Narcolepsy, characterized by extreme sleepiness during the day, can have serious negative effects on the health of children, teenagers, and adults.
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Type 1 narcolepsy (NT1) and type 2 narcolepsy (NT2) are extremely uncommon. As a pair, they probably harm less than 100 persons per 100,000.
Due to the rarity of narcolepsy, many instances are presumed to go misdiagnosed or to be diagnosed well after the onset of symptoms. A patient’s safety and quality of life may be jeopardized if they do not receive treatment in a timely manner following a delayed diagnosis.
The diagnosis of narcolepsy is a multi-step process that often involves a number of medical testing and sleep studies. Knowing what to expect from their doctor during appointments and testing might help people with narcolepsy deal through their symptoms.
What is narcolepsy?
Chronic narcolepsy is a neurological condition that disrupts the brain’s natural sleep-wake cycles. Those who suffer from narcolepsy often feel refreshed upon rising, but subsequently sleep excessively for the better part of the day. Many people with narcolepsy also report having trouble falling or staying asleep, or waking up repeatedly during the night.
Everyday life can be severely impacted by narcolepsy. A person can be in the middle of doing something, like driving, eating, or conversing, and suddenly find themselves dozing off. Cataplexy, a sudden weakness of the muscles that renders the person immobile, is another symptom, as are hallucinations and dreamlike imagery, as well as complete paralysis right before sleep or right after awakening (sleep paralysis).
After 60–90 minutes of a regular sleep cycle, a person enters rapid eye movement (REM) sleep.
Dreaming happens during rapid eye movement (REM) sleep, however because the brain relaxes the muscles during this period of sleep, people don’t act out their dreams.
With narcolepsy, REM sleep can occur as early as 15 minutes after falling asleep.
It is also possible for REM sleep characteristics such as muscle weakness or dream activity to happen while awake.
Some of the signs and symptoms of narcolepsy may now be clearer.
If narcolepsy isn’t properly identified and treated, it can have serious consequences for a person’s mental health, preventing them from achieving their full potential at school, at work, and in their personal relationships.
Who Diagnoses Narcolepsy?
Medical doctors are the only ones qualified to diagnose narcolepsy. A medical professional, typically your PCP, will organize the diagnostic process.
Additional assessments by a sleep specialist, neurologist, and/or psychiatrist may be recommended in some circumstances to help with diagnosis and therapy.
What are the symptoms?
Although narcolepsy affects people for the rest of their lives, it often does not get worse with age. Even if symptoms do improve slightly over time, they will never fully disappear. Daytime sleepiness, cataplexy, sleep paralysis, and hallucinations are the most common signs. Ten percent to twenty-five percent of those who contract the disease will experience all of the other symptoms during the course of their illness, though every single one of them will have extreme daytime sleepiness.
- Excessive drowsiness during the day (EDS). EDS is present in everyone who has narcolepsy and is frequently the most noticeable symptom. With EDS, daytime sleepiness is always a problem, even if you get enough of shut-eye at night. In contrast, the tiredness associated with narcolepsy is more akin to what is known as a “sleep attack,” in which a sudden and severe feeling of sleepiness strikes. A person’s regular degree of attentiveness returns in the time between sleep attacks, especially if they’re occupied with something interesting.
- Cataplexy. Weakness and a lack of control over one’s muscles result from this rapid loss of muscular tone while awake. Experiencing quick and intense joy, anxiety, wrath, tension, or excitement might set it off. Cataplexy symptoms may not present themselves until long after the onset of EDS. Attack frequency can vary greatly from person to person, from as few as one or two per lifetime to as many as several every day. Cataplexy is the presenting symptom of narcolepsy in roughly 10% of individuals and might be mistaken for a seizure disorder in those circumstances. An individual may experience a modest attack, which manifests as a temporary feeling of weakness in a small group of muscles (such as a drooping of the eyelids). In the worst cases, victims experience a complete collapse of their body, rendering them unable to breathe, speak, or even keep their eyes open. Cataplexy differs from fainting and seizure disorders in that even during the most severe bouts, people are still completely cognizant. Cataplexy causes a reduction of muscular tone that is similar to the paralysis of muscle action that happens during rapid eye movement (REM) sleep. Episodes typically last no more than a few minutes and go away on their own. While frightening, these episodes pose minimal danger so long as the victim can locate a safe spot to collapse.
