Spasmodic Dysphonia

Author Credentials 

Original author:
Gayle Woodson, MD
Professor and Chair
Department of Otolaryngology – Head & Neck Surgery
Southern Illinois University

Update by:
Lee M. Akst, MD
Director, Laryngology
Johns Hopkins Department of Otolaryngology – Head and Neck Surgery
601 N Caroline Street, 6th Floor
Baltimore, MD 21287

Module Summary

Spasmodic Dysphonia is a neurogenic voice disorder caused by involuntary laryngeal muscle contractions. The cause is unknown, and there is no cure. Symptoms can be reduced by using Botulinum toxin or surgery to weaken laryngeal muscles.

Module Learning Objectives 
  1. Recgonize the presenting symptoms and signs of spasmodic dysphonia (SD).
  2. Summarize the theories of the pathogenesis of SD.
  3. Explain the rationale for botulinum toxin therapy of SD.
  4. Cite the efficacy of current surgical procedures used to treat SD.

Anatomy

Learning Objectives 
  1. Understand that while the exact pathophysiology of spasmodic dysphonia has not been fully characterized, there is evidence that functional abnormalities within parts of the brain related to organization of speech (laryngeal/orofacial sensorimotor cortex, basal ganglia, ventral thalamus, and cerebellum) may relate to symptoms of SD.
References 
  1. Simonyan K, Ludlow CL. Abnormal structure-function relationship in spasmodic dysphonia. Cereb Cortex. 2012 Feb;22(2):417-25. 
  2. Bianchi S, Battistella G, Huddleston H, Scharf R, Fleysher L, Rumbach AF, Frucht SJ, Blitzer A, Ozelius LJ, Simonyan K. Phenotype- and genotype-specific structural alterations in spasmodic dysphonia. Mov Disord. 2017 Apr;32(4):560-568.
  3. Mor N, Simonyan K, Blitzer A. Central voice production and pathophysiology of spasmodic dysphonia. Laryngoscope. 2018 Jan;128(1):177-183.

Pathogenesis

Learning Objectives 
  1. Understand that for many years, Spasmodic Dysphonia (SD) was widely believed to be a psychogenic problem.
    1. This was because the symptoms are variable and exacerbated by stress.
  2. Know that SD is now considered to be a focal dystonia of the larynx.
  3. Know that a dystonia is a central defect in motor control that causes involuntary muscle contractions.
  4. Realize that the pathogenesis of dystonia is unknown.
  5. Know that secondary dystonias are often associated with lesions in the basal ganglia, but primary dystonias (such as SD) have not been associated with identifiable lesions.
  6. Know that dystonias may be focal or diffuse.
    1. Blepharospasm, torticollis, and writer’s cramp are focal dystonias.
    2. Meige’s syndrome is a regional dystonia of face and neck.
    3. A diffuse dystonia affects posture and ambulation.
  7. Know that SD is usually idiopathic, but may be familial.
  8. Understand that dystonia onset has been associated with a wide variety of causes, including genetic, stroke, trauma, or drugs.
    1. Recognize that many SD patients perceive their disorder to have had sudden onset with a specific precipitating event
  9. Know that SD is usually isolated, but may be associated with other dystonia.
  10. Recognize that the fundamental problem is involuntary spasms in laryngeal muscles.
    1. The most common presentation is adductor spasmodic dysphonia, with episodic or sustained contraction of adductor muscles.
    2. The larynx closes too tightly, so that excessive pressure is required for phonation.
    3. A brief spasm interrupts phonation (voice break) while a sustained spasm results in a strained and tight voice.
    4. Abductor spasmodic dysphonia (about 10 times less common) is manifested by involuntary contractions of abductor muscles, and/or suppression of contraction of adductor muscles. The result is a breathy voice.
  11. Know that an additional factor is the individual compensatory strategy used by each patient in coping with the involuntary muscle spasms.
  12. Know that patients may use a variety of approaches, such as whispering, altering pitch, speaking on inspiration, avoiding certain words, etc.
    1. Thus there is a great degree of variability in the speech of patients with spasmodic dysphonia.
References 
  1. Swenson M, Zwirner P, Murry T, Woodson GE. Medical Evaluation of Patients with Spasmodic Dysphonia. Journal of Voice, 6:320-324, 1992.
  2. Van Pelt F, Ludlow CL, Smith PJ. Comparison of muscle activation patterns in adductor and abductor spasmodic dysphonia. Ann Otol Rhinol Laryngol. 1994 Mar;103(3):192-200.
  3. Woodson GE: “Spasmodic Dysphonia.” In: Current Therapy in Otolaryngology, Head and Neck Surgery. Gates GE, ed.Mosby, 1998.
  4. Childs L, Rickert S, Murry T, Blitzer A, Sulica L. Patient perceptions of factors leading to spasmodic dysphonia: a combined clinical experience of 350 patients. Laryngoscope. 2011 Oct;121(10):2195-8.

