Investigation of the Effect of Neuromuscular Electrical Stimulation Techniques on Suprahyoid Muscles and Swallowing Function in Acute Hemiparetic Stroke Patients
Overview
- Phase
- Not Applicable
- Status
- Enrolling By Invitation
- Sponsor
- Istanbul Arel University
- Enrollment
- 40
- Locations
- 1
- Primary Endpoint
- Change in Suprahyoid Muscle Thickness
Overview
Brief 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.
Detailed Description
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.
Study Design
- Study Type
- Interventional
- Allocation
- Randomized
- Intervention Model
- Parallel
- Primary Purpose
- Treatment
- Masking
- Double (Participant, Outcomes Assessor)
Masking Description
The study is double-blind. Both participants and outcome assessors are blinded to group allocation. Participants are unaware of whether they receive sensory, motor, combined NMES, or control intervention, as all sessions are conducted using identical equipment and electrode placement. Outcome assessors who analyze VFSS data are also blinded to the intervention groups.
Eligibility Criteria
- Ages
- 18 Years to — (Adult, Older Adult)
- Sex
- All
- Accepts Healthy Volunteers
- No
Inclusion Criteria
- •Age ≥ 18 years, Diagnosis of unilateral hemispheric stroke (ischemic or hemorrhagic) within the past month, Modified Rankin Scale score ≤ 2, NIH Stroke Scale (NIHSS) score ≤ 25, Gugging Swallowing Screen (GUSS) score \< 20, Ability to maintain upright sitting position during VFSS and therapy sessions, Voluntary participation with signed informed consent
Exclusion Criteria
- •History of secondary stroke, Inability to follow simple verbal commands Unstable medical condition, History of head or neck cancer, neoplastic tissue growth, or epileptic seizures, Presence of musculoskeletal disorders affecting the neck or swallowing muscles, Cognitive impairment indicated by an IQCODE score \> 3.4, Any neurological disease other than stroke that may cause swallowing disorders
Arms & Interventions
Sensory NMES Group
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.
Intervention: Vitalstim-Sensory NMES (Device)
Motor NMES Group
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.
Intervention: Vitalstim-Motor NMES (Device)
Combined NMES Group
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.
Intervention: Vitalstim-Combine NMES (Device)
Control Group
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.
Intervention: Conventional Swallowing Therapy (Behavioral)
Outcomes
Primary Outcomes
Change in Suprahyoid Muscle Thickness
Time Frame: 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
Time Frame: 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
Time Frame: 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
Time Frame: 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
Time Frame: 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
Time Frame: 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
Time Frame: 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.
Secondary Outcomes
- Changes in Functional Oral Intake Scale (FOIS)(Baseline (Day 0) and End of treatment (after 10 sessions, Week 2))
- Changes in Nurse Observation Form for Swallowing Function(Baseline (Day 0) and End of treatment (after 10 sessions, Week 2))
Investigators
Rabia KUM GULER
Lecturer
Istanbul Arel University