There are wide variations between both the development and the
severity of the symptoms of narcolepsy as experienced by different
individuals. The symptoms usually appear independent of one
another (sometimes years apart). In addition, the sequence in which
symptoms appear is not uniform. Typically, the symptoms are rather
mild at the start and increase in severity at a gradual rate over a
period of years. Sometimes no change in severity can be perceived
for months or years and at other times a change occurs very
Excessive Daytime Sleepiness (EDS) and Cataplexy are the two primary symptoms of narcolepsy. Either can become so severe as to completely disable the sufferer. Other symptoms include Disrupted Nighttime Sleep, Sleep Paralysis, Hypnagogic Hallucinations, and Automatic Behavior . However, only 20 to 25 percent of narcolepsy patients suffer the complete range of symptoms.
EDS is usually the first symptom to be noted. It is sometimes expressed as sleepiness, tiredness, lack of energy, sleep attacks, irresistible sleepiness or sleep or an unusual susceptibility to becoming sleepy or falling asleep. In general, the development of EDS is a slow process sometimes requiring several years to become an obvious problem. Although this pathological sleepiness is present every day, the intensity varies throughout each day and the afflicted individual may only be troubled by or even aware of the more severe of the daily episodes. It is impossible for an individual suffering from narcolepsy to resist feeling sleepy or falling asleep. Unfortunately, a person with narcolepsy has this problem no matter how much sleep they get each night. EDS becomes most obvious when, as is often the case, the person becomes sleepy or falls asleep at inappropriate times. Sometimes these sleep "attacks" occur with little or no warning and the person falls asleep without realizing that they are about to do so. At other times, an approaching attack can be detected, resisted, and the sleep can be put off for a few minutes or even a few hours. Some patients always have an advance warning, some have an occasional warning, and others never have a warning. Wide variations in this aspect are common. If an attack is successfully resisted, the person is likely to remain very sleepy or susceptible to falling asleep very easily.
There appears to be a wide range of sleepiness involved in narcolepsy, extending from those who feel alert and completely awake most of the time with occasional daily brief episodes of sleepiness or sleep to those who feel that they are always tired and fighting off sleep. Some patients report that their sleep attacks never fully relieve their feelings of sleepiness, tiredness, lack of energy or fatigue.
Cataplexy is an abrupt loss of voluntary muscle control usually triggered by emotions such as those associated with laughter, anger, or surprise. Episodes of cataplexy occur in approximately 60 percent of patients with narcolepsy. Attacks can also be brought on by a feeling of elation while watching a movie or reading a book. In some patients, cataplexy can be caused by merely remembering a happy or funny event or by thinking about an emotionally charged situation. A catapletic "attack" can range from a brief experience of partial muscle weakness to an almost complete loss of muscle control lasting for several minutes and resulting in a total physical collapse during which the victim is unable to move or speak, although still conscious and at least partially aware of activities going on around them. During an attack, a person may experience blurred vision and have difficulty speaking. A sagging jaw and tilted head are common during an attack and are frequently accompanied by a slight buckling of the knees. Sometimes an attack will appear as a convulsion-like, jerking motion, as muscles rapidly go from being limp to being partially under control, and back to being limp again.
When cataplexy first appears, the attacks are typically mild and infrequent. In addition, the frequency of the attacks and the severity of individual attacks varies tremendously from attack to attack and from person to person. Some patients have only one or two attacks a year while others may have literally hundreds of attacks each day. The attacks typically last from a few seconds to as long as 30 minutes. In addition, a cataplectic attack in a person who is sitting or reclining may gradually develop into a sleep attack.
Disrupted Nighttime (or Nocturnal) Sleep refers to multiple awakenings which occur during each sleep period. The cause may be frightening dreams, the need to relieve one's bladder, or temporary suspensions of breathing, also known as Sleep Apnea. Awakenings sometimes occur with no known cause. Often awakenings are accompanied by a craving for something to eat.
Sleep Paralysis refers to an awareness of one's inability to move despite the desire to do so. It occurs as a person is just falling asleep or just waking up from sleep. Inability to speak usually occurs as part of the paralysis, and occasionally there are hallucinations which accompany the paralysis. If occurring in conjunction with a frightening hypnagogic hallucination, it can add to the terror of the experience.
