hypersomnolence
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Hypersomnia is a
neurological disorder A neurological disorder is any disorder of the nervous system. Structural, biochemical or electrical abnormalities in the brain, spinal cord or other nerves can result in a range of symptoms. Examples of symptoms include paralysis, muscle weakn ...
of excessive time spent sleeping or
excessive sleepiness Excessive daytime sleepiness (EDS) is characterized by persistent sleepiness and often a general lack of energy, even during the day after apparently adequate or even prolonged nighttime sleep. EDS can be considered as a broad condition encompass ...
. 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 The ''Diagnostic and Statistical Manual of Mental Disorders'' (DSM; latest edition: DSM-5-TR, published in March 2022) is a publication by the American Psychiatric Association (APA) for the classification of mental disorders using a common langua ...
'' (
DSM-5 The ''Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition'' (DSM-5), is the 2013 update to the ''Diagnostic and Statistical Manual of Mental Disorders'', the taxonomic and diagnostic tool published by the American Psychiatric ...
), 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.American Academy of Sleep Medicine. The international classification of sleep disorders: diagnostic & coding manual (2nd ed). Westchester, IL: American Academy of Sleep Medicine, 2005. It is not to be confused with
fatigue Fatigue describes a state of tiredness that does not resolve with rest or sleep. In general usage, fatigue is synonymous with extreme tiredness or exhaustion that normally follows prolonged physical or mental activity. When it does not resolve ...
, which is a normal physiological state. Daytime sleepiness appears most commonly during situations where little interaction is needed. Since the patients’ attention levels (
wakefulness Wakefulness is a daily recurring Human brain, brain state and state of consciousness in which an individual is conscious and engages in coherent cognition, cognitive and behavioral responses to the external world. Being awake is the opposite of ...
) are impaired, their quality of life may be impacted as well.Morgenthaler, T. I., Kapur, V. K., Brown, T. M., Swick, T. J., Alessi, C., Aurora, R. N., … Zak, R. (2007). Practice Parameters for the Treatment of Narcolepsy and other Hypersomnias of Central Origin. ''Sleep, 30''(12), 1705‑1711. https://doi.org/10.1093/sleep/30.12.1705 This is especially true for people whose jobs request high levels of attention, such as in the healthcare field.


Symptoms

The main symptom of hypersomnia is
excessive daytime sleepiness Excessive daytime sleepiness (EDS) is characterized by persistent sleepiness and often a general lack of energy, even during the day after apparently adequate or even prolonged nighttime sleep. EDS can be considered as a broad condition encompass ...
(EDS), or prolonged nighttime sleep, which has occurred for at least 3 months prior to diagnosis. Sleep drunkenness is also a symptom found in hypersomniac patients.Roth, B. (1972). Hypersomnia With « Sleep Drunkenness ». ''Archives of General Psychiatry, 26''(5), 456. https://doi.org/10.1001/archpsyc.1972.01750230066013Trotti, L. M. (2017). Waking up is the hardest thing I do all day: Sleep inertia and sleep drunkenness. ''Sleep medicine reviews, 35'', 76–84. It is a difficulty transitioning from sleep to wake. Individuals experiencing sleep drunkenness report waking with confusion, disorientation, slowness and repeated returns to sleep. It also appears in non-hypersomniac persons, for example after a night of insufficient sleep. Fatigue and consumption of alcohol or hypnotics can cause sleep drunkenness as well. It is also associated with irritability: people who get angry shortly before sleeping tend to experience sleep drunkenness. According to the
American Academy of Sleep Medicine The American Academy of Sleep Medicine (AASM) is a United States professional society for the medical subspecialty of sleep medicine which includes disorders of circadian rhythms. It was established in 1975. The organization's functions include t ...
, hypersomniac patients often take long naps during the day that are mostly unrefreshing. Researchers found that naps are usually more frequent and longer in patients than in controls.Vernet, C., Leu-Semenescu, S., Buzare, M.-A., & Arnulf, I. (2010). Subjective symptoms in idiopathic hypersomnia: Beyond excessive sleepiness. ''Journal of sleep research, 19''(4), 525–534. Furthermore, 75% of the patients report that short naps are not refreshing, compared to controls.


