The impact of long-term botulinum toxin injections on symptom severity in patients with spasmodic dysphonia.
Injection of botulinum toxin (BT) into the muscles of the larynx is an effective treatment for the symptoms of spasmodic dysphonia (SD). To date, however, there have been no studies that have used blinded raters to assess the efficacy of BT injections on overall symptom severity in a cohort of SD patients followed over a prolonged period. In this study, 102 subjects with SD were treated with serial BT injections for up to 2 years. Voice recordings were obtained at several time points during treatment and were played to a panel of expert and novice listeners who rated them based on overall symptom severity in a single-blind fashion. Subjects demonstrated significant improvement over baseline at all time points. In addition, patients showed a sustained responsiveness to therapy over time. These results provide support for the efficacy of serial BT injections for SD and suggest that successful treatment may depend, in part, on patients' early recognition of returning symptoms.
Division of Otolaryngology/Head and Neck Surgery, University of California, San Diego School of Medicine, La Jolla, CA 92103-8895, USA.
John F
JF
Damrose
Stephen N
SN
Goldman
Erik J
EJ
Groessl
Lisa A
LA
Orloff
D000368:Aged; D000704:Analysis of Variance; D018726:Anti-Dyskinesia Agents / Q000008:administration & dosage / Q000627:therapeutic use*; D001905:Botulinum Toxins / Q000008:administration & dosage / Q000627:therapeutic use*; D016022:Case-Control Studies; D015331:Cohort Studies; D004576:Electromyography; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007273:Injections, Intramuscular / Q000379:methods; D007821:Laryngeal Muscles / Q000187:drug effects / Q000502:physiology; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D015203:Reproducibility of Results; D016037:Single-Blind Method; D013067:Speech Perception; D013637:Tape Recording; D016896:Treatment Outcome; D014832:Voice Disorders / Q000188:drug therapy*
D018726:Anti-Dyskinesia Agents; D001905:Botulinum Toxins