Basic Science

Learning Objectives 
  1. Understand that phonation is the passive vibration of the vocal folds, powered by exhaled air.
  2. Know that normal phonation requires that the vocal folds be precisely approximated, i.e., lightly touching.
    1. If they are pressed tightly together, excess pressure is required, the patient notices increased effort, and the voice sounds strained.
    2. A sudden closing spasm in the middle of phonation will alter or interrupt the sound.
    3. Conversely, if the vocal folds are not positioned close enough together, air will escape without producing sound, and the voice will be breathy, or a whisper.
References 
  1. Cummings Otolaryngology Head and Neck Surgery, Elsevier/Mosby: Woodson: Laryngeal and Pharyngeal Function, Fourth Edition, Volume 3: 1963-1974, 2005.
  2. Ludlow CL. Spasmodic dysphonia: a laryngeal control disorder specific to speech. J Neurosci. 2011 Jan 19;31(3):793-7. Review.

Incidence

Learning Objectives 
  1. Know that SD is a rare disorder, occurring in roughly 1-4 people per 100,000 people.
  2. Know that the onset of symptoms is usually between the ages of 30 and 50.
  3. Realize that SD is more common in women than men.
  4. Understand that adductor SD is approximately 10 times more common than abductor SD.
References 
  1. NIDCD Fact Sheet Spasmodic Dysphonia. National Institutes of Health, National Institute on Deafness and Other Communication Disorders. Accessed on May 15, 2015. 

Genetics

Learning Objectives 
  1. Know that SD may occur in association with other dystonias, and may be familial.
  2. Some of the genes with disease-causing mutations that have been associated with spasmodic dysphonia are TOR1A (DYT1), TUBB4 (DYT4), and THAP1 (DYT6)
  3. Despite these associations, screening for gene mutations in affected patients seems to have low diagnostic yield in sporadic SD
References 
  1. de Gusmão CM, Fuchs T, Moses A, Multhaupt-Buell T, Song PC, Ozelius LJ, Franco RA, Sharma N. Dystonia-Causing Mutations as a Contribution to the Etiology of Spasmodic Dysphonia. Otolaryngol Head Neck Surg. 2016 Oct;155(4):624-8. 
  2. Lohmann K, Wilcox RA, Winkler S, Ramirez A, Rakovic A, Park JS, Arns B, Lohnau T, Groen J, Kasten M, Brüggemann N, Hagenah J, Schmidt A, Kaiser FJ, Kumar KR, Zschiedrich K, Alvarez-Fischer D, Altenmüller E, Ferbert A, Lang AE, Münchau A, Kostic V, Simonyan K, Agzarian M, Ozelius LJ, Langeveld AP, Sue CM, Tijssen MA, Klein C. Whispering dysphonia (DYT4 dystonia) is caused by a mutation in the TUBB4 gene. Ann Neurol. 2013 Apr;73(4):537-45. 

