Changes in working memory-related cortical responses following pediatric mild traumatic brain injury: A longitudinal fMRI study

Persistent post-concussion symptoms (PPCS) lasting longer than 4 weeks affect 25% of children with mild traumatic brain injury (mTBI) or concussion. Working memory (WM) problems are a common complaint in PPCS. Despite normal function on traditional neuropsychological tests, these exhibit aberrant cortical responses within the dorsolateral prefrontal cortex (dlPFC) and default mode network (DMN) regions – both which implicated WM. Using prospective, longitudinal cohort study design, we investigated changes fMRI dlPFC DMN during an nback WM task at two timepoints: one months post-injury. Across timepoints, primary outcome was change activations (increase BOLD) deactivations (decrease DMN. Twenty-nine (mean age 15.49 ± 2.15; 48.3% male) scans timepoints were included, following data quality control. Student’s t-tests used to examine across time difficulty. ANCOVA F-tests examined after removal baseline time, difficulty recovery. Volumes interest (5 mm sphere) placed peak voxel compare between recovered unrecovered participants over (one-way ANOVA). Between post-injury, found significant increases increasing difficulty, alongside improved performance. Cortical bilateral displayed increased intensity participants, together attention behavioural symptoms. Overall, our findings suggest evidence neural compensation ongoing cognitive recovery from pediatric TBI post These results highlight wider persisting implications mTBI children, whose maturing brains particularly vulnerable TBI.