An interventional study of Conventional Swallowing Therapy and Vitalstim-Sensory NMES in Dysphagia, Stroke and Hemiparesis, sponsored by Istanbul Arel University. Enrolling by invitation at 1 site in Turkey (Türkiye). Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2026-03-03.
Sponsored by Istanbul Arel University · Not applicable, Interventional, and Treatment
This randomized controlled trial aims to investigate the effects of sensory, motor, and modified combined neuromuscular electrical stimulation (NMES) protocols on swallowing function in patients with acute stroke-related dysphagia. The study compares traditional swallowing rehabilitation alone with three NMES-assisted intervention protocols to determine their impact on swallowing safety, efficiency, and rehabilitation outcomes. Ultrasonographic assessment of hyoid-laryngeal motion will be used as the primary instrumental outcome.
This randomized controlled, double-blind clinical trial aims to investigate the effects of different neuromuscular electrical stimulation (NMES) protocols-sensory, motor, and modified combined-on the swallowing function and suprahyoid muscle morphology in patients with acute hemiparetic stroke. Dysphagia is one of the most common and serious complications following stroke, leading to nutritional deficiencies, aspiration risk, and reduced quality of life. NMES has been increasingly used in dysphagia rehabilitation as a noninvasive technique that facilitates both peripheral muscle activation and central neuroplasticity.
A total of 40 acute hemiparetic stroke patients diagnosed with dysphagia will be recruited from the Acute Stroke Center of Istinye University Liv Hospital and randomly assigned to four groups:
Group 1: Sensory stimulation (submotor level, below contraction threshold) Group 2: Motor stimulation (supramotor level, visible contraction) Group 3: Modified combined stimulation (motor stimulation on the paretic side and sensory stimulation on the contralateral side) Group 4: Control group (conventional swallowing rehabilitation only) All intervention groups will receive NMES in addition to conventional dysphagia therapy for 10 sessions (40 minutes each). NMES parameters will be standardized as follows: channel mode co-contraction, frequency 80 Hz, pulse duration 180 μs, on-time 3 seconds, and off-time 20 seconds. Electrodes will be placed bilaterally, with the upper pair located above the hyoid bone and the lower pair over the thyrohyoid muscle.
The primary outcome measures will include ultrasonographic assessment of the suprahyoid muscles (muscle thickness, cross-sectional area, echo intensity, and shear-wave elasticity) and dynamic analysis of hyoid-laryngeal movement during swallowing of 5 mL boluses with standardized viscosity levels (IDDSI Level 0 and 4). Measurements will be performed using a LOGIQ P8 ultrasound system with B- and M-mode imaging according to Matsuo's hyoid-laryngeal motion index method.
The secondary outcome measures include videofluoroscopic swallowing study (VFSS) parameters such as the Penetration-Aspiration Scale (PAS), Bolus Residue Scale (BRS), and DIGEST scale, as well as clinical assessments like the Functional Oral Intake Scale (FOIS) and a Nurse Evaluation Form assessing perceived functional improvement via a visual analog scale.
Randomization will be computer-generated (randomizer.org), and all outcome assessments will be conducted by blinded evaluators. The intervention will be delivered by an experienced physiotherapist specialized in dysphagia management.
This study aims to provide comparative evidence on how different NMES stimulation types influence swallowing safety, efficiency, and muscle adaptation in acute stroke. By integrating instrumental (ultrasound and VFSS) and clinical outcomes, the findings will help identify the most effective NMES protocol and contribute to the development of individualized, evidence-based rehabilitation approaches for neurogenic dysphagia.
Exclusion Criteria:
Participants receive sensory-level neuromuscular electrical stimulation (NMES) applied to the suprahyoid muscles using a therapeutic stimulator. The stimulation is delivered at sensory threshold without visible muscle contraction. Sessions last approximately 30 minutes for a total of 10 sessions. In addition, participants receive conventional swallowing therapy, including traditional swallowing exercises and compensatory strategies.
