title: Botulinum toxin injection for treatment of spasmodic dysphonia: experience at Srinagarind Hospital.
abstract: BACKGROUND
  Spasmodic dysphonia (SD) is a focal dystonia and adductor SD is the most common form. The standard treatment for adductor SD is EMG-guided, transcutaneous injections of botulinum toxin into the thyroarytenoid muscle.
  
  
  OBJECTIVE
  Report the clinical presentation of SD, treatment with botulinum toxin injection, injection technique, results, and adverse effects.
  
  
  METHODS
  A reviewed of clinical records of patients diagnosed with SD at the Voice Clinic between April 1999 and December 2004 at Srinagarind Hospital, Khon Kaen University, Thailand. Thirty-seven patients were identified but only twenty-five were treated with EMG-guided botulinum toxin injection to the thyroarytenoid muscle.
  
  
  RESULTS
  In the presented 37 patients, SD was more common in women (89%) than men (11%). The median duration of symptoms prior to diagnosis was 12 months: all were the adductor type. The average age at onset was 46 years. The presenting symptoms included influence to the voice (84%), hoarseness (70%), strained or strangled voice (65%), decreased loudness (27%), and breathy voice (22%). A vocal tremor coexisted with dystonia in 60% of the presented patients. Treatment with botulinum toxin injection was carried out on 25 patients for 78 injections (mean, 3 per patient). The time for botulinum toxin to take effect averaged 2.3 days (peak effect, 7 days). The patients received substantial relief from their SD symptoms, an average functional improvement of 39.2% (37.6% initially vs. 76.8% finally). Patients' best voice was achieved within one week and persisted for an average of 13.6 weeks. Side effects from the injections included mild breathiness (68%) and mild choking on fluid (56%). After injection, decreased potential for volume was a common complaint, but since all of the patients experienced increased fluency, they were satisfied. Almost all of the patients returned for repeat injections when the benefit diminished.
  
  
  CONCLUSIONS
  Botulinum toxin therapy has become the standard care for the treatment of SD. An acceptable and flexible treatment plan to produce a balance between decreased spasms and loss of function must be developed for each patient.
authors.affiliation: Department of Otolaryngology, Faculty of Medicine, Khon Kaen University 40002, Thailand. ssrirompotong@yahoo.com
authors.forename: Supaporn
authors.initials: S
authors.lastname: Srirompotong
authors.forename: Patchareeporn
authors.initials: P
authors.lastname: Saeseow
authors.forename: Rattana
authors.initials: R
authors.lastname: Taweesaengsuksakul
authors.forename: Samerduan
authors.initials: S
authors.lastname: Kharmwan
authors.forename: Somchai
authors.initials: S
authors.lastname: Srirompotong
mesh_terms: D001905:Botulinum Toxins / Q000627:therapeutic use*; D004576:Electromyography; D005260:Female; D006801:Humans; D007267:Injections; D007821:Laryngeal Muscles / Q000187:drug effects; D008297:Male; D008875:Middle Aged; D013035:Spasm / Q000188:drug therapy*; D016896:Treatment Outcome; D014832:Voice Disorders / Q000188:drug therapy*
chemical_list: D001905:Botulinum Toxins