Trial Outcomes & Findings for Usability of Vibro-tactile Stimulation to Treat Spasmodic Dysphonia (NCT NCT06111027)

Last Updated: 2026-07-15

Results Overview

Voice Quality Change (VQC) was self-assessed using a 5-point Likert scale (1 = very unnoticeable, 5 = very noticeable; 3 = neutral). Ratings were recorded at the end of each VTS session. The score reflects the overall longitudinal change in symptoms experienced after treatment end. VQC at week 8 was computed as the mean of the last three sessions of the study.

Recruitment status

COMPLETED

Study phase

PHASE1/PHASE2

Target enrollment

40 participants

Primary outcome timeframe

Week 8

Results posted on

2026-07-15

Participant Flow

Data collection occurred between the 21st November 2023 and the 28th October 2024. Recruitment ended on 29th October 2024. A total of 40 participants were enrolled. Of these, 34 participants began study procedures and 32 participants completed the study.

Participant milestones

Participant milestones
Measure	Intervention Participants received vibro-tactile stimulation as a non-invasive treatment option. Stimulators were a pair of light-weight encapsulated cylindrical vibrators to both sides of the larynx (voice box). The vibration frequency for VTS was set be to 100Hz. During VTS, participants feel a mild tingling or vibrating sensation at their larynx. They applied VTS at home over a period of 8 weeks with a daily dosage of 20 minutes. During weeks 1-4, the weekly dosage of VTS was gradually increased (week 1: 3 days/wk; week 2: 4 days/wk; week 3: 5 days/wk; week 4: 6 days/wk). During weeks 5-8, participants applied VTS on self-selected days as needed, not exceeding 6 times a week.
Overall Study STARTED	40
Overall Study COMPLETED	32
Overall Study NOT COMPLETED	8

Reasons for withdrawal

Reasons for withdrawal
Measure	Intervention Participants received vibro-tactile stimulation as a non-invasive treatment option. Stimulators were a pair of light-weight encapsulated cylindrical vibrators to both sides of the larynx (voice box). The vibration frequency for VTS was set be to 100Hz. During VTS, participants feel a mild tingling or vibrating sensation at their larynx. They applied VTS at home over a period of 8 weeks with a daily dosage of 20 minutes. During weeks 1-4, the weekly dosage of VTS was gradually increased (week 1: 3 days/wk; week 2: 4 days/wk; week 3: 5 days/wk; week 4: 6 days/wk). During weeks 5-8, participants applied VTS on self-selected days as needed, not exceeding 6 times a week.
Overall Study Adverse Event	2
Overall Study Withdrawal by Subject	6

Baseline Characteristics

Usability of Vibro-tactile Stimulation to Treat Spasmodic Dysphonia

Baseline characteristics by cohort

Baseline characteristics by cohort
Measure	Vibro-tactile Stimulation Treatment n=32 Participants Participants received vibro-tactile stimulation as a non-invasive treatment option. Stimulators were a pair of light-weight encapsulated cylindrical vibrators attached to to both sides of the larynx (voice box) either by taping them directly to the skin or by wearing them in a collar (no direct skin contact). The vibration frequency for VTS was set to 100Hz. During VTS, participants feel a mild tingling or vibrating sensation at their larynx. They applied VTS at home over a period of 8 weeks with a daily dosage of 20 minutes. During weeks 1-4, the weekly dosage of VTS was gradually increased (week 1: 3 days/wk; week 2: 4 days/wk; week 3: 5 days/wk; week 4: 6 days/wk). During weeks 5-8, participants applied VTS on self-selected days as needed, not exceeding 6 times a week.
Age, Categorical <=18 years	0 Participants n=20 Participants
Age, Categorical Between 18 and 65 years	16 Participants n=20 Participants
Age, Categorical >=65 years	16 Participants n=20 Participants
Age, Continuous	62.3 Years STANDARD_DEVIATION 15.2 • n=20 Participants
Sex: Female, Male Female	21 Participants n=20 Participants
Sex: Female, Male Male	11 Participants n=20 Participants
Race (NIH/OMB) American Indian or Alaska Native	1 Participants n=20 Participants
Race (NIH/OMB) Asian	0 Participants n=20 Participants
Race (NIH/OMB) Native Hawaiian or Other Pacific Islander	0 Participants n=20 Participants
Race (NIH/OMB) Black or African American	0 Participants n=20 Participants
Race (NIH/OMB) White	31 Participants n=20 Participants
Race (NIH/OMB) More than one race	0 Participants n=20 Participants
Race (NIH/OMB) Unknown or Not Reported	0 Participants n=20 Participants
Perceived Speech Effort	5.5 Score on a scale of 1-10 STANDARD_DEVIATION 1.3 • n=20 Participants

