CIRCADIAN MISALIGNMENT AS AN ENDOPHENOTYPE FOR DEPRESSION

Abstract

occur chronically, across the range of injury severity, and negatively impact on acute recovery, long term rehabilitation, mood and quality of life. Effective treatment is not well established. Recent research investigating short wavelength (blue) light exposure has demonstrated potency for acute subjective and physiological alerting effects, circadian phase shifting and enhancement of mood. The current study aimed to investigate the effects of 4 weeks of short-wavelength light therapy (LT) on fatigue and excessive daytime sleepiness (EDS) in individuals with TBI. Materials and Methods: Using a randomised, placebo-controlled design, we investigated a 4-week, 45min/day ‘at-home’ treatment with short wavelength (blue) light therapy (goLITE®, Philips Lighting) (465nm, 85 μW/cm2) compared with yellow light therapy (574nm, 19 μW/cm2) designed specifically to be deficient in short wavelength blue light or treatment as usual in 25 individuals (8, 9, 8) with TBI who self reported fatigue and/or EDS. Subjective assessments of fatigue and EDSwere conducted at baseline (week 0), mid-way through and at the end of LT (weeks 4 & 6), and again 4 weeks following cessation of LT (week 10). Results: We observed a trend for the mean decrease in fatigue (from baseline) across the 4-week treatment phase to be highest in the blue group (-1.14±1.25), compared with yellow (-0.17±0.64) or treatment as usual (-0.24±0.74), (p=0.07). The mean decrease in EDS was also highest in the blue group (-4.00±5.25) compared with yellow (-2.61±2.50) and treatment as usual (-0.56±2.57), although group differences were not significant (p=0.19). Conclusion: Preliminary findings suggest that short wavelength light may be effective in alleviating fatigue and possibly EDS following TBI. The trial is ongoing. Acknowledgements: Supported by grants from: The Jack Brockhoff Foundation, Centre for Integrated Research and Understanding Sleep (CIRUS, Woolcock Institute of Medical Research), RACV Sir Edmund Herring Memorial Scholarship, and Victorian Neurotrauma Initiative. goLITE®