- Asleep paralysis. Similar to REM-induced inhibitions of voluntary muscular action, the incapacity to move or talk during sleep or awakening often only lasts for a few seconds or minutes. Similar to cataplexy, but occurring on the cusp of sleep, is sleep paralysis. Just like with cataplexy, sufferers of this condition maintain full consciousness throughout. Cataplexy and sleep paralysis, even when severe, do not cause long-term impairment; after episodes finish, people quickly regain full movement and speech capabilities.
- Hallucinations. Sleep paralysis often occurs at bedtime or upon waking, and is accompanied by vivid, often terrifying, imagery. While visuals are usually the focus, any of the senses can be utilized.
There are other signs of narcolepsy, such as:
- The inability to sleep or only sleeping in small increments. Narcoleptics often have trouble falling asleep at night, in addition to their daytime sleepiness. Insomnia, vivid dreams, sleep apnea, inappropriate behavior in dreams, and restless leg syndrome are all potential sleep disruptors.
- Habitual ways of acting. The sleep episodes experienced by people with narcolepsy are often quite brief, lasting only a few seconds at a time. When a person nods off while doing something (eating, conversing), they may unknowingly carry on with their task for several seconds or minutes. This is particularly common during routine activities like typing or driving. Because of this, they are unable to reflect on their behavior and typically exhibit diminished competence. For example, their handwriting may deteriorate into an unreadable scrawl, or they may begin to store goods in inexplicable places and afterwards forget where they put them. Individuals’ safety on the road could be jeopardized if an incident occurred while they were driving. It’s common for people to wake up from these periods feeling revitalized, with their lethargy and drowsiness having vanished.
What are the types of narcolepsy?
The two most common forms of narcolepsy are:
- Narcolepsy, Type 1. (previously termed narcolepsy with cataplexy). Cataplexy and excessive daytime sleepiness on a particular nap test or low levels of a brain hormone (hypocretin) are the basis for this diagnosis.
- Narcolepsy, Type 2 (previously termed narcolepsy without cataplexy). People with this illness have extreme daytime sleepiness but normally do not have muscle weakness prompted by emotions. They usually also experience less severe symptoms and have normal levels of the brain hormone hypocretin. If the hypothalamus, a small area deep in the brain that controls sleep, is damaged, the person may develop secondary narcolepsy. Individuals with narcolepsy may not only have difficulty staying awake during the day (among other symptoms), but also have serious neurological issues and sleep for long stretches at night (often more than 10 hours).
What causes narcolepsy?
Multiple factors could contribute to narcolepsy’s development. Hypocretin, a naturally occurring hormone that encourages wakefulness and controls rapid eye movement (REM) sleep, is absent or present in extremely low amounts in nearly all patients with narcolepsy who experience cataplexy. Most patients with narcolepsy who do not also suffer from cataplexy have normal levels of hypocretin.
Current research reveals that a lack of hypocretin may be the result of a mix of circumstances, although the exact origin of narcolepsy remains unknown. This is due to a combination of variables, including:
- Condition characterized by abnormal immunological response. The loss of hypocretin-producing brain cells is the most common underlying cause of cataplexy. Although the exact cause of this cell death is yet unknown, it seems to be connected to immune system dysfunction. In the case of autoimmune illnesses, the immune system falsely targets healthy cells and tissue. Some people’s immune systems may be predisposed to target hypocretin-containing brain cells, leading researchers to suspect that a combination of hereditary and environmental factors may cause narcolepsy.
- Origin stories. Almost of cases of narcolepsy are sporadic, meaning there is no familial history of the condition. Up to 10% of people with a diagnosis of narcolepsy with cataplexy say they have a close family who also has the disorder.
- Injury to the brain. Traumatic brain damage, tumors, and other disorders affecting the regions of the brain responsible for regulating alertness and rapid eye movement (REM) sleep are rare causes of narcolepsy.
How Is Narcolepsy Diagnosed?
