Investigation of Superior Laryngeal Nerve Disorders with Laryngeal Electromyography in Patients with Hoarseness

Abstract

Introduction:In this study, we aimed to investigate the laryngeal electromyography (L-EMG) findings of organic and functional laryngeal pathologies that affect superior laryngeal nerve in patients with hoarseness.Methods:All patients underwent routine examination and videolaryngoscopy using a 70-degree 4-mm telescope. L-EMG studies were performed via portable Dantec™ Keypoint® EMG/ NCS/EP Workstation with 2-channel options. For EMG, 20 mm bipolar concentric needle electrodes were used. Because the procedure was relatively painless and local anesthetics could affect the function of the muscles, no local anesthesia was administered to the patients. Cricothyroid muscle (CTM) and thyroarytenoid muscle (TAM) were tested by electromyography method.Results:Twenty-four patients with hoarseness were included in the study. Eleven patients (46%) were male and 13 (54%) were female. The mean age was 37.62 years (range: 15-57 years). A total of 96 muscles were examined with EMG. L-EMG was pathological in 15 patients (62.5%) and bilateral pathology was observed in three patients. Twenty muscles (20.8%) were detected as pathological, with neurogenic involvement in 20 muscles (70%), poor activity or no activity in four muscles (20%) and dystonic activity in two muscles (10%). Eight right CTMs (five neurogenic involvement, two poor activity, one no activity) and five left CTMs (two neurogenic involvement, one poor activity, two dystonic activity) were pathological. TAMs had neurogenic involvement on the right side in four patients and on the left side in three patients.Conclusion:It should be kept in mind that L-EMG may be an adjunctive application for detecting pathologies with neurogenic or myogenic involvement that affect the superior laryngeal nerve and lead to hoarseness.

Keywords

• Electromyography
• larynx
• hoarseness
• superior laryngeal nerve