title: Olfaction and apathy in Alzheimer's disease, mild cognitive impairment, and healthy older adults.
abstract: OBJECTIVE
  Apathy is a prevalent neuropsychiatric manifestation in individuals with Alzheimer's disease (AD) that is associated with decreased social functioning and increased caregiver burden. Olfactory deficits are also commonly observed in AD, and prior work has indicated a link between increased apathy and olfactory dysfunction in individuals with Parkinson's disease. Here, we examined odor identification performance in patients with probable AD (n = 172), individuals with mild cognitive impairment (MCI; n = 112), and neurologically and psychiatrically healthy older adults (n = 132) and its relation to apathy, depression, and overall psychopathology.
  
  
  METHODS
  Participants were administered the Sniffin' Sticks odor identification test and measures assessing severity of apathy, depression, and overall neuropsychiatric symptomatology.
  
  
  RESULTS
  Consistent with previous research, AD and MCI patients were significantly worse at identifying odors than healthy older adults. Additionally, a sex by diagnosis interaction was observed. AD patients had significantly higher levels of apathy relative to MCI and control participants. Of note, across the entire sample odor identification deficits were correlated with level of apathy at the level of p < 0.01, but not with depression or neuropsychiatric symptom severity, when controlling for Mini-Mental State Examination (MMSE) score.
  
  
  CONCLUSIONS
  Collectively, these data suggest that olfactory disturbance and apathy in AD may result from the progression of disease pathology in shared neural substrates.
authors: Department of Psychology, Temple University, Philadelphia, PA, USA. sarah.seligman@temple.edu
authors: Sarah C
authors: SC
authors: Seligman
authors: Vidyulata
authors: V
authors: Kamath
authors: Tania
authors: T
authors: Giovannetti
authors: Steven E
authors: SE
authors: Arnold
authors: Paul J
authors: PJ
authors: Moberg
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000503:physiopathology* / Q000523:psychology; D057565:Apathy / Q000502:physiology*; D060825:Cognitive Dysfunction / Q000503:physiopathology* / Q000523:psychology; D003863:Depression / Q000523:psychology; D005260:Female; D006304:Health Status; D006801:Humans; D008297:Male; D000857:Olfaction Disorders / Q000175:diagnosis* / Q000523:psychology; D012720:Severity of Illness Index; D017678:Sex Distribution
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