Understanding The Link Between Rem Sleep And Parkinson's

REM sleep behaviour disorder (RBD) is a sleep disorder characterised by a lack of muscle atonia during the REM sleep phase, resulting in the physical enactment of dreams. RBD is a parasomnia, a sleep disorder involving unusual and undesirable physical events or experiences that disrupt sleep.

RBD is associated with other neurological conditions, including Parkinson's disease, Lewy body dementia, and multiple system atrophy. In fact, most people with isolated or idiopathic RBD will eventually develop one of these neurodegenerative conditions. RBD is thought to be one of the earliest warning signs of these conditions.

Parkinson's disease and RBD are both associated with other neurodegenerative disorders

Parkinson's disease (PD) and REM sleep behaviour disorder (RBD) are both associated with other neurodegenerative disorders. RBD is a parasomnia, a sleep disorder that involves unusual and undesirable physical events or experiences that disrupt sleep. It is characterised by the loss of the inherent muscle atonia observed during normal REM sleep, and individuals with the disorder often present with complaints of injury to themselves or their bed partner due to violent movements during sleep.

RBD is associated with a high risk of developing neurodegenerative alpha-synucleinopathy diseases, including PD, Lewy body dementia, and multiple system atrophy. RBD is found to occur, on average, 8 years before the presentation of the core motor or cognitive symptoms required for the clinical diagnosis of PD or Lewy body dementia. It is estimated that up to 90% of patients with isolated RBD will eventually develop one of the alpha-synucleinopathies.

PD is also associated with other non-motor symptoms, including sleep disorders, psychiatric syndromes, and cognitive impairment. Sleep is frequently disrupted in individuals with PD, and poor sleep quality is related to reduced mental health. RBD is disproportionately prevalent in PD, with estimates ranging from 33 to 47%.

RBD is a parasomnia

Rapid Eye Movement (REM) Sleep Behavior Disorder (RBD) is a parasomnia characterised by the loss of the usual muscle atonia that occurs during REM sleep, allowing patients to act out their dreams. This can result in injury to the patient or their bed partner, especially if the patient is acting out a violent nightmare. RBD is strongly associated with certain neurodegenerative disorders, and about 97% of people with isolated (idiopathic) RBD will have Parkinson's disease, Lewy body dementia or multiple system atrophy (MSA) within 14 years of diagnosis.

The primary treatment goal of RBD is to reduce the risk of injury to the patient and their bed partner. This can involve certain strategies and medications. Safety measures for RBD include removing sharp, glass and heavy objects from the bedroom, placing pillows between the patient and surrounding structures, and placing a mattress on the floor next to the bed in case the patient falls out of bed. If the symptoms are severe, it may be safest for the patient's bed partner to sleep in a different room.

While there are no U.S. Food and Drug Administration (FDA)-approved medications specifically for RBD, studies have shown that melatonin, clonazepam and pramipexole can reduce symptoms in some cases. Melatonin is a hormone that the pineal gland naturally makes and is essential for regulating the sleep cycle. It is considered the first-line medication for treating RBD as it rarely causes side effects. Clonazepam is a sedative and researchers aren't sure why it helps treat RBD, but most people with RBD who take a low dose of clonazepam before they sleep have few or no nightmares, vocalisations or dream enactment behaviours. Pramipexole is a dopamine agonist primarily prescribed to treat Parkinson's disease and restless leg syndrome, but recent research shows that it can help treat the symptoms of RBD.

RBD is characterised by a lack of muscle atonia during the REM sleep phase

REM sleep behaviour disorder (RBD) is characterised by a loss of muscle atonia during the REM sleep phase. This phenomenon is referred to as REM sleep without atonia (RSWA). During this phase, the body's muscles are temporarily paralysed, which prevents individuals from acting out their dreams. However, in people with RBD, this paralysis does not occur, and they may act out their dreams physically and/or vocally. This can result in injury to themselves or their bed partner.

The loss of muscle atonia during the REM sleep phase is caused by a dysfunction in the complex connections of the brainstem. Specifically, it is associated with a degeneration of neurons in the rodent sublatero-dorsal tegmental nucleus (the subcoeruleus nucleus, in humans). This degeneration disrupts the process that usually results in temporary paralysis during REM sleep.

RBD is more common in men and adults over 50

REM sleep behaviour disorder (RBD) is a sleep disorder that occurs when individuals physically act out their dreams while in the rapid eye movement (REM) stage of sleep. The disorder is characterised by dream enactment and loss of REM atonia. The movements involved in RBD can cause injury to the individual or their bed partner, especially if they are acting out a violent nightmare.

There are two main types of RBD: isolated (idiopathic) and symptomatic (secondary). Isolated RBD occurs spontaneously without an underlying cause, and most people with this type will eventually develop a neurodegenerative condition, such as Parkinson's disease, Lewy body dementia or multiple system atrophy (MSA). Symptomatic RBD happens due to an underlying cause, such as Type 1 narcolepsy.

RBD can be caused by antidepressants, which are associated with a strong increase in the disorder, particularly in early-onset cases. Other causes include narcolepsy, parasomnia overlap disorder, and inflammatory or autoimmune conditions.

The disorder can be treated with medication such as melatonin, clonazepam, and pramipexole. However, the main goal of treatment is to create a safe sleeping environment to prevent injury.

RBD is associated with worse neuropsychological functioning in PD

REM sleep behaviour disorder (RBD) is a parasomnia, a sleep disorder that involves unusual and undesirable physical events or experiences that disrupt sleep. RBD is characterised by a loss of muscle atonia during the REM sleep phase, resulting in unwanted and occasionally violent motor behaviour during dreams.

RBD is associated with worse neuropsychological functioning in Parkinson's disease (PD). PD patients with RBD (PD/RBD+) have been found to have poorer executive functioning and learning performance than PD patients without RBD (PD/RBD-). PD/RBD+ patients also have poorer neuropsychological functioning across all individual cognitive domains than healthy comparison participants (HCs). PD/RBD+ patients also demonstrate significantly worse medication management skills compared to HCs.

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