How Many With Rem Sleep Disorder Develop Pd?

REM sleep behaviour disorder (RBD) is a sleep disorder characterised by dream enactment and loss of REM atonia. It is a parasomnia, a sleep disorder that involves unusual and undesirable physical events or experiences that disrupt sleep. RBD is a prodromal symptom of Parkinson's disease (PD), meaning it can occur well in advance of other symptoms of PD. It is present in 25-58% of patients with PD and up to 90% of those with Lewy Body Dementia or Multiple System Atrophy. RBD is a strong predictor of PD, with one source stating that 97% of people with isolated RBD will have PD within 14 years of their RBD diagnosis. Another source estimates that 30% of people with RBD will develop PD within 3 years, rising to 66% within 7.5 years.

The link between REM sleep behaviour disorder and Parkinson's disease

REM sleep behaviour disorder (RBD) is a sleep disorder characterised by dream enactment and loss of REM atonia. Individuals with RBD may injure themselves or their bed partner due to violent movements during sleep. RBD is linked to Parkinson's disease (PD) and is considered a prodromal symptom of PD, meaning it can occur before other symptoms of the condition.

RBD is associated with a high risk of developing neurodegenerative diseases, including PD. Over 70% of people with RBD will develop PD or dementia within 12 years of their diagnosis. RBD is found to occur, on average, eight years before the presentation of the core motor or cognitive symptoms required for a PD diagnosis.

RBD is characterised by the loss of the inherent muscle atonia observed during normal REM sleep. This phenomenon is referred to as REM Sleep without Atonia (RSWA). RSWA is often an incidental finding in sleep studies, but it forms the basis of the dream enactment behaviour that defines RBD. During RBD, individuals experience vivid dreams that they act out during sleep. While dream enactment and limb movements during sleep can occur in the healthy population, the chronicity of symptoms is a key distinguishing factor of RBD.

RBD can be violent and aggressive, resulting in violent motor behaviours that may pose a threat to the individual with RBD or their bed partner. Anecdotal reports describe individuals kicking, punching, biting, or strangling their bed partners during sleep. However, more systematic studies have revealed that violent dreams and behaviours make up a small percentage of all events.

The frequency of motor events in RBD can vary from multiple episodes per night to one episode per month, and the severity and frequency of behaviours may vary from night to night and over the course of the condition. The mechanisms behind this fluctuation are currently unknown.

RBD may be idiopathic (iRBD) or secondary to another condition. iRBD is often referred to as 'isolated RBD' and occurs spontaneously without an underlying cause. Most people with iRBD will eventually develop a neurodegenerative condition, specifically PD, Lewy body dementia, or multiple system atrophy (MSA). These conditions are called alpha-synucleinopathies.

Symptomatic or secondary RBD occurs due to an underlying cause, such as Type 1 narcolepsy or the use of certain antidepressants. When a person has both an alpha-synucleinopathy and RBD, it is considered secondary RBD.

Prevalence

RBD is relatively rare, affecting about 1% of the general US population and 2% of people aged 50 or older. These rates may be higher as RBD can be difficult to diagnose, and almost half of people with the condition are unaware they have it.

Among people over 50, men are nine times more likely than women to have RBD. About 97% of people who have isolated RBD will have PD, Lewy body dementia, or MSA within 14 years of diagnosis.

Diagnosis and Treatment

To receive an RBD diagnosis, individuals typically undergo an in-lab video sleep study or polysomnogram (PSG). PSG records specific body functions during sleep, such as breathing rate, airflow, brain wave activity, and muscle movements of the chin and upper extremities.

The main goal of RBD treatment is to create a safe sleeping environment. This can involve safety measures such as removing sharp objects from the bedroom and padding the floor around the bed. If symptoms are severe, it may be safest for the individual's bed partner to sleep in a separate room.

Medications such as melatonin, clonazepam, and pramipexole can also help reduce RBD symptoms. Melatonin is considered the first-line medication for treating RBD as it rarely causes side effects. Clonazepam is a sedative that has been clinically proven to be the most effective prescription medication for RBD, but it can cause cognition problems and falls. Pramipexole is a dopamine agonist primarily prescribed to treat PD and restless leg syndrome. Recent research suggests that it can also help treat RBD symptoms.

The prevalence of REM sleep behaviour disorder in the general population

REM sleep behaviour disorder (RBD) is characterised by the loss of normal muscle atonia during REM sleep, resulting in patients acting out their dreams. It is a parasomnia, a sleep disorder that involves undesirable physical events or experiences that disrupt sleep. RBD is strongly associated with certain neurodegenerative disorders, particularly Parkinson's disease, Lewy body dementia, and multiple system atrophy.

RBD is relatively rare, affecting about 1% of the general US population and 2% of people aged 50 or older. However, these rates may be higher in reality, as RBD can be difficult to diagnose, and almost half of those with the condition are unaware they have it.

