LONG SLEEPER

A long sleeper is an individual who consistently sleeps substantially more in 24 hours than does the typical person of his or her age group. Sleep, although long, is basically normal in architecture and physiology.

A consistent daily pattern, documented by a carefully kept sleep log, showing 10 to 12 hours of sleep per night over a minimum of seven days is essential to the diagnosis of long sleeper. In general, the long sleeper’s decision to consult a sleep clinician has little to do with sleep symptoms, but, rather, the complaint usually focuses on the curtailment of the awake period by the apparent increased need for sleep. Individuals who are long sleepers have normal sleep efficiency and timing of sleep. In uncomplicated cases, there are no complaints about quality of sleep, daytime sleepiness, or difficulties with waking mood, motivation, or performance as long as sufficient sleep is obtained routinely to fulfill the apparently increased sleep “need.” Onset is typically in childhood.

Many long sleepers because of occupational or educational demands, function with reasonable success on nine hours of sleep per night during the work or school week, with increases to 12 to 15 hours per 24 hours on weekends and holidays. Long sleepers obtaining less than this amount of sleep have daytime symptoms of insufficient sleep.

SHORT SLEEPER

A short sleeper is a person with a routine pattern of obtaining five hours or less of sleep per 24 hours, without incurring any reduction or impairment in daytime functioning.

Sleep requirements fall on a continuum and are normally distributed in the general population. Whereas most normal adults without sleep complaints typically require and obtain seven to eight hours of sleep per 24 hours, some individuals typically require much less sleep without experiencing subjective or objective daytime somnolence. Despite its unusually short length, the usual sleep period of the short sleeper is typically unbroken and results in a sense of being refreshed upon awakening. The limited amount of sleep occurs spontaneously, not as a result of volitional attempts to restrict sleep or as a function of avoiding sleep. The sleep obtained is fairly stable in amount from night to night. There are no weekend or holiday reversions to extended periods of sleep. Moreover, short sleepers do not report decreased mood, irritability, or performance deficits during their periods of wakefulness. In young and middle-aged adults, an average of five hours of sleep or less per night could reasonably be considered a short sleep pattern. If naps occur, they need to be added to the nocturnal sleep time (e.g., an elderly person sleeping four hours per night with a two-hour afternoon nap is not a short sleeper).

SNORING

Snoring is a respiratory sound generated in the upper airway during sleep that typically occurs during inspiration but may also occur in expiration; the snoring described here occurs without episodes of apnea or hypoventilation. The intensity of snoring may vary and often will disturb the bed partner’s sleep and even awaken the patient. Snoring in this context does not cause symptoms of daytime sleepiness or insomnia in the patient.

SLEEP TALKING

The essential feature is talking, with varying degrees of comprehensibility, during sleep.

SLEEP STARTS (HYPNIC JERKS)

Sleep starts, also known as hypnic jerks, are sudden, brief, simultaneous contractions of the body or one or more body segments occurring at sleep onset. Sleep starts (hypnic jerks) usually consist of a single contraction that often affects the body asymmetrically. The jerks may be either spontaneous or induced by stimuli. Sleep starts are sometimes associated with the subjective impression of falling, a sensory flash, or a visual hypnagogic dream or hallucination. A sharp cry may occur. The patient may not recall a jerk that was noted by a bed partner if the sleep starts do not cause awakening. Multiple jerks occasionally occur in succession.

BENIGN SLEEP MYOCLONUS OF INFANCY

Benign sleep myoclonus of infancy (BSMI) is characterized by repetitive myoclonic jerks that occur during sleep in infants. BSMI is an apparently rare phenomenon seen in the first year of life. Unlike the jerks of myoclonic seizures and myoclonic encephalopathy, the jerks of BSMI occur exclusively during sleep. The jerks are often bilateral and massive, typically involving large muscle groups. The movements can occur in the whole body, the trunk, or only the limbs.

HYPNAGOGIC FOOT TREMOR AND ALTERNATING LEG MUSCLE ACTIVATION

Hypnagogic foot tremor (HFT) is rhythmic movement of the feet or toes that occurs at the transition between wake and sleep or during light NREM sleep (stages 1 and 2). Alternating leg muscle activation (ALMA) consists of brief activation of the anterior tibialis in one leg in alternation with similar activation in the other leg during sleep or arousals from sleep. HFT may be a relatively common and normal finding. Affected individuals move the feet or the toes rhythmically for seconds to minutes during drowsy wakefulness or lighter stages of sleep. It can be pathologically exaggerated in occasional patients. ALMA is a polysomnographic pattern with unknown physical or clinical manifestations, but frequency of muscle activations, length of activations, and occurrence primarily with arousals suggest that ALMA may be similar to HFT or represent an EMG manifestation of some episodes of HFT. The two phenomena are considered together because the relationship between them remains to be clarified and the similarity in a number of their features suggests they may not be fully independent entities.

