Laryngeal Dystonias and Tremor

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Laryngeal Dystonias and Tremor

Laryngology, Voice and Swallowing
Author Credentials 

Claudio F. Milstein, PhD
Director, The Voice Center
Head and Neck Institute, Cleveland Clinic
9500 Euclid Ave, Cleveland, Ohio, 44195

Abie Mendelsohn, MD
Director of Heand & Neck Robotic Surgery
Department of Heand and Neck Surgery
David Geffen School of Medicine, UCLA

Module Summary

Laryngeal dystonias involve involuntary movements of the laryngeal muscles, and subtypes include adductor spasmodic dysphonia, abductor spasmodic dysphonia, and laryngeal respiratory dystonias. These can present with vocal tremor. The anatomy and pathophysiology are poorly understood. Incidence is significant higher in females. The treatment of choice is injections with Botox into the intrinsic and/or extrinsic laryngeal musculature, depending on the specific presentation. Voice therapy can be a good coadjuvant treatment in some cases. There are short-term side effects of Botox injections, and benefits last on average 3 months. Surgical procedures have been reported for adductor spasmodic dysphonia.

Module Learning Objectives 
  1. Recognize the signs and symptoms of laryngeal dystonias, including adductor and abductor spasmodic dysphonia, vocal tremor, and laryngeal respiratory dystonias.  
  2. Explain the pathophysiology, including type, area of neurologic damage, unique voice and laryngeal function of these neurolaryngological movement disorders.
  3. Describe the larygostroboscopic, and perceptual signs and vocal qualities associated with each condition.
  4. Summarize the role of therapeutic management for each of the distinct laryngeal disorders. 

Anatomy

Learning Objectives 
  1. Understand that spasmodic dysphonia is considered to be a disorder of central nervous system processing, but a precise mechanism is not well understood. 
  2. Recognize that altered brain function can affect the larynx in different ways, depending upon the localization of the affected area in the motor system. The type of laryngeal disorder is directly related to the brain/motor system area affected. 
References 
  1. Chhetri DK, Vinters HV, Blumin JH, Berke GS. Histology of Nerves and Muscles in Adductor Spasmodic Dysphonia. Ann Otol Rhinol Laryngol. 2003 Apr;112(4):334-41.

Pathogenesis

Learning Objectives 
  1. Understand that spasmodic dysphonia (SD)is a task-specific focal laryngeal dystonia characterized by irregular and uncontrolled vocal fold spasms resulting in voice breaks. The pathophysiology is poorly understood, and there are diagnostic difficulties. 
  2. Realize that although pathophysiology of spasmodic dysphonia is unknown, studies have found an increase of overall water diffusivity in the white matter along the corticobulbar/corticospinal tract.
  3. Know that there are different types of vocal tremors, that can manifest isolated to the vocal folds, or associated with tremor in other parts of the body, including upper extremities or head.
  4. Recognize that although relatively uncommon, there are laryngeal dystonias that affect primarily respiratory function, and not voice. 
References 
  1. Simonyan K, Tovar-Moll F, Ostuni J, Hallett M, Kalasinsky VF, Lewin-Smith MR, Rushing EJ, Vortmeyer AO, Ludlow CL.  Focal white matter changes in spasmodic dysphonia: a combined diffusion tensor imaging and neuropathological study. Brain. 2008 Feb;131(Pt 2):447-59. Epub 2007 Dec 14.
  2. Zwirner P, Dressler D, Kruse E.  Spasmodic laryngeal dyspnea: a rare manifestation of laryngeal dystonia. Eur Arch Otorhinolaryngol. 1997;254(5):242-5.

Incidence

Learning Objectives 
  1. Understand that the majority of patients with spasmodic dysphonia are female.
  2. Know that patients with spasmodic dysphonia have a significant incidence of both essential tremor and other dystonias (writer's cramp, blepharospasm, oromandibular dystonia). 
  3. Understand that there appear to be no significant environmental or hereditary patterns in the etiology of spasmodic dysphonia. Stress or viral infection may induce the onset of symptoms of spasmodic dysphonia among adults.
References 
  1. Schweinfurth JM, Bilante M, Courey MS. Risk Factors and Demographics in Patients With Spasmodic Dysphonia. Laryngoscope. 2002 Feb;112(2):220-3.

