Exploring the link among injury severity, white matter connectivity and psychosocial outcomes in pediatric TBI: a probabilistic tractography approach.

Aim: We examined associations among injury severity, white matter structural connectivity within functionally defined brain networks and psychosocial/adaptive outcomes in children with traumatic brain injury (TBI).

Method: Participants included 58 youths (39 male) with complicated-mild TBI (cmTBI; n = 12, age =  12.6 ± 2.0), moderate/severe TBI (msTBI; n =  16, age =  11.4 ± 2.9) and a comparison group with orthopedic injury (OI; n =  24, age =  11.7 ± 2.1), at least 1 year post-injury. Participants underwent diffusion tensor imaging and parents rated children's behavioral and adaptive function on the CBCL and ABAS-3, respectively. Probabilistic tractography quantified streamline density. Group differences were analyzed for structural connectivity and behavioral outcomes.

Results: Groups differed in structural connectivity within regions of the default mode and central executive networks (ps < .05, FDR corrected). The msTBI group displayed decreased connectivity relative to cmTBI and OI, whereas the cmTBI group displayed increased connectivity relative to msTBI and OI. Similar patterns emerged in several behavioral domains. Ordinary least squares path analyses showed that structural connectivity mediated the relationship between injury severity and multiple parent-reported outcomes for msTBI.

Interpretation: White matter structural connectivity may explain unique variance in long-term psychosocial and adaptive outcome in children with TBI, particularly in cases of moderate-to-severe injury.