Pre- and Post-Workday Changes in Acoustic and Aerodynamic Voice Parameters and Vocal Fatigue in Special Education Teachers.

Abstract

Background: Teachers are among the occupational groups at the highest risk for work-related voice disorders due to prolonged and intensive voice use. Although special education teachers face unique occupational demands that may affect vocal health, research examining workday-related voice changes in this population remains limited.

Objective: This study aimed to investigate pre- and post-workday changes in self-reported vocal fatigue and objective voice parameters in special education teachers.

Methods: Thirty-seven special education teachers working in special education and rehabilitation centers participated in this study. Voice assessments were conducted at two time points within the same workday: at the beginning and at the end of the workday. Self-reported vocal fatigue symptoms were assessed using the Vocal Fatigue Index (VFI), and current voice quality was evaluated using a single-item self-rating scale. Acoustic parameters and Cepstral Peak Prominence (CPP) were analyzed using the Praat software. Aerodynamic measures included maximum phonation time and the s/z ratio. Pre- and post-workday differences were analyzed using paired-samples t tests or Wilcoxon signed-rank tests, with false discovery rate adjustment for multiple comparisons.

Results: VFI scores changed significantly at the end of the workday, with increases in all three subscales and the total score (P < 0.05). Participants also reported significantly poorer voice quality in the end-of-day self-ratings (P < 0.05). Acoustic analyses revealed significant increases in fundamental frequency (F0) and CPP at the end of the workday (P < 0.05), although the CPP finding was less consistent after adjustment for selected confounding variables. However, no significant changes were observed in jitter, shimmer, or HNR. Aerodynamic measures did not differ significantly between the two time points. Additional analyses indicated that the observed changes were generally not modified by teaching hours, daily water intake, or smoking status.

Conclusion: Special education teachers reported greater fatigue-related symptoms and physical discomfort by the end of the workday, while also reporting greater perceived improvement in symptoms with voice rest; these findings were accompanied by changes in acoustic measures, including F0 and CPP. These results highlight the importance of evaluating occupational voice use through both subjective and objective measures and emphasize the need for preventive strategies to protect vocal health in special education teachers.