An open-label study of sodium oxybate in Spasmodic dysphonia

Abstract

Objectives/hypothesis: Spasmodic dysphonia (SD) is a task-specific laryngeal dystonia that affects speech production. Co-occurring voice tremor (VT) often complicates the diagnosis and clinical management of SD. Treatment of SD and VT is largely limited to botulinum toxin injections into laryngeal musculature; other pharmacological options are not sufficiently developed.

Study design: Open-label study.

Methods: We conducted an open-label study in 23 SD and 22 SD/VT patients to examine the effects of sodium oxybate (Xyrem), an oral agent with therapeutic effects similar to those of alcohol in these patients. Blinded randomized analysis of voice and speech samples assessed symptom improvement before and after drug administration.

Results: Sodium oxybate significantly improved voice symptoms (P = .001) primarily by reducing the number of SD-characteristic voice breaks and severity of VT. Sodium oxybate further showed a trend for improving VT symptoms (P = .03) in a subset of patients who received successful botulinum toxin injections for the management of their SD symptoms. The drug's effects were observed approximately 30 to 40 minutes after its intake and lasted about 3.5 to 4 hours.

Conclusions: Our study demonstrated that sodium oxybate reduced voice symptoms in 82.2% of alcohol-responsive SD patients both with and without co-occurring VT. Our findings suggest that the therapeutic mechanism of sodium oxybate in SD and SD/VT may be linked to that of alcohol, and as such, sodium oxybate might be beneficial for alcohol-responsive SD and SD/VT patients.

Level of evidence: 4 Laryngoscope, 127:1402-1407, 2017.

Keywords: Laryngeal dystonia; Xyrem; alcohol.

Conflict of interest statement

Conflict of interest: None

© 2016 The American Laryngological, Rhinological and Otological Society, Inc.

Figures

Fig. 1

Effects of sodium oxybate (Xyrem®) on voice symptoms in patients with isolated SD (I,A–C) and in patients with combined SD and VT (II, A–D). Voice and speech recordings were examined for the quantitative assessment of the number of voice breaks, severity of harshness and breathiness as characteristics of SD and additionally the severity of VT as a characteristic of SD/VT before and 40 min after the drug intake.