Laryngectomee speech in noise—voice effort, speech rate and intelligibility

Different aspects of alaryngeal speech, both esophageal and tracheo-esophageal speech, are being analysed in a joint project between the Department of Speech Communication and Music Acoustics, KTH, and the Department of Logopedics and Phoniatrics, Karolinska Institute. The purpose of the present part of the project was to evaluate the speech performance of laryngectomee speakers while they were reading texts aloud with varying amounts of noise in their ears. The noise consisted of a number of voices in a cacophony. Subjects were four men, two of whom were esophageal speakers, and two tracheo-esophageal speakers. Acoustic speech parameters, such as sound pressure and spectral characteristics, were measured and compared among the subjects. The results showed that the tracheo-esophageal speakers were able to raise their voice level almost as much as normally speaking subjects. The esophageal speakers on the other hand were usually not able to produce as strong voice levels during the text readings. This type of test method with speech in background noise seems promising for assessment of voice effort. In a second part of the present investigation, intelligibility tests were performed. Normally hearing listeners were asked to adjust the level of noise when exposed to the tape-recorded readings of the laryngectomized speakers, the task being to use a high level of noise while still being able to understand the read passage. The result of the intelligibility test revealed that the listeners tolerated a higher degree of noise when listening to the normal speaker than to the alaryngeal speakers. Also, the listeners accepted a little more noise when listening to the tracheo-esophageal speakers than to the esophageal speakers.