Voice Impact of a Prolonged Reading Task at two Intensity Levels

The purpose of this study is to evaluate the impact on voice of both duration and intensity level of 2 hours of continuous oral reading. Fifty normophonic women undergo two sessions of voice loading in which the required intensity level of voice varied: 60-65 dB(A) for the first session, and 70-75 dB(A) for the second session. Serial voice quality objective data is obtained every 30 minutes during the oral reading tasks, by use of Multi-Dimensional Voice program (Average fundamental frequency (AvF0), Jitter percent (Jitt), Shimmer percent (Shim), Noise-to-Harmonic Ratio (NHR)). Serial measurements of voice range are also carried out every 30 minutes of the oral reading tasks, by use of the voice range profile. Results indicate that AvF0, lowest frequency of voice range and softest output of phonation rise during prolonged oral reading. On the contrary, Jitt tends to decrease and Shim decreases significantly with the passage of time during the voice loading. NRH does not vary statistically. AvF0 and highest outpout of phonation are the only parameters influenced by the required intensity of oral reading task: they are significantly higher in the 70-75 dB session compared to the 60-65 dB session.