Toward methodologies for motor imagery enhancement: a tDCS-BCI study

ABSTRACT

Motor imagery (MI) becomes a powerful rehabilitation tool, particularly when combined with brain–computer interfaces (BCI). Therefore, methods to improve MI accuracy are a trending topic in the BCI field. Here, we examined the effects of transcranial direct current stimulation (tDCS) and MI priming on the MI signature in an EEG-based MI-BCI triple-blind study. Thirty healthy younger adults participated in this study and were designated to one of two priming groups: A bimanual tracking task and a MI task as primers for MI-BCI. During the performance of the primer task, participants received anodal and sham tDCS in two randomized sessions with a one-week wash-out period between sessions. Subsequently, participants performed an EEG-driven BCI-MI task. EEG time–frequency analyses revealed that desynchronization of the Beta Region precedes desynchronization in the Alpha Region, implying that the Beta frequency band might be best-suited to extract MI signatures as it could lead to faster MI-BCI. Contrary to our hypotheses, no effect of tDCS or priming task on EEG activity during the BCI-MI task was found. Future research should carefully consider the added value of tDCS and priming tasks BCI performance improvement. Electric field modeling studies and high-definition tDCS motor cortex stimulation might be promising avenues.

KEYWORDS:

• Motor imagery
• tDCS
• brain–computer interfaces
• EEG
• signal processing
• neurostimulation

Acknowledgements

This work was supported by the Incoming Mobility Fund of Hasselt University (BOF21KV04); MACbiolDi2 (INTERREG program MAC2/1.1b/352); the FWO (Fonds Wetenschappelijk Onderzoek/Research Fundation of Flanders) G1129923N.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data availability statement

The data that support the findings of this study are available upon reasonable request by contacting the corresponding author, Diego Andrés Blanco-Mora, upon reasonable request.

Additional information

Funding

This work was supported by the Incoming Mobility Fund of Hasselt University (BOF21KV04); MACbiolDi2 (INTERREG program MAC2/1.1b/352); the FWO (Fonds Wetenschappelijk Onderzoek/Research Fundation of Flanders) G1129923N.