Disrupted Value-Directed Strategic Processing in Individuals with Mild Cognitive Impairment: Behavioral and Neural Correlates

Abstract

Value-directed strategic processing involves attending to higher-value information while inhibiting lower-value information. This preferential processing is relatively preserved in cognitively normal older adults but is impaired in individuals with dementia. No studies have investigated whether value-directed strategic processing is disrupted in earlier stages of cognitive decline, namely, mild cognitive impairment (MCI). The current study examined behavioral and EEG differences in value-directed strategic processing between 18 individuals with MCI and 18 cognitively normal older controls using a value-directed list learning task. Behaviorally, individuals with MCI recalled fewer total and high-value words compared to controls, but no group differences were observed in low-value word recall. Neurally, individuals with MCI had reduced theta synchronization relative to controls between 100 and 200 ms post-stimulus. Greater alpha desynchronization was observed for high- versus low-value words between 300 and 400 ms in controls but not in the MCI group. The groups showed some processing similarities, with greater theta synchronization for low-value words between 700 and 800 ms and greater alpha desynchronization for high-value words between 500 and 1100 ms. Overall, value-directed strategic processing was compromised in individuals with MCI on both behavioral and neural measures relative to controls. These findings add to the growing body of literature on differences between typical cognitive aging and MCI.

Alpha and theta oscillations on a visual strategic processing task in age-related hearing loss

“…This was not observed for the NH controls. We did not expect this given that our previous studies have not found similar differences between theta synchronization for high- versus low-value words in cognitively healthy adults ( Nguyen et al, 2020 ) and those with mild cognitive impairment ( Nguyen et al, 2022 ). Whether these findings are specific to the ARHL group needs further validation.…”

“…Overall, we found oscillatory activity in theta and alpha bands linked to strategic processing. Specifically, we found greater theta synchronization (more positive power relative to baseline) during processing of low-value relative to high-value words in frontal electrodes ( Nguyen et al, 2019 , 2020 , 2022 ). Extant literature suggests that frontal theta activity is linked to cognitive control in general [see ( Cavanagh and Frank, 2014 ) for a review] and is typically recorded at Fz and FPz electrodes [see ( Mitchell et al, 2008 )].…”

“…The selection of these electrode sites was guided by our previous work, as well as the literature, which shows greater prominence of theta band at frontal sites and alpha band at parietal sites ( Pfurtscheller and Lopes da Silva, 1999 ; Kawasaki et al, 2010 ; Cavanagh and Frank, 2014 ; Nguyen et al, 2019 , 2020 , 2022 ). Given that this is the first study examining ERSP correlates of value-directed strategic processing in ARHL, we decided to explore additional electrode sites, specifically prefrontal and centroparietal electrodes ( Mitchell et al, 2008 ; Nguyen et al, 2022 ). Change in power will be described as synchronization or desynchronization, depending on an increase or decrease in the power, respectively, relative to baseline.…”

“…Particularly measures linked to event-related spectral perturbations (ERSPs) capture both phase-locked and non-phase-locked spectral activity in the EEG signal ( Makeig, 1993 ; Makeig et al, 2004 ). Using a value-directed strategic processing task, our group examined ERSPs in the theta and alpha bands in both cognitively healthy controls ( Nguyen et al, 2019 , 2020 ) and older adults with mild cognitive impairment ( Nguyen et al, 2022 ). Overall, we found oscillatory activity in theta and alpha bands linked to strategic processing.…”

“…Guided by the literature, including emerging work on neural oscillations in ARHL, and our previous studies on value-directed strategic attention in cognitively healthy and impaired populations, we hypothesized that the mild ARHL group would show lower theta synchronization and alpha desynchronization relative to the control group. To clarify, given the lack of studies on theta ERSPs in ARHL, our hypothesis of lower theta synchronization in the ARHL relative to the control group was guided by findings of our previous study ( Nguyen et al, 2022 ), as well as expectation of poorer cognitive control in ARHL given that studies have shown poorer performance on cognitive control tasks in those with ARHL relative to NH controls ( Lin, 2011 ; Powell et al, 2022 ; Shende and Mudar, 2023 ). We also hypothesized greater theta synchronization for low- versus high-value words and greater alpha desynchronization for high- versus low-value words.…”