Medical treatment and speech therapy for spasmodic dysphonia: a literature review

^ISpeech Pathologist; PhD Professor at the Department of Speech Pathology, UNESP, Marilia, São Paulo, Brazil; PhD in Education from UNESP

^IISpeech Pathologist; PhD Professor at the Department of Speech Pathology, UNESP, Marilia, São Paulo, Brazil; PhD in Communication Sciences and Disorders from the University of Florida

^IIISpeech Pathologist; B.A. in Speech Pathology from UNESP Marília, São Paulo, Brazil

^IVSpeech Pathologist; PhD Professor at the Department of Speech Pathology, UNESP, Marilia, São Paulo, Brazil; PhD in Education from UNESP

^VMedical Doctor; Assistant Professor at the Department of Speech Pathology, UNESP, Marilia, São Paulo, Brazil; Master's Degree

Correspondence

ABSTRACT

Spasmodic dysphonia (SD) is a voice disorder characterized by a strained-strangled voice, with sound breaks and has implications in one's communication. The purpose of this study is to present a bibliographic review of the speech therapy and medical treatment suggested for SD from 2006 to 2010. The speech therapy and medical treatments described are: botulinum toxin injection, myectomy, neurectomy, denervation and reinnervation selective laryngeal adductor, thyroplasty, radiofrequency thyroarytenoid myothermy, injection of lidocaine, homeopathy and speech therapy. The use of botulinum toxin injection showed results that indicated the satisfaction of the patients who were treated, although some of the articles presented the frequent need of reapplication of the toxin as a disadvantage. The surgical procedures were considered long-lasting and indicated to patients who didn't want to get botulinum toxin injections. The studies, however, presented a restricted contingency of patients, and the outcomes in many studies were based in the patient's own judgment on his/her voice quality. The treatments using lidocaine and homeopathy had positive results in relation to the voice quality of the patients and were suggested as an option for those who wouldn't like to undergo surgical treatment or have botulinum toxin injection. The few studies which discourse on voice therapy presented good results in association with botulinum toxin injection, showing the shortage of information in this field. A study on the literature review pointed out the need of developing researches to help us understand the neurological functioning in spasmodic dysphonia. Future study involving speech therapy in the treatment of ED is still necessary.

Keywords: Dysphonia; Spastic Dysphonia; Dystonia

RESUMO

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.

Descritores: Disfonia; Disfonia Espástica; Distonia

INTRODUCTION

First described by Traube in 1871, spasmodic dysphonia (SD) was classified as a spastic form of nervous hoarseness. This disorder was discussed in literature as two types of spastic dysphonia: adductor spasmodic dysphonia (AdSD) and abductor spasmodic dysphonia (AbSD)¹. Adductor spasmodic dysphonia is characterized by the strained-strangled voice, with interruption in word production or difficulty in starting². Abductor spasmodic dysphonia was described as maintaining normal vocal quality followed by moments of breathy or whispery voice¹. The term spastic dysphonia was subsequently discussed in literature and considered inadequate because it is not an alteration related to injury in the pyramidal or extrapyramidal tract³. Currently SD is classified as a focal laryngeal dystonia with a neurological etiology².

The standard treatment for SD, according to that presented in literature, is the injection of type A botulinum toxin (BT-A)^4,5 which can be combined with speech therapy³. Speech therapy as the only proposed treatment is considered ineffective mainly due to the fact that emotional states influence the control of speech production in patients diagnosed with SD⁷. However, studies show that following BT injection, speech therapy may help in prolonging its effectiveness, providing longer intervals between applications^8-10.

Several other forms of treatment (medical and/or surgical) for SD were presented in the literature, however, none showed lasting effectiveness. Despite the various proposals presented for surgical treatment, literature indicates that some patients with SD go to speech therapy in an attempt to minimize communication disorders when other treatments are not effective^7,11.

The search for treatment options for SD is caused by the need to find a better quality of life for the patients. Given the difficulty in obtaining conclusive information from literature about treatments available for SD, an updated search in recently published articles is essential in determining the best approach in the treatment and prognosis of this devastating communication disorder. Thus, this study aims to review literature on medical and speech pathology treatment for SD from the period between 2006 and 2010.

