Roanoke College, Salem, Virginia, USA
Alzheimer’s Disease (AD) is a progressive, neurodegenerative disorder where two-thirds of the affected population are women. Along with cognitive impairments, AD is associated with behavioral changes such as aggression towards caretakers. The limbic system consists of various brain structures that play a role in emotions and behavioral reactions. Some of the limbic system-related areas are the amygdala, hippocampus, thalamus, corpus collosum (CC), and white matter (WM). Cognitive changes with AD can be measured using the clinical dementia rating (CDR) scale. Physical changes in living patients require brain imaging tools, such as Magnetic Resonance Imaging (MRI). As there is currently sparse research present for these areas relating to the female brain, we used clinical data and FreeSurfer-processed imaging data from an open-access database, OASIS-3, to explore the associations between dementia severity and the volume of the limbic system-related brain components in women. A control group consisted of participants with no dementia and multiple brain scans while comparison groups consisted of participants with a single brain scan and 1) no dementia 2) mild dementia or 3) moderate/severe dementia. Hemisphere differences with increasing CDR were found for the thalamus as well as simple hemisphere differences for the hippocampus, thalamus, and WM. When using age-matched controls and normalized volume data, the amygdala, hippocampus, thalamus, and CC volumes for subjects with AD were different than those in the control group, with the amygdala and hippocampus also showing statistically significant volume loss with increasing dementia severity. As the areas included in this study are related to the limbic system, this provides insight into the physical changes occurring in the brain of women with increasing AD, who often show changes in emotions. This can be an area to longitudinally explore whether there are associated behavioral changes as physical changes at the individual level occur over time.
Abbreviations: AD – Alzheimer’s Disease; CC – Corpus Collosum; CDR – Clinical Dementia Ratings; MRI – Magnetic Resonance Imaging; NFT– Neurofibrillary Tangles; WM – White Matter
Keywords: Magnetic Resonance Imaging; FreeSurfer; Sex Differences; Amygdala; Hippocampus; Thalamus