Interarytenoid muscle botox injection for treatment of adductor spasmodic dysphonia with vocal tremor.
OBJECTIVE
Up to one-third of patients presenting with adductor spasmodic dysphonia will have an associated vocal tremor. These patients may not respond fully to treatment using thyroarytenoid (TA) muscle botulinum toxin (Botox) injection. Treatment failures are attributed to the involvement of multiple muscle groups in the tremor. This study evaluates the results of combined interarytenoid (IA) and TA muscle Botox injection in a group of 27 patients with adductor spasmodic dysphonia and vocal tremor and in four patients with severe vocal tremor alone.


METHODS
Patient-satisfaction data were reviewed retrospectively. Pre- and postinjection acoustic data were collected prospectively.


METHODS
Acoustic measures of fundamental frequency and cycle-by-cycle variability in frequency (jitter) and intensity (shimmer) were obtained from 15 patients' sustained vowel productions. Measures were collected after TA muscle injection, alone, and after combined TA and IA (TA+IA) muscle injections. In addition, two experienced voice clinicians blindly assessed tremor severity from recordings made for each patient in the two conditions. Patients were also queried regarding their satisfaction with the results of the injections and whether they desired to continue receiving TA+IA treatment.


RESULTS
Significant improvement in all acoustic measures except for % jitter was observed after the TA+IA muscle injections. Listeners identified voice samples after TA+IA muscle injections as demonstrating less tremor in 73% of the paired comparisons. Sixty-seven percent of the patients with spasmodic dysphonia and vocal tremor wished to continue to receive IA muscle injections. Only one patient with severe vocal tremor wished to continue with injections.


CONCLUSIONS
The addition of an IA muscle Botox injection to the treatment of patients with a combination adductor spasmodic dysphonia and vocal tremor may improve voice outcomes.
Kendall
Katherine A
KA
Department of Otolaryngology, University of Minnesota, Minneapolis, Minnesota, USA. katherine.kendall@va.gov
Leonard
Rebecca J
RJ
D019274:Botulinum Toxins, Type A / Q000008:administration & dosage* / Q000009:adverse effects; D055154:Dysphonia / Q000188:drug therapy* / Q000503:physiopathology; D006801:Humans; D007273:Injections, Intramuscular; D007821:Laryngeal Muscles / Q000187:drug effects* / Q000503:physiopathology; D009465:Neuromuscular Agents / Q000008:administration & dosage* / Q000009:adverse effects; D017060:Patient Satisfaction; D011446:Prospective Studies; D012189:Retrospective Studies; D012720:Severity of Illness Index; D012815:Signal Processing, Computer-Assisted; D013018:Sound Spectrography; D013061:Speech Acoustics; D013068:Speech Production Measurement; D011795:Surveys and Questionnaires; D016896:Treatment Outcome; D014833:Voice Quality
D009465:Neuromuscular Agents; D019274:Botulinum Toxins, Type A