Diagnosis

"The severity of daytime sleepiness needs to be quantified by subjective scales (at least the
Epworth Sleepiness Scale The Epworth Sleepiness Scale (ESS) is a scale intended to measure daytime sleepiness that is measured by use of a very short questionnaire. This can be helpful in diagnosing sleep disorders. It was introduced in 1991 by Dr Murray Johns of Epwort ...
) and objective tests such as the multiple sleep latency test (MSLT)." The
Stanford sleepiness scale The Stanford Sleepiness Scale (SSS), developed by William C. Dement and colleagues in 1972, is a one-item self-report questionnaire measuring levels of sleepiness throughout the day. The scale, which can be administered in 1–2 minutes, is gener ...
(SSS) is another frequently-used subjective measurement of sleepiness. 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.


Differential diagnosis

Hypersomnia can be primary (of central/brain origin), or it can be secondary to any of numerous medical conditions. More than one type of hypersomnia can coexist in a single patient. Even in the presence of a known cause of hypersomnia, the contribution of this cause to the complaint of excessive daytime sleepiness needs to be assessed. When specific treatments of the known condition do not fully suppress excessive daytime sleepiness, additional causes of hypersomnia should be sought. 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 Obstructive sleep apnea (OSA) is the most common sleep-related breathing disorder and is characterized by recurrent episodes of complete or partial obstruction of the upper airway leading to reduced or absent breathing during sleep. These episod ...
"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: * Narcolepsy (with and without cataplexy) * Idiopathic hypersomnia * Recurrent hypersomnias (like Kleine-Levin syndrome)


Primary hypersomnia mimics

There are also several genetic disorders that may be associated with primary/central hypersomnia. These include the following: Prader-Willi syndrome;
Norrie disease Norrie disease is a rare disease and genetic disorder that primarily affects the eyes and almost always leads to blindness. It is caused by mutations in the ''Norrin cystine knot growth factor (NDP)'' gene, which is located on the X chromosome. In ...
;
Niemann–Pick disease, type C Niemann–Pick type C (NPC) (colloquially, "Childhood Alzheimer's") is a lysosomal storage disease associated with mutations in NPC1 and NPC2 genes. Niemann–Pick type C affects an estimated 1:150,000 people. Approximately 50% of cases present b ...
; and
myotonic dystrophy Myotonic dystrophy (DM) is a type of muscular dystrophy, a group of genetic disorders that cause progressive muscle loss and weakness. In DM, muscles are often unable to relax after contraction. Other manifestations may include cataracts, intel ...
. However, hypersomnia in these syndromes may also be associated with other secondary causes, so it is important to complete a full evaluation. Myotonic dystrophy is often associated with SOREMPs ( sleep onset REM periods, such as occur in narcolepsy). There are many neurological disorders that may mimic the primary hypersomnias, narcolepsy and idiopathic hypersomnia:
brain tumors A brain tumor occurs when abnormal cells form within the brain. There are two main types of tumors: malignant tumors and benign (non-cancerous) tumors. These can be further classified as primary tumors, which start within the brain, and secondar ...
; stroke-provoking lesions; and dysfunction in the
thalamus The thalamus (from Greek θάλαμος, "chamber") is a large mass of gray matter located in the dorsal part of the diencephalon (a division of the forebrain). Nerve fibers project out of the thalamus to the cerebral cortex in all directions, ...
,
hypothalamus The hypothalamus () is a part of the brain that contains a number of small nuclei with a variety of functions. One of the most important functions is to link the nervous system to the endocrine system via the pituitary gland. The hypothalamu ...
, or
brainstem The brainstem (or brain stem) is the posterior stalk-like part of the brain that connects the cerebrum with the spinal cord. In the human brain the brainstem is composed of the midbrain, the pons, and the medulla oblongata. The midbrain is cont ...
. Also, neurodegenerative conditions such as
Alzheimer's disease Alzheimer's disease (AD) is a neurodegeneration, neurodegenerative disease that usually starts slowly and progressively worsens. It is the cause of 60–70% of cases of dementia. The most common early symptom is difficulty in short-term me ...
,
Parkinson's disease Parkinson's disease (PD), or simply Parkinson's, is a long-term degenerative disorder of the central nervous system that mainly affects the motor system. The symptoms usually emerge slowly, and as the disease worsens, non-motor symptoms becom ...
, or
multiple system atrophy Multiple system atrophy (MSA) is a rare neurodegenerative disorder characterized by autonomic dysfunction, tremors, slow movement, muscle rigidity, and postural instability (collectively known as parkinsonism) and ataxia. This is caused by progr ...
are frequently associated with primary hypersomnia. However, in these cases, one must still rule out other secondary causes. Early
hydrocephalus Hydrocephalus is a condition in which an accumulation of cerebrospinal fluid (CSF) occurs within the brain. This typically causes increased intracranial pressure, pressure inside the skull. Older people may have headaches, double vision, poor ...
can also cause severe excessive daytime sleepiness. 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."


