Botulinum toxin for the treatment of spasmodic dysphonia

Spasmodic dysphonia is a focal laryngeal dystonia. Laryngeal dystonia presents as: adductor spasmodic dysphonia with the characteristic strain-strangle voice; abductor spasmodic dysphonia with hypophonia and breathy breaks in connected speech; and adductor respiratory dystonia with paradoxical vocal fold motion and intermittent stridor. Current treatment with periodic laryngeal intramuscular injections of botulinum toxin A has allowed patients to function more normally. In this article, the authors' treatment paradigm and experience in treating over 900 patients with laryngeal dystonia are discussed.     

Findings of multiple muscle involvement in a study of 214 patients with laryngeal dystonia using fine-wire electromyography

Although perceptual and stroboscopic data help in diagnosing and classifying laryngeal dystonia, these measures do not aid the voice clinician in targeting which specific muscles to treat with botulinum toxin. Most patients achieve smoother, less effortful voicing with standard injection regimens. However, there is a notable failure rate. We performed fine-wire electromyography on 214 consecutive patients with laryngeal dystonia. We correlated voice ratings, stroboscopy data, and fine-wire electromyography data. Videostroboscopy was successful in visually demonstrating most of the audible findings in isolated vocal tremor, but it was much less successful in identifying breaks alone or a combination of breaks and tremor. Fine-wire electromyography revealed that the thyroarytenoid muscle was significantly more likely than the lateral cricoarytenoid muscle to be the predominant muscle associated with adductor spasmodic dysphonia, and that the thyroarytenoid and lateral cricoarytenoid muscles were equally likely to be predominantly involved in tremor spasmodic dysphonia. In addition, several patients in both the adductor spasmodic dysphonia and the tremor spasmodic dysphonia groups presented with interarytenoid muscle predominance. All of the intrinsic laryngeal muscles are capable of being the predominant muscle in laryngeal dystonia, and there are patterns of muscle abnormalities that differ between adductor spasmodic dysphonia and tremor spasmodic dysphonia. Some of the failures in treating adductor spasmodic dysphonia with botulinum toxin, and the greater difficulty with success in treating patients with tremor spasmodic dysphonia, are due to failure to deliver toxin to the appropriate muscles.     

Listening: the key to diagnosing spasmodic dysphonia

Spasmodic dysphonia (SD) is a focal dystonia of the larynx. Adductor spasmodic dysphonia (ADSD) involves the laryngeal adductor muscles, and symptoms of vocal roughness, staccato-like sounds, and stops in phonation. Abductor spasmodic dysphonia (ABSD) affects the laryngeal abductor muscles, resulting in a breathy or whispered voice quality and voice breaks. SD has a significant impact on the quality of life. This article discusses symptoms of SD and the standard treatment of SD.     

Singer's dystonia: first report of a variant of spasmodic dysphonia

OBJECTIVES: We discuss the phonatory characteristics of a previously undescribed focal laryngeal dystonia present in the singing voice. METHODS: We performed a retrospective chart review of 5 patients with singer's dystonia at a neurolaryngology referral center. RESULTS: Four patients reviewed demonstrated phonatory characteristics consistent with adductor spasmodic dysphonia present in their singing voice. One patient demonstrated abductor spasmodic dysphonia in the singing voice. Each patient initially exhibited normal connected speech in conversational voicing. The treatment protocol and outcome are discussed, including the use of botulinum toxin. CONCLUSIONS: Singer's dystonia is a previously undescribed neurologic disorder that should be understood by those who treat voice performers and voice disorders.     

