Neural Drive to Muscles in Stuttering EMG recordings were made from muscles of the jaw, lip, and neck during speech of 10 stutterers and 10 nonstutterers. One-second records of disfluent behaviors of stutterers and of fluent speech of the normal speakers were analyzed by computing cross correlations between all possible muscle pairs and spectra for each ... Research Article
Research Article  |   June 01, 1989
Neural Drive to Muscles in Stuttering
 
Author Affiliations & Notes
  • Anne Smith
    Purdue University
Article Information
Research Articles
Research Article   |   June 01, 1989
Neural Drive to Muscles in Stuttering
Journal of Speech, Language, and Hearing Research, June 1989, Vol. 32, 252-264. doi:10.1044/jshr.3202.252
History: Received September 3, 1987 , Accepted July 26, 1988
 
Journal of Speech, Language, and Hearing Research, June 1989, Vol. 32, 252-264. doi:10.1044/jshr.3202.252
History: Received September 3, 1987; Accepted July 26, 1988

EMG recordings were made from muscles of the jaw, lip, and neck during speech of 10 stutterers and 10 nonstutterers. One-second records of disfluent behaviors of stutterers and of fluent speech of the normal speakers were analyzed by computing cross correlations between all possible muscle pairs and spectra for each muscle channel. The cross correlation analysis indicated that for both the disfluent behavior of stutterers and the fluent speech of nonstutterers, jaw muscles (including antagonistic pairs), lip muscles, and neck muscles tend to be coactivated. Thus, no dramatic differences in muscle activation patterns were revealed in the correlational analysis. In contrast, spectral analysis revealed differences between muscle activity during disfluent behavior and fluent speech. During disfluencies the muscles of 6 of the stutterers showed large, rhythmic oscillations in the frequency range of 5 to 12 Hz. Large oscillations were not observed in this frequency range in the muscle activity of normal speakers. The oscillations in muscle activity during disfluencies generally occurred at the same frequency in the various muscle systems studied. These results suggest that diverse muscles are subject to common oscillatory synaptic drive during disfluent behaviors and that this drive is disruptive to speech production. A reasonable speculation is that the disruptive oscillatory drive is produced by tremorogenic mechanisms.

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