Hypnagogic Hallucinations are intense vivid experiences which occur at the beginning or end of a sleep period. Any or all of the normal senses may be involved and the experience is frequently extremely difficult to distinguish from reality. Often the person has the sensation of being paralyzed and then becomes aware of some threatening figure or event nearby. Typically hypnagogic hallucinations usually involve the bedroom or areas near to where the person is sleeping and where the person believes they detect and invader who is about to harm them. Less frequently, the hallucinations involve some environment other than the sleep situation.
Automatic Behavior refers to doing things with greatly reduced awareness of, and intelligent control over, the activities involved. Generally one is unable to recall the specific details of the activity once it has been completed and the person usually regards the period of time involved as a "blackout". Some incidents that have been reported include driving home after work and "waking up" in the wrong section of town, parked on a wrong street, or in a neighbor's driveway. Other reports include writing meaningless sentences, or interjecting unrelated subjects into a conversation.
Sleep Apnea is not considered a symptom of narcolepsy; however, it is experienced more frequently by those who are also afflicted with narcolepsy than by other members of the general population. Sleep Apnea involves frequent cessation of breathing which occur during each sleep period.
Narcolepsy has a characteristic age when symptoms first appear, usually in the 10 years between age 10 and age 20. Approximately five percent of the cases begin before the age of 10, 25 percent after the age of 20, and 18 percent after the age of 30. It is very uncommon for narcolepsy to begin after the age of 40. Usually sleep attacks and daytime sleepiness are the first symptoms to appear, followed in a few years by the appearance of cataplexy. However, in some cases, sleepiness, sleep attacks, and cataplexy develop at the same time. While still in other cases, cataplexy is the fist symptom to appear.
It is suspected that narcolepsy (or a predisposition to develop narcolepsy) may be an inheritable characteristic which can be passed from an afflicted parent to his or her children. Several studies have shown that narcolepsy is concentrated in families. Relatives of those with narcolepsy seem to have as much as a 200-fold greater risk of developing narcolepsy than individuals in the general population. This does not indicate that the children of a narcoleptic parent are sure to develop narcolepsy. It indicates only that children of a narcoleptic parent tend to develop narcolepsy more often than do members of the normal population. Offsprings of narcoleptics have about a one in 20 chance of being afflicted with narcolepsy, a rate that is 200 times more likely than the general public. As many as 74.6 percent of first-degree relatives of narcoleptics also have narcolepsy or some other sleeping disorder. If a parent has the condition, children should be observed closely and should be evaluated for narcolepsy if symptoms are noticed. Young patients with only one or two symptoms will often find that these symptoms worsen with age, and more symptoms may appear as they grow older.
It was once believed by some that narcolepsy was a psychological problem with a psychological cause; however, considerable research has demonstrated that this is not true and narcolepsy is now considered a neurologic disease with an impaired brain regulatory sleep/waking mechanism being the primary cause.
The educational and social life of a person with narcolepsy can be extraordinarily disrupted. There is a great impairment of the ability to read, study, and learn. Parents, teachers, physicians, or spouses are frequently confused about the cause of the symptoms and people frequently and incorrectly attribute motivational concerns and pure laziness to the sleepiness associated with the disorder.
A definite diagnosis of narcolepsy may be made by means of a clinical sleep laboratory test. To remove any doubt that a person does or does not have narcolepsy this laboratory test should be conducted, unless the person has an absolutely clear cut history of cataplexy. If the person reliably reports a history of cataplexy then the laboratory test is unnecessary as the person is sure to have narcolepsy. Even so, a laboratory test might be useful not to diagnose the illness, but to detect any abnormalities of the person's sleep process that might affect the doctor's recommendations for treatment or medication.
When the person arrives at the laboratory, they are prepared for a standard sleep recording. This preparation involves connecting the person to a special piece of equipment which will record the electrical signals which are present at various places on the body. More specifically, eight wires are attached to the scalp, behind the ears, the lower facial muscles and under the chin. To make these connections, a special jelly-like paste is used. Once the necessary connections are made, the person is then asked to lay down, get comfortable on a couch or bed, and to take a nap.
