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.     

Identification of symptoms for spasmodic dysphonia and vocal tremor: a comparison of expert and nonexpert judges

Spasmodic dysphonia is a rare voice disorder that is most successfully treated by injection of botulinum toxin (i.e., BOTOX) into the affected laryngeal muscles. BOTOX is currently available for use by professionals outside of metropolitan voice centers who may be unfamiliar with this rare disorder. Patients may seek assessment and treatment locally from clinicians who are unfamiliar with the speech symptoms for adductor-type (ADSD) or abductor-type (ABSD) spasmodic dysphonia. Although these disorders have been described in the literature, the symptoms have not been well defined and may appear similar to those of vocal tremor or muscle tension dysphonia (MTD). Thus, patients with spasmodic dysphonia might not be easily identified by local clinicians for treatment. The purpose of the current study was to determine whether voice clinicians with infrequent exposure to patients with spasmodic dysphonia could learn to identify speech symptoms for ADSD and ABSD comparable to voice clinicians with extensive experience with these disorders. The ratings of five nonexpert judges were compared to the ratings obtained from three expert judges. The results of this study demonstrated that nonexpert judges could be trained to identify the speech symptoms associated with ADSD, ABSD, and vocal tremor. While the nonexpert judges tended towards false positive judgements for the speech symptoms of interest, the overall speech symptom profiles for each type of voice disorder appeared comparable to those obtained from the expert judges. The symptom identificationscales used, therefore, have potential for use by clinicians unfamiliar with these disorders for correctly identifying persons with symptoms of ADSD and ABSD. Educational objectives: Readers will be able to (1) define the predominant speech symptoms reflective of the voice disorder categories of ABSD, ADSD, and vocal tremor; and (2) describe the methods utilized in a new perceptual training protocol for teaching clinicians how to identify predominant speech symptoms associated with the voice disorder categories of ABSD, ADSD, and vocal tremor.     

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     

Laryngeal Muscle Activity During Speech Breaks in Adductor Spasmodic Dysphonia

To determine the laryngeal muscle activation abnormalities that are associated with speech symptoms in adductor spasmodic dysphonia (ADSD), electromyographic measures of extrinsic and intrinsic laryngeal muscles during speech compared 1) muscle activity when ADSD patients had breaks in words with when they produced the same words without breaks; and 2) muscle activity in ADSD patients during speech without voice breaks with normal controls producing phonetically similar words. Simultaneous electromyographic recordings were made from the thyroarytenoid (TA), cricothyroid (CT), sternothyroid (ST), thyrohyoid(TH) and the posterior cricoarytenoid (PCA) muscles during speech testing in 11 ADSD patients and 10 control subjects. Speech breaks were identified and mean muscle activity measured starting 100 ms preceding a voice break and for the remainder of the word. Mean muscle activity level was significantly greater on break than non break words in ADSD patients only for the thyroarytenoid muscle(p<.001). No significant differences were found between the ADSD and control subjects during non break words for any of the laryngeal muscles studied. The results demonstrated that 1) only the thyroarytenoid, of the muscles tested, was affected in ADSD, 2) that muscle activation abnormalities were spasmodic, only appearing when symptoms occurred and 3) no imbalances of muscle tone were evident when speech disruptions did not appear.     

Diagnostic and therapeutic difficulties in laryngeal dystonia

Spasmodic dysphonia is a focal laryngeal dystonia. It presents as: adductor spasmodic dysphonia with the strain-strangle voice; abductor spasmodic dysphonia with whispering voice and breathy breaks in connected speech; and adductor respiratory dystonia with paradoxical vocal fold movements and stridor. It is most commonly treated by the intramuscular injection of botulinum toxin. In this article, the authors discuss difficulties in making diagnosis and treatment in patients with laryngeal dystonia concerning their own cases.     

Laryngeal electromyographic activity in adductor and abductor spasmodic dysphonia

Vocal symptoms in spasmodic dysphonia (SD) range from strain-strangle phonation and glottal-stop phonatory breaks of adductor SD to breathy phonation and aspirate phonatory breaks of abductor SD. Many SD subjects show both symptom types. Heterogeneity in vocal symptoms contributes to controversy surrounding the etiology(s) of SD. Acoustic/perceptual analyses of vocal symptoms are inconclusive in resolving this controversy. This investigation moves the search for distinguishing features of adductor and abductor SD to the level of neuromuscular control and analysis of intrinsic laryngeal muscle (adductor and abductor) activity. Subjects rated perceptually as primarily adductor or abductor SD sustained production of vegetative gestures and isolated speech sounds (/i/ and /s/). Qualitative and quantitative analyses of electromyographic signals recorded from thyroarytenoid (TA) failed to differentiate SD subjects by symptom type. Analysis of TA and posterior cricoarytenoid (PCA) activity in one abductor SD revealed high levels in both muscles during production of the voiced vowel. Data suggest that a possible explanation for symptom heterogeneity in SD is the relation between disrupted neuromotor input to laryngeal muscles and reflexive or conscious compensations constrained by laryngeal biomechanics.     

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.     

