Rem Sleep Disorder: Future Treatments And Prognosis

The outlook for REM sleep behaviour disorder (RBD) depends on several factors. Firstly, it depends on whether there is an underlying cause, such as narcolepsy or antidepressant use, or if it developed spontaneously. The severity of symptoms and the presence of treatment also play a role in the outlook, as does the existence of a neurodegenerative condition alongside RBD.

Treatment and medication

REM sleep behaviour disorder (RBD) is characterised by a loss of normal muscle atonia during REM sleep, which results in disruptive motor activity related to the acting out of dreams. Treatment is usually required as this can lead to injury to the patient or their bed partner.

Clonazepam

Clonazepam has been the first-line therapy for many years, with 2 large case series reporting efficacy with few side effects in the majority of patients. It is highly effective in relieving symptoms, with nearly 90% of patients experiencing relief within the first week, often on the first night. The initial dose is 0.5 mg at bedtime, with some persons requiring a rapid increase to 1 mg. However, long-acting hypnotics in the elderly or those with cognitive impairment can be associated with adverse events, especially unacceptable daytime sedation, confusion, and exacerbation of existing sleep apnea.

Melatonin

Melatonin is often used to treat sleep disorders and has been found to be effective in treating RBD. It has been found to reduce tonic REM activity in PSG and improve sleep efficiency. The effective dose of melatonin was 3–6 mg taken orally at bedtime. Only 36% of patients experienced adverse effects, which resolved with decreased dosing.

Zopiclone

Zopiclone was effective and well-tolerated in 8 out of 11 patients with side effects from clonazepam. It is a shorter-acting hypnotic that binds to the benzodiazepine receptor.

Levodopa/Carbidopa

Levodopa/carbidopa may be very effective in patients in whom RBD is a harbinger of Parkinson's disease. It comes in strengths of 25/100 mg, 25/250 mg, and 10/100 mg.

Other medications

Other medications that have been found to be effective in some patients with RBD include tricyclic antidepressants, sodium oxybate, desipramine, imipramine, fluvoxamine, paroxetine, trazodone, agomelatine, and vortioxetine.

Risk of injury

REM sleep behaviour disorder (RBD) is a parasomnia, a sleep disorder that involves abnormal and undesirable physical events or experiences that disrupt sleep. During RBD, people act out their dreams, often violently, while remaining asleep. This can cause injury to themselves or their bed partner.

The risk of injury is a key implication of RBD. The violent nature of the movements involved in RBD can put the individual and their bed partner at risk of physical injury. These injuries can be life-threatening, including head injuries and subdural hematomas. About 8 in 10 people with RBD experience sleep-related injuries. In addition, the bed partner of someone with RBD is also at risk of injury when sharing a bed with someone who unknowingly acts out their dreams.

Up to 90% of spouses of those with RBD report having sleep issues, and over 60% have experienced a physical injury. Even when the potential for physical injury is reduced, the disruption to sleep can be severe enough to cause relationship problems. However, nearly two-thirds of couples continue to sleep together despite the risk of disturbed sleep.

Sleep-related injuries reported among 30% to 81% of people with RBD include bruising, cuts, fractures, blunt trauma, and head trauma. Due to the risk of injury, it is important to seek treatment for RBD or, at the very least, create a safer sleeping environment.

Diagnosis

REM sleep behaviour disorder (RBD) is a parasomnia characterised by a loss of atonia of skeletal muscles during REM sleep, which results in people acting out their dreams. Diagnosis of RBD is important to predict neurodegenerative diseases, as there is a strong association between RBD and diseases caused by the deposition of alpha-synuclein in neurons (synucleinopathies), such as Parkinson's disease, Lewy body dementia, and multiple system atrophy.

The diagnostic assessment of RBD should begin with a detailed clinical history, including a discussion with the patient and their bed partner or roommate. Any recorded videos of the patient sleeping should also be examined.

