Efeitos da sobrecarga vocal em vozes saudáveis : um estudo sobre sinais videolaringoestroboscópicos e sintomas clínicos da fadiga vocal

Abstract

Introduction: Vocal fatigue (VF) is a limiting phenomenon for speakers that can manifest in various ways. There is no consensus on the parameters that can characterize VF, making it difficult to define because many factors, such as self-reported symptoms, clinical signs observed in the voice and/or laryngeal physiology, and instrumental measurements, can be criteria for its determination. Currently, VF is seen as a complex construct, combining the clinician's perception with the patient's perception. Studies aiming to evaluate laryngeal signs of VF suggest that exposure to prolonged vocal demands can result in laryngeal alterations and patient-reported fatigue. Identifying these signs can help in the clinical diagnosis of VF and prevent the development of potential structural changes in the larynx. Objective: To investigate the effects of vocal overload on healthy voices, characterize videolaryngostroboscopy signs of vocal fatigue, and analyze their association with vocal fatigue symptoms. Method: This is a cross-sectional, descriptive, explanatory, and quantitative study developed in two stages. In the first stage, a snowball sampling method was used to select the panel of experts, and the Delphi technique was employed to achieve consensus on videolaryngostroboscopy parameters indicative of vocal fatigue. A sequence of meetings and online questionnaires was conducted to select parameters, resulting in a consensus on recommendations for otorhinolaryngological evaluation of vocal fatigue. In the second stage, adult individuals without voice complaints and without structural or functional laryngeal alterations underwent a vocal overload activity, characterized by reading texts at a high vocal intensity for ninety minutes. Videolaryngostroboscopy examinations were performed before and after the vocal overload activity. Self-assessment questionnaires were also applied to analyze participants' perceptions of fatigue, effort, and the quality of their vocal production in relation to their own voice. The exams were evaluated by experienced otorhinolaryngologists in a blinded and consensual manner, based on the parameters of an initially constructed protocol. Results: The results revealed a consensus greater than 80.0% for a set of items consisting of tasks and relevant parameters for otorhinolaryngological evaluation of vocal fatigue using videolaryngostroboscopy examination. These items composed a structured protocol recommended for clinical otorhinolaryngologists in the evaluation of patients with suspected vocal fatigue or those exposed to high vocal demands. In the second stage of the study, regarding the experiment involving high vocal load activity, the blinded judgment by expert evaluators indicated differences between pre- and post-overload samples, with 66.7% of cases showing a worsening of the post-activity examination. Among the evaluated parameters, statistical significance was found only for the assessment of glottic closure patterns and the increased proportion of glottic gaps after the vocal load activity. In the self-assessment of fatigue symptoms, effort, and worsening of vocal production quality, all self-assessment instruments showed deterioration: the Visual Analog Scale for Vocal Fatigue (VAS-VF), the Borg CR10 Scale, and the Self-Perception Scale of Vocal Production Quality (SPSVPQ) after the vocal overload activity. However, this perceived worsening was not associated with the deterioration of visual laryngeal examination parameters. Conclusion: The consensus obtained during the study, regarding the parameters and evaluation methodology, provides an important foundation for future clinical application in the diagnosis and management of vocal fatigue. Most patients showed qualitative worsening in videolaryngostroboscopy examinations after the vocal overload activity. However, this finding was not directly related to the patients' perceived symptom worsening. Finally, patient perception proved important for monitoring and clinical diagnosis of vocal fatigue, contributing to the prevention of structural laryngeal changes and highlighting the complexity of VF, which involves both objective and subjective signs.