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Olfactory Impairment in Presymptomatic Alzheimer's Disease
Author(s) -
Wilson Robert S.,
Arnold Steven E.,
Schneider Julie A.,
Boyle Patricia A.,
Buchman Aron S.,
Bennett David A.
Publication year - 2009
Publication title -
annals of the new york academy of sciences
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.712
H-Index - 248
eISSN - 1749-6632
pISSN - 0077-8923
DOI - 10.1111/j.1749-6632.2009.04013.x
Subject(s) - dementia , disease , olfaction , episodic memory , cognition , memory impairment , alzheimer's disease , psychology , cognitive decline , medicine , audiology , psychiatry , neuroscience
Alzheimer's disease (AD) impairs olfaction, but it is uncertain how early this occurs in the disease process and whether the effect can be accounted for by other behavioral or genetic markers of the disease. We administered the Brief Smell Identification Test (BSIT) to 471 older people without dementia or cognitive impairment who then completed annual clinical evaluations and brain autopsy at death. BSIT score was associated with more rapid decline in episodic memory and with increased risk of developing incident mild cognitive impairment (MCI), even after controlling for baseline level of episodic memory and possession of an apolipoprotein E ɛ4 allele. In 34 people who died without evidence of cognitive impairment, lower BSIT score was associated with higher level of AD pathology, even after controlling for ɛ4 and for level of episodic memory function when olfaction was assessed. These analyses suggest that among older people without clinical manifestations of AD or MCI, olfactory dysfunction is related to both the level of AD pathology in the brain and the risk of subsequently developing prodromal symptoms of the disease, and that these associations persist after accounting for the effects of other recognized behavioral and genetic markers of the disease.