Perinatal Stroke: Understanding Brain Reorganization

The incidence of perinatal stroke is relatively common, as high as 1 in 2,300 births, but little is known about the resulting changes in the brain that eventually manifest as cerebral palsy (CP). Motor signs that indicate the infant is beginning to develop CP often do not become evident for several months after the diagnosis of perinatal stroke which delays therapy. The main purpose of this study is to examine early brain reorganization in infants 3-12 months of age corrected for prematurity with perinatal stroke using magnetic resonance imaging (MRI) and non-invasive transcranial magnetic stimulation (TMS). In addition, the association between the brain reorganization and motor outcomes of these infant participants will be identified. In this study, the MRI scans will include diffusion tensor imaging (DTI) - an established method used to investigate the integrity of pathways in the brain that control limb movement. Infants will be scanned during nature sleeping after feeding. The real scanning time will be less than 38 minutes. TMS is a painless, non-surgical brain stimulation device which uses principles of electromagnetic induction to excite cortical tissue from outside the skull. Using TMS as a device to modulate and examine cortical excitability in children with hemiparetic CP and in adults has been conducted previously. In this infant study, we will assess cortical excitability from the motor cortex of both the ipsilesional and contralesional hemispheres under the guidance of a frameless stereotactic neuronavigation system. Additionally, the investigators will assess infants' movement quality using an age-appropriate standardized movement assessment. This will allow the investigators to examine the relationship between measures of motor pathway integrity and early signs of potential motor impairment. We will longitudinally follow enrolled infants, and complete repeat assessments at 12- and 24-months corrected age to assess how infants develop over time after