Low-Level Light Therapy Effect on Resting-State Connectivity in Patients Following Moderate Traumatic Brain Injury

Abstract Recent studies demonstrate that low-level light therapy (LLLT) modulates recovery in patients with traumatic brain injury (TBI). However, the impact of LLLT on brain activity following TBI has not been well described. Here we use a randomized, double-blind, placebo-controlled design to investigate the effect of LLLT on resting-state connectivity at acute (within 1-week), subacute (2–3 weeks), and late-subacute (3-month) time-points following moderate TBI. A characteristic connectivity profile was observed during TBI recovery in both sham- (n = 21) and LLLT-treated patients (n = 17) compared to healthy controls, with increased resting-state connectivity between frontal and parietal cortices. Temporal comparisons between LLLT- and sham-treated patients showed that the acute-to-subacute changes in resting-state connectivity were significantly greater in LLLT-treated patients. These results demonstrate that LLLT increased resting-state connectivity in the presence of a regional hyperconnectivity response to moderate TBI, suggesting that LLLT can modulate activity in the injured brain and encouraging its further exploration as a therapy for TBI.