Genetics

Learning Objectives 

Understand that in some cases of laryngeal dystonias and tremor there is a known familial component and can be inherited. However, in many cases there is an absence of family history. 
 

References 
  1. Ludlow CL. Spasmodic Dysphonia: a Laryngeal Control Disorder Specific to Speech. J Neurosci. 2011 Jan 19;31(3):793-797.
  2. Elble RJ. Diagnostic criteria for essential tremor and differential diagnosis. Neurology. 2000;54(11 Suppl 4):S2-6.

Patient Evaluation

Learning Objectives 
  1. Understand that the diagnosis of spasmodic dysphonia can be difficult due to the lack of a scientific consensus on diagnostic criteria and the fact that other voice disorders may present similarly. 
    1. Know that spasmodic dysphonia and muscle tension dysphonia (MTD) are often confused. Spasmodic dysphonia symptoms are task-specific. MTD is not task specific and maintains consistent levels of severity across speech tasks.
  2. Recognize that case history may offer clues as to nature of the patient’s voice complaints.
    1. Onset, duration, severity, and progression are all important factors.
    2. Nature of the dysphonia (complaints of roughness vs breathiness vs effort, etc).
  3. Understand that perceptual evaluation is essential for the differential diagnosis of patients with SD.
    1. Adductor Spasmodic Dysphonia (ADSD) is characterized by strained voice, adductor spasms, perceived as stops in voice during sustained phonation or conversational speech, and delays in voice onset, particularly on words that start with a vowel. 
    2. Abductor Spasmodic Dysphonia (ABSD) is characterized by a weak, breathy voice, with breathy breaks, particularly after voiceless consonants. 
    3. Some patients will have better voice during certain tasks such as high pitch vocalizations, singing, laughing/crying, or imitation of a foreign accent. 
    4. Examination of vocal fold in motion using stroboscopy helps rule out other pathology, and can add information about vocal fold vibration and supraglottic compression. However, the spasms may not always be visualized with stroboscopy and the confirmation of the diagnosis is made by perceptual evauation with a trained ear. 
       
References 
  1. Braden MN, Hapner ER.  Listening: the key to diagnosing spasmodic dysphonia. ORL Head Neck Nurs. 2008 Winter;26(1):8-12.
  2. Daraei P, Villari CR, Rubin AD, Hillel AT, Hapner ER, Klein AM, Johns MM 3rd. The Role of Laryngoscopy in the Diagnosis of Spasmodic Dysphonia. JAMA Otolaryngol Head Neck Surg. 2014 Mar;140(3):228-32.
  3. Klotz DA, Maronian NC, Waugh PF, Shahinfar A, Robinson L, Hillel AD. Findings of Multiple Muscle Involvement in a Study of 214 Patients with Laryngeal Dystonia Using Fine-Wire Electromyography. Ann Otol Rhinol Laryngol. 2004 Aug;113(8):602-12.

Measurement of Functional Status

Learning Objectives 
  1. Know the minimal requirement to document vocal function is a standardized acoustic recording of the voice.  
    1. This is important to document function at presentation and its response to treatment.  
    2. An acoustic recording before and after treatment is important to monitor progress. 
  2. Know that computerized acoustic analyses of the voice are not essential, and can be performed post-hoc, on the recorded sample.  
  3. Understand that aerodynamic tests, such as phonatory airflow and pressure, may be useful.  
    1. Vocal breathiness is manifested by increased phonatory airflow.
    2. The pressure required to initiate phonation (minimal phonation pressure) is often increased, as patients are unable to speak softly.
References 
  1. Jiang JJ, Titze IR.  Measurement of vocal fold intraglottal pressure and impact stress. J Voice. 1994 Jun;8(2):132-44.
  2. Murry T, Woodson GE.  A Comparison of Three Methods for the Management of Vocal Fold Nodules. J Voice. 1992;6(3):271-276. 
  3. Rosen CA, Lombard LE, Murry T. Acoustic, aerodynamic, and videostroboscopic features of bilateral vocal fold lesions.  Ann Otol Rhinol Laryngol. 2000 Sep;109(9):823-8.
  4. Johns MM. Update on the etiology, diagnosis, and treatment of vocal fold nodules, polyps, and cysts. Curr Opin Otolaryngol Head Neck Surg. 2003 Dec;11(6):456-61. 

