title: Validation and diagnostic accuracy of the Alzheimer's questionnaire.
abstract: BACKGROUND
  accurately identifying individuals with cognitive impairment is difficult. Given the time constraints that many clinicians face, assessment of cognitive status is often not undertaken. The intent of this study is to determine the diagnostic accuracy of the Alzheimer's questionnaire (AQ) in identifying individuals with mild cognitive impairment (MCI) and AD.
  
  
  METHODS
  utilising a case-control design, 300 [100 AD, 100 MCI, 100 cognitively normal (CN)] older adults between the ages of 53 and 93 from a neurology practice and a brain donation programme had the AQ administered to an informant. Diagnostic accuracy was assessed through receiver-operating characteristic analysis, which yielded sensitivity, specificity and area under the curve (AUC).
  
  
  RESULTS
  the AQ demonstrated high sensitivity and specificity for detecting MCI [89.00 (81.20-94.40)]; [91.00 (83.60-65.80)] and AD [99.00 (94.60-100.00)]; [96.00 (90.10-98.90)]. AUC values also indicated high diagnostic accuracy for both MCI [0.95 (0.91-0.97)] and AD [0.99 (0.96-1.00)]. Internal consistency of the AQ was also high (Cronbach's alpha = 0.89).
  
  
  CONCLUSIONS
  the AQ is a valid informant-based instrument for identifying cognitive impairment, which could be easily implemented in a clinician's practice. It has high sensitivity and specificity in detecting both MCI and AD and allows clinicians to quickly and accurately assess individuals with reported cognitive problems.
authors.affiliation: Cleo Roberts Center for Clinical Research, Banner Sun Health Research Institute, 10515 W. Santa Fe Drive, Sun City, AZ 85351, USA.
authors.forename: Michael
authors.initials: M
authors.lastname: Malek-Ahmadi
authors.forename: Kathryn
authors.initials: K
authors.lastname: Davis
authors.forename: Christine
authors.initials: C
authors.lastname: Belden
authors.forename: Brecken
authors.initials: B
authors.lastname: Laizure
authors.forename: Sandra
authors.initials: S
authors.lastname: Jacobson
authors.forename: Roy
authors.initials: R
authors.lastname: Yaari
authors.forename: Upinder
authors.initials: U
authors.lastname: Singh
authors.forename: Marwan N
authors.initials: MN
authors.lastname: Sabbagh
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000175:diagnosis* / Q000523:psychology; D000704:Analysis of Variance; D001130:Arizona; D016022:Case-Control Studies; D003071:Cognition; D060825:Cognitive Dysfunction / Q000175:diagnosis* / Q000523:psychology; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D012372:ROC Curve; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D011795:Surveys and Questionnaires