It is normal to move around during sleep to a certain extent but in some people abnormal movements and complex patterns of behaviour may occur. These are sometimes known generally by the medical term of Parasomnia, but the range of unusual events that occur during sleep is so wide that it is important to accurately pinpoint the type of events occurring in each patient.

The type of movements, whether they are linked to dreams or other sensations, how much recollection the subject has of the events, the time of night when they occur and any link to any trigger factors such as sleep deprivation, alcohol or drugs may all be important in working out the cause of the problem. It may also be necessary to come into hospital for a polysomnography to see exactly what is going on. 


Sleepwalking is one of the most common types of movement during sleep. It is present in around 10% of children, particularly between the ages of 4-8, but may continue throughout life. It is due to incomplete awakening from the deepest stages of Non-Rapid Eye Movement (NREM or non-dream) sleep so that there are some features of being asleep and some of being awake.

A sleepwalker often walks around the room or may go out of the house but only partially responds to other people. The subject may be guided back to bed but any attempt to restrain or waken a sleepwalker should be avoided since this may lead to sudden violence.
Sleepwalking may be due to lack of sleep, stress, sedative drugs or alcohol.

Treatment is geared to relieving these problems and ensuring that the environment of the sleeper is safe.

Not everyone who walks in their sleep has what is known medically as sleepwalking. The common conditions which can lead to people walking in their sleep are:

  • Sleepwalking
  • Sleep terrors
  • Nocturnal epilepsy
  • REM sleep behaviour disorder
  • Confusional arousal


Sleep terrors, sleep talking, sleep eating, sleep-related sexual activity

These conditions all usually have a similar basis to sleepwalking and may be due to the same trigger factors.


Nocturnal epilepsy

Most epileptic seizures occur during the day but there are some specific types of epilepsy which occur particularly at night. The most important is frontal lobe epilepsy which arises from a small abnormality at the front of the brain. This is often invisible on testing such as MRI or CT scans but may cause episodes in which the subject utters a scream or a screech and then makes frenetic movements and may walk out of the bed. The episode subsides rapidly and the subject is usually only aware of a sensation of fear, for instance as if escaping from a near-death experience. Treatment with anticonvulsant drugs is usually effective.


REM sleep behaviour disorder

In this condition there is a combination of vivid dreams with an aggressive content, associated with often violent physical movements related to the content of the dream or nightmares, due to an abnormality in the formation of REM (dream) sleep.

This condition is usually seen in males over the age of 50 but can be induced by drugs or alcohol in younger people. The characteristic feature is that the subject feels that he or she is being attacked or chased or is attacking or chasing someone or something else. The dreams are frightening and the subject responds aggressively, although in its early stages there may only be kicking movements associated with swearing. Many people who develop the REM sleep behaviour disorder subsequently show features of Parkinson’s disease.
The diagnosis can be confirmed by polysomnography. Treatment with specific types of hypnotics is usually effective. Drugs such as Melatonin and Gabapentin may also be useful.


Sleep starts (hypnic jerks)

Sleep starts are normal and extremely common. They happen just as you are falling asleep and are often associated with a sensation of falling or occasionally with a loud noise or flash of light. Either the whole body or just the legs are felt to jerk. They may be worsened by sleep deprivation, stress or caffeine-containing drinks.


Restless Legs Syndrome (RLS)


Sleep paralysis

Sleep paralysis is the inability to move the body before falling asleep or just after waking up. Almost half the population have experienced this occasionally. It is particularly common around the age of 20 and after the age of 60. It is often frightening, particularly if there is a sensation of not being able to breath. If it occurs frequently it may be part of a sleep disorder such as narcolepsy and requires further investigation.

Case Study

IES, aged 21

IES saw his GP because his partner had been frightened by his behaviour at night. She had noticed that about an hour after falling asleep he would say a few words, get out of bed, dress, go downstairs and sometimes put the cooker on. On one occasion he had opened the front door and walked 200 metres down the road before she had caught up with him. She had found him trying to open the window of their bedroom and unable to undo the catch. She had also been woken once by him falling down the stairs and when she had got to him he had looked dazed but went back to bed without any difficulty. She noticed that these episodes were worse on Friday and Saturday nights and when they slept away from home.

He had never had any other medical problems in the past. He did not take any tablets or medicines but he remembered that his mother had told him that he had not slept well when he was younger and had often been found wandering around his parents’ bedroom. He had been under stress at work over the previous nine months because of bullying but felt that he had been coping with this alright.

He was referred to a sleep specialist and underwent polysomnography. This showed that he woke suddenly from the deeper stages of NREM sleep and appeared confused. No other abnormalities were found.
A diagnosis of sleepwalking was made. He was advised to obtain more sleep each night during the working week, to drink less alcohol on Fridays and Saturdays and to address the bullying problem at work. He was given medication to take when he slept away from his home. The episodes subsided over two months and have not returned.