The Influence of Speaking Rate on Vowel Space and Speech Intelligibility for Individuals With Amyotrophic Lateral Sclerosis The relationship between speaking rate, vowel space area, and speech intelligibility was studied in a group of 9 subjects with amyotrophic lateral sclerosis (ALS) and 9 age- and gender-matched controls. Subjects read a standard passage (the Farm Passage) at three speaking rates, including HABITUAL, FAST, and SLOW. Vowel segment durations ... Research Article
Research Article  |   October 01, 1995
The Influence of Speaking Rate on Vowel Space and Speech Intelligibility for Individuals With Amyotrophic Lateral Sclerosis
 
Author Notes
  • Currently affiliated with Central Missouri State university, Warrensburg
    Currently affiliated with Central Missouri State university, Warrensburg×
  • Contact author: Greg S. Turner, Department of Speech Pathology and Audiology, Martin 34, Central Missouri State University, Warrensburg, MO 64093–5092.
    Contact author: Greg S. Turner, Department of Speech Pathology and Audiology, Martin 34, Central Missouri State University, Warrensburg, MO 64093–5092.×
Article Information
Speech, Voice & Prosodic Disorders / Speech, Voice & Prosody / Speech / Research Articles
Research Article   |   October 01, 1995
The Influence of Speaking Rate on Vowel Space and Speech Intelligibility for Individuals With Amyotrophic Lateral Sclerosis
Journal of Speech, Language, and Hearing Research, October 1995, Vol. 38, 1001-1013. doi:10.1044/jshr.3805.1001
History: Received November 4, 1994 , Accepted March 27, 1995
 
Journal of Speech, Language, and Hearing Research, October 1995, Vol. 38, 1001-1013. doi:10.1044/jshr.3805.1001
History: Received November 4, 1994; Accepted March 27, 1995

The relationship between speaking rate, vowel space area, and speech intelligibility was studied in a group of 9 subjects with amyotrophic lateral sclerosis (ALS) and 9 age- and gender-matched controls. Subjects read a standard passage (the Farm Passage) at three speaking rates, including HABITUAL, FAST, and SLOW. Vowel segment durations and target formant frequencies were measured at each speaking rate from select words containing the vowels /i/, /æ/, /a/, and /u/. To quantify changes in vowel space area across speaking rate, the area of the vowel quadrilateral was calculated for each speaker at each speaking rate. In addition, intelligibility estimates at each speaking rate were obtained for the dysarthric speakers. Results revealed that dysarthric speakers exhibited smaller vowel space areas and less systematic changes in vowel space as a function of speaking rate, when compared to the neurologically intact speakers. In an examination of the relationship between vowel space area and speech intelligibility, vowel space was found to account for 45% of the variance in speech intelligibility. This result suggests that vowel space area is an important component of global estimates of speech intelligibility.

Acknowledgments
Portions of this study were presented at the Conference on Motor Speech: Motor Speech Disorders and Speech Motor Control, Sedona, Arizona, 1994. We would like to thank the patients and staff of the ALS Clinic at the University Hospital and Clinics in Madison, Wisconsin. Michiko Hashi, Ray Kent, and Mark Leddy made valuable comments on an earlier version of this manuscript. This work was supported by NIH Grant No. DC00319 from the National Institute on Deafness and Other Communication Disorders.
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