Hypersomnia is a sleep disorder that shares many similarities with narcolepsy in terms of symptoms. However, it lacks the classic triad of narcolepsy symptoms (cataplexy, a brief episodes of muscle weakness triggered by strong emotion, sleep paralysis, and hypnagogic hallucinations).
People with hypersomnia will often sleep in excess of 10 hours and are very difficult to wake during this time of sleep. Despite what would be considered an abundance of sleep for most people, they will still feel tired during the day, and may even want nap multiple times even at places or times that would not be considered socially acceptable. Like the prolonged sleep periods, these naps often provide only short periods of relief from the chronic tiredness, and another desired nap session will quickly approach.
Hypersomnia and excessive daytime sleepiness are complex traits whose formal study is in its infancy and whose socioeconomic burden is enormous. The term hypersomnolence is used to refer to excessive sleepiness during the day and hypersomnia as prolonged sleep periods (i.e., more than 10 hours per night). There are several different classification systems for the hypersomnia syndromes, but, broadly speaking, hypersomnia can be classified as primary or secondary, and the primary hypersomnias can be classified based on clusters of symptoms and test results or based on underlying cause.
Hypersomnia may be caused by other sleeping disorders, though these would generally be categorized as those particular sleeping disorders and not as hypersomnia. It may also be a case of genetics in some people, and could also be the cause of certain drugs or medications, neurological brain damage, or other medical disorders like fibromyalgia. In some cases, hypersomnia has no directly attributable cause and these cases are classified as idiopathic hypersomnia.
Hypersomnia is a relatively rare sleeping disorder, affecting under 1% of the population. It is slightly more common in females than in males, and typically starts in early adulthood. It is very rarely found in children.
- Hypersomnia may be caused by another sleep disorder (such as narcolepsy or sleep apnea), dysfunction of the autonomic nervous system, or drug or alcohol abuse.
- In some cases it results from a physical problem, such as a tumor, head trauma, or injury to the central nervous system.
- Certain medications, or medicine withdrawal, may also cause hypersomnia.
- Medical conditions including multiple sclerosis, depression, encephalitis, epilepsy, or obesity may contribute to the disorder.
- Some people appear to have a genetic predisposition to hypersomnia; in others, there is no known cause.
Types of Hypersomnia:
Secondary hypersomnia is judged to be “secondary” if it is caused by a problem with night time sleep, inability to get enough sleep, or other medical problems that result in sleepiness. For example, patients with obstructive sleep apnea, who have multiple interruptions in breathing throughout the night, are frequently sleepy during the day, but their hypersomnia is judged to be secondary to their sleep apnea. Secondary hypersomnia can be triggered by infections, depression, kidney failure, chronic fatigue syndrome, and neurodegenerative diseases such as Parkinson’s disease and myotonic dystrophy.
Primary hypersomnias, in contrast, occur in the absence of such medical problems and despite normal quality and quantity of night time sleep (and sometimes despite exceptionally long periods of night time sleep). The primary hypersomnias are thought to arise from problems with the brain’s systems that regulate sleep and wake.
Idiopathic hypersomnia (IH) is a sleep disorder in which people are excessively sleepy during the day independent of sleep duration. People with IH often wake feeling unrefreshed even after sleeping for long periods of time. They also have difficulty waking to alarms or external stimuli and may experience sleep inertia (difficulty moving and thinking after abrupt awakening) or confusional arousal.
One common classification of primary hypersomnia syndromes is that of the International Classification of Sleep Disorders, which divides hypersomnia syndromes primarily between narcolepsy, idiopathic hypersomnia, and the recurrent hypersomnias. Narcolepsy is further divided between that with cataplexy (brief episodes of muscle weakness triggered by strong emotion) and that without cataplexy. Idiopathic hypersomnia is characterized as having either long sleep time (greater than 10 hours/night) or normal sleep time.
The recurrent hypersomnias involve severe periods of sleepiness lasting days, interspersed with periods of more normal alertness, and include such entities as Kleine-Levin syndrome.
Kleine-Levin syndrome (KLS) is a rare disorder in which affected people experience episodes at least once per year during which they sleep for at least 11 hours out of every day (but often for days at a time), eat excessively (megaphagia), have abnormal thinking and behavior, and hypersexuality. Between episodes, their alertness, behavior, and thinking are normal.
Diagnosing hypersomnia will require some tests to make sure there are not other medical conditions or sleeping disorders causing the excessive sleepiness. A doctor may want you to maintain a sleep diary for one or more weeks before setting up these tests, and will also want to know the length of time the excessive daytime sleepiness has afflicted you for. A diagnosis of hypersomnia will probably not be made unless the offending symptoms have been around for at least three uninterrupted months with no apparent cause.
A polysomnogram and multiple sleep latency tests are both good tools in detecting hypersomnia or other sleeping disorders. The multiple sleep latency test measures the speed at which a person enters deep sleep over numerous 2 hour intervals. People with hypersomnia and other related disorders like narcolepsy tend to fall asleep very quickly, and this is considered the best test for detected these sleeping disorders. A multiple sleep latency test of less than 10 minutes may indicate one of the above sleeping disorders.
The polysomnogram test measures the subject’s brain waves and bodily movements during sleep phases, and this is good for detecting other sleep disorders that may be leading to the daytime sleepiness. If nothing abnormal is detected during this test, you may be asked to come back for a second test to validate the data, and barring changes in the results, it may be determined that you have hypersomnia.
Treatment for hypersomnia depends on the cause of the sleep disorder. For example, if you are diagnosed with sleep apnea, your doctor may prescribe a treatment known as continuous positive airway pressure (CPAP) to use when sleeping. With CPAP, you wear a mask over your nose that is hooked up to a machine that delivers a continuous flow of air into the nostrils. The pressure from air flowing into the nostrils helps keep the airways open.
If you are taking a medication that causes drowsiness, your doctor may suggest trying another drug instead. He or she may also suggest certain lifestyle modifications, such as going to bed earlier to try to get more sleep at night, and eliminating alcohol and caffeine consumption.
Your doctor can also prescribe various medications to treat hypersomnia.
These may include:
- Stimulants, such as methylphenidate (Ritalin) or modafinil (Provigil)
- Antidepressants, such as fluoxetine (Prozac), citalopram (Celexa), paroxetine (Paxil), sertraline (Zoloft)
- Sodium oxybate (Xyrem) is used to treat excessive daytime sleepiness associated with narcolepsy
Proper sleep hygiene is often the most important behavioral change that must be implemented. This includes setting a regular sleeping schedule, having a sleeping environment that is well suited to quality sleep, a comfortable bed and pillow, and avoiding caffeine or other stimulants near bedtime.
Some treatment plans may include an attempt at avoiding naps completely through the use of daytime stimulants, others will attempt to remove naps systematically, while others will encourage naps in balanced doses and at proper times and locations. How hypersomnia gets treated, and with what ultimate goal(s) in mind is up to the patient, and these should be ambitious yet realistic.
The prognosis for persons with hypersomnia depends on the cause of the disorder. While the disorder itself is not life threatening, it can have serious consequences, such as automobile accidents caused by falling asleep while driving. The attacks usually continue indefinitely.