PRIMARY outcome

Timeframe: Week 4

Perceived Speech Effort was self-rated by participants on a 0-10 scale (0 = no effort, 10 = maximum effort) while reading standardized sentences at habitual pitch and loudness. Ratings were collected immediately before and after each vibro-tactile stimulation session. The PSE value reported here reflects the group mean at week 4.

Outcome measures

Outcome measures
Measure	Intervention n=32 Participants Participants received vibro-tactile stimulation (VTS) as a non-invasive treatment option. They applied VTS at home over a period of 8 weeks with a daily dosage of 20 minutes. During weeks 1-4, the weekly dosage of VTS was gradually increased (week 1: 3 days/wk; week 2: 4 days/wk; week 3: 5 days/wk; week 4: 6 days/wk). During weeks 5-8, participants applied VTS on self-selected days as needed, not exceeding 6 times a week.
Perceived Speech Effort (PSE) at Week 4	4.8 Score on a scale of 1-10 Standard Deviation 1.3 • Interval -0.96 to -0.53

PRIMARY outcome

Timeframe: Week 8

Outcome measures

Outcome measures
Measure	Intervention n=32 Participants Participants received vibro-tactile stimulation (VTS) as a non-invasive treatment option. They applied VTS at home over a period of 8 weeks with a daily dosage of 20 minutes. During weeks 1-4, the weekly dosage of VTS was gradually increased (week 1: 3 days/wk; week 2: 4 days/wk; week 3: 5 days/wk; week 4: 6 days/wk). During weeks 5-8, participants applied VTS on self-selected days as needed, not exceeding 6 times a week.
Perceived Speech Effort (PSE) at Week 8	4.4 Score on a scale Standard Deviation 1.5 • Interval -1.06 to -0.38

PRIMARY outcome

Timeframe: Week 1

Voice Quality Change (VQC) was self-assessed using a 5-point Likert scale (1 = very unnoticeable, 5 = very noticeable; 3 = neutral). Ratings were recorded at the end of each VTS session. VQC at week 1 represents a baseline measure of symptom severity. It was computed as the mean of the first three sessions of VTS of the study.

Outcome measures

Outcome measures
Measure	Intervention n=32 Participants Participants received vibro-tactile stimulation (VTS) as a non-invasive treatment option. They applied VTS at home over a period of 8 weeks with a daily dosage of 20 minutes. During weeks 1-4, the weekly dosage of VTS was gradually increased (week 1: 3 days/wk; week 2: 4 days/wk; week 3: 5 days/wk; week 4: 6 days/wk). During weeks 5-8, participants applied VTS on self-selected days as needed, not exceeding 6 times a week.
Voice Quality Change (VQC) at Week 1	2.9 Unitless score on a scale between 1-5 Standard Deviation 0.6

