Botulinum Toxin Type A for Treating Voice Tremor

Abstract

Background: Voice tremor, like spasmodic dysphonia and other tremor disorders, may respond to botulinum toxin type A injections.Objective: To evaluate the safety and efficacy of botulinum toxin type A injections as treatment for voice tremor.Design: A randomized study of 3 doses of botulinum toxin type A with 6 weeks of follow-up.Setting: A single-site tertiary care center.Participants and Methods: Thirteen subjects (11 women, 2 men; mean age, 73 years) with voice tremor and no spasmodic dysphonia or head, mouth, jaw, or facial tremor were entered into this study. Patients received 1.25 U (n = 5), 2.5 U (n = 5), or 3.75 U (n=3) of botulinum toxin type A in each vocal cord. All patients were evaluated at baseline and postinjection at weeks 2, 4, and 6. Main Outcome Measures:The primary outcome measure was the patient tremor rating scale, with secondary measures including patient-rated functional disability, response rating scale, independent randomized tremor ratings, and acoustical measures.Results: All patients at all dose levels noted an effect from the injection. The mean time to onset of effect was 2.3 days (range, 1-7 days). For all patients combined, mean tremor severity scale scores (rated by patients on a 5-point scale) improved 1.4 points at week 2, 1.6 points at week 4, and 1.7 points at week 6. Measures of functional disability, measures of the effect of injection, independent ratings of videotaped speech, and acoustic measures of tremor also showed improvement. The main adverse effects at all doses were breathiness and dysphagia. Conclusion:Voice tremor improves following injections of botulinum toxin type A.

Laryngeal Tremor: Co-Occurrence with Other Movement Disorders

“…Botulinum toxin injection is typically one of the first treatments used for both diseases, while more invasive surgical treatments are reserved for severe cases. Procedures like deep brain stimulation may help patients with severe LT, whereas treatments such as myectomy of the thyroarytenoid and lateral cricoarytenoid, proposed by Koufman et al, may only benefit patients with SD [ 20 , see also 15,18,19 ].…”

Perception of Vocal Tremor During Sustained Phonation Compared With Sentence Context

“…27,28 In contrast, a more localized application of pharmaceutical treatment via Botulinum toxin (ie, Botox Allergen, Inc., Irvine, CA) injection has been reported as beneficial in reducing symptoms in as many as 80% of individuals with vocal tremor involving the larynx. 3,22,[29][30][31][32][33] Although generally beneficial in reducing vocal tremor and effort levels during speaking, Botox injections have also been associated with excessive breathiness and impaired swallowing for up to 6 weeks following treatment in some individuals. 22,29,32,33 These individuals may consequently choose to discontinue Botox treatment.…”

An Update on the Neurologic Applications of Botulinum Toxins

“…One class II study involving 10 patients with head tremor did not show significant improvement [42]. A class IV open-label study of Botox in 13 subjects with isolated vocal tremor with no spasmodic dysphonia showed a beneficial effect in all patients assessed at 6 weeks post injection [43].…”