Voice Type Classification and Aerodynamic Measurements in Professional Singers in Combination with an Analysis of the Morphopathogenesis of Singers’ Nodules as the Most Frequent Vocal Fold Complication. Summary of the Doctoral Thesis

Abstract

In addition, the study developed a novel and practically applicable method for objectively determining vocal voice type, based on the anatomical and aerodynamic characteristics of the upper airway. Sixty professional singers – including opera soloists, university students, and choir artists – were classified into six standard vocal categories. Using digital radiography and spirometry, the volume of the larynx, trachea, and primary bronchi was measured, along with pulmonary vital capacity, peak expiratory flow (PEF), and airflow through different bronchial levels. Each participant’s height and body weight were also recorded. Statistical analysis demonstrated a significant correlation between airway morphology and vocal classification: the larger the laryngeal and tracheobronchial volumes, the lower the associated voice type. A strong association was found between laryngeal volume and PEF values. Singer’s nodules represent one of the most common vocal fold lesions among professional vocalists. Typically arising from prolonged vocal overuse, these lesions are well recognized in clinical practice, yet their underlying biological mechanisms remain incompletely understood. This study provides an in-depth examination of the morphopathological processes involved in the development of singers’ nodules, focusing on cellular proliferation, apoptosis, inflammatory responses, and tissue-specific changes related to the singer’s voice type. The study analysed vocal fold tissue samples from ten female singers with histologically confirmed nodules and compared them with seven control samples from clinically healthy individuals. Immunohistochemical analysis revealed significantly increased expression of Ki-67, TUNEL, EGFR, VEGF, and IL-1? in the nodular tissue, indicating active inflammation and ongoing tissue remodeling. No significant differences in IL-10 or PGP 9.5 expression were observed between groups. Age did not show a statistically significant influence on the morphological changes observed within this sample. By integrating morphological, physiological, and phoniatric perspectives, a practical and applicable method has been developed, contributing to both scientific knowledge and clinical practice. A significant correlation was demonstrated between laryngeal and tracheobronchial volume and vocal type – larger airway volumes were associated with lower vocal types. This finding provides physiological validation for voice classification based on anatomical traits. The developed method, combining digital radiography, spirometry, and anthropometric measurements, proves to be a practical tool for objective vocal type assessment and may support risk evaluation among professional singers. Histological analysis of singer’s nodules revealed active cellular processes in damaged tissue, including increased expression of proliferation, apoptosis, and inflammatory markers. These findings underline the long-term effects of vocal overload on vocal fold structure. Biological markers such as Ki-67, EGFR, VEGF, and IL-1? demonstrate potential as diagnostic indicators for vocal fold strain and could inform future treatment strategies in voice medicine. Vocal type may represent not only a phonetic characteristic but also a predictor of tissue vulnerability, highlighting the need for personalized vocal load management based on individual physiological profiles. Age did not show a statistically significant impact on tissue changes in this study sample, emphasizing the greater importance of vocal load and anatomical variability over chronological age. The findings highlight the importance of interdisciplinary approaches that bridge theoretical knowledge and practical application in preserving and promoting professional voice health. By integrating morphological, physiological, and phonetic methodologies, this study presents a comprehensive perspective on the interaction between voice type and pathological vocal fold changes. The diagnostic framework developed here may serve as a clinical tool for assessing vocal risk and as a preventive resource in professional voice care. These findings make a meaningful contribution to the broader understanding of vocal physiology and the preservation of vocal health among elite voice users. The two components of this study – the development of an objective methodology for voice type determination and the morphofunctional analysis of singers’ nodules, are conceptually interconnected. In this work, voice type is regarded not merely as a phonetic or pedagogical category, but as an anatomically and physiologically determined individual characteristic that influences the biomechanical load of the vocal apparatus. Airway morphology and aerodynamic parameters shape the mechanisms of sound production, whereas prolonged and inappropriate vocal loading relative to an individual’s structural configuration may contribute to the development of pathological alterations in vocal fold tissue resulting in singer’s nodules. Thus, the objective assessment of voice type, combined with analysis of tissue-level biological changes, forms an integrated conceptual framework for understanding professional voice physiology, associated risk factors, and preventive strategies.