Narcolepsy
A chronic sleep disorder that causes overwhelming daytime drowsiness.
Sometimes, narcolepsy can be accompanied by a sudden loss of muscle tone(Cataplexy), which can be triggered by strong emotions. Narcolepsy that occurs with cataplexy is called type 1 narcolepsy. Narcolepsy that occurs without cataplexy is known as type 2 narcolepsy.
Narcolepsy is a neurological disorder that affects your ability to wake and sleep. People with narcolepsy have excessive, uncontrollable daytime sleepiness. They may also suddenly fall asleep at any time, during any type of activity. In a typical sleep cycle, we enter the early stages of sleep, then the deeper states, and finally after about 90 minutes of rapid eye movement (REM) sleep. People with narcolepsy go into REM sleep almost immediately in the sleep cycle and sometimes while awake.
Type 1 narcolepsy comes with a sudden loss of muscle tone that causes weakness and makes you unable to control your muscles(cataplexy). Type 2 is narcolepsy without cataplexy.
Causes:
The exact cause of narcolepsy is unknown. People with type 1 narcolepsy have low levels of the chemical hypocretin. Hypocretin is an important neurochemical in your brain that helps regulate wakefulness and REM sleep.
Hypocretin levels are particularly low in those who experience cataplexy. Exactly what causes the loss of hypocretin-producing cells in the brain isn't known, but experts suspect it's due to an autoimmune reaction. It's also likely that genetics play a role in the development of narcolepsy, but the risk of a parent passing this disorder to a child is very low only about 1%.
Research also indicates a possible association between exposure to the swine flu (H1N1 FLU) virus and a certain form of H1N1 vaccine that's currently administered in Europe, though it's not yet clear why.
Symptoms of Narcolepsy:
Those symptoms may include:
Excessive daytime sleepiness(EDS):
In general, EDS makes it harder to do everyday activities, even if you got enough sleep at night. You have memory lapses and feel depressed or exhausted.
Cataplexy:
This can cause problems ranging from slurred speech to total body collapse, depending on the muscle involved. It's often triggered by intense emotions such as surprise, laughter, or anger.
Hallucinations:
These delusions can happen at any time and are often vivid and frightening. They're mostly visual, but any of the other senses can be involved. If they happen as you're falling asleep, they're called hypnagogic hallucinations. If they happen when you're waking up, they're called hypnopompic hallucinations.
Sleep Paralysis:
You may be unable to move or speak while falling asleep or waking up. These episodes usually last a few seconds to several minutes.
Disrupted sleep:
You might have a hard time staying asleep at night because of things like vivid dreams, breathing, problems, or body movements.
Some people with narcolepsy also have related problems, including:
- Periodic limb movement disorder (PLMD):
Your leg muscles move without your control many times during the night.
- Sleep apnea:
Your breathing often stops and starts while you sleep.
Automatic behavior:
You fall asleep during a regular activity like driving, walking, or talking. You continue the activity while asleep and wake up with no memory of what you did.
Narcolepsy Diagnosis:
Symptoms of narcolepsy can look like those of other health problems. Your diagnosis might involve:
- Physical exam and medical history:
Sleep records:
Your doctor might ask you to keep track of your symptoms and when you're sleeping for a couple of weeks.
Polysomnogram(PSG):
This is done in a sleep disorder clinic or a sleep lab. It's an overnight test that takes constant measurements while you're asleep to record problems in your sleep cycle. A PSG can help reveal whether you go into REM sleep at unusual times in your sleep cycle. It can rule out other problems that might be causing your symptoms.
Multiple sleep latency test(MSLT):
This is also done at a special clinic or lab. The test takes place during the day to measure your tendency to fall asleep and find out whether certain elements of REM sleep happen at unusual times furin the day. You'll take four or five short naps, usually 2 hours apart.
Other Characteristics:
People with narcolepsy may have other sleep disorders, such as obstructive sleep apnea a condition in which breathing starts and stops throughout the night, restless legs syndrome, and even insomnia.
Some people with narcolepsy experience automatic behavior during brief episodes of narcolepsy. For example, you may fall asleep while performing a task you normally perform, such as writing, typing, or driving, and you continue to perform that task while asleep. When you awaken, you can't remember what you did, and you probably didn't do it well.
Normal sleep pattern VS. Narcolepsy:
The normal process of falling asleep begins with a phase of non-rapid eye movement (NREM) sleep. During this phase, your brain waves slow considerably. After an hour or so of NREM sleep. Your brain activity changes and REM sleep begins, most dreaming occurs during REM sleep.
In narcolepsy, however, you may suddenly enter into REM sleep without first experiencing NREM sleep, both at night and during the day. Some of the characteristics of narcolepsy, such as cataplexy, sleep paralysis, and hallucinations, are similar to changes that occur in REM sleep, but occur during wakefulness or drowsiness.
Risk Factors:
There are only a few known risk factors for narcolepsy, including:
- Age: Narcolepsy typically in people between 10 to 30 years old.
- Family history: Your risk of narcolepsy is 20 to 40 times higher if you have a family member who has narcolepsy.
Complications:
Public misunderstanding of the condition:
Narcolepsy may cause serious problems for you professionally and personally. Others might see you as lazy or lethargic. Your performance may suffer at school or work.
Interference with intimate relationships:
Intense feelings, such as anger or joy, can trigger signs of narcolepsy such as anger or joy, can trigger signs of narcolepsy such as cataplexy, causing affected people to withdraw from emotional interactions.
Physical harm:
Sleep attacks may result in physical harm to people with narcolepsy, you're at increased risk of a car accident if you have an attack while driving. Your risk of cuts or burns is greater if you fall asleep while preparing food.
Obesity:
People with narcolepsy are more likely to be overweight. The weight gain may be related to low metabolism.
