Improving Sleep, Sleep-related Outcomes, and Biomarkers in Veterans

This project will utilize a biobehavioral intervention to improve sleep and apply a novel approach to measuring biomarkers in Veterans with TBI. The investigators will use morning bright light therapy (MBLT) to improve sleep. MBLT acts through intrinsically photosensitive retinal ganglion cells and has pleiotropic effects on sleep, circadian rhythms, cognition, mood, and pain through activation of brain circuits.

MBLT is a simple, cost-effective, home-based sleep intervention. It has been studied in a variety of neuropsychiatric populations, such as seasonal affective disorder, non-seasonal depression, Alzheimer's, Huntington's, Parkinson's disease, and schizophrenia. MBLT is an attractive intervention for TBI as patients typically report multiple concomitant symptoms including alterations in mood and alertness (daytime fatigue). One recent placebo-controlled study using MBLT reported improved fatigue in individuals with TBI. Moreover, MBLT has high patient acceptability and is scalable, owing to its ability to be rapidly implemented in any setting including in the home or in a rehabilitation facility.

To address the substantial limitation of using peripheral biomarkers to understand central pathophysiology in TBI, the investigators have developed a method to use blood-based brain biomarkers (BBBM) to track central pathophysiology and symptomatology of TBI and response to treatment. This method entails isolation of neuronally derived exosomes in peripheral blood. Exosomes are membrane bound structures that, instead of being delivered to lysosomes for destruction, reside in multivesicular bodies, fuse with the plasma membrane, and are exocytosed into extracellular spaces. Within the membrane of exosomes are various proteins present in the cell of origin; thus, the cargo of exosomes reflects the microenvironment from the site of exosome production. Exosomes hold promise in TBI since they can readily cross the blood brain barrier (BBB) and be isolated from peripheral circulation. Studying exosomes allows us to isolate those proteins that are routinely disrupted in patients with TBI and sleep disturbances, and to track changes in accordance with treatment condition over time.

In this project, the investigators will conduct a randomized controlled, single blinded trial in which Veterans with and without TBI will receive MBLT or modified negative ion generator; (see below for modification specifications) for 4-weeks. BBBM will be assessed in conjunction with MBLT/sham and neurobehavioral symptomatology. The investigators hypothesize that: 1) MBLT will be associated with improved sleep, and downstream effectors of improved sleep (i.e., cognition, mood, and quality of life), compared to the sham condition; 2) MBLT will show a correlation between BBBM and improved sleep, and levels of BBBM will predict those that respond to MBLT. This will provide novel insights into how these biomarkers relate to neuronal and behavioral changes following TBI and may inform trajectory of recovery.

The study can be completed 100% remotely, in person, or a combination of the two.