So just to give you a little bit of background, so while the associations of amyloid beta with regional cortical thickness and cognition are well studied among the general aging population, little is actually known about these associations in the oldest old, however. So we know that very little is, for example, known about these associations in especially the diverse populations of the oldest old...
So just to give you a little bit of background, so while the associations of amyloid beta with regional cortical thickness and cognition are well studied among the general aging population, little is actually known about these associations in the oldest old, however. So we know that very little is, for example, known about these associations in especially the diverse populations of the oldest old. And also we know that the entorhinal cortex, it is an important structure for memory and is also known as the gateway to the hippocampus. It is one of the earliest regions to be vulnerable to Alzheimer’s disease pathology as well. And neurodegeneration of the medial temporal lobe is strongly predictive of memory decline in aging in general. And however, in this study, we tested whether amyloid beta is associated with medial temporal lobe regional cortical thickness or regional thickness and volumes, as well as verbal episodic memory in the oldest old. So it was interesting. What we found was that higher amyloid beta was associated with lower right entorhinal cortical thickness. However, we did not find that association between amyloid beta and left entorhinal cortical thickness. We also did not find an association between amyloid beta and left or right parahippocampal cortical thickness and nor with hippocampal volumes. And as expected, higher amyloid beta was associated with lower verbal episodic memory performance. Also, as expected, greater right entorhinal cortical thickness was also associated with better memory performance or in episodic memory performance. And when we performed a mediation model with entorhinal cortical thickness as a mediator between amyloid and memory, there was only a direct effect of amyloid beta on memory performance. However, we did not find this indirect effect of where entorhinal cortical thickness or right entorhinal cortical thickness would mediate the association between amyloid and memory performance. So this might suggest that the impact of amyloid beta on memory is not through entorhinal cortical thickness, at least in the oldest old, and it might be acting directly on memory performance or through other mechanisms such as tau pathology. However, entorhinal cortical thickness might have its own independent effects on memory performance, which might be independent of amyloid beta burden. From our findings, it seems that both imaging markers, amyloid beta, and entorhinal cortical thickness are important markers to predict memory outcomes in the oldest old, even if amyloid is not acting through entorhinal cortical thickness to affect memory impairment in the oldest old. It also suggests that it is important to understand these markers as the temporal progression might be impacting the older population differentially from the general aging population. So to study these markers longitudinally and also to uncover any early predictors of amyloid beta and entorhinal cortical structure, which might be not just the regular kind of factors that would impact amyloid beta, such as genetic predispositions, but it might be other modifiable types of factors that might be involved. And since amyloid beta and regional medial temporal lobe structure are not the only two contributors to the development of Alzheimer’s disease and related dementias, it suggests that we should be a little bit more comprehensive or more comprehensive in the types of imaging markers we want to include while investigating these pathways through which cognition is impacted and the oldest old. And hopefully through these studies or these types of studies, we can be a little bit more informed on the types of interventions and approaches we would need to take to delay and prevent Alzheimer’s disease in the oldest old even.
This transcript is AI-generated. While we strive for accuracy, please verify this copy with the video.