Botulinum toxin management of spasmodic dysphonia (laryngeal dystonia): A 12-year experience in more than 900 patients

Objectives: This paper reviews a 12-year experience in more than 900 patients with spasmodic dysphonia who have been treated with botulinum toxin. Study Design: This is a retrospective analysis of patients with adductor spasmodic dysphonia (strainstrangled voice), abductor spasmodic dysphonia (whispering voice), and adductor breathing dystonia (paradoxical vocal fold motion), all of whom have been treated with botulinum toxin injections for relief of symptom. Methods: All of the patients were studied with a complete head and neck and neurologic examination; fiberoptic laryngostroboscopy; acoustic and aerodynamic measures; and a speech evaluation including the Universal spasmodic dysphonia rating scale. Some were given electromyography. All patients received botulinum toxin injections into the affected muscles under electromyographic guidance. Results: The adductor patients had an average benefit of 90% of normal function lasting an average of 15.1 weeks. The abductor patients had an average benefit of 66.7% of normal function lasting an average of 10.5 weeks. Adverse effects included mild breathiness and coughing on fluids in the adductor patients, and mild stridor in a few of the abductor patients. Conclusion: Botulinum toxin A injection of the laryngeal hyperfunctional muscles has been found over the past 12 years to be the treatment of choice to control the dystonic symptoms in most patients with spasmodic dysphonia. Laryngoscope, 108:1435–1441, 1998     

Botulinum toxin management of adductor spasmodic dysphonia after failed recurrent laryngeal nerve section

This study examined botulinum toxin type A (BTX-A) treatment of adductor spasmodic dysphonia patients who had previously undergone recurrent laryngeal nerve section that failed to control symptoms. Information was retrieved from records of patients treated by our group between 1984 and 1999. Complete records with standardized outcome measurements were available for 181 BTX-A injection sessions in 16 patients who had had nerve section. These were compared to previously published information regarding 4,621 sessions in 639 adductor spasmodic dysphonia patients also treated by our group. Treatment with BTX-A resulted in significant improvement in voice function in the studied patients (change, 38.2% +/- 24.5%; p < .0001). The onset of effect took place approximately 2.3 days after treatment, and the peak effect about 10.0 days after treatment. The therapeutic effect lasted 14.1 weeks on the average. These features were not significantly different from those observed in adductor spasmodic dysphonia patients as a whole. The incidence of complications was also comparable. However, lower baseline and peak posttreatment perceptions of voice function in the nerve section group were statistically significant (baseline, 45.6% +/- 23.0% versus 52.4% +/- 22.0%; peak, 83.8% +/- 16.4% versus 89.7% +/- 13.0%; both p < .001). We conclude that BTX-A is effective in the treatment of adductor spasmodic dysphonia in patients who have had recurrent nerve section. However, nerve section may adversely affect perceived voice function and may make botulinum toxin therapy less satisfactory. Because of this finding, and because of the unusual pathological features of the focal dystonias, irreversible means of treating adductor spasmodic dysphonia should be approached with caution.     

内收型痉挛性发音障碍的语音特征

目的 探讨内收型痉挛性发音障碍的语音特征.方法 采用嗓音和语音的声信号和三维语图分析及主观评价的方法对1O例内收型痉挛性发音障碍患者(女7例,男3例)的语音特征与10例健康志愿者(男5例,女5例)进行对比.结果 内收型痉挛性发音障碍主要表现为音质、音韵及语音的流畅性改变,在朗读文章时出现紧张性发音困难,语音颤抖,频率及响度瞬间起伏,嗓音挤卡、中断,语音延长,失去正常韵律.10例患者中表现为轻度障碍者(异常音节数<25%)1例,中度障碍(异常音节数占25%～49%)6例,重度(异常音节数占50%～74%)1例,极重度(异常音节数≥75%)2例.10例患者朗读时间中位数为49 S,声信号中间断出现无音区,无音比率中位数为42%;而健康对照组朗读时间中位数为30 S,无声音中断.在三维语图中不同的患者在各自症状音节中可以看到嗓音起始时间延长,元音共振峰不规则、断裂甚至消失,症状音节的辅音缺失,或塞擦音的擦音成分延长等.结论 内收型痉挛性发音障碍语音特征为音质、音韵及语音的流畅性改变,在症状音节的三维语图中可以看到相应的元音或辅音音素的特征性改变.     

