Human communication happens predominantly through voice. The larynx is susceptible to injury and disease. Titze (1988) proposed that the energy required to drive small-amplitude oscillation of the vocal folds depends on tissue biomechanical properties. Vocal fold hydration is supposed to promote ideal biomechanical characteristics of vocal fold mucosa, increased efficiency of vocal fold oscillation, and enhance voice quality. There is evidence that, as the body tries to stimulate the thirst center in the hypothalamus; leads to reduced saliva production, resulting in dryness of the mucosa of the mouth and pharynx (Tortora & Grabowski, 1996). As the vocal folds also comprise of mucosa, which is broadly separated into the epithelium …show more content…
The effects of hydration on the human voice include variations in acoustic parameters of perturbation in vocal fold vibration such as reduced jitter and shimmer (Franca, 2006). Vocal jitter is defined as variation of the frequency (number of cycles or events per unit) of successive vocal folds cycles, whereas vocal shimmer is defined as short-term (cycle-to cycle) variability in vocal fold vibration amplitude (Titze, 1994). Jitter and shimmer are indicators of vocal fold vibration perturbation that draw a parallel with perceptual indications of voice quality (Martens, Versnel, & Dejonckere, 2007; Ng, Wong, Wei, Wong, & Lam, 2008; Yiu, Murdoc, Hird, & Lau, 2002). Ryu et al. (2004) and Groves-Wright (2007) employed the classic measures of jitter, shimmer, NHR, relative average perturbation, voice turbulence index, and spectral tilt of phonation samples to investigate the presence of foreign substances in the larynx can induce change in the acoustical parameters. In recent years, non-linear methods of analysis have been gaining popularity in the study of vocal fold acoustics (Zhang & Jiang et al, …show more content…
Aim of the study
To determine the short - term effects of dehydration (oral breathing) and subsequent rehydration (steam inhalation) on acoustic measures of voice.
Objectives of the study
The objective of the study is to study the changes in voice related to two different conditions: hydration and dehydration.
a. Whether steam inhalation and oral breathing will have an effect on Fundamental frequency (F0) of the voice
b. Whether steam inhalation condition would improve perturbation measures and voice quality measures, consecutive oral breathing decreases perturbation measures and voice quality measures
Hypothesis of the study
It was hypothesized that increased systemic and superficial hydration promotes laryngeal health. Perturbation measures Jitter and Shimmer would decrease post steam inhalation and would increase post oral breathing. Fundamental frequency (F0) would decrease post steam inhalation and increase post oral