Effects of transcutaneous electrical stimulation on vocal folds adduction

Effect of Electrical Stimulation on the Treatment of Dysphonia: A Systematic Review

OBJECTIVES

The aim of this study was to review systematically the literature and to investigate the effects of electrical stimulation in treating dysphonia.

STUDY DESIGN

This is a systematic review.

METHODS

The publications indexed on the MEDLINE, LILACS, PubMed, Web of Science, and SciELO databases were searched. Original articles with experimental, clinical trial and randomized studies involving a control group and approaching dysphonia treatment with electrical stimulation in humans, regardless of age, gender, or race were included. Those excluded were theses, editorials, comments and opinions, reflexive articles, case studies, experimental studies with animals, models, projects, reports and technical reports, and review articles, as well as articles approaching other alterations, not related to dysphonia.

RESULTS

Eleven articles were found and it evaluated the effects of neuromuscular electrical stimulation (NMES) and transcutaneous electrical nerve stimulation on dysphonia caused by vocal fold paralysis, spasmodic dysphonia, behavioral dysphonia, and in patients with vocal fold nodules. The methodological analysis of the articles through the PEDro scale resulted in a mean score of 5.18; the studies were classified as either high quality (N = 3) or fair quality (N = 8). The results indicated that electrical stimulation had a therapeutic effect on various aspects of dysphonia. However, due to the high risk of bias and the heterogeneity of the studies, it is not possible to state the effectiveness of electrical stimulation in treating dysphonia.

CONCLUSION

Using electrical stimulation as an evidence-based conventional rehabilitation therapy in the treatment of dysphonia cannot yet be done.

Selective Electrical Surface Stimulation to Support Functional Recovery in the Early Phase After Unilateral Acute Facial Nerve or Vocal Fold Paralysis

This article addresses the potential clinical value of surface electrical stimulation in the acute phase of denervation after the onset of facial nerve or recurrent laryngeal nerve paralysis. These two nerve lesions are the most frequent head and neck nerve lesions. In this review, we will work out several similarities concerning the pathophysiology features and the clinical scenario between both nerve lesions, which allow to develop some general rules for surface electrical stimulation applicable for both nerve lesions. The focus is on electrical stimulation in the phase between denervation and reinnervation of the target muscles. The aim of electrostimulation in this phase of denervation is to bridge the time until reinnervation is complete and to maintain facial or laryngeal function. In this phase, electrostimulation has to stimulate directly the denervated muscles, i.e. muscle stimulation and not nerve stimulation. There is preliminary data that early electrostimulation might also improve the functional outcome. Because there are still caveats against the use of electrostimulation, the neurophysiology of denervated facial and laryngeal muscles in comparison to innervated muscles is explained in detail. This is necessary to understand why the negative results published in several studies that used stimulation parameters are not suitable for denervated muscle fibers. Juxtaposed are studies using parameters adapted for the stimulation of denervated facial or laryngeal muscles. These studies used standardized outcome measure and show that an effective and tolerable electrostimulation of facial and laryngeal muscles without side effects in the early phase after onset of the lesions is feasible, does not hinder nerve regeneration and might even be able to improve the functional outcome. This has now to be proven in larger controlled trials. In our view, surface electrical stimulation has an unexploited potential to enrich the early therapy concepts for patients with unilateral facial or vocal fold paralysis.

Laryngeal Adductor Reflex Movement Latency Following Tactile Stimulation

OBJECTIVE

To measure the latency of laryngeal adductor reflex (LAR) motion onset at 2 laryngopharyngeal subsites using calibrated aesthesiometers.

STUDY DESIGN

Cross-sectional.

SETTING

Academic institution.

METHODS

Twenty-one asymptomatic, healthy subjects (11 male, 10 female) underwent laryngopharyngeal sensory testing with tactile stimuli delivered to the aryepiglottic fold and medial pyriform sinus using 30-mm Cheung-Bearelly monofilaments (4-0 and 5-0 nylon sutures) via channeled flexible laryngoscope. The LAR onset latency, defined as the first visual detection of ipsilateral vocal fold adduction following tactile stimulation, was measured with frame-by-frame analysis of video recordings.

RESULTS

The overall mean LAR latency across both subsites and stimulation forces was 176.6 (95% CI, 170.3-183.0) ms, without significant difference between subsites or forces. The critical value for LAR response latency prolongation at the .01 significance level was 244 ms. At 30 frames/s video capture resolution, LAR response latency ≥8 frame intervals would indicate abnormal prolongation.

CONCLUSION

Aesthesiometer-triggered LAR latency appears to be invariant over an 8.7-dB force range and between the aryepiglottic fold and medial pyriform sinus subsites in controls. Laryngeal adductor reflex latency incongruences between stimulation forces or laryngopharyngeal subsites may serve as pathophysiological features to dissect mechanisms of upper aerodigestive tract disorders.

