Leads attached next to the eyes can capture eye movement, useful for revealing when a patient is in rapid eye movement, or REM, sleep.

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Alcohol reduces how much time we spend in rapid eye movement (REM) sleep - the stage of sleep where dreams generally occur.

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Wearable fitness devices are the current technology fad, with startups such as Jawbone and Fitbit, as well as larger companies like Nike and soon, reportedly, Apple, jumping in with devices to measure things like body movement and sleep.

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Narcolepsy is a brain disorder characterised by sleep attacks and abnormal eye movement which affects up to one in a thousand people.

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Eye movement is one of the few things that we do in both our dreams and with our bodies, hence the term Rapid Eye Movement, or REM sleep.

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