Summaries of Ph.d. Theses Defended in 2000-2001 Tracheoesophageal Speech. a Multidimensional Assessment of Voice Quality

Annually, approximately 250 total laryngectomies are carried out in the Netherlands. During this surgical procedure, the entire larynx is removed, mostly because of laryngeal or hypopharyngeal cancer. With this removal of the larynx, also the vocal cords are removed, and consequently the natural voice is lost. During a total laryngectomy, caudally, the larynx is separated from the trachea and the remaining tracheal stump is sutured to the skin of the lower neck. This tracheal opening into the neck is called the tracheostoma or plain 'stoma'. Posterior, the larynx is detached from the pharynx. The remaining pharyngeal mucosa and musculature is sutured together in order to re-establish the digestive tract (see also Figures 2.2 and 2.3). In the majority of the laryngectomized patients, voice rehabilitation is nowadays achieved by means of a voice prosthesis. This device is a one-way valve, placed into a fistula between the trachea and the esophagus, allowing air to pass from the trachea into the esophagus and preventing fluids/food from entering the trachea and lungs. The air insufflated into the esophagus causes vibrations of the pharyngoesophageal mucosa and the resulting sound enables tracheoesophageal speech production. The anatomy and morphology of the new voice source (neoglottis) are highly variable: the neoglottis can be situated at different levels in the pharyngoesophageal segment (mostly at the level of the cricopharyngeus muscle and/or the middle and inferior constrictor pharyngeus muscles) and has no uniform anatomical size, shape, or location. The neoglottis also does not have the flexibility and volitional controllability of the glottis. Obviously, the neoglottis plays an important role in tracheoesophageal voice production and its characteristics must influence the quality of the voice. However, at present the knowledge about the relations between the neoglottic characteristics and tracheoesophageal voice quality is still limited.