Chronic Outcomes in Interhemispheric Transfer Time Among Children with Moderate to Severe Traumatic Brain Injury

Background: Each year, nearly ½ million youth under 15 years old sustains a traumatic brain injury (TBI). Although racial disparities have not been found in pediatric TBI (Howard, Joseph, & Natale, 2005), the consequences of TBI still remain a serious public health concern. Moderate and severe TBI (msTBI) frequently result in diffuse axonal injury and other white matter damage. The corpus callosum (CC) is particularly vulnerable to injury, though the impact of this damage may not be apparent until several months-to-years following injury. Damage to the CC has been associated with impaired neurocognitive functioning in youth with TBI. Method: The investigator for this dissertation study utilized event-related potentials, an electrophysiological measure of neural processing, to measure interhemispheric transfer time (IHTT) as an indicator of CC integrity in 31 youth with msTBI at the chronic phase of recovery (i.e., 13-18 months post injury), compared with 20 healthy control youth. Neurocognitive performance was also examined among these groups. Results: At the chronic phase of recovery, TBI group youth overall demonstrated slower IHTTs and worse neurocognitive functioning than youth in the control group. Only a subset of msTBI group children had IHTTs that were outside the range of the healthy controls; however, this impairment in interhemispheric communication was not significantly associated with neurocognitive performance. A pattern of differential impairments emerged between TBI group participants. Chronic-phase outcomes in IHTT were correlated with the presence of neurosurgery at the acute phase of injury. Conclusion: Overall, this study demonstrated that msTBI results in longstanding differences in interhemispheric and neurocognitive functioning, but injured children are differentially impacted. Functional reorganization resulting from neuroplasticity may help explain these results among children with slow IHTT but intact neurocognitive functioning. However, interpretations regarding the course of recovery could not be made due to the cross-sectional methodology used in this study. Investigators conducting future studies might explore additional outcomes associated with interhemispheric and neurocognitive functioning following msTBI at the chronic phase of recovery, including corresponding structural and metabolic changes using advanced imaging techniques