As a rule, people’s sleep cycles can be divided into several phases, namely five. The first four phases are characterized by various sleep wave patterns and the last phase is known as REM sleep. This phase occupies between 15 and 20% of the natural sleep cycle and is where most of the dreaming occurs, as well as muscle atony.

However, there are occasions when an alteration in this cycle occurs, such as in the case of REM sleep behavior disorder . Throughout this article we will discuss the characteristics of this condition, as well as its symptoms, causes and treatments that can alleviate the effects of this disorder.

What is REM sleep behavior disorder?

REM sleep behavior disorder was first described in 1986 by Dr. and researcher Carlos H. Schenck , a specialist in sleep disorders and behaviors. He defined it as a parasomnia of REM sleep; that is, a grouping of abnormal behaviours or phenomena that appear during this phase of sleep.

This type of sleep disorder, or parasomnia, is distinguished by affecting both the development of sleep and the person’s motor system . It causes the appearance of episodes of intense motor activity which affects various muscle groups.

These movements are manifested in the form of leg jerks, kicks, fist and arm strikes and even verbal manifestations such as shouting. These can be harmful to the person who accompanies you in your sleep.

The patient may even get out of bed , walk or stroll in response to the dream activity he or she is experiencing at that very moment. The violence of these motor activities is explained by the content of the dreams, which are often described as unpleasant, aggressive and virulent.

The incidence of this disorder among the population is really low, being reduced to only 0.5% of the population. However, on many occasions this is masked by other syndromes with similar clinical pictures . On a large number of occasions it is misdiagnosed as a nocturnal seizure disorder, consisting of a rare variety of obstructive sleep apneas syndrome.

Moreover, this disorder is much more frequent in men, representing 90% of CRT cases and appearing, usually, between 50 and 60 years of age.

What types are there?

REM sleep behavior disorder can manifest itself in two different categories: acutely, idiopathically or chronically .

The acute type of this disorder tends to be associated with periods of alcohol withdrawal. This is especially true for those with a history of years of alcohol abuse. Certain drugs or medications, such as sedative-hypnotics, anticholinergics, or fat-soluble blocking drugs, may also cause sleep disturbance.

Likewise, two more types of CRT have been identified. One of them consists of an idiopathic form of the disorder; that is, in which CRT consists of a disease in itself not associated with other alterations or lesions and which may evolve over time , becoming a form of neurodegenerative disease .

As for the chronic typology of CRT, it is caused by or forms part of the clinical picture of a series of neurodegenerative diseases such as Parkinson’s disease, dementia with Lewy bodies, multisystemic atrophy or, to a lesser extent, supranuclear paralysis, Alzheimer’s disease, corticobasal degeneration and spinocerebellar ataxias. Similarly, may be associated with disorders such as narcolepsy , brain stem lesions, tumour formations and strokes.

The symptomatology of this parasomnia

Within the clinical picture of sleep behavior disorder, we find a state of lack of muscular atony that manifests itself in the form of sudden and violent movements that appear at the beginning of the REM sleep phase and are maintained throughout it. These movements are an involuntary response to the content of the dreams experienced by the patient, who describes them as vivid, unpleasant and aggressive.

In most cases patients describe their dreams as an extremely unpleasant experience in which all kinds of fights, arguments, chases and even accidents or falls are depicted.

In a percentage of patients, specifically 25%, behavioural alterations during sleep prior to the appearance of the disorder have been determined. These behaviours include sleepwalking, screaming, twitching and convulsions of the limbs .

In the case of behavioral or motor symptoms typical of this disorder are found:

  • Talk.
  • Laugh.
  • Scream.
  • Cursing or insulting.
  • Gesticulations .
  • Agitation of the extremities.
  • Blows.
  • Kicks.
  • Jumping or jumping out of bed .
  • Running.

Due to the aggressiveness with which these behaviors appear, it is common for the patient to end up hurting or hitting the person next to him, as well as causing self-injury. Damage inflicted on both the companion and oneself includes lacerations, subdural haematomas and even fractures.

What is known about its causes?

The information obtained about the causes of REM sleep behavior disorder is quite scarce. In more than half of the cases, the cause of this condition is related to the future appearance of some type of neurodegenerative disease .

However, recent studies with animal models point to the possibility that there is a dysfunction in the brain structures of the pontine tegment, the locus coeruleus and the pedunculopontium nucleus; which are the main ones in charge of regulating muscle tone during sleep.

Is there a treatment?

Fortunately, there is a treatment for REM sleep behavior disorder based on the administration of daily doses of clonazepam . With a dose of between 0.5 and 1 mg, administered before sleep, and whenever indicated by the doctor, it is very likely that the person will experience greater control of sleep disturbances, including a decrease in the amount and intensity of aggressive behaviour and violent dreams.

In patients who do not respond to clonazepam or who have some type of contraindication, the use of melatonin, pramipexole or donepezil may be used to make the cases described as refractory.

In terms of disease prognosis, it is expected that with drug treatment, absolute remission of symptoms will be achieved. However, there is no definitive cure for CRT, so if the dose is lowered or the treatment is stopped the symptoms may reappear even more strongly .

It is necessary to specify that in those cases where CRT is caused by a neurodegenerative disease, treatment with clonazepam is not effective, and the patient must follow a specific treatment for the main disease.