A systematic review of brain structural and functional alterations in pediatric mild traumatic brain injury.

INTRODUCTION

Pediatric mild traumatic brain injury (pmTBI) constitutes 70-90% of childhood traumatic brain injury cases. While magnetic resonance imaging (MRI) reveals subtle brain alterations, fragmented evidence across modalities limits understanding of long-term neurobiological consequences.

METHODS

This systematic review synthesized 42 studies from MEDLINE/PubMed, Web of Science, Cochrane Library, and Scopus (inception to December 2025) employing structural MRI and functional MRI (fMRI). Methodological quality was assessed using a modified GRADE framework.

RESULTS

White matter investigations (n = 18) suggested widespread microstructural alterations in limbic and commissural pathways-alongside reduced global network efficiency and disrupted hub connectivity in executive and salience networks. Gray matter studies (n = 9) identified regional cortical thinning in prefrontal and parietal regions, hippocampal atrophy persisting up to 1 year. Resting-state fMRI studies (n = 5) revealed diminished default mode network (DMN) integrity and elevated striatal spontaneous activity. Task-based fMRI studies (n = 10) demonstrated compensatory hyperactivation during working memory and inhibitory tasks-manifesting as enhanced preparatory activation but resource depletion during execution-alongside lower DMN deactivation and persistent cerebrovascular reactivity abnormalities extending to chronic phases.

DISCUSSION: In sum, multimodal MRI provides evidence suggesting systematic structural and functional alterations in pmTBI encompassing white matter disruption, gray matter vulnerability, and network reorganization.