ERIC Number: EJ1059975
Record Type: Journal
Publication Date: 2015-Apr
Abstractor: As Provided
Reference Count: N/A
Feedforward and Feedback Control in Apraxia of Speech: Effects of Noise Masking on Vowel Production
Maas, Edwin; Mailend, Marja-Liisa; Guenther, Frank H.
Journal of Speech, Language, and Hearing Research, v58 n2 p185-200 Apr 2015
Purpose: This study was designed to test two hypotheses about apraxia of speech (AOS) derived from the Directions Into Velocities of Articulators (DIVA) model (Guenther et al., 2006): the feedforward system deficit hypothesis and the feedback system deficit hypothesis. Method: The authors used noise masking to minimize auditory feedback during speech. Six speakers with AOS and aphasia, 4 with aphasia without AOS, and 2 groups of speakers without impairment (younger and older adults) participated. Acoustic measures of vowel contrast, variability, and duration were analyzed. Results: Younger, but not older, speakers without impairment showed significantly reduced vowel contrast with noise masking. Relative to older controls, the AOS group showed longer vowel durations overall (regardless of masking condition) and a greater reduction in vowel contrast under masking conditions. There were no significant differences in variability. Three of the 6 speakers with AOS demonstrated the group pattern. Speakers with aphasia without AOS did not differ from controls in contrast, duration, or variability. Conclusion: The greater reduction in vowel contrast with masking noise for the AOS group is consistent with the feedforward system deficit hypothesis but not with the feedback system deficit hypothesis; however, effects were small and not present in all individual speakers with AOS. Theoretical implications and alternative interpretations of these findings are discussed.
Descriptors: Speech Impairments, Articulation (Speech), Hypothesis Testing, Feedback (Response), Auditory Stimuli, Aphasia, Acoustics, Vowels, Age Differences, Comparative Analysis, Neurological Impairments
American Speech-Language-Hearing Association (ASHA). 10801 Rockville Pike, Rockville, MD 20852. Tel: 800-638-8255; Fax: 301-571-0457; e-mail: email@example.com; Web site: http://jslhr.asha.org
Publication Type: Journal Articles; Reports - Research
Education Level: N/A
Sponsor: National Institutes of Health (DHHS)
Authoring Institution: N/A
IES Grant or Contract Numbers: R01 DC007683|R01 DC002852