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The Laryngoscope V C 2013 The American Laryngological, Rhinological and Otological Society, Inc.

A New Paradigm for the Management of Essential Vocal Tremor With Botulinum Toxin

Lowell E. Gurey, MD; Catherine F. Sinclair, MD; Andrew Blitzer, MD, DDS

Objectives/Hypothesis: 1) To clarify essential voice tremor (EVT) phenomenology; 2) To report a management para digm for essential voice tremor using botulinum toxin. Study Design: Retrospective analysis of prospectively collected data. Methods: Phenomenology from patients diagnosed with EVT between April 1996 and March 2012 was recorded, charted, and analyzed. A paradigm for treatment of EVT using botulinum toxin based on individualized clinical findings is discussed. Results: Sixteen patients were included. Fewer than 50% patients were responsive to centrally acting oral medications. Fifteen patients analyzed had horizontal laryngeal tremor and received botulinum toxin injections to bilateral thyroarytenoid muscles. Thirteen patients had a vertical laryngeal tremor, and these patients underwent additional strap muscle injections. All patients had symptomatic improvement with reduced tremor amplitude. Dose adjustments over time depended on degree of symptomatic improvement. Conclusions: Management of essential voice tremor with botulinum toxin is optimized by individualizing treatment based on the tremor phenomenology observed during clinical examination. Key Words: Essential tremor, essential voice tremor, voice tremor, botulinum toxin, movement disorders. Level of Evidence: 4. Laryngoscope , 123:2497–2501, 2013

attention of a voice specialist. 13–15 Also, EVT can occur in patients with coexisting disorders of the larynx and laryngeal manifestations of other neurological disease such as dystonia (spasmodic dysphonia), Parkinson’s dis ease, or muscle tension dysphonia (MTD), resulting in increased difficulty in making the correct diagnosis. 16–24 The purposes of this study were to help clarify the phe nomenology of EVT, assist in differentiating this condi tion from other tremor disorders of the larynx, and report a new management paradigm for EVT using botu linum toxin. MATERIALS AND METHODS All patients diagnosed with EVT between April 1996 and March 2012 at a tertiary neurolaryngology referral practice who underwent evaluation and botulinum toxin injection were included in this study. Charts were reviewed following Institu tional Review Board approval. All patients were evaluated by a movement disorders neurologist either prior to or immediately following initial evaluation to assess for potential alternate eti ologies, presence of tremor in other body parts, coexisting dys tonic symptoms, and to institute/manage treatment with systemic oral medications. Written informed consent was obtained prior to toxin injection. Outcome Measures Data was collected on patient demographics, disease char acteristics, and diagnostic considerations. At the time of each office visit, patients were asked to rate their maximal response to the preceding toxin injection on a previously validated 0% to 100% of normal function rating scale. 16 This prospectively col lected data was analyzed, as were other toxin management

INTRODUCTION Essential tremor (ET) is among the most common adult onset movement disorders. 1–3 Although often con sidered a benign condition, ET can lead to severe func tional disability in up to 75% of patients, resulting in significant physical and psychological handicap. 3–7 ET can affect the head, neck, face, tongue, jaw, trunk, and lower limbs. 3,8–11 Essential voice tremor (EVT) is the phonatory manifestation of ET and can lead to increased vocal effort, decreased intelligibility, and misconstrued emotional state. The stress of the vocal handicap will of ten exacerbate the tremor, causing patients to become reclusive. EVT is secondary to involuntary oscillation of the muscles of speech and sound production, leading to rhythmic alterations in pitch and loudness, and may even cause complete arrest in phonation. 12 An estimated one-quarter of patients with ET may have EVT; how ever, symptoms are often attributed to the normal aging process, with only a small minority ever seeking the From the New York Center for Voice and Swallowing Disorders, St. Luke’s Roosevelt Medical Center, New York, New York, U.S.A Editor’s Note: This Manuscript was accepted for publication February 2, 2013. Presented at the 2012 American Laryngological Association Spring meeting and winner of the Best Resident/Fellow paper, San Diego, CA The authors have no funding, financial relationships, or conflicts of interest to disclose. Send correspondence to Andrew Blitzer, MD, DDS, FACS, New York Center for Voice and Swallowing Disorders, St. Luke’s Roosevelt Medical Center, 425 West 59th Street, 10th Floor, New York, NY 10019. E-mail: ab1136@aol.com

DOI: 10.1002/lary.24073

Laryngoscope 123: October 2013

Sinclair et al.: Botulinum Toxin Injection for Essential Vocal Tremor 2497