What is Narcolepsy?
Narcolepsy is a neurological disorder that affects the control of sleep and wakefulness. It is characterized by slippage between 2 states of being: wake and REM sleep. People with narcolepsy experience excessive daytime sleepiness and intermittent, uncontrollable episodes of falling asleep during the day usually every 2-3 hours. These sudden sleep attacks may occur during any type of activity at any time of day.
Many narcolepsy patients are diagnosed, usually erroneously with psychiatric disorders such as depression, malingering, or even schizophrenia. In many cases, narcolepsy is undiagnosed and, therefore, untreated.
What causes Narcolepsy?
The cause of narcolepsy is not known; however, it results in a loss of neurons in the brain that produce a chemical called hypocretin. Hypocretin is a neurotransmitter and is thought to be a wake-promoting agent. In addition, researchers have discovered abnormalities in various parts of the brain involved in regulating sleep which seem to contribute to symptom development.
It is likely narcolepsy involves multiple factors that interact to cause neurological dysfunction and sleep disturbances.
What are the symptoms of Narcolepsy?
Symptoms of narcolepsy include:
- Excessive daytime sleepiness (EDS)
This symptom is the sinequanon of narcolepsy. In general, EDS interferes with normal activities on a daily basis, whether or not a person with narcolepsy has sufficient sleep at night. People with EDS report mental cloudiness, a lack of energy and concentration, memory lapses, a depressed mood, and/or extreme exhaustion. Furthermore, people with narcolepsy have actual sleep attacks many times during the day.
This symptom consists of a sudden loss of muscle tone that leads to feelings of weakness and a loss of voluntary muscle control. It can cause symptoms ranging from slurred speech to total body collapse depending on the muscles involved and is often triggered by intense emotion, for example surprise, laughter or anger. Click this link to watch Rusty, the narcoleptic dog >>
Usually, these delusional experiences are vivid and frequently they are frightening. They occur as the person is falling asleep or just waking up and likely represent REM intrusion with dream mentation. The content is primarily visual, but any of the other senses can be involved.
- Sleep paralysis
This symptom involves the temporary inability to move or speak while falling asleep or waking up which is very frightening to the patient. These episodes are generally brief lasting a few seconds to several minutes. After episodes end, people rapidly recover their full capacity to move and speak.
Narcolepsy: Who is affected?
The peak age at which symptoms occur is 15-25 years. A second smaller peak of onset has been noted between 35-45 years, and near menopause in women.
Narcolepsy: How is it diagnosed?
Sometimes, the diagnosis of Narcolepsy is fairly apparent from the patient’s complaints, especially if the patient or a family member describes cataplexy which is a phenomenon unique to narcolepsy. Still, the American Academy of Sleep Medicine recommends that the diagnostic work-up for Narcolepsy include an overnight sleep study (polysomnogram) followed by a Multiple Sleep Latency Test, which is a daytime nap study that attempts to quantify daytime sleepiness and document a shortened REM latency which means REM occurs very shortly after falling asleep. In rare cases, cerebro-spinal fluid is taken from the patient via a lumbar puncture in order to analyze the levels of Hypocretin (AKA Orexin) which are typically very low and undetectable in patients with Narcolepsy. Even less often, a genetic test can be run. This is rarely considered to impart additional information, because a large percentage of patients without Narcolepsy have the same biologic markers.
How is it treated?
There are medications that can be quite effective and can help people with narcolepsy lead normal lives. Stimulants such as Modafanil (Provigil) are used to improve day time alrtness and hypnotics such as sodium oxybate (Xyrem) are used to consolidate sleep. Sodium Oxybate is also effective at treating Cataplexy. Other medications useful for treating Cataplexy are anti-depressants such as SSRIs (Serotonin selective re-uptake inhibitors).