title: Smell identification function and Alzheimer's disease: a selective review.
abstract: OBJECTIVE
  To provide an update of the recent studies on the olfactory function in Alzheimer's disease, with a focus on the olfactory identification function.
  
  
  RESULTS
  The studies reviewed here confirm previous reports on the poor olfactory function in Alzheimer's disease compared to health normal controls and also as a marker for conversion from mild cognitive impairment to Alzheimer's disease. Olfactory identification function has been associated with severity of illness, non-cognitive neuropsychiatric symptoms, and structural and functional MRI measures. There is a possible interaction of apolipoprotein E genotype with olfactory performance in Alzheimer's disease patients and those at risk for Alzheimer's disease. Usefulness of smell identification function in differentiating Alzheimer's disease patients from other types of dementia needs to be established.
  
  
  CONCLUSIONS
  The need for simple, inexpensive and non-invasive procedures for aiding in the diagnosis and understanding of Alzheimer's disease has led to theories and procedures examining the role of olfactory functions in Alzheimer's disease. Although there is increasing evidence for olfactory dysfunction in general and impaired odour identification in particular in Alzheimer's disease, additional larger and methodologically sound research is needed for testing its clinical utility in day-to-day clinical practice for early, accurate and differential diagnosis of Alzheimer's disease.
authors.affiliation: Psychiatry for the Elderly, Department of Health Sciences, University of Leicester, Leicester, UK.
authors.forename: Latha
authors.initials: L
authors.lastname: Velayudhan
mesh_terms: D000544:Alzheimer Disease / Q000150:complications / Q000503:physiopathology*; D006801:Humans; D000857:Olfaction Disorders / Q000175:diagnosis / Q000209:etiology / Q000503:physiopathology; D009833:Olfactory Pathways / Q000503:physiopathology*