Majed Al-Otaibi, Melissa Lessard-Beaudoin, Christian-Alexandre Castellano, Denis Gris, Stephen C. Cunnane and Rona K. Graham* Pages 904 - 915 ( 12 )
Objective: Alzheimer disease (AD) is a chronic neurodegenerative disorder that affects millions of individuals worldwide. Symptoms include memory dysfunction and deficits in attention, planning, language, and overall cognitive function. Olfactory dysfunction is a common symptom of AD and evidence supports that it is an early marker. Furthermore, olfactory bulb and entorhinal cortex atrophy are well described in AD. However, in AD, no studies have assessed the olfactory cortex as a whole and if sex effects are observed. </p> Methods: Magnetic Resonance Imaging was used to scan 39 participants with an average age of 72 years and included men and women. AAL Single-Subject Atlas (implemented in PNEURO tool - PMOD 3.8) was used to determine the volume of the olfactory cortex and the hippocampus. Olfactory cortex volume was lower in both men and women AD cases compared with controls. This decrease was more apparent in the left olfactory cortex and was influenced by age. As expected, hippocampal volume was also significantly reduced in AD. However, this was only observed in the male cohort. A significant correlation was observed between levels of education and hippocampal volume in controls that were not detected in the AD participants. Asymmetry was observed in the olfactory cortex volume when comparing left and right volumes in both the control and AD participants, which was not observed in the hippocampus. </p> Results: These data highlight the importance of the role of olfactory cortical atrophy in the pathogenesis of AD and the interplay between the olfactory deficits and degeneration of olfactory regions in the brain.
Alzheimer disease, olfactory cortex, atrophy, brain asymmetry, hippocampus, magnetic resonance imaging.
University of Sheffield, Sheffield, England, Research Center on Aging, CIUSSS-IUGS de l’Estrie-CHUS, Sherbrooke, QC, Research Center on Aging, CIUSSS-IUGS de l’Estrie-CHUS, Sherbrooke, QC, Department of Pediatrics, University of Sherbrooke, Sherbrooke, QC, Research Center on Aging, CIUSSS-IUGS de l’Estrie-CHUS, Sherbrooke, QC, Research Center on Aging, CIUSSS-IUGS de l’Estrie-CHUS, Sherbrooke, QC