Concerned individuals should first consult their primary care physician or family doctor regarding excessive daytime sleepiness (EDS) or narcolepsy. The diagnostic procedure, which often consists of numerous stages, might begin with this initial point of contact.
Initial medical care will likely consist of the doctor asking you questions about your symptoms, looking through your medical records, and conducting a brief physical exam.
Your doctor may inquire as follows to better understand your symptoms:
- Typically, how many hours do you sleep each night?
- Are you having trouble getting to sleep?
- How frequently do you find yourself awakening in the middle of the night?
- Do you find yourself drowsy during the day and/or needing to nap?
- How frequently in the past two weeks have you unexpectedly dozed off?
- Do you find yourself nodding off without warning at work?
- How can daily sleepiness effect your performance in the classroom, on the job, or behind the wheel?
- When you first open your eyes in the morning, how do you feel? When you get out of bed after a nap?
- When you nap, do you dream?
- Is weekend sleep longer than weekday sleep for you?
- Do you ever feel like you can’t move or have hallucinations right before you fall asleep or wake up?
- Have you ever suffered from cataplexy, a sudden and short loss of muscular tone or control?
- In your sleep, do you snore loudly or produce gasping or choking noises?
Many different things can trigger EDS, so your answers below will help the doctor zero in on the most likely culprit. Another way to narrow down the potential reasons of your symptoms is to get a full medical history and check your current medications.
The Epworth Sleep Scale is a brief test your doctor may have you take to learn more about your sleeping habits (ESS). The doctor can use your impressions of how sleepy you feel from these survey questions.
Keeping a sleep record, or diary of your sleep patterns, for a week or longer may also be required. Actigraphy is a form of sleep monitoring that makes use of a wearable tracker similar to a watch.
Despite the importance of these details, a diagnosis of narcolepsy cannot be made based on them alone. Instead, more testing is required to rule out alternative explanations for symptoms and confirm a diagnosis of narcolepsy.
Polysomnography and the Multiple Sleep Latency Test
It is normal practice for doctors to offer two different types of sleep testing if they suspect a patient has narcolepsy or another sleep problem.
- Overnight in a sleep clinic, you’ll undergo a procedure called polysomnography (PSG), which records your vital signs and monitors your eye and muscle movement and brain activity. Sleep apnea and other sleep disorders can be diagnosed using PSG since it records your sleep patterns and awakenings.
- In most cases, the Multiple Sleep Latency Test (MSLT) comes right after the polysomnogram (PSG) is finished in the morning. You will keep your PSG sensors attached throughout the duration of the exam. You will be asked to try to sleep at five different periods, and the MSLT will record how quickly you drift off and reach REM sleep at each of those times.
The Polysomnogram (PSG) and the Multiple Sleep Latency Test (MSLT) are both elaborate procedures that must be carried out in a devoted sleep center. Because of the need for constant monitoring of brain activity, home testing for narcolepsy is not feasible.
The PSG and MSLT findings may prove decisive in making a narcolepsy diagnosis. The average time it takes someone with narcolepsy type 1 (NT1) or type 2 (NT2) to fall asleep is less than eight minutes, and they enter REM sleep far earlier than the general population.
Proper preparation is essential to achieving reliable outcomes on these examinations. You should get ready by keeping a sleep journal or an actigraph to record your sleep patterns for at least a week before the test. Avoiding sleep-disrupting drugs or chemicals is also recommended.
Before you go in for one of these sleep studies, your doctor or a technician at the sleep clinic can give you detailed instructions and explain what to expect.
Hypocretin and HLA Testing
Cerebrospinal fluid (CSF) is drawn from the lower spine during a lumbar puncture, and the resulting sample can be analyzed for hypocretin concentration. Hypocretin, also known as orexin, is a molecule that has a role in modulating sleep and wakefulness. In those with narcolepsy type 1, when hypocretin-producing neurons die out, low levels of the hormone are a telltale sign of the disorder.
Almost everyone with NT1 also carries a mutation in a gene called HLA-DQB1*06:02, which is associated with reduced hypocretin levels. While this polymorphism can be looked for with human leukocyte antigen (HLA) testing, it cannot be used to diagnose narcolepsy on its own because it is present in many persons who do not have the disorder.
