Objectives: We investigated the relationship between muscle tension dysphonia (MTD) type 1 and soft phonation index (SPI) and evaluated the effect of voice therapy on MTD type 1.
Patients and methods: The study included 20 patients (all females; mean age 27+/-6 years) whose diagnosis was made as MTD type 1 on videolaryngostroboscopic examination. Acoustic analysis was performed before and after voice therapy using the Multi-Dimensional Voice Program. Acoustic parameters were compared with those of a control group comprising 20 females (mean age 28+/-4 years) without any voice problem.
Results: In the patient group, 19 patients exhibited a significantly increased SPI compared to two subjects in the control group (p<0.05). The most significant improvements were seen in SPI, jitter, and PPQ following voice therapy, which was found to be effective in 19 patients.
Conclusion: Our findings showed a close relationship between MTD type 1 and SPI. Voice therapy improves parameters of amplitude and frequency perturbations, in particular SPI.