Narcolepsy

Narcolepsy is a neurological sleep disorder characterized by an extreme tendency to fall asleep at any time in relaxing surroundings. Narcolepsy affects a person’s control over sleep and wakefulness. As a result, people with narcolepsy are excessively sleepy during the daytime. They experience uncontrollable episodes of falling asleep that can occur during any type of activity at any time of the day. People may unwillingly fall asleep while at work or at school, when having a conversation, playing a game, eating a meal, or even while driving.

In the typical sleep cycle we enter the early stages of sleep (NREM or non-rapid eye movement sleep), which is then followed by deeper sleep stages. After about 90 minutes we enter REM (rapid eye movement) sleep. For those who suffer from narcolepsy, REM sleep occurs almost immediately in the sleep cycle, rather than after the first few stages, as well as periodically during the waking hours. REM sleep is when dreams and sometimes muscle paralysis occurs, explaining some of the symptoms of narcolepsy.

Narcolepsy usually begins between the ages of 15 and 25. However in many cases it goes undiagnosed, therefore untreated. The condition is life-long. Narcolepsy is an under-recognized and under-diagnosed condition and is estimated to affect one in every 3,000 Americans.

It has been found that most people with narcolepsy have low levels of the neurotransmitter Hypocretin, which promotes wakefulness, explaining the increased tendency to fall asleep sporadically. (Neurotransmitters are chemicals that neurons produce to communicate with each other and regulate biological processes.)

 

Most cases of narcolepsy are random, as it can occur in anyone even if they have no family history of the disorder. However, up to 10% of narcolepsy patients have reported having a close relative with similar symptoms. In addition other factors such as environmental stress and triggers could be somehow related to the diagnosis of narcolepsy.

Symptoms of Narcolepsy include:

Excessive Daytime Sleepiness (EDS):

  • This is usually the first symptom to become apparent as it interferes with the ability to perform normal activities on a daily basis.
  • It results in mental cloudiness, lack of energy, reduced concentration, memory lapse, depressed mood and sometimes extreme exhaustion.
  • Involuntary sleep episodes occur as a result of this, meaning that the patient will suddenly fall asleep for a few short minutes, randomly during the day.
  • During these episodes, people are usually engaged in habitual, “second nature” activities such as taking notes in class, typing or driving. They can’t remember what they were doing and their performance is almost always impaired.
  • For example their handwriting could become impaired or they may forget where they’ve put their keys, etc. 

Cataplexy:

  • This is a sudden loss of muscle tone that leads to feelings of weakness and a loss of voluntary muscle control.
  • Attacks can occur at any time with patients experiencing this symptom several weeks or months after the onset of early daytime sleepiness.
  • It can cause symptoms such as slurred speech and total body collapse and is mostly triggered by strong emotions such as surprise, fear, laughter and anger.
  • The loss of muscle tone during a cataplectic episode resembles the interruption of muscle activity that naturally occurs during REM sleep, explaining why the symptom occurs.

Hallucinations:

  • Hallucinations can accompany sleep paralysis and occur when people are falling asleep, awake or during sleep.
  • Images are unusually vivid, seem real and can be frightening. Most often the content is primarily visual but any of the other senses can be involved.
  • Hypnagogic hallucinations are when they accompany sleep.
  • Hypnopompic hallucinations are when they occur when the patient is awake.

Sleep Paralysis:

  • This is the temporary inability to move or speak while falling asleep or waking up.
  • This stage often goes unnoticed by people who experience normal sleep because it occurs only when they are fully asleep and entering the REM stage at the appropriate time in the sleep cycle.
  • The episodes are brief, ranging from a few seconds to several minutes and after they end the patient recovers full capacity to move and speak.

Disrupted Nocturnal Sleep:

  • While individuals with narcolepsy have no difficulties falling asleep at night, they can experience difficulties staying asleep.
  • They can experience insomnia, vivid dreaming, sleep talking, acting out while dreaming and periodic leg movements.

These symptoms can be extremely dangerous and severely affect the person’s quality of life as they inhibit daily activities.

Treatment:

While there is no cure for narcolepsy, several medications can help with the severity of some of the symptoms.

Medication:

Modafinil and Sodium Oxybate are currently FDA approved for treatment. Central nervous system alerting agents such as Modafinil reduce the incidence of sleep attacks. Two classes of antidepressants, Tricyclics and Selective Seretonin and Noradrenergic Reuptake Inhibitors have also been proven effective in controlling cataplexy. Sodium oxybate, a strong sedative taken at night, induces sleep and reduces the symptoms of daytime sleepiness and cataplexy. Due to safety concerns the distribution of sodium oxybate is tightly restricted.

Medications are generally quite effective at reducing daytime drowsiness and improving levels of alertness. However, use of these medications may be associated with several undesirable side effects and must be carefully monitored.

 

Less common than medication, behavioral therapy can also be used in the treatment of narcolepsy. Symptoms can be controlled by taking three or more scheduled naps throughout the day and avoiding heavy meals and alcohol. Counseling is also very important, as most symptoms of narcolepsy are not widely understood by the general public. The disease can also be quite frightening and the fear of falling asleep inappropriately is difficult to cope with for people with narcolepsy.

Sources:

http://www.webmd.com/sleep-disorders/guide/narcolepsy

http://www.ninds.nih.gov/disorders/narcolepsy/detail_narcolepsy.htm

https://sleepfoundation.org/sleep-disorders-problems/narcolepsy-and-sleep

Written by: Subhaga Laxman