Understanding excessive daytime sleepiness in children

Children who experience excessive daytime sleepiness are referred to the Melbourne Children's Sleep Centre for assessment of idiopathic hypersomnolence or narcolepsy. Narcolepsy is a neurological disorder that affects your ability to wake and sleep. People with narcolepsy have excessive, uncontrollable daytime sleepiness. They may also suddenly fall asleep at any time, during any type of activity. Usually when you fall asleep you go through stages of non rapid eye movement (NREM) sleep, however people with narcolepsy go into REM sleep almost immediately in the sleep cycle and sometimes while they’re awake. Idiopathic hypersomnia is similar in presentation to narcolepsy, but patients with this condition have no sleep-onset REM period, and naps are unrefreshing. Children with excessive daytime sleepiness are referred for an overnight sleep study at the Melbourne Children's Sleep centre, the following day children undergo a Multiple Sleep Latency Test where they are given the opportunity to try to nap every two hours throughout the day. There are two things being looked at: how long it takes the child to go to sleep and what type of sleep do they have when they go to sleep. There have been case reports and small studies demonstrating autonomic dysfunction in adults with idiopathic hypersomnolence, there are few studies in children. Narcolepsy is associated with low hypocretin 1 levels. Hypocretins are involved in regulation of heart rate and blood pressure. This study will use heart rate variability as a non invasive measure of autonomic control to examine differences in autonomic control between children diagnosed with narcolepsy, idiopathic hypersomnolence and control children. Students will have the opportunity to be involved in sleep studies and will analyse heart rate and sleep data collected from clinically referred children with and without excessive sleepiness.