Basics of Voice Disorders

The chapter starts with the traditional definition of voice disorders based on main symptoms (hoarseness, limited laryngeal efficiency or vocal endurance, sensations of laryngeal discomfort) and systematic aetiological classification (organic-functional), whereas for ‘functional’, the alternative term ‘malregulative’ is recommended. Relevant parameters of voice production are presented in terms of a clinical and an acoustical setting as a basis for a plausible terminology. The long-lasting controversial discussion on vocal registers is objectified by associating subjective sensations and metaphorical interpretations with underlying mechanisms and typical physiological correlates. Another special view refers to the role of the external laryngeal muscles in voice production. Exact epidemiological data about specific types of voice disorders are still rare. Voice disorders are common in all age groups and in both sexes, with one third of the general population said to experience a voice problem once in their lifetime. The higher the voice load, the higher is the risk of developing a voice problem. An overview of pathology and pathogenesis of dysphonia focuses on malformations, inflammation, systemic diseases, malignancies and traumata affecting the larynx, resonance disorders and presbylaryngis. Current knowledge about the genetics of voice disorders is presented, covering vocal fold microstructure, vocal fold diseases, voice-related genetic syndromes and genetic neurological diseases. The genetic treatment approaches include tissue engineering, the use of technology tools and personalised medicine. A final section on the pathophysiology of voice production concentrates on manifestations such as hoarseness, roughness and breathiness, as well as on the influences of subglottal pressure, transglottal airflow and the supraglottal part of the vocal tract.