A new Neuromodulation Treatment for a Speech Disorder

Spasmodic dysphonia (SD) is a rare neurological disorder that develops spontaneously during midlife. Patients with spasmodic dysphonia experience involuntary spasms of the laryngeal musculature during speech, typically resulting in a strained or choked voice quality. It makes oral communication an exhausting task, negatively affecting a patient’s personal and professional life. The disorder progresses gradually throughout the first year, and it usually remains a chronic condition for the rest of life.

At present, there is no cure for spasmodic dysphonia. It does not respond to available behavioral speech therapy. Current therapeutic options are limited and provide only temporary symptomatic relief. Standard treatment consists of periodic (every 2-3 months) clinic visits for botulinum toxin injection to the laryngeal muscles. However, approximately 60% of patients do not tolerate or poorly tolerate these injections, leading to some 30,000 patients in the US alone with no treatment options.

A team of researchers in the Human Sensorimotor Control Laboratory of Juergen Konczak showed recently that applying vibration to the skin above the voice box (Adam’s apple) can improve the voice quality in SD within 30 minutes of stimulation. By measuring cortical signals while patients vocalize and receive vibro-tactile stimulation (VTS) to the larynx, the group could show this form of somatosensory stimulation modulates the neural activity of the brain area that controls speech. Arash Mahnan, a biomedical engineer and doctoral student in the lab, currently works on translating the laryngeal VTS approach into a wearable device. This technology has the potential to become a low cost, non-invasive treatment for SD that could potentially augment or replace existing standard therapy such as Botox injections to the larynx.