METHOD

The study was conducted by searching national and international journal articles available in the databases Lilacs, Medline, and Scielo, which after careful analysis were incorporated into the study.

The criteria used for inclusion were articles that presented data for SD treatment (medical and/or speech therapy) reported within the last five years, i.e. between 2006 and 2010. Articles on SD that included investigation with animals were disregarded.

In the search for articles, terms related to the theme "spasmodic dysphonia" were chosen and found in the Health Sciences Descriptors (HSD). These terms were used in isolation and cross reference as shown in Figure 1. The filters "year of publication" and "word" were used in each search. And with the database Medline it was possible to use the filter "subject description", which allowed the search for the terms "voice", "focal dystonia" and "spastic dysphonia".

Figure 1 - List of words and subject descriptors used in the search

LITERATURE REVIEW

A total of 3833 articles were found in the survey of the databases Scielo, Lilacs, and Medline. Each article was presented in one or more databases.

From the analysis of the abstracts of these articles, we excluded those that had previously been selected in another database, those that did not meet the inclusion criteria, and also those from journals that did not provide the full article. Thus, we included 30 articles related to the study. These articles reported on treatment for SD by means of medical and speech pathological procedures with: (a) 11 (37%) articles on BT injection; (b) 10 (33%) on surgical procedures, such as myectomy (2, 7%), neurectomy (2, 7%), selective laryngeal adductor denervation and reinnervation (1, 3%), thyroplasty (4, 13%), and thyroarytenoid myothermy (1, 3%); (c) 2 (7%) on other medical treatments, such as homeopathy and lidocaine injection; and (d) 1 (3%) speech therapy. In addition to these, there were 6 (20%) literature review articles on the treatment of SD.

The information on the proposed treatments for SD, as shown in the literature, is summarized below.

Botulinum toxin is a protein produced by Clostridium botulinum bacteria with a potent neurotoxic action that blocks the release of acetylcholine from nerve endings at the neuromuscular joint. BT has been a treatment option for SD since the 1980s. The injection of BT into the intrinsic muscles of the larynx results in a temporary paresis or paralysis of the injected muscle. The toxin may be injected into one or both vocal folds simultaneously.

Several injection techniques may be used for BT, some of which are performed with the support of percutaneous electromyography or nasalaryngoscopy. The injection of BT is usually carried out in the thyroarytenoid muscle (TA)⁴, however there are also reports of injection in other laryngeal muscles, such as the lateral cricoarytenoid muscle (LCA).

One of the drawbacks of BT is the fact that the effect is temporary and it is necessary to reapply every three to six months. There is also the possibility of the body developing antibodies against BT which reduces its effectiveness. The following complications have been reported regarding the use of BT: transient dysphonia, glottic incompetence with an extremely hoarse voice, dysphagia, and asthenia.

Surgical treatments

The five reported surgical procedures include: myectomy, neurectomy, laryngeal denervation and reinnervation, thyroplasty, and radiofrequency thyroarytenoid myothermy.

Myectomy

The treatment with myectomy has been described since the 1990s. The surgical procedure is performed with an incision on the lateral surface of the vocal fold which exposes the TA muscle, followed by resection. This surgical treatment is irreversible and, in consequence, has the advantage of maintaining the long-term positive effect. Studies have shown that the TA muscle does not regenerate after resection¹².

Myectomy of the TA and LCA muscle may be performed with local anesthesia and intravenous sedation so that the voice and function of the vocal folds may be evaluated during the procedure¹³.

Neurectomy of the thyroarytenoid branch of the inferior laryngeal nerve associated with the partial myectomy of the TA muscle

Upon completion of the partial myectomy of the TA muscle with CO₂ laser, there is the sectioning by electrocoagulation of the thyroarytenoid branch of the recurrent laryngeal nerve (RLN), located between the internal perichondrium of the thyroid cartilage and the fascia of the TA and LCA muscles. The procedure described by the authors is performed in both vocal folds¹⁴.

