The Stanford Center for Sleep Sciences and Medicine

Nighttime Sleep Behaviors

Sleep disorders involving abnormal behaviors during sleep are called Parasomnias.

These nighttime activities can occur at any age.

The Stanford Sleep Medicine Center has extensive experience diagnosing and treating these unique sleep problems.

There are several different types of parasomnias, learn more by clicking the links below.

Sleep Walking/Talking

Sleepwalking, also known as Somnambulism, is a condition in which a sleeping person exhibits behaviors associated with being awake, appears to be awake but is actually still sleeping. Sleep talking is when an individual vocalizes in their sleep, anything from a few words to whole conversations. These episodes usually occur during non-REM, delta (“slow wave”) sleep, during which the arousal threshold is particularly high. The sleeper often has little or no memory of the event. Sleep disturbances experienced during slow wave sleep may precipitate a sleep-walking episode; these typically occur in the first half of the night.

Sleepwalking or talking episodes usually involve routine activities which can range from the mundane – sitting up in bed or walking to the bathroom – to the extreme, including getting in a car and driving. Sleep-related eating and other complex activities may be completed, to the surprise of the individual the following morning. Sleep walkers are very rarely aggressive, but may become confused and combative when attempts are made to arouse them.

While sleepwalking can occur at any age, it is most common in children, and tends to run in some families. Often, sleepwalking diminishes as children grow older. Conditions such as fatigue, stress or anxiety, lack of sleep, illness, physiological stimuli such as a full bladder, or alcohol use are often associated with sleepwalking episodes.

In many cases, people who sleepwalk don’t need extensive examinations or testing. However, in patients for whom episodes are regular, persistent, or involve alarming behavior, our specialists will perform tests to rule out certain triggers, such as sleep disordered breathing, or other types of nocturnal behavior such as nocturnal seizure disorder.

Importantly, for habitual sleepwalkers, the sleeping environment should be modified to reduce the risk of injury. This includes ensuring that all doors and windows are locked, sharp objects are put away and secured, and the risk of tripping and falling, especially down stairs, is minimized. In certain cases, after an appropriate evaluation, sleepwalking may be treated with low doses of certain medications.

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Sleep Terrors

Also called “night terrors”, these episodes are characterized by extreme terror and a temporary inability to attain full consciousness. The person may abruptly exhibit behaviors of fear, panic, confusion, or an apparent desire to escape. There is no response to soothing from others. They may experience gasping, moaning or screaming. However, the person is not fully awake, and once the episode passes, often returns to normal sleep without ever fully waking up. In most cases, there is no recollection of the episode in the morning.

Like sleepwalking, night terror episodes usually occur during NREM delta (slow wave) sleep. They are most likely to occur during the first part of the night. The timing of the events helps differentiate the episodes from nightmares, which occur during the last third of the sleep period.

While sleep terrors are more common in children, they can occur at any age. Research has shown that a predisposition to night terrors may be hereditary. Emotional stress during the day, fatigue or an irregular routine are thought to trigger episodes. Ensuring a child has the proper amount of sleep, as well as addressing any daytime stresses, will help reduce terrors.

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Confusional Arousals

A confusional arousal is when a sleeping person appears to wake up but their behavior is unusual or strange. The individual may be disoriented, unresponsive, have slow speech or confused thinking. Confusional arousals typically occur in the first 2 hours of falling asleep during a transition from “deep” sleep to a lighter stage of sleep. The episode may last only a few minutes or continue on for a longer period of time. There is usually little or no recall of the arousal or any event that may had occurred during the episode the next morning.

Confusional arousals can occur at any age, but are more common in children. Sleep disruptions caused by health problems (such as fever), travel, abrupt sleep loss, migraine, and irregular sleep-wake schedules may trigger an episode. Another sleep disorder such as sleep-disordered-breathing and to a lesser extent restless legs syndrome or nocturnal asthma may also be seen in association with the confusional arousals.

