How is hypersomnia diagnosed?
Your sleep specialist will ask about your symptoms, medical history, sleep history and current medications. You may be asked to keep track of your sleep and wake patterns using a sleep diary. You may be asked to wear an actigraphy sensor, which is a small, watch-like device worn on your wrist that can track disruptions in your sleep-wake cycle over several weeks.
Other tests your sleep specialist may order include:
- Polysomnography. This overnight sleep study test measures your brain waves, breathing pattern, heart rhythms and muscle movements during stages of sleep. The test is performed in a hospital, sleep study center or other designated site and under the direct supervision of a trained sleep specialist. This test helps diagnose disorders believed to cause sleepiness.
- Multiple sleep latency test. This daytime sleep test measures a person’s tendency to fall asleep during five, 20-minute nap trials scheduled two hours apart. The test records brain activity, including the number of naps containing REM sleep.
- Sleep questionnaires. You may be asked to complete one or more sleep questionnaires that ask you to rate your sleepiness. Popular sleep questionnaires are the Epworth Sleepiness Scale and the Stanford Sleepiness Scale.
According to diagnostic criteria from the Diagnostic and Statistical Manual of Mental Disorders, you would be diagnosed with hypersomnia if you:
- Experience excessive sleepiness despite at least seven hours of sleep and have at least one of these additional symptoms: (a) lapse into sleep several times within the same day; (b) get more than nine hours of sleep and still don’t feel refreshed and awake; or (c) don’t feel fully awake after an abrupt awakening.
- Experience hypersomnia at least three times a week for at least three months.
- Report that the hypersomnia is causing significant distress or impairment in your mental, social, work or other areas of functioning.
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Are there different types of hypersomnias?
Different sleep organizations and psychiatric organizations have different classification systems and subcategories for hypersomnia. Complicating matters, these classifications continue to evolve.
More commonly accepted criteria is that there are two main types of hypersomnia: secondary hypersomnia and primary hypersomnia.
Secondary hypersomnia
Secondary hypersomnia means your excessive sleepiness is due to some other known cause. Causes include:
- Hypersomnia due to a medical condition. Diseases and conditions that can cause hypersomnia include epilepsy, hypothyroidism, encephalitis, multiple sclerosis, Parkinson’s disease, obesity, obstructive sleep apnea, delayed sleep phase syndrome, multiple systems atrophy, myotonic dystrophy and other genetic disorders, mood disorders (including depression, bipolar disorder, seasonal depression). Hypersomnia can also result from head trauma, tumors and central nervous system diseases.
- Hypersomnia due to medications or alcohol. Sedating medications (includes benzodiazepines, barbiturates, melatonin and sleeping aids), anti-hypertensive drugs, anti-epileptic drugs, anti-parkinsonian agents, skeletal muscle relaxants, antipsychotics, opiates, cannabis and alcohol can cause hypersomnia. Withdrawal from stimulant drugs (includes medications used to treat attention deficit hyperactivity disorder) can cause hypersomnia.
- Hypersomnia due to not getting enough sleep (insufficient sleep syndrome). You may have hypersomnia simply because you're not going to bed and allowing yourself the chance for seven to nine hours of sleep (for adults). Perhaps you're not practicing good sleep habits (like avoiding exercise and caffeine within a few hours of bedtime) to help you get enough quality sleep.
Primary hypersomnia
Primary hypersomnia means that hypersomnia is its own condition. It’s not caused by other medical conditions or a symptom of another medical condition. Four conditions are classified as primary hypersomnias:
- Narcolepsy type 1. This type of narcolepsy, also called narcolepsy with cataplexy (sudden muscle weakness triggered by emotions) is caused by having a low level of the brain and cerebrospinal fluid chemical (neurotransmitter) hypocretin (also called orexin). Daytime naps are usually shorter and refreshing compared with daytime naps in other disorders of hypersomnolence. Narcolepsy type 1 commonly begins between the ages of 10 and 25. Hallucinations and sleep paralysis are common.
- Narcolepsy type 2. This type of narcolepsy doesn’t include cataplexy. Narcolepsy type 2 has less severe symptoms and normal levels of hypocretin. Narcolepsy type 2 commonly begins during adolescence.
- Kleine-Levin syndrome. This condition consists of recurring episodes of extreme hypersomnia. It usually occurs with mental, behavioral and sometimes psychiatric disturbances. Each episode can last for about 10 days, with some episodes lasting several weeks to months and recurring several times a year. If you have Kleine-Levin syndrome, you have normal alertness and functioning between episodes. It mainly affects young males. Episodes decrease over eight to 12 years.
- Idiopathic hypersomnia. Idiopathic means no known cause, so idiopathic hypersomnia means you feel extremely sleepy for unknown reasons — even after a longer than the adequate amount (9 to 10 hours) of sleep.