LEVEL OF EVIDENCE

Level 3B.

Functional electrostimulation associated with phonation in women without vocal disorders

PURPOSE

To verify the immediate effect of the Excitomotor Electrical Current, called Functional Electrical Stimulation (FES), on vocal quality, Maximum Phonation Time (MPT) and possible discomfort, in women without vocal alteration, with application at Maximum Supported Intensity (MSI) and associated with phonation.

METHODS

Experimental study with 20 normophonic adult women. They emitted the sustained vowel / a / and then it was applied to FES during emission of the same vowel. There were five series with three minutes of emission each, interspersed with passive rest. The electrical stimulus was at the MSI by the participant, adjusted by series. Before and after the emissions the voices were recorded and the MPT and the intensity of the stimuli were collected. The vocal quality was rated by judges. Statistical analysis made it possible to compare pre and post emission / electrostimulation data in each phase. Qualitative analysis was performed based on self-reported symptoms.

RESULTS

There was no difference in vocal quality and MPT between pre and post moments in both phases. The difference between MSI and stimulus perception intensity was greater in series 1 than in series 2. There was an increase in MSI in series 5 compared to series 1. No significant negative symptoms or within 48h after procedures were reported.

CONCLUSION

The FES at MSI, associated with phonation, did not generate an immediate change in vocal quality, in the MPT or self-reported discomforts by women without vocal alteration, even with a gradual increase in the stimulus, series by series.

Self-rated vocal complaints relationship to Vocal Tract Discomfort and Singers Voice Handicap Index in Iranian religious singers

PURPOSE

The religious singing is a popular group of professional voice users in Iran which is performed in a sadness form to persuade the audiences to cry and think to holy persons. This style has its own unique vocal demands and abuses. Therefore, the present study, for the first time, aimed to investigate the prevalence of self-reported vocal complaints, vocal discomfort symptoms, and its effects on the vocal-related life of the Iranian religious singers.

METHODS

In a cross-sectional study, 62 religious singers (28 women, 34 men) completed Singers Voice Handicap Index (SVHI), Vocal Tract Discomfort (VTD), and also a non-standard self-rated vocal complaint question. Spearman correlation test was applied to analyze correlations. Furthermore, 39 non-singers (18 women, 21 men) as a control group participated in this study.

RESULTS

The religious singer's mean score of the SVHI test was 34.84 (SD = 24.89). According to the self-rated vocal complaint question, almost 80% of the participants reported mild to the severe vocal complaints that was significantly higher than control group which was about 10%. The self-rated complaints indicated a significant positive correlation with the SVHI and the VTD reported by singers (p ≤ 0.001). The mean scores of the VTD symptoms in singers were significantly greater than control group. There was also a significant positive correlation between the two VTD and SVHI tests (p ≤ 0.001).

CONCLUSION

Religious singers are at a great risk of developing voice problems. Therefore, their vocal demands and requirements need to be followed precisely. The SVHI and VTD tests should also be considered as two efficient tools for religious singers.

Rol de los agentes físicos en la rehabilitación vocal: una revisión de la literatura

Los agentes físicos son elementos naturales o artificiales que se aplican para el tratamiento de determinados síntomas o patologías. En la rehabilitación vocal su estudio es un área emergente, donde las revisiones sistemáticas y los meta-análisis son escasos. Esto, muchas veces, dificulta la toma de decisiones y la correcta elección por parte del clínico.  El objetivo de este trabajo fue analizar el rol de los agentes físicos en la rehabilitación vocal. Se realizó una revisión de la literatura a través de la búsqueda de artículos en las bases de datos PubMed, EBSCOHost y Scielo. Se establecieron criterios de elegibilidad según tipo, año y características de los estudios. Se evaluaron 603 artículos, de los cuales, luego del análisis de su título, abstract y del cumplimiento de los criterios de elegibilidad, se seleccionaron 16. Se entregan resultados en base a la cantidad de participantes, nivel de evidencia, tipo y configuración del agente físico, procedimientos e instrumentos de evaluación y beneficios obtenidos. Los agentes físicos de mayor utilización en la clínica vocal son la electroterapia (TENS y NMES) y la laserterapia. En general, estos actúan como coadyuvantes en la terapia vocal. La TENS reduce el dolor, la tensión laríngea y la percepción de voz apretada durante la fonación. La NMES beneficia la activación neuromuscular de las cuerdas vocales y el uso de láser permite la recuperación de los tejidos laríngeos posterior a tareas de sobrecarga.

History of Cranial Nerve-Implanted Stimulators in Otolaryngology

This article aims to clearly understand the historical development of cranial nerve-implanted stimulators in otolaryngology. The authors also discuss cranial nerve history; initial theory of the functional concept of animal spirit; electrical nerve impulse theory; first electrical otolaryngology cranial nerve stimulation devices; and the development of implanted stimulators.