Patient reported voice outcomes following multi-disciplinary approach to botulism toxin for spasmodic dysphonia

Spasmodic dysphonia (SD) is a debilitating disorder primarily affecting voice production. Current treatment includes repeat botulinum toxin (botox) injections for symptomatic management. The aim of this study is to review the impact of botox injections on patient reported outcome measures (PROM), using a novel and unique quality of life, proforma, and side effects in patients treated at our centre.

This retrospective case series evaluated all patients who were treated in our specialised voice clinic, at a single tertiary referral centre between May 2019 and April 2024 with botox for SD. The primary outcome measure was PROM of voice quality weekly post-injection as per a unique proforma. Variables extracted included patient demographics, treatment specifics and complications.

Fifty-two patients were included representing 21 (40.4%) males. Forty-two (80.8%) suffered from adductor spasmodic dysphonia with 8 (15.4%) having abductor dysphonia and 1 (1.92%) with mixed dysphonia. Patients with abductor dysphonia had a statistical improvement in voice following dose 2, (1.8-3.0, p=0.03) and dose 3 (1.4-3.2, p = <0.001). Patients with adductor dysphonia had significant improvements in voice following all doses (2.1-2.9, p=0.01), (1.9-3.0, p = <0.01) and (2.1-3.0, p = <0.01). The most common complication was a 'breathy voice', ranging from 31.4% to 51.0% but all patients reported this as transient.

Patient reported quality of voice is improved following botox injections for spasmodic dysphonia, and most patients do not suffer from long-term complications.