PRIMARY outcome

Timeframe: Week 8

Outcome measures

Outcome measures
Measure	Intervention n=32 Participants Participants received vibro-tactile stimulation (VTS) as a non-invasive treatment option. They applied VTS at home over a period of 8 weeks with a daily dosage of 20 minutes. During weeks 1-4, the weekly dosage of VTS was gradually increased (week 1: 3 days/wk; week 2: 4 days/wk; week 3: 5 days/wk; week 4: 6 days/wk). During weeks 5-8, participants applied VTS on self-selected days as needed, not exceeding 6 times a week.
Voice Quality Change (VQC) at Week 8	3.8 Unitless score on a scale between 1-5 Standard Deviation 0.4

SECONDARY outcome

Timeframe: 8 weeks

Relative change in PSE (rPSE) was calculated as \[(Post - Pre) / Pre\] × 100. The between-group difference in mean rPSE comparing VTS received during direct skin contact vs. VTS collar was assessed over the total study period of 8 weeks to understand if the VTS applied directly to the skin was more effective in reducing speech effort than VTS applied via the collar.

Outcome measures

Outcome measures
Measure	Intervention n=32 Participants Participants received vibro-tactile stimulation (VTS) as a non-invasive treatment option. They applied VTS at home over a period of 8 weeks with a daily dosage of 20 minutes. During weeks 1-4, the weekly dosage of VTS was gradually increased (week 1: 3 days/wk; week 2: 4 days/wk; week 3: 5 days/wk; week 4: 6 days/wk). During weeks 5-8, participants applied VTS on self-selected days as needed, not exceeding 6 times a week.
Relative Change in Perceived Speech Effort (rPSE) for VTS Application Method	2.3 Percentage Interval -10.4 to 5.8

SECONDARY outcome

Timeframe: Week 1-4

Number of participants who completed at least 80% of prescribed VTS sessions during the intervention period.

Outcome measures

Outcome measures
Measure	Intervention n=32 Participants Participants received vibro-tactile stimulation (VTS) as a non-invasive treatment option. They applied VTS at home over a period of 8 weeks with a daily dosage of 20 minutes. During weeks 1-4, the weekly dosage of VTS was gradually increased (week 1: 3 days/wk; week 2: 4 days/wk; week 3: 5 days/wk; week 4: 6 days/wk). During weeks 5-8, participants applied VTS on self-selected days as needed, not exceeding 6 times a week.
Adherence Rate (Feasibility)	30 Participants

Adverse Events

Intervention

Serious events: 0 serious events

Other events: 2 other events

Deaths: 0 deaths

Serious adverse events

Adverse event data not reported

Other adverse events

Other adverse events
Measure	Intervention n=32 participants at risk Participants received vibro-tactile stimulation as a non-invasive treatment option. Stimulators were a pair of light-weight encapsulated cylindrical vibrators attached to to both sides of the larynx (voice box) either by taping them directly to the skin or by wearing them in a collar (no direct skin contact). The vibration frequency for VTS was set to 100Hz. During VTS, participants feel a mild tingling or vibrating sensation at their larynx. They applied VTS at home over a period of 8 weeks with a daily dosage of 20 minutes. During weeks 1-4, the weekly dosage of VTS was gradually increased (week 1: 3 days/wk; week 2: 4 days/wk; week 3: 5 days/wk; week 4: 6 days/wk). During weeks 5-8, participants applied VTS on self-selected days as needed, not exceeding 6 times a week.
Ear and labyrinth disorders Worsening of pre-existing tinnitus	3.1% 1/32 • Number of events 1 • Adverse events were collected from the start of the intervention through the end of the study period (e.g., after 8 weeks of home-based VTS use).
Ear and labyrinth disorders New-onset tinnitus	3.1% 1/32 • Number of events 1 • Adverse events were collected from the start of the intervention through the end of the study period (e.g., after 8 weeks of home-based VTS use).

Additional Information

Jürgen Konczak, Ph.D.

University of Minnesota

Phone: 612-624-4370

Email: [email protected]

Results disclosure agreements

Principal investigator is a sponsor employee
Publication restrictions are in place