Effect of Laryngopharyngeal Neuromuscular Electrical Stimulation on Dysphonia Accompanied by Dysphagia in Post-stroke and Traumatic Brain Injury Patients: A Pilot Study

OBJECTIVE: To investigate the effect of laryngopharyngeal neuromuscular electrical stimulation (NMES) on dysphonia in patients with dysphagia caused by stroke or traumatic brain injury (TBI). METHODS: Eighteen patients participated in this study. The subjects were divided into NMES (n=12) and conventional swallowing training only (CST, n=6) groups. The NMES group received NMES combined with CST for 2 weeks, followed by CST without NMES for the next 2 weeks. The CST group received only CST for 4 weeks. All of the patients were evaluated before and at 2 and 4 weeks into the study. The outcome measurements included perceptual, acoustic and aerodynamic analyses. The correlation between dysphonia and swallowing function was also investigated. RESULTS: There were significant differences in the GRBAS (grade, roughness, breathiness, asthenia and strain scale) total score and sound pressure level (SPL) between the two groups over time. The NMES relative to the CST group showed significant improvements in total GRBAS score and SPL at 2 weeks, though no inter-group differences were evident at 4 weeks. The improvement of the total GRBAS scores at 2 weeks was positively correlated with the improved pharyngeal phase scores on the functional dysphagia scale at 2 weeks. CONCLUSION: The results demonstrate that laryngopharyngeal NMES in post-stroke or TBI patients with dysphonia can have promising effects on phonation. Therefore, laryngopharyngeal NMES may be considered as an additional treatment option for dysphonia accompanied by dysphagia after stroke or TBI.

Ideal Carrier Waveform for Functional Electrical Stimulation in Upper Extremity

OBJECTIVE: This study was purposed to find the ideal carrier waveform in burst wave in Functional Electrical Stimulation (FES) for upper limbs after selection of proper site of electrode. METHOD: The 10 healthy men's non-dominant hands were studied. In 5 muscles (adductor pollicis, flexor digitorum sublimis, flexor pollicis longus, extensor digitorum communis and extensor pollicis brevis), the site where electric stimulus induced the best of purposed response was selected. A burst wave contains three carrier waveforms : sine, triphasic & rectangular. The amount of mean current was measured during key grip and open motion. Discomfort of subject was scored by three degree and compared among three waveforms. RESULTS: The amount of mean current in key grip and open motion is lowest at triphasic wave (31.3 mA, 50.5 mA) and highest at rectangular wave (79.4 mA, 82.1 mA). For the discomfort, rectangular waveform provoke the greatest discomfort in key grip and open motion. There is no statistical difference between sine and triphasic waveform. CONCLUSION: In FES of upper limbs, triangular wave can be an useful carrier waveform which require less amount of current for performing the same motion and less discomfort than rectangular or sine waveform.