Yale University School of Medicine An fMRI comparison of reading disabled adolescents with and...
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Transcript of Yale University School of Medicine An fMRI comparison of reading disabled adolescents with and...
Yale University School of Medicine
An fMRI comparison of reading disabled adolescents with and without general cognitive difficultyNicole Landi1,2,3, Stephen J. Frost3, W. Einar Mencl3, Rebecca Sandak3 & Kenneth R. Pugh2,3
1Yale Child Study Center; 2Yale University Scool of Medicine & 3Haskins Laboratories
Background
Neurobiological circuit associated with skilled reading:
TASKS
Behavioral assessments:
-Woodcock-Johnson III Tests of Achievement (WJ; Woodcock, McGrew, & Mather, 2001)-Tests of Word Reading Efficiency (TOWRE; Torgesen, Wagner & Rashotte, 1999)-Comprehensive Test of Phonological Processing (CTOPP; Wagner, Torgesen, & Rashotte, 1999)-Peabody Picture Vocabulary Test (PPVT; Dunn & Dunn, 1997)-Wechsler Abbreviated Scale of Intelligence (WASI; The Psychological Corporation, 1999).
fMRI task:
Event-related fMRI: match/mismatch judgment via button press to auditorally and visually presented targets to a picture cue
Mismatched targets include: Printed: words, pseudowords, consonant strings, semantically related words & Spoken: words, pseudowords
Study Methods
fMRI Data Acquisition and Analysis
Study Results: Behavioral data fMRI Results:RD-D fMRI Results: RD-AParticipantsFull sample:25 RD children, 13 RD-D, 12 RD-AAge M = 8.2 yearsfMRI Sample:7 RD children, 5, RD-D, 2RD-A
ALL RD > 90 SS on reading composite (WJ Spelling, Word Attack and passage comprehension)RD-D > 90 on WASI performance IQ RD-A >90 on WASI peformance IQ
Funding was provided by NICHD R03 HD053409, Landi (PI) & NICHD RO1 HD 048830 Pugh (PI)
We acquired functional images on a Siemens 1.5T Sonata MRI scanner at the Yale University School of Medicine. Subjects recieved 40 trials of each condition across 10 scan runs. Subject activations to the base stimulus conditions were analyzed across subjects with ANOVA.
IFG MTG/ITG
OT/VWFA
SMG/STG
AG
Individuals with reading disability (RD) show less activation in the posterior left hemisphere (LH) reading circuit relative to typically developing readers across a variety of reading tasks (e.g., Pugh et al. 2000)
•A substantial number of individuals with RD do not meet formal discrepancy criteria.
•Many RD readers also have difficulty in one or more other academic skill domains. In the current study, we explore the question of functional subtypes in RD, examining:
•Reading disability with achievement discrepancy (RD-D)
•Reading disability with poor general achievement (RD-A).
We ask: What are the behavioral and neurobiological markers associated with with RD-A vs. RD-D?
time
RD-A - RD-D, printed words RD-A- RD-D, spoken words
Yellow = RD-A> RD-D; Purple = RD-D>RD-A p = .005, FDR correcte; slice numbers = MNI Z coordinates
LL
PIQ RD-A < RD-D, p <.01; Reading RD-D = RD-A
ConclusionsBehavior:
RD-D and RD-A have comparable performance on many measures of reading and other academic skills. They differ significantly only on measures of IQ and vocabulary.
fMRI:
For print, RD-A children recruit the parahippocampal region suggesting greater reliance on general memory function for reading. RD-D show greater bilateral temporal activity (STG/MTG), as well as several other RH regions suggesting possible use of semantics to compensate for poor phonological/decoding skills.
For spoken words, RD-A children show greater activation in STG relative to RD-D, suggesting that auditory- lexical connections maybe weaker for RD-A children.
We also observed greater activity in the occipitotemporal (OT) region for the RD-A group for both modalities; this area is typically underactivated in RD children relative to TD children. This suggests that this part of the LH reading circuit is more intact in RD-A children relative to RD-D children.
The only significant difference we observed was for PPVT performance; RD-D >RD A, p = .02
LH OT
bilateralSTG/MTG
Parahippocampal gyrus
Anterior cingulate
STG/ Wernicke’s
LH STG/MTG
RH IFG
bilateralSTG
RH extrastriate & Posterior cingulate
0
20
40
60
80
100
120
PIQ Reading composite
standardized scores
RD-A
RD-D
*
0
20
40
60
80
100
120
Spelling Comprehension PA PPVT TOWRE Applied Problems
standardized scores
RD-ARD-D
*
Identification of RD-A and RD-D
Subtests of reading and academic skills