Narcolepsy is a sleep disorder that affects about 1% of the world’s population and is characterized by successive sleep attacks or an irrepressible desire to sleep. Cataplexy, associated with this disorder, has the same consequence as narcolepsy but with a different reason: strong emotions such as laughing or crying cause a sudden loss of muscle tone that can range from something as light as drooping of the eyelids to the total collapse of the organism in which the individual falls to the ground suddenly; as if the muscles disconnected without warning.
It is a neurological problem for which there is no cure, but it can be controlled by specific medications and the modification of potential triggers (such as laughter or anger).
This sudden loss of muscle control, which usually occurs on both sides of the body, has a very common trigger: laughter , although it can also be caused simply by surprise, stress, happiness or any change in emotional state such as anger. .
The cataplexy attack can last from a few seconds to several minutes and the average is usually several attacks a week; however, there are cases of people who suffer several every day.
Although it is often associated with narcolepsy , it can also be caused by other rare diseases such as Niemann-Pick disease type C, Prader-Willi syndrome, and Wilson disease.
According to experts, cataplexy occurs as a result of a dissociation from REM sleep – when the muscles are at rest – in waking hours. A loss of hypocretin , a neurotransmitter involved in the regulation of the sleep / wake cycle is, apparently, the culprit or major driver of this disorder.
Symptoms
The cataplexy symptoms associated with narcolepsy often begin in childhood and adulthood, between the ages of 7 and 25 , but can begin at any time.
Symptoms of a cataplectic episode can include:
– facial twitching, blinking or grimacing
– unusual movements of the tongue
– jaw trembling
– dropping the head or jaw
– knee tremor
– Fallen eyelid
– difficulty speaking
Causes
As we have discussed, the REM sleep dissociation hypothesis suggests that cataplexy is muscle paralysis that normally occurs during REM sleep that enters waking hours. The exact underlying cause of this intrusion is unknown, but loss of hypocretin-producing neurons (also known as orexin) is thought to be a major contributing factor to these episodes. Hypocretin is a neurotransmitter involved in promoting wakefulness within the sleep / wake cycle.
Narcolepsy is believed to be an autoimmune disorder, but more research is needed.
A study published in the Journal of Clinical Investigation in 2010 revealed that hypocretin loss is caused by an autoimmune response directed at TRIB2 autoantigens. This autoimmune response causes trib 2 antibodies to form, which attack and destroy neurons in the brain that produce hypocretin.
The frequency of cataplectic episodes varies from less than one per year to several per day. On average, a person with cataplexy will experience one or more episodes each week.
Treatment and prevention
There is no cure for cataplexy , and treatment focuses on managing symptoms with good sleep hygiene practices and using medications as needed. In addition, safety measures must be taken to prevent serious injury from falls.
Good sleep hygiene practices include:
– maintain a consistent sleep schedule, which includes getting up and going to bed at the same time every day, even on weekends or during vacations
– strive to sleep 7 to 8 hours a day
– make the room calm and relaxing and keep it at a comfortable and cool temperature
– limit exposure to light in the evenings
– exercise regularly and maintain a healthy diet
– avoid eating a large meal before going to bed and opt for a light and healthy snack if necessary
– avoid caffeine in the late afternoon or evening
– avoid alcohol
– schedule one or more short naps during the day.
One of the medications that can help control symptoms is antidepressants. These include venlafaxine, a serotonin-norepinephrine reuptake inhibitor (SNRI) antidepressant, and tricyclic antidepressants such as clomipramine, imipramine, and desipramine. However, the evidence supporting the use of antidepressants for cataplexy is mixed.
