Olfactory deficits and amyloid-β burden in Alzheimer's disease, mild cognitive impairment, and healthy aging: a PiB PET study.

Olfactory deficits and increased amyloid-β (Aβ) burden are observed in people with amnestic mild cognitive impairment (aMCI); both factors may be predictive of Alzheimer's disease (AD). We explored whether olfactory identification is related to in vivo measures of Aβ burden using Pittsburgh Compound B (PiB) PET. Nineteen control, 24 aMCI, and 20 AD participants completed an olfactory identification task and underwent PiB PET scanning. Control participants performed better on olfactory identification and showed lower PiB binding than aMCI patients. There was a significant correlation between both factors when pooling all groups together but not when considering each group separately. In addition, the olfactory identification score did not differ between aMCI participants who were PiB-positive and those who were PiB-negative. We conclude that AD-related olfactory identification deficits are not directly related to Aβ burden.