From the Guidelines
RBD episodes occurring in stage 3 (slow wave) sleep are less likely to represent true REM Behavior Disorder and therefore less likely to be associated with future development of Parkinson's disease or other synucleinopathies. True RBD occurs specifically during REM sleep, not during slow wave sleep. Episodes of abnormal movements or behaviors during stage 3 sleep are more likely to represent disorders of arousal such as confusional arousals, sleepwalking, or sleep terrors. These parasomnias arise from non-REM sleep and do not carry the same risk for neurodegenerative disease that RBD does. For a definitive diagnosis, polysomnography is essential to determine whether the episodes occur during REM or non-REM sleep. If episodes are confirmed to occur during stage 3 sleep, further evaluation for other sleep disorders would be appropriate rather than focusing on concerns about future Parkinson's disease. The distinction is important because approximately 80-90% of patients with true RBD eventually develop Parkinson's disease or related disorders, whereas non-REM parasomnias do not carry this risk 1.
Some key points to consider:
- RBD is typically characterized by abnormal or disruptive behaviors emerging during rapid eye movement (R) sleep having the potential to cause injury or sleep disruption 1.
- Patients with RBD are at risk for sleep-related injury (SRI) and may develop α-synucleinopathies, such as Parkinson's disease, dementia of Lewy body type, and multiple system atrophy 1.
- The diagnosis of RBD can be confirmed by polysomnography (PSG), which shows loss of normal electromyographic (EMG) atonia (REM sleep without atonia–RSWA) 1.
- Treatment options for RBD include clonazepam, immediate-release melatonin, pramipexole, and rivastigmine, with the choice of medication depending on the patient's underlying disease and attendant symptoms 1.
In terms of management, the American Academy of Sleep Medicine clinical practice guideline recommends the use of clonazepam, immediate-release melatonin, and rivastigmine for the treatment of RBD 1. However, the choice of medication should be individualized based on the patient's specific needs and circumstances. It is also important to note that RBD episodes occurring in stage 3 sleep are less likely to represent true RBD and may require further evaluation for other sleep disorders. Overall, a comprehensive approach to diagnosis and treatment is necessary to manage RBD effectively and reduce the risk of sleep-related injury and neurodegenerative disease.
From the Research
RBD Episodes and Sleep Stages
- RBD episodes typically occur during the REM stage of sleep, which is the stage where dreams occur and brain activity is similar to that of being awake 2, 3.
- The fact that RBD episodes are happening in the 3rd stage of sleep, also known as non-REM sleep or slow-wave sleep, is not typical for RBD, as RBD is characterized by the loss of muscle atonia during REM sleep 2, 4.
Association with Parkinson's Disease
- RBD is strongly associated with the development of Parkinson's disease and other neurodegenerative disorders, such as dementia with Lewy bodies and multiple system atrophy 2, 3, 5.
- Studies have shown that a significant proportion of patients with idiopathic RBD will eventually develop an overt neurodegenerative syndrome, with an overall conversion rate of 6.3% per year 3.
- However, the fact that RBD episodes are occurring in the 3rd stage of sleep, rather than the REM stage, may suggest a different underlying mechanism or a lower risk of developing Parkinson's disease or other neurodegenerative disorders 4, 5.
Diagnosis and Management
- A clinical history of dream enactment or complex motor behaviors, together with the presence of muscle activity during REM sleep confirmed by video polysomnography, is mandatory for a definite RBD diagnosis 2.
- Management of RBD typically involves counseling and pharmacologic measures, such as clonazepam and/or melatonin, to suppress unpleasant dreams and behaviors and improve bedpartner quality of life 2, 6, 4.