The Modulation of Cognitive Performance with Transcranial Alternating Current Stimulation: A Systematic Review of Frequency-Specific Effects

Author: Katharina Klink1,2, Sven Paßmann3, Florian H Kasten4, Jessica Peter2
1 Graduate School for Health Sciences, University of Bern, 3000 Bern, Switzerland.
2 University Hospital of Old Age Psychiatry and Psychotherapy, University of Bern, 3000 Bern, Switzerland.
3 Division of Cognitive Biopsychology and Methods, Department of Psychology, University of Fribourg, 1700 Fribourg, Switzerland.
4 Experimental Psychology Lab., Department of Psychology, European Medical School, Cluster for Excellence "Hearing for All", Carl von Ossietzky University, 26129 Oldenburg, Germany.
Conference/Journal: Brain Sci
Date published: 2020 Dec 2
Other: Volume ID: 10 , Issue ID: 12 , Pages: E932 , Special Notes: doi: 10.3390/brainsci10120932. , Word Count: 189

Transcranial alternating current stimulation (tACS) is a non-invasive brain stimulation technique that allows the manipulation of intrinsic brain oscillations. Numerous studies have applied tACS in the laboratory to enhance cognitive performance. With this systematic review, we aim to provide an overview of frequency-specific tACS effects on a range of cognitive functions in healthy adults. This may help to transfer stimulation protocols to real-world applications. We conducted a systematic literature search on PubMed and Cochrane databases and considered tACS studies in healthy adults (age > 18 years) that focused on cognitive performance. The search yielded n = 109 studies, of which n = 57 met the inclusion criteria. The results indicate that theta-tACS was beneficial for several cognitive functions, including working memory, executive functions, and declarative memory. Gamma-tACS enhanced performance in both auditory and visual perception but it did not change performance in tasks of executive functions. For attention, the results were less consistent but point to an improvement in performance with alpha- or gamma-tACS. We discuss these findings and point to important considerations that would precede a transfer to real-world applications.

Keywords: cognitive performance; systematic review; tACS; transcranial alternating current stimulation.

PMID: 33276533 DOI: 10.3390/brainsci10120932