Usability and Feasibility of In-home Vibro-Tactile Stimulation for Treating Voice Symptoms in Laryngeal Dystonia

Laryngeal dystonia (LD) is associated with involuntary laryngeal muscle spasms that impair speech. Research established that vibrotactile stimulation (VTS) of the larynx can lead to short-term improvements in voice quality in LD. To determine its usability and potential effectiveness in nonclinical settings, this study evaluated a 2-month use of in-home VTS as a noninvasive treatment for LD.

Over 8 weeks, 32 LD participants applied 100-150Hz VTS to the laryngeal area in-home at a daily dosage of 20 minutes. A first cohort (n = 15) taped vibrators directly to the skin, the second cohort (n = 17) wore a custom-designed collar with embedded vibrators. Weekly dosage started at 3 days/week, increased to 6 days/week (week 4), with participants following a self-selected dosage plan in weeks 5-8. At every session, participants ranked Perceived Speech Effort (PSE; scale 1-10) and Voice Quality Change (VQC; scale 1-5).

During weeks 1-4, VTS reduced mean PSE within a session by 13.5% (range: -9% to 44%) with 63% (20/32) of participants exhibiting a reduction in speech effort in at least half the sessions. Over the 2-month period, 17 participants reported an improved VCQ with a mean increase from 2.9 (neutral) to 3.8 (noticeable). Relative VTS-induced PSE change was not significantly different for direct skin contact vs wearing the collar, between participants with and without Botulinum neurotoxin (BoNT) injections, or between adductor and abductor type of LD (P's > 0.05). The effects of VTS lasted between 0.5-24 hours in 53% and >1 day in 16% of participants.

VTS can reduce speech effort and improve voice quality in people with LD with repeatable effects and high patient acceptance. Results demonstrate that laryngeal VTS is a feasible, noninvasive in-home treatment option for LD, offering comparable effectiveness for abductor/adductor LD as well as for people with and without BoNT treatment.