Secondary hypersomnias

Secondary hypersomnias are extremely numerous. Hypersomnia can be secondary to disorders such as
clinical depression Major depressive disorder (MDD), also known as clinical depression, is a mental disorder characterized by at least two weeks of pervasive low mood, low self-esteem, and loss of interest or pleasure in normally enjoyable activities. Introdu ...
,
multiple sclerosis Multiple (cerebral) sclerosis (MS), also known as encephalomyelitis disseminata or disseminated sclerosis, is the most common demyelinating disease, in which the insulating covers of nerve cells in the brain and spinal cord are damaged. This d ...
,
encephalitis Encephalitis is inflammation of the brain. The severity can be variable with symptoms including reduction or alteration in consciousness, headache, fever, confusion, a stiff neck, and vomiting. Complications may include seizures, hallucinations, ...
,
epilepsy Epilepsy is a group of non-communicable neurological disorders characterized by recurrent epileptic seizures. Epileptic seizures can vary from brief and nearly undetectable periods to long periods of vigorous shaking due to abnormal electrical ...
, or
obesity Obesity is a medical condition, sometimes considered a disease, in which excess body fat has accumulated to such an extent that it may negatively affect health. People are classified as obese when their body mass index (BMI)—a person's we ...
. Hypersomnia can also be a symptom of other sleep disorders, like sleep apnea. It may occur as an
adverse effect An adverse effect is an undesired harmful effect resulting from a medication or other intervention, such as surgery. An adverse effect may be termed a "side effect", when judged to be secondary to a main or therapeutic effect. The term complica ...
of taking certain medications, of withdrawal from some medications, or of substance use. A genetic predisposition may also be a factor. In some cases it results from a physical problem, such as a tumor, head trauma, or dysfunction of the autonomic or
central nervous system The central nervous system (CNS) is the part of the nervous system consisting primarily of the brain and spinal cord. The CNS is so named because the brain integrates the received information and coordinates and influences the activity of all par ...
. 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. Just as other sleep disorders (like narcolepsy) can coexist with sleep apnea, the same is true for UARS. There are many cases of UARS in which excessive daytime sleepiness persists after CPAP treatment, indicating an additional cause, or causes, of the hypersomnia and requiring further evaluation. Sleep movement disorders, such as restless legs syndrome (RLS) and periodic limb movement disorder (PLMD or PLMS) can also cause secondary hypersomnia. Although RLS does commonly cause excessive daytime sleepiness, PLMS does not. There is no evidence that PLMS plays "a role in the etiology of daytime sleepiness. In fact, two studies showed no correlation between PLMS and objective measures of excessive daytime sleepiness. In addition, EDS in these patients is best treated with psychostimulants—and not with dopaminergic agents known to suppress PLMS." Neuromuscular diseases and
spinal cord diseases The spinal cord is a long, thin, tubular structure made up of nervous tissue, which extends from the medulla oblongata in the brainstem to the lumbar region of the vertebral column (backbone). The backbone encloses the central canal of the spi ...
often lead to sleep disturbances due to respiratory dysfunction causing sleep apnea, and they may also cause
insomnia Insomnia, also known as sleeplessness, is a sleep disorder in which people have trouble sleeping. They may have difficulty falling asleep, or staying asleep as long as desired. Insomnia is typically followed by daytime sleepiness, low energy, ...
related to pain. "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." Primary hypersomnia in
diabetes Diabetes, also known as diabetes mellitus, is a group of metabolic disorders characterized by a high blood sugar level ( hyperglycemia) over a prolonged period of time. Symptoms often include frequent urination, increased thirst and increased ap ...
