The effect of patient factors on response outcomes to Botox treatment of spasmodic dysphonia

Injection of botulinum toxin (Botox) into the laryngeal muscles has become the treatment of choice for controlling the symptoms of spasmodic dysphonia (SD). Currently, no specific battery of objective tests to assess the outc ome is universally accepted. The purpose of this study was to investigate d emographic, clinical, and treatment factors with voice outcome following Bo tox injection. Sixty-eight patients with adductor SD who underwent at least one Botox injection during a 5-year period were studied. Voice outcome mea sures were made from patient self-reporting scales and included overall voc al quality, length of response, and duration of breathiness. Vocal quality was significantly correlated with the underlying severity of vocal symptoms prior to treatment, incidence of breathiness and unilateral versus bilater al injection. The length of response was greater in males and following bil ateral injections. An increased period of breathiness significantly correla ted with bilateral injections.