1171 Short-Wavelength Light Therapy as A way of Improving Sleep, Cognition, and Functional Connectivity Following A mild Traumatic Brain Injury

Abstract

Supplement, 2017 TBI+PTSD, or Neither. Sleep was staged by two individuals blinded to group according to AASM criteria. EMG tone was classified as low (50% below median EMG tone), medium (50 to 80%) or high (EMG values 80% and above) and analyzed within each sleep stage. Group and individual differences were analyzed using chi-square and oneway ANOVA. Results: A surprisingly high number of Veterans self-reported a high rate of dream enactment and nightmares: 37% TBI, 63% PTSD, 76% TBI+PTSD, 27% controls for dream enactment (p<0.001; X 2 =57.9), and 26% TBI, 78% PTSD, 81% TBI+PTSD, 14% controls for nightmares (p<0.001; X 2 =247). The percentage of epochs classified with high EMG tone during REM sleep was 3.0% in TBI, 5.6% in PTSD, 7.8% in TBI+PTSD, and 4.2% in controls (p=0.049; F (3,284) Introduction:Mild traumatic brain injury (mTBI) has been associated with disruptions in sleep, limbic function, and increases in symptoms related to anxiety as a consequence of the injury. Evidence suggests that there is a relationship between improvements in neurobehavioral impairments and more regulated sleep architecture, but this relationship is not well understood. We hypothesized that among patients recovering from an mTBI, daily morning blue light therapy (BLT) would yield improvement in brain function, as evidenced by greater post-treatment functional connectivity between the medial prefrontal cortex (MPFC) and amygdala, and this would be associated with improvements in sleep and anxiety. Methods: Twenty-six adults (12 male; M age: 21.6 ± 3.9) with self-reported sleep disturbances subsequent to a documented mTBI within the preceding 18 months were recruited to receive either BLT or a placebo amber light therapy (ALT) for 30-minutes each morning over a six-week period. Participants underwent a six-minute resting state functional magnetic resonance imaging (fMRI) scan at 3T and completed neurocognitive testing at baseline and again at the conclusion of treatment. Regions of interest were placed in the amygdala (bilateral) and MPFC. Functional connectivity was analyzed utilizing the CONN toolbox with SPM12, p<.05, FDR corrected. Results: BLT was associated with significant increases in functional connectivity between the left amygdala and MPFC, whereas no change was observed for ALT. The increase in connectivity for BLT was associated with significant decreases in sleep onset latency, state anxiety, and perceived invincibility from baseline to post treatment. Conclusion: A six-week period of BLT produced improvements in sleep onset latency and anxiety that were associated with increased functional connectivity between the left amygdala and MPFC. BLT may provide an effective method for regulating the sleep wake cycle and improving cognition and emotion among individuals recovering from mTBI. Better sleep may serve to strengthen mPFC to amygdala connectivity, thereby improving emotional functioning. Introduction: Mild traumatic brain injury (mTBI) can lead to alterations in sleep, circadian function, and cogni...