The effect of vibration therapy on the phonatory function of the larynx and thyroid function in female voice professionals

Background
Poor posture, increased muscle tension, gastroesophageal reflux, thyroid problems, hormonal changes, and prolonged stress can all negatively affect voice performance. Among chronic conditions that impact voice quality, thyroid disease is the most commonly cited.

Aim
The aim of this study was to evaluate the effects of vibration therapy on both voice production and thyroid function in female professionals who use their voices extensively.

Material and methods
This study included 48 women diagnosed with functional dysphonia, randomly divided into a study group (n=34) and a control group (n=14). The intervention consisted of three 30-minute sessions per week over a six-week period using the Vitberg Rehabilitation Massager. Assessments included thyroid hormone levels (TSH, fT3, fT4) and Mean Phonation Time (MPT) before and after therapy.

Results
Statistically significant differences were found in the study group for fT3 (pg/ml* ) and TSH (uIU/ml* ) levels after therapy, with mean fT3 levels decreasing from 3.18 (SD±0.36) to 2.96 (SD±0.33) and mean TSH levels showing no significant change. In contrast, the control group showed no significant differences in TSH levels but did exhibit significant changes in fT3 levels. Additionally, the study group demonstrated a significant increase in MPT from 13.17 seconds (SD±2.25) to 15.97 seconds (SD±2.87), while the control group showed a decrease in MPT.

Conclusions
Vibration therapy significantly affected hormone levels (TSH and fT3) and improved MPT in the study group compared to the control group. These findings suggest that vibration therapy may be a beneficial intervention for improving voice quality and thyroid function in female voice professionals.