Hostname: page-component-7479d7b7d-m9pkr Total loading time: 0 Render date: 2024-07-15T00:32:55.329Z Has data issue: false hasContentIssue false

6 Adjunctive Transcranial Direct Current Stimulation and Cognitive Training Alters Default Mode and Frontoparietal Control Network Connectivity in Older Adults

Published online by Cambridge University Press:  21 December 2023

Hanna K Hausman*
Affiliation:
University of Florida, Gainesville, FL, USA.
Jessica N Kraft
Affiliation:
University of Florida, Gainesville, FL, USA.
Cheshire Hardcastle
Affiliation:
University of Florida, Gainesville, FL, USA.
Nicole D Evangelista
Affiliation:
University of Florida, Gainesville, FL, USA.
Emanuel M Boutzoukas
Affiliation:
University of Florida, Gainesville, FL, USA.
Andrew O’Shea
Affiliation:
University of Florida, Gainesville, FL, USA.
Alejandro Albizu
Affiliation:
University of Florida, Gainesville, FL, USA.
Emily J Van Etten
Affiliation:
University of Arizona, Tucson, AZ, USA
Pradyumna K Bharadwaj
Affiliation:
University of Arizona, Tucson, AZ, USA
Hyun Song
Affiliation:
University of Arizona, Tucson, AZ, USA
Samantha G Smith
Affiliation:
University of Arizona, Tucson, AZ, USA
Eric S Porges
Affiliation:
University of Florida, Gainesville, FL, USA.
Georg A Hishaw
Affiliation:
University of Arizona, Tucson, AZ, USA
Samuel Wu
Affiliation:
University of Florida, Gainesville, FL, USA.
Steven DeKosky
Affiliation:
University of Florida, Gainesville, FL, USA.
Gene E Alexander
Affiliation:
University of Arizona, Tucson, AZ, USA
Michael Marsiske
Affiliation:
University of Florida, Gainesville, FL, USA.
Ronald A Cohen
Affiliation:
University of Florida, Gainesville, FL, USA.
Adam J Woods
Affiliation:
University of Florida, Gainesville, FL, USA.
*
Correspondence: Hanna K. Hausman, Department of Clinical and Health Psychology, University of Florida, hanna.hausman@phhp.ufl.edu
Rights & Permissions [Opens in a new window]

Abstract

Core share and HTML view are not available for this content. However, as you have access to this content, a full PDF is available via the ‘Save PDF’ action button.
Objective:

Aging is associated with disruptions in functional connectivity within the default mode (DMN), frontoparietal control (FPCN), and cingulo-opercular (CON) resting-state networks. Greater within-network connectivity predicts better cognitive performance in older adults. Therefore, strengthening network connectivity, through targeted intervention strategies, may help prevent age-related cognitive decline or progression to dementia. Small studies have demonstrated synergistic effects of combining transcranial direct current stimulation (tDCS) and cognitive training (CT) on strengthening network connectivity; however, this association has yet to be rigorously tested on a large scale. The current study leverages longitudinal data from the first-ever Phase III clinical trial for tDCS to examine the efficacy of an adjunctive tDCS and CT intervention on modulating network connectivity in older adults.

Participants and Methods:

This sample included 209 older adults (mean age = 71.6) from the Augmenting Cognitive Training in Older Adults multisite trial. Participants completed 40 hours of CT over 12 weeks, which included 8 attention, processing speed, and working memory tasks. Participants were randomized into active or sham stimulation groups, and tDCS was administered during CT daily for two weeks then weekly for 10 weeks. For both stimulation groups, two electrodes in saline-soaked 5x7 cm2 sponges were placed at F3 (cathode) and F4 (anode) using the 10-20 measurement system. The active group received 2mA of current for 20 minutes. The sham group received 2mA for 30 seconds, then no current for the remaining 20 minutes.

Participants underwent resting-state fMRI at baseline and post-intervention. CONN toolbox was used to preprocess imaging data and conduct region of interest (ROI-ROI) connectivity analyses. The Artifact Detection Toolbox, using intermediate settings, identified outlier volumes. Two participants were excluded for having greater than 50% of volumes flagged as outliers. ROI-ROI analyses modeled the interaction between tDCS group (active versus sham) and occasion (baseline connectivity versus postintervention connectivity) for the DMN, FPCN, and CON controlling for age, sex, education, site, and adherence.

Results:

Compared to sham, the active group demonstrated ROI-ROI increases in functional connectivity within the DMN following intervention (left temporal to right temporal [T(202) = 2.78, pFDR < 0.05] and left temporal to right dorsal medial prefrontal cortex [T(202) = 2.74, pFDR < 0.05]. In contrast, compared to sham, the active group demonstrated ROI-ROI decreases in functional connectivity within the FPCN following intervention (left dorsal prefrontal cortex to left temporal [T(202) = -2.96, pFDR < 0.05] and left dorsal prefrontal cortex to left lateral prefrontal cortex [T(202) = -2.77, pFDR < 0.05]). There were no significant interactions detected for CON regions.

Conclusions:

These findings (a) demonstrate the feasibility of modulating network connectivity using tDCS and CT and (b) provide important information regarding the pattern of connectivity changes occurring at these intervention parameters in older adults. Importantly, the active stimulation group showed increases in connectivity within the DMN (a network particularly vulnerable to aging and implicated in Alzheimer’s disease) but decreases in connectivity between left frontal and temporal FPCN regions. Future analyses from this trial will evaluate the association between these changes in connectivity and cognitive performance post-intervention and at a one-year timepoint.

Type
Poster Session 07: Developmental | Pediatrics
Copyright
Copyright © INS. Published by Cambridge University Press, 2023