Gauging Working Memory Capacity From Differential Resting Brain Oscillations in Older Individuals With A Wearable Device.

Soheil Borhani,Margaret R Kelly,Yang Jiang,Fengpei Yuan,Gregory A Jicha,Xiaopeng Zhao,Karah E Gottschalk

doi:10.3389/fnagi.2021.625006

Abstract

Working memory is a core cognitive function and its deficits is one of the most common cognitive impairments. Reduced working memory capacity manifests as reduced accuracy in memory recall and prolonged speed of memory retrieval in older adults. Currently, the relationship between healthy older individuals’ age-related changes in resting brain oscillations and their working memory capacity is not clear. Eyes-closed resting electroencephalogram (rEEG) is gaining momentum as a potential neuromarker of mild cognitive impairments. Wearable and wireless EEG headset measuring key electrophysiological brain signals during rest and a working memory task was utilized. This research’s central hypothesis is that rEEG (e.g., eyes closed for 90 s) frequency and network features are surrogate markers for working memory capacity in healthy older adults. Forty-three older adults’ memory performance (accuracy and reaction times), brain oscillations during rest, and inter-channel magnitude-squared coherence during rest were analyzed. We report that individuals with a lower memory retrieval accuracy showed significantly increased alpha and beta oscillations over the right parietal site. Yet, faster working memory retrieval was significantly correlated with increased delta and theta band powers over the left parietal sites. In addition, significantly increased coherence between the left parietal site and the right frontal area is correlated with the faster speed in memory retrieval. The frontal and parietal dynamics of resting EEG is associated with the “accuracy and speed trade-off” during working memory in healthy older adults. Our results suggest that rEEG brain oscillations at local and distant neural circuits are surrogates of working memory retrieval’s accuracy and processing speed. Our current findings further indicate that rEEG frequency and coherence features recorded by wearable headsets and a brief resting and task protocol are potential biomarkers for working memory capacity. Additionally, wearable headsets are useful for fast screening of cognitive impairment risk.

Highlights

Visual working memory plays pivotal roles in many daily goaldirected activities, such as searching for a car in a parking lot or driving
The findings suggest that neural dynamics underlying accuracy are different from those undeserving memory retrieval speed
The frontal and posterior dynamics of resting EEG is associated with the “accuracy and speed trade-off ” during working memory in healthy older adults

Summary

Introduction

Visual working memory plays pivotal roles in many daily goaldirected activities, such as searching for a car in a parking lot or driving. Recent advances in machine learning algorithms and wireless technology have allowed for wearable EEGs to gain renewed traction as a means to measure brain activity (Jiang et al, 2017; Abiri et al, 2019b). Analyzing event-related potentials (ERPs), which is the averaged EEG brain response onset to a psychological event (e.g., attentional vigilance or memory retrieval), offers a brain imaging technique to gauge cognitive processes (McBride et al, 2012; Li et al, 2017; Abiri et al, 2019a; Borhani et al, 2019; Jiang et al, 2021)). One such disadvantage is that wearable EEGs are more susceptible to excessive body movement that can cause channel noise and artifacts in the recorded EEG signals, which can negatively impact the quality of the task-induced signals

Objectives

Methods

Results

Conclusion