Sudden loss of muscle tone

Everything you need to know about cataplexy

There is no cure for cataplexy, and treatment is symptom management with good sleep hygiene practices and the use of medication as necessary.

Additionally, safety measures should be put in place to avoid serious injury that can result from falls.

Good sleep hygiene practices include:

  • keeping a consistent sleep schedule, including getting up and going to bed at the same time every day, even on weekends or during vacations
  • striving for at least 7 to 8 hours of sleep, or the amount that normally makes you feel refreshed
  • making the bedroom quiet and relaxing and keeping it at a comfortable, cool temperature
  • limiting exposure to light in the evenings
  • exercising regularly and maintaining a healthful diet
  • avoiding a large meal before bedtime and opting for a light, healthful snack if necessary
  • avoiding caffeine in the late afternoon or evening
  • avoiding alcohol
  • scheduling one or more short naps during the day.

Sodium oxybate at doses between 6 and 9 grams (g) nightly is the medication approved by the U.S. Food and Drug Administration (FDA) for the treatment of cataplexy. Sodium oxybate is effective in reducing both the frequency and intensity of attacks.

Possible adverse effects are dizziness, headache, and nausea. This medication should not be used in conjunction with alcohol or any other central nervous system (CNS) depressant due to the risk of respiratory depression and other significant CNS depressant effects.

Other medications that may help control symptoms are antidepressants. These include venlafaxine, a serotonin-noradrenaline reuptake inhibitor (SNRI) antidepressant, and tricyclic antidepressants such as clomipramine, imipramine, and desipramine.

However, evidence supporting the use of antidepressants for cataplexy is varied. In addition, abrupt withdrawal of venlafaxine can potentially cause rebound cataplexy.

In regards to safety, even if an individual senses the onset of an episode, injury is very possible with cataplexy.

To help avoid injury from occurring with cataplexy:

Share on PinterestInjury can occur if a person falls suddenly.

  • Assess for and be aware of potential dangers such as glass, sharp edges, and heights.
  • Practice relaxation and stress management techniques.
  • Avoid sleep deprivation.
  • Avoid situations that are likely to evoke strong emotions, or prepare ahead of time by sitting down or having a companion nearby.
  • Do not drive a car or operate heavy machinery until cleared by a medical provider.
  • Enlist the help of significant others and friends, and educate them on the seriousness of the disorder.

Cataplexy is a transient, sudden loss of voluntary muscle control brought on by a strong emotional trigger such as laughing or excitement. Cataplexy is almost always associated with narcolepsy.

There is no cure, but education, sleep hygiene practices, and prescription medication can help people with this condition enjoy a better quality of life.

Cataplexy: Everything You Need to Know About This Narcolepsy Symptom

Understanding REM sleep — specifically, the way that sleep cycles are disrupted in people with narcolepsy — may help us gain insight into why cataplexy happens in people with narcolepsy. In normal sleep cycles, people go through three stages of non-rapid eye movement (NREM) sleep before entering the REM phase. Each cycle takes about 60 to 90 minutes before repeating throughout the night. But these cycles malfunction in people with narcolepsy. They may enter REM sleep right away when they fall asleep, and then wake up, bypassing the NREM stage; this can occur both during the night as well as the day, blurring the lines between wakefulness and sleep. (9,10)

RELATED: What’s Happening in the Brain During the Stages of Sleep

Another important point: The REM stage of sleep is when dreaming occurs, and when our bodies become paralyzed — a mechanism that is thought to prevents us from acting out our dreams and harming ourselves. In people with narcolepsy, this sleep paralysis associated with REM sleep happens at the wrong time, too, which is why sleep paralysis and vivid hallucinations while falling asleep or waking up can also occur. (11)

Cataplexy episodes resemble that loss of muscle control that naturally happens during REM sleep — but occur when someone is awake rather than during sleep.

Research published in September 2012 in the Journal of Neuroscience suggested that in healthy individuals, positive emotions may lead to muscle weakness (feeling weak with laughter, for instance), but that the brain chemical hypocretin (the one absent in people with narcolepsy) prevents that loss of muscle tone from being anything more than a brief event. (12)

This may help explain why, in people who have narcolepsy with cataplexy, that response is more extreme. More research needs to be done to better understand why and how strong emotions trigger this response to begin with, but recent and continuing discoveries into the role of hypocretin in narcolepsy are significant.

Isolated Cataplexy in the Differential Diagnosis of Drop Attacks: A Case of Successful Clinical Diagnosis and Treatment


Drop attacks are sudden spontaneous falls that are not accompanied by alteration of consciousness and are followed by immediate recovery. Cataplexy, which is usually associated with narcolepsy, is one of the causes of drop attacks. We report a patient with the rare condition of cataplexy without associated narcolepsy (isolated cataplexy). Isolated cataplexy should be included in the differential diagnosis when a patient presents with recurrent drop attacks and normal diagnostic test results.

1. Introduction

Drop attacks (DAs) are spontaneous falls that are followed by quick recovery. In patients with syncope, DAs are associated with transient loss of consciousness. Causes of syncope include arrhythmias, aortic stenosis, orthostatic hypotension, neurally mediated syncope, subclavian steal, and other disorders. These conditions can also cause episodes of presyncope in which patients experience DA with lightheadedness rather than loss of consciousness. The evaluation of these patients includes history, physical examination, and 12-lead electrocardiography, supplemented when warranted by echocardiography, tilt table testing, stress testing, and event recordings.

Falls may also result from seizures. If there is clinical suspicion of epilepsy, brain imaging and electroencephalogram (EEG) are useful diagnostic tools. Absence of epileptogenic activity during an attack suggests nonepileptic origin, but a normal interictal EEG does not rule out epilepsy. Also, patients with vertigo can be subject to falls. It is important to distinguish between sensations of lightheadedness and spinning (vertigo). The presence of vertigo is suggestive of a vestibulopathy or central nervous system process.

Occasionally, recurrent falls occur without alteration of consciousness. In the majority (64%) of these cases, the etiology of DA is not clearly established . Conversion reaction may simulate a drop attack and can be inferred by the exclusion of neurological disease, the exclusion of feigning, and determination of a psychological mechanism. A patient presenting with acute recurrent falls without alteration of consciousness and with unremarkable cardiac, neurological, and electrophysiological testing should prompt consideration of cataplexy and narcolepsy.

The term cataplexy is derived from the Latin word cataplessa (to strike down with fear or the like) and Greek kata-plexis (down-stroke). Henneberg (1916) named cataplexy, while Gelineau named narcolepsy (1880) . Cataplexy is most often associated with narcolepsy (excessive daytime sleepiness) as a major component of the narcolepsy tetrad that also includes sleep paralysis and hypnagogic hallucinations. The International Classification of Sleep Disorders-2 considers cataplexy as the hallmark symptom of the narcolepsy syndrome . Excessive daytime sleepiness is usually (but not always) the first symptom to appear, while cataplexy may be delayed in onset 1–30 years. Isolated cataplexy without associated narcolepsy has been reported with genetic associations .

The following case describes pitfalls in the diagnosis and management of a patient with clinically defined isolated cataplexy.

2. A Case Report

An 18 year-old right-handed female presented for neurological evaluation 9 months after the onset of recurrent DA. Her initial attack occurred while at a mall with friends. She could not recall an inciting trigger. The attack consisted of sudden loss of tone in the face and bilateral lower extremities. She fell to the floor without alteration of consciousness and sustained abrasions to her knees. Subsequently, she reported occasional precipitation of attacks by emotional shock such as surprise, excitement, or laughter. The events would also rarely be associated with premonitory lightheadedness without visual, olfactory, or sensory auras.

She was born full-term by caesarean section due to failure to progress and had normal birth weight. Her early development was unremarkable. At 2 years of age, she had varicella and also received varicella vaccine in college due inadequate blood titers. Immunizations were complete. There were no drug allergies.

Past medical history included left parietal closed head trauma sustained in a snowboarding accident at age 15 years, resulting in transient 24 hour amnesia and 1 week of decreased concentration without residual deficit. She had 2 clusters of chronic daily headaches of migraine without aura type that began less than a year before the onset of DA, lasted approximately 3 months per cluster and resolved without specific treatment. Her social history was negative for depression, psychosocial problems, or use of tobacco, alcohol, or illicit drugs. Her maternal aunt, paternal grandfather, and female maternal cousin have a history of migraine. A younger brother has attention deficit disorder and Tourette’s syndrome. There is a family history of diabetes, but no history of narcolepsy or cataplexy. General physical and neurological exams were normal.

