Hypersomnias

Overview

Hypersomnia, or excessive daytime sleepiness, is a sleep disorder defined by excessive sleepiness. Beyond simply “feeling tired,” it’s a neurological or sleep-wake regulation problem that makes it difficult to stay awake, even after a full night’s sleep. People with hypersomnia often feel overwhelming sleep pressure, and often sleep 10 hours or more at night without feeling refreshed.

Hypersomnia can develop in one of two ways: on its own or as a symptom of other conditions. As such, sleep medicine specialists classify it into two main categories:

• Primary hypersomnia: In this type, extreme sleepiness occurs on its own, rather than as a symptom of another disorder. Examples include idiopathic hypersomnia, which has no clear cause, and narcolepsy, which happens when the brain can’t control its ability to stay awake.

• Secondary hypersomnia: In this type, another condition or an external factor leads to excessive sleepiness, such as:
  • Sleep disorders including sleep apnea, or restless leg syndrome (RLS)
  • Neurological conditions like multiple sclerosis, epilepsy, or brain injury
  • Autoimmune disorders like lupus
  • Viral infections affecting the brain or post-viral syndromes, such as long COVID
  • Depression or other mental health conditions
  • Medication side effects

In secondary hypersomnia, symptoms often improve upon successful treatment of the underlying cause.

Hypersomnia Symptoms

Hypersomnia is primarily an overwhelming feeling of sleepiness, but it can also involve a constellation of cognitive, behavioral, and sleep-wake symptoms.

People with hypersomnia may experience the following symptoms: 

• Excessive daytime sleepiness: An overwhelming need to sleep during the day, even after a full night of sleep, is a hallmark symptom of hypersomnia. It can manifest as sleepiness while reading, watching TV, or even while in meetings or class.
• Prolonged nighttime sleep: It’s common to wake up unrefreshed after getting 10-14 hours of sleep each night, too. 
• Difficulty waking up: Known as “sleep drunkenness,” you might feel confused, groggy, or disoriented for an especially long time after waking. 
• A frequent need to nap: To cope with the constant feeling of sleepiness, you might nap multiple times a day. While these naps tend to be long, unlike normal naps, they rarely improve alertness.
• Brain fog, slowed thinking, or mental fatigue: Slowed mental processing, poor concentration, forgetfulness, or difficulty completing tasks that require sustained attention are cognitive symptoms of hypersomnia. 
• Irritability or mood changes: Chronic sleepiness can lead to irritability, frustration, and even symptoms of depression or anxiety.
• Automatic behaviors: Some individuals with hypersomnia may briefly continue routine activities, such as writing, typing, or walking, while partially asleep with little memory of it afterward. 

If you are experiencing any of the symptoms outlined above, please arrange a visit with a healthcare professional to initiate diagnostic testing.

Hypersomnia Diagnosis

There is no single test that diagnoses hypersomnia on its own. Rather, your doctor will use multiple tools—a clinical evaluation, sleep tracking, and laboratory sleep studies, to name a few—to confirm excessive sleepiness while ruling out other disorders, such as narcolepsy or chronic fatigue syndrome.

Doctors use the following exams, tests, and imaging studies to diagnose hypersomnia:

• Physical and neurological exam: A detailed conversation with a sleep medicine specialist will help you understand your general sleep habits, daytime sleepiness, mental health, and any other medical conditions. Next, a neurological exam will evaluate your reflexes, coordination, balance, and cognitive function to help identify signs of neurological disorders that may affect sleep regulation.
• Sleep questionnaires: Standardized questionnaires, like sleep quality surveys and the Epworth Sleepiness Scale, can assess the severity of your sleepiness. 
• Medication and substance review: Your doctor will carefully review all medications and supplements that you use, along with recreational use of alcohol and other substances, to determine if they’re the cause of your excessive sleepiness or sedation. 
• Sleep diary: Keeping a daily log of sleep and wake times for at least one week, recording when you go to bed, when you fall asleep, when you wake, any naps you take, and how rested you feel, can provide important clues. This detailed tracking can help your sleep neurologist spot patterns that may suggest a sleep disorder like hypersomnia.
• Actigraphy: Actigraphy uses a watch-like device worn on the wrist to track your movements and light exposure. It also continuously records your sleep-wake activity for days or weeks to provide an objective view of your circadian rhythm.
• Overnight sleep study: Performed in a sleep laboratory, sensors will be placed on your scalp, face, chest, and legs to monitor your brain waves, breathing, heart rate, oxygen levels, and body movements during sleep. A sleep study also helps rule out other sleep disorders that might cause excessive sleepiness. 
• Multiple Sleep Latency Test (MSLT): The most important test for diagnosing hypersomnia, an MSLT is performed during the day after an overnight sleep study. In this test, you’ll take a scheduled nap every two hours while the test measures how quickly you fall asleep and whether you enter REM sleep more quickly than usual. 
• Maintenance of Wakefulness Test (MWT): This test measures how well you can stay awake while sitting quietly in a dim room for several sessions throughout the day. Your doctor will use this test to measure the severity of daytime sleepiness or to evaluate whether a specific treatment is working.
• Extended sleep monitoring: In suspected hypersomnia with no known cause, your sleep may be tracked for 24 to 32 hours in a lab or with extended actigraphy to determine whether you’re naturally sleeping more than 10 or 11 hours. 
• Blood tests: Blood tests can rule out medical conditions that can cause secondary hypersomnia, including thyroid disorders, anemia, infections, and metabolic problems.
• Magnetic Resonance Imaging (MRI) or Computed Tomography (CT) scan: If your provider suspects a neurological cause, an MRI or CT scan can identify structural problems like brain tumors, stroke damage, traumatic brain injury (TBI), and lesions affecting sleep-wake centers of your brain.

