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Incidence & symptoms

       Usually begins in adolescence or early adulthood, continues through the person’s life

       About 1 in 2000 people suffer from narcolepsy but this is an estimate as some people only have mild symptoms or just don’t go to their doctors


      sudden and uncontrollable attacks of sleep, at any time

      Several times a day

      Last 10-20 mins

      Sudden loss of muscular control – collapse, several times a day

      Auditory or visual hallucinations as falling asleep or waking up

      Sleep paralysis

Explanations of narcolepsy 1 – AO1

       Polysomnography (i.e brain activity, body & eye movements, heart rate, BP, O2 levles)  show REM sleep occurs at the onset of sleep in narcoleptics – they don’t go through stages.

       This explains some of the symptoms e.g. the loss of muscle tone leading to collapse, hallucinations (seen as REM-type sleep and dreams intruding into the day).

       Suggest narcolepsy is due to abnormality in control of REM sleep mechanism but WHY .....!

       Dement 1970’s investigated some dogs who develop narcolepsy, if they are bred together they are very vulnerable to cataplexy (sudden collapse when excited).

       In the 1990’s it was found they had a problem with a gene on chromosome 12 which controls a neurotransmitter  called hypocretin, thought to be vital in maintaining wakefulness.

       Lin et al (1999) found that narcoleptic dogs had low levels of hypocretin.

       Thannickal et al 2000: narcoleptic humans had less hypocretin producing cells in the hypothalamus.

       Research also suggested a link with a gene on chromosome 6 (the HLA complex gene) which regulates the immune system.

       It seems that this leads to the immune system attacking and destroying the hypocretin neurones in the


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