Understanding Rem Sleep Behavior Disorder And Its Diagnosis

REM sleep behaviour disorder (RBD) is a parasomnia involving dream enactment behaviour associated with a loss of muscle tone during rapid eye movement (REM) sleep. This allows people to act out their dreams, which are often vivid, intense, and violent. RBD is usually observed in middle-aged to elderly people, and more often in men.

The exact cause of RBD is unknown, but it may be linked to degenerative neurological conditions such as Parkinson's disease, Shy-Drager syndrome, and Lewy body dementia. It can also be induced by certain drugs, including antidepressants and sedative-hypnotics.

RBD can be diagnosed through a physical and neurological exam, as well as a polysomnogram, which is an overnight sleep study that monitors various physiological parameters. Treatment for RBD involves a combination of lifestyle changes, medication, and injury prevention techniques.

What are the symptoms?

REM sleep behaviour disorder (RBD) is characterised by a loss of muscle paralysis during REM sleep, which results in people acting out their dreams. Symptoms of RBD include:

• Minor movements of the limbs
• More pronounced body movements such as punching, flailing, kicking, sitting up in bed, or jumping out of bed
• Vocalisations including talking, yelling, or screaming

People are usually unaware of these behaviours during episodes and often only find out about them from a bed partner or roommate. When awoken during an episode, people with RBD are usually alert and coherent and can recall the content of the dream.

Episodes of RBD usually occur later in the night, as REM sleep usually begins about 90 minutes after falling asleep and REM sleep stages get longer in the second half of the night. Episodes can occur once or multiple times during the night, from a few times a year to every night. RBD can develop suddenly or gradually but symptoms typically worsen over time.

RBD is often associated with other neurological conditions, such as Parkinson's disease, Lewy body dementia, and multiple system atrophy. It is also associated with the use of certain medications, including antidepressants, and substance withdrawal.

What are the causes?

The exact cause of REM sleep behaviour disorder (RBD) is unknown. However, it is often associated with other neurological conditions, including Parkinson's disease, Lewy body dementia, and multiple system atrophy. In many cases, RBD precedes the development of these neurodegenerative diseases by several years.

RBD is also linked to antidepressant use and alcohol or sedative-hypnotic withdrawal. Certain antidepressants, such as tricyclics and serotonin reuptake inhibitors, can trigger RBD. Additionally, RBD has been associated with post-traumatic stress disorder (PTSD) and traumatic brain injuries (TBI).

RBD can be divided into three categories: idiopathic RBD, drug-induced RBD, and secondary RBD due to a medical condition. Idiopathic RBD is most commonly associated with neurodegenerative diseases, while drug-induced RBD is often caused by antidepressants.

Predisposing factors for RBD include older age, male sex, narcolepsy, antidepressant use, and neurological disorders.

How is it diagnosed?

If you think you may have REM sleep behaviour disorder, it is important to consult your doctor. They will ask you questions about your symptoms and medical history. If you have a bed partner or housemate, your doctor will likely ask them questions about your sleeping behaviour as well.

Your doctor will also perform a physical and neurological exam to rule out any other potential causes, such as alcohol, medications, or narcolepsy. They may also look for symptoms of Parkinson's disease, such as hand tremors or muscle stiffness.

If you are diagnosed with REM sleep behaviour disorder, your doctor may refer you to a sleep lab for an overnight sleep study, also known as a polysomnogram. During this study, sensors will monitor your 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.

According to the International Classification of Sleep Disorders, a diagnosis of REM sleep behaviour disorder requires all of the following criteria to be met:

• Repeated episodes of sleep-related vocalisation and/or complex movement behaviours.
• Episodes occur during REM sleep, as confirmed by an in-lab sleep study or your clinical history.
• Episodes include sleep without atonia, as confirmed by polysomnography.
• The episodes are not attributed to another disorder, medication side effects, or substance abuse.

How is it treated?

REM sleep behaviour disorder (RBD) is a parasomnia disorder characterised by nocturnal complex motor behaviour and REM sleep without atonia. The treatment of RBD is twofold: symptomatic treatment to prevent injury, and prognostic counselling and longitudinal follow-up surveillance for phenoconversion toward neurodegenerative disorders.

Symptomatic Treatment

The aim of symptomatic treatment is to prevent sleep-related falls and injuries. The most common first-line therapies for RBD are clonazepam and melatonin. However, their efficiency has not been proven by randomised clinical trials. Other possible treatments include:

• Rivastigmine, memantine, 5-hydroxytryptophan, and the herbal medicine yokukansan: These have shown some degree of efficacy in short- and medium-term randomised clinical trials involving a low number of patients.
• Dopamine agonists: The role of these in improving RBD symptoms is controversial.
• Sodium oxybate: There have been some reports of clinical improvements of RBD symptoms in patients treated with this drug.
• Drugs used for the therapy of Alzheimer's disease: Some drugs in this category have shown improvements of RBD symptoms in patients with RBD associated with Alzheimer's disease.
• Antidepressant and/or serotonergic drugs: Some drugs in this category have shown improvements of RBD symptoms in patients with RBD.
• Antiepileptic drugs: There have been some reports of improvements of RBD symptoms in patients treated with antiepileptic drugs.
• Non-pharmacological therapies: For example, customised bed alarms, hypnosis, and high-intensity exercise.

What are the complications?

REM sleep behaviour disorder (RBD) can cause complications for the individual and their bed partner. The violent nature of the movements during sleep can put the individual and their bed partner at risk of physical injury. In fact, up to 90% of spouses of those with REM sleep disorder report having sleep issues, and over 60% have experienced a physical injury. The disruption to sleep can be severe enough to cause relationship problems.

In addition, RBD is often a precursor to other neurological conditions, such as Parkinson's disease, Lewy body dementia, and multiple system atrophy. One study found that 38% of men aged 50 or older with RBD eventually developed one of these conditions, usually within 13 years. That number increased to nearly 81% in a follow-up study conducted 16 years later.

Due to the risk of injury, it is important to establish a safe sleep environment. This may include removing sharp objects and weapons from the bedroom, placing padding on the floor around the bed, and moving furniture and clutter away from the bed. If the individual shares their bed, it may be recommended that they sleep in separate beds or rooms until symptoms are treated.

Frequently asked questions