Current Research and Scholarly Interests
I am a developmental-behavioral pediatrician and a research developmental-cognitive- neuroscientist. I became interested in the development of language as a graduate student in developmental psychology. Language development in young children becomes central to their abilities to learn, acquire information, communicate, and participate fully in the human social experience. As a pediatrician, I became aware that many clinical conditions put language learning at risk. Over the years I have studied the outcomes of several important clinical conditions.
Prior to arrival at Stanford, I was part of an interdisciplinary team that investigated the long-term developmental consequences of otitis media with effusion. This research has documented that early placement of tympanostomy tubes restores normal hearing but does not confer any developmental advantages over watchful waiting in children with chronic middle ear effusions. Because the design of the study was a randomized clinical trial, the strong implication is that middle ear effusion does not cause developmental compromise in speech, language, cognition, or reading. The results have major clinical significance and have been cited in the revisions of practice guidelines for management of otitis media with effusion.
I was also interested in the impact of early focal injuries to the left hemisphere of the brain because in adults this hemisphere processes language. We described that children with such injuries learn to understand and speak competently during the preschool years, though some show mild to moderate developmental delays. Differences between children with left and right hemisphere damage are minimal even though the hemispheres seem to function very differently in adults. Children with focal injuries continue to perform only mildly below the level of their age-matched peers into school age, though both groups show improvements in performance at least through at 12 years. Functional magnetic resonance imaging documented increased right hemisphere activation during language processing after focal left hemisphere injury. These studies provide an insight into the mechanisms of plasticity in the neural systems of language development.
Since arriving at Stanford, my research has focused on language and cognition after preterm birth. Children born preterm show differences in characteristics of the white matter of the brain. Our initial studies in older children and adolescences documented that structural characteristics of long-range white matter tracks were associated developmental outcomes after preterm birth. We replicated many of the initial findings in a cohort of children who are entering elementary school and just beginning to learn to read. We learned that properties of white matter predict later reading in children born at term, but not in children born preterm. We are pursuing multiple approaches to characterizing white matter to understand the basic neurobiology of white matter in children born preterm. We are now focusing on children born preterm from birth to 18 months of age. We hope to characterize interactions between the development of white matter circuits and social, psychological, and environmental factors on early language processing skills.
I am also extremely interested in improving the delivery of health care to all children with developmental and behavioral disorders. I serve as the site PI for DBPNet, a research consortium of 14 academic health centers that collaborate to improve health care and health outcomes for children with autism spectrum disorders, attention deficit disorder, and other neurodevelopmental conditions.