Slide Slam D6
Phonology, Semantics, and Speech Production Abilities Predict Naming, Reading, and Spelling in Individuals with Aphasia/Alexia/Agraphia
Pelagie Beeson1, Kindle Rising1, Alyssa Sachs1, Katlyn Nickels1, Steven Rapcsak1; 1University of Arizona
INTRODUCTION: It has been more than twenty years since the idea was put forth that acquired language impairment can be conceptualized as a reflection of interactive processing of primary systems (e.g., semantics, phonology, and visual processing), rather than a collection of task-specific difficulties with speaking, listening, reading, and writing. In this study, we re-visit the predictive value of a primary systems approach to characterize acquired language impairment in a cohort of individuals with damage to left perisylvian cortical regions. Distinct from previous research, we examined three language modalities (spoken naming, oral reading, written spelling) within one cohort taking into account peripheral abilities (e.g., speech production and handwriting). METHODS: We examined data from a comprehensive assessment of 47 individuals with demonstrated acquired language impairment (aphasia/alexia/agraphia) in relation to age-matched controls, determining the status of Central Language Processes: Phonological awareness/manipulation with words/nonwords including segmentation, deletion, blending, and substitution tasks; Semantic processing including Pyramids & Palm Trees (picture) and PALPA subtests for spoken-word to picture match, written-word to picture match, auditory synonym judgement. Peripheral Processes were tested using: Speech production estimated from word/nonword spoken repetition; Writing (letter selection and production) estimated using upper-lowercase transcoding. Dependent measures included: Boston Naming Test; Oral reading of single words; Written spelling of single words. Statistical analysis: Individual scores on the tasks probing central and peripheral skills were entered into factor analysis using varimax rotation. Resulting factor scores were entered into multiple regression analyses to examine the predictive value of factor scores on dependent measures. To support clinical application, performance on selected individual tests were also analyzed as proxy scores in place of factor scores. RESULTS: Principal component analysis yielded a four-factor solution accounting for 79% of the variance. Factors were easily identified as relating to phonological processing, semantic knowledge, speech production, and letter shape knowledge. Derived factor scores for each participant were entered into multiple regression models to predict oral naming, reading, and written spelling; letter-shape factor was added for writing only. Three factor scores (phonology, semantics, and speech production) accounted for 72.5%, 73.6%, and 61.1% of the variance in naming, oral reading, and single-word writing, respectively, and all made significant contributions to the model. Letter-shape knowledge was not a significant predictor of single word spelling. Individual test scores provided excellent proxy for the factor scores as follows: phoneme deletion for phonological skill, written word to picture matching for semantics, and repetition of single words for speech production. CONCLUSION: This study confirmed the strong predictive association between underlying phonological and semantic skills on naming, oral reading, and spelling, but also separated the contribution of speech production difficulties. For naming and oral reading, speech production abilities had a strong moderating effect on performance, but the status of central phonological abilities had a distinct and marked influence as well. Regarding written spelling, reliance on underlying phonological skills was even more marked. From a clinical perspective, these findings suggest that remediation of the core phonological impairment should be a focused component of treatment for spoken and written language.