Botulinum Toxin Therapy for Abductor Spasmodic Dysphonia

Botulinum toxin has been widely accepted as an effective therapy for controlling the symptoms of adductor spasmodic dysphonia (ADSD). Reported experience with botulinum treatment for abductor spasmodic dysphonia (ABSD) has been less impressive. Factors that may impair outcomes for ABSD include differences in the pathophysiology of ADSD and ABSD and limitation of maximal dose from airway restriction with posterior cricoarytenoid muscle (PCA) weakness. We report our experience with botulinum injection of the PCA with an asymmetric dose escalation protocol, based on clinical observations that in ABSD, abductor spasms are often stronger on one side, usually the left. The nondominant side was injected with 1.25 units. Dominant side dose began at 5 units, with step-wise increments of 5 units per week until one of three endpoints was reached: Elimination of breathy voice breaks, complete abductor paralysis of the dominant side, or airway compromise. Fourteen of 17 patients achieved good or fair voice, with dominant-side doses ranging from 10 to 25 units. Exercise intolerance limited PCA dose in two patients. One patient had persisting breathiness that improved with medialization thyroplasty. Asymmetric botulinum toxin injection into PCA muscles can suppress abductor spasm in patients with ABSD, but breathiness may persist, because of inadequate glottal closure.     

Immunologic Characterization of Spasmodic Dysphonia Patients Who Develop Resistance to Botulinum Toxin

The immune status of six spasmodic dysphonia patients who became resistant to botulinum toxin was compared to that of a series of patients who remained responsive. The two groups were similar in terms of age, sex, and cumulative dose of toxin. Five of the resistant patients had a significant titer of anti-botulinum toxin IgG antibodies, as determined by enzyme-linked immunosorbent assay (ELISA). These same five resistant patients had a circulating titer of anti-heavy chain antibodies, but only three of these patients had a circulating titer of anti-light chain antibodies, as determined by Western blotting. By contrast, none of the responsive patients had antibodies against the holotoxin or its two chains. Interestingly, two of the resistant patients also had a low circulating titer of anti-botulinum toxin IgA antibodies. None of the responsive patients was IgA-positive. The cumulative dose of botulinum toxin administered to resistant patients was lower than that customarily associated with emergence of immunity in dystonia patients.     

Unilateral Versus Bilateral Injections of Botulinum Toxin in Patients with Adductor Spasmodic Dysphonia

Both unilateral and bilateral thyroarytenoid muscle injections of Botox provide effective management of voice symptoms in patients with adductor spasmodic dysphonia; however, the preferred injection technique has not been established. In this study, 16 patients were treated with unilateral injections (72 injections total) and 33 patients were managed with bilateral injections (133 injections total). Individual assignments to injection type were based on treatment previously received and dose was adjusted according to the patient's previous treatment response. An optimal treatment included a benefit lasting 3 months or more with side effects lasting 2 weeks or less. Compared to patients receiving bilateral injections, those receiving unilateral injections more frequently noted a benefit of 3 months or more (p = 0.03), side effects of 2 weeks or less duration (p = 0.03), as well as both a 3-month benefit and a 2-week or less side effect (p = 0.0004). Injection type had no effect on optimal Botox dosing with repeat injections. Successive unilateral injections at the same dose were more likely (p = 0.012) than successive bilateral injections to produce the same or longer duration of benefit. We conclude that a unilateral injection routine has a more optimal and consistent treatment effect/side effect profile.     

The Effect of Botulinum Toxin A on the Vocal Symptoms of Spastic Dysarthria: A Case Study

The vocal symptoms of spastic dysarthria and spasmodic dysphonia have many similar features. Botulinum toxin has been used effectively to treat spasmodic dysphonia. This study was designed to determine what vocal changes occur in an individual with spastic dysarthria following Botulinum toxin A injection into the thyroarytenoid muscles. Measures were obtained preinjection and three times postinjection. Acoustic and aerodynamic results were comparable to those reported for individuals with spasmodic dysphonia. The most marked change was increased DC airflow. Despite persistent breathiness, the participant reported great satisfaction with the result, particularly because of her more appropriate loudness. In addition, everyday listeners perceived significantly less listener burden and more relaxed and pleasant vocal quality postinjection.     