If the person has narcolepsy and has experienced both sleep attacks and the cataplexy, the equipment will usually pick up the electrical signals that confirm a diagnosis of narcolepsy. The laboratory test which confirms a diagnosis of narcolepsy is one in which sleep onset rapid eye movement (REM) is recorded. In normal persons, the sequence of events is always wakefulness to sleep with the maintenance of muscle activity and the absence of REM during approximately the first 60 minutes of a sleep period. In the narcoleptic, the first event is a complete suppression of normal muscle activity, followed quickly by REM. It is usually referred to as sleep onset REM and is a unique characteristic of narcolepsy. There are also other technical differences between the brainwaves of a person with narcolepsy and a person without the disorder.
Recently, researchers have begun to examine genetic and serologic correlates of narcolepsy in order to formulate more organically based diagnostic criteria. Due to this new genetic testing, determining whether a person is suffering from narcolepsy is almost as easy as taking a simple blood test.
In 1983, the group of Dr. Yutaka Honda in Japan was the first to discover a strong association between narcolepsy and the Human Leucocyte Antigen (HLA)-DR2 phenotype contained in the major histocompatibility complex located on the short arm of human chromosome six. These findings indicate the hereditary factor for narcolepsy. However, there is also evidence that there are some narcoleptics who meet current diagnostic criteria but do not have HLA-DR2. The HLA-DR2 phenotype is also strongly associated with other neurologic diseases stemming from autoimmune phenomena such as lupus erythematosus, rheumatoid arthritis, multiple sclerosis, and opti neuritis. An HLA-DR2 negative is not considered disconfirmatory in cases with unambiguous clinical and polysomnographic findings in favor of narcolepsy, and an HLA-DR2 positive cannot confirm narcolepsy without other positive data.
Ninety-five to 98 percent of all narcoleptic patients are HLA-DR2 positive. Further studies conducted at the Stanford University Center for Narcolepsy have now established that across all ethnic groups, the association is closest with a DQB1 allele, DQB1-0602 rather than with DR2, a gene that is found in eight to 35 percent of the control population in various ethnic groups. This is especially important in the black population in which DR2 is a poor marker for narcolepsy. The finding of an HLA association in narcolepsy suggests that the immune system is involved in the pathophysiology of the disease (most diseases with an HLA association are autoimmune in nature), or that an unidentified susceptibility gene located very close to the HLA DQ locus is involved. Since 1983, however, all attempts to demonstrate that human narcolepsy is an autoimmune disease have failed. The Stanford University Center for Narcolepsy states, "It has not been possible to demonstrate any inflammatory process in the central nervous system of narcoleptic patients and none of the systemic immune abnormalities usually found in autoimmune pathologies could be detected."
It has also been observed that animals sometimes have symptoms similar to those of narcolepsy in humans. Breeding and research projects using these naturally occurring animal models hold great promise for increasing understand of all aspects of narcolepsy, including genetic.
Obtaining an accurate diagnosis of a cause of narcolepsy from a local doctor is not always an easy task. A recent study of individuals with narcolepsy indicated that there was an average of 15 years between the appearance of the symptoms of narcolepsy and the correct medical diagnosis of narcolepsy. Of those diagnosed by the Stanford University Sleep Disorders Clinic as having narcolepsy, patients had seen an average of five doctors about their problems prior to receiving an accurate diagnosis.
Treatment depends upon the individuals' symptoms and history of therapy. Some individuals have more cataplexy, others more sleep attacks, and different treatment is indicated for each. Most important is that the treatment be tailored to the individual.
Analeptic medications are used to treat sleepiness and sleep attacks. Methamphetamines (such as Dsoxyn) and amphetamines (such as Dexedrine) are analeptic medications. Methylphenidate (Ritalin) is the preferred analptic medication used to treat sleep attacks and sleepiness.
Having a sleeping disorder such as narcolepsy can put a major strain on the sufferer's life and the lives of those around the patient. Living with narcolepsy is not an easy thing to do. Daily, routine functions become troublesome and problematic for narcolepsy patients. However, with continued research and education, it is hoped that more medical advances can be made in the near future to ease the daily living complications associated with the disease and a broader understanding from the general public can lend support and compassion to those suffering with the disorder.