,
hepatic encephalopathy Hepatic encephalopathy (HE) is an altered level of consciousness as a result of liver failure. Its onset may be gradual or sudden. Other symptoms may include movement problems, changes in mood, or changes in personality. In the advanced stages ...
, and
acromegaly Acromegaly is a disorder that results from excess growth hormone (GH) after the growth plates have closed. The initial symptom is typically enlargement of the hands and feet. There may also be an enlargement of the forehead, jaw, and nose. Other ...
is rarely reported, but these medical conditions may also be associated with hypersomnia secondary to sleep apnea and periodic limb movement disorder (PLMD).
Chronic fatigue syndrome Chronic fatigue syndrome (CFS), also called myalgic encephalomyelitis (ME) or ME/CFS, is a complex, debilitating, long-term medical condition. The causes and mechanisms of the disease are not fully understood. Distinguishing core symptoms are ...
and
fibromyalgia Fibromyalgia (FM) is a medical condition defined by the presence of chronic widespread pain, fatigue, waking unrefreshed, cognitive symptoms, lower abdominal pain or cramps, and depression. Other symptoms include insomnia and a general hyp ...
can also be associated with hypersomnia. Chronic fatigue syndrome is "characterized by persistent or relapsing fatigue that does not resolve with sleep or rest. Polysomnography shows reduced sleep efficiency and may include alpha intrusion into sleep
EEG Electroencephalography (EEG) is a method to record an electrogram of the spontaneous electrical activity of the brain. The biosignals detected by EEG have been shown to represent the postsynaptic potentials of pyramidal neurons in the neocortex ...
. It is likely that a number of cases labeled as chronic fatigue syndrome are unrecognized cases of upper airway resistance syndrome" or other sleep disorders, such as narcolepsy, sleep apnea, PLMD, etc. As with chronic fatigue syndrome,
fibromyalgia Fibromyalgia (FM) is a medical condition defined by the presence of chronic widespread pain, fatigue, waking unrefreshed, cognitive symptoms, lower abdominal pain or cramps, and depression. Other symptoms include insomnia and a general hyp ...
may be associated with anomalous alpha wave activity (typically associated with arousal states) during
NREM Non-rapid eye movement sleep (NREM), also known as quiescent sleep, is, collectively, sleep stages 1–3, previously known as stages 1–4. Rapid eye movement sleep (REM) is not included. There are distinct electroencephalographic and other char ...
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 Chronic kidney disease (CKD) is a type of kidney disease in which a gradual loss of kidney function occurs over a period of months to years. Initially generally no symptoms are seen, but later symptoms may include leg swelling, feeling tired, vo ...
is commonly associated with sleep symptoms and excessive daytime sleepiness. 80% of those on
dialysis Dialysis may refer to: *Dialysis (chemistry), a process of separating molecules in solution **Electrodialysis, used to transport salt ions from one solution to another through an ion-exchange membrane under the influence of an applied electric pote ...
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 Cytokines are a broad and loose category of small proteins (~5–25 kDa) important in cell signaling. Cytokines are peptides and cannot cross the lipid bilayer of cells to enter the cytoplasm. Cytokines have been shown to be involved in autocrin ...
, 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.
Autoimmune disease An autoimmune disease is a condition arising from an abnormal immune response to a functioning body part. At least 80 types of autoimmune diseases have been identified, with some evidence suggesting that there may be more than 100 types. Nearly a ...
s, especially
lupus Lupus, technically known as systemic lupus erythematosus (SLE), is an autoimmune disease in which the body's immune system mistakenly attacks healthy tissue in many parts of the body. Symptoms vary among people and may be mild to severe. Comm ...