Imaging

Learning Objectives 
  1. Know that radiologic studies are not indicated or helpful.  
  2. Realize that endoscopic and stroboscopic assessment is useful to document vocal function and its response to treatment, and to educate the patient about the problem.  
  3. Recognize the further advances may include high-speed imaging.
References 
  1. Schwartz SR, Cohen SM, Dailey SH, Rosenfeld RM, Deutsch ES, Gillespie MB, Granieri E, Hapner ER, Kimball CE, Krouse HJ, McMurray JS, Medina S, O'Brien K, Ouellette DR, Messinger-Rapport BJ, Stachler RJ, Strode S, Thompson DM, Stemple JC, Willging JP, Cowley T, McCoy S, Bernad PG, Patel MM. Clinical practice guideline: hoarseness (dysphonia). Otolaryngol Head Neck Surg. 2009 Sep;141(3 Suppl 2):S1-S31. 
  2. Best SR, Akst LM. Visualizing the Larynx: Indirect and Direct Laryngoscopy. Comprehensive Textbook of Otolaryngology, 2014; eds. Sataloff R, Benninger M. Philadelphia: Jaypee Medical Publishing. 
  3. Patel RR, Liu L, Galatsanos N, Bless DM. Differential Vibratory Characteristics of Adductor Spasmodic Dysphonia and Muscle Tension Dysphonia on High-Speed Digital Imaging. Ann Otol Rhinol Laryngol. 2011 Jan;120(1):21-32.
  4. Stachler RJ, Francis DO, Schwartz SR, Damask CC, Digoy GP, Krouse HJ, McCoy SJ, Ouellette DR, Patel RR, Reavis CCW, Smith LJ, Smith M, Strode SW, Woo P, Nnacheta LC. Clinical Practice Guideline: Hoarseness (Dysphonia) (Update). Otolaryngol Head Neck Surg. 2018 Mar;158(1_suppl):S1-S42.

Treatment

Learning Objectives 
  1. Understand that the preferred treatment for symptom management is injections of botulinum toxin (BotoxTM) into the intrinsic laryngeal muscles with EMG guidance. Injections are repeated on average every three months, and have a high rate of success. Side effects are few and short term. 
    1. Botox results in muscle denervation by blocking the release of acetylcholine at the neuromuscular junction. 
    2. For ADSD, injections are primarily given into one or both thyroarytenoid muscles. For ABSD, injections are primarily given into the posterior cricoarytenoid muscles. 
    3. If extralaryngeal muscles are involved in vocal tremor, targeted Botox injections to the strap musculature may offer improved results
  2. Know that voice therapy as administered by a specialized Speech Language Pathology can be used in conjunction with Botox injections to help maximize voice efficiency in certain patients with spasmodic dysphonia and tremor.
     
References 
  1. Brin MF, Blitzer A, Stewart C, Fahn S. Treatment of spasmodic dysphonia (laryngeal dystonia) with local injections of botulinum toxin: Review and technical aspects. In A. Blitzer, M. F. Brin, & S. Fahn (Eds.), Neurological disorders of the larynx New York: Thieme; 1992.
  2. Blitzer, A. Spasmodic Dysphonia and Botulinum Toxin: Experience from the Largest Treatment Series. Eur J Neurol. 2010 Jul;17 Suppl 1:28-30. 
  3. Ludlow CL. Mann EA. Management of spasmodic dysphonia. In Rubin JS, Sataloff RT, Korovin, SG (Eds.) Diagnosis and treatment of voice disorders (2nd ed.) San Diego,CA. Singular; 2005. 
  4. Barkmeier-Kraemer, J, Lato A, Wiley K. Development of a Speech Treatment Program for a Client with Essential Vocal Tremor. Semin Speech Lang. 2011 Feb;32(1):43-57. 
  5. Gurey LE, Sinclair CF, Biltzer A. A new paradigm for the management of essential vocal tremor with botulinum toxin.  Laryngoscope.  2013;123(10), 2497–2501.

