Effect of transcranial direct current stimulation with cognitive training on executive functions in healthy older adults: a secondary analysis from the ACT trial

Serkan Aksu; Aprinda Indahlastari; Andrew O'Shea; Michael Marsiske; Ronald Cohen; Gene E Alexander; Steven T DeKosky; Georg A Hishaw; Yunfeng Dai; Samuel S Wu; Adam J Woods

doi:10.1007/s11357-024-01455-y

Effect of transcranial direct current stimulation with cognitive training on executive functions in healthy older adults: a secondary analysis from the ACT trial

Geroscience. 2024 Nov 30. doi: 10.1007/s11357-024-01455-y. Online ahead of print.

Authors

Serkan Aksu^{1

2

3}, Aprinda Indahlastari^{4

5}, Andrew O'Shea^{4

5}, Michael Marsiske^{4

5}, Ronald Cohen^{4

5}, Gene E Alexander^{6

7}, Steven T DeKosky^{4

8}, Georg A Hishaw⁶, Yunfeng Dai⁹, Samuel S Wu⁹, Adam J Woods^{4

5}

Affiliations

¹ Center for Cognitive Aging and Memory, McKnight Brain Institute, University of Florida, 1225 Center Dr, PO Box 100165, Gainesville, FL, 32610, USA. serkanaksu@mu.edu.tr.
² Department of Clinical and Health Psychology, College of Public Health and Health Professions, University of Florida, 1225 Center Dr, PO Box 100165, Gainesville, FL, 32610, USA. serkanaksu@mu.edu.tr.
³ Department of Physiology, Faculty of Medicine, Muğla Sıtkı Koçman University, Muğla, Turkey. serkanaksu@mu.edu.tr.
⁴ Center for Cognitive Aging and Memory, McKnight Brain Institute, University of Florida, 1225 Center Dr, PO Box 100165, Gainesville, FL, 32610, USA.
⁵ Department of Clinical and Health Psychology, College of Public Health and Health Professions, University of Florida, 1225 Center Dr, PO Box 100165, Gainesville, FL, 32610, USA.
⁶ Department of Psychiatry, Neuroscience and Physiological Sciences Graduate Interdisciplinary Programs, and BIO5 Institute, University of Arizona and Arizona Alzheimer's Disease Consortium, Tucson, AZ, USA.
⁷ Department of Psychology and Evelyn F. McKnight Brain Institute, University of Arizona, Tucson, AZ, USA.
⁸ Department of Neurology, College of Medicine, University of Florida, Gainesville, FL, USA.
⁹ Department of Biostatistics, College of Public Health and Health Professions, College of Medicine, University of Florida, Gainesville, FL, USA.

PMID: 39614040
DOI: 10.1007/s11357-024-01455-y

Abstract

Cognitive aging has become a public health concern as the mean age of the population is ever-increasing. It is a naturalistic and common process of degenerative and compensatory changes that may result in neurocognitive disorders. While heterogeneous, cognitive aging mostly affects executive functions that may be associated with functional losses during activities of daily living. Cognition-oriented treatments like cognitive training and transcranial direct current stimulation (tDCS) have garnered considerable attention in the past few decades while the exact picture regarding their efficacy in healthy older adults has not been determined yet. The present paper aimed to evaluate the effects of a 3-month intervention of tDCS over the dorsolateral prefrontal cortex (DLPFC) with multimodal cognitive training on the Stroop test and Trail Making Tests A and B performance. One hundred and ninety-three healthy older adults from 2 sites were administered repeated sessions of active/sham tDCS with cognitive training. Baseline, post-intervention, and 1-year performance results between groups were compared using multiple linear regressions. Active tDCS resulted in better Stroop test performance at post-intervention (p = 0.033) but not at 1-year follow-up while no differences between groups were observed in Trail Making Tests A & B performance. The present results may correspond to a modest improvement in conflict monitoring, potentially due to modulation of prefrontal regions, without changing shifting performance. Further investigation is warranted to draw an interference regarding the subdomain-specific impact of repeated tDCS with multimodal cognitive training on executive functions.

Keywords: Brain stimulation; Cognitive training; Conflict monitoring; Executive functions; Older adults; TDCS; Transcranial direct current stimulation.