Questions & Answers
RBD CAUSES AND MECHANISMS
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The different neurodegenerative diseases that are associated with RBD involve similar biology, consisting of the abnormal deposition of alpha-synuclein in the central and peripheral nervous system. However, their manifestations differ based on the diversity of where that alpha-synuclein is deposited. Despite this diversity, they all cause RBD because of alpha-synuclein deposition in the brainstem areas that control REM sleep.
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RBD is much more common in individuals with synucleinopathies (including Parkinson disease, Lewy body dementia, and multiple system atrophy) compared to other neurodegenerative diseases. However, RBD can occur in individuals with frontotemporal lobar degeneration, corticobasal degeneration, progressive supranuclear palsy, and Alzheimer disease. Among protein aggregates that are associated with neurodegenerative diseases, alpha-synuclein is the most strongly associated with RBD. Many individuals have various amounts of multiple protein aggregates, rather than a single type of aggregate, and additional research is needed to understand how alpha-synuclein and other protein aggregates are involved in the risk and progression of RBD and other neurologic illnesses.
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Yes, the main protein component of Lewy bodies is misfolded alpha-synuclein protein. Similar to the prion protein involved in Creutzfeldt-Jakob disease (CJD) and bovine spongiform encephalopathy (BSE or “mad cow disease”), alpha-synuclein is a normal brain protein, which can become misfolded (through ways that are still not completely understood) and contribute to disease. However, there are no documented cases of transmission of REM sleep behavior disorder or other synucleinopathies between humans through routine contact.
RBD DIAGNOSIS
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Currently, most geneticists do not recommend genetic testing for individuals with isolated RBD, mainly because genetic risk factors are still not completely understood and results do not change clinical management. Individuals who also have a strong family history of a related illness like Parkinson disease may want to discuss referral to a geneticist with their neurologist or primary care provider.
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There are a number of steps involved in RBD diagnosis, any of which can cause diagnostic delays or difficulties. First, the symptoms must be recognized as a specific neurologic disorder for which medical evaluation should be sought. Some people with RBD never ask a physician about their symptoms and so never get diagnosed. Second, not all physicians have had exposure to diagnosing the condition during their training and may not make the appropriate referral. Finally, diagnosis of RBD by a sleep specialist involves evaluating the potential role of other factors, like medication use, unrecognized neurodegenerative disease or sleep apnea, that can impact the symptoms of RBD. It also must be differentiated from a seizure disorder, a psychiatric disorder or a NREM sleep disorder, which may be treated differently and have a different prognosis.
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Yes. A sleep study demonstrating REM sleep without atonia is necessary to diagnose RBD, because other disorders can cause extensive movement in sleep (e.g., recognized or, sometimes, unrecognized post-traumatic stress disorder), sometimes with dream content. Although a spouse or bedpartner can provide invaluable corroboration as to the person’s nighttime behaviors, the identification of REM sleep, made with the appropriate polysomnographic equipment, remains necessary for defining the condition. Newer developments in wearable technology may hold promise in the future, but these remain to be fully tested at this time.
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PSG can rule in and it can sometimes rule out a diagnosis depending upon the situation. Having a conversation with your doctor about the PSG findings is most important in order to get to those nuanced issues pertinent to PSG confirmation of RBD.
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We advise that you have a conversation with the doctor to find out what this means.
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We are unable to advise on this forum about your specific situation, and suggest that you have a conversation with a sleep doctor. Getting out of bed, walking to your car and driving is unlikely to be RBD but it warrants a visit with a sleep doctor.
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Not necessarily. You can have a lot of REM sleep and no RBD or a little REM sleep and severe RBD.
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Yes, there are ongoing research efforts to enable diagnosing RBD in home settings and significant progress has been made in this area.
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We rarely use PET scans in RBD. Sometimes we use a DaTscan to see if someone with RBD has a dopamine deficit which would suggest underlying parkinsonism. MRI scans are used to evaluate for brain structure, and MRI abnormalities which are not typically present in isolated RBD.
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Seek out medical care if you or a family member were having any behaviors that could possibly lead to injury such as jumping out of bed, etc.
RBD and SYNUCLEINOPATHY RISK
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We cannot be specific on risk for each individual situation. The most important factors are the young age and the possible venlafaxine trigger. Each of these factors would probably cut the risk by half or so. Overall, the risk is 6-8% per year, so obviously this situation would have a much lower risk.
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We cannot offer individual advice. In general, the link between possible neurological disease relies upon measuring early signs of that disease. For example, measures such as olfactory loss, autonomic changes (orthostatic hypotension, but not necessarily POTS), and motor/cognitive changes are the best signs that neurological disease may be associated with RBD. Several tests are available on a research basis as well, which can help identify early stages of neurologic disease.
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The timeline has not really changed much since the landmark publications of 5-10 years ago. The overall risk per year is about 6% depending on the study. As the disorder is being recognized earlier, we anticipate that some people may be coming to medical attention earlier than previously - that would probably result in a gradual lowering of the risk estimates.