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。     

痉挛性发音障碍与声带麻痹的关系

目的探索痉挛性发音障碍（ｓｐａｓｍｏｄｉｃｄｙｓｐｈｏｎｉａ）与声带麻痹发病关系。方法用肌电图仪测定喉内肌电位，用电视闪光放大喉镜录像观察声带运动状态，将声带麻痹程度分为轻、中、重三度。结果１９８３～１９９４年１２年中遇到轻、中、重声带麻痹１３００例，在１３００例中伴有痉挛性发音障碍者５例；其中重度和中度声带麻痹者各１例，轻度者３例。结论通过５例的观察，发现声带麻痹的进行或治愈过程中皆可出现痉挛性发音障碍，考虑此５例为喉周围神经器质性病变所引起。     

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.     

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.     

痉挛性发音障碍与声带麻痹的关系

目的 探索痉挛性发音障碍与声带麻痹发病关系。方法 用肌电图仪测定喉内肌电位，用电视闪光放大喉镜录像观察声带运动状态，将声带麻痹程度分为轻、中、重三度。结果１９８３￣１９９４年１２月中遇到轻、中、重声带麻醉１３００例，在１３００例中伴有痉挛性发音障碍者５例；其中重度和中度声带麻痹者各１例，轻度者３例。结论 通过５例的观察，发现声带麻痹的进行或治愈过程中皆可出现痉挛性发音障碍，考虑此５例为喉周围神经器     

The prevalence of major psychiatric pathologies in patients with voice disorders

We conducted a study of 47 patients with various voice disorders to determine the prevalence of concomitant psychopathology. The prevalence of psychiatric symptoms varied considerably among patients with the three most common voice disorders: 63.6% among patients with vocal fold paralysis, 29.4% among those with functional dysphonia, and 7.1% among those with spasmodic dysphonia. Levels of anxiety and depression correlated moderately with the severity of voice symptoms in patients with vocal fold paralysis, but not in those with functional or spasmodic dysphonia. Certain abnormal personality traits--including interpersonal sensitivity and distrust of others--were more common among patients with functional dysphonia. The low rate of psychopathology among patients with spasmodic dysphonia is consistent with rates reported in previous investigations. Our findings suggest that the prevalence of psychopathology in patients with voice disorders varies according to the specific voice diagnosis, as does the relationship between specific psychiatric and voice symptoms.     

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.     

Intrinsic laryngeal muscle activity in a spastic dysphonia patient

EMG activity from four intrinsic laryngeal muscles (thyroarytenoid, posterior cricoarytenoid, interarytenoid, and cricothyroid) was obtained from one female spastic dysphonia patient while she performed a variety of speech and nonspeech tasks. These tasks were performed before and during a period of temporary unilateral laryngeal muscle paralysis. In the nonparalyzed condition, adductory muscle activity showed intermittent sudden increases that coincided with momentary voice arrests. These muscle patterns and accompanying voice interruptions were not present either when speech was produced in falsetto register or at anytime during the paralysis condition. The data suggest that individuals with this type of spastic dysphonia have normal morphology of recurrent laryngeal nerves and intrinsic laryngeal muscles, which means that the triggering mechanism(s) for spastic dysphonia symptoms must be located at some point neurologically upstream from the larynx.     

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.     

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.     

Effects of botulinum toxin on pathophysiology in spasmodic dysphonia

To determine the mechanism of symptom relief with treatment by botulinum toxin injection in persons with adductor spasmodic dysphonia (ADSD), we evaluated the effects of unilateral thyroarytenoid muscle injections on both injected and noninjected muscles in 10 subjects with ADSD, using electromyography on both sides of the larynx before and after treatment. The subjects' speech symptoms were reduced (p = .005) 2 weeks following injection, when the electromyographic study occurred. Muscle activation levels and the numbers of spasmodic muscle bursts decreased significantly (p < or = .03) postinjection in both the injected and noninjected muscles. The reductions in laryngeal muscle bursts correlated with symptom reduction (r > or = .7) in all muscles. Reductions in laryngeal muscle bursts did not relate to either absolute or normalized levels of muscle activity before or after botulinum toxin injection. The results suggest that changes in the central pathophysiology are responsible for changes in speech symptoms following treatment.     

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.     

Alternating Unilateral Botulinum Toxin Type A (BOTOX®) Injections for Spasmodic Dysphonia

Injection of botulinum toxin type A (BOTOX^®) into both thyroarytenoid muscles is an accepted treatment for spasmodic dysphonia. The authors of this study identified patients who could not tolerate the interval of breathy voice that immediately follows bilateral injections. These patients were offered a protocol in which the injection side was alternated on subsequent treatments. Eighteen patients who received at least two bilateral injections and two unilateral injections were reviewed. Alternating unilateral injections yielded a shorter breathy interval by an average of 12.7 days (P=.0007) and a shorter duration of return of spasmodic symptoms by an average of 26.0 days (P=.0006). Compared with bilateral injections, alternating unilateral injections yielded an average(median) of 3.2 more days of strong voice per day of breathy voice (P=.001). However, unilateral injections had a shorter average interval of strong voice (27.4 days; P=.007), as well as a slightly higher failure rate (4.9% vs. 1.1%). The authors conclude that alternating unilateral botulinum toxin type A injections are useful in patients with spasmodic dysphonia who have difficulty with the breathy voice that follows bilateral injection.