Selective laryngeal adductor denervation and reinnervation

Selective adductor denervation interrupts the abnormal neural signals to the TA and LCA muscles. The adductor branch of the RLN is divided at its insertion in the TA and LCA muscles and the proximal stump is exteriorized from the larynx to prevent the regeneration of axons in this anatomical structure. The ansa cervicalis of the cervical nerve is then anastomosed to the distal stump of the TA to maintain muscle tone and volume and also prevent the regeneration of axons in the RLN endplates of the TA and LCA muscles¹⁵.

Thyroplasty

Type II thryoplasty, as described in the consulted literature, is carried out with local anesthesia followed by a midline incision of the thyroid cartilage holding the underlying tissue intact. During speech, the edges of the cartilage are separated from 2 to 6 mm, average 4 mm, to verify any voice change^16,17. A variety of material has been described for securing the edges of cartilage, such as pieces of silicon or cartilage, and titanium plates and bridges above and below the anterior commissure^16-18.

Radiofrequency thyroarytenoid myothermy

This procedure involves the insertion of a bipolar radiofrequency probe at two points of the vocal folds, one in the membranous portion and the other in the anterior-lateral portion of the vocal process, 2 cm from the surface of the vocal fold mucosa. The authors have described an ablation from a depth of 20 to 11 mm to protect the vocal fold mucosa and that it was carried out five times during the procedure¹⁹.

Other medical treatments

In addition to the surgeries described, treatments with injection of lidocaine, homeopathy, and speech therapy were published.

Injection of lidocaine

The authors described the injection of lidocaine 1% into the RLN in doses that varied from 2.5 to 5 ml. For this a syringe and 27 gauge needle was used to penetrate the neck to the right along the tracheoesophageal groove, below the cricothyroid articulation in the region of the RLN entry point into the larynx²⁰. After injection, laryngoscopy was performed on all subjects to confirm vocal fold paralysis on the right.

Homeopathy

The literature reported on the use of Argentum nitricum²¹ in the treatment of SD.

Speech Therapy

Although the articles comment that speech therapy is a possible treatment for SD, there are no reports in these articles on the strategies used in speech therapy sessions.

After a brief exposition of the information on the treatment proposed for SD, the following are the results of the literature reviewed, classified by type of treatment, presented in tables that include: the year of publication, the author(s) involved, the objective(s) of the study, and the results.

Table 1 shows the articles found in the bibliographic survey with the proposed treatment of BT injection.

Table 1 - Articles on the use of botulinum toxin (BT) injection for the treatment of spasmodic dysphonia

Table 2 presents the articles that include surgical procedures for the treatment of SD.

Table 2 - Articles with surgical procedures for treatment of spasmodic dysphonia divided by year, author (s), objective (s) and results

Table 3 presents the articles categorized as other medical treatments for SD.

Table 3 - Articles categorized as other treatments for spasmodic dysphonia divided by year, author (s), objective (s) and results

Table 4 presents articles that contemplate speech therapy in the treatment for SD.

Table 4 - Articles categorized as speech pathology (speech therapy) treatment for spasmodic dysphonia divided by year, author (s), objective (s), and results

Table 5 presents the articles that contemplate studies of literary review in the treatment of SD.

Table 5 - Articles categorized as literature review of spasmodic dysphonia treatments divided by year, author(s), objective(s), and results

The literature review on the proposed topic showed that in the last five years the medical treatments and speech therapy described in the literature were: BT injection, myectomy, neurectomy, selective laryngeal adductor denervation and reinervation, thyroplasty, radiofrequency thyroarytenoid myothermy, lidocaine injection, homeopathy and speech therapy.

Among the articles found, 37% reported medical treatment with BT injection and results indicated an improvement in the vocal quality analyzed by means of vocal and quality of life self-evaluation protocols. However, the observed results demonstrated the temporary effectiveness of the treatment and the need to reapply the toxin^22-32

The articles that reported on surgical procedures (33%) were based on the premise that surgery would be a long-lasting treatment option for SD, without the need to return to control pathology symptoms.

Among the surgical procedures, myectomy alone or combined with neurectomy was presented as an option in cases in which the patient desires a long-lasting outcome. The results presented were positive in most cases and the scholars stressed the irreversibility of the surgery^12-14,33.