PROPRIOSPINAL MYOCLONUS AT SLEEP ONSET

Propriospinal myoclonus at sleep onset (PSM) consists of sudden muscular jerks occurring in the transition from wakefulness to sleep and, rarely, during intrasleep wakefulness and upon awakening in the morning. The jerks involve mainly axial muscles according to propriospinal propagation. The jerks may be of variable intensity; they are isolated, recurring in quasi-periodic fashion for variable durations, or may be repeated in brief clusters of a few movements, separated by longer intervals. Jerks involve the abdominal and truncal muscles first and are then propagated to proximal muscles of the limbs and the neck. The pattern of movement is usually flexor but may be an extension of the trunk. Vocalization rarely occurs. The jerks are most often spontaneous, but exceptional cases in which jerks could be evoked by external stimulations have been reported. The jerks appear to be related to a state of relaxed wakefulness, being present when the patient tries to fall asleep. Any mental activation makes the jerks disappear. The jerks eventually disappear at sleep onset and remain absent throughout all stages of sleep.

EXCESSIVE FRAGMENTARY MYOCLONUS

Excessive fragmentary myoclonus is characterized by small movements of the fingers, toes, or corners of the mouth or small muscle twitches resembling fasciculations that do not cause gross movement across a joint space. These movements can occur in wakefulness or sleep, and the patient is typically unaware of their occurrence. In many cases, the movements are documented as an incidental EMG finding on polysomnography. Daytime sleepiness or fatigue may be present, or patients may be totally asymptomatic. When minor movement across a joint space is present, the movement resembles the small twitch-like movements of the fingers, toes, and the corner of the mouth intermittently seen in REM sleep. The potentials persist irregularly for periods of time ranging from hours to the entire sleep period. Unlike the similar movements noted in REM sleep, they do not occur in brief isolated clusters. Instead, the movements are relatively evenly spaced throughout the polysomnographic recording. There are typically large numbers of the EMG potentials of excessive fragmentary myoclonus in a single sleep record. The EMG potentials are very brief (75 to 150 milliseconds). The muscle activity occurs in both NREM and REM sleep. The causative relationship between excessive fragmentary myoclonus and daytime sleepiness, however, is often difficult to establish, as many patients have other disorders of sleep.

OTHER PHYSIOLOGICAL (ORGANIC) SLEEP DISORDER

A sleep disorder is temporarily classified here if it cannot currently be placed elsewhere in the ICSD-2 and the expectation is that a final diagnosis will have a physiological or medical basis. This diagnosis is also used as a permanent classification for sleep disorders that cannot be placed anywhere else in the ICSD-2, but are believed to be due to physiological or medical factors. This is also the default category in which to place sleep disorders not classifiable elsewhere, when there is no evidence whether the sleep disorder has a medical, a substance, or a psychiatric etiology.

OTHER SLEEP DISORDER NOT DUE TO SUBSTANCE OR KNOWN PHYSIOLOGICAL CONDITION

A sleep disorder is classified here if it cannot be placed anywhere else in the ICSD-2 and a suggestion exists that it is based on psychiatric or behavioral factors.

ENVIRONMENTAL SLEEP DISORDER

Environmental sleep disorder is a sleep disturbance due to a disturbing environmental factor that causes a complaint of either insomnia or daytime fatigue and somnolence.

FATAL FAMILIAL INSOMNIA

Fatal familial insomnia is a progressive disorder characterized by initial difficulties in falling asleep and maintaining sleep, spontaneous lapses from quiet wakefulness into a sleep state with enacted dreams (oneiric stupor), and loss of slow-wave sleep features.

Autonomic hyperactivity, with pyrexia, salivation, hyperhydrosis, tachycardia, tachypnea and dyspnea, is present. The disorder includes somatomotor disturbances, with dysarthria, dysphagia, tremor, spontaneous and reflex myoclonus, dystonic posturing, and a positive Babinski sign. The disorder may progress to unarousable coma and finally death. Cognitive function is retained until impaired alertness makes testing impossible.

