Dementia And Rem Sleep Behavior Disorder: What's The Link?

REM sleep behaviour disorder (RBD) is a parasomnia in which the normal paralysis of REM sleep is lost, causing patients to act out their dreams. It can occur at any age but symptoms usually start in people in their 40s and 50s. RBD is either idiopathic or secondary to other neurological disorders and medications.

RBD is a powerful early sign of dementia with Lewy bodies, Parkinson's disease, and multiple system atrophy. It is observed in 25% to 58% of patients diagnosed with Parkinson's, 70% to 80% of patients with dementia with Lewy bodies, and 90% to 100% of those with multiple system atrophy.

In a long-term study of 1,280 patients with RBD who didn’t have parkinsonism or dementia, researchers found that 73.5% of those with RBD had developed a related neurodegenerative disorder after 12 years.

REM sleep behaviour disorder (RBD) is a parasomnia, with abnormal dream-enacting behaviour during the rapid eye movement (REM) sleep

The diagnosis of RBD requires the combination of dream enactment behaviour, by history or by observation during a sleep study on video manometry, and confirmation of REM sleep without atonia (RSWA) on polysomnography (PSG). The diagnosis of RBD comprises two features: loss of normal atonia during REM sleep and dream enactment behaviour. The suspicion of RBD is usually due to presentation consistent with dream enactment behaviour. The diagnosis requires, however, confirmation with in-lab polysomnography (PSG) with video recording.

The primary treatment goal of RBD is to reduce the risk of injury to the patient and bed partners. Changing routine sleep habits may prove challenging for the patient and their bed partners. Their risk for injury, however, needs to be emphasised. Patients and sleeping partners should be educated on the following:

• Mitigating fall risk by lowering the bed closer to the floor
• Safe-guarding any firearms, knives, and other weapons
• Cushioning or padding the floor or sharp furniture surfaces
• Placing patients in restraining clothes or sleeping bags
• Separating the sleeping partner from the patient to reduce the risk of injury

Based on current guidelines from the American Academy of Sleep Medicine (AASM), the recommended pharmacological treatment of isolated RBD in adults is immediate-release melatonin, clonazepam, or pramipexole (Conditional recommendation). Melatonin is an endogenous hormone secreted from the pineal gland associated with circadian rhythm, and its secretion is influenced by light exposure. Although the mechanism of action is unclear, 3 to 12 mg of melatonin at bedtime is recommended and appears effective in reducing RBD symptoms. Clonazepam is an effective treatment for RBD and has been considered for a long time as first-line pharmacological therapy.

RBD is a core clinical feature of dementia with Lewy bodies (DLB) and may occur either in advance or simultaneously with the onset of DLB

REM sleep behaviour disorder (RBD) is a parasomnia, with abnormal dream-enacting behaviour during the rapid eye movement (REM) sleep. RBD is either idiopathic or secondary to other neurologic disorders and medications. Dementia with Lewy bodies (DLB) is the third most common cause of dementia, and the typical clinical presentation is rapidly progressive cognitive impairment. RBD is one of the core features of DLB and may occur either in advance or simultaneously with the onset of DLB. The association between RBD with DLB is widely studied. Evidences suggest that both DLB and RBD are possibly caused by the shared underlying synucleinopathy.

RBD is a risk factor for developing mild cognitive impairment (MCI) and dementia

REM sleep behaviour disorder (RBD) is a parasomnia, with abnormal dream-enacting behaviour during the rapid eye movement (REM) sleep. RBD is a risk factor for developing mild cognitive impairment (MCI) and dementia. People with isolated REM (RBD) have a high lifetime risk of developing a neurodegenerative disease, including dementia, but disclosure of this risk remains controversial.

RBD is a core clinical feature of dementia with Lewy bodies (DLB) and may occur either in advance or simultaneously with the onset of DLB. The association between RBD with DLB is widely studied. Evidences suggest that both DLB and RBD are possibly caused by the shared underlying synucleinopathy.

RBD is also acknowledged as a core clinical feature of Parkinson's disease (PD). RBD not only precedes or coincides with the onset of PD but also occurs during the course of the progression. The cooccurrence of RBD, DLB, and PD is an important topic.

RBD can be either idiopathic and a marker of prodromal neurodegeneration or secondary to neurodegeneration. Longitudinal studies of idiopathic RBD had shown evidence of a strong association with eventual phenoconversion to a neurodegenerative disease. Phenoconversion risk between two and five years is about 15% to 35%, and the risk may increase to 41% to 90.9% if extending the follow-up period up to 12 to 25 years.

Among the 246 subjects, 47 (19.1%) had pRBD at the baseline, and pRBD group was younger and with male predominance. During 4-year follow-up, there was no significant differences in the rate of decline in neuropsychological measures. Patients with pRBD performed generally poorer in visuoconstructional, visuoperceptual, and executive/attention tests in comparison to RBD negative.

RBD is associated with cognitive dysfunctions

• Global cognitive function
• Long-term verbal recall
• Long-term verbal recognition
• Generativity
• Inhibition
• Shifting
• Language
• Visuospatial/constructional ability
• Psychomotor ability

RBD is observed in 25% to 58% of patients diagnosed with Parkinson’s, 70% to 80% of patients with DLB and 90% to 100% of those with multiple system atrophy

REM sleep behaviour disorder (RBD) is a parasomnia in which people act out their dreams. It is characterised by the loss of normal muscle atonia during REM sleep, and can present as limb movements and/or vocalisations that reflect dream content. RBD is an early feature of several neurodegenerative diseases, including Parkinson's disease, dementia with Lewy bodies (DLB), and multiple system atrophy.

RBD is observed in 25% to 58% of patients diagnosed with Parkinson's, 70% to 80% of patients with DLB, and 90% to 100% of those with multiple system atrophy.

Parkinson's Disease

RBD often precedes the onset of Parkinson's disease and other parkinsonian symptoms by several years. One study found that the median latency from RBD onset to a diagnosis of neurodegenerative disease was 11 years, with a range of 2 to 24 years. The median time from RBD diagnosis to neurodegenerative disease diagnosis was 7.5 years. Another study found that 33.1% of patients with RBD developed a neurodegenerative disease within 5 years, 75.7% within 10 years, and 90.9% within 14 years.

Dementia with Lewy Bodies

RBD is considered a core clinical feature of DLB, and its inclusion in the diagnostic criteria improves the accuracy of DLB diagnoses. One study found that patients with probable RBD were 6 times more likely to have autopsy-confirmed DLB than other neurodegenerative dementia conditions. The addition of RBD to the diagnostic criteria increased the sensitivity of DLB diagnoses from 85% to 88%, and to 90% when dementia and RBD were designated as probable DLB.

Multiple System Atrophy

Multiple system atrophy is a rare neurodegenerative disorder that affects the brain and the nervous system. RBD is a common feature of multiple system atrophy, with a prevalence of up to 90%.

Frequently asked questions