Effects of Botulinum Toxin Type A Injections on Aerodynamic Measures of Spasmodic Dysphonia

The effects of botulinum toxin type A (BOTOX^®) injections on aerodynamic measures of phonation were examined in 30 patients with adductor spasmodic dysphonia. Patients received bilateral injections of 2.5 U of botulinum toxin type A in each thyroarytenoid muscle. Measures of air pressure, average airflow, coefficient of variation (CV) of airflow, and laryngeal resistance were obtained before the injections and at 2 and 10 weeks after the injections. These measures were also obtained from 12 normal subjects. Compared with normal subjects, the spasmodic dysphonia patients had significantly higher preinjection values for air pressure, CV of airflow, and laryngeal resistance. At 2 and 10 weeks after the botulinum toxin type A injections, the spasmodic dysphonia patients showed a significant increase in the average airflow values and a significant decrease in the CV of airflow values and the laryngeal resistance values. At 10 weeks after the injections, the values for the three measures began to approach the preinjection values. It is concluded that these aerodynamic measures of phonation can provide useful measures of treatment outcome in adductor spasmodic dysphonia.     

Laryngeal long latency response conditioning in abductor spasmodic dysphonia.

Previously, we demonstrated that patients with adductor spasmodic dysphonia (ADSD) have a disinhibition of laryngeal responses to sensory input. In this study, sensorimotor responses to stimulation of the superior laryngeal nerve were compared between 10 subjects with abductor spasmodic dysphonia (ABSD) and 15 normal volunteers. The groups had similar latency and frequency characteristics of their unconditioned adductor responses (p>.05). The conditioned R1 (early) responses of the subjects with ABSD were greater and more variable in amplitude than those of the normal volunteers (p< or =.008). Similar R2 (late) conditioning effects were found in both groups, with a nonsignificant trend toward reduced inhibition of contralateral R2 responses at lower interstimulus intervals (p = .01) in the patient group. Thus, inhibitory mechanisms that modulate the R1 laryngeal sensorimotor pathway in the brain stem may be abnormal in subjects with ABSD. Abnormal modulation of laryngeal sensorimotor responses seems present in both types of spasmodic dysphonia.     

Laryngeal dystonia: a series with botulinum toxin therapy

Laryngeal dystonia is a syndrome characterized by action-induced, involuntary spasms of the laryngeal muscles. Most patients have involvement of the adductor laryngeal muscles producing uncontrolled spasms during phonation, and a "strain-strangle" speech pattern commonly termed "spastic dysphonia." Other patients have involvement of the abductor muscles producing "whispering dysphonia." Rare patients have paradoxical vocal cord motion during respiration with adductor spasms on inspiration. Over the past 5 years we have used botulinum toxin (BOTOX) to treat more than 200 patients with laryngeal dystonia. This group includes patients with adductor involvement (phonatory dystonia, recurrent laryngeal nerve section failure, respiratory dystonia) and those with abductor involvement (whispering dystonia). Patients received benefit within 24 to 72 hours, with sustained improvement for 2 to 9 months with an average of 4 months. Patients improved to an average of 90% of normal function. Clinically significant adverse effects included extended breathy dysphonia and mild choking on fluids. BOTOX has become our treatment of choice for dystonic conditions of the larynx.     

Effects of botulinum toxin therapy in patients with adductor spasmodic dysphonia: acoustic, aerodynamic, and videoendoscopic findings.

Botulinum toxin has been previously reported to be successful in the treatment of spasmodic dysphonia. To objectively document results, 11 patients with adductor spasmodic dysphonia who received unilateral treatment of the thyroarytenoid muscle were studied. Acoustic analyses and airflow rates during sustained phonation and flexible videoendoscopy were performed prior to, 1 week and 1 month after injection. 1. Acoustic parameters demonstrated significant voice improvement, although abnormal characteristics remained. 2. Mean airflow rates were increased 1 week after injection with almost normal values 1 month later. 3. Videolaryngoscopy showed an effective reduction of intrinsic laryngeal muscle hyperfunction with less effect on extrinsic muscle activity. Interrelations between videolaryngoscopic rating scores, acoustic results and aerodynamic results are discussed.     

