Effect of A/T/N imaging biomarkers on impaired odor identification in Alzheimer's disease

• Published in: Scientific reports 2020-07, Vol.10 (1), p.11556-11556, Article 11556
• Main Authors: Baek, Min Seok, Cho, Hanna, Lee, Hye Sun, Lee, Jae Hoon, Ryu, Young Hoon, Lyoo, Chul Hyoung
• Format: Article
• Language: English
• Subjects: 631/378; 692/617; Aged; Aged, 80 and over; Alzheimer Disease - complications; Alzheimer Disease - diagnostic imaging; Alzheimer Disease - metabolism; Alzheimer's disease; Amyloid; Amyloid beta-Peptides - metabolism; Aniline Compounds; Anosmia - etiology; Anosmia - metabolism; Biomarkers; Brain - diagnostic imaging; Brain Mapping; Carbolines; Cognitive ability; Correlation analysis; Female; Fluorine Radioisotopes; Humanities and Social Sciences; Humans; Identification; Image Processing, Computer-Assisted; Magnetic Resonance Imaging; Male; Medical imaging; Middle Aged; multidisciplinary; Neurodegeneration; Neurodegenerative diseases; Neuroimaging; Odor; Odorants; Odors; Olfaction Disorders - complications; Olfaction Disorders - diagnosis; Olfactory discrimination; Positron Emission Tomography Computed Tomography; Science; Science (multidisciplinary); Smell; Stilbenes; Tau protein; tau Proteins - metabolism
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/s41598-020-68504-2

Odor identification ability may serve as an important diagnostic biomarker in Alzheimer’s disease (AD). The aim of the study is to investigate the contribution of A/T/N neuroimaging biomarkers to impaired odor identification ability in the Alzheimer’s disease spectrum. In 127 participants, we compared A/T/N neuroimaging biomarkers between normosmia and hyposmia groups, and performed correlation analysis between the biomarkers and Cross-Cultural Smell Identification Test (CCSIT) scores. Additionally, path analysis for odor identification ability was performed using cognitive function as a mediator. In between-group comparison, individuals with hyposmia showed higher frequency of amyloid-β (Aβ) positivity, and lower neuropsychological test performance than those with normosmia. After correction for covariates including total cognition scores, there was no difference in the Aβ or tau burden between the normosmia and hyposmia groups, and no correlation between CCSIT scores and Aβ or tau burden. Meanwhile, cortical volumes in the lateral and medial temporal cortices were smaller in the hyposmia group and decreased with the worsening of CCSIT scores. Path analysis showed that only neurodegeneration had a direct effect on odor identification, while Aβ and tau burden contributed to odor identification with the mediation of cognition. In the Alzheimer’s disease spectrum, impaired odor identification ability may be attributable to neurodegeneration rather than the direct effect of Aβ or tau burden.