The initial emergency department evaluation revealed a normal complete blood count, comprehensive metabolic panel, urine pregnancy test, electrocardiogram (ECG), and computerized axial tomography of the head. She was referred to a cardiologist with a presumptive diagnosis of syncope. The cardiologic evaluation included lipid profile, ECG, 24-hour Holter recording, and 2D echocardiogram, which were normal. Neurally mediated syncope was diagnosed and she was advised to liberalize fluid intake, add salt to her diet, and not stand in one place for prolonged periods of time.

Over the next month, she continued to have recurrent DA at a frequency of up to 12 episodes per day. The DAs were stereotypic, characterized by slumping of the torso and head with generalized loss of tone and no alteration of consciousness. Within 10 seconds after the event, she was capable of standing and resuming her activities. She did not report excessive daytime sleepiness, sleep paralysis, or hypnagogic hallucinations. In addition, there was no history for insomnia or parasomnia. A neurology consultation again led to a diagnosis of syncope following normal ECG, magnetic resonance scan with and without contrast, EEG, and lumbar puncture. Six months later, a second cardiologist diagnosed neurally mediated syncope after a normal ECG, 2D echocardiogram, 24-h Holter recording (with captured clinical drop attacks) and tilt table testing. Upon resuming care with her original cardiologist, she underwent extensive ambulatory monitoring of heart rate, heart rhythm, and blood pressure yielding normal results, even during recorded clinical drop attacks. She was then given independent trials of fludrocortisone and midodrine that failed to ameliorate DA. A third cardiology opinion eventuated in a normal EEG, ECG, and tilt table test.

A second neurology consultation led to the clinical diagnosis of isolated cataplexy. Key determinants of the diagnosis included the absence of other narcolepsy tetrad symptoms, preservation of consciousness, lack of pre-syncopal symptoms, and absence of abnormalities on cardiovascular monitoring during recorded drop attacks. The narcolepsy genetic test for and gene mutation was negative. In order to prevent further injury, it was important to initiate treatment urgently to terminate events. She was placed on amitriptyline 25 mg each evening and through serial increases of medication, the attack frequency was reduced from up to 12 episodes per day to complete resolution of the attacks over a 1 year period. However, while on amitriptyline 25–50 mg, she developed a viral gastroenteritis presenting with nausea and vomiting, which precluded taking medication. Over several days of her illness, she had a cluster of brief breakthrough cataplectic attacks that subsided once she was able to tolerate medication. Amitriptyline was increased to 50 mg twice per day.

Further diagnostic studies including human leukocyte antigen (HLA) typing, polysomnography (PSG), multiple sleep latency test (MSLT), and cerebral spinal fluid (CSF) orexin level testing were offered but not performed due to the patient’s refusal and resolution of symptoms from empiric treatment. After having no cataplectic attacks in over 1 year, the medication was tapered and discontinued without recurrence.

3. Discussion

This case illustrates the importance of detailed clinical history and broad differential diagnosis. This patient’s quality of life was dramatically improved by the initiation of medical therapy that targeted cataplexy. She became more confident in her ability to perform activities without collapsing in public. Interestingly, her symptoms recurred during an episode of gastroenteritis with suboptimal medication absorption, and then resolved after the illness. We believe this case likely represents isolated cataplexy, though the lack of HLA typing, PSG, and MSLT in this case are important limitations in the characterization of her disorder.

Cataplectic attacks typically are precipitated by emotions such as anger (90%), excitement (82%), surprise (61%), elation (59%), sexual intercourse (37%), and embarrassment (36%) . Patients may report a brief sensation of lightheadedness during which they are able to brace themselves to prevent serious injury prior to acute muscle weakness. The weakness may affect the entire body or be limited to muscle groups such as jaw, neck, shoulders, or lower extremity muscles. The patient does not lose consciousness during brief (<1 minute) events in which the EEG typically shows normal wakefulness. Events that last >3 minutes may be associated with alteration of consciousness. In longer events (>20 minutes), rapid eye movement (REM) sleep may occur and can be confirmed on the EEG. The prevalence of cataplexy has been reported in up to 29% of young adults with associated excessive daytime sleepiness . The prevalence of isolated cataplexy is unknown. Rare, familial cases of cataplexy with or without associated excessive daytime sleepiness or sleep paralysis have been described and a case of isolated cataplexy of more than 40 years duration has been reported . Some patients have a gradual disappearance of cataplexy with aging, especially in hereditary cases .

The diagnosis of narcolepsy can be confirmed with positive results on polysomnography, MSLT, and HLA typing. Narcolepsy is strongly associated with the HLA alleles and . More than 90% of narcolepsy-cataplexy patients across all ethnic groups carry a specific allele of HLA , while this allele is present in 12%–38% of controls across many ethnic groups . Therefore, while a negative result may be suggestive that the possibility of narcolepsy with associated cataplexy is <10%, a positive result is nonspecific. Neuropeptides (hypocretins/orexins) play an important role in the regulation and maintenance of wakefulness. Approximately 90–95% of patients with narcolepsy-cataplexy have absent CSF levels of hypocretin 1 (orexin A), while CSF hypocretin 1 levels in patients with narcolepsy without cataplexy are usually normal . Findings suggest a loss of hypocretin secreting neurons, possibly due to autoimmune or neurodegenerative process.

Cataplexy may be considered a transition from wakefulness directly to an atonic state as seen in REM sleep, triggered by emotional stimulus. This theory is supported by therapeutic improvement with the use of medications that have REM suppressing action. Medications to treat cataplexy typically have norepinephrine and serotonin reuptake blocking properties (tricyclic antidepressants such as amitriptyline) or stimulate presynaptic release of norepinephrine (amphetamines) . Fluoxetine and venlafaxine have also been utilized. In 2002, sodium oxybate, the sodium salt of γ-hydroxybuterate (GHB) and a metabolite of gamma amino butyric acid (GABA), was approved by the FDA for treatment of cataplexy in patients with narcolepsy. It is thought to reduce cataplectic attacks by binding specifically to GABAB and GHB receptors, although its exact mechanism is unknown.

4. Conclusion

The approach to accurate diagnosis and treatment in a multispecialty setting requires a comprehensive history and broad differential diagnosis. A potential diagnosis of isolated cataplexy should be recognizable by clinical history. Once common conditions have been ruled out, less common conditions must be revisited with a detailed history and physical examination to decrease stress on patients and families undergoing diagnostic testing, provide cost-effective decisions, and treat the condition appropriately. Clinically, our patient exhibited features of isolated cataplexy. Supportive to the diagnosis were the lack of symptoms of the narcolepsy tetrad, lack of alteration of consciousness or pre-syncopal symptoms, and absence of abnormalities on cardiovascular monitoring during recorded drop attacks. Successful resolution of symptoms during empirical treatment with amitriptyline provided the patient with both immediate and long-term improvement in quality of life. Isolated cataplexy is a rare but important consideration in the differential diagnosis of a patient with drop attacks without alteration of consciousness.

Conflict of Interests

The authors declare that they have no conflicts of interests.


The authors are indebted to Alix McNulty, R.N. for her assistance in the preparation of this paper.

The Psychiatric Dimensions of Narcolepsy

Narcolepsy, a disabling disorder that affects approximately 1 of 2000 people worldwide, is characterized by excessive daytime sleepiness (EDS) and frequent overwhelming urges to sleep or inadvertent daytime lapses into sleep. Cataplexy, the sudden, involuntary loss of skeletal muscle tone that lasts from seconds to 1 or 2 minutes, is most often triggered by positive emotions and occurs in up to 70% of cases. Cataplexy can commonly manifest as jaw sagging and/or knees buckling, but it can present more subtly or can result in temporary total-body paralysis, leading to the affected patient falling to the ground. Other characteristic symptoms include sleep paralysis and hallucinations, which classically occur at the transition from wake to sleep, and vice versa (ie, hypnagogic and hypnopompic). In addition, disrupted nighttime sleep is common.

Once they emerge, the symptoms of narcolepsy are usually lifelong, especially when the illness is associated with cataplexy. Although symptoms usually appear in late adolescence or early adulthood, on average there is a delay of 10 years before an accurate diagnosis is established. In part, the delay in diagnosis may stem from a general lack of physician awareness of narcolepsy; the broad array of symptoms that may be difficult to differentiate from symptoms of other disorders; and the wide range of both medical and psychiatric comorbidities associated with narcolepsy, including obesity, other sleep disorders, and psychiatric illnesses. Unfortunately, delay in diagnosing narcolepsy can contribute to the patient’s already significant disease burden, leading to decreased quality of life (QOL).

