This comprehensive study aimed to evaluate the impact of neuromuscular electrical stimulation (NMES) on laryngeal function, investigating its efficacy in both healthy subjects and cases of unilateral vocal fold paralysis (UVFP). Our objectives were to explore various NMES applications and their influence on laryngeal muscle activity to comprehend their distinct effects.
Our investigation included multiple experiments to gauge the influence of NMES, using laryngeal imaging, acoustic analysis, electroglottography, and accelerometric techniques. We applied the VitalStim device with varying frequencies of stimulation (5 to 80 Hz) and monitored the progress over time.
Our study revealed significant alterations in laryngeal configuration and vocal output in response to NMES. Fundamental frequency increased, and glottal adduction improved, notably with lower frequencies of NMES (i.e., 5 and 10 Hz) penetrating deeper tissue, enhancing glottal closure. Acoustic values significantly improved for UVFP cases when the paralysed vocal fold is found in the paramedian position, whereas those with medially paralyzed vocal folds did not show the same level of improvement.
Our application of NMES induced changes in intrinsic laryngeal muscles, leading to increased muscle activation and adduction within minutes of application. Furthermore, the investigation highlighted that distinct configurations of UVFP respond differently to NMES. The study concluded that NMES exhibited promising outcomes in enhancing vocal parameters. These findings underscored the effectiveness of NMES in voice therapy, underscoring its potential as a valuable and viable treatment for voice disorders.

At the conclusion of my presentation, attendees will gain an appreciation for the following:
1. Biophysical principles of NMES concerning the frequency of stimulation.
2. Advantages of short-term NMES application for alterations in glottal configuration.
3. Variances in NMES application according to UVFP configurations (median vs paramedian positions).