Spasmodic dysphonia and botulinum toxin: experience from the largest treatment series.

Spasmodic dysphonia is a focal laryngeal dystonia, with adductor, abductor, mixed, respiratory and singer's types. Our series over 24 years includes 1300 patients. 82% are of the adductor type; 63% were female; 12% had a positive family history and 82.4% had a focal distribution. All of the patients were managed with varying degrees of success with individualised dosing of botulinum neurotoxin A injected into the laryngeal musculature under EMG guidance.