Investigation of the Effect of Neuromuscular Electrical Stimulation Techniques on Suprahyoid Muscles and Swallowing Function in Acute Hemiparetic Stroke Patients

Condition(s) studied

Investigational drug(s) / intervention(s)

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.

Vitalstim-Sensory NMES: 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.

Vitalstim-Motor NMES: 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.

Vitalstim-Combine 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, 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.

Study summary

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.

Eligibility

Primary outcome measure(s)

• Change in Suprahyoid Muscle Thickness — Baseline (Day 0) and End of treatment (after 10 sessions, Week 2)
  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.
• Change in Suprahyoid Muscle Cross-Sectional Area — Baseline (Day 0) and End of treatment (after 10 sessions, Week 2)
  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.
• Change in Suprahyoid Muscle Echogenicity — Baseline (Day 0) and End of treatment (after 10 sessions, Week 2)
  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.
• Change in Suprahyoid Muscle Stiffness — Baseline (Day 0) and End of treatment (after 10 sessions, Week 2)
  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.
• Change in Penetration-Aspiration Scale (PAS) Score — Baseline (Day 0) and End of treatment (after 10 sessions, Week 2)
  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.
• Change in Bolus Residue Scale (BRS) Score — Baseline (Day 0) and End of treatment (after 10 sessions, Week 2)
  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.
• Change in Dynamic Imaging Grade of Swallowing Toxicity (DIGEST) Score — Baseline (Day 0) and End of treatment (after 10 sessions, Week 2)
  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.

Trial sites (1)

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