Other Medical Tests
If your doctor suspects and wants to rule out another ailment as the source of your symptoms, they may order further, non-routine tests, such as blood work or imaging.
What Are the Criteria for Diagnosing Narcolepsy?
Your doctor will be able to tell if you have narcolepsy based on your symptoms, the findings of the physical examination, and the outcomes of any sleep studies or other testing that have been performed.
There are various diagnostic criteria for narcolepsy types 1 and 2. Cataplexy, the rapid and transient loss of muscular tone associated with happy emotions, is a key differentiator between the two illnesses. Cataplexy is an NT1 disorder.
The following table provides a comparison of the diagnostic criteria:
Narcolepsy Type 1
The individual must satisfy both of the following conditions:
- ED that lasts more than three months
- One of at least:
- PSG/MSLT findings of rapid eye movement (REM) sleep phase (Sleep) awakening and symptom onset in cataplexy
- Insufficient hypocretin in the cerebrospinal fluid.
Narcolepsy Type 2
All of the following five conditions must be present in the patient:
- Exertion-induced dystonia that lasts for more than three months.
- Fast sleep onset and rapid eye movement (REM) sleep phase onset times as measured by
- Polysomnography/hypnosis overnight (PSG/MSLT).
- No signs of cataplexy.
- In the cerebrospinal fluid, hypocretin levels are either normal or are not known.
- There is no other illness that can account for the symptoms and lab work.
A person’s diagnosis may shift when more information becomes available. Ten percent or so of those given an NT2 diagnosis later suffer cataplexy, at which point their condition is reclassified as NT1.
What Disorders Can Mimic Narcolepsy?
Other illnesses may have symptoms with narcolepsy, making a diagnosis more challenging.
About a third of Americans don’t get enough sleep, which can lead to drowsiness during the day. Insomnia, sleep apnea, and other sleep disorders, as well as a wide range of neurological and mental health issues, can all contribute to EDS.
Although cataplexy is NT1-specific, it might be misunderstood for other neurological disorders including seizures or strokes. Sleep paralysis and hallucinations, for example, are not exclusive to narcolepsy but can arise as secondary manifestations of other diseases.
In contrast to NT1, which can be diagnosed with a cerebrospinal fluid hypocretin level test, NT2 has no such reliable diagnostic sign. Because its symptoms are similar to those of other illnesses, such as idiopathic hypersomnia and insufficient sleep syndrome, doctors often have to exercise discretion when making a diagnosis.
Is Narcolepsy Diagnosed the Same Way in Children, Teens, and Adults?
A narcolepsy diagnosis is made using the same procedure and criteria regardless of age. However, additional factors may be taken into account when assessing pediatric patients:
- It is possible for narcolepsy to be mistaken as attention-deficit/hyperactivity disorder (ADHD) or another behavior problem in children with EDS because these symptoms often accompany EDS.
- A child’s first symptoms of cataplexy may be more modest than an adult’s, and may entail facial motions. These could easily be misunderstood or dismissed as innocuous facial tics.
- For younger children, who may have trouble recalling their sleep habits or verbalizing symptoms like sleep paralysis or hallucinations, parental involvement during the diagnosis procedure is typically necessary.
- Some adolescents with narcolepsy may initially test normal on the MLST because the test has not been properly validated for this age group.
What Questions Can You Ask Your Doctor About Narcolepsy?
Being prepared for a doctor’s appointment about narcolepsy is a good idea. Make sure you’re ready to give a detailed account of your symptoms and how long you’ve been experiencing them. It could be helpful if you came prepared with a list of questions to ask. Possible questions could be along the lines of:
- What I want to know is if my signs and symptoms indicate narcolepsy.
- Is there any other possible explanation for my condition?
- How would you go about diagnosing what is causing my symptoms?
- Do you have any tips for how I might best prepare for the exams you suggest?
- When can we expect to see the outcomes of these examinations?
- What, if anything, can I do in the interim to alleviate my symptoms?
- Is it time to schedule a visit with a sleep doctor or other medical professional?