Laryngeal and Vocal Changes During Vagus Nerve Stimulation in Epileptic Patients

Left vagus nerve stimulation (VNS) by means of an implanted electrode has proven to reduce seizure frequency in epileptic patients with medically refractory seizures. This technique is now widely applied over the world. Voice changes appear to be one of the major side effects. The morphodynamic changes in the larynx and the acoustic impacts have been analyzed in detail in 7 implanted patients. Basic vagus stimulation is well tolerated. Extra stimulation induces an adductory spasm of either the ipsilateral vocal fold or the vestibular fold. The result, when the patient phonates, consists of a slight increase of F0 as well as a moderate increase of random period perturbation, but there is no evidence for the occurrence of "bifurcations." Further, as the glottic closure remains sufficient, there is no increase in turbulent noise. The lack of increase in turbulent noise and the lack of "bifurcations" appears to clearly differentiate a spasmodic contraction of the vocal cord from a unilateral vocal fold paralysis.     

Positive Effects of Manual Circumlaryngeal Therapy in the Treatment of Muscle Tension Dysphonia (MTD): Long Term Treatment Outcomes

IntroductionManual circumlaryngeal therapy (MCT) aims to correct laryngeal position and relax (para) laryngeal and cervical muscles resulting in improved voice quality. The goal of the current study was to further verify long-term effects of MCT in the treatment of Muscle Tension Dysphonia (MTD) patients based on acoustic findings and perceptual judgments.MethodTwenty-eight adult female patients who had been referred to the speech therapy clinic of Khatam Hospital, Zahedan city, participated in this study. Manual circumlaryngeal therapy was undertaken. There were 15 therapy sessions, three sessions per week, each with duration of 30 minutes. Pre- and post-treatment audio recordings of sustained vowels, selected sentences, and connected speech samples were submitted to auditory-perceptual and acoustical analysis to assess the long-term (6-months) effects of the 15 treatment program.ResultsAcoustically, Harmonic to Noise Ratio (HNR) increased and perturbation (Jitter and Shimmer) measures decreased, and perceptually, the subjective CAPE-V ratings improved in all patients.ConclusionThese results suggest that MCT can be an effective method for voice rehabilitation in patients with MTD and the changes due to the therapy were persistent over a 6-month duration following the termination of treatment sessions.