Patterns of olfactory functional networks in Parkinson's disease dementia and Alzheimer's dementia

• Published in: Neurobiology of aging 2020-05, Vol.89, p.63-70
• Main Authors: Lee, Yang Hyun, Bak, Yunjin, Park, Chang-hyun, Chung, Seok Jong, Yoo, Han Soo, Baik, Kyoungwon, Jung, Jin Ho, Sohn, Young H., Shin, Na-Young, Lee, Phil Hyu
• Format: Article
• Language: English
• Subjects: Alzheimer's dementia; Functional magnetic resonance imaging; Functional network; Olfaction; Parkinson's disease dementia
• ISSN: 0197-4580; 1558-1497
• DOI: 10.1016/j.neurobiolaging.2019.12.021

Hyposmia is common in Alzheimer's dementia (AD) and Parkinson's disease dementia (PDD). We evaluated the pattern of olfactory functional connectivity (FC) in AD and PDD to uncover neural correlates that are related to olfactory dysfunction. This study enrolled 57 patients with AD and PDD and 25 control subjects. Using a seed-based approach, we compared the resting-state network from the seed-region-of-interest in the olfactory bulb, olfactory tract, piriform cortex, and orbitofrontal cortex (OFC) between groups. The PDD group showed lower FC with striatal-thalamic-frontal regions from the olfactory bulb than the AD group. The PDD group showed lower FC from left OFC with striatal-frontal regions and lower FC from right OFC with left fronto-temporal areas than the AD group. In a correlation analysis, the FC from left OFC with right insula that differed between the PDD and control groups was positively correlated with olfactory function. The present study demonstrated that this distinct olfactory functional network pattern may represent different neural mechanisms for olfactory dysfunction in AD and PDD. •PDD showed lower olfactory bulb FC with striatal-thalamic-frontal regions than AD.•PDD exhibited lower orbitofrontal FC with striatal-frontal regions than AD.•Olfactory function was positively correlated with orbitofrontal FC in PDD.•This FC pattern may represent different neural mechanisms for olfactory dysfunction in AD and PDD.