Parasomnias are abnormal behaviors that occur during sleep. They are usually caused by sudden abnormal awakenings (“arousals”) from critical stages of sleep. Parasomnias are usually mild and uncommon, but in some cases can be frequent and severe enough to warrant medical treatment. They occur when a person emerges suddenly from the deepest levels of sleep and ends up in a mixed state of both sleep and wake. The individual is awake enough to act out complex behaviors but still partially asleep and not completely aware of his/her surroundings.
One theory suggests that parasomnias are caused by abnormal electrical discharges coming from deep within the brain. This theory is supported by the observation that certain medications that treat the abnormal electrical discharges seen in seizures (epilepsy) are also effective in treating parasomnias.
It is generally very difficult to awaken someone to full alertness while they are in the middle of a parasomnia. Episodes are not associated with dreaming, and most people do not remember them. However if episodes are frequent, sleep disruption may be sufficient to cause daytime sleepiness.
Arousal-type parasomnias are common in young children, but much less common in adolescents and adults. They rarely imply psychological problems.
- run in families
- are more common and severe when a child is overly tired, has a fever, or is under stress
- occur in association with certain medications
The most common arousal-type parasomnias include:
- confusional arousals
- sleep walking
- sleep talking
- sleep terrors
- Most common in young children, but can be seen in adults
- Episodes often begin with sitting up in bed, crying, or thrashing around in bed
- Eyes usually remain closed
- Appears to be confused and upset
- Resists attempts to comfort or console
- Individual rarely leaves the bed
- Episodes can last up to 30 minutes, but usually more brief
- Seen in all age groups
- Behavior can be simple, such as getting out of bed and walking . More complex behaviors may occur (such as rearranging furniture, walking outdoors, driving a vehicle).
- Individual may sometimes speak, but speech is often unintelligible
- Injuries are uncommon, but can and do occur if individual engages in dangerous behavior such as walking
- outdoors in the winter, falling down stairs, etc)
- Some individuals may cook and eat a meal during sleep. This is an unusual variation of sleep walking.
- Sleep Talking
- Common in all age groups, vocalizations may be easily understood at times or may resemble mumbling or moaning.
- Shouting, screaming or singing are not uncommon.
- The most extreme and dramatic of the arousal parasomnias and the most distressing to witness
begins with a “blood-curdling” scream or shout
- Individual displays signs of extreme terror (eyes wide open, rapid breathing, extreme agitation, racing heart)
- May bolt out of bed and run chaotically around the room or house, or may run outside in an attempt to escape an imaginary threat
- May injure themselves or others in the course of the event
- As disturbing and frightening as these episodes may appear to an observer, the individual usually has no awareness of the event and has no memory of it afterward.
Other Parasomnias (non-arousal type)
REM Sleep Behavior Disorder
REM (rapid eye movement) sleep is the stage of sleep generally associated with dreaming. The role and need for REM sleep is poorly understood, but disorders of this sleep stage are common and can be disturbing. Under normal circumstances, all of the muscles in the body (except those used for breathing and eye movements) are paralyzed during REM sleep. All mammals experience REM sleep and the paralysis that is associated. There is probably some adaptive advantage to this paralysis, since movement during a dream might attract a predator in the middle of the night.
Disorders exist where the normal paralysis of REM sleep is absent. Under these circumstances an individual may acts out his/her dreams, sometimes violently. Injuries to self or others are common. People in REM sleep have been known to crash through a plate glass window, use a lethal weapon, or even strangle someone with their bare hands. Because dreams are often remembered, one can interview the individual afterward. They usually recount a threatening scenario or an attempt to protect self or family. Strangely, individuals in the middle of a REM episode often do not recognize family. Thus they may mistake them as a threat, attacking them and injuring them.
Also called “hypnic jerks”, sleep starts are sudden total body muscle jerks that occur during sleep onset. They usually occur as a single episode, but rarely they may occur many times during the night. Single episodes at sleep onset are completely benign. Multiple occurrences during the night suggest the possibility of epilepsy.
Bruxism (teeth grinding)
A common problem, bruxism can cause significant damage to otherwise health teeth. In addition, the noise associated with the grinding of teeth can be extremely annoying to a bed partner. Bruxism has been associated with sleep-related breathing problems such as Sleep Apnea.
Rhythmic Movement Disorders
May take one of several forms:
- head banging
- body rocking
- body rolling
The condition is seen most commonly in young children. These movements usually occur near sleep onset, but may occur throughout the night. Self-injury is uncommon but has been reported. These movement disorders are not generally associated with other medical or psychological disorders.