Regarding selective laryngeal adductor denervation and reinnervation surgery, two articles from the same group of researchers were found. While one of these articles addressed a literature review³⁶, the other reported on the satisfactory outcome of the surgical procedure from the vocal analysis done by the voice handicap index protocol¹⁵.

In relation to thyroplasty, the results of this treatment were analyzed in more than one article showing the concern of a surgical team in improving the surgical procedures initially proposed. In general, the researchers discussed the indication and contra-indication of this surgery, presented modifications to the surgical technique, and pointed to the patient's own satisfaction in his/her voice quality^16-18.

The use of the Remacle modified radiofrequency thyroarytenoid myothermy was reported on in one study. The result was described as a good alternative to treat SD, though not considered effective in all cases since 50% of the patients had BT injection one year following myothermy¹⁹.

There was only one single study that used lidocaine injection (lidocaine block of the RLN) in the AdSD in order to investigate the effects on phonation. The results showed that blockage is possible, however the study did not present length of effect. The authors pointed out that this procedure may be used as a differential diagnostic resource for SD²⁰.

Homeopathy treatment was found in only one article which aimed to describe the perceptual and physiological changes in the vocal function of patients treated with classic homeopathy. The results found in this study showed that after three months of treatment, a significant reduction in the strained-strangled severity and quality of the voice was observed. The number of voice breaks was reduced and the patients demonstrated greater control of the speech mechanism, as well as a reported emotional well-being. For the authors, this may be a possible treatment for those patients who do not wish to use botox²¹.

Regarding speech pathology treatment, no articles that discussed the effects of vocal technique action in the treatment of SD during the period studied were found. Only one article commented on achieving positive results with speech therapy associated with BT injection in patients with good results in the Health Locus of Control "internal control" index (evaluation protocol of the patient's locus of control in his/her health)³⁵. Another literature review article pointed to two studies that discussed speech therapy as a treatment for SD. One of these studies reported that speech therapy improved speech intelligibility, voice functionality, confidence of the patient, when the therapy was combined with BT injection. In the other study, it was concluded that speech therapy, as well as pyschotherapy and biofeedback did not bring positive effect in controlling pathological symptoms⁴⁰.

In this survey, there were six literature review articles and half of them attempted to learn about treatment options published in a given period of time, whose scientific methodology could prove the effectiveness of treatments ^4,38,40. The others also tried to obtain the knowledge of proposed treatment of SD by only considering the results of surgery or the use of BT^36,37,39.

A single literature review identified the need for further studies in the understanding of neurological functioning in SD, for then it would be possible to attempt a treatment without side effects³⁹.

CONCLUSION

This study presents a bibliographic review on the proposed medical treatment and speech pathology for SD in the period between the years 2006 and 2010. The reported medical treatments included BT injection, surgical procedures, lidocaine injection and homeopathy. The use of BT injection showed results that indicated the satisfaction of the patients treated, although some of the articles point out the disadvantage of this treatment, i.e. the need to reapply BT after a few months. With regard to surgical procedures, they may be considered long-lasting and suitable for patients that do not wish to undergo BT injections. The studies, however, presented contingency of restricted patients and the results were based on the patient's own judgement as to his/her vocal quality. The use of lidocaine and homeopathy showed positive results in relation to the vocal quality of the patient and was suggested as an option for those patients who would not like to submit to surgery or BT injection. The few studies that did contemplate speech therapy showed positive results from this treatment when combined with BT injection. However, it is clear the lack of evidence on the effects of speech therapy in treating SD, although associated with medical treatment. Thus, there is the need for further research involving speech therapy in SD in associated with clinical and/or surgical treatment.

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Medical treatment and speech therapy for spasmodic dysphonia: a literature review

Eliana Maria Gradim Fabron^I; Viviane Cristina de Castro Marino^II; Talyssa de Carvalho Nóbile^III; Luciana Tavares Sebastião^IV; Suely Mayumi Motonaga Onofri^V

Publication Dates

• Publication in this collection
  21 June 2013
• Date of issue
  June 2013

History

• Received
  29 Sept 2011
• Accepted
  08 May 2012