Narcolepsy is a neurological disorder caused by the brain’s inability to regulate sleep-wake cycles normally. This sleep disorder causes overwhelming and severe daytime sleepiness and it can happen at inappropriate times and places. The daytime sleep attacks may occur with or without warning, and can occur repeatedly in a single day. Persons with narcolepsy often have fragmented nighttime sleep with frequent brief awakenings.
Despite the perception that people with narcolepsy are perpetually sleepy, they do not typically sleep more than the average person. That is, narcolepsy patients sleep a normal amount but cannot control the timing of sleep.
The main features of narcolepsy are excessive daytime sleepiness and cataplexy. The disease is also often associated with sudden sleep attacks, insomnia, dream-like hallucinations, and a condition called sleep paralysis.
- Excessive daytime sleepiness – this is usually the first symptom to appear in people who have narcolepsy. Unless they’re being treated for the disorder, the need to sleep can be overwhelming for narcolepsy patients: someone who has narcolepsy is prone to falling asleep while engaged in conversation, driving, eating dinner, or at other inappropriate times. The sleepiness occurs in spite of a full night’s sleep and may persist throughout the day.
- Cataplexy – cataplexy is a sudden loss of muscle tone, usually triggered by emotional stimuli such as laughter, surprise, or anger. It may involve all muscles and result in collapse. It may only affect certain muscle groups and result in slurred speech, buckling of the knees, or weakness in the arms. Consciousness is maintained throughout the episode but the patient is usually unable to speak.
- Hypnogogic hallucinations – during transition from wakefulness to sleep, the patient has bizarre, often frightening dream-like experiences that incorporate his or her real environment.
- Sleep paralysis – a temporary inability to move during sleep-wake transitions. Sleep paralysis may last for a few seconds to several minutes and may accompany hypnagogic hallucinations.
- Disturbed nocturnal sleep – waking up repeatedly throughout the night. Leg jerks, nightmares, and restlessness.
Narcolepsy affects both sexes equally and develops with age; symptoms usually first develop in adolescence or young adulthood and may remain unrecognized as they gradually develop. The instance of a familial connection with narcolepsy is quite small but a combination of genetic and environmental factors may be at the root of this sleep disorder.
Its prevalence in the developed world is approximately the same as that of multiple sclerosis or Parkinson’s disease. However, with increased public education about narcolepsy and physician training in the diagnosis and treatment of sleep disorders, these figures are expected to rise.
Researchers believe that narcolepsy may be caused by a deficiency in hypocretin production in the brain. The results of one recent study, in which hypocretin was directly administered to the brain, suggest that using hypocretin derivatives may be an effective way to prevent cataplexy and improve wakefulness.
In order to make a determination of narcolepsy, your primary care doctor will ask you for a complete medical and family history and may refer you to a sleep center for evaluation. You should keep a sleep diary as well as a record of your symptoms and their severity for at least a week or two. Bring this information with you when you visit your doctor.
Two different sleep studies will also be necessary for a diagnosis to be reached. The first is an overnight stay in the sleep lab. After this overnight visit, an additional study called a multiple sleep latency test (MSLT) will begin and will last into the afternoon. In this test, the time taken for you to fall asleep (sleep latency) during the day while lying in a quiet room is measured. You will take five scheduled naps every two hours. From the results of these two tests combined, a diagnosis can be made.
There is currently no widely-accepted cure for narcolepsy but symptoms can be alleviated to the point of near-normal functioning in many patients. Treatment for narcolepsy includes the use of medication as well as behavioral therapy. The goal in using medications to treat narcolepsy is to achieve normal alertness with minimal side effects.
Behavioral therapies may help control symptoms, including taking three or more scheduled naps throughout the day. Patients should also avoid heavy meals and alcohol, which can disturb or induce sleep.
Counseling is very important for people with narcolepsy. The particular symptoms of this disorder are not widely understood by the general public and this may cause patients to feel uncomfortable, alienated, or depressed. The disease can also be quite frightening and the fear of falling asleep inappropriately often significantly alters life for people with narcolepsy.
Behavior treatment of narcolepsy includes:
- Several short daily naps (10-15 minutes) to combat excessive sleepiness
- Establish a routine sleep schedule
- Maintain a regular exercise and meal schedule
- Avoid alcohol, caffeine, nicotine