Diverging white matter trajectories in children after traumatic brain injury: The RAPBI study
Emily L Dennis1, Faisal Rashid2, Monica U Ellis2
1From the Imaging Genetics Center (E.L.D., F.R., J.E.V.-R., Y.J., P.M.T.), Mary and Mark Stevens Institute for Neuroimaging and Informatics, Keck School of Medicine, University of Southern California, Marina del Rey; Department of Psychiatry and Biobehavioral Sciences, Semel Institute for Neuroscience and Human Behavior (M.U.E., T.B., A.O., R.F.A.), Department of Psychology (R.F.A.), and Brain Research Institute (R.F.A.), UCLA, Los Angeles; Fuller Theological Seminary School of Psychology (M.U.E.), Pasadena; CIBORG Laboratory (R.M.V.), Department of Radiology, Children's Hospital Los Angeles, CA; Department of Psychology (A.O.), Norwegian University of Science and Technology; Department of Physical Medicine and Rehabilitation (A.O.), St. Olavs Hospital, Trondheim University Hospital, Norway; Harbor-UCLA Medical Center and Los Angeles BioMedical Research Institute (R.M.), Department of Pediatrics, Torrance; Miller Children's Hospital (C.B.), Long Beach; Department of Pediatrics (J.J.), LAC+USC Medical Center; Department of Neurosurgery and Division of Pediatric Neurology, UCLA Brain Injury Research Center (C.C.G.), Mattel Children's Hospital; and Departments of Neurology, Pediatrics, Psychiatry, Radiology, Engineering, and Ophthalmology (P.M.T.), USC, Los Angeles, CA. emily.dennis@ini.usc.edu.
Insights
Children with moderate/severe traumatic brain injury (msTBI) and slow interhemispheric transfer time (IHTT) show declining white matter organization. This suggests a potential biomarker for progressive neurodegeneration in pediatric msTBI.
Area of Science:
- Pediatric neurology
- Neuroimaging
- Traumatic Brain Injury Research
Background:
- Pediatric moderate/severe traumatic brain injury (msTBI) can impact white matter (WM) organization.
- Longitudinal changes in WM microstructure following pediatric msTBI are not well understood.
Purpose of the Study:
- To investigate the longitudinal changes in white matter (WM) organization over 12 months in children with moderate/severe traumatic brain injury (msTBI).
- To identify potential biomarkers for progressive neurodegeneration in pediatric msTBI.
Main Methods:
- Studied 21 children with msTBI and 20 healthy controls, with assessments 2-5 and 13-19 months post-injury.
- Assessed corpus callosum function using interhemispheric transfer time (IHTT) via event-related potentials.
- Correlated IHTT with diffusion-weighted MRI measures of white matter (WM) microstructure.
Main Results:
- Children with msTBI were categorized into those with normal (TBI-normal-IHTT) and slow (TBI-slow-IHTT) interhemispheric transfer times (IHTT).
- The TBI-normal-IHTT group showed no significant differences in WM organization compared to controls.
- The TBI-slow-IHTT group exhibited significantly lower WM organization and a progressive decline in WM organization over the 12-month period.
Conclusions:
- Preliminary evidence suggests impaired callosal organization in the early months post-msTBI may identify a subset of children at risk.
- This subset experiences continuing and progressive widespread white matter degeneration in the first year post-injury.
- Slow IHTT may serve as a potential biomarker for identifying progressive neurodegeneration in pediatric msTBI.
Objective:
To examine longitudinal trajectories of white matter organization in pediatric moderate/severe traumatic brain injury (msTBI) over a 12-month period.
Methods:
We studied 21 children (16 M/5 F) with msTBI, assessed 2-5 months postinjury and again 13-19 months postinjury, as well as 20 well-matched healthy control children. We assessed corpus callosum function through interhemispheric transfer time (IHTT), measured using event-related potentials, and related this to diffusion-weighted MRI measures of white matter (WM) microstructure. At the first time point, half of the patients with TBI had significantly slower IHTT (TBI-slow-IHTT, n = 11) and half were in the normal range (TBI-normal-IHTT, n = 10).
Results:
The TBI-normal-IHTT group did not differ significantly from healthy controls, either in WM organization in the chronic phase or in the longitudinal trajectory of WM organization between the 2 evaluations. In contrast, the WM organization of the TBI-slow-IHTT group was significantly lower than in healthy controls across a large portion of the WM. Longitudinal analyses showed that the TBI-slow-IHTT group experienced a progressive decline between the 2 evaluations in WM organization throughout the brain.
Conclusions:
We present preliminary evidence suggesting a potential biomarker that identifies a subset of patients with impaired callosal organization in the first months postinjury who subsequently experience widespread continuing and progressive degeneration in the first year postinjury.
