Comparison of voice therapy and selective electrical stimulation of the larynx in early unilateral vocal fold paralysis after thyroid surgery: A retrospective data analysis

Volitional and Non-volitional Devices Used in Voice Therapy and Training: A Scoping Review-Part A

OBJECTIVE

To map the volitional and non-volitional devices used by speech and language pathologists (SLPs) in voice training and therapy and characterize their use in research on voice interventions.

METHODS

This scoping review is the first part of a larger study. The electronic search was carried out by mapping the references in PubMed/Medline, LILACS/BVS, Scopus, Web of Science, EMBASE, and the Cochrane Library, and the manual search was carried out in the grey literature. Two blind independent reviewers selected and extracted data; divergences were solved by consensus. The data extracted in this part of the study were the authorship and year of publication, country, study design, sample characteristics, intervention modality, ingredient, target, mechanism of action, dosage, and outcome measures. They were addressed with descriptive analysis.

RESULTS

Publications that use devices as ingredients are mostly from the last two decades, mainly carried out in the United States of America and Brazil, in adults of both sexes with behavioral dysphonia. Forty-two types of devices were used, many of them with similar approaches but different nomenclatures. Most devices were used voluntarily, focusing on vocal function, and aiming to increase source and filter interaction. Most studies used silicone tubes. The most reported technical specification to apply the ingredient was surface electrodes on the neck. Device dosage was time-controlled, and the most used outcomes were self-assessment and acoustic analysis.

CONCLUSION

Devices are currently used as ingredients in vocal interventions, with a greater focus on increasing the source and filter interaction, associated with silicone tubes (the most used devices in these studies), which have been dosed with performance time. Outcomes were measured with self-assessment instruments.

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.

Comparison of voice therapy and selective electrical stimulation of the larynx in early unilateral vocal fold paralysis after thyroid surgery: A retrospective data analysis

Objectives

The goal of the retrospective study was to investigate the 3‐month‐outcome after treatment of patients with early unilateral vocal fold paralysis (UVFP) with either standard voice therapy (VT) or selective electrical stimulation of the larynx (SES).

Design

Non‐randomised retrospective study.

Setting

1519 patients who underwent thyroid surgery between 2015 and 2018 were analysed according vocal fold mobility; UVFP patients were treated either by VT or SES.

Participants

51 UVFP patients.

Main outcome measures

51 UVFP patients have been advised regarding treatment options like either VT (group 1) or SES (group 2). The patients of group 1 (n = 26) and 2 (n = 25) were re‐assessed up to 3 months post‐operatively regarding UVFP persistence/recovery and perceptive voice sound quality. At follow‐ups, perceptual analysis of voice sound (using roughness=R/breathiness=B/hoarseness=H scale) and endoscopic laryngoscopy have been performed. Position of immobile vocal fold, shape of glottal closure and RBH parameters have been considered for statistical analyses.

Results

Restitution of UVFP with regular respiratory vocal fold mobility of both vocal folds occurred in 53.8% of group 1 (VT), and in 40.0% of group 2 (SES) after 3 months of therapy between both groups. No difference could be seen for RBH, type of glottal closure and position of ailing vocal folds in patients with persisting UVFP within both groups and between the groups.

Conclusions

The study reveals that SES can achieve similar functional outcome in early UVFP. Thus, it should be considered as an equivalent therapy alternative to VT for treatment of early UVFP patients since no significant difference in vocal outcome and glottal configuration between the two groups could be demonstrated.