Patient Evaluation

Learning Objectives 
  1. Understand that expert consensus advocated a three-tiered approach to evaluation and diagnosis:
    1. History, with focused screening questions
    2. A speech examination
    3. Endoscopic evaluation of the larynx
  2. Know to ascertain the following patient history
    1. Voice is disrupted by episodic voice breaks or a continually strained and strangled voice
    2. Onset may be sudden or gradual.
    3. It does not hurt to talk.
    4. Spasms usually vary by task. For example, a patient may still have a normal falsetto or singing voice, and laughter may be unaffected. Telephone conversation is usually much worse than face-to-face conversation.
    5. Symptoms are worse under stress
    6. There may be associated dystonias, such as blepharospasm or writer’s cramp.
  3. Recognize that careful perceptual evaluation of the patient’s voice by a trained listener can lead to probable SD diagnosis
    1. The hallmark symptoms are strained, effortful voice with voice breaks
    2. Different sentences emphasize phonemes which require a more or less tightly adducted laryngeal posture during speech, and difference in voice quality between these types of tasks may indicate adductor vs abductor SD
      1. For adductor SD, voice breaks occur most commonly with vowels at the onset of words: “We eat eggs every day.”
      2. For abductor SD, voice breaks are most prominent in vowels after unvoiced consonants: “Pay Paul a penny.”
  4. Know to carefully examine the patient for the following:
    1. Larynx appears anatomically normal.
    2. There is often associated tremor of the palate and/or pharynx.
    3. Any neurological sign other than tremor or associated dystonia suggests another etiology than SD.
    4. Flexible endoscopy demonstrates spasmodic closure of the larynx in adductor SD, or abduction in abductor SD.
References 
  1. Chhetri DK, Merati AL, Blumin JH, Sulica L, Damrose EJ, Tsai VW. Reliability of the perceptual evaluation of adductor spasmodic dysphonia. Ann Otol Rhinol Laryngol. 2008 Mar;117(3):159-65. 
  2. Ludlow CL, Adler CH, Berke GS, Bielamowicz SA, Blitzer A, Bressman SB, Hallett M, Jinnah HA, Juergens U, Martin SB, Perlmutter JS, Sapienza C, Singleton A, Tanner CM, Woodson GE. Research priorities in spasmodic dysphonia. Otolaryngol Head Neck Surg. 2008 Oct;139(4):495-505. 
  3. Roy N. Differential diagnosis of muscle tension dysphonia and spasmodic dysphonia. Curr Opin Otolaryngol Head Neck Surg. 2010 Jun;18(3):165-70. 

Measurement of Functional Status

Learning Objectives 
  1. Understand that for patient satisfaction, the most important outcomes are the patient’s perception of his own communication and the effort involved in speaking. A diary is helpful for recording this information.
  2. Understand that for perceptual rating, trained listeners can rate the voice and speech according to standardized scales.
  3. Know that for acoustic analysis, the most constant abnormality is the occurrence of voice breaks during production of sustained vowels. A reduction in the number of voice breaks correlates very well with symptomatic improvement.
  4. Know that for airflow measurements may reveal reduced flow during production of a sustained vowel in adductor SD, and airflow measures can also track response to treatment
    1. Airflow increases to slightly above normal with successful injection of Botulinum toxin into laryngeal adductor muscles.
    2. Excessive botulinum toxin injection results in a breathy voice and much higher than normal airflow.
  5. Understand that in abductor SD, spikes of increased airflow correlate with abductor spasms.
  6. Know that laryngeal EMG is useful to confirm the site of injection for botulinum toxin, but is not considered necessary for diagnosis of SD
References 
  1. Zwirner P, Murry T,Swenson M, Woodson GE. Effects of Botulinum Toxin Therapy in Patients with Adductor Spasmodic Dysphonia: Acoustic, Aerodynamic and Videoendoscopic Findings. Laryngoscope. 102:400-406, 1992.
  2. Sapienza CM, Walton S, Murry T. Adductor spasmodic dysphonia and muscular tension dysphonia: acoustic analysis of sustained phonation and reading. J Voice. 2000 Dec;14(4):502-20.
  3. Van Pelt F, Ludlow CL, Smith PJ. Comparison of muscle activation patterns in adductor and abductor spasmodic dysphonia. Ann Otol Rhinol Laryngol. 1994 Mar;103(3):192-200.

Imaging

Learning Objectives 
  1. Know that flexible videolaryngoscopy is essential in evaluating patients who present with possible SD, to document the abnormal laryngeal movements, as well as compensatory vocal habits.
  2. Know that radiologic imaging is not indicated, unless the neurological evaluation indicates a focal lesion
References 
  1. Ludlow CL, Adler CH, Berke GS, Bielamowicz SA, Blitzer A, Bressman SB, Hallett M, Jinnah HA, Juergens U, Martin SB, Perlmutter JS, Sapienza C, Singleton A, Tanner CM, Woodson GE. Research priorities in spasmodic dysphonia. Otolaryngol Head Neck Surg. 2008 Oct;139(4):495-505.

Treatment

Learning Objectives 
  1. Know that botulinum toxin and surgery are the mainstays of treatment.

