Relationship of botulinum dosage to duration of side effects and normal voice in adductor spasmodic dysphonia

Pharyngeal Motility Before and After Thyroarytenoid Muscle Botulinum Toxin Injection

Botulinum toxin type A (BTA) injection in intrinsic laryngeal musculature may result in dysphagia and consequent loss of quality of life (QOL) in a percentage of patients. This study aims to evaluate pharyngeal motility as a putative cause for this change in swallow quality in light of high-resolution manometry (HRM). Twenty patients (95% females, median age 66 years) underwent high-resolution manometry before and after BTA injection. Dysphagia was evaluated based on a QOL dedicated questionnaire (SWAL-QOL) before and after BTA injection. Pharyngeal motility at the topography of the vellum, epiglottis, and upper esophageal sphincter (UES) were recorded. Eleven (55%) subjects had worsened QOL after BTA injection. In patients with worsened QOL, UES extension decreased (p = 0.005), UES residual pressure increased (p = 0.02), UES basal pressure decreased (p = 0.04), and velopharynx contraction duration decreased (p = 0.04). UES residual pressure increased (p = 0.01), velopharynx peak pressure (p = 0.04) and upstroke (p = 0.007) decreased in patients with maintained QOL. There was no difference between groups when comparing pre-injection values. UES extension (p = 0.01) and UES maximum relaxation time (p = 0.03) was lower in the group with worsened QOL after BTA as compared to no change in QOL. Pharyngeal motility as measured by HRM was not a predictor for post procedure dysphagia and the changes in motility after BTA injection does not seem to be a strong contributor to dysphagia.

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.

Tratamento médico e fonoaudiológico da disfonia espasmódica: uma revisão bibliográfica

A disfonia espasmódica (DE) é um distúrbio vocal caracterizado por voz tensa-estrangulada, com quebras de sonoridade e que compromete a comunicação do indivíduo. O objetivo deste estudo é apresentar uma revisão bibliográfica dos tratamentos médico e fonoaudiológico proposto para a DE no período entre 2006 e 2010. Os tratamentos descritos foram: injeção de toxina botulínica (TB), miectomia, neurectomia, denervação e reinervação laríngea seletiva adutora, tireoplastia, miotermia tiroaritenóidea com radiofrequência, injeção de lidocaína, homeopatia e tratamento fonoaudiológico (fonoterapia). O uso de injeção de TB mostrou resultados que indicaram a satisfação dos pacientes tratados, embora alguns dos artigos apontassem a necessidade de reaplicação da toxina frequentemente, como desvantagem. Os procedimentos cirúrgicos foram considerados duradouros e indicados para os pacientes que não quiseram se submeter às aplicações de TB. Tais estudos, no entanto, apresentaram contingência de pacientes restrita e os resultados foram baseados, na maioria das investigações, no julgamento dos próprios pacientes sobre a sua qualidade vocal. Os tratamentos, com uso de lidocaína e homeopatia, mostraram resultados positivos em relação à qualidade vocal dos pacientes e foram sugeridos como uma opção, também, para aqueles que não gostariam de ser submetidos ao tratamento cirúrgico ou à aplicação de TB. Os poucos estudos que reportam fonoterapia assinalaram bons resultados quando a mesma foi associada à injeção de TB, mostrando a escassez de informações nesta área. Futuras pesquisas envolvendo a fonoterapia no tratamento da DE são necessárias.

Considerations for Initial Dosing of Botulinum Toxin in Treatment of Adductor Spasmodic Dysphonia

Objectives

To assess the effect on voice improvement and duration of breathiness based on initial dose of onabotulinum toxin A (BTX-A) in the management of adductor spasmodic dysphonia (SD) and to compare voice outcomes for initial bilaterally injected doses of 1.25 units (group A) vs 2.5 units (group B) of BTX-A.

Study Design

Case series with chart review of patients with adductor SD treated at a tertiary care facility from 1990 to 2011.

Setting

Academic subspecialty laryngology practice.

Methods

Demographic data (age and sex), voice rating, duration of voice improvement, and breathiness were evaluated and compared between groups A and B using the Student t test and χ2 analysis.

Results

Of 478 patients identified, 305 (223 in group A, 82 in group B) patients met inclusion criteria. The average age was 56.2 years in group A and 57.4 years in group B ( P = .5). The female to male ratio was 2.91 for group A vs 3.56 for group B ( P = .61). Good voice outcomes (grade 3 or 4) were reported by 91% of group A patients vs 94% of group B ( P = .75). The average duration of voice improvement was 99.7 days for group A and 108.3 days for group B ( P = .54). The average duration of breathiness was 10.88 days for group A vs 15.42 days for group B ( P = .02).

Conclusion

Patients injected with 1.25 units bilaterally had a statistically significant shorter duration of breathiness without a statistically significant difference in clinical effectiveness or voice outcome. It is therefore recommended that a relatively low initial BTX-A dose be used with subsequent titration to achieve improved voice outcomes.

[Neurolaryngology]

The neuroanatomy of voice and speech is complex. An intricate neural network is responsible for ensuring the main functions of the larynx: airway protection, cough and Valsalva production, and providing voice. Coordination of these roles is very susceptible to disruption by neurological disorders. Neurological disorders that affect laryngeal function include Parkinson's disease, stroke, amyotrophic lateral sclerosis, multiple sclerosis, dystonia and essential tremor. A thorough neurological evaluation should be routine for any patient presenting with voice complaints suggestive of neurogenic cause. Endoscopic visualisation of the larynx using a dynamic voice assessment with a flexible laryngoscope is a crucial part of the evaluation and ancillary tests are sometimes performed. Otolaryngologic evaluation is important in the diagnosis and treatment of neurological disorders that affect laryngeal function.

A Survey of Current Practices of Physicians who Treat Adductor Spasmodic Dysphonia in the U.S

We conducted a survey to determine the current practices of a subset of physicians in the United States who treat patients with adductor spasmodic dysphonia. Surveys were sent to 169 physicians listed in the National Spasmodic Dysphonia Association database, and responses were returned by 43 (25.4%). Almost all respondents (95.4%) indicated that they use botulinum toxin type A injections, either alone or in combination with other treatments, to treat adductor spasmodic dysphonia, and most (69.8%) inject the toxin under electromyographic guidance. However, there were wide variations in the amount of sterile saline used to reconstitute the toxin, the size of the initial dose, and the use of other treatment strategies.

Dosage changes in patients with long-term botulinum toxin use for laryngeal dystonia

OBJECTIVE: To investigate the dosage consistency of botulinum toxin injections in patients with long-term treatment for laryngeal dystonia.

STUDY DESIGN: Chart review.

SUBJECTS AND METHODS: Patients with laryngeal dystonia who had received at least 20 injections to the thyroarytenoid muscle were selected. Change of botulinum toxin dose, patient-reported effective weeks, and intervals between injections were investigated; data from the first five injections were excluded to eliminate initial dose titration.

RESULTS: Fifty-five patients with an average follow-up of 12.5 years were identified. Mean dose of botulinum toxin was 2.37 ± 1.6 U at the sixth injection; there was a decrease in mean dose over time, which became statistically significant at the 13th injection with a mean dose of 2.02 ± 1.16 U. Mean duration of good effect and treatment intervals showed no significant change over time.

CONCLUSION: Botulinum toxin dose needed for a constant response in treatment of laryngeal dystonia decreases over time, without any accompanying change in effective weeks and intervals.