UPSA were acceptable, as were its sensitivity and specificity in contrasts between cognitively normal elders and patients with mild cognitive impairment and between the latter group and patients with Alzheimer's disease.
  
  
  CONCLUSIONS
  These findings indicate that performance-based measures of function may be a sensitive tool in studies of Alzheimer's disease and mild cognitive impairment and suggest the need for a reconceptualization of the relationship between cognition and function in mild cognitive impairment so that they can be usefully aligned.
authors.affiliation: Litwin Zucker Center for Research in Alzheimer's Disease and Memory Disorders, Feinstein Institute for Medical Research, 350 Community Dr., Manhassett, NY 11030, USA. tgoldber@nshs.edu
authors.forename: Terry E
authors.initials: TE
authors.lastname: Goldberg
authors.forename: Jeremy
authors.initials: J
authors.lastname: Koppel
authors.forename: Lynda
authors.initials: L
authors.lastname: Keehlisen
authors.forename: Erica
authors.initials: E
authors.lastname: Christen
authors.forename: Ute
authors.initials: U
authors.lastname: Dreses-Werringloer
authors.forename: Concepcion
authors.initials: C
authors.lastname: Conejero-Goldberg
authors.forename: Marc L
authors.initials: ML
authors.lastname: Gordon
authors.forename: Peter
authors.initials: P
authors.lastname: Davies
mesh_terms: D000203:Activities of Daily Living / Q000523:psychology*; D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000523:psychology; D000704:Analysis of Variance; D003072:Cognition Disorders / Q000523:psychology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D011581:Psychological Tests; D011597:Psychomotor Performance; D012372:ROC Curve; D012044:Regression Analysis; D012720:Severity of Illness Index