Differences on Voice Acoustic Parameters between Colombian College Professors with and without Vocal Fatigue

Abstract

To determine which acoustic parameters may be associated with vocal fatigue among college professors in Bogotá-Colombia. This was a cross-sectional study including 27 voice samples of college professors. A gender analysis showed that mean fundamental frequency increased significantly among men and women who reported vocal fatigue compared with the those without fatigue (138.2Hz vs 122.3Hz for males; and 228.7Hz vs 188.9Hz for females; Mann-Whitney U test P value <0.01). Participants with vocal fatigue demonstrated a significantly decreased standard deviation of vocal sound pressure level compared to participants without vocal fatigue (8.7 dB vs 10.2 dB; Mann-Whitney U test P value <0.01). For the males in our sample, fundamental frequency had fair discriminatory value for vocal fatigue (area under the curve=0.7). Sensitivity and specificity were moderate at a cut-off of 125 Hz (0.7 and 0.6 respectively). For females in this sample, the discriminatory value of fundamental frequency was slightly higher (area under the curve=0.8). At a cut-off of 200 Hz, sensitivity was high (0.9) and specificity were moderate (0.7). In conclusion, the fundamental frequencies and standard deviations of vocal sound pressure level are good indicators of and may be used to identify college professors with vocal fatigue. Clinically, voice clinicians may aim to train their clients to produce speech with a higher variation of "intensity" in order to avoid vocal fatigue.