Physicians may make a preliminary diagnosis of Narcolepsy based on a persons experience of both excessive daytime sleepiness (EDS) and sudden loss of muscle tone (Cataplexy) - the hallmark symptoms of Narcolepsy. After an initial diagnosis, physicians will usually refer the person to a sleep specialist for additional studies and evaluation. Formal diagnosis may require staying overnight at a sleep centre. There, electroencephalogram (EEG) electrodes are placed on the scalp before falling asleep in a comfortable, quiet room. Sleep technicians in another room monitor brain activity while the patient is sleeping.

The next day, the patient will be asked to try and nap several times. Specialists will observe how quickly sleep occurs and whether REM sleep occurs. People with Narcolepsy generally fall asleep in 8 minutes or less; they also enter REM sleep at least 50% of the time. On average, Narcoleptics enter REM sleep phase 90 minutes quicker than non-sufferers.

THE FOUR CLASSIC SYMPTOMS OF NARCOLEPSY - IN A NUTSHELL

1. Excessive Daytime Sleepiness (EDS) - primary characteristic is an overwhelmng drowsiness and uncontrollable need to sleep during the day.

2. Cataplexy - Cataplexy, the sudden loss of muscle tone, is the second most common symptom of Narcolepsy. It can cause physical changes which can range from slurred speech and weakness of muscles through to total collapse. Attacks can last anything from a few seconds, to much longer periods. Cataplexy is often triggered by strong emotional responses.

3. Sleep Paralysis - Less commonly, people with Narcolepsy experience a temporary inability to move or speak while falling asleep or waking. Sleep paralysis is characteristic of the immobility that often accompanies REM sleep, which experts believe serves to prevent the body from acting out dream activity.

4. Hyponagogic Hallucinations - These hallucinations may take place when people with Narcolepsy fall quickly into REM sleep. Because they may be semi-awake when they begin dreaming, they experience dreams as reality.

According to the National Institutes of Health in the USA, the majority of people with Narcolepsy experience both EDS and Cataplexy, while the other two symptoms occur in 25 to 50 percent of affected people.

Other Narcolepsy symptoms include restless night-time sleep and occasional automatic behaviour. During episodes of automatic behaviour, the affected person performs routine tasks without awareness or memory of doing them.

TIPS AND TRICKS IN MANAGING THE SYMPTOMS

If you have Narcolepsy, you may benefit from trying the following measures if you are able, and your daily circumstances permit -

Sleep and wake at the same time every day, including weekends
Schedule several naps of 10-15 minutes each day
Avoid caffeine and nicotine
Inform your employer or teachers about your condition and work to find ways to accomodate your needs (ie taking naps during the day)
Break up monotonous tasks
Tape record meetings or class periods
Stand during meetings or lectures
Take brisk walks at various points during the day

NB - Whilst these measures on managing the symptoms are undoubtedly beneficial to some sufferers, it must be said that many Narcoleptics are simply not in a position where they can schedule time to do these things.