Laryngeal Vibration to Treat Abductor-Type Laryngeal Dystonia: Effectiveness and Cortical Response.

Abstract

Demonstrate proof-of-concept that superficial vibro-tactile stimulation (VTS) of the larynx can serve as a non-invasive neuromodulation method to reduce voice symptoms in people with abductor-type laryngeal dystonia (ABLD) and record the underlying neural response to VTS of the somatosensory-motor cortex. Using a wearable collar with embedded vibrators, 11 people with ABLD received VTS for 24 min. To assess voice effects, they vocalized vowels and spoke standardized test sentences and words. Cortical activity was recorded using 64-channel EEG. Smoothed cepstral peak prominence, cumulative word and sentence duration were derived from voice recordings as objective markers of speech quality next to perceived speech effort as a subjective marker. In response to VTS, 64% of participants rated their improvement in voice quality as noticeable to very noticeable. Analysis of objective voice measures indicated a reduction in voice symptoms in up to 45% of participants immediately after and/or 20 min past the cessation of VTS. The cortical response to VTS application was a reduced event-related spectral power in theta, alpha, and beta bands over left and right somatosensory-motor cortical areas that was most prominent over the left premotor cortex in 7/11 participants. Applying laryngeal VTS proved to be feasible and safe. VTS can induce acute short-term reductions in voice symptoms, which is important given the limited therapeutic options for ABLD. The electrocortical correlate of VTS was an event-related desynchronization of neuronal firing patterns over bilateral somatosensory-motor cortex.