The Swallowing Side Effects of Botulinum Toxin Type A Injection in Spasmodic Dysphonia

Botulinum toxin type A (BOTOX®) injection of the thyroarytenoid muscle is used to control speech symptoms in patients with adductor spasmodic dysphonia. Transient difficulty in swallowing liquids is a common treatment side effect. Laryngeal movement durations were measured during swallowing in 13 adductor spasmodic dysphonia patients undergoing treatment and in 6 normal control subjects in order to determine the following: 1. whether, prior to the injection, laryngeal movement durations were longer in the spasmodic dysphonia patients than in the control subjects; 2. whether movement durations increased following the injections; 3. whether preinjection swallowing difficulties related to postinjection swallowing measurements and postinjection patient reports of swallowing problems. A piezoelectric movement transducer was shown to be accurate for noninvasive measurement of laryngeal movement duration in relation to muscle onset and offset for hyoid elevation and relaxation. Before botulinum toxin type A injection, no significant differences in swallowing duration were found between the patient and control groups. Four patients with swallowing complaints prior to injection had longer laryngeal movement durations than the other spasmodic dysphonia patients and the control subjects. Following injection, laryngeal movement durations increased in the patients with spasmodic dysphonia, and eight patients reported dysphagia for an average of 2 weeks. Relationships were found between the patients' initial reports of swallowing problems and increased laryngeal movement durations before and after botulinum toxin type A injection. Those patients initially reporting swallowing difficulties had severe dysphagia for 2 weeks after the injection. Patient reports of dysphagia prior to injection may indicate a greater likelihood of significant dysphagia following thyroarytenoid injection with botulinum toxin type A.     

Spasmodic laryngeal dyspnea: a rare manifestation of laryngeal dystonia

We describe clinical experiences in the management of three patients with laryngopharyngeal dystonia causing severe breathing problems. In contrast to spasmodic dysphonia, which presents with action-induced involuntary spasms of laryngeal muscles during speaking, all three patients showed laryngopharyngeal spasms primarily during respiration. In analogy to spasmodic dysphonia we propose the term spasmodic laryngeal dyspnea for this rare condition. Localized unilateral botulinum toxin injected into the thyroarytenoid muscle and /or ventricular folds reduced the quantity and quality of spasms and led to a pronounced improvement of breathing problems.     

Long-term follow-up results of selective laryngeal adductor denervation-reinnervation surgery for adductor spasmodic dysphonia

Selective laryngeal adductor denervation-reinnervation surgery for the treatment of adductor spasmodic dysphonia was reported in 1999 in 21 patients with encouraging results. Here, we report long-term results of this procedure. Surgical outcome was evaluated using patient surveys and perceptual voice assessment. Measured outcomes included Voice Handicap Index (VHI)-10 scores, patient questionnaire, and perceptual evaluation for voice breaks and breathiness. Patient survey was obtained from 83 patients, and perceptual voice evaluation was performed in voice samples from 46 patients. Average follow-up interval was 49 months. Mean VHI-10 scores improved from a mean of 35.6 to 12.7. Eighty-three percent showed significantly improved VHI-10 scores, representing improved physical, social, and emotional well-being. There was a high degree of patient satisfaction, with 91% agreeing that their voice is more fluent after the surgery. Perceptual evaluation of postoperative voice samples revealed voice breaks in 26% (15% mild, 4% moderate, 7% severe) and breathiness in 30% (11% mild, 13% moderate, 6% severe). A majority of patients had stable, long-lasting resolution of spasmodic voice breaks.     

Resistance to botulinum toxin injections for spasmodic dysphonia

A known complication of botulinum toxin injections in the treatment of dystonia has been the occasional development of resistance. This has been seen primarily with patients who receive injections for torticollis. We report on 2 patients who, after several years of receiving injections for spasmodic dysphonia, developed clinical resistance by failing to have expected voice improvement after receiving laryngeal reinjection. One of the 2 patients demonstrated antibodies to botulinum toxin by mouse neutralization bioassay. The second patient had negative bioassay results but had no clinical response to the test toxin injection of facial muscles. These cases demonstrate that, although uncommon, resistance to botulinum toxin injections can occur in the treatment of spasmodic dysphonia. We offer suggestions to limit this complication.     

