けいれん性発声障害の治療における振動触覚刺激の有用性

実験的：Intervention

Laryngeal vibro-tactile stimulation

デバイス：Vibro-tactile stimulation

Participants received vibro-tactile stimulation (VTS) as a non-invasive treatment option. Stimulators were a pair of light-weight encapsulated cylindrical vibrators applied 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.

Perceived Speech Effort (PSE) at 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.

Perceived Speech Effort (PSE) at Week 8

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 8.

Voice Quality Change (VQC) at 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.

Voice Quality Change (VQC) at Week 8

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.

Relative Change in Perceived Speech Effort (rPSE) for VTS Application Method

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.

Adherence Rate (Feasibility)

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