Hypersomnia is a neurological disorder of excessive time spent sleeping or excessive sleepiness. It can have many possible causes (such as seasonal affective disorder) and can cause distress and problems with functioning. In the fifth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5), hypersomnolence, of which there are several subtypes, appears under sleep-wake disorders.
Hypersomnia is a pathological state characterized by a lack of alertness during the waking episodes of the day. It is not to be confused with fatigue, which is a normal physiological state. Daytime sleepiness appears most commonly during situations where little interaction is needed.
Since hypersomnia impairs patients' attention levels (wakefulness), quality of life may be impacted as well. This is especially true for people whose jobs request high levels of attention, such as in the healthcare field. which has occurred for at least 3 months prior to diagnosis.
Sleep drunkenness is also a symptom found in hypersomniac patients. It is a difficulty transitioning from sleep to wake.
It also appears in non-hypersomniac persons, for example after a night of insufficient sleep. Furthermore, 75% of the patients report that short naps are not refreshing either, compared to controls. After it is determined that excessive daytime sleepiness is present, a complete medical examination and full evaluation of potential disorders in the differential diagnosis (which can be tedious, expensive and time-consuming) should be undertaken. For example, if a patient with sleep apnea is treated with CPAP (continuous positive airway pressure), which resolves their apneas but not their excessive daytime sleepiness, it is necessary to seek other causes for the excessive daytime sleepiness. Obstructive sleep apnea "occurs frequently in narcolepsy and may delay the diagnosis of narcolepsy by several years and interfere with its proper management."
Primary hypersomnias
The true primary hypersomnias include: Additionally, head trauma can be associated with a primary/central hypersomnia, and symptoms similar to those of idiopathic hypersomnia can be seen within 6–18 months following the trauma. However, the associated symptoms of headaches, memory loss, and lack of concentration may be more frequent in head trauma than in idiopathic hypersomnia. "The possibility of secondary narcolepsy following head injury in previously asymptomatic individuals has also been reported."
Sleep apnea is the second most frequent cause of secondary hypersomnia, affecting up to 4% of middle-aged adults, mostly men. Upper airway resistance syndrome (UARS) is a clinical variant of sleep apnea that can also cause hypersomnia. "Other sleep alterations, such as periodic limb movement disorders in patients with spinal cord disease, have also been uncovered with the widespread use of polysomnography." Polysomnography shows reduced sleep efficiency and may include alpha intrusion into sleep EEG. ME/CFS can be comorbid with sleep disorders such as narcolepsy, sleep apnea, PLMD, etc.
As with chronic fatigue syndrome, fibromyalgia may be associated with anomalous alpha wave activity (typically associated with arousal states) during NREM sleep. Also, researchers have shown that disrupting stage IV sleep consistently in young, healthy subjects causes a significant increase in muscle tenderness—similar to that experienced in "neurasthenic musculoskeletal pain syndrome". This pain resolved when the subjects were able to resume their normal sleep patterns.
Chronic kidney disease is commonly associated with sleep symptoms and excessive daytime sleepiness. 80% of those on dialysis have sleep disturbances. Sleep apnea can occur 10 times as often in uremic patients than in the general population and can affect up to 30-80% of patients on dialysis, though nighttime dialysis can improve this. About 50% of dialysis patients have hypersomnia, as severe kidney disease can cause uremic encephalopathy, increased sleep-inducing cytokines, and impaired sleep efficiency. About 70% of dialysis patients are affected by insomnia, and RLS and PLMD affect 30%, though these may improve after dialysis or kidney transplant.
Most forms of cancer and their therapies can cause fatigue and disturbed sleep, affecting 25-99% of patients and often lasting for years after treatment completion. "Insomnia is common and a predictor of fatigue in cancer patients, and polysomnography demonstrates reduced sleep efficiency, prolonged initial sleep latency, and increased wake time during the night." Paraneoplastic syndromes can also cause insomnia, hypersomnia, and parasomnias. There are also some case reports of central hypersomnia in celiac disease. And RLS "has been shown to be frequent in celiac disease," presumably due to its associated iron deficiency. Researchers found that the level of sleepiness is correlated with the severity of the injury. Even if patients reported an improvement, sleepiness remained present for a year in about a quarter of patients with traumatic brain injury. These episodes can occur weeks or months apart from each other.
Kleine-Levin syndrome is characterized by the association of episodes of hypersomnias with behavioral, cognitive and mood abnormalities. The behavioral disturbances can be composed of hyperphagia, irritability, or sexual disinhibition. Unlike Kleine-Levin syndrome, hyperphagia and hypersexuality are not reported in people with menstrual-related hypersomnia, but hypophagia could be present. Ordinarily, these episodes appear 2 weeks before menstruation. It comprises a lot of electrodes which measure physiological variables related to sleep. Polysomnography often includes electroencephalography, electromyography, electrocardiography, muscle activity and respiratory function.
Polysomnography is helpful to identify the very short sleep onset latency period, the very efficient sleep (more than 90%), the increased slow wave sleep, and sometimes an elevated amount of sleep spindles in idiopathic hypersomnia patients.
Multiple sleep latency test (MSLT)
The 'multiple sleep latency test' (MSLT) is an objective tool which indicates the degree of sleepiness by measuring the sleep latency (i.e. the speed of falling asleep). It also gives information regarding the presence of abnormal REM sleep onset episodes.
The MSLT is often administered the day after recording the polysomnography, and the mean sleep latency score is often found to be around (or less than) 8 minutes in idiopathic hypersomnia patients. In order to report them, the patient has to wear continuously a device on his or her wrist, which looks like a watch and does not contain any electrodes.
The advantage actigraphy shows over polysomnography is that it is possible to record for 24-hours a day for weeks. Actigraphy is also helpful in ruling out other sleep disorders, especially circadian disorders, leading to an excess of sleepiness during the day, too.
The maintenance of wakefulness test (MWT)
The 'maintenance of wakefulness test' (MWT) is a test that measures the ability to stay awake. It is used to diagnose disorders of excessive somnolence, such as hypersomnia, narcolepsy or obstructive sleep apnea. During that test, patients sit comfortably and are instructed to try to stay awake. For each statement, patients report their level of sleepiness using a 7-point scale, going from very alert to excessively sleepy. Researchers found that the SSS was highly correlated with performances to monotonous and boring tasks, which are found to be very sensitive to sleepiness. The patients have to rate specific daily situations by means of a scale going from 0 (would never doze) to 3 (high chance of dozing). The results found in the ESS correlate with the sleep latency indicated by the Multiple Sleep Latency Test.
Treatment
Although there has been no cure of chronic hypersomnia, there are several treatments that may improve patients' quality of life—depending on the specific cause or causes of hypersomnia that are diagnosed. Behavioral treatments, as well as sleep hygiene, have to be discussed with the patient and are recommended.
There are several pharmacological agents that have been prescribed to patients with hypersomnia, but few have been found to be efficient. The dosage is started at 100 mg per day, and then slowly increased to 400 mg per day.
In general, patients with hypersomnia or excessive sleepiness should only go to bed to sleep or for sexual activity. All other activities, such as eating or watching television, should be done elsewhere. "with a higher prevalence for men due to the sleep apnea syndromes".