Dentate-Targeted Temporal Interference Stimulation for Post-Stroke Dysphagia

Post-stroke dysphagia is associated with aspiration, pneumonia, malnutrition, prolonged hospitalization, functional dependence, and mortality. Although conventional swallowing rehabilitation can improve swallowing function, recovery is often incomplete. Transcranial temporal interference stimulation (tTIS) is an investigational, noninvasive neuromodulation technique that uses intersecting high-frequency electrical currents to generate a lower-frequency stimulation envelope within a selected deep-brain target.

This prospective, single-center, randomized, double-blind, sham-controlled trial will enroll 88 adults with dysphagia following a first unilateral supratentorial ischemic stroke. Participants will be randomly assigned in a 1:1 ratio to receive active or sham tTIS. Both groups will receive identical task-specific swallowing rehabilitation. The stimulation target will be the cerebellar dentate nucleus contralateral to the cerebral lesion. Individual structural magnetic resonance imaging and finite-element electric-field modelling will be used to optimize electrode placement and the current ratio for each participant.

The active intervention will use two carrier frequencies of 2000 and 2020 Hz to generate a 20-Hz envelope. Each stimulation session will last 30 minutes and will be followed by standardized swallowing rehabilitation. Participants will receive 10 weekday sessions over 2 consecutive weeks. The sham group will undergo the same procedures and treatment schedule without sustained active stimulation.

Clinical assessments will be conducted at baseline, immediately after the 2-week intervention, and at 4- and 12-week follow-up. Videofluoroscopic swallowing studies will be used to evaluate swallowing safety and efficiency. Neurophysiological testing and resting-state functional magnetic resonance imaging will be used to explore whether treatment-related swallowing improvement is associated with changes in corticobulbar excitability and functional connectivity within the dentato-thalamo-cortical swallowing network.

Inclusion criteria

• Age 18 to 80 years
• First-ever unilateral supratentorial ischemic stroke confirmed by computed tomography or magnetic resonance imaging
• Stroke onset 14 to 90 days before randomization
• Oropharyngeal dysphagia confirmed by videofluoroscopic swallowing study, with a worst Penetration-Aspiration Scale score of 3 to 7 during prespecified standardized bolus trials
• Medically stable and able to remain seated during stimulation and swallowing rehabilitation
• Able to follow one-step commands, directly or with supported communication
• Written informed consent provided by the participant or a legally authorized representative

Exclusion criteria

• Brainstem or primary cerebellar stroke, bilateral cerebral infarction, previous symptomatic stroke, intracranial hemorrhage, or progressive neurological disease
• Pre-stroke dysphagia, structural oropharyngeal disease, previous treatment for head and neck cancer, or another condition that independently explains dysphagia
• Tracheostomy, current mechanical ventilation, uncontrolled pneumonia, severe hypoxemia, or hemodynamic instability
• History of epilepsy, seizure after the index stroke, unexplained loss of consciousness, or current use of medication considered to confer an unacceptable seizure risk
• Intracranial metallic material, implanted electronic device, cochlear implant, or another contraindication to transcranial temporal interference stimulation, magnetic resonance imaging, or transcranial magnetic stimulation
• Severe cognitive, behavioral, or language impairment that prevents participation despite supported communication
• Pregnancy or breastfeeding
• Major scalp disease at the planned electrode sites
• Participation in another interventional clinical trial
• Any other condition considered unsafe or unsuitable by the investigator