Date of Award

1989

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Communication Sciences and Disorders

First Advisor

Paul R. Hoffman

Abstract

The present study investigated learning rate differences relative to number of sessions necessary to reach a terminal criterion on /s/ production accuracy by four pre-school functional misarticulators under two different treatment approaches; a sensory motor approach and a cognitive-communicative approach. Phonetic transcriptions of the misarticulator's productions of a forty item word and connected speech generalization probe administered continuously over treatment was used to determine percentage of correct productions. Probe items included /sC-/, /sCV-/, /-Vs/, and /-VCs/ single syllable word shapes. These four and five year old misarticulating subjects who produced stop consonants for (s) were also compared with four normal subjects of the same age in performance on both auditory perceptual measures involving the stop-continuant contrast, and on spectrographic measures of mean duration and variability involving productions of intervocalic /s/ singletons and /s/ clusters. Experimental subjects also produced intervocalic stop consonants for within group duration comparisons with /s/ productions at pre-treatment. Misarticulating subject's performances were compared to normal subject's performances on the /s/ measures at pre-; mid- and post-treatment; and were compared to the normals on the auditory perceptual measures at pre- and post-treatment. Normal subjects were tested only once on the speech production measures and the auditory perceptual measures. Subjects in the Cognitive approach attained a sustained level of accuracy of production of (s) in connected speech earlier than their sensory-motor matches. Other treatment related findings which occurred across all misarticulators included emergence of /-Vs/ syllable shape first; attainment of 75% production accuracy of (s) in single words and connected speech simultaneously on an intrasubject basis. Misarticulators performed similarly to normals on auditory perceptual tasks at pre-treatment, though they differed from normals on the speech production duration measures at all three points in time. The misarticulators at pre-treatment evidenced mean durations which differentiated the three different phonetic contexts sampled, though the differences were imperceptible to adults. These duration differences were interpreted as originating at a cognitive level rather than an exclusively motor level, and appeared to be indicative of early feature level organization of /s/.

Pages

359

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