title: Association between olfaction and higher cortical functions in Alzheimer's disease, mild cognitive impairment, and healthy older adults.
abstract: BACKGROUND
  Neural regions important for smell are proximal and closely connected to cortical areas that have been strongly implicated in higher order functions of value-based decision making and emotional memory. The integrity of these neural regions are affected in aging and neurodegenerative conditions. Two specific predictions follow from these neuroanatomical arrangements-namely, that olfaction would be associated with value-based decision making and with emotional memory.
  
  
  METHODS
  To test these predictions, we measured these different capacities in participants with presumed varying degrees of integrity of the relevant brain structures: specifically, 13 patients with Alzheimer's disease, 8 patients with mild cognitive impairment, and 20 healthy older adults. The participants completed detailed tests of olfaction, value-based decision making, emotional memory, and general cognitive ability.
  
  
  RESULTS
  Olfactory functioning was significantly associated with emotional and nonemotional memory. The association was especially strong and consistent for memory recall with olfaction, explaining as much as 10% additional variance over and above general cognition. Olfactory functioning was not strongly or consistently associated with decision making over and above general cognition.
  
  
  CONCLUSIONS
  Olfaction is a strong predictor of memory recall. These findings may contribute to a better understanding of olfaction and specific cognitive domains known to be affected by aging and implicated in neurodegenerative disease.
authors.affiliation: a Department of Psychological and Brain Sciences , University of Iowa , Iowa City , IA , USA.
authors.forename: Amanda M
authors.initials: AM
authors.lastname: Ward
authors.affiliation: b Department of Psychology , Louisiana State University , Baton Rouge , LA , USA.
authors.forename: Matthew
authors.initials: M
authors.lastname: Calamia
authors.affiliation: a Department of Psychological and Brain Sciences , University of Iowa , Iowa City , IA , USA.
authors.forename: Erin
authors.initials: E
authors.lastname: Thiemann
authors.affiliation: a Department of Psychological and Brain Sciences , University of Iowa , Iowa City , IA , USA.
authors.forename: Jamie
authors.initials: J
authors.lastname: Dunlap
authors.affiliation: a Department of Psychological and Brain Sciences , University of Iowa , Iowa City , IA , USA.|c Department of Neurology , University of Iowa Carver College of Medicine , Iowa City , IA , USA.
authors.forename: Daniel
authors.initials: D
authors.lastname: Tranel
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology*; D000544:Alzheimer Disease / Q000503:physiopathology*; D060825:Cognitive Dysfunction / Q000503:physiopathology*; D003657:Decision Making / Q000502:physiology*; D004644:Emotions / Q000502:physiology*; D005260:Female; D006801:Humans; D007360:Intelligence / Q000502:physiology*; D008297:Male; D008568:Memory / Q000502:physiology*; D055696:Olfactory Perception / Q000502:physiology*
keywords: Decision making; Dementia; Emotions; Memory; Smell