Schedule of Events | Symposia

Spatiotemporal episodic memory decline in MCI and Alzheimer’s disease is associated with parietal alpha/beta dysregulation

Poster Session B - Sunday, March 30, 2025, 8:00 – 10:00 am EDT, Back Bay Ballroom/Republic Ballroom

Sang-Eon Park¹ (9sang9@gmail.com), Maria Jieun Hwang¹, Jeonghyun Lee¹, So Yeon Jeon², Sang Ah Lee¹; ¹Department of Brain and Cognitive Sciences, Seoul National University, Seoul, Korea, ²Department of Psychiatry, Chungnam National University Hospital, Daejeon, Republic of Korea

Our previous studies reported that episodic memory decline in Alzheimer’s disease (AD) was more severe in the “where” and “when” components compared to “what” memory. In this study, we extended the investigation to mild cognitive impairment (MCI) patients, to test its potential application for predicting signs of memory impairment in a high-risk group who may be at an early stage of AD. 60 older participants (31 MCI with 19 amyloid-beta positive and 9 negative, 19 AD, 10 control; ages 62-86) performed a scene-based episodic memory task testing “what”, “where”, and “when” components while recording scalp EEG. All episodic memory components showed memory decline in MCI and AD patients but the “what” memory was relatively preserved compared to spatiotemporal (“where” and “when”) memory. Moreover, MCI patients without amyloid beta (MCI-) showed better spatiotemporal memory while MCI patients with amyloid beta (MCI+) and AD patients failed to perform above chance level. We found that alpha and beta power (10-30Hz) in parietal EEG channels was associated with this deficit during memory retrieval: specifically, unlike healthy controls and MCI- patients, alpha and beta did not decrease from baseline in MCI+ and AD patients. This is consistent with the interpretation that amyloid plaques in MCI+ and AD patients induce neural hyperactivation and disturbance of functional connectivity across brain networks. We speculate that spatiotemporal memory may be particularly sensitive to such neural dysfunction due to its heavy dependence on the cortico-hippocampal memory network.

Topic Area: LONG-TERM MEMORY: Development & aging