Harvard Catalyst Profiles

My research activities over the past several decades have focused on the neuropsychology of learning disorders in school age children. The work can be organized loosely in to two main areas: developmentally based and medically related learning disorders. The studies have integrated multiple aspects of learning disorders, including neural correlates, outcomes associated with medical therapies, diagnostic considerations, and social contextual influences.

Developmental. My research on developmentally based learning disorders has grown out of my clinical experience in the Learning Disabilities Program at Children’s Hospital Boston, informed by my training in developmental psychology and neuropsychology. Whereas most psychologists and educators view academic achievement deficits as the core diagnostic feature of learning disabilities, my theoretical approach has emphasized learning disorders broadly as developmentally constructed phenomena arising from the dynamic interaction of biological and environmental forces in development. This constructivist approach places the focus on the child in developmental context rather than on a modular skill. In more than 20 publications, my colleagues and I established that children with learning problems are distinguished by variation in the basic building blocks of information processing, which themselves are linked to both physiological markers (EEG, fMRI) and to academic and social functioning. More recently, we have applied the same theoretical framework to the problem of the achievement gap, demonstrating that differences in academic achievement between historically disadvantaged minority and white children are related to variation in neurodevelopmental functions other than the academic skills of interest.

Medically Related. My work on the CNS impact of medical conditions and their therapy has been focused primarily on acute lymphoblastic leukemia (ALL). As the ALL Consortium at Dana-Farber Cancer Institute (DFCI) has expanded, our research program has grown to include 10 collaborating institutions in North America. The early studies documented significant cognitive morbidity among children treated successfully for ALL, and our group was the first to report a dramatic sex difference, with females being far more vulnerable to toxicity. Our findings and those of other investigators motivated pediatric oncologists to seek less toxic therapies. Dose reduction or elimination of cranial irradiation therapy (CRT) has resulted in a significant improvement in cognitive outcomes, particularly for females. We have more recently reported excellent efficacy of therapy without significant cognitive morbidity among a cohort of children treated with 1800 cGy CRT as well as the results of several randomized trials intended to reduce morbidity associated with therapy. Current work is focused on the impact of steroid therapies on CNS development, specifically prospective evaluation of children randomized to either prednisone or dexamethasone for their steroid therapy.

In addition to these primary areas of concentration, related areas of work in recent years have included studies of adult outcomes in children who experienced significant malnutrition in the first year of life, a large multi-site study of the structural and functional development of the human brain from birth to young adulthood, as well as collaborative involvement in studies of children with epilepsy, brain tumors and prenatal cocaine exposure, as well as functional magnetic resonance imaging in children.