Diagnosis of narcolepsy

A diagnosis of narcolepsy depends on clinical history and diagnostic testing. Nocturnal polysomnography and the multiple sleep latency test (MSLT) can be used to confirm narcolepsy and evaluate for other causes of EDS. The MSLT quantitates sleep propensity as an objective measure of daytime sleepiness and involves a series of 5 naps separated by 2-hour intervals throughout the day. The diagnostic MSLT findings for narcolepsy include a mean sleep latency (across all 5 naps) of 8 minutes or less with rapid eye movement sleep during at least 2 of the 5 naps.

Accurately diagnosing narcolepsy can be challenging because of a variety of psychiatric comorbidities, including depressive disorders, bipolar disorder, and schizophrenia. The presence of comorbidities may partially mask the symptoms of narcolepsy and result in missed diagnoses. Similarly, narcolepsy without comorbid psychiatric conditions can be mistaken for psychiatric illness, including psychosis. It is important to note that obstructive sleep apnea, often seen in patients with narcolepsy, is also associated with psychiatric disorders.

In addition, there may be symptom overlap between narcolepsy and common psychiatric illnesses; for example, depressed patients may have both EDS and fatigue, and the hypnagogic hallucinations characteristic of narcolepsy may be confused with the hallucinations of psychosis. Furthermore, both patients with narcolepsy and those with psychiatric illnesses may have impaired cognitive performance. Because of the functional impairments characteristic of narcolepsy, including problems at work, at school, and in relationships, and reduced QOL, patients with narcolepsy without comorbid psychiatric disease may be nonetheless referred to a psychiatrist for evaluation.

Given the frequency of missed diagnosis and misdiagnosis of narcolepsy, it is important to have a high index of suspicion and to consider an evaluation for narcolepsy whenever daytime sleepiness is reported or observed. An overnight sleep study and MSLT evaluation should be considered in the diagnostic workup. In the more challenging cases, checking cerebrospinal fluid for hypocretin, which is often decreased or absent in narcolepsy, may help confirm the diagnosis.

An important consideration in the diagnostic evaluation of narcolepsy and other causes of sleepiness is the inclusion of family members or others who know the patient well. Persons close to the patient can often provide essential information that the patient is not fully aware of or is unable to adequatelyarticulate.

Neurological Conditions

Amyotrophic lateral sclerosis (ALS), sometimes called Lou Gehrig’s disease, is a rapidly progressive neurological disease that attacks the nerve cells responsible for controlling voluntary muscles, such as those in the arms, legs, and face.

ALS causes weakness with a wide range of disabilities. Early signs and symptoms include:

  • Difficulty walking or difficulty doing your normal daily activities
  • Weakness in your leg, feet or ankles
  • Tripping
  • Hand weakness or clumsiness
  • Slurring of speech or trouble swallowing
  • Muscle cramps and twitching in your arms, shoulders, and tongue
  • Difficulty holding your head up or keeping a good posture

Eventually, all muscles under voluntary control are affected, and individuals lose their strength and the ability to move their arms, legs, and body. ALS does not affect a person’s ability to see, smell, taste, hear, or recognize touch.


Ataxia is a loss or decrease in the control over fine motor skills. It can be caused by damage to the cerebellum, which is located at the base of the brain and is the region of the brain that controls voluntary motor control. The cerebellum can be damaged by alcohol abuse, stroke, tumors, cerebral palsy, or Multiple Sclerosis.

Symptoms include:

  • Difficulty in buttoning a shirt.
  • An unsteady gait or difficulty walking.
  • Poor coordination in the hands and/or legs.
  • Struggling when performing tasks like handwriting or eating with a fork.
  • Abnormal eye movement or twitching.
  • Increased difficulty in eating/swallowing food.


Epilepsy, a disorder resulting from a disturbance in the electrical conduction of our brains, can result from a number of conditions, causing seizure-like symptoms. Symptoms include:

  • Confusion, usually temporary.
  • Staring off into space.
  • A complete loss of consciousness or memory for a certain period of time.
  • Uncontrolled jerking, tremors, or movement of the arms and legs.
  • Loss of muscle control, resulting in incontinence.

Seizures can result from genetic inheritance, a head trauma, dementia, or medical conditions like heart attack or stroke that affect brain tissue. You should seek medical care the first time you have a seizure. Seek emergency help if the seizure lasts more than five minutes, if you hurt yourself during a seizure, if you are pregnant, or if you are diabetic. Seek medical help if you witness someone having a seizure that meets any of these criteria or if he/she does not begin to breathe or immediately regain consciousness.

Migraine headache

Increased stress, tension, and lack of downtime in today’s hectic world have increased the incidence of migraines in otherwise healthy children and adults. Migraine headaches can take the common headache to extremes, causing severe pain, visual disturbances, nausea, and sensitivity to noise or light.

Migraines can often be controlled through lifestyle changes and/or medication.

Multiple Sclerosis (MS)

The sudden onset on health problems is scary, but early intervention and treatment can make a difference in the severity of associated symptoms. In MS, our central nervous system is damaged by our own immune system, causing symptoms such as:

  • Numbness or tingling in the arms and/or legs, usually on one side of the body at a time, or just in the legs.
  • Visual disturbance, including a ‘blind spot’ or loss of vision in one eye; pain caused by eye movement, double or blurred vision.
  • Tremors or unexplained loss of coordination, including difficulty walking or a feeling of unsteadiness or dizziness.
  • Pain, tingling, or a feeling that something is ‘asleep.’
  • Unexplained fatigue.

Parkinson’s Disease

Parkinson’s disease is a progressive disorder of the nervous system that affects movement. It develops gradually, sometimes starting with a barely noticeable tremor in just one hand. While a tremor may be the most well-known sign of Parkinson’s disease, the disorder also commonly causes stiffness or slowing of movement.

Signs and symptoms include:

  • Tremors
  • Stiff and aching muscles
  • Impaired posture and balance; walking may become difficult
  • Slowed movement, especially when moving from a resting position like getting out of bed
  • Loss of automatic movements, like blinking, smiling, or swinging your arms when walking
  • Weakness of facial and throat muscles

A small number of people have symptoms on only one side of the body that never move to the other side.


An electroencephalogram (EEG) is a test that measures and records brain waves and activity. A number of electrodes, or sensors, are attached to the head and hooked by wires to a computer. The computer records the brain’s electrical activity on the screen or on paper as wavy lines. Certain conditions, such as seizures, can be seen by the changes in the normal pattern of the brain’s electrical activity. It also is used to evaluate people who are experiencing problems associated with brain function. Problems include tumors, confusion, coma, long-term memory difficulties, or weakening of specific parts of the body due to a stroke or other illness.


Electromyography (EMG) measures how fast and how well nerves can send electrical signals throughout the body. It is often performed when patients complain of unexplained muscle weakness. The diagnostic procedure helps distinguish between muscle weakness due to nerve disorders and muscle conditions in which the problem begins in the muscle.

To conduct the test, a small needle is inserted through the skin into the muscle and the patient is asked to move a bit to contract the muscle being tested. Electrical activity is detected by this needle.

EMG is used to detect abnormal electrical activity of muscle that occurs in diseases and conditions including: pinched nerves, amyotrophic lateral sclerosis (ALS), muscular dystrophy, muscle inflammation, peripheral nerve damage (damage to nerves in the arms and legs), myasthenia gravis, disc herniation, and others.


Myelography is a type of radiographic examination that uses a contrast medium to detect issues with the spinal cord, including the location of a spinal cord injury, cysts, and tumors. The procedure often involves injection of a contrast medium into the cervical or lumbar spine, followed by X-rays. A myelogram may help to find the cause of pain not found by an MRI or CT.

Movement Disorders

Ataxia is a degenerative disorder affecting the brain, brainstem or spinal cord. This can result in clumsiness, inaccuracy, instability, imbalance, tremor or a lack of coordination while performing voluntary movements. Movements are not smooth and may appear disjointed or jerky. Patients may fall down frequently due to an unsteady gait. Ataxia also can affect speech and movement of the eyes.

