Acoustic-Phonetic Contrasts and Intelligibility in the Dysarthria Associated With Mixed Cerebral Palsy This study evaluated the relationship between specific acoustic features of speech and perceptual judgments of word intelligibility of adults with cerebral palsy-dysarthria. Use of a contrasting word task allowed for intelligibility analysis and correlated acoustic analysis according to specified spectral and temporal features. Selected phonemic contrasts included syllable-initial voicing; syllable-final ... Research Article
Research Article  |   April 01, 1992
Acoustic-Phonetic Contrasts and Intelligibility in the Dysarthria Associated With Mixed Cerebral Palsy
 
Author Affiliations & Notes
  • Beth M. Ansel
    Purdue University
  • Raymond D. Kent
    University of Wisconsin-Madison
  • Currently affiliated with the Division of Communication Sciences and Disorders, National Institute on Deafness and Other Communication Disorders, NIH. Rockville. MD.
    Currently affiliated with the Division of Communication Sciences and Disorders, National Institute on Deafness and Other Communication Disorders, NIH. Rockville. MD.×
Article Information
Speech, Voice & Prosodic Disorders / Dysarthria / Hearing & Speech Perception / Acoustics / Special Populations / Genetic & Congenital Disorders / Speech, Voice & Prosody / Speech / Research Articles
Research Article   |   April 01, 1992
Acoustic-Phonetic Contrasts and Intelligibility in the Dysarthria Associated With Mixed Cerebral Palsy
Journal of Speech, Language, and Hearing Research, April 1992, Vol. 35, 296-308. doi:10.1044/jshr.3502.296
History: Received January 30, 1991 , Accepted August 5, 1991
 
Journal of Speech, Language, and Hearing Research, April 1992, Vol. 35, 296-308. doi:10.1044/jshr.3502.296
History: Received January 30, 1991; Accepted August 5, 1991

This study evaluated the relationship between specific acoustic features of speech and perceptual judgments of word intelligibility of adults with cerebral palsy-dysarthria. Use of a contrasting word task allowed for intelligibility analysis and correlated acoustic analysis according to specified spectral and temporal features. Selected phonemic contrasts included syllable-initial voicing; syllable-final voicing; stop-nasal; fricative-affricate; front-back, high-low, and tense-lax vowels. Speech materials included a set of CVC stimulus words.

Acoustic data are reported on vowel duration, formant frequency locations, voice onset times, amplitude rise times, and frication durations. Listeners’ perceptual assessment of intelligibility of the 16 dysarthric adults by transcription and rating tasks is also presented. All but one acoustic contrast was successfully made as evidenced by measured acoustic differences between contrast pairs. However, the generally successful acoustic contrasts stood in marked contrast to the poorly rated intelligibility scores and high error percentages that were ascribed to the opposite pair members.

A second analysis examined the contribution of these acoustic features towards estimates and prediction of intelligibility deficits in speakers with dysarthria. The scaled intelligibility was predicted by multiple regression analysis with 62.6% accuracy by acoustic measures related to one consonant contrast (fricative-affricate) and three vowel contrasts (front-back, high-low, and tense-lax). Other measured contrasts, such as those related to contrast voicing effects and stop-nasal distinctions, did not seem to contribute in a significant way to variability in the intelligibility estimates. These findings are discussed in relation to specific areas of production deficiency that are consistent across different types of dysarthria with cerebral palsy as the etiology.

Acknowledgments
This research is based on a doctoral dissertation conducted at the University of Wisconsin-Madison. Appreciation is extended to those individuals who generously agreed to participate in this study. Special thanks to Dr. Jack Gandour and two anonymous reviewers for their valuable comments and suggestions.
Order a Subscription
Pay Per View
Entire Journal of Speech, Language, and Hearing Research content & archive
24-hour access
This Article
24-hour access