Shedding light on excessive sleepiness

Aug 8 2019

Dr Gemma Paech

It’s well known how debilitating insomnia can be, but what about the opposite effect – excessive sleepiness?

A HNE Health-led study will look at how light treatment can improve sleep, daytime functioning and sleepiness in those with hypersomnia (excessive sleepiness).

The study will trial the use of bright light exposure, via commercially available glasses, to better align patients’ internal body clocks with the outside environment. There is some evidence suggesting that hypersomniacs have a delayed circadian timing, with sleep occurring later at night.

HNE Health senior sleep scientist Dr Gemma Paech, who is leading the trial in collaboration with HMRI, said excessive sleepiness is highly prevalent in Australia.

”Around 19 per cent of the population experience excessive sleepiness. Despite obtaining adequate and good-quality uninterrupted sleep, individuals with hypersomnia wake feeling unrefreshed and are in an almost constant state of sleepiness,” Dr Paech said. “It impacts their life in many ways as they can fall asleep at any time - at work or potentially when driving.”

The study will also consider changes in waking functions such as reaction time and mood in order to improve patients' overall quality of life.

The condition differs from other sleep disorders such as narcolepsy and sleep apnoea as patients regularly sleep more than 70 hours per week. Currently there are no pharmacological treatments available to specifically treat hypersomnia. Non-pharmacological therapies such as light exposure may offer alternative, non-invasive treatment options.

“Light exposure has been shown to improve subjective sleepiness, alertness and waking functions. Light is also the primary synchroniser between external and internal circadian rhythms. In other words, light helps to keep internal circadian rhythms aligned with external factors, such as the 24-hour day,” Dr Paech said.

Depending on the timing of exposure, light can shift circadian rhythms. Exposure to light in the early morning can shift sleep earlier and exposure to light in the evening can shift sleep later at night.

“In patients with hypersomnia, morning light exposure can work to advance sleep, keeping the internal and external rhythms aligned which could improve concentration, memory, attention, alertness and decrease sleepiness,” Dr Paech said.

The trial is aiming to recruit 20 patients with hypersomnia (including idiopathic hypersomnia). Ten will be randomised into a light treatment and 10 into behavioural treatment condition. Participants assigned to the light treatment will wear re-timer light therapy glasses each morning for 30-60 minutes after waking, while the other group will be given a series of actions to complete at home.

Anyone who is interested in being part of the study can email gemma.paech@health.nsw.gov.au

HMRI is a partnership between Hunter New England Health, the University of Newcastle and the community.