REM sleep behavior disorder is a parasomnia characterized by episodes of vigorous motor activity (like punching, kicking, or crying out) and vocalizations during REM sleep. In REM sleep behavior disorder, the mechanisms that disable motor activity during sleep don’t function normally, so movements aren’t inhibited during sleep. REM sleep behavior disorder occurs during sleep, not during an arousal from sleep.
People with REM sleep behavior rarely act out mild dreams; rather, the dreams acted out tend to be violent and intense, making this one of the more dangerous sleep disorders.
Symptoms of REM Behavior Disorder
Gross motor activity during sleep, like walking, kicking, running, punching and jumping
Talking or yelling during sleep
Feeling alert and aware upon awakening
Memory of the episode afterward, sometimes for months
How Common is REM Behavior Disorder?
Unlike other parasomnias, which are more common in children and usually outgrown, REM sleep behavior disorder is most common in older adults. The disorder usually begins between age 50 and 60, and is more common in men. REM sleep behavior disorder with violence is rare, occurring in around .05 percent of the adult population.
Although the vast majority of patients with RBD are older men, women and children as young as 10 years old have been diagnosed. Estimated prevalence in adults of 0.4-0.5 percent . In a recent comparison study of the prevalence of parasomnias among a population of patients with diagnosed sleep disorders, REM sleep behavior disorder was found to be the least common with a frequency of 4.8 percent.
What Causes REM Behavior Disorder?
In REM behavior disorder, the normal suspension of motor activity during sleep (called sleep atonia) doesn’t occur, allowing people to act out their dreams. However, the dreams acted out are often violent and frightening, even if this is out of character for the person experiencing RBD.
RBD can be idiopathic (no known cause) or it can be a symptom an underlying disorder or neurodegenerative disorder. Studies have found that about half the time, RBD has no discernable underlying cause. The other half of the time, people with RBD have a related neurological condition.
REM behavior disorder is linked to Parkinson’s Disease and Lewy Body Dementia, and can precede the development of these disorders by 5 to 10 years. The likelihood of developing a neurodegenerative disease following up to 5 years of the RDB diagnosis is between 30 – 45 percent, according to recent studies .One researcher suggested that curing REM behavior disorder could be a way to prevent development of Parkinson’s Disease.
Other conditions linked to REM behavior disorder include include:
Brain stem lesions
Tumors (both benign and cancerous)
A study of hundreds of idiopathic RBD patients published in the journal Neurology in 2012 concluded that head injuries, pesticide exposure, and smoking are risk factors for REM behavior disorder. Animal research has indicated that the GABA-A and GABA-B systems are part of what causes skeletal muscle paralysis in REM. By blocking molecular receptors, researchers were able to produce mice that demonstrate RBD symptoms.
Some studies suggest that antidepressant SSRI drugs may aggravate REM behavior disorder; these medications are known to impact REM sleep.
Doctors diagnose REM behavior disorder by reviewing medical history and symptoms. Your physician may conduct a physical and neurological examination to determine whether you have an underlying sleep disorder or health condition. In some cases, a polysomnogram, or overnight sleep study, may be performed to evaluate heart, brain and lung activity during sleep.
People with RBD who know about their behavior sometimes develop hypnophobia, especially when others are around (house guests) and they fear embarrassment. Environmental modifications, including barriers around the bed, are sometimes used to treat RBD. Some people use physical constraints, like sleeping in sleeping bags or wearing oven mitts during sleep.
When RBD poses are risk to the sleeper or causes severe sleep disturbance, doctors may recommend medications. These include the benzodiazepine anticonvulsant Klonopin (clonazepam), melatonin, and dopamine agonists used to treat Parkinson’s Disease.