Parameters acoustic and high-speed kymography identified effects of voiced vibration and vocal fry exercises

To identify the immediate effects of voiced vibration and vocal fry exercises on healthy subjects by means of acoustic parameters and high-speed kymography.

Thirty healthy subjects (18 women and 12 men, aged from 19 to 45 years old) participated in this study. The voices were recorded at the range of 44.100 samples/second, before and after of the vocal exercises. We developed a computational routine to extract jitter and shimmer. High-speed kymography was generated from laryngeal images for the analysis of the phase times: closed (CPh), open (OPh), of closing (cPh) and of opening (oPh) and used the paired t-Student test and the Mann-Whitney test, with a significance level of 0.05.

After voiced vibrations, acoustic parameters showed reduced jitter for both genders (p=0.018 for men and p<0.01 for women) and reduced shimmer for female voices (p<0.01). There was a decrease in CPh (p=0.046) and cPh (p=0.026) and an increase in OPh (p=0.05) in female vocal folds. After vocal fry, we identified decreased jitter (p<0.01) in female voices and cPh (p=0.026) in male vocal folds.

We observed more positive immediate effects of the voiced vibrations, mainly in voice quality and vocal folds among females. Nevertheless, studies with larger male sample and investigation of the appropriate time of vocal fry are necessary to confirm the results of this search.