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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
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
Biological Substrates for Language Project
Resilient Readers
(n=16)
Proficient Readers (n=16)
Word Attack* 18
(10-25)
61
(46-76)
Passage Comprehension 64
(45-91)
74
(53-94)
Word Identification* 39
(18-60)
56
(30-74)
Verbal IQ 68
(37-96)
70
(37-99)
Performance IQ 66
(32-86)
68
(27-86)
Sex 9 male 9 male
Handedness 11 Right-Handed 12 Right-Handed
* Groups differ significantly (p < 0.01) on this measure
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
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?
DVF ExperimentsPseudoword Naming Pronounce pseudowords created by
changing single letter of word
Word Naming Say presented word
Masked Word Recognition 2-alternative forced choice of word immediately preceded and followed by mask (@/@/@)
Lexical Decision Word/Pseudoword response made by key press
Category Member Generation
Say an example of presented category
(FRUIT – apple)
Verb Generation Say an action associated with presented noun (SCISSORS – cut)
Semantic Decision Natural/Manmade response made by key press
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
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
*
*
*
Pseudoword Naming
Word Naming
Lexical Decision
MaskedWord Recognition
VerbGeneration
CategoryGeneration
Semantic Decision
• 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
Anatomical Results
Semi-partial r2 Beta t-value Signif.
SES .0214 -.169 -0.90 NS
Handedness .0136 .176 0.72 NS
Verbal IQ .1952 .488 2.73 .023
Planum Temporale Asym.
.0308 .226 1.09 NS
Left pars opercularis length
.0234 -.185 -0.95 NS
White Matter Volume .1860 .490 2.67 .026
Predicting Passage Comprehension Scores
Proficient Readers
Resilient Readers
White matter volume and verbal IQ account for 66% of variance
White matter volume and verbal IQ account for less than 1% of variance
Semi-partial r2 Beta t-value Signif.
SES .0014 -.042 -0.13 NS
Handedness .0065 .325 0.88 NS
Verbal IQ .0212 .301 0.50 NS
Planum Temporale Asym.
.0023 -.111 -0.16 NS
Left pars opercularis length
.1072 -.414 -1.12 NS
White Matter Volume .0030 .077 0.19 NS
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