Effects of prolonged loud reading on normal adolescent male voices

The purpose of this article was to test the effects of vocal loading in healthy, peripubescent teenage boys. It was hypothesized that select acoustic measures, ratings of physical appearance of the larynx, and self-ratings of physical effort and vocal quality in the experimental group would significantly change in response to 2 hr of prolonged loud reading.

In this prospective, repeated measures study, 25 boys aged 13-16 years were randomly assigned to either an experimental group (2 hr of continuous loud reading) or a control group (silent reading with brief periods of conversation). Pre-post acoustic, videoendoscopic, and perceptual data including self-ratings were collected. Postreading recovery changes were tracked by monitoring average reading fundamental frequency (F0) and intensity for 20 min following cessation of the reading task.

The experimental group demonstrated statistically significant differences before and after prolonged loud reading for three variables: F0 (p < .01), self-ratings of vocal quality (p < .01), and physical effort (p < .01). No pre-post changes were evident in the control group. In the experimental group, posttest return of F0 to pretest levels occurred within 20 min. Self-ratings revealed that the boys felt that their voice quality worsened and physical effort increased during the experimental task. Expert ratings did not detect any significant differences in either the perceptual quality of the experimental group's voices or their videoendoscopic images.

These findings demonstrate that prolonged loud reading can induce temporary but measurable changes in F0 and in self-perception of vocal function in adolescent males who are experiencing a period of rapid laryngeal growth. The underlying mechanism for these changes remains unclear and warrants continued investigation. Furthermore, the results suggest that in the pubescent male population, comparable vocal loading tasks encountered in daily use should not result in long-term negative effects.