Ultimately, a careful, step-by-step approach is required to diagnose hypersomnia effectively and to rule out more common sleep disorders or conditions.

These treatments include:

• Low-sodium oxybate: As one of the first medications specifically approved for idiopathic hypersomnia, low-sodium oxybate is taken at night to improve the depth and quality of sleep. When nighttime sleep becomes more restorative, less daytime sleepiness is experienced. And, compared to older versions of oxybate medications, the low-sodium formulation reduces potential cardiovascular risks.
• Histamine-based wake-promoting medications: Targeting the brain’s histamine system reflects a more recent understanding that hypersomnia may involve reduced activity in certain wake-promoting neurotransmitter systems. Histamine plays an important role in maintaining wakefulness. Hence, increasing histamine activity in the brain promotes alertness without the uncomfortable side effects of traditional stimulants. 
• Dopamine-modulating wake-promoting medications: Newer wake-promoting drugs gently increase dopamine signaling in the brain to help regulate motivation, alertness, and attention. These medications also feature a lower risk of overstimulation when compared to classic stimulants.
• GABA-related experimental treatments: Researchers have found that some people with idiopathic hypersomnia have abnormal GABA activity, the brain’s sleep-promoting signaling system. This means their brains may be receiving stronger “sleep signals” than normal. Treatments that target abnormal GABA activity remain experimental. 

Meanwhile, traditional treatment for hypersomnia has long included:

• Stimulant medications: Your sleep specialist might prescribe drugs that increase activity in brain regions that regulate alertness when sleepiness is severe or not well-controlled by other treatments. 
• Medication adjustments: If certain medications are causing excessive sleepiness or sedation, your dosage may be adjusted, you may be advised to switch medications, or the timing of doses may be changed to reduce overall daytime drowsiness.
• Consistent sleep schedule: Maintaining a regular sleep routine—going to bed and waking up at the same time every day—helps stabilize your body’s internal clock and can reduce excessive sleepiness.
• Light exposure therapy: Exposure to bright light in the morning, whether from natural sunlight or a light therapy device, can help regulate your circadian rhythms and improve alertness.
• Lifestyle adjustments for alertness: Certain strategies can help you manage hypersomnia symptoms, like regular exercise, strategic caffeine use, and scheduling mentally demanding tasks during periods of higher alertness. In certain cases, providers may adjust your work schedule to avoid driving when extremely sleepy or plan rest periods to reduce potential safety risks.
• Scheduled daytime naps: Some people may benefit from short, scheduled naps to temporarily improve alertness.
• Treatment of underlying sleep disorders: If another sleep disorder causes hypersomnia, treating that condition often improves daytime sleepiness. For example, a device that keeps the airway open during sleep may restore normal sleep quality and reduce symptoms of hypersomnia.
• Treatment of underlying medical conditions: When hypersomnia is secondary to another illness, like neurological diseases, depression, or post-viral syndromes, treating the underlying condition can significantly improve symptoms. However, this approach isn’t a perfect fit for every underlying condition.

Living with the chronic sleepiness from hypersomnia can ultimately affect your mood, work, and daily functioning, so behavioral therapy may also help you or your loved one develop better coping strategies to manage the disorder’s emotional impact.