If a metabolic disorder can be identified as the underlying cause, specific treatment may be available in select cases. The cornerstone of treatment for ataxia of parkinsonism (or parkinsonism of any cause) is the use of oral L-DOPA. Other medications used to treat ataxia associated with parkinsonism (or parkinsonism of any cause) include anticholinergics, dopamine agonists, amantadine, selegiline and entacapone. In children with ataxia, generally only anticholinergics are prescribed.

Dystonia is a neurological muscle disorder characterized by involuntary muscle spasms. Dystonia results from abnormal functioning of the basal ganglia, a deep part of the brain which helps control coordination of movement. These regions of the brain control the speed and fluidity of movement and prevent unwanted movements. Patients with dystonia may experience uncontrollable twisting, repetitive movements or abnormal postures and positions. These can affect any part of the body, including the arms, legs, trunk, eyelids and vocal cords. General dystonias involves the entire body. Focal dystonias involve only one body location, most commonly the neck (spasmodic torticollis), eyelids (blepharospasm), lower face (Meige syndrome) or hand (writer’s cramp or limb dystonia). Depending on what part of the body is affected, the condition can be very disabling.

There is a three-tiered approach to treating dystonia: botulinum toxin (botox) injections, medication and surgery. These may be used alone or in combination. Botox injections help block the communication between the nerve and the muscle and may lessen abnormal movements and postures. Surgery is considered when other treatments have proven ineffective. The goal of surgery is to interrupt the pathways responsible for the abnormal movements at various levels of the nervous system. Some operations purposely damage small regions of the thalamus (thalamotomy), globus pallidus (pallidotomy) or other deep centers in the brain. Recently, deep brain stimulation (DBS) has been tried with some success. Other surgeries include cutting nerves leading to the nerve roots deep in the neck close to the spinal cord (anterior cervical rhizotomy) or removing the nerves at the point they enter the contracting muscles (selective peripheral denervation).

Essential Tremor

Essential tremor is an uncontrolled shaking or trembling, usually of one or both hands or arms, that worsens when basic movements are attempted. Essential tremor affects about five million people in the U.S., According to the U.S. National Library of Medicine, essential tremors are found most commonly in adults over the age of 65. It is caused by abnormalities in areas of the brain that control movement and is not tied to an underlying disease (e.g., Parkinson’s disease). About 50 percent of patients have a family history of the condition. This condition usually does not result in serious complications, but it certainly can interfere with daily activities and cause distress.

In some cases, physical therapy or changes in lifestyle may improve symptoms. If the condition affects a patient’s ability to perform daily tasks and has a negative impact on quality of life, medication or surgery are considered. About 50 to 75 percent of patients taking medications have a reduction of their tremor. Beta-blockers, anti-seizure medications, benzodiazepines and carbonic anhydrase inhibitors often are prescribed. Beta-blockers usually are prescribed for younger patients because they may cause memory loss and confusion in older patients. Botox injections help block the communication between the nerve and the muscle and may lessen tremor.

If the tremor is so severe that is causes a disability, surgery may be recommended. Thalamotomy purposely destroys a portion of the area deep within the brain that receives sensory messages, and area known as the thalamus. About 75 percent of patients undergoing this procedure find relief on one side of their body. Surgery on both sides of the thalamus is rarely done due to the high risk of speech loss. Deep Brain Stimulation is another surgical option in severe cases of essential tremor that have not responded to medication. A hair-thin wire is implanted in the thalamus and connected to a neurostimulator implanted under the collarbone. The neurostimulator sends electrical impulses along the wire to the thalamus, interrupting signals that cause tremor.

Huntington’s disease is a progressive, degenerative and fatal disease caused by the deterioration of certain nerve cells in the brain. Onset most often occurs between ages 35 and 50, with the condition progressing without remission over 10 to 25 years. Huntington’s disease affects an estimated one in every 10,000 people in the U.S. A juvenile form of the disease affects patients age 20 and younger, accounting for about 16 percent of all cases. Symptoms include jerking; uncontrollable movements of the limbs, trunk, and face; progressive loss of mental abilities; and the development of psychiatric problems. The condition is hereditary – a child with one affected parent has a 50 percent chance of developing Huntington’s disease.

There is no cure for Huntington’s disease, so treatment focuses on reducing symptoms, preventing complications and helping patients and family members cope with daily challenges. Doctors may prescribe antipsychotics, antidepressants, tranquilizers, mood-stabilizers or botox injections. These are prescribed in the lowest effective dosage, as all of these medications may have side effects. Huntington’s disease usually runs its full terminal course in 10 to 30 years. Researchers have observed that the earlier in life the symptoms occur, the faster the disease often progresses.

MSA is a progressive, neurodegenerative disease affecting movement, blood pressure and other body functions. Because symptoms, onset and severity of MSA vary from person to person, differing ranges of symptoms were designated initially as three different diseases: Shy-Drager syndrome, striatonigral degeneration and olivopontocerebellar atrophy. All of these now are classified under MSA. Symptoms include stiffness or rigidity; freezing or slowed movements; instability; loss of balance; loss of coordination; a significant fall in blood pressure when standing, causing dizziness, lightheadedness, fainting or blurred vision (orthostatic hypotension); male impotence; urinary difficulties; constipation; and speech and swallowing difficulties.

Medication may be prescribed to treat some of the symptoms associated with this disease. Levodopa and dopamine agonists used to treat Parkinson’s disease may be effective in treating slowness and rigidity in some patients. Orthostatic hypotension can be improved by prescribing drugs that raise blood pressure. As MSA progresses, the benefits of medication lessen. In cases that have progressed and are more severe, a feeding tube may be needed when the patient cannot swallow food on his or her own.

Myoclonus is a twitching or intermittent spasm of a muscle or group of muscles. Myoclonus is classified into several major types and many subcategories. The most common type is cortical myoclonus, which arises from an area of the brain known as the sensorimotor cortex. Jerky movements usually have a regular rhythm and may be limited to one muscle or muscle group (focal) or several different muscle groups (multifocal). They may occur without an obvious cause or be a result of many diseases. Some of the diseases associated with myoclonus are Celiac disease, Angelman syndrome, Huntington’s disease, Rett syndrome, Creutzfeldt-Jakob disease and Alzheimer’s disease. Subcortical myoclonus usually affects many muscle groups (generalized) and may be the result of abnormally low levels of oxygen in the brain (hypoxia) or a metabolic process, such as kidney or liver failure. Spinal myoclonus usually is caused by a focal spinal lesion, such as multiple sclerosis, syringomyelia, trauma, ischemic myelopathy or an infection such as herpes zoster, Lyme disease, E. coli or HIV. The jerking often lasts longer and is more variable than in cortical or subcortical myoclonus and continues during sleep. The most common type of peripheral myoclonus is hemifacial spasm, which may occur for no underlying reason or be caused by compression of the facial nerve. Movements persist during sleep and may last for only a few days or for as long as a few months. The exact type of myoclonus is delineated further by the parts of the body affected and by the underlying causes.

Myoclonus is treated through prescribing medications that may help reduce symptoms. In some cases, effective results are achieved by combining multiple drugs. Some of the medications prescribed are barbiturates, phenytoin, primidone, sodium valproate and the tranquilizer clonazepam. All of these medications have potential side effects, so it is very important for patients to work closely with their doctor on medication management.

Parkinson’s disease is a progressive disorder that is caused by degeneration of nerve cells in the part of the brain called the substantia nigra, which controls movement. These nerve cells die or become impaired, losing the ability to produce an important chemical called dopamine. Parkinson’s produces many common symptoms, including tremor; muscle rigidity or stiffness of the limbs; gradual loss of spontaneous movement, often leading to decreased mental skill or reaction time, voice changes or decreased facial expression; gradual loss of automatic movement, often leading to decreased blinking, decreased frequency of swallowing, and drooling; a stooped, flexed posture, with bending at the elbows, knees and hips; an unsteady walk or balance; and depression or dementia. The Parkinson’s Disease Foundation estimates that that 60,000 new cases of Parkinson’s disease are diagnosed each year, adding to the seven to 10 million people who have the disease worldwide. While the risk of a Parkinson’s diagnosis increases with age, four percent of those afflicted are diagnosed before the age of 50.

Most Parkinson’s patients are treated with medications to relieve the symptoms of the disease. Some common medications used are dopamine precursors, dopamine agonists and anticholinergics. Surgery is considered when medications have proven ineffective. Deep Brain Stimulation (DBS) of the subthalamic nucleus or globus pallidus can be effective in treating all of the primary motor features of Parkinson’s and sometimes allows for significant decreases in medication doses. Thalamotomy can help stop tremor by placing a small lesion in a specific nucleus of the thalamus.

