Date of Award

5-2009

Document Type

Open Access Dissertation

Degree Name

Doctor of Philosophy (PhD)

Degree Program

Communication Disorders

First Advisor

Baran, Jane A.

Second Advisor

Zaretsky, Elena

Third Advisor

Boscardin, Mary Lynn

Subject Categories

Communication Sciences and Disorders | Linguistics

Abstract

Dyslexia is a clinical diagnosis often associated with phonological processing deficits. There are, however, other areas of concern, such as the presence of auditory temporal processing (ATP) disorders. One method of investigating ATP is the gap detection (GD) paradigm. This study investigated GD performance using the Gaps-in-Noise © (GIN) test in three groups of 30 children, aged 8 to 9 years. GD thresholds and gap identification scores (%) were determined for each participant. The three groups of participants included (Group I) children with dyslexia and phonological deficits, (Group II) children with dyslexia and no significant phonological deficits, and (Group III) normal reading peers. Repeated-measures ANOVA showed that GD thresholds for the three groups were significantly different. Group I showed longer GD thresholds (RE, 8.5 msec; LE, 8 msec), than did Group II (4.9 msec for both ears) or Group III (RE, 4.2 msec; LE, 4.3 msec). Close inspection of the threshold values for the three groups revealed that the thresholds for Group II overlapped substantially with those of Group III, but not with those of Group I. Similar trends were also noted for the gap identification analysis. From a clinical perspective, the majority of participants in Group II and all participants in Group III performed within normal limits on both measures (i.e., thresholds and identifications), while performance of participants in Group I fell below established norms on these measures. Finally, additional analyses revealed that ATP was highly correlated with phonological processing measures indicating a relationship between the presence of phonological deficits and ATP deficits. This study confirmed that ATP deficit is a factor to be considered in dyslexia and suggested that the GIN © test is a promising clinical tool that should be incorporated in the evaluation procedures for children with reading difficulties.

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