Modulação cortical e somatossensorial imediata distinta induzida por tACS e tDCS em adultos jovens saudáveis: um ensaio clínico randomizado controlado

Abstract

Transcranial electrical stimulation (tES) techniques—particularly transcranial direct current stimulation (tDCS) and transcranial alternating current stimulation (tACS)—can modulate cortical excitability and oscillatory activity. However, direct comparative data on their immediate neurofunctional effects in healthy humans remain limited. Objective: To compare the acute effects of tACS and tDCS on cortical and somatosensory metrics derived from the Brain Gauge system in healthy young adults. Methods: In this randomized controlled trial, 65 participants (33 tACS, 32 tDCS) received a single 20- min stimulation targeting the left dorsolateral prefrontal cortex (F3–Fp2 montage). The tDCS group received 2 mA direct current, and the tACS group received 1 mA alternating current at 40 Hz. Vibrotactile performance was assessed before and immediately after stimulation using standardized Brain Gauge tests (Focus, Speed, corticalmetric, Reaction Time Variability). Data were analyzed using repeatedmeasures general linear models including demographic and psychometric covariates. Results: Across the full sample, Focus (p = 0.0026, η² = 0.094), Speed (p = 0.046, η² =0.043), and corticalmetric (p = 0.027, η² = 0.052) improved significantly after stimulation. Stratified analyses revealed that that both groups improved Focus and corticalmetric, despite only tACS presented improvements in speed and have effects influenced by educational Level. Conclusions: Single-session tACS at 40 Hz and tDCS can improve attentional control and cortical function, however, only tACS effects can be influenced by education level. These findings highlight that despite tACS and tDCS have potential role in precision neuromodulation, however, level of education must be considered in tACS application.