REM Sleep Behavior Disorder: A Parkinson’s Wake-Up Call
Sleep and PD: A bidirectional link
Sleep disturbances are common in those with Parkinson’s disease (PD). Sleep disorders are also thought to be influential over neurological health. For instance, if you don’t get enough deep sleep (due to insomnia, sleep apnea, or restless legs), you may be creating fertile territory for a degenerative condition like PD to take root. Deep sleep (also called slow-wave, N3, or delta sleep) provides our body with the most restorative sleep and contribute to damage repair and toxin removal in the brain.
Plenty of people with sleep disorders never develop PD. However, one specific sleep disorder is known to correlate with PD – REM sleep behavior disorder (RBD).
What is REM Sleep Behavior Disorder (RBD)?
It may seem like sleepwalking, but RBD is, by definition, not a sleepwalking disorder. RBD involves dream enactment behavior.
The difference between sleepwalking and RBD is subtle, but important: sleepwalking typically takes place in non-REM and transitional stages of sleep, whereas RBD takes place during REM (rapid-eye-movement) sleep.
Sleepwalking and non-REM sleep
Dreams rarely occur during non-REM sleep. Even if sleepwalkers do dream, they typically do not remember their dreams or act them out. Usually, a loved one reveals that they walked (or ate food, or texted, or initiated sex) during their sleep. Those who sleep alone may awaken in a different place than where they fell asleep, with some evidence of their activities.
Dream enactment in REM sleep
RBD is different. It only occurs during REM (or dream) sleep. One remarkable (and normal) phenomenon that occurs in REM sleep is the body’s natural paralysis from the chin down (excluding the heart and diaphragm). During REM sleep, one should not be able to move any muscles. Dream enactment behavior, then, implies a major neurological disconnect between the brain and body during sleep.
Also intriguing – people with RBD can be very much aware of their dream content as they act it out. They may describe it as being awake and asleep simultaneously. Unlike sleepwalkers, once awakened, people with RBD can recall vivid details of their dreams.
Unfortunately, RBD can be aggressive, violent and nightmarish, leading to injuries to both the sleeper and anyone else nearby. It can even lead to property damage.
You may recall that actor Alan Alda recently shared his PD diagnosis. The problem which inspired his journey to diagnosis was dream enactment behavior, which he said preceded other PD motor symptoms like tremor.
Comic Mike Birbiglia’s autobiographical film, Sleepwalk With Me, recounts his RBD onset, which occurred during his first comedy tour. He was inspired to tell his story after bursting through a second-story hotel window while acting out a dream.
Recent research on PD and RBD
Researchers have, for a while now, confirmed the link between PD and RBD.
A faster motor progression and higher risk for cognitive decline is more common among people with PD who also have RBD.
A 2018 Journal of Sleep Research study suggests that as many as 42 percent of all people with PD are affected by RBD.
Finally, RBD is considered a prodromal symptom of PD, meaning it can happen well in advance of other untoward symptoms linked to this condition.
New PD subtypes in development
New classifications of patients with PD may improve both diagnostics and the accuracy of predicted outcomes.
A newly developed system of three subtypes focuses on the severity of key motor and non-motor symptoms and highlights RBD as a relevant non-motor marker.
Thomas Warner MD (University College London Queen Square Institute of Neurology) told Medscape Medical News recently that “We have found that it is possible to accurately predict prognosis, disability, and survival of patients with Parkinson’s disease by classifying them into different clinical subtypes at the time of diagnosis.”
Warner, senior author of a new study published in January 2019 at JAMA Neurology, defines these subtypes as:
- Mild-motor predominant (49 percent). These patients experience motor problems; their prognosis and survival rates are considered the best.
- Diffuse malignant (16 percent). These patients experience a combination of motor and non-motor problems; they’re more likely to follow a more aggressive disease progression.
- Intermediate (35 percent). These patients don’t fit inside criteria 1 or 2 with expected outcomes fall somewhere in between.
People with PD who also have RBD will likely fall into subtype 2. However, this distinct symptom can help chart a clearer treatment path and prepare you for a more aggressive clinical approach.
Warner said that, “Together with the classical motor features, a simple assessment of relevant non-motor symptoms can now allow clinicians to provide an accurate estimation of the disease course at the time of diagnosis, allowing better counseling, management of symptoms, and planning care of potential complications.”1
If you experience sleepwalking or dream enactment behaviors
Consider these relevant scenarios:
- You experience dream enactment behaviors.
- Your loved one appears to be acting out their dreams.
- You or a loved one awakens to find that injuries or damage have been sustained during sleep.
In any of these cases, please consult your physician. The good news? RBD may be treated successfully with clonazepam and melatonin.
You may also wish to safety-proof your sleeping place by padding corners of furniture, installing a bed rail, and putting dangerous items (sharp objects or weapons, in particular) out of easy reach.
Take heart, however; not everyone who experiences RBD goes on to develop PD.
- Hughes, S. Parkinson's Subtypes Predict Prognosis. Available at: https://www.medscape.com/viewarticle/907995. Accessed 3.6.19.