Botulinum toxin

The National Institutes of Health Consensus Development Conference on Clinical Use of Botulinum Toxin brought together neurologists, ophthalmologists, otolaryngologists, speech pathologists, and other health care professionals as well as the public to address the mechanisms of action of botulinum toxin, the indications and contraindications for botulinum toxin treatment, the general principles of technique of injection and handling for its safe and effective use, and the short-term and long-term side effects and complications of therapy. Following 2 days of presentations by experts and discussion by the audience, a consensus panel weighed the evidence and prepared their consensus statement. Among their findings, the panel recommended that (a) botulinum toxin therapy is safe and effective for treating strabismus, blepharospasm, hemifacial spasm, adductor spasmodic dysphonia, jaw-closing oromandibular dystonia, and cervical dystonia; (b) botulinum toxin is not curative in chronic neurological disorders; (c) the safety of botulinum toxin therapy during pregnancy, breast feeding, and chronic use during childhood is unknown; (d) the long-term effects of chronic treatment with botulinum toxin remain unknown; and (e) botulinum toxin should be administered by committed interdisciplinary teams of physicians and related health care professionals with appropriate instrumentation. The full text of the consensus panel's statement follows.     

Longitudinal Effects of Botulinum Toxin Injections on Voice-Related Quality of Life (V-RQOL) for Patients with Adductory Spasmodic Dysphonia

Adductory spasmodic dysphonia is a focal dystonia of laryngeal muscles. Patients with this disorder typically have severe vocal difficulties, with significant functional, social, and emotional consequences. There is no widely accepted cure for this condition, however, botulinum toxin injections of the thyroarytenoid muscles are considered by most voice clinicians to be the state of the art treatment. Based on extensive experience treating patients for adductory spasmodic dysphonia, we feel that traditional means of voice assessment do not adequately measure either the disease severity or the treatment outcomes. That is, listening to or acoustically analyzing limited phonatory samples does not capture the functional, social, and emotional consequences of this disorder. These consequences will be reflected in a patient's voice-related quality of life (V-RQOL). Using a validated voice outcomes instrument, the V-RQOL Measure, the purpose of this study was to quantify longitudinal changes in the V-RQOL of patients with adductory spasmodic dysphonia who are undergoing botulinum toxin injections. Twenty-seven consecutive new patients presenting with dysphonia to our institution during an 18-month period were diagnosed with adductory spasmodic dysphonia, and treated patients were evaluated prospectively using the V-RQOL Measure. Results indicated that (1) V-RQOL was initially very low for these patients, (2) botulinum toxin injections improved it significantly for each injection cycle studied, and (3) the magnitude of the treatment effect appears to change across injections.     

Treatment of spasmodic dysphonia (laryngeal dystonia) with local injections of Botulinum toxin

In 1984 the authors performed the first laryngeal injection of Botulinum toxin for laryngeal dystonia via percutaneous, electromyographically guided technique. Since that time we have treated 450 patients with adductor spasmodic dysphonia, abductor spasmodic dysphonia, and adductor breathing dystonia. In general, the adductor patients received bilateral injections of 1.25 U to 3.75 U, obtaining greater than 90% of normal voice. The abductor patients received unilateral or staged bilateral injections of the posterior cricoarytenoid muscles with 0.6 to 3.75 U, obtaining 70% of normal function. We have found laryngeal injections of Botulinum toxin to be safe and effective therapy for the symptoms of laryngeal dystonia (spasmodic dysphonia).     

Technique of percutaneous EMG-guided botulinum toxin injection of the larynx for spasmodic dystonia

Percutaneous electromyography (EMG)-guided technique of botulinum toxin (BT) injection of the larynx evolved from similar techniques for extraocular muscle injection in strabismus, as well as from experience with diagnostic laryngeal EMG. This technique permits rapid accurate injection of BT into the laryngeal muscles. Although usually injected into the thyroarytenoid muscle, BT can also be directed to the posterior cricoarytenoid and cricothyroid muscles. Complications are minimal and of short duration.     

