Klaske van Sluis

General discussion 151 Intelligibility issues in tracheoesophageal speech In Chapter 4 we investigated the intelligibility issues in tracheoesophageal speech by exploring acoustic features. This dedicated acoustic study consists of a within-subjects study design in which participants are studied pre- and post- surgery. The study shows that the acoustic contrast is reduced after surgery, with the features of the word-initial, voiced, /d/, becoming more like, unvoiced, /t/. The presence of prevoicing decreases and the burst-duration of this initial consonant increases. Thus, the difference between word-initial /d/ and /t/ be- comes smaller after treatment, which explains a part of the intelligibility issues which occur in this patient population. With the dataset created with our prospective study, valuable speech data including pre- and post-laryngectomy recordings are obtained. This can help future work to further investigate in- telligibility issues, as well as develop clinical applications and interventions to enhance understand ability of tracheoesophageal speech. Long-term stability of tracheoesophageal speech In Chapter 5 we assessed long-term speech outcomes for tracheoesophageal speech. With the ongoing improvements in long-term oncological treatment, survival rates increase. Therefore, patients who have undergone total laryn- gectomy have to speak a substantial number of years with tracheoesophageal speech. The study on long-term voice outcomes of tracheoesophageal speakers in chapter 5 shows the long-term stability of this type of speech. On average, a slight decrease in voice quality and intelligibility is seen after a follow -up 7 to 8 years after total laryngectomy, however some participants showed better voice quality and intelligibility outcomes on the long-term. The general slight decrease of voice quality and intelligibility might be the effect of aging factors. A lot remains to be learned about the impact of aging on voice quality and the (details about) physiological changes of the PE-segment for total laryngectomy patients. With the general increased age expectancy, there can also be co-morbidities in total laryngectomy patients, which affect speaking as well. All morbidities which affect general fitness, pulmonary functioning, or posture are likely to influence the capability of the laryngectomized person to use tracheoesophageal speech. 9.1.2 Measuring voice and speech outcomes after total laryngectomy To adequately measure and monitor voice and speech outcomes following total laryngectomy, assessment tools are needed. We will discuss the instruments used in the various studies which are included in this thesis, their usability, reliability and validity in evaluating speech after total laryngectomy.