The effect of transcranial direct current stimulation on language processing in healthy individuals

In the recent years, transcranial direct current stimulation (tDCS) has been recognized by the academic and clinical community as a very promising tool. Supposedly, this non-invasive, safe and tolerable method may enhance the positive effect of neurorehabilitation and, specifically, language therapy in post-stroke patients. However, it is still debatable whether tDCS can also enhance language processing in neurologically healthy individuals (Westwood et al., 2017). We have investigated this question in a group of 72 neurologically healthy participants. This is a larger sample than in most previous studies on the topic. Healthy volunteers received tDCS targeting language-related brain regions (Broca’s area in the left hemisphere and/or the homological area in the right hemisphere). Stimulation was followed by two language tests: lexical decision and self-paced sentence reading with comprehension questions. The study found no effect of tDCS on language performance: possibly, due to ceiling effects (initially high performance on the task) or to suboptimal stimulation parameters. However, this does not imply that tDCS will not be effective in supporting language therapy in patients with aphasia. Currently, we are investigating this research question directly in this clinical group.

Project members

Svetlana Malyutina, Valeriya Zelenkova, Olga Buivolova, Elise J. Oosterhuis, Nikita Zmanovsky, Matteo Feurra.

Presentations

Zelenkova V., Buivolova O., Zmanovsky J., Oosterhuis E. J., Feurra M., Malyutina S. Targeting interhemispheric balance to modulate language processing: A tDCS study in a healthy control group. Poster presented at the European Workshop on Cognitive Neuropsychology, Bressanone, Italy, 22-26 January 2018.

Buivolova O. Modulating language processing with tDCS targeting interhemispheric balance. Poster presented at the Neurobiology of Speech and Language workshop, St. Petersburg, 27-29 October 2017.

Publications

Malyutina S., Zelenkova V., Buivolova O., Oosterhuis E. J., Zmanovsky N., Feurra M. Modulating the interhemispheric balance in healthy participants with transcranial direct current stimulation: No significant effects on word or sentence processing // Brain and Language. 2018. Vol. 186. P. 60-66.