Effects of transcranial direct current stimulation and transcranial random noise stimulation on working memory and task-related EEG in major depressive disorder

O W Murphy; K E Hoy; D Wong; N W Bailey; P B Fitzgerald; R A Segrave

doi:10.1016/j.bandc.2023.106105

Effects of transcranial direct current stimulation and transcranial random noise stimulation on working memory and task-related EEG in major depressive disorder

Brain Cogn. 2023 Dec:173:106105. doi: 10.1016/j.bandc.2023.106105. Epub 2023 Nov 12.

Authors

O W Murphy¹, K E Hoy², D Wong³, N W Bailey⁴, P B Fitzgerald⁵, R A Segrave⁶

Affiliations

¹ Central Clinical School, Monash University, Clayton, VIC, Australia; Bionics Institute, East Melbourne, VIC, Australia. Electronic address: omurphy@bionicsinstitute.org.
² Central Clinical School, Monash University, Clayton, VIC, Australia; Bionics Institute, East Melbourne, VIC, Australia.
³ School of Psychology and Public Health, La Trobe University, Bundoora, VIC, Australia.
⁴ Central Clinical School, Monash University, Clayton, VIC, Australia; Monarch Research Institute Monarch Mental Health Group, Sydney, NSW, Australia; School of Medicine and Psychology, Australian National University, Canberra, ACT, Australia.
⁵ Monarch Research Institute Monarch Mental Health Group, Sydney, NSW, Australia; School of Medicine and Psychology, Australian National University, Canberra, ACT, Australia.
⁶ BrainPark, Turner Institute for Brain and Mental Health, Monash University, Clayton, VIC, Australia.

PMID: 37963422
DOI: 10.1016/j.bandc.2023.106105

Abstract

Objective: To compare effects of transcranial direct current stimulation (tDCS) and transcranial random noise stimulation with a direct-current offset (tRNS + DC-offset) on working memory (WM) performance and task-related electroencephalography (EEG) in individuals with Major Depressive Disorder (MDD).

Methods: Using a sham-controlled, parallel-groups design, 49 participants with MDD received either anodal tDCS (N = 16), high-frequency tRNS + DC-offset (N = 16), or sham stimulation (N = 17) to the left dorsolateral prefrontal cortex (DLPFC) for 20-minutes. The Sternberg WM task was completed with concurrent EEG recording before and at 5- and 25-minutes post-stimulation. Event-related synchronisation/desynchronisation (ERS/ERD) was calculated for theta, upper alpha, and gamma oscillations during WM encoding and maintenance.

Results: tDCS significantly increased parieto-occipital upper alpha ERS/ERD during WM maintenance, observed on EEG recorded 5- and 25-minutes post-stimulation. tRNS + DC-offset did not significantly alter WM-related oscillatory activity when compared to sham stimulation. Neither tDCS nor tRNS + DC-offset improved WM performance to a significantly greater degree than sham stimulation.

Conclusions: Although tDCS induced persistent effects on WM-related oscillatory activity, neither tDCS nor tRNS + DC-offset enhanced WM performance in MDD.

Significance: This reflects the first sham-controlled comparison of tDCS and tRNS + DC-offset in MDD. These findings directly contrast with evidence of tRNS-induced enhancements in WM in healthy individuals.

Keywords: Depression; EEG; Transcranial direct current stimulation (tDCS); Transcranial random noise stimulation (tRNS); Working memory.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Depressive Disorder, Major* / therapy
Electroencephalography
Humans
Memory, Short-Term / physiology
Prefrontal Cortex / physiology
Transcranial Direct Current Stimulation*