# Residual effect of sequential 4-channel neuromuscular electrical stimulation evaluated by high-resolution manometry

## TL;DR

This study shows that a new type of electrical stimulation during swallowing can improve throat muscle function, with possible lasting effects.

## Contribution

The study introduces sequential 4-channel NMES and evaluates its residual effects on swallowing physiology using HRM.

## Key findings

- Sequential 4-channel NMES significantly improved HRM parameters like pressure and area in the velopharynx and mesopharynx.
- Improvements in pressure and area variables showed a tendency to persist after NMES, though not statistically significant.
- NMES application on suprahyoid and infrahyoid muscles during swallowing enhances oropharyngeal function as measured by HRM.

## Abstract

High-resolution manometry (HRM) can quantify swallowing pathophysiology to evaluate the status of the pharynx. Sequential 4-channel neuromuscular electrical stimulation (NMES) was recently developed based on the normal contractile sequences of swallowing-related muscles. This study aimed to examine the effects of sequential 4-channel NMES for compensatory application during swallowing and to observe the residual effects after the application of NMES using HRM.

Sequential 4-channel NMES significantly improved the HRM parameters, with respect to the maximal pressure and area of the velopharynx (VP), maximal pressure and area of the mesopharynx (MP), and upper esophageal sphincter (UES) activation and nadir duration. Furthermore, the improvement in the pressure and area variables of the VP and MP showed a tendency to maintain even when measured after NMES, but there are no significant differences.

The present study suggests that the sequential 4-channel NMES application of the suprahyoid and infrahyoid muscles during swallowing improves the pressure, area, and time variables of the oropharynx, as measured by HRM, and it is likely that the effects may persist even after stimulation.

Trial Registration Clinicaltrials.gov, registration number: NCT02718963 (initial release: 03/20/2016, actual study completion date: 06/24/2016, last release: 10/20/2020).