Progressive Supranuclear Palsy (PSP)

PSP is a rare brain disorder that causes serious and permanent neurological problems. People with PSP experience a gradual loss of specific brain cells, causing slowing of movement and reduced control of walking, balance, swallowing, speech and eye movement. Often, there are personality and cognitive changes, causing emotional outbursts and a decrease in intellectual abilities. This disease more commonly affects people ages 40 to 60 and usually runs its full terminal course in six to 10 years. It is sometimes misdiagnosed as Parkinson’s disease due to the similarity in symptoms. While the cause of PSP is unknown, researchers know that a brain protein called tau accumulates in abnormal clumps in certain brain cells in people with PSP, causing the cells to die. There appears to be a genetic predisposition.

Unfortunately, there is no effective medication to treat PSP, but research is ongoing. Medications that may have a slight benefit are levodopa, amantadine and amitriptyline. Botox injections may be used to treat the blepharospasm (involuntary eyelid closure) that occurs in some people with PSP.

Rett Syndrome

Rett Syndrome is a progressive neurological disorder that causes debilitating symptoms, including reduced muscle tone, autistic-like behavior, repetitive hand movements, irregular breathing, decreased ability to express feelings, developmental delays in brain and head growth, gait abnormalities and seizures. Loss of muscle tone usually is the first symptom. According to the International Rett Syndrome Foundation, about one in every 10,000 to 23,000 infant girls is diagnosed with Rett, but the prevalence may be much higher due to undiagnosed cases. Rett can affect boys, but they account for a very small percentage of cases. Rett is caused by mutations in the gene MECP2, located on the X chromosome. Children with Rett appear to develop normally until six to 18 months of age, at which point symptoms start to appear. Rett leaves its victims profoundly disabled, requiring maximum assistance with all aspects of daily living.

Unfortunately, there is no cure for Rett. Treatment for the disorder focuses on the management of symptoms and requires a supportive, multidisciplinary approach. The disorder progresses through four major stages, each with characteristic symptoms and medical implications. Medication may be needed for breathing irregularities and motor difficulties. Antiepileptic drugs may be used to control seizures. Occupational therapy, education and supportive services are geared towards helping individuals with Rett cope with daily challenges and maintain a quality of life. Although it is severely debilitating, individuals with Rett have lived to middle age, but rarely beyond ages 40 to 50.

Secondary Parkinsonism is a disorder with symptoms similar to Parkinson’s disease, but caused by medication side effects, different neurodegenerative disorders, illness or brain damage. As in Parkinson’s disease, many common symptoms may develop, including tremor; muscle rigidity or stiffness of the limbs; gradual loss of spontaneous movement, often leading to decreased mental skill or reaction time, voice changes, or decreased facial expression; gradual loss of automatic movement, often leading to decreased blinking, decreased frequency of swallowing, and drooling; a stooped, flexed posture with bending at the elbows, knees and hips; an unsteady walk or balance; and depression or dementia. Unlike Parkinson’s disease, the risk of developing secondary parkinsonism may be minimized by careful medication management, particularly limiting the usage of specific types of antipsychotic medications.

Many of the medications used to treat this condition have potential side effects, so it is very important to work closely with your doctor on medication management. Unfortunately, secondary parkinsonism does not seem to respond as effectively to medical therapy as Parkinson’s disease.

Spasticity is increased muscle contractions causing stiffness or tightness of the muscles that may interfere with movement, speech and walking. Spasticity usually is caused by damage to the portion of the brain or spinal cord that controls voluntary movement. It may result from spinal cord injury, multiple sclerosis, cerebral palsy, stroke, brain damage caused by a lack of oxygen, severe head injury and metabolic diseases such as Lou Gehrig’s disease (ALS).

Treatment may include medications such as baclofen, diazepam, tizanidine and clonazepam. Physical therapy with specific muscle exercises may be prescribed in an effort to help reduce the severity of symptoms. Surgery may be recommended for tendon release or to cut the nerve-muscle pathway. The prognosis depends on the severity of the spasticity and the underlying disorder(s).

TD is a muscle disorder that results from prolonged exposure to some types of antipsychotic and neuroleptic medications. TD is characterized by repetitive, involuntary, purposeless movements such as grimacing, lip smacking, eye blinking or rapid leg and arm movements. The condition can be quite embarrassing because it cannot be controlled. TD may be mild and reversible in many cases. The percentage of patients who develop severe or irreversible TD is quite low in proportion to those receiving long-term antipsychotic therapy. Older adults are more susceptible to persistent and irreversible TD than younger people. New classes of antipsychotic medications have decreased the prevalence of TD considerably.

While there is no treatment for TD, the risk of developing TD may be minimized by prescribing newer classes of antipsychotics to treat psychosis, restricting the long-term use of neuroleptics to well-defined indications and prescribing these medications in the lowest effective dosage. It also is important that patients taking these medications are frequently monitored for symptoms.

Tourette Syndrome

Tourette Syndrome is a hereditary neurological disorder characterized by repeated involuntary movements and uncontrollable vocal sounds called tics. This disorder evidences itself most often between the ages of six and 15, but may occur as early as age two or as late as age 20. The first symptoms often are involuntary movements (tics), most commonly of the face, followed by the arms, legs or trunk. These tics are frequent, repetitive and quick. Verbal tics (vocalizations) usually occur with the movements, but later may replace one or more movement tics. Vocalizations include grunting, throat clearing, shouting and barking. Verbal tics also may be expressed as coprolalia (the involuntary use of obscene words or socially unacceptable words and phrases) or copropraxia (obscene gestures). It is estimated that in 70 percent of cases, the tics disappear in a person’s early 20s.

The major problem faced by people with TS is socialization and acceptance by peers because the condition can be quite embarrassing. Often, tic symptoms do not cause serious enough impairment to require medication. However, there are many types of medications prescribed for those whose symptoms interfere with functioning. Because all of these medications have potentially serious side effects, they should be prescribed in the lowest effective dosage.

Wilson’s Disease is a genetic disorder that causes excessive copper accumulation in the liver or brain. Although copper accumulation begins at birth, symptoms begin appearing between the ages of six and 40, but most commonly in late adolescence. Wilson’s Disease affects an estimated one in 30,000 people worldwide. It is an autosomal recessive disease, occurring equally in males and females. In order to inherit it, both parents must carry a gene that is passed along to the child. Consequences include liver disease and psychiatric and neurological problems. Physical signs include jaundice, abdominal swelling, vomiting of blood, abdominal pain, tremor and difficulty in walking, talking or swallowing. Psychiatric signs include homicidal or suicidal behavior, depression and aggression. If undetected and untreated, the disorder is always fatal.

Early diagnosis is crucial since liver damage may occur before the onset of symptoms. Family members of those with a confirmed diagnosis of Wilson’s Disease require testing and screening for the disease even if they have no symptoms. Screening tests should include the evaluation of serum ceruloplasmin levels and a test for the amount of copper found in the urine over a 24-hour period. Treatment of Wilson’s Disease generally involves removing excess copper from the body and preventing it from reaccumulating. Most cases are treated with the medications zinc acetate, trientine and penicillamine. Penicillamine and trientine increase urinary excretion of copper, but both can cause serious side effects. Zinc acetate blocks the absorption of copper, increases copper excretion in the stool and causes no serious side effects – thus, it often is considered the treatment of choice. Treatment is lifelong and also involves avoiding copper-rich foods in one’s diet.

Additional Information

These websites offer additional helpful information on epilepsy, its causes, treatment options, support and more. (Note: These sites are not under the auspice of AANS, and their listing here should not be seen as an endorsement of these sites or their content.)

  • Bachmann-Strauss Dystonia & Parkinson Foundation
  • Huntington’s Disease Society of America
  • International Rett Syndrome Foundation
  • Michael J. Fox Foundation for Parkinson’s Research
  • National Multiple Sclerosis Society
  • National Parkinson Foundation
  • Parkinson’s Disease Foundation
  • Tardive Dyskinesia
  • Tourette Syndrome Association, Inc

The AANS does not endorse any treatments, procedures, products or physicians referenced in these patient fact sheets. This information is provided as an educational service and is not intended to serve as medical advice. Anyone seeking specific neurosurgical advice or assistance should consult his or her neurosurgeon, or locate one in your area through the AANS’ Find a Board-certified Neurosurgeon online tool.


What is paralysis?

