Sleep disorders are common and can have a significant impact on an individual's quality of life. Narcolepsy and sleep paralysis are two examples of sleep disorders that can affect an individual's ability to function during the day. Narcolepsy is a chronic neurological disorder that affects the brain's ability to regulate sleep-wake cycles, while sleep paralysis is a condition where an individual is unable to move or speak upon waking up despite being fully conscious.
Definition and causes of narcolepsy
Narcolepsy is a chronic neurological disorder that affects the brain's ability to regulate sleep-wake cycles. It is caused by a deficiency in the brain chemical hypocretin, which is responsible for promoting wakefulness. The exact cause of hypocretin deficiency is unknown, although it is believed to be the result of an autoimmune disorder that destroys the cells that produce hypocretin.1
Symptoms of narcolepsy
Excessive daytime sleepiness (EDS)
Excessive daytime sleepiness is the most common symptom of narcolepsy. Individuals with narcolepsy often feel sleepy or tired throughout the day, regardless of how much sleep they get at night. They may fall asleep at inappropriate or often dangerous times, such as during a conversation, while driving, or working.
A sleep attack is an overwhelming urge to sleep that can occur at any time during the day. During a sleep attack, an individual with narcolepsy may suddenly fall asleep without warning. These sleep attacks can last for a few seconds to several minutes.
Cataplexy is a sudden loss of muscle tone that is often triggered by strong emotions such as laughter, anger, or surprise. During an episode of cataplexy, an individual with narcolepsy may experience slurred speech, drooping eyelids, or weakness in their arms or legs.
Hypnagogic hallucinations are vivid and often frightening hallucinations that occur during the transition between wakefulness and sleep. These hallucinations can be visual, auditory, or tactile and can last for a few seconds to several minutes.
Sleep paralysis is a condition where an individual is unable to move or speak upon waking up despite being fully conscious. It is often associated with narcolepsy, although it can occur independently as well.
Definition and causes of sleep paralysis
Sleep paralysis is a type of parasomnia when you can not move your muscles as you wake up or fall asleep. It is an abnormal behaviour that occurs during the rapid eye movement (REM) stage of sleep. Sleep paralysis typically lasts for a few seconds to a few minutes and can be a frightening experience. It is thought to occur when the brain and body are not synchronized during the transitions between sleep stages.
The exact causes of sleep paralysis are not fully understood and known. However, it is believed to be associated with several factors, including genetics, disrupted sleep patterns, and changes in the brain's chemical balance. It may also occur in people who have narcolepsy.3,4
Symptoms of sleep paralysis
The primary symptom of sleep paralysis is being unable to move or speak while falling asleep or waking up. These symptoms typically last for a few seconds to a few minutes and can be very frightening for those experiencing them. Other common symptoms include:
- A feeling of pressure or weight on the chest
- Inability to Move or Speak: During sleep paralysis, a person is unable to move their body or speak. This is due to the continued muscle paralysis that occurs during the REM stage of sleep. Although the person is conscious and aware of their surroundings, they are temporarily unable to move or speak
- Hallucinations: Many people with sleep paralysis also experience hallucinations. These can take many forms, including visual, auditory, or tactile hallucinations. Common hallucinations during sleep paralysis include the feeling of being touched, the presence of a threatening figure, or hearing voices
- Fear or Anxiety: Sleep paralysis can be a very frightening experience, and many people experience feelings of fear or anxiety during an episode. This can be due to the hallucinations experienced during sleep paralysis, as well as the inability to move or speak
Differences between sleep paralysis and narcolepsy-related sleep paralysis
While sleep paralysis can occur in people with narcolepsy, there are some differences between sleep paralysis and narcolepsy-related sleep paralysis.
Typically, when a person falls asleep, they enter the non-rapid eye movement phase (NREM), during which the brain wave gradually slows down, and after 60 to 90 minutes, they enter the REM phase. There are three stages of NREM, followed by REM, and these together make one sleep cycle. Normally, a person will go through four or five cycles per night.
The REM phase is when you dream, and the body goes into paralysis so that you do not act out your dream physically. Mostly, the person would never realize the paralysis, but in some cases, when you are awake between the transition from one cycle to another, you might experience sleep paralysis.
If you have narcolepsy, you might miss NREM and enter REM in just 15 minutes of falling asleep. Researchers believe that sleep paralysis occurs more frequently in those with narcolepsy than the general population because of these REM timing abnormalities, meaning a person’s brain starts or remains in REM, even when the person is awake.
The diagnosis of narcolepsy and sleep paralysis is based on clinical evaluation and supported by objective testing. The stages of the diagnostic process include: 5,6
Medical history and physical examination
A thorough medical history and physical examination by a healthcare professional. The healthcare provider will inquire about the patient's symptoms, sleep patterns, medical history, and family history of sleep disorders.