Polysomnography (PSG) is then necessary to verify the loss of sleep atonia and to document behaviours during sleep. PSG can also help rule out conditions that may mimic RBD, such as obstructive sleep apnea, non-REM sleep parasomnias, nocturnal epileptic seizures, periodic limb movements, and psychiatric disorders.

The American Academy of Sleep Medicine's International Classification of Sleep Disorders states that, to receive a diagnosis of RBD, a person must meet four criteria:

• They must have repeatedly experienced episodes of acting out their dreams with vocalisations or arm and leg movements that correspond to what is taking place in their dream.
• Episodes must occur during REM sleep, as confirmed by an in-laboratory polysomnogram or clinical history.
• Episodes must include sleep without atonia, as confirmed by polysomnography.
• The episodes must not be attributed to something else, such as another sleep or mental health disorder, medication side effects, or substance abuse.

If RBD is suspected, a doctor may refer the patient to a sleep physician, who will conduct a physical and neurological exam to rule out other potential causes, such as alcohol, medications, or narcolepsy. The sleep physician will also look for symptoms of Parkinson's disease, such as hand tremors or muscle stiffness.

The patient may then be referred to a sleep lab for a polysomnogram, an overnight sleep study. During the study, sensors monitor the patient's breathing, eye movements, arm and leg movements, brain and heart activity, and blood oxygen levels. The exam is often videotaped to record any dream enactment behaviour.

After the exam, a sleep physician will review the patient's medical history, symptoms, and the results of their polysomnogram to determine whether a diagnosis of RBD is appropriate.

Causes

REM sleep behaviour disorder (RBD) is a parasomnia, a sleep disorder in which people act out their dreams, often in violent ways. The exact cause of RBD is unclear, but there are several factors that are associated with the condition.

RBD is most common in men over 50, with an average age of onset at 61 years. It is rare in women and children. In most cases, there is nothing that can be done to prevent RBD, as it is associated with risk factors that are unchangeable, such as age and the presence of narcolepsy or a neurodegenerative condition.

RBD is strongly associated with certain neurodegenerative disorders. About 97% of people with isolated (idiopathic) RBD will develop Parkinson's disease, Lewy body dementia, or multiple system atrophy (MSA) within 14 years of diagnosis. These conditions are called alpha-synucleinopathies.

The development of RBD can also be symptomatic (secondary) due to an underlying cause, such as Type 1 narcolepsy. When a person has both an alpha-synucleinopathy and RBD, it is considered secondary RBD.

Certain antidepressants can also cause RBD. This is known as drug-induced RBD and is thought to be caused by imbalances in dopamine and serotonin (neurotransmitters) involved in REM sleep.

Other factors that can increase the intensity of REM sleep and cause RBD include brainstem brain tumours and sleep deprivation. Episodes of RBD may also be triggered by the use of certain medications, other sleep disorders, and alcohol consumption.

Treatment

The treatment for RBD involves a combination of lifestyle changes, medication, and injury prevention techniques. Lifestyle changes include reducing or eliminating the use of alcohol and certain prescription drugs. Medication such as melatonin and clonazepam can also help to reduce symptoms.

Symptoms

REM sleep behaviour disorder (RBD) is a parasomnia, a sleep disorder in which people act out their dreams, often violently. The symptoms of RBD can vary in severity, but they can include:

• Mild muscle twitches or limb movements
• Vocalisations, such as talking, shouting, or screaming
• More pronounced body movements, such as punching, kicking, grabbing, jumping or falling out of bed
• Self-injury or injury to a bed partner

People with RBD are rarely aware of their behaviours during sleep and often only find out when they are informed by a bed partner or roommate, or when they wake up with an injury. Episodes can occur once or multiple times during the night, or even just once in a while, and they tend to worsen over time.

RBD is often confused with sleepwalking and sleep terrors, but there are some key differences. People with RBD can usually be woken up easily and are typically alert and able to recall details of their dreams upon waking. In contrast, those with sleepwalking or sleep terrors tend to be confused upon waking and do not recall their dreams.

Frequently asked questions