The goal of this clinical trial is to learn whether individualized transcranial temporal interference stimulation can improve swallowing in adults with swallowing difficulties after an ischemic stroke. It will also evaluate the safety and tolerability of this stimulation. The main questions it aims to answer are: * Does active temporal interference stimulation combined with swallowing rehabilitation improve swallowing safety more than sham stimulation combined with the same rehabilitation? * What side effects or medical problems occur during and after the stimulation? Researchers will compare active stimulation with sham stimulation, which uses the same equipment but does not deliver sustained therapeutic stimulation. Participants will: * Receive active or sham stimulation for 30 minutes per session, 5 days per week for 2 weeks * Receive the same task-specific swallowing rehabilitation after each stimulation session * Undergo swallowing assessments, brain imaging, and neurophysiological testing * Attend follow-up assessments 4 and 12 weeks after treatment
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.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
TRIPLE
Enrollment
88
Individualized active stimulation will be delivered using the NervioX-1000 temporal interference stimulation system. The cerebellar dentate nucleus contralateral to the cerebral lesion will be targeted using an electrode montage and current ratio optimized from individual structural magnetic resonance imaging and finite-element electric-field modelling. Carrier frequencies of 2000 and 2020 Hz will generate a 20-Hz envelope. The maximum peak-to-baseline current will be 2.0 mA. Each session will last 30 minutes, including 30-second ramp-up and ramp-down periods. Treatment will be delivered on 10 weekdays over 2 consecutive weeks.
Sham stimulation will be delivered using the same device, individualized electrode montage, positioning procedures, and session schedule as active stimulation. The device will reproduce the initial ramp-up and brief stimulation sensations and will then ramp down without delivering sustained active stimulation. A brief terminal ramp will reproduce end-of-session sensations. Each sham session will last 30 minutes, and 10 sessions will be administered over 2 consecutive weeks.
Both groups will receive 30 minutes of standardized task-specific swallowing rehabilitation immediately after each active or sham stimulation session. Treatment will be selected according to each participant's swallowing impairment and may include effortful swallowing, the Mendelsohn maneuver, tongue-resistance exercise, chin-tuck-against-resistance exercise, sensory stimulation, and task-specific swallowing practice using clinically appropriate bolus volumes and consistencies.
The First Affiliated Hospital, Zhejiang University School of Medicine
Hangzhou, Zhejiang, China
Change in Penetration-Aspiration Scale Score
The Penetration-Aspiration Scale (PAS) will be scored from videofluoroscopic swallowing study recordings using standardized boluses. Scores range from 1 to 8, with higher scores indicating greater airway invasion and worse swallowing safety. The worst PAS score across the prespecified bolus trials will be used. The primary outcome is the change in PAS score from baseline to immediately after the 2-week intervention.
Time frame: Baseline and immediately after the 2-week intervention
Change in Dynamic Imaging Grade of Swallowing Toxicity
The Dynamic Imaging Grade of Swallowing Toxicity (DIGEST) will be derived from videofluoroscopic swallowing studies. The overall grade ranges from 0 to 4, with higher grades indicating more severe swallowing impairment. Safety and efficiency grades will also be recorded.
Time frame: Baseline, immediately after the 2-week intervention, and at 4- and 12-week follow-up
Change in Functional Oral Intake Scale Score
The Functional Oral Intake Scale (FOIS) evaluates the level of oral food and liquid intake. Scores range from 1 to 7, with higher scores indicating greater oral intake and less dependence on tube feeding or dietary modification.
Time frame: Baseline, immediately after the 2-week intervention, and at 4- and 12-week follow-up
Change in Standardized Swallowing Assessment Score
The Standardized Swallowing Assessment will be used to evaluate clinical signs of swallowing impairment. Higher scores indicate more severe dysphagia.
Time frame: Baseline, immediately after the 2-week intervention, and at 4- and 12-week follow-up
Change in Swallowing Quality of Life Questionnaire Score
The Swallowing Quality of Life Questionnaire (SWAL-QOL) will assess the participant-reported effects of dysphagia on daily life. Scores are transformed to a 0-to-100 scale, with higher scores indicating better swallowing-related quality of life.
Time frame: Baseline, immediately after the 2-week intervention, and at 4- and 12-week follow-up
Change in Maximum Hyoid Displacement
Maximum hyoid displacement will be measured in millimeters from videofluoroscopic swallowing recordings using anatomical calibration. Greater displacement generally indicates better hyolaryngeal excursion.
Time frame: Baseline and immediately after the 2-week intervention
Change in Pharyngeal Transit Time
Pharyngeal transit time will be measured in seconds from videofluoroscopic swallowing recordings. A shorter duration generally indicates more efficient pharyngeal bolus transport.
Time frame: Baseline and immediately after the 2-week intervention
Incidence of Aspiration Pneumonia
The number and proportion of participants who develop clinically adjudicated aspiration pneumonia will be recorded. Diagnosis will be based on prespecified clinical and radiological criteria by assessors unaware of treatment allocation.
Time frame: From randomization through the 12-week follow-up
Incidence of Adverse Events
The number and proportion of participants experiencing adverse events and serious adverse events will be recorded. Events of interest include headache, dizziness, nausea, fatigue, scalp discomfort, skin reactions, neurological deterioration, seizures, falls, hospitalization, and other medical events. Severity and relationship to the intervention will be assessed.
Time frame: During the 2-week intervention and through the 12-week follow-up
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