Surgical Therapies

Learning Objectives 
  1. Know that there are some operative approaches for treatment of ADSD. Long term results of these procedures appear promising. 
    1. Selective laryngeal adductor denervation and reinnervation 
    2. Type II Thyroplasty 
  2. Surgical approaches for ABSD have been reported with less successful outcomes
    1. Medialization Type I Thyroplasty
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. Annals of Otology, Rhinology & Laryngology. 1999;108(3), 227–231.
  2. Sanuki T, Isshiki N. Overall Evaluation of Effectiveness of Type II Thyroplasty for Adductor Spasmodic Dysphonia.  Laryngoscope. 2007;117(12):2255–2259. 
  3. Isshiki, N. Progress in Laryngeal Framework Surgery. Acta Oto-Laryngologica. 2000 Mar;120(2):120–127.
     

Rehabilitation

Learning Objectives 
  1. Understand that voice therapy should be used before considering surgery.  
  2. Realize that after surgery, a course of voice therapy is indicated to teach behavioral change that might prevent recurrence.
References 
  1. Leonard R. Voice therapy and vocal nodules in adults. Curr Opin Otolaryngol Head Neck Surg. 2009 Dec;17(6):453-7.

Case Studies

  1. A 45 year old female is referred to you by a speech pathologist in the area. She was diagnosed with muscle tension dysphonia by an ENT and underwent 5 sessions of voice therapy with no voice improvement. She continues to experience vocal strain in conversations, feels that some words are more difficult to say than others, and can’t project her voice, which sounds hoarse all the time. During your evaluation, you notice that when she laughs, her voice briefly sounds significantly better. What diagnosis do you suspect in this patient?  How would you evaluate her vocal function?  What next steps would you take in treatment of this problem?
  2. A 65 year old male presents with a voice complaint of unsteady and wobbly voice quality, which has been progressively getting worse over the last year. He states that he has been evaluated by a neurologist, who diagnosed him with essential tremor, and treated him with propranolol and primidone. His head and hands tremor got significantly better, but his voice has continued to deteriorate. Explain the different steps in your evaluation, what laryngostroboscopic parameters would you assess, and what specific vocal tasks would you use to help you determine the nature of the disorder. What are two treatment options you would recommend for this patient? 
  3. A pulmonologist refers a patient to you for evaluation. He states that the case is puzzling. This is a 23 year old female with a two year history of gradually progressive shortness of breath. Diagnosed with asthma, but currently asthma treatments are not effective. She does not have episodic SOB, but complains of feeling breathless during all awake hours, and lately she has developed a stridor, more prominent on exertion. Recent spirometry was normal. Paradoxical vocal fold motion was suspected, but the patient failed to respond to respiratory therapy for this disorder. Explain what diagnosis do you suspect in this patient?  How would you confirm it, and how would you treat it?
     

Complications

Learning Objectives 

Realize that patients often experience short-term side effects of breathy voices and swallowing problems after injections with Botox. A careful discussion with the patient regarding these side effects is essential prior administration of each injection, to help find the optimal dose for each patient that would result in the best possible voice, but minimizing severity and length of side effects. 

References 
  1. Blitzer, A. Spasmodic dysphonia and botulinum toxin: experience from the largest treatment series. Eur J Neurol. 2010 Jul;17 Suppl 1:28-30.
  2. Ford CN, Bless DM, Patel NY. Botulinum toxin treatment of spasmodic dysphonia: Techniques, indications, efficacy. J Voice. 1992;6(4):370–376. 
     

Review

Review Questions 
  1. What are the presenting symptoms of abductor spasmodic dysphonia?
  2. What factors on the case history and what vocal tasks are important to elicit in a patient with a suspected laryngeal dystonia to help with the differential diagnosis?
  3. What is the first step in management of vocal tremor?
  4. What are target muscles and appropriate dose of Botox for a first-time injection in an elderly petite female who presents with severe adductor spasmodic dysphonia with tremor?
     
Resources 

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