Acoustic Effects of Vocal Warm-Up: A 7-Week Longitudinal Case Study

A case study was used to determine which acoustic parameters would be sensitive to a SOVT-based vocal warm-up over the duration of a standard voice treatment.

The longitudinal research design consisted of repeated voice measures during 7 weeks from a single subject, a 48-year-old male occupational voice user with a history of voice disorders. A steady phonation and running speech tasks were performed before and after an intensive 1-minute water-resistance voice exercise (WRT). Acoustic assessment of the pre-and postrecordings from each session was obtained with freely accessible software (e.g., Audacity, PRAAT) and acoustic measures (e.g., fundamental frequency, jitter, shimmer, alpha ratio, NHR, HNR, L1L0, Cepstral Peak Prominence smoothed).

After WRT, the analysis indicated that jitter, shimmer, and NHR had a small but statistically significant decrease, while alpha ratio, CPPS, and HNR had a statistically significant increase. For the days where there were six repetitions, there was a larger effect in the later repetitions in the day for some metrics (i.e., alpha ratio, shimmer, NHR, CPPS), while others had the biggest effect in the first two repetitions in a day (i.e., jitter, HNR).

A short vocal water-resistance voice task had a positive effect on the short-term acoustic voice metrics after each repetition of the exercise, independent of the number of repetitions throughout the day. When five repetitions of this exercise routine occurred, there was a more substantial influence on the proportion of acoustic voice changes.