title: Value of neuropsychological tests, neuroimaging, and biomarkers for diagnosing Alzheimer's disease in younger and older age cohorts.
abstract: OBJECTIVE
  To examine the influence of age on the value of four techniques for diagnosing Alzheimer's disease (AD).
  
  
  METHODS
  Observational cohort study.
  
  
  METHODS
  Alzheimer's Disease Neuroimaging Initiative.
  
  
  METHODS
  Individuals with mild cognitive impairment (MCI; n = 179), individuals with AD (n = 91), and normal controls (n = 105).
  
  
  METHODS
  Neuropsychological tests, structural magnetic resonance imaging (MRI), amyloid-beta and tau in cerebrospinal fluid (CSF), and [18F]fluorodeoxyglucose positron emission tomography (FDG-PET) for the diagnosis of MCI or AD. MCI was defined according to subjective memory complaints corroborated by an informant and an abnormal score on the delayed paragraph recall subtest of the Wechsler Memory Scale-Revised, a Mini-Mental State Examination score greater than 23, and a Clinical Dementia Rating score of 0.5. Participants with AD satisfied National Institute of Neurological and Communicative Diseases and Stroke/Alzheimer's Disease and Related Disorders Association criteria of probable AD.
  
  
  RESULTS
  Neuropsychological tests and MRI were the most informative techniques, with 84% and 82% correct classifications, respectively, and areas under the receiver operating characteristic curve (AUCs) of 0.93 (90% confidence interval (CI) = 0.91-0.95) and 0.88 (90% CI = 0.85-0.91). FDG-PET and CSF assessments had 76% and 73% correct classifications, respectively, (AUC = 0.77, 90% CI = 0.71-0.83; AUC = 0.77, 90% CI = 0.73-0.82). These figures increased slightly when the techniques were combined. All analyses were repeated for the younger (<75) and older (≥ 75) halves of the sample. FDG-PET and CSF assessment were substantially less informative in the older cohort, and they did not add diagnostic information when all techniques were combined.
  
  
  CONCLUSIONS
  Structural MRI and neuropsychological assessment are diagnostic methods of first choice if AD is suspected. CSF and FDG-PET add little to these diagnostic techniques, especially in older adults.
authors: Department of Neurology, Academic Medical Centre, University of Amsterdam, Amsterdam, the Netherlands. b.schmand@amc.nl
authors: Ben
authors: B
authors: Schmand
authors: Piet
authors: P
authors: Eikelenboom
authors: Willem A
authors: WA
authors: van Gool
mesh_terms: D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000175:diagnosis*; D016229:Amyloid beta-Peptides / Q000134:cerebrospinal fluid; D015415:Biomarkers / Q000134:cerebrospinal fluid; D002555:Cerebrospinal Fluid / Q000737:chemistry; D060825:Cognitive Dysfunction / Q000175:diagnosis*; D015331:Cohort Studies; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D009483:Neuropsychological Tests; D049268:Positron-Emission Tomography; D019275:Radiopharmaceuticals; D016875:tau Proteins / Q000134:cerebrospinal fluid
chemical_list: D016229:Amyloid beta-Peptides; D015415:Biomarkers; D019275:Radiopharmaceuticals; D016875:tau Proteins; D019788:Fluorodeoxyglucose F18