Klaske van Sluis

162 9.1. English summary outcome, none of the three substitute voice groups reported evidently better outcomes; all speaker groups report a degree of voice handicap. We conclude that tracheoesophageal speech is the favorable speech rehabilitation method ac- cording to acoustic and perceptual outcomes. The study emphasizes the need for standardized measurement tools for systematic evaluations of substitute voice speakers. In Chapter 3 entails a study in which we have prospectively assessed the course of voice outcomes in total laryngectomy patients from before surgery up to one year post-surgery. Patients who were admitted to total laryngectomy were approached to participate. Data is collected over five hospitals situated in The Netherlands and Australia. The study contained four time-points for each participant: prior to total laryngectomy, three months, six months, and twelve months post-surgery. Our study assessments included perceptual evaluation, voice recordings, and self-reported outcomes. The Voice Handicap Index 10 item version (VHI-10) is used for self-reported outcomes. The Acoustic Voice Quality Index (AVQI) is used for acoustic evaluation, AVQI score combines several acoustic measures in one score. Forty-three participants were included in the study, of which 93% received a voice prosthesis. Nevertheless, satisfactory voice rehabilitation with tracheoesophageal speech was not accomplished in all cases, mostly as a result of medical complications. Thirty percent of the participants deceased within the first year after surgery. For the total group, after surgery, a worsening of all voice related values is seen, which gradually improves over time up to one year post surgery. When outcomes for the multidimensional assessment methods assessed over time are pooled, strong correlations are found between the dimensions of voice related outcomes. Worst quality of life score was reported before surgery, after surgery this score gradually improved towards the reference value of healthy people in the same age group. In self-reported voice handicap and quality of life, a response shift was seen, indicating a change in internal standards, values, and meaning of quality of life. We present a detailed acoustic study investigating the changes of the word initial consonants /t/ and /d/ in Dutch speaking individuals before and after total laryngectomy in Chapter 4 . Speech recordings of seventeen participants before and after total laryngectomy are used. Participants did read aloud a Dutch text of neutral content, Tachtig dappere fietsers (’eighty brave cyclists’). This text contained eighteen tokens with /t/ or /d/ in initial position. For each token prevoicing, burst duration and duration of the vowel following the word initial consonant was analyzed. The results show that the acoustic contrast of the /t/ and /d/ in word initial position is reduced after total laryngectomy. In tracheoesophageal speech, the presence of prevoicing of /d/ decreases, and burst duration increases. In the post-operative situation, therefore, /d/ be- comes more similar to /t/ acoustically. For clinical practice, special attention towards intelligibility issues is recommended to enhance understandability of tracheaesophageal speech. Chapter 5 presents the outcomes of longitudinal collected voice record- ings. We assessed differences in voice quality and intelligibility of thirtheen