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REM Behavior Disorder

Dreaming occurs during Rapid Eye Movement or REM sleep. With REM sleep, changes occur in brain signaling which cause reduced muscle tone in many of the body’s muscles; this may be called REM sleep muscle paralysis or muscle atonia. This is considered a normal function of REM sleep. REM Behavior Disorder occurs when the body maintains relatively increased muscle tone during REM sleep, allowing the sleeper to move and act out their dreams. Movements may be as minor as leg twitches, but can result in very complex behavior that may cause serious injury to the individual or the bed partner. REM sleep behavior disorder is characterized by abnormal behaviors during REM sleep that may cause sleep disruption or injury; these are often manifestations of action-filled or violent dreams. Behaviors may include twitching, utterances, flailing, kicking, sitting up, and leaving the bed. At the end of an episode, an individual may awaken and become quickly alert; they may be able to provide a coherent dream story.

Adverse reactions to certain drugs or drug withdrawal can sometimes appear as RBD. However, the disorder is more common with age, and has been associated with certain neurological disorders in some cases.

The diagnosis of REM Behavior Disorder may be suggested by a careful evaluation but should be confirmed by a sleep study, to evaluate for other sleep disorders and to confirm abnormal muscle tone during REM sleep. In terms of management, precautions to ensure the safety of the individual and others in the sleep environment are key. Treating coexisting sleep disorders is important, and medications are often changed or started to reduce symptoms of this disorder.

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Sleep Paralysis

Sleep Paralysis is a normal part of the REM sleep. However, it is considered to be a disorder when it occurs outside of REM sleep. It can occur in otherwise healthy people, as well as in those presenting symptoms of narcolepsy, cataplexy and hypnagogic hallucinations. When it occurs without narcolepsy, it is classified at Isolated Sleep Paralysis (ISP).

As discussed in the REM Behavior Disorder section, muscle atonia, or sleep paralysis most commonly occurs when a person is either falling asleep awakening. If an individual has awareness as the body enters or exits REM sleep, they may experience sleep paralysis. Sleep paralysis can last from several seconds to several minutes; episodes of longer duration are typically disconcerting and may even provoke a panic response. The paralysis may be accompanied by rather vivid hallucinations, which most people will attribute to being parts of dreams.

Sleep paralysis can occur in otherwise normal sleepers, and is surprisingly common in its occurrence and universality. It has also been linked to certain conditions such as increased stress, excessive alcohol consumption, sleep deprivation, and narcolepsy.

Treatment of Sleep Paralysis is often limited to education about sleep phases and atonia that normally occurs as people sleep. If episodes persist, the sleep specialist may evaluate for narcolepsy, which is commonly present in those suffering from sleep paralysis.

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Nightmares

Nightmares are vivid dreams that contain frightening images or cause negative feelings such as fear, terror, and/or extreme anxiety. If awakened from REM sleep during a nightmare, the sleeper can usually provide a detailed description of the dream content. The nightmare can cause the sufferer to awaken in a heightened state of distress, resulting in perspiration and an elevated heart rate. Often it takes time to recover from the negative emotions invoked by the nightmare and the person may have difficulty returning to sleep.

Nightmares may be able to be distinguished from sleep terrors based on the timing of the episode and the whether dream content can be recalled. Nightmares are more likely to occur during the last third of the night when there is a higher concentration of REM sleep.

Nightmares have been known to have both psychological and physical causes. Factors including illness, anxiety, or even sleeping in an uncomfortable position can lead to bad dreams. Post traumatic stress disorder can trigger frequent nightmares, as can side effects from various medications and narcotics such as amphetamines and cocaine.

There are a number of methods, both medical and non-medical, to alleviate the conditions that often cause chronic nightmares. Often, alleviating the stresses in the home or personal life will reduce anxiety at bedtime that can trigger nightmares. Regular exercise, yoga and meditation may also help reduce stress and improve sleep quality.

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