and
rheumatoid arthritis Rheumatoid arthritis (RA) is a long-term autoimmune disorder that primarily affects joints. It typically results in warm, swollen, and painful joints. Pain and stiffness often worsen following rest. Most commonly, the wrist and hands are involv ...
, are often associated with hypersomnia. Morvan's syndrome is an example of a rarer autoimmune illness that can also lead to hypersomnia. Celiac disease is another autoimmune disease associated with poor sleep quality (which may lead to hypersomnia), "not only at diagnosis but also during treatment with a gluten-free diet." 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.
Hypothyroidism Hypothyroidism (also called ''underactive thyroid'', ''low thyroid'' or ''hypothyreosis'') is a disorder of the endocrine system in which the thyroid gland does not produce enough thyroid hormone. It can cause a number of symptoms, such as po ...
and iron deficiency with or without (iron-deficiency
anemia Anemia or anaemia (British English) is a blood disorder in which the blood has a reduced ability to carry oxygen due to a lower than normal number of red blood cells, or a reduction in the amount of hemoglobin. When anemia comes on slowly, th ...
) can also cause secondary hypersomnia. Various tests for these disorders are done so they can be treated. Hypersomnia can also develop within months after viral infections such as Whipple's disease, mononucleosis,
HIV The human immunodeficiency viruses (HIV) are two species of ''Lentivirus'' (a subgroup of retrovirus) that infect humans. Over time, they cause acquired immunodeficiency syndrome (AIDS), a condition in which progressive failure of the immune ...
, and Guillain–Barré syndrome. Behaviorally induced insufficient sleep syndrome must be considered in the differential diagnosis of secondary hypersomnia. This disorder occurs in individuals who fail to get sufficient sleep for at least three months. In this case, the patient has
chronic sleep deprivation Sleep deprivation, also known as sleep insufficiency or sleeplessness, is the condition of not having adequate duration and/or quality of sleep to support decent alertness, performance, and health. It can be either chronic or acute and may vary ...
, although they may not necessarily be aware of it. This situation is becoming more prevalent in western society due to the modern demands and expectations placed upon the individual. Many
medication A medication (also called medicament, medicine, pharmaceutical drug, medicinal drug or simply drug) is a drug used to diagnose, cure, treat, or prevent disease. Drug therapy (pharmacotherapy) is an important part of the medical field and re ...
s can lead to secondary hypersomnia. Therefore, a patient's complete medication list should be carefully reviewed for sleepiness or fatigue as side effects. In these cases, careful withdrawal from the possibly offending medication(s) is needed; then, medication substitution can be undertaken. Mood disorders, like depression,
anxiety disorder Anxiety disorders are a cluster of mental disorders characterized by significant and uncontrollable feelings of anxiety and fear such that a person's social, occupational, and personal function are significantly impaired. Anxiety may cause physi ...
and
bipolar disorder Bipolar disorder, previously known as manic depression, is a mental disorder characterized by periods of depression and periods of abnormally elevated mood that last from days to weeks each. If the elevated mood is severe or associated with ...
, can also be associated with hypersomnia. The complaint of excessive daytime sleepiness in these conditions is often associated with poor sleep at night. "In that sense, insomnia and EDS are frequently associated, especially in cases of depression." Hypersomnia in mood disorders seems to be primarily related to "lack of interest and decreased energy inherent in the depressed condition rather than an increase in sleep or REM sleep propensity". In all cases with these mood disorders, the MSLT is normal (not too short and no SOREMPs).


