Phonatory function under whole-body vibration in different vibratory frequencies and intensities

Abstract

This study investigated phonatory function under whole-body vibration (WBV) in different frequencies and intensities. Twenty non-dysphonic adult volunteers and 2 additional volunteers for the pilot study were recruited for the study. They were exposed to a series of two vibrations: a "test" vibration and a "reference" vibration (set at 10 Hz, 25%) with a 2-s interval in between. The test vibration stimuli were set at 9 vibratory intensities (10% to 50% which varied in 5% steps) and 5 frequencies (5 Hz, 10 Hz, 15 Hz, 20 Hz, 25 Hz) combinations. Perceptual ratings of vibratory magnitude of the larynx and phonatory shakiness were rated using direct magnitude estimation (DME) scaling procedure. A 2 way repeated measures ANCOVA with body mass index (BMI) as a covariate revealed a significant effect of vibratory intensity, but not frequency, on the perceptual rating of phonatory shakiness. The present study revealed that greater phonatory shakiness was perceived at higher intensity level. However, another 2 way repeated measures ANCOVA with BMI as a covariate revealed no significant effect of vibratory intensity and frequency on perceived vibratory magnitude of the larynx.