Whole-body vibration as a potential method to improve phonatory function: a passive alternative to vocal function exercise

Abstract

Whole-body vibration as a potential method to improve phonatory function: A passive alternative to vocal function exercise Objective: Whole body vibration (WBV) is the transmission of movement from a mechanical vibration source through the body. Repeated exposure to WBV has been shown to cause neurogenic adaption of the skeletal muscles and to facilitate muscular function improvement, as well as reduced levels of cortisol (Cardinale & Wakeling, 2005). Phonatory function, in terms of intensity, has been found to improve following WBV at around 10 -15 Hz when compared to vibration below 10 Hz (Yokoyama and Hoshino, 1973). The current project investigated the use of WBV as a passive method of improving phonation (minimum/maximum fundamental frequency, maximum vocal intensity) and self-perception of vocal condition compared to traditional vocal function exercise (VFE). Cortisol was measured to provide a biological explanation of changes in the outcome measures. Methods: Forty-five females with healthy voices were randomly assigned to one treatment group: WBV only, VFE, or a combined treatment (WBV+VFE). The WBV group phonated /a/ on a vibrating platform (15 Hz, 2mm amplitude). The VFE group performed vocal exercises without vibration. The WBV+VFE group performed vocal function exercises on the vibrating platform. All groups received a total of ten minutes of training. Results: The VFE group significantly increased their maximum fundamental frequency after the intervention (p<.05), with the WBV group showing the same trend. There was no statistically significant change in vocal intensity or salivary cortisol after treatment across all groups. On the self-rating of vocal condition, the WBV group rated it easier to phonate in the low pitch range after treatment compared to the WBV+VFE group (p < .05). Conclusions: Limited changes were observed across groups on the outcome measures. However, the study suggests that WBV may be worth further exploring, because the WBV showed similar gains in vocal function as the well-documented VFE after only ten minutes of training. Further research is being conducted on the use of WBV with dysphonic adults in a nine session treatment program. References: Cardinale, M., & Wakeling, J. (2005). Whole body vibration exercise: are vibrations good for you? British Journal of Sports Medicine, 39, 585-589. Yokoyama, T., & Hoshino, K. (1973). Effects of whole-body vibration on speech voice intensity and maximum phonation time. Nihon Jibiinkoka Gakkai kaiho, 76 (12), 1414-1425. Retrieved from https://www.jstage.jst.go.jp/browse/jibiinkoka/-char/ja/