Study extension (amendment to protocol UCV/2021-2022/140, approved by the Research Ethics Committee of the Catholic University of Valencia, ref. UCV/2022-2023/072, on October 28, 2024). After the initial phase, in which participants with Long COVID received anodal tDCS, the study was extended to a randomized, sham-controlled, double-blind phase. Participants are randomized 1:1:1:1 to anodal (original arm, recruitment continued), bifrontal, cathodal or sham tDCS. Objectives, eligibility criteria and primary outcome are unchanged. Planned enrollment: initial phase, 27 participants; randomized extension phase, 60 participants (15 per arm). Between-group comparisons will include only participants randomized in the extension phase; initial-phase data will be reported separately and used only in supplementary analyses within the anodal tDCS arm. Sleep outcomes (PSQI, ISI, ESS) were added as secondary outcomes in the extension phase only.
The initial phase was approved by the Research Ethics Committee of the Catholic University of Valencia (ref. UCV/2021/2022/140); the extension was approved by the Research Ethics Committee of the Catholic University of Valencia (ref. UCV/2022-2023/072) on October 28, 2024.
