If you or a loved one have ever acted out dreams while remaining asleep, it could be a condition known as REM behavior disorder.
Defining REM Behavior Disorder
During the night, we naturally progress through sleep stages, including rapid eye movement (REM) sleep. REM is normally characterized by intense brain activity and dreaming -- and the inability to use our muscles, with the exception of our eye muscles and diaphragm (which allows us to breathe).
If our other muscles are not properly paralyzed, we may be able to perform complex activities and enact our dreams while we remain asleep. This is called REM behavior disorder. This disorder may lead to accidental injury, including injury of bed partners.
Symptoms of REM Behavior Disorder
Most people with this disorder describe unpleasant and vivid dreams that involve intruders or attackers (people or animals). There is associated dream-enactment behavior that is often violent. Common behaviors include:
- Talking or screaming
- Jumping or falling out of bed
- Striking furniture
These behaviors frequently result in injury to the individual or their bed partner. The injuries may be minor (such as bruises or cuts) or severe (such as broken bones or bleeding within the brain). People who are afflicted may complain of disrupted sleep or excessive daytime sleepiness.
REM behavior disorder affects about four or five people out of every 1,000. In about 90% of cases, it occurs in men who are in their 50s or 60s.
Getting a Diagnosis
In most cases, a reported history of dream-enactment behaviors with a polysomnogram (PSG) will be sufficient to establish a diagnosis. The PSG will often show the abnormal presence of muscle tone during REM sleep, suggesting the ability to inappropriately act out dreams. It is also important to document an absence of seizure-like electrical activity on the EEG because seizures can sometimes cause abnormal movements during sleep.
Imaging studies are typically normal in REM behavior disorder if there is no associated neurodegenerative disorder. However, the condition commonly occurs in the setting of other disorders.