Posttraumatic hypersomnias

In some cases, hypersomnia can be caused by a brain injury. Researchers found that the level of sleepiness is correlated with the severity of the injury.Watson, N. F., Dikmen, S., Machamer, J., Doherty, M., & Temkin, N. (2007). Hypersomnia following traumatic brain injury. ''Journal of Clinical Sleep Medicine, 3''(04), 363–368. Even if patients reported an improvement, sleepiness remained present for a year in about a quarter of patients with traumatic brain injury.


Recurrent hypersomnias

Recurrent hypersomnias are defined by several episodes of hypersomnia persisting from a few days to weeks.Dauvilliers, Y., & Buguet, A. (2005). Hypersomnia. ''Dialogues in clinical neuroscience, 7''(4), 347. These episodes can occur weeks or months apart from each other. There are 2 subtypes of recurrent hypersomnias: Kleine-Levin syndrome and menstrual-related hypersomnia.Billiard, M., & Podesta, C. (2013). Recurrent hypersomnia following traumatic brain injury. ''Sleep Medicine, 14''(5), 462‑465. https://doi.org/10.1016/j.sleep.2013.01.009 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. The cognitive disorders consist of confusion, hallucinations or delusions. Mood symptoms are characterized by anxiety or depression. Menstrual-related hypersomnia is characterized by episodes of excessive sleepiness associated with the menstrual cycle. Researchers found that the degree of premenstrual symptoms were correlated with daytime sleepiness. Unlike Kleine-Levin syndrome, hyperphagia and hypersexuality are not reported in people with menstrual-related hypersomnia, but
hypophagia Anorexia is a medical term for a loss of appetite. While the term in non-scientific publications is often used interchangeably with anorexia nervosa, many possible causes exist for a loss of appetite, some of which may be harmless, while others ...
could be present.Harris, S. F., Monderer, R. S., & Thorpy, M. (2012). Hypersomnias of Central Origin. Neurologic Clinics, 30(4), 1027‑1044. https://doi.org/10.1016/j.ncl.2012.08.002 Ordinarily, these episodes appear 2 weeks before menstruation. A few studies have attested that some hormones as
prolactin Prolactin (PRL), also known as lactotropin, is a protein best known for its role in enabling mammals to produce milk. It is influential in over 300 separate processes in various vertebrates, including humans. Prolactin is secreted from the pit ...
and
progesterone Progesterone (P4) is an endogenous steroid and progestogen sex hormone involved in the menstrual cycle, pregnancy, and embryogenesis of humans and other species. It belongs to a group of steroid hormones called the progestogens and is the m ...
could be responsible for Menstrual-Related Hypersomnia. Therefore, different contraceptive pills could improve the symptoms. The sleep architecture changes. There is a decrease of
slow-wave sleep Slow-wave sleep (SWS), often referred to as deep sleep, consists of stage three of non-rapid eye movement sleep. It usually lasts between 70 and 90 minutes and takes place during the first hours of the night. Initially, SWS consisted of both St ...
and an increase of slow-Theta-wave activity.


Assessment tools


Polysomnography

Polysomnography is an objective sleep assessment method. It comprises a lot of electrodes which measure physiological variables related to sleep.Marino, M., Li, Y., Rueschman, M. N., Winkelman, J. W., Ellenbogen, J. M., Solet, J. M., … Buxton, O. M. (2013). Measuring sleep: Accuracy, sensitivity, and specificity of wrist actigraphy compared to polysomnography. ''Sleep, 36''(11), 1747–1755. Polysomnography often includes
electroencephalography Electroencephalography (EEG) is a method to record an electrogram of the spontaneous electrical activity of the brain. The biosignals detected by EEG have been shown to represent the postsynaptic potentials of pyramidal neurons in the neocortex ...
,
electromyography Electromyography (EMG) is a technique for evaluating and recording the electrical activity produced by skeletal muscles. EMG is performed using an instrument called an electromyograph to produce a record called an electromyogram. An electromyog ...
,
electrocardiography Electrocardiography is the process of producing an electrocardiogram (ECG or EKG), a recording of the heart's electrical activity. It is an electrogram of the heart which is a graph of voltage versus time of the electrical activity of the hear ...
, 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).Carskadon, M. A. (1986). Guidelines for the multiple sleep latency test (MSLT): A standard measure of sleepiness. ''Sleep, 9''(4), 519–524.Littner, M. R., Kushida, C., Wise, M., G. Davila, D., Morgenthaler, T., Lee-Chiong, T., … Berry, R. B. (2005). Practice parameters for clinical use of the multiple sleep latency test and the maintenance of wakefulness test. ''Sleep, 28''(1), 113–121. It also gives information regarding the presence of abnormal REM sleep onset episodes. During that test, patients have a series of opportunities to sleep at 2-h intervals across the day in a darkened room and with no external alerting influences. 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. Some patients might even have a sleep onset latency of 5 minutes or less. These patients are often even more aware of sleeping during naps than narcolepsy patients.


