Surface Electromyographic Analysis of Normal Swallowing in Children: An Exploratory Study

Overview

This exploratory clinical trial aims to investigate the mechanism of sequential muscle contractions during normal swallowing processes, including spoon, straw, and cup feeding, in children aged 2 to under 10 years without swallowing disorders. Surface electromyography (sEMG) will be used to evaluate activation patterns of the orbicularis oris, submental, and hyoid muscles during liquid, semi-solid, and solid intake. The study seeks to characterize the timing, duration, amplitude, and coordination of swallowing-related muscle activity in typically developing children. Findings from this study are expected to provide foundational physiological data to inform the development of pediatric-specific neuromuscular electrical stimulation (NMES) protocols for dysphagia treatment.

Background and Rationale Swallowing is a complex neuromuscular process requiring coordinated and sequential activation of orofacial and suprahyoid muscles. While neuromuscular electrical stimulation (NMES) has been widely applied in adult dysphagia rehabilitation, pediatric-specific physiological data on swallowing muscle activation patterns remain limited. Current clinical practice often extrapolates adult treatment protocols to pediatric populations, despite developmental differences in anatomy, neuromuscular control, and feeding mechanisms. Understanding the normative sequential activation patterns of swallowing-related muscles in children is essential for developing age-appropriate therapeutic protocols. This study aims to establish baseline physiological data on muscle activation sequencing during various feeding methods in typically developing children. Study Design This is an exploratory, single-center clinical study enrolling 30 children aged 2 to under 10 years without diagnosed swallowing disorders. Participants will undergo non-invasive surface electromyography (sEMG) assessments during standardized feeding tasks. Study Procedures 1. Spoon Feeding Mechanism Assessment Participants will consume: 3-5 cc of liquid using a spoon 3-5 cc of yogurt (semi-solid consistency) using a spoon Solid food using a spoon Surface EMG electrodes will be placed over the: Orbicularis oris Submental muscle group Hyoid-related musculature Muscle activation patterns during swallowing will be recorded. 2. Straw Feeding Mechanism Assessment Participants will consume 5-10 cc of liquid using a straw while sEMG signals are recorded from the same muscle groups. 3. Cup Drinking Mechanism Assessment Participants will consume 5-10 cc of liquid from a cup with simultaneous sEMG recording. Data Collection Observational Variables Name Age Birth history (gestational age, birth weight, delivery method) Sex Race Height and weight Medical history Surgical history Medication use History of pneumonia Diagnosis of swallowing disorder Anthropometric Measurements Distance from mandible midpoint to hyoid bone Distance between bilateral angles of the mandible Distance from hyoid bone to clavicle Bilateral neck width at the level of the thyroid cartilage Surface Electromyography (sEMG) Outcome Measures Primary electrophysiological variables include: Onset latency Offset latency Duration of muscle contraction Peak amplitude Area Under the Curve (AUC) The primary outcome measure is the sequential activation pattern of swallowing-related muscles (orbicularis oris, submental, and hyoid muscles). Statistical Analysis Descriptive statistics will be reported as mean ± standard deviation. Normality will be assessed using the Shapiro-Wilk test. Comparisons of non-nutritive versus nutritive swallowing within the same participant will be analyzed using the Wilcoxon signed-rank test. Sequential muscle activation order (e.g., onset timing differences among muscles) will be analyzed using the Friedman test. A p-value \< 0.05 will be considered statistically significant. Expected Significance This study aims to clarify the physiological mechanisms of sequential muscle activation during swallowing in typically developing children. The findings are expected to provide essential normative data for the development of pediatric-specific NMES protocols for dysphagia treatment. Establishing age-appropriate stimulation parameters may ultimately contribute to more effective and developmentally tailored therapeutic interventions in pediatric populations.