Movements during sleep are quite common, especially among children. They usually represent a generally benign and non-intimidating condition.
These are disorders disrupting sleep and have undesirable physical or verbal behaviours or experiences. They occur in association with sleep, in specific sleep stages or in the sleep-wake transition phases and are divided into Primary and Secondary under the terminology of Parasomnias.
The major Primary Parasomnias include Sleepwalking, REM Behaviour Disorder (RBD), Restless Legs Syndrome and Periodic Leg Movements, and Nightmare Disorder and Sleep Terror which are seen more in children.
These can sometimes be mistaken for seizures. The characteristic clinical features combined with EEG (Electroencephalogram) and PSG (Polysomnogram) recordings are essential to differentiate these conditions.
Sleepwalking is common in children between the ages of 5 and 12 but can persist into adulthood or, rarely, begin then. It usually starts abruptly within the first one-third of sleep and generally lasts less than 10 minutes. Sleepwalking episodes are usually uneventful; injuries and violent episodes are uncommon. Episodes can be precipitated by sleep deprivation, fatigue, other illnesses and sedatives/hypnotics.
General precautionary measures should be put in place when a person has been diagnosed with sleepwalking. The environment has to be made safe i.e. lock doors and windows, remove dangerous items and other hazards.
REM Behaviour Disorder (RBD)
RBD is an important REM sleep parasomnia commonly seen in elderly patients. The classic characteristic feature is the loss of muscle tone partially or completely during REM sleep. There is also the appearance of various abnormal motor activities during sleep. You may experience violent and dream-enacting behaviour during REM sleep. This can cause selfinjury or injury to your bed partner. RBD may be idiopathic or secondary and most cases are now thought to be secondary and associated with neurodegenerative disorders.
RBD has been linked to dopamine dysfunction based on PET scan findings. REM sleep without muscle atonia is the most important finding in the polysomnogram.
Treatment for REM Behaviour Disorder (RBD)
Treatment for RBD is usually initiated with clonazepam at bedtime and doses may have to be adjusted. It has been shown to be beneficial in the long-term. Drug discontinuation often results in prompt relapse. Other drugs such as tricyclic antidepressants and dopaminerelated medications have been tried but effects are unpredictable.
Restless Legs Syndrome (RLS)
RLS is the most common movement disorder. There is no diagnostic test for RLS. The diagnosis rests entirely on clinical features. RLS is a lifelong sensory-motor neurological disorder that often begins at a very young age but is mostly diagnosed in the middle or later years. It is more prevalent with increasing age and then plateaus for some unknown reason around age 85 to 90. In several surveys, it was found that it tends to be more prevalent in women. The disease is chronic and progressive. There are studies indicating that there is a possible genetic link.
The sensory manifestations of RLS include intense disagreeable feelings which are described as creeping, crawling, tingling, burning, aching, cramping, knife-like or itching sensations. These usually occur between the knees and ankles causing an intense urge to move the limbs to relieve these feelings.
Sometimes it can occur in the arms or other parts, especially in advanced stages. Most of the movements, especially in the early stages, are noted in the evenings when you are resting in bed. In severe cases, movements may be noted in the daytime when sitting or lying down.
Periodic Leg Movements (PLM)
At least 80% of RLS patients have Periodic Leg Movements (PLM) in sleep and sometimes in wakefulness (PLMW).
The condition affects sleep profoundly because there is not only a problem of initiation of sleep but maintaining sleep may also be difficult because of PLMs.
The causes of PLMs are uncertain. Most are idiopathic (have no apparent underlying cause) in nature but secondary causes like obstructive sleep apnoea, uremia, anaemia with iron deficiency, neuropathies, diabetes mellitus or certain drug withdrawals can also cause this. The causes of RLS are also uncertain.
The movements are repetitive in nature and can involve one or both limbs. It lasts about two seconds and occurs in the earlier or middle stages of sleep. It usually occurs in the legs and involves upward movement of the big toe and flexion of the ankle. It can sometimes be seen at the knee and hip. Both legs are usually involved and the same movements can also occur in the arms.
Not all patients with PLMs have RLS. PLMs cause excessive daytime sleepiness but RLS commonly causes insomnia.
Both RLS and PLMs generally undergo similar investigations including blood tests, nerve conductions, if necessary, and a polysomnogram.
Treatment for Restless Leg Syndrome (RLS) and Periodic Leg Movements (PLM)
If the cause is known, this should be treated. Caffeine, alcohol and nicotine should be avoided before sleep. Daily exercises and general physical therapies like hot and cold packs and massages can alleviate some of the symptoms.
Drugs that can aggravate these conditions should also be avoided, if possible. These include diphenhydramine, SSRIs, lithium and betablockers.
Symptomatic treatment includes the use of dopaminergic agents like levodopa, dopamine agonists like
pramipexole, pergolide, benzodiazepines like clonazepam, opioids and anticonvulsants like Gabapentin.
This is usually seen in children. The dreams are frightening and occurs in REM sleep and is associated with profuse sweating and arousal. The heart rate and respiratory rate are increased and the child remembers the dream.
Sleep Terror occurs during slow wave sleep and usually between the ages of five to seven years. There is a high incidence of family history of sleep terror. Episodes are characterised by extreme panic and sudden loud terrified screaming during sleep followed by physical activities. They can injure themselves. Recollection is partial or incomplete.
Though this has not been generally thought to be a movement disorder, it is generally discussed under this because of its clinical features. It is characterised by grinding or clenching of the teeth during sleep and associated with sleep arousals. Contraction of muscles associated with chewing leads to abnormal wear of the teeth, tooth pain, jaw muscle pain or temporal headache. There is usually no cause but can be associated with stressful situations or anxiety and seems to occur most frequently in highly motivated or vigilant individuals.
These are disorders of other organ systems that may manifest during sleep. Examples are seizures, respiratory disorders, cardiac arrhythmias and gastroesophageal reflux. A good history and physical examination and relevant investigations should help exclude these.