Introduction This MRC Confidence in Concept funded study (Clinical Trials reference: NCT03867513) combined magnetoencephalography (MEG) with ultrahigh field 7T MRI, to look for functional and struc- tural abnormalities in mild traumatic brain injury (mTBI).

Objectives Can those with mTBI be differentiated from non-head injured orthopaedic trauma controls by measuring brain wave activity.

Methods We scanned 40 participants within two weeks of an emergency department visit and they underwent resting state and task specific MEG followed by 7T MRI including structural, susceptibility, and diffusion sequences. Questionnaire assessment was completed at baseline, three, and six months.

Results Whilst most individuals with mTBI recover a significant proportion have persistent difficulties. Using a Hidden Markov Model in the mTBI cohort, we were able to demonstrate reduced beta band connec- tivity results from a loss in the temporal coincidence of bursts of activity in spatially distinct regions. This replicates our findings in a distinct sub-acute mTBI cohort. Susceptibility weight imaging revealed only two mTBI participants with microhaemorrhages, their clinical care, markers of injury severity, and recovery did not differentiate them from others in the mTBI cohort.

Conclusions Our results suggests that mTBI may impair the dynamic coordination of neural network activity and this requires further exploration.