Neuromyelitis optica spectrum disorder (NMO) is a rare inflammatory disease of the central nervous system (eye nerves, spinal cord, and brain). NMO may also be called neuromyelitis optica or NMO.1
NMO is a demyelinating disorder. Myelin is the protective coating that surrounds the nerve fibers in your brain, spinal cord, and eye. Damage to the myelin layer is called demyelination. Demyelination causes nerve signals to slow or stop, leading to brain and nerve problems.1,2
NMO is also an autoimmune disorder. This means the immune system cannot tell the difference between healthy cells and invaders like viruses, fungi, or bacteria. Because the body cannot tell the difference, it begins to attack and damage healthy cells.
The symptoms of NMO can be different depending on which part of the body is affected. Symptoms also vary in severity and how long they last. Several types of sleep problems may occur with NMO.3
How NMO impacts sleep
Antibodies are chemicals the immune system makes to kill germs. In some diseases, antibodies can also be harmful. One antibody that is common in NMO attacks a protein called aquaporin-4 (AQP4). AQP4 antibodies (AQP4-IgG) cause inflammation and damage in the brain, spinal cord, and eye nerve (optic nerve).4,5
NMO and sleep have a complicated relationship. Electrical activity and hormones in the brain maintain a delicate balance that causes the body to sleep and wake. Anything that upsets this balance can lead to sleep problems. The most common sleep problems in people with NMO are:6
- Poor sleep quality
- Narcolepsy
- Periodic limb movement disorder
- Restless legs syndrome
- Sleep apnea
The exact reason why sleep problems are common in NMO is not known. Doctors think several factors may be at play, including:6
- Damage to the brain and spinal cord (brain lesions)
- Weakness of the diaphragm, which is an important muscle for breathing
- Side effects from drugs used to treat NMO
- Chronic (long-term) pain
Narcolepsy
Narcolepsy is a sleep disorder in which someone falls asleep without meaning to, often several times a day. This may occur in the middle of an activity such as driving, eating, working, or talking. Some people with narcolepsy go limp or lose muscle tone following a strong emotion such as laughter. This is called cataplexy.1
People with NMO can have type 1 narcolepsy. Most people with type 1 narcolepsy have low levels of the brain hormone hypocretin. NMO may cause brain lesions, which is a type of brain tissue damage. These lesions are thought to decrease hypocretin levels, which leads to narcolepsy.1
The most common symptoms of narcolepsy are:1
- Excessive daytime sleepiness
- Cataplexy
- Sleep paralysis
- Hallucinations
Other symptoms of narcolepsy include insomnia, fragmented sleep, and automatic behaviors. Automatic behavior means the person continues a complex task such as driving while asleep. They often cannot remember what they did once they wake up.1
Sleep apnea
Sleep apnea is a sleep disorder in which breathing is interrupted for several seconds or longer during sleep. People with sleep apnea tend to snore loudly and make gasping or choking noises in their sleep.4
Sleep apnea causes low oxygen levels in the blood and poor sleep. Left untreated, it can lead to high blood pressure, heart disease, diabetes, kidney disease, depression, and more. Using a continuous positive airway pressure (CPAP) machine reduces the risk of other health conditions linked to sleep apnea and improves sleep quality.4
PLMD
In general, restless legs syndrome (RLS) happens when the person is awake (typically when trying to fall asleep), while periodic limb movement disorder (PLMD) happens during sleep. RLS can be felt by the person but not seen by others. With PLMD, the legs, and in some cases arms, twitch or jerk every 15 to 40 seconds, sometimes all night. PLMD is also common in NMO.7
Treatment for sleep disorders
It is important to talk with your doctor about any sleep problems you may have. Sleep disorders are often treatable.
There are many options to treat sleep disorders. The treatment will depend on the type of sleep issues you have. For instance, sleep apnea is usually treated with a CPAP machine. Restless legs syndrome may be treated by changing your medicines or adding iron supplements.
Narcolepsy cannot be cured, but it can be controlled with medicine and short daytime naps. Several drugs can help improve the symptoms of narcolepsy, including:8,9
- Stimulants such as Provigil® (modafinil), Adderall® (amphetamines), and Ritalin® (methylphenidate)
- Certain antidepressants
- Sodium oxybate (also known as gamma hydroxybutyrate or GHB)
- Wakix® (pilotisant)
- Sunosi® (solriamfetol)
However, one of the most effective and helpful treatments requires no machines or pills. It is called sleep hygiene. This is simply a series of lifestyle habits that make it easier to get good quality sleep. Good sleep hygiene practices include:10
- Going to sleep at the same time each night
- Making sure the room you sleep in is dark and quiet
- Limiting the use of electronics and stopping any work in the hours before you go to sleep
- Limiting caffeine
Along with sleep disorders, other complications may also occur with NMO. These include:
- Rapid weight loss
- Depression and anxiety
- Fatigue (tiredness)
- Breathing problems