Actigraphy

Actigraphy Actigraphy is a non-invasive method of monitoring human rest/activity cycles. A small actigraph unit, also called an actimetry sensor, is worn for a week or more to measure gross motor activity. The unit is usually in a wristwatch-like package wo ...
, which operates by analyzing the patient's limb movements, is used to record the sleep and wake cycles.Ancoli-Israel, S., Cole, R., Alessi, C., Chambers, M., Moorcroft, W., & Pollak, C. P. (2003). The role of actigraphy in the study of sleep and circadian rhythms. ''Sleep, 26''(3), 342–392. 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.Lichstein, K. L., Stone, K. C., Donaldson, J., Nau, S. D., Soeffing, J. P., Murray, D., … Aguillard, R. N. (2006). Actigraphy validation with insomnia. ''Sleep, 29''(2), 232–239. The advantage actigraphy shows over polysomnography is that it is possible to record for 24-hours a day for weeks. Furthermore, unlike the polysomnography, it is less expensive and non-invasive. An actigraphy over several days can show longer sleep periods, which are characteristic for idiopathic hypersomnia. 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.


The Stanford sleepiness scale (SSS)

The
Stanford sleepiness scale The Stanford Sleepiness Scale (SSS), developed by William C. Dement and colleagues in 1972, is a one-item self-report questionnaire measuring levels of sleepiness throughout the day. The scale, which can be administered in 1–2 minutes, is gener ...
(SSS) is a self-report scale that measures the different steps of sleepiness.Hoddes, E., Zarcone, V., Smythe, H., Phillips, R., & Dement, W. C. (1973). Quantification of Sleepiness: A New Approach. ''Psychophysiology, 10''(4), 431‑436. https://doi.org/10.1111/j.1469-8986.1973.tb00801.x 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. These results suggest that the SSS is a good tool to assess sleepiness in patients.


The Epworth sleepiness scale (ESS)

The 'Epworth sleepiness scale' (ESS) is also a self-reported questionnaire that measures the general level of sleepiness in a day Johns, Murray W. (1991). A new method for measuring daytime sleepiness: The Epworth sleepiness scale. ''Sleep, 14''(6), 540–545. 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. Because the causes of hypersomnia are unknown, it is only possible to treat symptoms and not directly the cause of this disorder. 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.
Modafinil Modafinil, sold under the brand name Provigil among others, is a central nervous system (CNS) stimulant medication used to treat sleepiness due to narcolepsy, shift work sleep disorder, and obstructive sleep apnea. While it has seen off-label ...
has been found to be the most effective drug against the excessive sleepiness, and has even been shown to be helpful in children with hypersomnia. 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.McWhirter, D., Bae, C., & Budur, K. (2007). The Assessment, Diagnosis, and Treatment of Excessive Sleepiness. ''Psychiatry (Edgmont), 4''(9), 26‑35. All other activities, such as eating or watching television, should be done elsewhere. For those patients, it is also important to go to bed only when they feel tired, than trying to fall asleep for hours. In that case, they probably should get out of bed and read or watch television until they get sleepy.


Epidemiology

Hypersomnia affects approximately 5% to 10% of the general population, "with a higher prevalence for men due to the sleep apnea syndromes".


See also

*
Encephalitis lethargica Encephalitis lethargica is an atypical form of encephalitis. Also known as "sleeping sickness" or "sleepy sickness" (distinct from tsetse fly-transmitted sleeping sickness), it was first described in 1917 by neurologist Constantin von Economo a ...
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Reticular formation The reticular formation is a set of interconnected nuclei that are located throughout the brainstem. It is not anatomically well defined, because it includes neurons located in different parts of the brain. The neurons of the reticular formation ...
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Sleep medicine Sleep medicine is a medical specialty or subspecialty devoted to the diagnosis and therapy of sleep disturbances and sleep disorder, disorders. From the middle of the 20th century, research has provided increasing knowledge and answered many ...
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Somnolence Somnolence (alternatively sleepiness or drowsiness) is a state of strong desire for sleep, or sleeping for unusually long periods (compare hypersomnia). It has distinct meanings and causes. It can refer to the usual state preceding falling asleep ...


References


External links


Help: I can't stay awake!
- Public Radio Interview with Dr. David Rye * - "Primary Hypersomnia" {{Bipolar disorder Sleep disorders