Investigation of neurobiological responses to theta burst stimulation during recovery from mild traumatic brain injury (mTBI).

Objective: The ability of the brain to recover following neurological insult is of interest for mild traumatic brain injury (mTBI) populations. Investigating whether non-invasive brain stimulation (NIBS) can modulate neurophysiology and cognition may lead to the development of therapeutic interventions post injury. The purpose of this study was to investigate neurobiological effects of one session of intermittent theta burst stimulation (iTBS) to the dorsolateral prefrontal cortex (DLPFC) in participants recovering from mTBI.

Method: Changes to neurophysiology were assessed with electroencephalography (EEG) and transcranial magnetic stimulation combined with EEG (TMS-EEG). Digit span working memory accuracy assessed cognitive performance. 30 patients were assessed within one-month of sustaining a mTBI and 26 demographically matched controls were assessed. Participants were also assessed at 3-months (mTBI: N = 21, control: N = 26) and 6-months (mTBI: N = 15, control: N = 24).

Results: Analyses demonstrated iTBS did not reliably modulate neurophysiological activity, and no differences in cognitive performance were produced by iTBS at any assessment time-point.

Conclusions: Factors responsible for our null results are unclear. Possible limitations to our experimental design are discussed.

Significance: Our findings suggest additional research is required to establish the effects of iTBS on plasticity following mTBI, prior to therapeutic application.

Data And Code Availability Statement: We do not have ethical approval to make this data publicly available, as our approval predated our inclusion of such approvals (which we now do routinely).