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The Scientific World Journal
Volume 2014, Article ID 925707, 4 pages
Research Article

Measurement of Voice Onset Time in Maxillectomy Patients

1Clinics for Oral and Maxillofacial Rehabilitation, University Hospital, Faculty of Dentistry Tokyo Medical and Dental University, Yushima 1-5-45, Bunkyo-ku, Tokyo 113-8549, Japan
2Department of Maxillofacial Prosthetics, Maxillofacial Reconstruction and Function, Division of Maxillofacial/Neck Reconstruction, Graduate School, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8549, Japan

Received 1 August 2013; Accepted 7 November 2013; Published 20 January 2014

Academic Editors: S. Minagi and M. Yoneda

Copyright © 2014 Mariko Hattori et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Objective speech evaluation using acoustic measurement is needed for the proper rehabilitation of maxillectomy patients. For digital evaluation of consonants, measurement of voice onset time is one option. However, voice onset time has not been measured in maxillectomy patients as their consonant sound spectra exhibit unique characteristics that make the measurement of voice onset time challenging. In this study, we established criteria for measuring voice onset time in maxillectomy patients for objective speech evaluation. We examined voice onset time for /ka/ and /ta/ in 13 maxillectomy patients by calculating the number of valid measurements of voice onset time out of three trials for each syllable. Wilcoxon’s signed rank test showed that voice onset time measurements were more successful for /ka/ and /ta/ when a prosthesis was used ( , and , , resp.) than when a prosthesis was not used. These results indicate a prosthesis affected voice onset measurement in these patients. Although more research in this area is needed, measurement of voice onset time has the potential to be used to evaluate consonant production in maxillectomy patients wearing a prosthesis.