Narcolepsy is a sleep disorder which is characterised by extreme excessive daytime sleepiness, sleep paralysis, audio and visual sleep hallucinations and sometimes cataplexy. People with narcolepsy have an abnormally fast transition from wake-to-sleep and sleep-to-REM sleep.
The sleep-wake function in people with narcolepsy does not function correctly, leaving them feeling abnormally sleepy during the day, despite regularly achieving adequate sleep of a night time. There are some cases where individuals fall asleep involuntarily at inappropriate times. Others suffer the effects of cataplexy, where there is a dramatic decrease in muscle tone during times of high emotion (laughter, crying) and their body can become limp.
If a person is chronically sleep deprived (either by a lack of sleep or effects from a pre-existing sleep disorder such as OSA) they may present with some symptoms of narcolepsy. Therefore narcolepsy can only be diagnosed by first ruling out any other sleep disorder and ensuring that adequate sleep is being achieved on a regular basis.
An attended sleep study is required to objectively demonstrate no pre-existing sleep disorder. This overnight sleep study is then followed by a daytime sleep study called a Multiple Sleep Latency Test (MSLT). The MSLT is designed to objectively measure sleepiness through recording the transitions from wake-to-sleep and sleep-to-REM sleep, throughout a number of tests during the day.
There is no known cure for narcolepsy, however some medications and behavioural changes can help improve the symptoms increase quality of life.