Date of Degree

2-2018

Document Type

Dissertation

Degree Name

Ph.D.

Program

Speech-Language-Hearing Sciences

Advisor(s)

Richard G. Schwartz

Committee Members

Klara Marton

Michelle MacRoy-Higgins

Mary Ann Romski

Subject Categories

Speech Pathology and Audiology

Keywords

Cerebral palsy, eye tracking, lexical access, spoken word recognition, augmentative communication

Abstract

This study examined lexical access in adolescents and adults with cerebral palsy and severe speech and physical impairment (CP/SSPI) who have limited language production due to severe dysarthria or anarthria. To date, the impact of a severe speech production deficit on lexical activation and the organization of the mental lexicon has not been investigated. Such an investigation may support or refute these views of an articulatory basis of speech perception and lexical development and access. The hypothesis of this study is that spoken word recognition will be severely reduced or absent in this population although individual differences may result in variations. Method. Using the visual world eye tracking paradigm, in 16 adolescents and adults with CP/SSPI, the study examined resolution of phonological or semantic competition among referents for a spoken word as it unfolds over time. Eye gaze patterns were compared to published data as well as to a group of eight age-matched adults with no neurological impairment and to children with typical development (TD) from a previous study using the same stimuli and experimental design. Results. Participants with CP/SSPI revealed significant fixations to targets and to phonological onset competitors but not to semantic relatives beyond those directed to unrelated pictures while children with TD demonstrated significant phonological and semantic competition effects. The participants with CP/SSPI and higher PPVT-4 scores exhibited eye gaze patterns more similar to adults with no neurological impairment while those with lower scores were less efficient at resolving competition. Conclusion. Despite the presence of a severe speech impairment, individuals with CP/SSPI demonstrated varying levels of lexical activation, suggesting that theories relying on an articulatory bases of speech perception do not offer a complete explanation of lexical development and access in this population.

Share

COinS
 
 

To view the content in your browser, please download Adobe Reader or, alternately,
you may Download the file to your hard drive.

NOTE: The latest versions of Adobe Reader do not support viewing PDF files within Firefox on Mac OS and if you are using a modern (Intel) Mac, there is no official plugin for viewing PDF files within the browser window.