The vocal clarity of female speech-language pathology students: an exploratory study

Objectives: This study investigated the production of a clear voice in speech pathology students using acoustic and auditory-perceptual analyses.

Study design: A prospective study to evaluate the vocal quality of two groups of speech-language pathology students: first year (N=41) and final year, graduating (N=34) undergraduates was conducted.

Method: Speakers were asked to produce a sustained vowel in two conditions: habitual speaking voice and a "clear" voice, as if they were modeling during voice therapy (performance voice). Acoustic and perceptual analyses were carried out on these voice samples.

Results: There were no differences in distribution of vocal clarity between student cohorts and the voice conditions. The graduating students' voices had significantly less jitter and shimmer than the voices of the beginning students. No significant differences in the acoustic measures were found between the two voice conditions. Clear voices had significantly higher harmonic-to-noise ratio (HNR) and lower jitter (%) and shimmer (%) than unclear voices.

Conclusions: The graduating student SLPs did not produce perceptually clearer voices than the beginning student SLPs. The students' performance voices were not perceptually clearer than their habitual voices. Perceptually clear voice was associated with significantly higher HNR (dB) and lower jitter and shimmer, suggesting that acoustic noise and perturbation contribute to perceptual judgments of vocal clarity.