New imaging analysis techniques to probe causes of dyslexia

Sep 20 2004

Using sophisticated new software that integrates a variety of imaging methods, Wake Forest University Baptist Medical Center researchers will probe the mystery of what causes dyslexia with a four-year, $2.3 million grant from the National Institutes of Health.

“Dyslexia is a huge problem affecting 10 percent of children in the United States, yet very little is known about the cause,” said Joseph A. Maldjian, M.D., principal investigator on the project that will explore the neurobiological underpinnings of the disease.

Maldjian, associate professor of diagnostic radiology, plans to develop a statistical “toolbox” for analysis of multiple brain images, using functional MRI, diffusion imaging, three-dimensional spectroscopy and other new imaging techniques.

“Rather than imaging data being the end point for an analysis,” said Maldjian, “Let imaging data from one modality be used to drive analysis in another modality.”

For example, results from spectroscopy might be used to analyze data from functional MRI, or vice-versa. “This opens up an entirely new avenue of analytic possibilities for refined hypothesis-driven research that has been completely unavailable. The product of this grant will be distributed to the neuroscience community worldwide.”

The research group plans use these new tools first on dyslexia, though they can be applied to a variety of different disease processes.

Maldjian pointed out that the school has been a leader in dyslexia research dating back to the 1950s, and about 150 of those early subjects are still being followed by Frank B. Wood, Ph.D., head of the Section on Neuropsychology, and coinvestigator on the grant.

“Numerous studies have been performed and continue to be performed on these individuals, who enthusiastically support dyslexia research in the hope that future dyslexics might benefit,” Maldjian said.

Maldjian said 85 of these subjects have undergone regional cerebral blood flow brain imaging and 40 have participated in PET (positron emission tomography) studies of brain metabolism. The group also includes 11 extended families – about 225 individuals – who already have undergone behavioral testing and genetic analysis. And the group includes another 38 families starting with a father or mother with dyslexia and the spouse and children who also have undergone behavioral testing.

The subjects will now undergo various imaging tests using a variety of modalities and the research group will merge the results using the new statistical toolbox to answer the question: are there abnormal activation patterns in the brains of dyslexics?

“Dyslexia researchers agree that dyslexia has a neurobiological and genetic basis,” he said, “but the exact mechanisms of this disorder remain unknown, as researchers actively pursue some unifying theory for the constellation of deficits in dyslexia.”

This represents the third NIH funded grant awarded to the Advanced Neuroscience and Imaging Research Group (ANSIR) in the past 15 months. The research group, headed by Maldjian, includes Jonathan H. Burdette, M.D., associate professor of radiology, Paul J. Laurienti M.D., Ph.D., assistant professor of radiology, and Robert A. Kraft, Ph.D., assistant professor of biomedical engineering.