Paralysis is a loss of strength in and control over a muscle or group of muscles in a part of the body. Most of the time, this is not due to a problem with the muscles themselves. It is more likely due to a problem somewhere along the chain of nerve cells that runs from the body part to your brain and back again. These nerve cells deliver the signals for your muscles to move.

There are many types and degrees of paralysis. The condition can be:

  • Partial, when you still have some control of your muscles (sometimes called paresis).
  • Complete, when you can’t move your muscles at all.
  • Permanent, when muscle control never comes back.
  • Temporary, when some or all muscle control returns.
  • Flaccid, when the muscles get flabby and shrink.
  • Spastic, when the muscles are tight and hard and jerk around oddly (spasm).

Paralysis can occur in any part of the body and is either localized, when it affects only one part of the body, or generalized, when it affects a wider area of the body.

Localized paralysis often affects areas such as the face, hands, feet, or vocal cords.

Generalized paralysis is broken down based on how much of the body is paralyzed:

  • Monoplegia affects one limb only, such as one arm or one leg.
  • Hemiplegia affects one side of the body, such as the leg and arm of the same side of the body.
  • Diplegia affects the same area on both sides of the body, such as both arms or both sides of the face.
  • Paraplegia affects both legs and sometimes parts of the trunk.
  • Quadriplegia affects both arms and both legs and sometimes the entire area from the neck down. The function of the heart, lungs, and other organs might also be affected.

How common is paralysis?

A study called the Paralysis Population Survey, which was started by the Christopher and Dana Reeve Foundation and conducted by the University of New Mexico’s Center for Development and Disability, found that nearly 1 in 50 Americans is living with some form of paralysis — about 6 million people.

What causes paralysis?

Muscle movement is controlled by trigger signals relayed from the brain. When any part of the relay system — such as the brain, spinal cord, nerves, or junction between the nerve and the muscle — is damaged, the signals to move do not make it through to the muscles and paralysis results. There are many ways the relay system can be damaged.

A person can be born with paralysis due to a birth defect such as spina bifida, which occurs when the brain, spinal cord, and/or the covering that protects them do not form the right way. In most cases, people get paralysis as the result of an accident or a medical condition that affects the way muscles and nerves function. The most common causes of paralysis include:

  • Stroke
  • Spinal cord injury
  • Head injury
  • Multiple sclerosis

Some other causes include:

  • Cerebral palsy
  • Guillain-Barré syndrome
  • Peripheral neuropathy
  • Toxins/poisons
  • ALS (Lou Gehrig’s disease)

What are the symptoms of paralysis?

Symptoms of paralysis may vary based on the cause, but are often easy to spot. A person born paralyzed due to a birth defect, or paralyzed suddenly due to a stroke or spinal cord injury, will be partially or totally unable to move the affected body parts. At the same time, the person may experience muscle stiffness and decreased feeling in the affected body parts.

A person who becomes paralyzed due to a medical condition might lose muscle control and feeling slowly. The person might feel tingling or numbing sensations or muscle cramps before losing control of his or her muscles.

What other problems can occur with paralysis?

Because paralysis can happen to any muscle or group of muscles, many body functions can be affected. Some of the problems that can occur along with paralysis include:

  • Problems with blood flow, breathing, and heart rate
  • Changes in the normal function of organs, glands, and other tissues
  • Changes to muscles, joints, and bones
  • Skin injuries and pressure sores
  • Blood clots in the legs
  • Loss of urine and bowel control
  • Sexual problems
  • Problems speaking or swallowing
  • Behavior and mood changes

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Muscle function loss

The doctor will perform a physical exam and ask questions about your medical history and symptoms, including:


  • What part(s) of your body are affected?
  • Does it affect one or both sides of your body?
  • Did it develop in a top-to-bottom pattern (descending paralysis), or a bottom-to-top pattern (ascending paralysis)?
  • Do you have difficulty getting out of a chair or climbing stairs?
  • Do you have difficulty lifting your arm above your head?
  • Do you have problems extending or lifting your wrist (wrist drop)?
  • Do you have difficulty gripping (grasping)?


  • Do you have pain?
  • Do you have numbness, tingling, or loss of sensation?
  • Do you have difficulty controlling your bladder or bowels?
  • Do you have shortness of breath?
  • What other symptoms do you have?

Time pattern:

  • Do episodes occur repeatedly (recurrent)?
  • How long do they last?
  • Is the muscle function loss getting worse (progressive)?
  • Is it progressing slowly or quickly?
  • Does it become worse over the course of the day?

Aggravating and relieving factors:

  • What, if anything, makes the paralysis worse?
  • Does it get worse after you take potassium supplements or other medicines?
  • Is it better after you rest?

Tests that may be performed include:

  • Blood studies (such as CBC, white blood cell differential, blood chemistry levels, or muscle enzyme levels)
  • CT scan of the head or spine
  • MRI of the head or spine
  • Lumbar puncture (spinal tap)
  • Muscle or nerve biopsy
  • Myelography
  • Nerve conduction studies and electromyography

Intravenous feeding or feeding tubes may be required in severe cases. Physical therapy, occupational therapy, or speech therapy may be recommended.


Cataplexy is a sudden and uncontrollable muscle weakness or paralysis that comes on during the day and is often triggered by a strong emotion, such as excitement or laughter. Without much warning, the person loses muscle tone and can have a slack jaw, broken speech, buckled knees or total weakness in their face, arms, legs, and trunk. A person experiencing total cataplexy stays awake and is aware of what is happening, but cannot move. These episodes last up to a minute or two, and some people may fall asleep afterwards. The frequency of cataplexy episodes varies widely among people with narcolepsy. Some individuals avoid emotions that may bring on cataplexy.

The loss of muscle tone in cataplexy occurs because of the inability to regulate sleep and awake states — meaning that elements of each can overlap. During normal rapid eye movement (REM) sleep, there is a natural loss of muscle tone. In the case of cataplexy, that characteristic of REM sleep occurs suddenly during the day, causing weakness or full paralysis, even as the person remains awake during the episode.

Narcolepsy Fact Sheet

What is narcolepsy?

Narcolepsy is a chronic neurological disorder that affects the brain’s ability to control sleep-wake cycles. People with narcolepsy usually feel rested after waking, but then feel very sleepy throughout much of the day. Many individuals with narcolepsy also experience uneven and interrupted sleep that can involve waking up frequently during the night.

Narcolepsy can greatly affect daily activities. People may unwillingly fall asleep even if they are in the middle of an activity like driving, eating, or talking. Other symptoms may include sudden muscle weakness while awake that makes a person go limp or unable to move (cataplexy), vivid dream-like images or hallucinations, and total paralysis just before falling asleep or just after waking up (sleep paralysis).

In a normal sleep cycle, a person enters rapid eye movement (REM) sleep after about 60 to 90 minutes. Dreams occur during REM sleep, and the brain keeps muscles limp during this sleep stage, which prevents people from acting out their dreams. People with narcolepsy frequently enter REM sleep rapidly, within 15 minutes of falling asleep. Also, the muscle weakness or dream activity of REM sleep can occur during wakefulness or be absent during sleep. This helps explain some symptoms of narcolepsy.

If left undiagnosed or untreated, narcolepsy can interfere with psychological, social, and cognitive function and development and can inhibit academic, work, and social activities.

Who gets narcolepsy?

Narcolepsy affects both males and females equally. Symptoms often start in childhood, adolescence, or young adulthood (ages 7 to 25), but can occur at any time in life. It is estimated that anywhere from 135,000 to 200,000 people in the United States have narcolepsy. However, since this condition often goes undiagnosed, the number may be higher. Since people with narcolepsy are often misdiagnosed with other conditions, such as psychiatric disorders or emotional problems, it can take years for someone to get the proper diagnosis.

What are the symptoms?

Narcolepsy is a lifelong problem, but it does not usually worsen as the person ages. Symptoms can partially improve over time, but they will never disappear completely. The most typical symptoms are excessive daytime sleepiness, cataplexy, sleep paralysis, and hallucinations. Though all have excessive daytime sleepiness, only 10 to 25 percent of affected individuals will experience all of the other symptoms during the course of their illness.

  • Excessive daytime sleepiness (EDS). All individuals with narcolepsy have EDS, and it is often the most obvious symptom. EDS is characterized by persistent sleepiness, regardless of how much sleep an individual gets at night. However, sleepiness in narcolepsy is more like a “sleep attack”, where an overwhelming sense of sleepiness comes on quickly. In between sleep attacks, individuals have normal levels of alertness, particularly if doing activities that keep their attention.

