The broad long-term objective of this project is to understand the neural substrates associated with dyslexia (reading and spelling problems), dysgraphia (spelling problems only), and the effect of treatment on brain activation. During the previous grant-period, results were obtained to suggest that dyslexics and control children differ in brain lactate metabolism (i.e., production or clearance of lactate) as measured by proton echo-planar spectroscopic imaging, PEPSI, when performing a phonological task. Also, a specific instructional intervention that improved phonological performance in dyslexic boys were associated with a reduction in brain lactate changes measured during a phonological task.
Specific aim 1 is to develop 5 new language tasks to be used during functional brain imaging for specific aims 2 and 3. Brain activation will be measured using both functional MRI and functional MR spectroscopic imaging (fMRS that uses the PEPSI technique).
Specific Aim 2 is to continue research on differences in brain activation during language tasks between well-characterized dyslexics and age- and IG-matched good readers. The proposed research will extend our prior work by 1) using new language tasks (e.g., phonological decoding and morphological awareness); 2) studying both dyslexics and dysgraphics; and 3) presenting the children with tasks that involve both auditory and visual language stimuli (only auditory stimuli were given in their prior grant period).
Specific Aim 3 is to measure the effect of two contrasting language treatments on brain activation. We will test hypotheses about whether (a) different language tasks activate different brain regions, (b) effects of specific kinds of treatment age specific to brain regions subserving the language the language skill trained in a particular treatment.
Specific Aim 4 is to continue research on understanding both fMRS and fMRI outcome measures that can be used to evaluate brain activation. The fMRS pulse sequence parameters will be further optimized and additional MR-detectable chemicals will be investigated to improve our ability to detect biological markers of both cognitive and non-cognitive brain activation.
Specific Aim 5 is to link Projects III and IV through functional brain imaging of phonological memory, which was shown to be our best genetic candidate.
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