Vocal outcome measures after bilateral posterior cricoarytenoid muscle botulinum toxin injections for abductor spasmodic dysphonia

Treatment Outcome Measures for Spasmodic Dysphonia: A Systematic Review

PURPOSE

This systematic review aims to identify instruments used to evaluate treatment outcomes for people with spasmodic dysphonia.

METHODS

Electronic database (PubMed, Cochrane Library, Embase, and CINAHL) searches and hand-searching identified studies that evaluated treatment approaches for spasmodic dysphonia which included pre and post outcome data.

RESULTS

A total of 4714 articles were retrieved from searching databases; 1165 were duplicates. Titles and abstracts of 3549 were screened, with 171 being selected for full-text review. During full-text review, 101 articles were deemed suitable for inclusion. An additional 24 articles were identified as suitable for inclusion through hand-searching of reference lists. Data was extracted from 125 studies, identifying 220 outcome measures. As per the World Health Organization's International Classification of Functioning (ICF), the majority measured body functions (n = 212, 96%). Outcomes that explored communication and participation in everyday life and attitudes towards communication (ie, activity and participation domains) were infrequent (n = 8; 4%). Quality of life, a paradigm outside of the scope of the ICF, was also captured by four outcome measures. No instruments evaluating communication partners' perspectives were identified.

CONCLUSIONS

Currently there is no unified approach to the measurement of outcomes in SD treatment research. Development and implementation of a core outcome set is recommended to facilitate improved understanding of the efficacy of current and new treatment options.

Guidelines for the Use of Botulinum Toxin in Otolaryngology From the Korean Society of Laryngology, Phoniatrics and Logopedics Guideline Task Force

The Korean Society of Laryngology, Phoniatrics and Logopedics created a task force to establish clinical practice guidelines for the use of botulinum toxin (BT) in otolaryngology. We selected 10 disease categories: spasmodic dysphonia, essential vocal tremor, vocal fold granuloma, bilateral vocal fold paralysis, Frey's syndrome, sialocele, sialorrhea, cricopharyngeal dysfunction, chronic sialadenitis, and first bite syndrome. To retrieve all relevant papers, we searched the CORE databases with predefined search strategies, including Medline (PubMed), Embase, the Cochrane Library, and KoreaMed. The committee reported 13 final recommendations with detailed evidence profiles. The guidelines are primarily aimed at all clinicians applying BT to the head and neck area. In addition, the guidelines aim to promote an improved understanding of the safe and effective use of BT by policymakers and counselors, as well as in patients scheduled to receive BT injections.

Safety and Effectiveness of OnabotulinumtoxinA in Patients with Laryngeal Dystonia: Final Report of a 52-Week, Multicenter Postmarketing Surveillance Study

This postmarketing surveillance study was conducted to evaluate the safety and effectiveness of onabotulinumtoxinA in Japanese patients with laryngeal dystonia (LD). Patients receiving onabotulinumtoxinA for the first time were enrolled and observed for up to 12 months following the first injection. Safety assessment included adverse drug reactions (ADRs), and effectiveness assessments included the Voice Handicap Index-10 (VHI-10) and physician's global assessment (PGA). ADRs were observed in 48 (5.8%) of 834 patients in the safety analysis set, including dysphonia in 43 (5.2%) patients and dysphagia in 7 (0.8%) patients. The change in total VHI-10 score (mean) in 790 patients included in the effectiveness analysis set showed that improvement in adductor LD peaked at 2 months after the first injection, while patients with abductor or mixed LD showed a gradual attenuation of effect 2-4 weeks post-injection. The change in total VHI-10 score in subsequent injections was generally similar to that following the first injection. The overall effectiveness rate according to the PGA was 93.4% (738/790 patients). The results demonstrate that onabotulinumtoxinA is a well-tolerated and effective treatment for LD in real-world clinical practice.

Botulinum Neurotoxin Therapy in the Clinical Management of Laryngeal Dystonia

Laryngeal dystonia (LD), or spasmodic dysphonia (SD), is a chronic, task-specific, focal movement disorder affecting the larynx. It interferes primarily with the essential functions of phonation and speech. LD affects patients' ability to communicate effectively and significantly diminishes their quality of life. Botulinum neurotoxin was first used as a therapeutic agent in the treatment of LD four decades ago and remains the standard of care for the treatment of LD. This article provides an overview of the clinical application of botulinum neurotoxin in the management of LD, focusing on the classification for this disorder, its pathophysiology, clinical assessment and diagnosis, the role of laryngeal electromyography and a summary of therapeutic injection techniques, including a comprehensive description of various procedural approaches, recommendations for injection sites and dosage considerations.