Die Behandlung laryngealer Bewegungsstörungen mit Botulinumtoxinen

Laryngeal dystonia (spasmodic dysphonia) is a movement disorder characterised by involuntary contractions of the laryngeal muscles involved in vocalisation. The introduction of botulinum toxin (BTX) in the treatment of laryngeal dystonia had a major clinical impact due to the striking improvement of symptoms. Most patients with severe types of spasmodic dysphonia are treated with injections of botulinum toxin type A. For patients with a resistance against type A toxin there is a new hypercleaned type A toxin or type B available. Research on type F toxin is also underway. In this article, the history of botulinum toxin, its therapeutic activity and possibilities for its use are described.     

Contemporary management of spasmodic dysphonia

PURPOSE OF REVIEW: To review current concept in spasmodic dysphonia management. RECENT FINDINGS: The standard of care for spasmodic dysphonia in 2004 remains botulinum toxin chemodenervation for symptomatic management. This is supported by a large body of literature attesting to its efficacy in many different hands, particularly for the adductor form of the disorder. New surgical approaches await the crucial test of time, in view of historical difficulties in achieving long-term benefit via recurrent nerve section, and currently, surgery is best reserved for the rare patient who does not benefit or cannot tolerate botulinum toxin injections. Despite efforts to refine both surgical and botulinum toxin treatment, symptom relief in abductor spasmodic dysphonia and dystonia with tremor remains suboptimal. SUMMARY: Spasmodic dysphonia is a disorder of the central nervous system rather than the larynx, and as in other forms of dystonia, interventions at the end organ have not offered a definitive cure. The pathophysiology underlying dystonia is becoming better understood as a result of discoveries in genetically based forms of the disorder, and this approach is the most promising avenue to a long-term solution.     

Zur oromandibul?ren, pharyngealen und laryngealen Anwendung von Botulinumtoxin

Dystonias of the oral, pharyngeal and laryngeal muscles are potential causes of deglutitive, respiratory and communicative disorders. In addition to functional deficits such as dysphagia, dysarthria and dysphonia, social disadvantages may arise from the visible or audible manifestations. Treatment with botulinum toxin offers symptomatic and temporary therapeutic effects. Examples of applications in oromandibular dystonia, palatoclonus, dysphagia and laryngeal dystonia (e.g., spasmodic dysphonia) are described.     

痉挛性发音障碍的喉功能特点

目的 为了探讨痉挛性发音障碍的喉功能特点及其发音障碍的表现形式。方法 对24例痉挛性发音障碍患者（男4例,女18例）的发病诱因、发音障碍特征、喉镜所见、喉肌电及喉空气动力学改变进行了分析。结果 痉挛性发音障碍主要表现为音韵及声音的流畅性障碍,主观听觉上以紧张性发音障碍为特点;喉镜检查可看到痉挛性发音时声带过度内收,室带不同程度的内收超越,重者声带强烈内收,会厌、室带以及整个喉呈闭锁状态;典型的喉肌电图所见为束发性放电;喉呼气流率明显减少。结论 痉挛性发音障碍伴随着紧张性发音的同时声带或整个喉强烈内收痉挛,同时伴有呼气流率下降,典型病例可看到喉肌电的改变。     

Spasmodic dysphonia: An overview of clinical features and treatment options

Spasmodic dysphonia (SD) is considered a rare focal laryngeal dystonia characterized by task-specific voice dysfluency resulting from selective intrinsic laryngeal musculature hyperfunction. Symptoms may be attenuated by a sensory trick. Although SD can be seen at times in generalized dystonia syndrome, it is typically a sporadic phenomenon, and the involvement of the laryngeal adductor muscles is more common than that of the abductor muscles. This research reviews the literature for the pathogenesis, clinical characteristics, treatment options, and current management methods of SD. Technological advances have enabled clinicians to better understand the connection between laryngeal function and dysfunction. Refinements in imaging and genetic investigation techniques have helped better understand the underlying mechanisms of this neurolaryngology disorder. Currently, the standard of care for SD is the symptomatic management of botulinum toxin (BT) chemodenervation. This is supported by a large body of literature attesting to its efficacy in many different research studies, particularly in the uncomplicated adductor form of the disorder. Efforts towards surgical treatment predate the development of BT treatment by a decade, but the long-term efficacy has not been proven and, further research is expected. Symptom relief in patients with abductor SD and dystonia with tremors after surgical and BT treatments and those in patients remains suboptimal.