Date of Degree


Document Type


Degree Name



Speech-Language-Hearing Sciences


Richard G. Schwartz

Committee Members

Klara Marton

Michelle MacRoy-Higgins

Mary Ann Romski

Subject Categories

Speech Pathology and Audiology


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


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.