Is your partner acting out dreams at night?
Rapid eye movement (REM) sleep behaviour disorder (RBD) is a common condition, where people act out dreams during sleep. Most commonly it comes on later in life and gradually becomes more frequent and movements more vigorous over years. People usually come to see a sleep specialist, like myself, once their partner is concerned about being injured or the person who is having REM behaviour disorder injuries themselves leaping out of bed or punching something by the bedside.
What is REM behaviour disorder?
REM behaviour disorder is something that is usually noticed by bed partners and fairly typical. The person sleeping, suddenly starts moving, or thrashing out during sleep and can even throw themselves out of bed. The entire episode usually only lasts a couple of seconds, and the person often wakes up and has some awareness of what has happened. Movements are usually quite purposeful such as yelling or striking out, different from sleep talking or sleep walking, which usually comes on more slowly, and can be just mumbling or more gentle movements.
During sleep the normal process is for muscles to be relaxed. During REM sleep, or dreaming sleep, muscles are usually completely paralysed. The only muscles that are active during REM sleep are the diaphragm muscles to help with breathing and muscles that move the eyeballs under the eyelids. These movements of the eyes are the rapid-eye-movements that describe this type of sleep. As muscles are paralysed during sleep, although we may have very vivid or active dreams and have a sensation of moving we do not actually move and therefore do not injure ourselves or anyone close to us while we are sleeping.
Muscles are paralysed during sleep by a signal coming from the brain to the spinal cord suppressing movement. If this signal is not present then muscles can jerk, twitch or move purposefully during dreams. This signal can get weaker as we get older, so acting out dreams is something that most commonly occurs as people get older. Some medications can interrupt this signal, particularly antidepressants like many of the common antidepressants. So, when I see a younger person with dream enactment that sounds like REM behaviour disorder I will look carefully at what medications they are taking and it is almost always secondary to a medication.
However, when this occurs in people that are older it raises the question of the development of another neurological problem. When people with REM behaviour disorder but not other symptoms have been followed for long periods of time a high proportion have been shown to go on to develop neurological problems such as Parkinson’s disease or other similar problems such as Lewy body dementia or multisystem atrophy.
Because of the concern that people who develop REM behaviour disorder will eventually develop a neurological problem, when diagnosing REM behaviour disorder, I will usually also refer people to a neurologist. This allows a neurologist to look for signs of other neurological conditions such as Parkinson’s disease as well as arranging a brain scan if they feel it is needed. It is also important that people follow up regularly to see if early signs of these disorders develop.
There are other less common conditions where REM behaviour disorder can occur such as narcolepsy. Around 50% of people with narcolepsy with cataplexy have REM behaviour disorder.
What tests are done to diagnose REM behaviour disorder?
In people reporting symptoms consistent with REM behaviour disorder I will always do a sleep study including video monitoring during sleep. The characteristics on a sleep study are ongoing muscle activity throughout REM sleep where muscle activity should usually be suppressed. There was some interesting research presented at the Sleep 2015 conference looking at analysing the patterns of muscle activity to help differentiate conditions such as Parkinson’s disease from multi system atrophy. This is very preliminary, but something that may be useful in clinical work in the next few years.
There is also some research going on to look at whether we can more accurately predict who with REM behaviour disorder will go onto develop a neurological condition. The team at Austin Health have been running a study of a PET tracer that looks at glucose metabolism in dopamine-producing areas of the brain. This study is no longer recruiting participants and hasn’t been published as yet. I have had a number of patients participate in this research and it provided helpful information, so is likely to be something that we use in clinical practice in the future.
What else could it be?
Although REM behaviour disorder is fairly typical, with a sudden onset of movement and someone purposefully acting out a dream then quickly awakening and having some awareness of what is going on, there is overlap with other things that occur during sleep such as sleep walking or sleep talking. However, sleep walking or sleep talking, which arise from non-REM sleep, usually come on gradually and people are often unaware of what has happened or if they do wake up are somewhat confused and have no recollection of what has been going on. Non-REM parasomnias typically occur in younger people, being very common in primary school aged children and occurring in around 2 in 100 healthy adults.
Nocturnal frontal lobe epilepsy or other epilepsy syndromes that occur during sleep can also appear like REM behaviour disorder. Again these usually occur in people that are younger, typically first occurring during adolescence or early adult years and people are completely unaware of their behaviours, different from REM behaviour disorder.
What can be done?
Treatment of REM behaviour disorder primarily involves maintaining a safe sleeping environment for the person with REM behaviour disorder and their bed partners. If movements are only occasional and not vigorous then nothing in particular needs to be done. However, if people are at risk of injuring themselves or their bed partner I will generally use a medication to help reduce both the frequency and vigorous nature of movements.
Clonazepam, a benzodiazepine medication, used in low-dose (0.25 to 1.0 mg), is very effective, generally working in around 85% of cases of REM behaviour disorder. There is also some research on melatonin at higher doses than typically used as a sleep aide, generally from 6.0 to 15 mg. Neither melatonin nor clonazepam have been extensively studied and good research trials in this area are lacking.
Because of the risk of REM behaviour disorder progressing to other neurological conditions if you or your partner have symptoms of REM behaviour disorder it is important to discuss it with your health professional and have the diagnosis confirmed, usually by referral to a sleep specialist and/or a neurologist.
Related posts & links:
- REM behaviour disorder – article written for GPs
- ABC news (US) story – parasomnias including RBD
- RBD video during a sleep study – movement starts around 1:12
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