Word Reading Skill and Brain Anatomy in Adult Resilient Readers

1. Word Reading Skill and Brain Anatomy in Adult Resilient Readers Suzanne Welcome1, Christiana M. Leonard2, Laura Halderman1, Stephen Towler2, & Christine Chiarello1 University of California, Riverside1, University of Florida, Gainesville2

2. Biological Substrates for Language Project 200 university students • 7 Divided Visual Field tasks - words presented to left and right hemispheres • Structural MRI • Woodcock Reading Mastery Tests - Revised • Word Identification • Word Attack • Passage Comprehension • Wechsler Abbreviated Scale of Intelligence • Handedness preference and performance

3. * Groups differ significantly (p < 0.01) on this measure

4. Compensation for Poor Phonological Decoding Stanovich (1980) proposed that deficiencies in lower-level processes like phonological decoding can be compensated for by greater reliance on semantic factors like context • Predicts that resilient readers will show normal performance on semantic tasks while showing deficits in other tasks

5. Study Questions • Do resilient readers show behavioral profile consistent with semantic compensation mechanism? • Do resilient readers differ in behavioral asymmetry from proficient readers? • Do resilient readers differ in brain asymmetry or other aspects of brain anatomy from proficient readers? • Do resilient and proficient readers differ in predictors of reading comprehension?

7. DVF Experiments

8. Brain Measures • Gray and matter volume of cerebral hemispheres • Cerebellar volume • Total area and area of sections of corpus callosum • Length and asymmetry measures of language-relevant regions • Planum temporale • Planum parietale • Heschl’s gyrus • Pars triangularis • Pars opercularis

9. DVF Task Results • Standard RVF/LH advantage found in both accuracy and reaction time for all 7 tasks • Reading groups did not differ in asymmetry index for any of the seven experimental tasks in either accuracy or RT • Groups did not differ in RT on any experimental task • Resilient readers less accurate only on tasks that do not require semantic access

10. * * * Pseudoword Naming Word Naming Masked Word Recognition Lexical Decision Verb Generation Category Generation Semantic Decision

11. Anatomical Results • Resilient readers do not differ from proficient readers in any of length, area, volume or asymmetry measures • However, relationship between measures and reading ability differs between groups

12. Predicting Passage Comprehension Scores Proficient Readers White matter volume and verbal IQ account for 66% of variance Resilient Readers White matter volume and verbal IQ account for less than 1% of variance

13. R2 = .002 R2 = .466 R2= .482 R2 = .089

14. Summary and Conclusions • Do resilient readers show behavioral profile consistent with semantic compensation mechanism? • Resilient readers are less accurate only on tasks that do not require semantic access • Do resilient readers differ in behavioral asymmetry from proficient readers? • Resilient readers do not show altered pattern of behavioral asymmetry • Do resilient readers differ in brain asymmetry or other aspects of brain anatomy from proficient readers? • Resilient readers do not differ on any measure of brain anatomy • Do resilient and proficient readers differ in predictors of reading comprehension? • Proficient readers’ comprehension predicted well by brain volume and verbal IQ; resilient readers’ comprehension not well predicted by any measure

15. Thanks!