The impact and application exercises on vocal fatigue

To investigate the therapeutic efficacy and application of different straw phonation exercise regimens as interventions for vocal fatigue in vocally healthy adults under simulated occupational vocal loading conditions. One hundred and fourteen vocally healthy adults aged 20-40 years with no organic lesions confirmed by fibrolaryngoscope examination were randomly assigned into the following groups: (1) control group, (2) Experimental Group A, and (3) Experimental Group B. Immediately following a one-hour vocal loading task (VLT), intervention was provided to all three groups. The control group underwent a 10-minute vocal rest, Experimental Group A performed a 10-minute straw phonation exercise, and Experimental Group B performed a 5-minute straw phonation exercise after a 5-minute vocal rest. Straw phonation consisted of sustained vowel /u:/ phonation through a straw (inner diameter: 5 mm; length: 19.5 cm), performed continuously for the assigned duration. Acoustic parameters including maximum phonation time (MPT), Fundamental frequency (F0), jitter, shimmer, harmonic-to-noise ratio (HNR) and cepstral peak prominence for speech (CPP-s) and perceptual voice assessment including Vocal Tract Discomfort (VTD) and Perceived Phonatory Effort (PPE) were performed before VLT (T0), immediately after VLT (T1), and post-intervention (T2). Data were analyzed using generalized estimating equations (GEE) to evaluate time, group, and time × group interaction effects. For acoustic voice measures, no significant changes were observed at T2 compared with T1 in the control group. Experimental Group A exhibited significant changes in MPT, F0, jitter and CPP-s at T2 compared with T1, whereas Experimental Group B demonstrated significant changes in MPT, jitter, shimmer and HNR at T2 compared with T1 (p < 0.05). No differences were observed among the three groups at T0. At T2, Experimental Group B showed superior jitter, shimmer, HNR, and CPP-s values compared with the control group, while Experimental Group A had higher CPP-s values than the control group. Additionally, Experimental Group B had higher HNR compared with Experimental Group A . For subjective voice measures, both Experimental Groups A and B outperformed the control group in the VTD (lump in the throat) and PPE scores at T2, and Experimental Group A had higher scores of VTD (Total) than Experimental Group B. Straw phonation produced greater short-term improvements than vocal rest alone in acoustic and subjective voice measures. After prolonged vocal use, a 5-minute vocal rest followed by 5-minute straw phonation yielded greater immediate voice quality improvements and reduced vocal tract discomfort compared with 10-minute straw phonation training, illustrating the importance of timing in the clinical application of straw phonation after prolonged phonatory loading tasks as indicated by objective and subjective voice measures.Trial registration: This study was registered in the Ethics Committee of the Third Xiangya Hospital of Central South University (Protocol no. 24508) on 2024-06-14, and approved by the Chinese Clinical Trial Registry (ChiCTR2400087198) on 2024-07-22. This trial record can be accessed on the official ChiCTR website https://www.chictr.org.cn/bin/project/edit?pid=232,332.