The challenges of diagnosing REM sleep behaviour disorder

REM sleep behaviour disorder (RBD) is a parasomnia, a sleep disorder that involves unusual and undesirable physical events or experiences that disrupt sleep. People with RBD act out their dreams physically and/or vocally during the rapid eye movement (REM) stage of sleep, and are unaware of their actions. The movements involved in RBD can cause injury to the person or their bed partner, especially if they are acting out a violent nightmare.

There are several challenges to diagnosing RBD. Firstly, it is a relatively rare condition, affecting about 1% of the general US population and 2% of people aged 50 or older. This means that many healthcare providers may not be familiar with the condition or its diagnostic criteria. Additionally, RBD can be difficult to officially diagnose, and almost half of people with the condition do not realise they have it. This may be because the symptoms of RBD can vary in severity, ranging from mild muscle twitches to more violent movements such as punching or kicking. Many people only find out they have RBD when they are told about their symptoms by a bed partner or roommate, or when they wake up with an injury.

Another challenge in diagnosing RBD is that it often coexists with other neurological conditions, such as Parkinson's disease, Lewy body dementia, or multiple system atrophy. In fact, RBD is considered a marker of prodromal Parkinson's, as it often precedes the onset of motor symptoms. Therefore, it can be challenging to determine whether RBD is occurring in isolation or as a symptom of another disorder. Furthermore, certain medications, such as antidepressants, can cause RBD, further complicating the diagnostic process.

To receive a diagnosis of RBD, a person must meet specific criteria, including repeated episodes of acting out dreams with vocalisations or arm and leg movements, and the absence of muscle paralysis during REM sleep. Polysomnographic video recording is the most important diagnostic test for RBD and is usually conducted in a sleep study centre. This test monitors various parameters, including the electrical activity of the brain and heart, muscle movements, eye movements, and respiratory movements, to identify characteristic patterns associated with RBD. However, accessing a sleep study centre and undergoing overnight monitoring can be inconvenient and costly, creating another barrier to diagnosis.

In summary, diagnosing RBD can be challenging due to its rarity, variable symptoms, coexistence with other neurological conditions, and the need for specialised diagnostic tests. Raising awareness of RBD among healthcare providers and the general public, as well as improving access to diagnostic resources, could help address these challenges and ensure timely and accurate diagnoses.

The treatment options for REM sleep behaviour disorder

REM sleep behaviour disorder (RBD) is a parasomnia disorder characterised by nocturnal complex motor behaviour and polysomnographic REM sleep without atonia. The main goal of treatment for RBD is to create a safe sleeping environment for the patient and their bed partner. This can involve safety measures and medication.

Safety Measures

• Removing sharp, glass and heavy objects from the bedroom
• Placing pillows between the patient and surrounding structures, such as the headboard or a nightstand
• Placing a mattress on the floor next to the bed in case the patient falls out of bed, or using padded bedside rails
• Sleeping in a sleeping bag
• If symptoms are severe, the patient may need to sleep alone in a different room
• Avoiding alcohol, as this can trigger an RBD episode and make the condition worse

Medication

There are no U.S. Food and Drug Administration (FDA)-approved medications specifically for RBD. However, studies have shown that the following medications can reduce symptoms in some cases:

• Melatonin: This is considered the first-line medication for treating RBD as it rarely causes side effects. It is recommended to start at a baseline dose and then increase until symptoms improve.
• Clonazepam: A sedative that has been shown to reduce nightmares, vocalisations or dream enactment behaviours in people with RBD. It can cause unpleasant side effects, so it may only be prescribed if melatonin is ineffective.
• Pramipexole: A dopamine agonist that has been shown to be effective in treating the symptoms of RBD.

Other medications that have been found to be effective in treating RBD in some cases include temazepam, lorazepam, zolpidem, zopiclone, donepezil, ramelteon, agomelatine, cannabinoids, and sodium oxybate.

The prognosis for people with REM sleep behaviour disorder

Isolated RBD is a strong indicator of future neurodegenerative disorders. Studies indicate that 97% of people with isolated RBD will develop Parkinson's disease, Lewy body dementia, or multiple system atrophy within 14 years of their RBD diagnosis. Therefore, people with isolated RBD should be regularly monitored for signs of these neurological conditions.

Symptomatic RBD is often linked to narcolepsy, which is characterised by a lack of orexin, a brain chemical that regulates sleep, wakefulness, and appetite. It can also be caused by the use of certain antidepressants, which can cause imbalances in dopamine and serotonin, affecting REM sleep.

Regardless of the type of RBD, the prognosis is influenced by the severity of symptoms, the occurrence of injuries, and whether the disorder is treated or untreated. RBD can cause serious injuries to the person affected or their bed partner, so seeking treatment is crucial. Treatment focuses on creating a safe sleeping environment and may include safety measures such as removing hazardous objects from the bedroom and using padded bedside rails. In severe cases, medication may be prescribed to manage symptoms.

People with RBD and a neurological condition often have a poorer prognosis. For example, those with early Parkinson's disease and RBD have a lower quality of life than those with early Parkinson's disease alone. Additionally, RBD can lead to frequent sleep disruptions, negatively impacting overall sleep quality.

Frequently asked questions