FIBROMYALGIA

According to the 1990 American College of Rheumatology consensus criteria, fibromyalgia is characterized by widespread pain of at least three months duration and muscle tenderness, as determined by palpation.

SLEEP RELATED EPILEPSY

A seizure is a paroxysmal event resulting from a sudden excessive discharge of the neurons of the cerebral cortex, whereas epilepsy is a condition of recurrent unprovoked seizures. Sleep facilitates epileptic activity and seizures. Some types of epileptic syndromes have a marked tendency to manifest only or predominantly during sleep, e.g., nocturnal frontal lobe epilepsy (NFLE), benign epilepsy of childhood with centrotemporal spikes (BECT), early-onset or late-onset childhood occipital epilepsy, juvenile myoclonic epilepsy (JME), generalized tonic-clonic seizures on awakening, a subgroup of temporal lobe epilepsy, tonic seizure (as a component of Lennox-Gastaut syndrome), Landau-Kleffner syndrome, and continuous spike waves during NREM sleep (CSWS).

• NFLE may present in 4 distinct ways: (1) NFLE may mimic a disorder of partial arousal with sleep walking, confusional arousals, or sleep terrors. NFLE may present as (2) nocturnal paroxysmal dystonia; (3) repetitive stereotypic behavior; or (4) nocturnal paroxysmal arousals. Ictal and interictal EEG’s are often normal since the focus for the epileptic discharge may be deep in the brain.

• BECT can present with focal clonic facial twitchings which are often preceded by perioral numbness. These seizures are more often seen in drowsiness and sleep than wakefulness. The clinical course is often benign with disappearance of the seizures in adulthood.

• JME is characterized by massive bilaterally synchronous myoclonic jerks which are most frequently noted on awakening.

• CSWS (formerly known as electrical status epilepticus of sleep [ESES]) is characterized by continuous and diffuse slow spike-and-wave complexes persisting through NREM sleep (at least 85% of the duration), as well as neuropsychological and motor impairment. Despite the continuous presence of epileptic spike-wave activity on EEG in sleep, there may be no associated visible sleep related movement. However, clinical epileptic seizures are sometimes seen in the daytime.

SLEEP RELATED HEADACHES

Sleep related headaches are a group of unilateral or bilateral headaches of varying severity and duration that occur during sleep or upon awakening from sleep. It is a heterogeneous group of different headache entities with the common feature of occurrence during sleep or upon awakening. Most sleep related headaches are daytime headache conditions that also occur during sleep, including migraine, cluster headache, and chronic paroxysmal hemicrania. There are other headaches that occur solely with sleep, for example, hypnic headaches. Finally medical, neurologic, psychiatric, and sleep disorders can cause sleep related headaches.

#flusheft Migraines are common episodic headaches of moderate to severe intensity that last between four and 72 hours. Nausea, emesis, photophobia, phonophobia, and unilateral and throbbing pain are common associated features. They may occur during the day or during sleep; approximately 50% of migraine attacks occur between 4:00 a.m. and 9:00 a.m. Migraine headaches do not have a fixed association with a particular sleep stage. The patient may awaken with a migraine out of REM sleep, or the headaches may occur in relationship to stage 3 and 4 NREM sleep.

Cluster headaches are severe, unilateral, periorbital or temporal headaches that start quickly and peak within 10 to 15 minutes. They have a relatively shorter duration, usually lasting 15 minutes to three hours (mean, 60 minutes). The headaches occur daily during cluster periods—usually one to three attacks per day over a period of one to two months. Most patients have one cluster period per year, though this can vary from patient to patient. The headaches tend to occur at the same hour each day. One or more cranial autonomic features (i.e., conjunctival injection, lacrimation, nasal congestion, rhinorrhea, forehead and facial sweating, miosis, ptosis, or eyelid edema) invariably accompany attacks of cluster headaches. A strong predilection for attacks to occur during sleep is well recognized, and these attacks are strongly related to REM sleep.

Chronic paroxysmal hemicrania closely resembles cluster headaches and consists of severe unilateral orbital, supraorbital, or temporal pain associated with one or more cranial autonomic features. However, the attacks are usually of shorter duration (lasting two to 45 minutes) and occur more frequently within a 24-hour period. In contrast to cluster headaches, chronic paroxysmal hemicrania is exquisitely sensitive to indomethacin. Attacks are also strongly associated with REM sleep.

