Honours Opportunity - Portable Light Device

BMedSci Honours Project 2019

Project Subject Area(s):- Evaluation of a portable light device for phase advancing the circadian rhythms of those suffering sleep onset insomnia


Brief Outline of Project: Circadian rhythms fundamentally determine the timing of sleep and wakefulness across the 24-hour day. An individual with a ‘normally’ timed circadian rhythm will typically fall asleep at approximately 11pm and wake around 7am. However chronic sleep difficulties can occur when the circadian rhythm is mis-timed, leading to a sleep-wake rhythm that does not coincide with an individual’s preferred sleep-wake schedule. A late timed circadian rhythm can lead to difficulty falling asleep. Sleep onset insomnia is associated with delays of the circadian rhythm in the order of 2-3 hours. Later sleep onset times increase the tendency to sleep later into the morning in a bid to obtain sufficient sleep. However, when required to rise for work or social obligations (e.g. at 7am), an individual with a delayed circadian rhythm will experience extreme difficulty as they are attempting to rise at the time of maximum circadian sleepiness. The negative experience of this physiologically based difficulty, coupled with insufficient sleep, can amplify the negative consequences of difficulty falling asleep and reinforce the cycle of chronic insomnia.

Appropriately timed exposure to bright light can re-time (or phase shift) the circadian rhythm and consequently alleviate the associated sleep difficulties and daytime sequelae. Although the efficacy of morning bright light has been well established to advance (move earlier) the circadian phase, few studies have investigated its efficacy for the treatment of sleep onset insomnia associated with a delayed circadian phase. Bright light has traditionally been administered using a ‘light box’, which requires individuals to maintain a fixed position in front of the box. This is impractical and impacts significantly on treatment compliance. Since the development of light boxes, it has become well established that coloured blue/green light, as opposed to white light, produces a superior therapeutic response.

Based on a great deal of our previous research from our group showing that optical devices using small Light Emitting Diodes, particularly using blue/green light, can change the timing of our endogenous body clock, commercial devices have been developed. These devices are now available to the public for a variety of beneficial effects including the treatment of circadian rhythm disorders contributing to insomnia, jet-lag, winter depression and shift work disorder.

These commercial devices based on this earlier research need to be validated for their effectiveness. We have previously shown that they are effective at delaying the body clock timing when used in the evenings, and advancing the body clock timing when used in the mornings. This research was conducted using individuals who experience typically good sleep. We need now to show their effectiveness in shifting the body clock when used in a clinical population with sleep onset insomnia. No other light therapy devices on the market at present have evidential support for their effectiveness.


For further information please contact Dr Nicole Lovato

E: nicole.lovato@flinders.edu.au

T: 08 7221 8307