The Mayo Clinic Arizona Spasmodic Dysphonia Experience: A Demographic Analysis of 718 Patients.

OBJECTIVE

Analyze demographic data collected over a 25-year experience of 718 patients with spasmodic dysphonia (SD) who have been treated with botulinum toxin-A (BoNT-A) and compare our data with previously published studies.

METHODS

Seven hundred eighteen patients with SD were treated with 6621 BoNT-A injections at Mayo Clinic Arizona between 1989 and 2014. All patients were treated by the same physician team. Background demographic data for each patient were recorded.

RESULTS

Of 718 patients, 557 patients were female (77.6%). Six hundred sixty of 718 (91.8%) patients had adductor SD (AdSD), and 58 of 718 (8.1%) patients had abductor SD (AbSD). Average age of onset was 51 years. Of 718 patients, 378 (52.6%) had vocal tremor (VT); VT was present in 54.4% of AdSD patients and 32.1% of AbSD patients. Thirty-seven of 718 (5.2%) patients had other dystonias, including cervical dystonia (2.3%), blepharospasm (1.4%), limb dystonia (1.1%), and oromandibular dystonia (0.3%). A positive family history of SD was present in only 6 of 718 patients (0.8%) and of other dystonias in 11 of 718 patients (1.5%).

CONCLUSIONS

Spasmodic dysphonia is a chronic and potentially disabling focal laryngeal dystonia. The Mayo Clinic Arizona SD experience compares to prior reports and reveals a female preponderance, onset in middle age, infrequent hereditary pattern, high co-occurrence of VT, and low co-occurrence of other dystonias.