Hypnic headaches are an uncommon type of headache that awakens the patient from sleep with a generalized or lateralized headache that usually lasts five to 60 minutes (range 10 to 180 minutes), with a frequency of at least 15 times per month for at least one month. In comparison to cluster headaches, hypnic headaches are less severe, often bilateral, and not associated with cranial autonomic features. They may occur one to three times during the night, with many patients reporting that the headaches occur at the same time of the night. These headaches tend to occur during REM sleep. However, they have also been reported to occur during stage 3 NREM sleep. A positive therapeutic response to lithium, indomethacin, and caffeine has been reported in many patients.

Other medical (e.g., hypertension), neurologic (e.g., brain tumors, arteriovenous malformations, and trauma), psychiatric (e.g., depression), and sleep disorders (e.g., snoring and OSA) can also give rise to headaches that may occur during sleep or upon awakening from sleep.

SLEEP RELATED GASTROESOPHAGEAL REFLUX

Sleep related gastroesophageal reflux is characterized by regurgitation of stomach contents into the esophagus during sleep. This is a disorder in which the patient can awaken from sleep with a sour taste in the mouth or a burning discomfort or pain in the substernal area. This is generally described by the patient as heartburn. The pain is usually substernal, although it can be described as pain in the epigastrum or in the throat area. The pain appears to be caused by the retrograde flow of gastric contents, generally acidic, that irritates the esophageal mucosa, resulting in the pain or discomfort associated with heartburn. Awakenings from sleep associated with this discomfort can lead to a complaint of disrupted sleep or insomnia. Gastroesophageal reflux can be asymptomatic.

SLEEP RELATED CORONARY ARTERY ISCHEMIA

Sleep related coronary artery ischemia is characterized by ischemia of the myocardium that occurs at night, presumably during sleep. The symptoms of sleep related coronary artery ischemia are very similar to those that characterize episodes of cardiac ischemia during the daytime. Classically, there is a feeling of chest pressure or pain that wakes the patient from sleep and is described as a “viselike” discomfort. The discomfort may radiate to the chin and jaw and to the arm, especially the left arm. Electrocardiographic monitoring during sleep reveals horizontal or down-sloping ST segment depression of greater than or equal to 1 mm or ST segment elevation of 1 mm or more. The electrocardiographic evidence of sleep related coronary artery ischemia is sometimes unaccompanied by chest discomfort or other symptoms (silent ischemia) and may be incidentally noted either on Holter monitoring or telemetry.

SLEEP RELATED ABNORMAL SWALLOWING, CHOKING, AND LARYNGOSPASM

Sleep related abnormal swallowing is a disorder in which dysfunction of muscles associated with deglutition lead to pooling of saliva in the upper airway, causing coughing, choking, and arousal from sleep. Patients may report choking and difficulty breathing during the night. Polysomnographic recordings do not demonstrate OSA, only repetitive short-lived episodes of coughing or gagging. These episodes may occur after periods of “gurgling,” which are likely due to saliva accumulation in the hypopharynx and aspiration into the trachea. Episodes halt quickly after arousal. Sleep may be fragmented and restless. Attacks may be associated with an acute fear of suffocation or more generalized anxiety. Whether abnormal swallowing is also present in these patients during wakefulness is unknown. However, if underlying disorders affecting deglutition or salivation are present, patients may have abnormal swallowing function while awake.

Sleep related choking is a disorder of unknown etiology characterized by frequent episodes of awakening with a choking sensation. Patients report sudden repeated awakening during the night with a choking sensation and an inability to breathe. Episodes are associated with fear and anxiety. There is no evidence of stridor or witnessed abnormalities of breathing during the night by the bed partner.

Sleep related laryngospasm is a disorder in which tracheal muscle dysfunction or paratracheal soft-tissue swelling causes stridor or interruption of airflow, with associated arousal from sleep. Patients may have total or near-total cessation of airflow while asleep and suddenly arouse. This brief respiratory blockage (lasting an estimated five to 45 seconds) is often followed by a period of stridor lasting several minutes, which evolves to normal breathing. Episodes are associated with panic and fear of suffocation; cyanosis may be observed. In some cases of laryngospasm during sleep, patients may have frequent laryngeal stridor (which may be difficult for families to differentiate from snoring), associated tachypnea, and intermittent upper-airway blockage.

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Source: American Academy of Sleep Medicine, International Classification of Sleep Disorders, 2nd ed.: Diagnostic and Coding Manual, Westchester, Illinois: American Academy of Sleep Medicine, 2005.