Compensatory articulation was investigated in normal and brain-damaged individuals by comparing vowel production under normal and perturbed speaking conditions. The effects of fixed mandibular positioning on first and second formant frequencies of the vowels (u i ae a) were investigated in ten normal subjects, six nonfluent aphasics and six fluent aphasics. Adaptation to perturbation was examined under compensatory and noncompensatory conditions, in which the degree of mandibular opening posed maximal and minimal interference respectively, with reference to normal articulatory positioning. F1 and F2 values, determined by linear predictive coding, were measured at the onset and midpoint of glottal pulsing to identify changes in compensation over time. Results of statistical analyses indicated variable effects of perturbation in both the normal and aphasic subject groups. Analyses of the data with respect to perceptual difference limens suggested that formant deviations in compensatory and noncompensatory productions of all subjects groups would have resulted in changes in vowel quality. The results were interpreted as indicating that compensatory performance, although evident, was neither complete nor immediate in any of the subject groups tested. Moreover, articulatory reorganization and compensation for fixed mandibular positioning appeared to be preserved in nonfluent and fluent aphasics. The findings are discussed with respect to models of speech motor programming and neurogenic models of speech production.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.22748 |
| Date | January 1995 |
| Creators | Kim, Jean H. |
| Contributors | Baum, Shari R. (advisor) |
| Publisher | McGill University |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Format | application/pdf |
| Coverage | Master of Science (School of Communication Sciences and Disorders.) |
| Rights | All items in eScholarship@McGill are protected by copyright with all rights reserved unless otherwise indicated. |
| Relation | alephsysno: 001453551, proquestno: MM05571, Theses scanned by UMI/ProQuest. |
Page generated in 0.0015 seconds