BILATERAL tDCS-DYSPHAGIA
(2026)Objective
To determine whether bilateral anodal transcranial direct current stimulation (tDCS) combined with intensive speech-language therapy (SLT) improves swallowing outcomes compared with sham stimulation in patients with post-stroke oropharyngeal dysphagia.
Study Summary
• No significant between-group difference on the primary DOSS endpoint (delta 2 weeks or 6 weeks; all p>0.05)
• Exploratory analysis: active tDCS produced significantly larger MASA gains than sham in infratentorial strokes at 2 weeks (p=0.04)
• Stimulation was well tolerated with no adverse events reported in either arm
Intervention
Bilateral anodal tDCS (1.5 mA, 20 min/day, 5 days/week for 2 weeks; two 5x7 cm anodes over the orofacial swallowing cortices bilaterally with contralateral cathodes) delivered concurrently with 6 weeks of intensive 40-min daily SLT, versus sham tDCS + identical intensive SLT.
Inclusion Criteria
Adults >=18 years with first-ever or recurrent supratentorial or infratentorial ischemic stroke confirmed on neuroimaging; FEES-confirmed oropharyngeal dysphagia (DOSS <=6); stroke onset 72 hours to 6 months; able to participate in SLT; informed consent.
Study Design
Arms: Bilateral anodal tDCS + intensive SLT vs Sham tDCS + intensive SLT (1:1 randomization, double-blind, centralized).
Patients per Arm: 24 active bilateral anodal tDCS (24 completed); 24 sham tDCS (22 completed; 2 discontinued for logistic reasons). Total analyzed: 46.
Outcome
• PAS improved in both arms at 6 weeks (anodal 3.4->2.6; sham 3.8->2.9); MASA improved in both (anodal 158->176; sham 154->169); SWAL-QoL improved in both (anodal 142->176; sham 148->183)
• Infratentorial subgroup: active tDCS produced significantly greater MASA gains than sham at 2 weeks (p=0.04); trend for DOSS at 2 weeks (p=0.07)
• Greater baseline dysphagia severity predicted larger functional gains across measures
• No adverse events; blinding qualitatively maintained
Clinical Question
In patients with subacute to early chronic post-stroke oropharyngeal dysphagia (72 h to 6 months post-stroke), does bilateral anodal tDCS over the swallowing cortices, combined with 6 weeks of intensive speech-language therapy, improve swallowing function more than sham tDCS plus the same intensive SLT?
Bottom Line
Six weeks of intensive speech-language therapy produced significant, clinically meaningful improvements in swallowing across DOSS, PAS, MASA and SWAL-QoL in both arms, with no overall superiority of bilateral anodal tDCS over sham; exploratory analyses suggest a possible additional benefit in infratentorial strokes.
Major Points
- Multicenter (5 Italian centers), randomized, double-blind, sham-controlled trial (NCT07152899) enrolling 48 patients (46 completed) with supra- or infratentorial ischemic post-stroke oropharyngeal dysphagia (72 h - 6 months post-onset).
- Bilateral anodal tDCS (1.5 mA x 20 min, 5 days/week for 2 weeks; two 5x7 cm anodes over orofacial swallowing cortices, contralateral 10x10 cm cathodes) was combined with 6 weeks of intensive 40-min/day SLT.
- Primary DOSS outcome improved significantly within both arms at 2 and 6 weeks (all p<0.001), with no significant between-group difference in delta DOSS.
- Secondary outcomes (PAS, MASA, SWAL-QoL) also improved in both arms without between-group differences overall.
- Exploratory: in infratentorial strokes, active tDCS produced significantly greater MASA gains than sham at 2 weeks (p=0.04); higher baseline severity (lower MASA, higher PAS, higher NIHSS) predicted larger gains.
- Stimulation was well tolerated with no adverse events; qualitative blinding was maintained.
- Authors interpret findings as evidence that intensive prolonged SLT is the main driver of recovery, with tDCS possibly adding benefit only in selected lesion subgroups (infratentorial).
Study Design
- Study Type
- Randomized Controlled Trial
- Randomization
- Yes
- Blinding
- Double-blind (patients and outcome assessors blinded; centralized 1:1 randomization)
- Sample Size
- 48
- Follow-up
- 6 weeks (assessments at baseline, 2 weeks/end of stimulation, 6 weeks/end of SLT)
- Centers
- 5
- Countries
- Italy
Primary Outcome
Definition: Improvement in swallowing function assessed by the Dysphagia Outcome and Severity Scale (DOSS) at 2 weeks (end of stimulation) and 6 weeks (end of intensive SLT).
| Control | Intervention | HR/OR | P-value |
|---|---|---|---|
| - | - | - | Within-group p<0.001 in both arms; between-group NS |
Limitations & Criticisms
- Small sample size (46 completed) limits power to detect modest between-group differences and precludes formal stratified subgroup inference, particularly for the infratentorial signal.
- Broad recruitment window (72 h - 6 months post-stroke) introduces heterogeneity in spontaneous recovery trajectories that may mask a true tDCS effect.
- Very intensive SLT program (40 min/day, 5 days/week, 6 weeks) may have produced a ceiling effect leaving little margin for additional neuromodulatory benefit.
- Inclusion of patients with only mild-to-moderate dysphagia further reduces the detectable margin of improvement.
- Bilateral montage using standardized scalp coordinates may generate diffuse cortical fields and lacks individualized neuronavigation or TMS-guided targeting.
- Delayed ClinicalTrials.gov registration (NCT07152899) due to COVID-19 pandemic constraints (registered retrospectively).
- No untreated control arm (ethically precluded), so absolute contribution of spontaneous recovery vs SLT cannot be isolated.
- Blinding success was assessed only qualitatively, not with a formal instrument.
- Single-country (Italian) recruitment limits generalizability; only ischemic strokes included.
- Exploratory subgroup analyses (including the positive infratentorial MASA finding) are hypothesis-generating and not adjusted for multiple comparisons across subgroups.
Citation
Eur J Neurol 2026;33:e70686