%0 Journal Article %J J Alzheimers Dis %D 2018 %T Odor Identification Ability Predicts PET Amyloid Status and Memory Decline in Older Adults. %A Kreisl, William Charles %A Jin, Peng %A Lee, Seonjoo %A Dayan, Ezra R %A Vallabhajosula, Shankar %A Pelton, Gregory %A Luchsinger, Jose A %A Pradhaban, Gnanavalli %A Devanand, D P %X

BACKGROUND: Odor identification deficits occur in Alzheimer's disease (AD), as measured by the 40-item University of Pennsylvania Smell Identification Test (UPSIT).

OBJECTIVE: To determine if UPSIT scores predict amyloid-β (Aβ) status, determined by 11C-Pittsburgh Compound B PET. We also compared UPSIT scores to Aβ status in predicting future memory decline.

METHODS: Subjects were recruited into a longitudinal clinical prediction study. We analyzed data from those who had UPSIT, cognitive testing, PIB PET, and at least 12 months' clinical follow-up. Forty-six amnestic mild cognitive impairment patients and 25 cognitively normal controls were included. Amyloid-positivity was defined as composite PIB standardized uptake value ratio >1.5. Logistic regression and Receiver Operating Characteristic Curve analyses tested the predictive utility of impaired olfaction (defined as UPSIT score <35) and amyloid-positivity for memory decline.

RESULTS: High UPSIT scores predicted absence of amyloidosis on PET, with negative predictive value of 100%. Positive predictive value of low UPSIT scores on positive Aβ status was only 41%. Both low UPSIT score (OR = 4.301, 95% CI = 1.248, 14.821, p = 0.021) and positive PET scan (OR = 20.898, 95% CI = 2.222, 196.581, p = 0.008) predicted memory decline.

CONCLUSION: Individuals with high UPSIT scores are less likely to have cerebral amyloidosis or experience memory decline. Therefore, UPSIT has potential as a screening tool to determine utility of Aβ PET in clinical practice or enrollment in clinical trials. Low UPSIT score is a non-specific marker of neurodegeneration that could indicate further workup in patients with memory complaints.

%B J Alzheimers Dis %V 62 %P 1759-1766 %8 2018 %G eng %N 4 %1 http://www.ncbi.nlm.nih.gov/pubmed/29614678?dopt=Abstract %R 10.3233/JAD-170960