A study in a mouse model found that serum from narcolepsy patients was reactive with more than 86% of the hypocretin neurons in the mouse hypothalamus. High titers of Trib2-specific antibodies correlated with more severe cataplexy. In most cases of narcolepsy with cataplexy, and in some cases without cataplexy, sleep abnormalities result from a loss of certain brain cells in a part of the brain called the hypothalamus. These cells normally produce chemicals called hypocretins, which have many important functions in the body. It is unclear what causes the death of hypocretin-producing neurons in people with narcolepsy, although evidence increasingly points to an abnormality of the immune system. Affected individuals feel tired during the day, and several times a day they may experience an overwhelming need for sleep.
Therefore, researchers treated some people with narcolepsy with off-label clarithromycin, and most felt their symptoms improved with this treatment. To help determine whether clarithromycin is truly beneficial for treating narcolepsy and idiopathic hypersomnia, a small, double-blind, randomized, controlled clinical trial was completed in 2012. In many cases, regularly scheduled short naps can reduce the need for drug treatment of SDE, but only improve symptoms for a short period of time. A 120-minute nap provided benefits for 3 hours in the person’s alertness, while a 15-minute nap provided no benefit. Continuous communication between the caregiver, the person and their family members is important for optimal management of narcolepsy.
At different times throughout the day, people with narcolepsy experience fleeting urges to sleep. If the urge becomes overwhelming, people will fall asleep for periods of a few seconds to a few minutes. Groups of neurons in different parts of the brain work together to regulate sleep, and the activity of these neurons is controlled by a large number of genes. The loss of hypocretin-producing neurons in the hypothalamus is the leading cause of type 1 narcolepsy. When these neurons disappear, changes between wakefulness, REM sleep, and non-REM sleep can occur spontaneously. This results in sleep fragmentation and daytime symptoms experienced by people with narcolepsy.
Symptoms often include periods of excessive daytime sleepiness and brief episodes of involuntary sleep. About 70% of those affected also experience Cheap modafinil episodes of sudden loss of muscle strength, known as cataplexy. Narcolepsy in combination with cataplexy is proven to be an autoimmune disease.
The temporary inability to move or speak while falling asleep or waking up usually lasts only a few seconds or minutes and is similar to REM-induced inhibitions of voluntary muscle activity. Sleep paralysis is similar to cataplexy, except that it occurs at the edges of sleep. Even when severe cataplexy and sleep paralysis do not result in permanent dysfunction: after the end of the episodes, people quickly regain their full ability to move and speak. People can fall asleep involuntarily, even if they are in the middle of an activity, such as driving, eating, or talking. Those who have type 2 narcolepsy usually do not have cataplexy and have normal levels of hypocretin, but experience excessive daytime sleepiness. The destruction of hypocretin-producing neurons appears to be an autoimmune process.
Narcolepsy is a lifelong problem, but it usually doesn’t get worse as a person ages. Symptoms may partially improve over time, but they will never completely disappear. The most typical symptoms are excessive daytime sleepiness, cataplexy, sleep paralysis and hallucinations. Although everyone has excessive daytime sleepiness, only 10 to 25 percent of affected individuals will experience all other symptoms over the course of their illness.
Narcolepsy with cataplexy has been linked to low levels of a specific chemical in the brain called hypocretin. This chemical plays an important role in sleep regulation and other functions. Hypocretin also functions as a neurotransmitter, a chemical that alters, amplifies or transmits nerve impulses from one nerve cell to another, allowing nerve cells to communicate. Researchers have found that the number of neurons that produce hypocretin is significantly reduced in individuals with narcolepsy. Hypocretin-producing neurons are located in the hypothalamus, the area of the brain that regulates many functions, such as sleep, appetite and body temperature.
Polysomnography is used as part of this test to assess how quickly people fall asleep. It detects when people fall asleep and is used to monitor sleep stages during naps and to determine if REM sleep occurs. During multiple sleep latency tests, people with narcolepsy usually fall asleep quickly and have at least two REM naps. Doctors suspect narcolepsy when people with excessive daytime sleepiness have had episodes of muscle weakness. However, doctors can’t base the diagnosis on symptoms alone, as other conditions can cause some of the same symptoms. Sleep paralysis and similar hallucinations occasionally occur in healthy adults, in people with sleep deprivation, and in people with sleep apnea or depression.
“Sleep attacks” can occur at unusual times, such as during a meal or in the middle of a conversation. They last from a few seconds to a few minutes and often lead to a longer nap, after which affected individuals wake up feeling fresh. All people with narcolepsy have extreme levels of daytime sleepiness, but how this is displayed may differ. For example, some people with narcolepsy may fall asleep for 10 to 20 minutes several times a day, whether they like it or not.