Impact of Aberrant Acoustic Properties on the Perception of Sound Quality in Electrolarynx Speech A large percentage of patients who have undergone laryngectomy to treat advanced laryngeal cancer rely on an electrolarynx (EL) to communicate verbally. Although serviceable, EL speech is plagued by shortcomings in both sound quality and intelligibility. This study sought to better quantify the relative contributions of previously identified acoustic abnormalities ... Research Article
Research Article  |   August 01, 2005
Impact of Aberrant Acoustic Properties on the Perception of Sound Quality in Electrolarynx Speech
 
Author Affiliations & Notes
  • Geoffrey S. Meltzner
    Massachusetts Institute of Technology, Cambridge
  • Robert E. Hillman
    Massachusetts General Hospital and Harvard Medical School, Boston
Article Information
Speech, Voice & Prosodic Disorders / Voice Disorders / Hearing & Speech Perception / Acoustics / Speech, Voice & Prosody / Speech / Research Articles
Research Article   |   August 01, 2005
Impact of Aberrant Acoustic Properties on the Perception of Sound Quality in Electrolarynx Speech
Journal of Speech, Language, and Hearing Research, August 2005, Vol. 48, 766-779. doi:10.1044/1092-4388(2005/053)
History: Received May 27, 2004 , Accepted January 14, 2005
 
Journal of Speech, Language, and Hearing Research, August 2005, Vol. 48, 766-779. doi:10.1044/1092-4388(2005/053)
History: Received May 27, 2004; Accepted January 14, 2005
Web of Science® Times Cited: 18

A large percentage of patients who have undergone laryngectomy to treat advanced laryngeal cancer rely on an electrolarynx (EL) to communicate verbally. Although serviceable, EL speech is plagued by shortcomings in both sound quality and intelligibility. This study sought to better quantify the relative contributions of previously identified acoustic abnormalities to the perception of degraded quality in EL speech. Ten normal listeners evaluated the sound quality of EL speech tokens that had been acoustically enhanced by (a) increased low-frequency energy, (b) EL-noise reduction, and (c) fundamental frequency variation to mimic normal pitch intonation in relation to nonenhanced EL speech, normal speech, and normal monotonous speech (fundamental frequency variation removed). In comparing all possible combinations of token pairs, listeners were asked to identify which one of each pair sounded most like normal natural speech, and then to rate on a visual analog scale how different the chosen token was from normal speech. The results indicate that although EL speech can be most improved by removing the EL noise and providing proper pitch information, the resulting quality is still well below that of normal natural speech or even that of monotonous natural speech. This suggests that, in addition to the widely acknowledged acoustic abnormalities examined in this investigation, there are other attributes that contribute significantly to the unnatural quality of EL speech. Such additional factors need to be clearly identified and remedied before EL speech can be made to more closely approximate the sound quality of normal natural speech.

Acknowledgments
This study is based on a thesis completed in partial fulfillment of the requirements for the degree of Doctor of Philosophy by the first author in the Speech and Hearing Biosciences and Technology Program at the Harvard-MIT Division of Health Sciences and Technology. This work was supported by grants from the W.M. Keck Foundation and the Department of Veterans Affairs Division of Rehabilitation Research and Development (Grant No. C3343-2DC). We would like to thank Kenneth Stevens of the Research Laboratory of Electronics at MIT, Tom Quatieri of MIT Lincoln Laboratory, and James Kobler of the Voice and Speech Laboratory for their extensive help and expertise.
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