Device: Vitalstim-Sensory NMES
Participants receive motor-level neuromuscular electrical stimulation (NMES) applied to the suprahyoid muscles using a therapeutic stimulator. The stimulation is delivered at motor threshold with visible muscle contraction. Sessions last approximately 30 minutes for a total of 10 sessions. In addition, participants receive conventional swallowing therapy, including traditional swallowing exercises and compensatory strategies.
Device: Vitalstim-Motor NMES
Participants receive combined neuromuscular electrical stimulation (NMES) applied to the suprahyoid muscles using a therapeutic stimulator. Motor-level NMES is applied to the hemiparetic side at motor threshold with visible muscle contraction, while sensory-level NMES is applied simultaneously to the contralateral (non-hemiparetic) side at sensory threshold without visible muscle contraction. Sessions last approximately 30 minutes for a total of 10 sessions. In addition, participants receive conventional swallowing therapy, including traditional swallowing exercises and compensatory strategies.
Device: Vitalstim-Combine NMES
Participants receive conventional swallowing therapy without neuromuscular electrical stimulation (NMES). Conventional therapy includes traditional swallowing exercises and compensatory strategies administered by a therapist, such as effortful swallow, Mendelsohn maneuver, and tongue base exercises. Sessions last approximately 30 minutes for a total of 10 sessions.
Behavioral: Conventional Swallowing Therapy
Participants receive only conventional swallowing therapy without neuromuscular electrical stimulation (NMES). Conventional swallowing therapy consists of structured swallowing exercises and compensatory strategies administered by a therapist, including effortful swallow, Mendelsohn maneuver, tongue base exercises, and postural adjustments as clinically indicated. Sessions last approximately 30 minutes for a total of 10 sessions.
Participants receive sensory-level neuromuscular electrical stimulation (NMES) applied to the suprahyoid muscles using a therapeutic stimulator. Stimulation is delivered at sensory threshold without visible muscle contraction. Sessions last approximately 30 minutes for a total of 10 sessions. In addition, participants receive conventional swallowing therapy consisting of structured swallowing exercises and compensatory strategies, including effortful swallow, Mendelsohn maneuver, tongue base exercises, and postural adjustments as clinically indicated.
Participants receive motor-level neuromuscular electrical stimulation (NMES) applied to the suprahyoid muscles using a therapeutic stimulator, eliciting visible muscle contraction. Sessions last approximately 30 minutes for a total of 10 sessions. In addition, participants receive conventional swallowing therapy consisting of structured swallowing exercises and compensatory strategies, including effortful swallow, Mendelsohn maneuver, tongue base exercises, and postural adjustments as clinically indicated.
Participants receive combined neuromuscular electrical stimulation (NMES) applied to the suprahyoid muscles using a therapeutic stimulator. Motor-level NMES is applied to the hemiparetic side, while sensory-level NMES is applied to the contralateral side within the same session. Sessions last approximately 30 minutes for a total of 10 sessions. In addition, participants receive conventional swallowing therapy consisting of structured swallowing exercises and compensatory strategies, including effortful swallow, Mendelsohn maneuver, tongue base exercises, and postural adjustments as clinically indicated.
Change in Suprahyoid Muscle Thickness
Suprahyoid muscle thickness will be quantitatively measured using B-mode ultrasonography (LOGIQ P8, GE Healthcare). Measurements will be obtained at standardized anatomical landmarks by a trained examiner while participants are in a supine position with the head in neutral alignment. Thickness values will be recorded in millimeters and averaged over repeated measurements to assess morphological changes following the intervention.
Time frame: Baseline (Day 0) and End of treatment (after 10 sessions, Week 2)
Change in Suprahyoid Muscle Cross-Sectional Area
The cross-sectional area of the suprahyoid muscle group will be assessed using B-mode ultrasonography. Images will be captured in the transverse plane, and cross-sectional area will be calculated using image analysis software. This outcome reflects structural adaptations of the swallowing-related musculature in response to different NMES protocols.
