Journal article
Addressing transcranial electrical stimulation variability through prospective individualized dosing of electric field strength in 300 participants across two samples: the 2-SPED approach
Hasselt University1
Medical University of South Carolina2
Leibniz Research Centre for Working Environment and Human Factors3
Neurophysics, Magnetic Resonance, Department of Health Technology, Technical University of Denmark4
Magnetic Resonance, Department of Health Technology, Technical University of Denmark5
Department of Health Technology, Technical University of Denmark6
Objective. Transcranial electrical stimulation (tES) is a promising method for modulating brain activity and excitability with variable results to date. To minimize electric (E-)field strength variability, we introduce the 2-sample prospective E-field dosing (2-SPED) approach, which uses E-field strengths induced by tES in a first population to individualize stimulation intensity in a second population.
Approach. We performed E-field modeling of three common tES montages in 300 healthy younger adults. First, permutation analyses identified the sample size required to obtain a stable group average E-field in the primary motor cortex (M1), with stability being defined as the number of participants where all group-average E-field strengths ± standard deviation did not leave the population’s 5-95 percentile range.
Second, this stable group average was used to individualize tES intensity in a second independent population (n = 100). The impact of individualized versus fixed intensity tES on E-field strength variability was analyzed. Main results. In the first population, stable group average E-field strengths (V/m) in M1 were achieved at 74-85 participants, depending on the tES montage.
Individualizing the stimulation intensity (mA) in the second population resulted in uniform M1 E-field strength (all p < 0.001) and significantly diminished peak cortical E-field strength variability (all p < 0.01), across all montages. Significance. 2-SPED is a feasible way to prospectively induce more uniform E-field strengths in a region of interest.
Future studies might apply 2-SPED to investigate whether decreased E-field strength variability also results in decreased physiological and behavioral variability in response to tES.
Language: | English |
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Publisher: | IOP Publishing |
Year: | 2022 |
ISSN: | 17412552 and 17412560 |
Types: | Journal article |
DOI: | 10.1088/1741-2552/ac9a78 |
ORCIDs: | 0000-0002-0325-8950 , 0000-0001-8268-4204 , Thielscher, Axel and 0000-0002-7938-3758 |