Thalamic Deep Brain Stimulation for Spasmodic Dysphonia: A Phase I Prospective Randomized Double-Blind Crossover...

Area of Science:

• Neurology
• Neurosurgery
• Speech Pathology

Background:

• Adductor spasmodic dysphonia (SD) is a neurological disorder affecting vocal fold function and speech.
• Current treatments involve repeated botulinum toxin injections to weaken laryngeal muscles.
• Deep brain stimulation (DBS) offers a novel therapeutic approach targeting the underlying neurological cause of SD.

Purpose of the Study:

• To evaluate the safety and efficacy of DBS as a treatment for adductor spasmodic dysphonia (SD).
• To assess the impact of DBS on voice quality and patient-reported quality of life.

Main Methods:

• A phase I randomized controlled trial involving six patients with SD.
• Patients received DBS targeting the ventral intermediate nucleus (Vim) of the thalamus.
• A blinded crossover design compared DBS 'on' and 'off' states, followed by open-label treatment.

Main Results:

• No complications were reported, indicating DBS is safe for SD patients.
• A significant trend towards improved quality of life (P=0.07) and voice quality (P=0.06) was observed when DBS was active.
• Secondary outcomes showed no cognitive changes, but improvements in mood and quality of life at one year.

Conclusions:

• Deep brain stimulation (DBS) is a safe treatment modality for adductor spasmodic dysphonia (SD).
• Blinded DBS demonstrated a strong trend for improving voice quality and quality of life, despite small sample size.
• Findings suggest the cerebellar circuit, rather than the pallidal circuit, is critical for vocal fold motor control in SD.