Abstract
Introduction: Several methods of improving cognitive performance have been identified. One is cognitive training (CT); another is transcranial direct current stimulation (tDCS). The design of this study and the choice of stimulation parameters were driven by findings from a meta-analysis (Pobric & Hulleman, 2021). The primary aim of this study was to assess whether a combination of multi-session tDCS and CT improves performance on a difficult visual search task beyond the improvement provided by CT alone. The study also tested generalisation to other tasks.
Method: This study examined the effect of 20 minutes, 2 mA HD-tDCS over right prefrontal cortex (rPFC), applied concurrently with visual search training in 5 consecutive sessions. 110 participants were recruited across three groups: active stimulation (n = 37), sham stimulation (n = 37), and no gear control who received CT only (n = 36). EEG recordings were obtained before and following the training protocol. In these sessions participants completed several transfer tasks: 1) Corsi Task, 2) T versus L Search Task, 3) Difficult Visual Search Task
Results: We report no significant effect of active HD-tDCS on any behavioural or EEG measures. There was a significant and very large effect of CT for all groups for various behavioural, eye-movement and EEG measures. Simply switching on the stimulator hindered performance for both HD-tDCS and sham groups, perhaps due to initial physical sensations of tDCS. Generalization effects were observed for both a near (T versus L search) and a far transfer, visuospatial memory task (Corsi Blocks).
Conclusion: Our study did not find any evidence that HD- tDCS over rPFC is effective in facilitating performance on visual search tasks involving naïve participants. When taken together with the meta-analysis, it emphasises the risks involved in applying non-invasive brain stimulation parameters to new tasks based on meta-analysis findings only.
Method: This study examined the effect of 20 minutes, 2 mA HD-tDCS over right prefrontal cortex (rPFC), applied concurrently with visual search training in 5 consecutive sessions. 110 participants were recruited across three groups: active stimulation (n = 37), sham stimulation (n = 37), and no gear control who received CT only (n = 36). EEG recordings were obtained before and following the training protocol. In these sessions participants completed several transfer tasks: 1) Corsi Task, 2) T versus L Search Task, 3) Difficult Visual Search Task
Results: We report no significant effect of active HD-tDCS on any behavioural or EEG measures. There was a significant and very large effect of CT for all groups for various behavioural, eye-movement and EEG measures. Simply switching on the stimulator hindered performance for both HD-tDCS and sham groups, perhaps due to initial physical sensations of tDCS. Generalization effects were observed for both a near (T versus L search) and a far transfer, visuospatial memory task (Corsi Blocks).
Conclusion: Our study did not find any evidence that HD- tDCS over rPFC is effective in facilitating performance on visual search tasks involving naïve participants. When taken together with the meta-analysis, it emphasises the risks involved in applying non-invasive brain stimulation parameters to new tasks based on meta-analysis findings only.
| Original language | English |
|---|---|
| Article number | P3.07 |
| Pages (from-to) | 533 |
| Number of pages | 1 |
| Journal | Brain Stimulation |
| Volume | 18 |
| Issue number | 1 |
| DOIs | |
| Publication status | Published - Jan 2025 |
| Event | 6th International Brain Stimulation Conference - Japan, Kobe, Japan Duration: 26 Feb 2025 → 3 Mar 2025 |