Medical Therapies

Learning Objectives 
  1. Know that currently, the treatment of choice for SD is botulinum toxin injection to the affected muscles.
  2. Minute quantities are injected directly into laryngeal muscles. This eliminates or decreases the strength of the spasms. However, it also decreases vocal power. Thus, the voice is not completely normal, but is much smoother and easier to produce.
  3. Either bilateral or unilateral injections can be used effectively. Usual dose for bilateral injections ranges from 1.25 to 2.5 units on each side.
  4. In general, treatment with a unilateral injection requires a higher dose, but produces fewer side effects.
  5. EMG guidance is used to locate the muscles, using a hollow needle so that the toxin can be injected through the needle. Alternatively, the injection can be performed transorally, with visual monitoring.
References 
  1. Blitzer A, Brin MF, Stewart CF. Botulinum toxin management of spasmodic dysphonia (laryngeal dystonia): a 12-year experience in more than 900 patients. Laryngoscope. 1998 Oct;108(10):1435-41.
  2. Bielamowicz S, Stager SV, Badillo A, Godlewski A. Unilateral versus bilateral injections of botulinum toxin in patients with adductor spasmodic dysphonia. J Voice. 2002 Mar;16(1):117-23.
  3. Watts CC, Whurr R, Nye C. Botulinum toxin injections for the treatment of spasmodic dysphonia. Cochrane Database Syst Rev. 2004;(3):CD004327.
  4. Tang CG, Novakovic D, Mor N, Blitzer A. Onabotulinum toxin A dosage trends over time for adductor spasmodic dysphonia: A 15-year experience. Laryngoscope. 2016 Mar;126(3):678-81. 

Pharmacology

Learning Objectives 
  1. Know that botulinum toxin is produced by Clostridium botulinum bacteria.
  2. Botulinum toxin is currently used widely in the treatment of SD and other dystonias.
  3. Know that it produces a focal temporary blockade neuromuscular transmission that weakens the injected muscle for several weeks.
  4. The toxin blocks the release of acetylcholine from the nerve terminal.
    1. Acetylcholine is present in vesicles in the nerve ending, and is normally released by a process of exocytosis.
    2. Botulinum toxin cleaves SNARE proteins, blocking vesicle fusion with the presynaptic membrane
  5. Know that there are several serotypes of Botulinum toxin, each with a unique site of action within the synaptic vesicle/membrane interaction.
References 
  1. Jankovic J. Botulinum toxin in clinical practice. J Neurol Neurosurg Psychiatry. 2004 Jul;75(7):951-7.
  2. Pirazzini M, Rossetto O, Eleopra R, Montecucco C. Botulinum Neurotoxins: Biology, Pharmacology, and Toxicology. Pharmacol Rev. 2017 Apr;69(2):200-235. 

Surgical Therapies

Learning Objectives 
  1. Understand that there are several described surgeries for treatment of SD, including thyroarytenoid myectomy, thyroplasty, selective laryngeal adductor denervation-reinnervation, laryngeal nerve crush, and recurrent laryngeal nerve transection.
  2. Know the following about unilateral recurrent laryngeal nerve transection:
    1. First described effective treatment for SD
    2. Can lead to dramatic reduction of vocal breaks
    3. May also be associated with breathy, weak voice as a result of the resulting vocal cord paralysis
  3. Know the following about thyroarytenoid myectomy
    1. Has been done transorally with laryngoscopic approach and also transcervically through a window in the thyroid cartilage
    2. Reduction in thyroarytenoid muscle function may lead to reduced symptoms of vocal cord spasm
    3. Can be associated with purposeful neurolysis of the terminal branches of the recurrent laryngeal nerve as they are within the paraglottic space
  4. Know the following about selective laryngeal adductor denervation-reinnervation
    1. The procedure involves transecting the adductor branches of the recurrent laryngeal nerves and reinnervation of the adductor branches using the ansa cervicalis nerves with the goal of restoring muscle tone without spasm
    2. Abductor branches of the recurrent laryngeal nerve branches are left intact to preserve airway patency during inhalation
    3. Initial breathiness due to denervation may improve as reinnervation provides improved tone
    4. Some patients will continue to have spasmodic symptoms and may require continued Botulinum toxin injections for symptomatic relief even after surgery
  5. Recognize the following about Type II thyroplasty
    1. It involves an anterior split of the thyroid cartilage (laryngofissure) and fixation of the left and right thyroid ala further apart from one another
    2. The resulting lateralization of the vocal folds reduces force of vocal fold closure and reduces symptomatic impact of vocal cord spasm
  6. Understand that there is no data that clearly demonstrates the superiority of one approach over another
References 
  1. Berke GS, Blackwell KE, Gerratt BR, Verneil A, Jackson KS, Sercarz JA. Selective laryngeal adductor denervation-reinnervation: a new surgical treatment for adductor spasmodic dysphonia. Ann Otol Rhinol Laryngol. 1999 Mar;108(3):227-31.
  2. Koufman JA, Rees CJ, Halum SL, Blalock D. Treatment of adductor-type spasmodic dysphonia by surgical myectomy: a preliminary report. Ann Otol Rhinol Laryngol. 2006 Feb;115(2):97-102.
  3. Nomoto M, Tokashiki R,Hiramatsu H, Konomi U, Motohashi R, Sakurai E, Toyomura F, Ueda Y, Inoue S, Tsukahara K, Suzuki M. The Comparison of Thyroarytenoid Muscle Myectomy and Type II Thyroplasty for Spasmodic Dysphonia. J Voice. 2015 Jul;29(4):501-6. 
  4. van Esch BF, Wegner I, Stegeman I, Grolman W. Effect of Botulinum Toxin and Surgery among Spasmodic Dysphonia Patients. Otolaryngol Head Neck Surg. 2017 Feb;156(2):238-254. 
  5. Sanuki T, Yumoto E. Long-term Evaluation of Type 2 Thyroplasty with Titanium Bridges for Adductor Spasmodic Dysphonia. Otolaryngol Head Neck Surg. 2017 Jul;157(1):80-84.