    • Cataplexy. This sudden loss of muscle tone while a person is awake leads to weakness and a loss of voluntary muscle control. It is often triggered by sudden, strong emotions such as laughter, fear, anger, stress, or excitement. The symptoms of cataplexy may appear weeks or even years after the onset of EDS. Some people may only have one or two attacks in a lifetime, while others may experience many attacks a day. In about 10 percent of cases of narcolepsy, cataplexy is the first symptom to appear and can be misdiagnosed as a seizure disorder. Attacks may be mild and involve only a momentary sense of minor weakness in a limited number of muscles, such as a slight drooping of the eyelids. The most severe attacks result in a total body collapse during which individuals are unable to move, speak, or keep their eyes open. But even during the most severe episodes, people remain fully conscious, a characteristic that distinguishes cataplexy from fainting or seizure disorders. The loss of muscle tone during cataplexy resembles paralysis of muscle activity that naturally occurs during REM sleep. Episodes last a few minutes at most and resolve almost instantly on their own. While scary, the episodes are not dangerous as long as the individual finds a safe place in which to collapse.

  • Sleep paralysis. 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 resembles cataplexy except it occurs at the edges of sleep. As with cataplexy, people remain fully conscious. Even when severe, cataplexy and sleep paralysis do not result in permanent dysfunction—after episodes end, people rapidly recover their full capacity to move and speak.
  • Hallucinations. Very vivid and sometimes frightening images can accompany sleep paralysis and usually occur when people are falling asleep or waking up. Most often the content is primarily visual, but any of the other senses can be involved.

Additional symptoms of narcolepsy include:

  • Fragmented sleep and insomnia. While individuals with narcolepsy are very sleepy during the day, they usually also experience difficulties staying asleep at night. Sleep may be disrupted by insomnia, vivid dreaming, sleep apnea, acting out while dreaming, and periodic leg movements.
  • Automatic behaviors. Individuals with narcolepsy may experience temporary sleep episodes that can be very brief, lasting no more than seconds at a time. A person falls asleep during an activity (e.g., eating, talking) and automatically continues the activity for a few seconds or minutes without conscious awareness of what they are doing. This happens most often while people are engaged in habitual activities such as typing or driving. They cannot recall their actions, and their performance is almost always impaired. Their handwriting may, for example, degenerate into an illegible scrawl, or they may store items in bizarre locations and then forget where they placed them. If an episode occurs while driving, individuals may get lost or have an accident. People tend to awaken from these episodes feeling refreshed, finding that their drowsiness and fatigue has temporarily subsided.

What are the types of narcolepsy?

There are two major types of narcolepsy:

  • Type 1 narcolepsy (previously termed narcolepsy with cataplexy). This diagnosis is based on the individual either having low levels of a brain hormone (hypocretin) or reporting cataplexy and having excessive daytime sleepiness on a special nap test.
  • Type 2 narcolepsy (previously termed narcolepsy without cataplexy). People with this condition experience excessive daytime sleepiness but usually do not have muscle weakness triggered by emotions. They usually also have less severe symptoms and have normal levels of the brain hormone hypocretin.

    A condition known as secondary narcolepsy can result from an injury to the hypothalamus, a region deep in the brain that helps regulate sleep. In addition to experiencing the typical symptoms of narcolepsy, individuals may also have severe neurological problems and sleep for long periods (more than 10 hours) each night.

What causes narcolepsy?

Narcolepsy may have several causes. Nearly all people with narcolepsy who have cataplexy have extremely low levels of the naturally occurring chemical hypocretin, which promotes wakefulness and regulates REM sleep. Hypocretin levels are usually normal in people who have narcolepsy without cataplexy.

Although the cause of narcolepsy is not completely understood, current research suggests that narcolepsy may be the result of a combination of factors working together to cause a lack of hypocretin. These factors include:

  • Autoimmune disorders. When cataplexy is present, the cause is most often the loss of brain cells that produce hypocretin. Although the reason for this cell loss is unknown, it appears to be linked to abnormalities in the immune system. Autoimmune disorders occur when the body’s immune system turns against itself and mistakenly attacks healthy cells or tissue. Researchers believe that in individuals with narcolepsy, the body’s immune system selectively attacks the hypocretin-containing brain cells because of a combination of genetic and environmental factors.
  • Family history. Most cases of narcolepsy are sporadic, meaning the disorder occurs in individuals with no known family history. However, clusters in families sometimes occur—up to 10 percent of individuals diagnosed with narcolepsy with cataplexy report having a close relative with similar symptoms.
  • Brain injuries. Rarely, narcolepsy results from traumatic injury to parts of the brain that regulate wakefulness and REM sleep or from tumors and other diseases in the same regions.

How is narcolepsy diagnosed?

A clinical examination and detailed medical history are essential for diagnosis and treatment of narcolepsy. Individuals may be asked by their doctor to keep a sleep journal noting the times of sleep and symptoms over a one- to two-week period. Although none of the major symptoms are exclusive to narcolepsy, cataplexy is the most specific symptom and occurs in almost no other diseases.

A physical exam can rule out or identify other neurological conditions that may be causing the symptoms. Two specialized tests, which can be performed in a sleep disorders clinic, are required to establish a diagnosis of narcolepsy:

  • Polysomnogram (PSG or sleep study). The PSG is an overnight recording of brain and muscle activity, breathing, and eye movements. A PSG can help reveal whether REM sleep occurs early in the sleep cycle and if an individual’s symptoms result from another condition such as sleep apnea.
  • Multiple sleep latency test (MSLT). The MSLT assesses daytime sleepiness by measuring how quickly a person falls asleep and whether they enter REM sleep. On the day after the PSG, an individual is asked to take five short naps separated by two hours over the course of a day. If an individual falls asleep in less than 8 minutes on average over the five naps, this indicates excessive daytime sleepiness. However, individuals with narcolepsy also have REM sleep start abnormally quickly. If REM sleep happens within 15 minutes at least two times out of the five naps and the sleep study the night before, this is likely an abnormality caused by narcolepsy.

    Occasionally, it may be helpful to measure the level of hypocretin in the fluid that surrounds the brain and spinal cord. To perform this test, a doctor will withdraw a sample of the cerebrospinal fluid using a lumbar puncture (also called a spinal tap) and measure the level of hypocretin-1. In the absence of other serious medical conditions, low hypocretin-1 levels almost certainly indicate type 1 narcolepsy.

What treatments are available?

Although there is no cure for narcolepsy, some of the symptoms can be treated with medicines and lifestyle changes. When cataplexy is present, the loss of hypocretin is believed to be irreversible and lifelong. Excessive daytime sleepiness and cataplexy can be controlled in most individuals with medications.


  • Modafinil. The initial line of treatment is usually a central nervous system stimulant such as modafinil. Modafinil is usually prescribed first because it is less addictive and has fewer side effects than older stimulants. For most people these drugs are generally effective at reducing daytime drowsiness and improving alertness.
  • Amphetamine-like stimulants. In cases where modafinil is not effective, doctors may prescribe amphetamine-like stimulants such as methylphenidate to alleviate EDS. However, these medications must be carefully monitored because they can have such side effects as irritability and nervousness, shakiness, disturbances in heart rhythm, and nighttime sleep disruption. In addition, health care professionals should be careful when prescribing these drugs and people should be careful using them because the potential for abuse is high with any amphetamine.
  • Antidepressants. Two classes of antidepressant drugs have proven effective in controlling cataplexy in many individuals: tricyclics (including imipramine, desipramine, clomipramine, and protriptyline) and selective serotonin and noradrenergic reuptake inhibitors (including venlafaxine, fluoxetine, and atomoxetine). In general, antidepressants produce fewer adverse effects than amphetamines. However, troublesome side effects still occur in some individuals, including impotence, high blood pressure, and heart rhythm irregularities.
  • Sodium oxybate. Sodium oxybate (also known as gamma hydroxybutyrate or GHB) has been approved by the U.S. Food and Drug Administration to treat cataplexy and excessive daytime sleepiness in individuals with narcolepsy. It is a strong sedative that must be taken twice a night. Due to safety concerns associated with the use of this drug, the distribution of sodium oxybate is tightly restricted.