Spasmodic dysphonia symptoms as initial presentation of amyotrophic lateral sclerosis

A patient initially diagnosed with adductor-type spasmodic dysphonia was referred for botulinum toxin (Botox) injections, but found on subsequent evaluation to have amyotrophic lateral sclerosis, and therefore Botox was not administered. This unique case underscores the need to delay botulinum toxin treatments in any patient with recent onset symptoms, and to obtain thorough motor speech and voice, otolaryngologic, and neurologic evaluation in all patients prior to consideration for injection.     

Botulinum toxin treatment of spasmodic dysphonia: Techniques, indications, efficacy

A group of 58 patients with spasmodic dysphonia (SD) was treated perorally or transcutaneously with botulinum toxin (BT), and followed for at least 6 months. Most were treated by peroral injection using indirect laryngoscopy to facilitate precise placement. An effort was made to disperse the toxin over the entire thyroarytenoid muscle in order to affect the greatest number of motor end-plates using the smallest possible effective dose. Severely symptomatic patients with primarily adductor SD had the best results. A potentiation effect is suggested by analysis of a subpopulation of patients, mostly injected unilaterally, for whom the outcome was more favorable for those who had had prior injections. One-month postinjection studies reflect significant improvement in measured readings of a standard passage, and this is consistent with the subjective and perceptual improvements noted. There were no severe complications. Peroral injection seems inadvisable for patients with mixed or abductor SD as well as for those with an uncontrollable gag reflex.     

Voice Handicap Index Results for Older Patients with Adductor Spasmodic Dysphonia

Adductor spasmodic dysphonia (ADSD) adversely affects a speaker's ability to effectively communicate. For many individuals suffering with ADSD, botulinum toxin (Botox) is the chosen treatment to remediate the symptoms. Although Botox's effects on symptom remediation have been examined before, patient perception of improvement post-Botox has been examined less frequently. Further, no studies have addressed the symptomatic changes in older adults that occur after Botox treatment. The Voice Handicap Index (VHI) was used as the instrument to assess older patient's (>65 years) perception of how ADSD impacts certain areas of their life pre- and post-Botox injection. The outcome of the VHI was related to a clinical judgment of voice severity. Participants also completed the Social Readjustment Rating Scale (SRRS) to examine overall stress level, and the outcome of the SRRS was correlated to postinjection VHI scores. Results indicated no significant correlation between VHI scores and voice severity or SRRS ratings. The current study suggests further study of voice outcomes with older adults with ADSD is needed.     

The Psychosocial Consequences of BOTOX Injections for Spasmodic Dysphonia: A Qualitative Study of Patients'' Experiences

OBJECTIVES/HYPOTHESIS: The purpose of this study is to examine the psychosocial consequences of BOTOX (Allergan, Inc. Irvine, CA) treatment for spasmodic dysphonia (SD). This article also explores how patients judge the success of treatment and make decisions about future treatment based on psychosocial issues relevant to them. STUDY DESIGN: This study follows the phenomenological tradition of qualitative inquiry in which the objective is to explore the lived experiences of a group of persons who share a common phenomenon, in this case receiving BOTOX injections for SD. METHODS: Six adults with SD who had been receiving BOTOX injections on a long-term basis participated in face-to-face interviews. The interviews were recorded, transcribed, and analyzed according to phenomenological guidelines to identify consistent themes as well as differences among participants' experiences. RESULTS: The results are summarized in three primary themes that suggest (1) participants' experiences vary over time based on changes in factors such as lifestyle and personal priorities; (2) BOTOX has multidimensional psychosocial implications in physical, personal, and social domains; and (3) participants individualize their treatment regimens, taking into consideration the burden of treatment, scheduling priorities, and other strategies to maximize the benefits of BOTOX. CONCLUSIONS: Based on this study, suggestions are provided for future research into a psychosocial outcome measurement, including longitudinal evaluations that accommodate changing patient priorities over time; multidimensional evaluations that incorporate physical, personal, and social issues; evaluations that include a measure of the burden of treatment; and evaluations that support a shared decision-making model with the voice clinicians.