Time frame: Baseline (Day 0) and End of treatment (after 10 sessions, Week 2)
Change in Suprahyoid Muscle Echogenicity
Muscle echogenicity will be evaluated through grayscale analysis of B-mode ultrasound images. Mean grayscale values will be calculated to reflect muscle quality, with higher echogenicity indicating increased intramuscular connective or fatty tissue. Changes in echogenicity will be used as an indicator of muscle composition and structural integrity.
Time frame: Baseline (Day 0) and End of treatment (after 10 sessions, Week 2)
Change in Suprahyoid Muscle Stiffness
Muscle stiffness will be assessed using shear wave elastography (SWE). Quantitative stiffness values (expressed in kilopascals) will be obtained from the suprahyoid muscle region during rest. SWE measurements provide information on the mechanical properties of muscle tissue and potential neuromuscular adaptations following NMES.
Time frame: Baseline (Day 0) and End of treatment (after 10 sessions, Week 2)
Change in Penetration-Aspiration Scale (PAS) Score
Swallowing safety will be evaluated using Videofluoroscopic Swallowing Study (VFSS) performed by an experienced clinician according to standardized protocols. Participants will swallow standardized bolus volumes and consistencies based on the International Dysphagia Diet Standardisation Initiative (IDDSI) framework. VFSS recordings will be analyzed frame-by-frame, and airway invasion severity will be rated using the Penetration-Aspiration Scale (PAS), which ranges from 1 (no airway entry) to 8 (silent aspiration). PAS scores will be used to quantify changes in airway protection following the intervention.
Time frame: Baseline (Day 0) and End of treatment (after 10 sessions, Week 2)
Change in Bolus Residue Scale (BRS) Score
Pharyngeal residue severity will be assessed during VFSS using the Bolus Residue Scale (BRS). VFSS examinations will include multiple swallows of standardized boluses across different IDDSI consistencies. Post-swallow residue will be evaluated in predefined anatomical regions and scored according to the BRS criteria to quantify bolus clearance efficiency and residue severity.
Time frame: Baseline (Day 0) and End of treatment (after 10 sessions, Week 2)
Change in Dynamic Imaging Grade of Swallowing Toxicity (DIGEST) Score
Overall swallowing function will be assessed using the Dynamic Imaging Grade of Swallowing Toxicity (DIGEST) during VFSS. DIGEST scoring integrates VFSS-derived measures of airway invasion (PAS) and pharyngeal residue severity to provide a global classification of swallowing safety and efficiency. VFSS recordings will be reviewed by trained raters using standardized criteria.
Time frame: Baseline (Day 0) and End of treatment (after 10 sessions, Week 2)
Changes in Functional Oral Intake Scale (FOIS)
Functional Oral Intake Scale (FOIS) will be used to evaluate changes in patients' functional oral intake level and dietary restrictions. The FOIS is a 7-point ordinal scale ranging from 1 (nothing by mouth) to 7 (total oral diet with no restrictions). The scale reflects the patient's ability to safely consume food and liquids orally in daily life. FOIS scores will be determined based on clinical evaluation, dietary intake records, and multidisciplinary team assessment, reflecting functional swallowing performance outside the instrumental assessment setting.
Time frame: Baseline (Day 0) and End of treatment (after 10 sessions, Week 2)
Changes in Nurse Observation Form for Swallowing Function
Swallowing-related functional changes will be assessed using a Nurse Observation Form completed by trained nursing staff during routine meals. The form evaluates observable swallowing-related behaviors and signs, including oral control, coughing or choking episodes, voice quality changes after swallowing, secretion management, and overall feeding tolerance. The Nurse Observation Form provides real-world, bedside information on swallowing safety and functional performance during daily oral intake.
Time frame: Baseline (Day 0) and End of treatment (after 10 sessions, Week 2)
Plan to share: No — De-identified individual participant data (IPD) may be shared with qualified researchers upon reasonable request and approval from the principal investigator and relevant ethics committee.
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Istanbul Arel University