title: Central auditory dysfunction as a harbinger of Alzheimer dementia.
abstract: OBJECTIVE
  To confirm that central auditory dysfunction (CAD) may be a precursor to the onset of Alzheimer dementia (AD).
  
  
  METHODS
  Cohort study.
  
  
  METHODS
  Research study center.
  
  
  METHODS
  Two hundred seventy-four volunteers from a dementia surveillance cohort were followed up for as long as 4 years after undergoing complete audiometric assessment. Twenty-one received a consensus diagnosis of AD after a hearing test.
  
  
  METHODS
  The following 3 central auditory tests were performed: the Dichotic Sentence Identification, the Dichotic Digits, and the Synthetic Sentence Identification With Ipsilateral Competing Message.
  
  
  METHODS
  A new diagnosis of AD using the National Institute of Neurological and Communicative Diseases and Stroke-Alzheimer Disease and Related Disorders Association criteria at a consensus conference.
  
  
  RESULTS
  The mean scores on each CAD test were significantly poorer in the incident dementia group. Cox proportional hazards models with age as the time scale were used to estimate the hazard ratio for incident dementia based on CAD test results. After adjusting for educational level, the hazard ratio for incident dementia in people with severe CAD based on a Dichotic Sentence Identification in free report mode of less than 50% was 9.9 (95% confidence interval, 3.6-26.7).
  
  
  CONCLUSIONS
  Central auditory dysfunction is a precursor to AD. We recommend evaluation with CAD tests in older adults who report hearing difficulty. Those with severe CAD should receive a modified rehabilitation program and be considered for referral for neurologic evaluation.
authors.affiliation: Virginia Merrill Bloedel Hearing Research Center, Department of Otolaryngology-Head and Neck Surgery, University of Washington, P.O. Box 357923, Seattle, WA 98195-7923, USA. ggates@u.washington.edu
authors.forename: George A
authors.initials: GA
authors.lastname: Gates
authors.forename: Melissa L
authors.initials: ML
authors.lastname: Anderson
authors.forename: Susan M
authors.initials: SM
authors.lastname: McCurry
authors.forename: M Patrick
authors.initials: MP
authors.lastname: Feeney
authors.forename: Eric B
authors.initials: EB
authors.lastname: Larson
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000175:diagnosis / Q000453:epidemiology*; D001304:Auditory Diseases, Central / Q000453:epidemiology / Q000209:etiology*; D042241:Early Diagnosis; D005260:Female; D006320:Hearing Tests; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D016016:Proportional Hazards Models; D014481:United States / Q000453:epidemiology