Narcolepsy and Sleep
Narcolepsy is a neurological disorder caused by the brain's inability to regulate sleep-wake cycles normally. 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. 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.
In order to understand the basics of narcolepsy, it is important to first review the features of "normal sleep." Sleep happens in cycles. When we fall asleep, we initially enter a light stage of sleep and then progress into increasingly deeper stages. Both light and deep sleep stages are called non-REM (rapid eye movement) sleep. After about 90 minutes, we enter the first stage of REM sleep, which is the dreaming portion of sleep, and throughout the night we alternate between stages of REM and non-REM sleep. For people with narcolepsy, sleep begins almost immediately with REM sleep and fragments of REM occur involuntarily throughout the waking hours. When you consider that during REM sleep our muscles are paralyzed and dreaming occurs, it is not surprising that narcolepsy is associated with paralysis, hallucinations, and other dream-like and dramatically debilitating symptoms.
Despite the perception that people with narcolepsy are perpetually sleepy, they do not typically sleep more than the average person. Narcolepsy is considered a "state boundary" control abnormality. That is, narcolepsy patients sleep a normal amount but cannot control the timing of sleep.
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.
Narcolepsy patients typically endure many years of daytime sleepiness before seeking treatment because sleepiness is not indicative of disease to most people. Yet the devastating potential of this disorder is reflected in studies showing that narcoleptic patients are more accident-prone and have difficulty with interpersonal relationships.
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.
The main symptoms associated with narcolepsy are:
- 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.
In order to make a determination of narcolepsy, your 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.
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.
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.
In treating narcolepsy, doctors typically prescribe stimulants to improve alertness and diminish excessive daytime sleepiness. Antidepressants are also often used to treat cataplexy, hypnagogic hallucinations and sleep paralysis. Finally, sodium oxybate, a strong sleep-inducing agent, may be given at night to improve disturbed nocturnal sleep and reduce daytime sleepiness and cataplexy. All these treatments may have side effects. Stimulants can cause headaches, irritability, mood changes, nervousness, insomnia, anorexia, and irregular heartbeat. Side effects from the use of antidepressants vary and can include nausea, weight gain, anxiety or decreased emotions, drowsiness, sexual dysfunction and changes in blood pressure. Sodium oxybate can induce nausea, excessive sedation, mood changes and enuresis.
The goal in using medications to treat narcolepsy is to achieve normal alertness with minimal side effects.
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
Reviewed by Emmanuel Mignot, MD, PhD.