| |
Abstract:
Diffusion tensor imaging (DTI) is a novel magnetic resonance
technique that is currently being used to study white matter
development in child and adult populations (Beaulieu et al, 1999).
Recently regional differences in the myelination of cortical and
subcortical tracts have been studied in normal and learning
disabled adults. As an example white matter anisotropy in the
temporoparietal cortex was found to be significantly correlated
with reading scores in normal and dyslexic adults (Klingberg et
al., 2000) suggesting that reading ability may arise out of
efficiency of communication between cortical areas involved in
visual, auditory and language processing. Preliminary studies
suggest that these findings in adults with dyslexia may also be
useful in the context of other subtypes of learning disabilities
with different corresponding regional white matter anisotropic
correlates. DTI's safety, non-invasiveness, relatively short period
of data acquisition, and advantage that individuals do not have to
perform cognitive tasks makes it suitable for use with young
children. DTI studies need to be extended more widely in children
with specific learning disabilities and correlated with sensitive
and specific neuropsychological measures as well as with school
achievement measures ideally using longitudinal designs.
Methodological issues and future directions surrounding DTI and
learning disabilities will be discussed.
|
