Comparison of botulinum toxin and propranolol for essential and dystonic vocal tremors

OBJECTIVES: Vocal tremors, which cause social difficulties for patients, may be classified as resting or action tremors. Of the vocal action tremors, essential and dystonic tremors are the most common. Botulinum toxin and oral medications have been used to treat vocal tremors, but no comparative clinical trials have been performed. The aim of this study was to compare the effects of botulinum toxin injection and the oral administration of propranolol in the treatment of essential and dystonic vocal tremors. METHODS: This clinical trial recruited 15 patients, divided into essential and dystonic vocal tremor groups. Patients in both groups received successive treatment with botulinum toxin and propranolol. The treatments were administered at different times; the order of treatment was randomly selected. Patients were assessed with flexible nasofibrolaryngoscopy and with perceptual and acoustic voice evaluations. A statistical significance level of 0.05 (5%) was used. RESULTS: Botulinum toxin produced statistically significant improvements in perceptual measures of vocal instability in patients with dystonic vocal tremors compared with baseline values and treatment with propranolol. The acoustic measure of variability in the fundamental frequency was significantly lower in patients with dystonic vocal tremors after treatment with botulinum toxin. CONCLUSION: Essential and dystonic vocal tremors responded differently to treatment. Dystonic vocal tremors responded significantly to treatment with botulinum toxin but not oral propranolol. Essential vocal tremors did not respond significantly to either treatment, perhaps due to the small number of patients, which is a limitation of this research.

Distonia laríngea: relato de caso e tratamento com toxina botulínica / Laryngeal dystonia: case report and treatment with botulinum toxin

Distonia laríngea, ou disfonia espasmódica, é caracterizada por contrações involuntárias e inapropriadas da musculatura responsável pela fonação, sendo a do tipo adutora a mais comum. Caracteriza-se por quebras fonatórias, sendo seu diagnóstico confirmado por videolaringoestroboscopia. O tratamento de escolha é feito com a aplicação direta de toxina botulínica nos músculos responsáveis pelo movimento incoordenado. O objetivo desse trabalho é relatar o caso de uma paciente com diagnóstico de distonia laríngea do tipo adutora, tratada com toxina botulínica e discutir as vantagens e observações descritas na literatura a respeito desse tratamento.

Laryngeal dystonia or spasmodic dysphonia is characterized by involuntary and innapropiate spasms of vocal muscles, having the adductor type as the most common one. It is chacterized by strain-strangled voice with pitch breaks. Diagnosis is made by means of videolaryngostroboscopic exam. The treatment of choice is done with botulinum toxin directly injected in the muscles responsible for the mismatched movement. The aim of this study is to report on an adductor- type dysphonia patient and to discuss the advantages and observations about this treatment reported in the literature.

Laryngeal electromyography in movement disorders: preliminary data

Este estudo descreve dados preliminares de eletromiografia laríngea (LEMG) e tratamento com toxina botulínica em pacientes com disfonia associada a distúrbios do movimento. Foram estudados 25 pacientes, 19 com distonia laríngea ou disfonia espasmódica, 5 com tremor vocal e 1 com síndrome de Gilles de la Tourette. LEMG realizada com eletrodos monopolares, antes da administração de toxina botulínica, foi compatível com distonia em 14 pacientes (normal em 5), sugeriu tremor essencial em 3 e Parkinson em 2. Os diferentes padrões de LEMG e melhora considerável obtida com administração de toxina botulínica instituíram LEMG como rotina no ambulatório de distúrbios do movimento da UNICAMP.