Rehabilitation

Learning Objectives 
  1. Know that speech language pathology is often helpful in establishing diagnosis of SD
  2. Understand that speech language pathologist directed voice therapy may improve patient coping mechanisms, but that it does directly impact the SD itself or improve results from Botox injection
References 
  1. Murry T, Woodson GE. Combined Modality Treatment of Adductor Spasmodic Dysphonia With Botulinum Toxin and Voice Therapy. J Voice. 1995 Dec;9(4):460-5.
  2. Silverman EP, Garvan C, Shrivastav R, Sapienza CM. Combined modality treatment of adductor spasmodic dysphonia. J Voice. 2012 Jan;26(1):77-86. 

Case Studies

  1. A 48-year-old woman presents with complaints of rough, effortful voice that has been getting progressively worse for the past few years. She notes that speaking in a falsetto improves ease of voicing. She denies a family history of dystonia and does not have writer’s cramp or other neurologic complaint. What other factors of her voice complaint would you want to elucidate on history? What in particular would you listen for on perceptual acoustic evaluation? What would you expect to see on laryngeal examination?
  2. A 54-year-old woman with known history of adductor spasmodic dysphonia is transitioning to your practice. She has had good relief of her symptoms with bilateral thyroarytenoid muscle Botulinum toxin injections in the past. She has questions for you about further chemodenervation – how would you answer her queries concerning:
    1. What are the side effects of Botulinum toxin injection?
    2. What can we do if I develop antibodies that limit benefit from continued injection?
    3. What are the surgical alternatives to Botulinum toxin injection?

Complications

Learning Objectives 
  1. Know that botulinum toxin therapy is very safe, and no serious complications have been reported.
  2. Understand that adverse side effects may include a breathy voice and mild dysphagia.
    1. If dysphagia is present, it is often with thin liquids and can be relieved by patient instructions to swallow carefully, perform a chin tuck during the swallow, and/or use thicker consistencies.
    2. When these problems occur, they usually resolve within two weeks.
    3. If the duration of side effects is longer, then the dose should be decreased for subsequent injections.
  3. A rare problem is the development of resistance to the toxin. In such cases, it would be possible to use an alternate serotype of toxin.
  4. Know that surgery creates permanent anatomic changes.
    1. The voice may be quite weak after denervation or muscle resection.
    2. If laryngeal abduction is impaired, then airway obstruction may be a significant problem.
References 
  1. Blitzer A, Brin MF, Stewart CF. Botulinum toxin management of spasmodic dysphonia (laryngeal dystonia): a 12-year experience in more than 900 patients. Laryngoscope. 1998 Oct;108(10):1435-41.
  2. Bielamowicz S, Stager SV, Badillo A, Godlewski A. Unilateral versus bilateral injections of botulinum toxin in patients with adductor spasmodic dysphonia. J Voice. 2002 Mar;16(1):117-23.
  3. van Esch BF, Wegner I, Stegeman I, Grolman W. Effect of Botulinum Toxin and Surgery among Spasmodic Dysphonia Patients. Otolaryngol Head Neck Surg. 2017 Feb;156(2):238-254. 
  4. Tang CG, Novakovic D, Mor N, Blitzer A. Onabotulinum toxin A dosage trends over time for adductor spasmodic dysphonia: A 15-year experience. Laryngoscope. 2016 Mar;126(3):678-81.

Review

Review Questions 
  1. What are the most common signs and symptoms of SD?
  2. What is the cause of SD?
  3. What are the physical signs of SD?
  4. What is the current treatment of choice?
Resources 

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