An introduction to the assessment of intelligibility of tracheoesophageal speech

In cases of laryngeal cancer, it is sometimes necessary to perform a total laryngectomy. This procedure changes the anatomy and physiology of the vocal tract, with the most noticeable effect on speech. By applying a voice prosthesis, enabling the patient to use tracheoesophageal speech, speech is of better quality than with esophageal or electrolarynx speech, but still very deviant from laryngeal speech. In different countries, studies investigating the intelligibility of speech have been performed. In the Netherlands,only voice quality has been studied in detail. For the understanding of the physiology of the neoglottis and for improving the results of speech therapy it is important to study intelligibility as well. This paper will review relevant literature of research that has been carried out on this subject and will discuss some first acoustical observations in relation to intelligibility.