Tests for narcolepsy and sleep paralysis
After the initial evaluation, the healthcare provider may refer the patient for additional testing. The most commonly used tests for narcolepsy are the multiple sleep latency test (MSLT) and the polysomnogram (PSG) with a nocturnal video recording. MSLT measures the patient's ability to fall asleep and enter into rapid eye movement (REM) sleep during the day. PSG, with a nocturnal video recording, measures the number and duration of sleep cycles, including REM sleep.
For sleep paralysis, a sleep study or polysomnogram may also be performed. During the sleep study, the patient's brain activity, breathing, and body movements are monitored. The healthcare provider may also order blood tests to rule out other underlying conditions that can cause similar symptoms, such as thyroid dysfunction.
When considering a potential diagnosis of narcolepsy or sleep paralysis, it's important to keep in mind that other conditions can cause similar symptoms, particularly if cataplexy isn't present. For example, many different factors can contribute to excessive daytime sleepiness, such as sleep deprivation, sleep apnea, mood disorders, and circadian rhythm sleep-wake disorders. To determine the cause of daytime sleepiness, doctors may use sleep logs and actigraphy, and in cases where circadian disorders are suspected, multiple sleep latency tests (MSLT) can help identify sleep-onset REM periods (SOREMPs)
Treatment and management
Although there is no cure for narcolepsy and sleep paralysis, several treatment options can help manage symptoms. Some of them include:5,6
Medications for narcolepsy and sleep paralysis
The most commonly used medications for narcolepsy and sleep paralysis are stimulants, such as modafinil and armodafinil, which help reduce daytime sleepiness. Sodium oxybate, a central nervous system depressant, can help manage cataplexy and improve nighttime sleep. Antidepressants, such as selective serotonin reuptake inhibitors (SSRIs), can also help reduce cataplexy episodes and improve mood.
Lifestyle changes to manage symptoms
In addition to medication, several lifestyle changes can help manage symptoms of narcolepsy and sleep paralysis. Establishing a regular sleep routine, avoiding alcohol and caffeine, and maintaining a healthy diet and exercise regimen can help improve sleep quality and reduce daytime sleepiness.
Coping strategies for sleep paralysis
For individuals with sleep paralysis, several coping strategies can help reduce anxiety and prevent future episodes. These strategies include maintaining a regular sleep schedule, reducing stress levels, and avoiding sleeping on one's back, as it can increase the likelihood of sleep paralysis.
Narcolepsy is a chronic neurological disorder that affects the brain's ability to regulate sleep-wake cycles, while sleep paralysis is a condition where an individual is unable to move or speak upon waking up despite being fully conscious. Sleep paralysis occurs more frequently in those with narcolepsy than in the general population because of REM timing abnormalities. Narcolepsy and sleep paralysis require a proper diagnosis and treatment plan. Healthcare professionals can provide accurate diagnoses and guide treatment plans to manage symptoms effectively. A combination of medication and lifestyle changes can help manage symptoms and improve the quality of life for individuals with narcolepsy and sleep paralysis.
- Dauvilliers Y, Arnulf I, Mignot E. Narcolepsy with cataplexy. The Lancet [Internet]. 2007 Feb [cited 2023 Dec 8];369(9560):499–511. Available from: https://linkinghub.elsevier.com/retrieve/pii/S0140673607602372
- Narcolepsy | national institute of neurological disorders and stroke [Internet]. [cited 2023 Dec 8]. Available from: https://www.ninds.nih.gov/health-information/disorders/narcolepsy
- Sateia MJ. International classification of sleep disorders-third edition. Chest [Internet]. 2014 Nov [cited 2023 Dec 8];146(5):1387–94. Available from: https://linkinghub.elsevier.com/retrieve/pii/S0012369215524070
- Sharpless BA, Kliková M. Clinical features of isolated sleep paralysis. Sleep Medicine [Internet]. 2019 Jun 1 [cited 2023 Dec 8];58:102–6. Available from: https://www.sciencedirect.com/science/article/pii/S1389945718308311
- Ahmed I, Thorpy M. Clinical features, diagnosis and treatment of narcolepsy. Clinics in Chest Medicine [Internet]. 2010 Jun [cited 2023 Dec 8];31(2):371–81. Available from: https://linkinghub.elsevier.com/retrieve/pii/S0272523110000377
- An American Academy of Sleep Medicine Review, Wise MS, Arand DL, Auger RR, Brooks SN, Watson NF. Treatment of narcolepsy and other hypersomnias of central origin. Sleep [Internet]. 2007 Dec 1 [cited 2023 Dec 8];30(12):1712–27. Available from: https://academic.oup.com/sleep/article/30/12/1712/2696925