Short-Wavelength Countermeasures for Circadian Desynchrony

http://www.dtic.mil/cgi-bin/GetTRDoc?AD=ADA488544&Location=U2&doc=GetTRDoc.pdf



Exposure to light at critical phases of the circadian cycle entrains circadian rhythms. Exposure of humans to bright light for an hour or more at the right phase of the circadian cycle produces significant phase shifts of circadian rhythms speeding recovery from jet-lag, and optimizing cognitive functionality and restorative sleep. Our work on mice produced the unexpected result that exposure to intermittent millisecond flashes of light distributed over an hour for a total of only 120 msec. of light can produce maximum phase shifts. Our specific aims were: 1) build a prototype, programmable photodiode based device to deliver light flashes of 1 to 3 msec duration to a person's eyes, 2) conceptualize a commercializable wearable device containing an algorithm that will provide an automatic flash delivery schedule, 3) test whether or not the human circadian system is susceptible to phase resetting by appropriately delivered millisecond flashes of ligh t, and 4) plan experiments to define optimal stimulation protocols. We built the prototype, we have also built prototypes of wearable commercializable devices with a flash delivery algorithm. Tests of flash effects on human circadian rhythms are underway. And, our plans for future experiments have been incorporated into our Phase II proposal