Chemodenervation of the Larynx

Botulinum neurotoxin (BoNT) has existed for thousands of years; however, it was not medically utilized until investigations into its therapeutic use began in sincerity during the late 1970s and 1980s. This, coupled with the reclassification of spasmodic dysphonia as a focal dystonia, led to the use of chemodenervation for this disorder, which has since become a refined technique. Indeed, due to its safety and efficacy, BoNT has been investigated in multiple neurolaryngology disorders, including spasmodic dysphonia, vocal tremor, and muscle tension dysphonia. BoNT has been shown to be a useful and safe adjunct in the treatment for these disorders and may reduce or eliminate oral pharmacotherapy and/or prevent the need for a surgical intervention. We present the historical background, development, proposed mechanisms of action, uses, and techniques for administering BoNT for laryngeal disorders, with a particular focus on spasmodic dysphonia.

Liquid-type Botulinum Toxin Type A in Adductor Spasmodic Dysphonia: A Prospective Pilot Study

OBJECTIVES

Botulinum toxin (BTX) has been widely used to treat adductor spasmodic dysphonia (ADSD). Most commercially available forms of BTX require reconstitution before use, which may increase the risk of contamination and requires careful titration. Recently, a liquid-type BTX type A (BTX-A) has been developed, which should simplify the procedure and enhance its efficacy. Herein, we present a prospective pilot study to investigate the efficacy and safety of liquid-type BTX-A in the treatment of ADSD.

METHODS

Twenty-six consecutive liquid-type BTX-A injections were performed in 12 patients with ADSD. We included as a control group 34 consecutive patients with ADSD who had previously undergone 52 vocal fold injection procedures with freeze-dried-type BTX-A.

RESULTS

All patients in both groups had improvement of symptoms related to ADSD and period of normal voice. Most patients experienced breathiness, and the onset time, the peak response time, and the duration of breathiness were similar in both groups. The duration of effect (days) was 96.96 ± 18.91 and 77.38 ± 18.97 in the freeze-dried-type and the liquid-type groups, and the duration of benefit (days) was 80.02 ± 18.24 and 62.69 ± 19.73 in the freeze-dried-type and the liquid-type groups. To compare the efficacy between the freeze-dried-type and the liquid-type BTX-A, the sessions of the unilateral vocal fold injection were included and were categorized as group A (1 ~ 2 units BTX-A) and group B (2 ~ 3 units BTX-A), according to the dose per vocal fold. There was no significant difference of effect time between freeze-dried-type and liquid-type BTX-A groups. No adverse events related to BTX or vocal fold injection were reported.

CONCLUSIONS

Liquid-type BTX-A is safe and effective for the treatment of spasmodic dysphonia. With the advantages of simple preparation, storage, and reuse and animal protein-free constituents, liquid-type BTX-A may be a good option in the treatment of spasmodic dysphonia.

Treatment for spasmodic dysphonia: limitations of current approaches

PURPOSE OF REVIEW

Although botulinum toxin injection is the gold standard for treatment of spasmodic dysphonia, surgical approaches aimed at providing long-term symptom control have been advancing over recent years.

RECENT FINDINGS

When surgical approaches provide greater long-term benefits to symptom control, they also increase the initial period of side effects of breathiness and swallowing difficulties. Recent analyses of quality-of-life questionnaires in patients undergoing regular injections of botulinum toxin demonstrate that a large proportion of patients have limited relief for relatively short periods due to early breathiness and loss-of-benefit before reinjection.

SUMMARY

Most medical and surgical approaches to the treatment of spasmodic dysphonia have been aimed at denervation of the laryngeal muscles to block symptom expression in the voice, and have both adverse effects as well as treatment benefits. Research is needed to identify the central neuropathophysiology responsible for the laryngeal muscle spasms in order target treatment towards the central neurological abnormality responsible for producing symptoms.