    Lifestyle changes

    Not everyone with narcolepsy can consistently maintain a fully normal state of alertness using currently available medications. Drug therapy should accompany various lifestyle changes. The following strategies may be helpful:

  • Take short naps. Many individuals take short, regularly scheduled naps at times when they tend to feel sleepiest.
  • Maintain a regular sleep schedule. Going to bed and waking up at the same time every day, even on the weekends, can help people sleep better.
  • Avoid caffeine or alcohol before bed. Individuals should avoid alcohol and caffeine for several hours before bedtime.
  • Avoid smoking, especially at night.
  • Exercise daily. Exercising for at least 20 minutes per day at least 4 or 5 hours before bedtime also improves sleep quality and can help people with narcolepsy avoid gaining excess weight.
  • Avoid large, heavy meals right before bedtime. Eating very close to bedtime can make it harder to sleep.
  • Relax before bed. Relaxing activities such as a warm bath before bedtime can help promote sleepiness. Also make sure the sleep space is cool and comfortable.
  • Safety precautions, particularly when driving, are important for everyone with narcolepsy. People with untreated symptoms are more likely to be involved in automobile accidents although the risk is lower among individuals who are taking appropriate medication. EDS and cataplexy can lead to serious injury or death if left uncontrolled. Suddenly falling asleep or losing muscle control can transform actions that are ordinarily safe, such as walking down a long flight of stairs, into hazards.
  • The Americans with Disabilities Act requires employers to provide reasonable accommodations for all employees with disabilities. Adults with narcolepsy can often negotiate with employers to modify their work schedules so they can take naps when necessary and perform their most demanding tasks when they are most alert. Similarly, children and adolescents with narcolepsy may be able to work with school administrators to accommodate special needs, like taking medications during the school day, modifying class schedules to fit in a nap, and other strategies.

    Additionally, support groups can be extremely beneficial for people with narcolepsy who want to develop better coping strategies or feel socially isolated due to embarrassment about their symptoms. Support groups also provide individuals with a network of social contacts who can offer practical help and emotional support.

What is the state of the science involving narcolepsy?

In the past few decades, scientists have made considerable progress in understanding narcolepsy and identifying genes strongly associated with the disorder.

Groups of neurons in several parts of the brain interact to control 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 primary cause of type 1 narcolepsy. These neurons are important for stabilizing sleep and wake states. When these neurons are gone, changes between wake, REM sleep, and non-REM sleep can happen spontaneously. This results in the sleep fragmentation and daytime symptoms that people with narcolepsy experience.

It remains unclear exactly why hypocretin neurons die. However, research increasingly points to immune system abnormalities. HLA—human leukocyte antigen—genes play an important role in regulating the immune system. This gene family provides instructions for making a group of related proteins called the HLA complex, which helps the immune system distinguish between good proteins from an individual’s own body and bad ones made by foreign invaders like viruses and bacteria. One of the genes in this family is HLA-DQB1. A variation in this gene, called HLA-DQB1*06:02, increases the chance of developing narcolepsy, particularly the type of narcolepsy with cataplexy and a loss of hypocretins (also known as orexins). HLA-DQB1*06:02 and other HLA gene variations may increase susceptibility to an immune attack on hypocretin neurons, causing these cells to die. Most people with narcolepsy have this gene variation and may also have specific versions of closely related HLA genes.

However, it is important to note that these gene variations are common in the general population and only a small portion of the people with the HLA-DQB1*06:02 variation will develop narcolepsy. This indicates that other genetic and environmental factors are important in determining if an individual will develop the disorder.

Narcolepsy follows a seasonal pattern and is more likely to develop in the spring and early summer after the winter season, a time when people are more likely to get sick. By studying people soon after they develop the disorder, scientists have discovered that individuals with narcolepsy have high levels of anti-streptolysin O antibodies, indicating an immune response to a recent bacterial infection such as strep throat. Also, the H1N1 influenza epidemic in 2009 resulted in a large increase in the number of new cases of narcolepsy. Together, this suggests that individuals with the HLA-DQB1*06:02 variation are at risk for developing narcolepsy after they are exposed to a specific trigger, like certain infections that trick the immune system to attack the body.

What research is being done?

The mission of the National Institute of Neurological Disorders and Stroke (NINDS) is to seek fundamental knowledge about the brain and nervous system and to use that knowledge to reduce the burden of neurological disease. The NINDS is a component of the National Institutes of Health (NIH), the leading supporter of biomedical research in the world.

The NINDS, along with several other NIH Institutes and Centers, supports research on narcolepsy and other sleep disorders through grants to medical institutions across the country. Additionally, the NIH’s National Heart, Lung, and Blood Institute manages the National Center on Sleep Disorders Research (NCSDR), which coordinates Federal government sleep research activities, promotes doctoral and postdoctoral training programs, and educates the public and health care professionals about sleep disorders. For more information, visit the NCSDR website at

Genetics and biochemicals
NINDS-sponsored researchers are conducting studies devoted to further clarifying the wide range of genetic —both HLA genes and non-HLA genes—and environmental factors that may cause narcolepsy. Other investigators are using animal models to better understand hypocretin and other chemicals such as glutamate that may play a key role in regulating sleep and wakefulness. Researchers are also investigating wake-promoting compounds to widen the range of available therapeutic options and create treatment options that reduce undesired side effects and decrease the potential for abuse. A greater understanding of the complex genetic and biochemical bases of narcolepsy will eventually lead to new therapies to control symptoms and may lead to a cure.

Immune system
Abnormalities in the immune system may play an important role in the development of narcolepsy. NINDS-sponsored scientists have demonstrated the presence of unusual immune system activity in people with narcolepsy. Further, strep throat and certain varieties of influenza are now thought to be triggers in some at-risk individuals. Other NINDS researchers are also working to understand why the immune system destroys hypocretin neurons in narcolepsy in the hopes of finding a way to prevent or cure the disorder.

Sleep biology
The NINDS continues to support investigations into the basic biology of sleep, such as examining the brain mechanisms involved in generating and regulating REM sleep and other sleep behaviors. Since sleep and circadian rhythms are controlled by networks of neurons in the brain, NINDS researchers are also examining how neuronal circuits function in the body and contribute to sleep disorders like narcolepsy. A more comprehensive understanding of the complex biology of sleep will give scientists a better understanding of the processes that underlie narcolepsy and other sleep disorders.

How can I help research?

The NINDS supports the NIH NeuroBioBank, a national resource for investigators using human post-mortem brain tissue and related biospecimens for their research to understand conditions of the nervous system. The NeuroBioBank serves as a central point of access to collections that span neurological, neuropsychiatric, and neurodevelopmental diseases and disorders. Tissue from individuals with narcolepsy is needed to enable scientists to study this disorder more intensely. Participating groups include brain and tissue repositories, researchers, NIH program staff, information technology experts, disease advocacy groups, and, most importantly, individuals seeking information about opportunities to donate. More information about NeuroBioBank and opportunities to donate tissue is available at

Additionally, the NINDS supports genetic and immunological research in narcolepsy at Stanford University. Blood samples from individuals with narcolepsy can be sent by mail and are needed to enable scientists to study this disorder more intensely. Prospective donors may contact:

Stanford University Center for Narcolepsy
450 Broadway Street
M/C 5704
Redwood City, CA 94063

Where can I get more information?

For more information on neurological disorders or research programs funded by the National Institute of Neurological Disorders and Stroke, contact the Institute’s Brain Resources and Information Network (BRAIN) at:


P.O. Box 5801

Bethesda, MD 20824

Information is also available from the following organizations:

Narcolepsy Network
46 Union Drive #A212
North Kingstown, RI 02852

National Sleep Foundation
1010 N. Glebe Road, Suite 420
Arlington, VA 22201

Wake Up Narcolepsy
P.O. Box 60293
Worcester, MA 01606

U.S. National Library of Medicine
National Institutes of Health/DHHS
8600 Rockville Pike
Bethesda, MD 20894

“Narcolepsy Fact Sheet”, NINDS

NIH Publication No. 17-1637

Back to Narcolepsy Information Page

See a list of all NINDS disorders

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Prepared by:
Office of Communications and Public Liaison
National Institute of Neurological Disorders and Stroke
National Institutes of Health
Bethesda, MD 20892

NINDS health-related material is provided for information purposes only and does not necessarily represent endorsement by or an official position of the National Institute of Neurological Disorders and Stroke or any other Federal agency. Advice on the treatment or care of an individual patient should be obtained through consultation with a physician who has examined that patient or is familiar with that patient’s medical history.

All NINDS-prepared information is in the public domain and may be freely copied. Credit to the NINDS or the NIH is appreciated.

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