title: Central auditory function in early Alzheimer's disease and in mild cognitive impairment.
abstract: OBJECTIVE
  to investigate auditory function in subjects with early Alzheimer's disease, mild cognitive impairment and with subjective memory complaints, in search of signs of central auditory processing dysfunction even in early stages of cognitive impairment.
  
  
  METHODS
  a consecutive group of men and women, referred to the Memory Clinic at the Karolinska University Hospital, was approached for inclusion in this prospective study. One hundred and thirty-six subjects, mean age 64 years (range 50-78 years), diagnosed with Alzheimer's disease (n = 43), mild cognitive impairment (n = 59) or with subjective memory complaints (n = 34), were included.
  
  
  METHODS
  auditory function was assessed with pure tone audiometry, speech perception in quiet and in background noise and dichotic digits tests with two or three digits.
  
  
  RESULTS
  pure tone audiometry and speech perception scores in quiet and in background noise were normal for age and without between-group differences. Dichotic digits tests showed strongly significant differences between the three groups, where the Alzheimer's disease group performed significantly poorer than the other two groups, with the mild cognitive impairment group in an intermediate position.
  
  
  CONCLUSIONS
  our results demonstrate that central auditory processing dysfunction is highly evident in subjects with Alzheimer's disease, and to a considerable extent even in subjects with mild cognitive impairment.
authors.affiliation: Department of Hearing and Balance, Karolinska University Hospital, Stockholm, Sweden. esma.idrizbegovic@karolinska.se
authors.forename: Esma
authors.initials: E
authors.lastname: Idrizbegovic
authors.forename: Christina
authors.initials: C
authors.lastname: Hederstierna
authors.forename: Martin
authors.initials: M
authors.lastname: Dahlquist
authors.forename: Charlotta
authors.initials: C
authors.lastname: Kämpfe Nordström
authors.forename: Vesna
authors.initials: V
authors.lastname: Jelic
authors.forename: Ulf
authors.initials: U
authors.lastname: Rosenhall
mesh_terms: D000161:Acoustic Stimulation; D000368:Aged; D000544:Alzheimer Disease / Q000150:complications* / Q000503:physiopathology / Q000523:psychology; D000704:Analysis of Variance; D001301:Audiometry, Pure-Tone; D001304:Auditory Diseases, Central / Q000209:etiology* / Q000503:physiopathology / Q000523:psychology; D001306:Auditory Pathways / Q000503:physiopathology*; D001307:Auditory Perception; D001309:Auditory Threshold; D003071:Cognition; D003072:Cognition Disorders / Q000209:etiology* / Q000523:psychology; D004007:Dichotic Listening Tests; D005260:Female; D006801:Humans; D008297:Male; D008568:Memory; D008875:Middle Aged; D009622:Noise / Q000009:adverse effects; D010470:Perceptual Masking; D011446:Prospective Studies; D012720:Severity of Illness Index; D013067:Speech Perception; D013548:Sweden