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There is an association between how long RBD symptoms have been present and likelihood of phenoconversion, such that the longer someone has had RBD symptoms, the more likely they are to phenoconvert. But there is a lot of variability within this — some people phenoconvert very soon after RBD symptom onset, some people phenoconvert after many years, and some people never phenoconvert. So the amount of time symptoms have been present isn’t by itself a very useful predictor of when or if phenoconversion will occur. Our understanding of when and how RBD symptoms emerge continues to evolve. In some cases, initiating certain classes of medications or the simultaneous presence of other sleep disorders (like sleep apnea) may play a role in the emergence of RBD symptoms.
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No, current evidence may, in fact, suggest the opposite. People who are young (less than 50 years old) when RBD develops appear less likely to develop neurodegenerative diseases than those who are over 50. These findings, however, may be limited by the fewer years of follow-up available for those younger people.
RBD CLINICAL FEATURES
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Yes, orthostatic hypotension and other autonomic symptoms can occur in individuals with RBD. Symptoms of lightheadedness, constipation, and incomplete urinary emptying or incontinence should be discussed with the individual’s neurologist or primary care provider.
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Urinary hesitancy can indicate autonomic dysfunction, which is common in individuals with RBD, but there are multiple non-neurologic contributors as well, so this should be discussed first with the primary care provider.
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Yes, loss of sense of smell is a common early symptom in individuals with RBD. However, there are many non-neurological contributors to loss of smell, so this should be discussed with the primary care provider, with consideration of referral to a neurologist as needed.
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Yes, confrontations including chasing and fighting are common dream contexts for individuals with RBD. It is important for individuals and bed partners to report this to their primary care provider, and to take steps to minimize injuries, including moving or padding sharp corners near the bed, and ensuring no dangerous objects are near the bed.
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Antidepressants generally increase movements during night and particularly can increase the severity of RBD. Paradoxically, they can also reduce some people’s RBD, simply by reducing REM sleep (most antidepressants reduce REM sleep). There is no evidence that antidepressants increase the risk of Parkinson’s or cognitive impairment in RBD, so many people who need to take them will continue to do so, just taking close care of the safety issues in their sleeping environment.
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There is a lot of research on the relationship between PTSD and RBD. I suspect that there are some with PTSD who act out their dreams simply because of the strength of the bad dreams themselves - they might even have relatively normal REM atonia. On the other hand, any source of anxiety or stress can increase nightmares, so even those with ‘regular’ RBD will have increases during periods of stress. It is hard to say if the differences between PTSD and non-PTSD are strong enough to generate a separate subtype category, but this is definitely being considered.
RBD TREATMENT
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The usual treatments for RBD all apply. One particularity to PTSD-related RBD is to reduce the intensity of nightmares. Some clinicians use prazosin for this. However, we are unable to provide individualized advice on clinical care, and suggest that you have a conversation with your primary physician or sleep doctor.
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Some start melatonin at 3-5mg 30 minute prior to bedtime and increase by 3-5mg at a time to a max dose of 12mg. Above this, some have found melatonin less effective for RBD. For clonazepam, starting with 0.25mg and increase by 0.25mg if necessary to a maximum of 1mg is common. Above this dose, side effects of cognitive impairment and gait instability become a significant risk. Another option may be using rivastigmine patch, starting at 4.6mg transdermally. However, we are unable to provide individualized advice on clinical care, and strongly suggest discussing RBD treatment with your primary physician or sleep doctor.
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Pramipexole for RBD is not commonly used. Potential side effects of Pramipexole include sleepiness and mood dysregulation. In general, melatonin is safe treatment option for RBD; however, we are unable to provide individualized advice on clinical care, and strongly suggest discussing RBD treatment with your primary physician or sleep doctor.
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Relying on medications for "quality" sleep is not recommended. There are medications that can help with sleep onset, however what to recommend depends on the specific situation. We are unable to provide individualized advice on clinical care, and strongly suggest discussing RBD treatment with your primary physician or sleep doctor.
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At this time, we are not aware of any data addressing this topic. We strongly suggest discussing RBD treatment with your primary physician or sleep doctor.
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At this time, we are not aware of any data on this topic. It is best to discuss RBD treatment with your primary physician or sleep doctor.
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We are not familiar with the study referenced and are unaware of any such finding at this time.
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Regardless of whether you are enrolled in a study, it is likely that a combination of lifestyle and medical management will be the best next steps for RBD. You can refer to our recent review article reviewing various risk factors, some of which are modifiable by lifestyle or medical changes, and the evidence behind these commendations:
Lee E. Neilson, Joseph F. Quinn, Miranda M. Lim (2023). Screening and Targeting Risk Factors for Prodromal Synucleinopathy: A Prescriptive Multi-modal Framework. Aging & Disease. PMID: 37309872