Diffusion Tensor Imaging and Reading Disabilities

Principal Investigator: Martha Denckla

We intend to test the hypothesis that DTI parameters will reveal abnormalities in fiber bundle architecture in the perisylvian region of children with RD, and that these DTI changes will be correlated with the presence and severity of RD. The study includes children with RD and FSIQ >80, in the 7-14 years range, who are age/gender-matched to normal controls. Subjects will be called back and offered the opportunity for participation in accordance with HIPAA guidelines. Children were eligible for the RD group if they obtained a score at the 25th percentile or below on the average of Letter Word Identification and Word Attack subtests from the Woodcock Johnson (WJ-III). Children were eligible for the control group if they obtained a score at the 40th percentile or above on the average of the Letter Word Identification and Word Attack subtests from the WJ-III.

DTI data was acquired using a single-shot EPI with SENSE sequence, which yields 45 2.5 mm isotropic in-plane resolution axial covering the entire brain. We intend to quantify by voxel-based analyses both basic DTI parameters (FA, ADC, coherence index) and white matter architecture (orientation, size, and branching of fiber bundles) in the perisylvian region. We also intend to delineate the arcuate fasciculus component of the superior longitudinal fasciculus (SLF) through DTI fiber tracking. The parameters of reading speed, and related functions, constitute dependent variables for DTI-behavioral correlational analyses that will follow group comparisons (RD vs. controls) of DTI parameters. Children participated in neuropsychological testing for approximately 1.5 hours. The MRI exam also lasted for approximately 1.5 hours.
At this stage we are continuing to analyze our previously collected data.