Nancy is a woman in her late 60s who suffers from a sleep disorder. What makes her case unique is that her particular sleep disorder is quite frustrating and difficult to treat. Nancy has REM sleep behavior disorder (RBD).
Her sleep challenges started with an instigating traumatic event at work that left her with psychological post-trauma issues. She then underwent knee surgery and during the recovery period she was unable on one occasion, to get up from the toilet and she fell and hit her head. It is not clear which of these (or perhaps all of them together) were the causative events, but that is when the RBD symptoms began.
The symptoms typically consist of violent movements and flailing of the arms and legs during dream periods. This became a serious problem with her bed partner, and it lead to the present situation of not only sleeping in separate beds, but also in separate rooms. The reason for the arrangement is that along with these “movement episodes” she also started sleep walking. She now sleeps in a bed that has rails.
When Nancy shared her trauma and sleep history, it was evident to the doctor that she needed a sleep study to help with a diagnosis. With a sleep study, there’s the potential to look for traditional findings that might suggest sleep apnea (breathing patterns), but also the opportunity to examine the REM periods to see whether muscle activity is dormant as expected, or not, which would confirm RBD.
What is REM and what is its purpose in the sleep process?
Rapid eye movements, or REM, is a period during sleep that has much instability, with alternating fast and slow heart rates and mixed brain frequency waves. These findings are in direct contrast to the predominant non-REM stage findings of sleep, where “everything slows down.” REM periods are considered by some as a way of acting as if you’re awake while you sleep. During REM there is desensitization to emotional experiences you may have had that day, while they are paired with previous experiences, and this process is ultimately manifested as dreams. It is a necessary (sleep) period that helps individuals to achieve mental and emotional stability.
In order to protect oneself during this intense emotional period, the brain actually sends signals to the spinal cord to paralyze all the muscles (except for the respiratory and eye muscles) at the start of REM. So normally, an individual should be motionless during REM periods.
What is REM sleep behavior disorder or RBD?
For a variety of reasons this (normal) muscle inhibition does not happen during the person’s REM periods, so individuals are free to move and physically enact their dreams during sleep. This can clearly present safety concerns as illustrated by Nancy’s symptoms and her behaviors described above. In many cases, it’s the bed partner who is the victim of the physical consequences (they can be hit inadvertently).
What is the purpose of doing a sleep study?
In order to define the different stages of sleep in the study, one looks at specific features that define certain stages. The way to recognize REM periods during the sleep study is by identifying specific waves in the eye movements and separately, the electromyogram (EMG) component of the study measures muscle tone. During “awakenings” the waves become very coarse and active (suggesting more significant physical activity) while during REM periods you would normally expect to see very fine waves or lines, demonstrating just how inactive the muscles are.
In individuals who have RBD, the line representing the brain waves during REM, aren’t thin but rather coarse and active.
What are the most common causes of RBD?
The exact causes are not known but there is general agreement among experts that RBD is the precursor to neurodegenerative disorders including Parkinson’s disease and another condition that results in degeneration of nerve cells causing dementia, called Lewy Body Dementia.
RBD is also associated with the use of certain antidepressant medications such as imipramine (tricyclic), Prozac, and Zoloft, both of which are serotonin reuptake inhibitors. These are common drugs, so it’s important for patients and health practitioners to be on the lookout for possible RBD.
RBD can also be the consequence of a “rebound” after serious or persistent sleep deprivation, and it can occur during alcohol withdrawal.
Is there an association of RBD with head trauma?
There is no clear evidence linking this particular condition with head trauma events. Head trauma has been linked with other sleep disorders including narcolepsy and central sleep apnea. This observation is of particular importance in the case of Nancy since she did also experience head trauma.
What is the current treatment of RBD?
Unfortunately, there are few medication treatment options. Some patients do respond to Clonazepam. Nancy is currently taking this medication but has not experienced significant benefits. Some patients do achieve relief when taking melatonin.
The most important part of management is taking measures to assure safety for the individual and the bed partner (separate beds or separate sleeping arrangements). Knowing if you may have a higher risk allows for some mitigation or at minimum, early diagnosis if the patient identifies certain symptoms or complaints.
RBD is just one of a group of undesirable phenomena that occur during sleep, which are collectively known as parasomnias. Included in this group are night terrors, sleep paralysis, hypnagogic hallucinations, and nightmare disorder.
Sleep experts like me are tasked with evaluating and identifying these individual and sometimes complicated conditions so patients can ultimately experience restful, restorative uninterrupted sleep.