A small study in the Sept. 1 issue of the journal Sleep involved the long-term follow-up of 11 people with REM sleep behavior disorder – or RBD.
What is RBD? It is a sleep disorder that causes you to act out vivid dreams as you sleep. Normally your brain paralyzes most muscles during the sleep stage of rapid eye movement (REM) sleep. RBD occurs when the brain fails to keep the muscles still.
Does this excessive muscle activity during sleep increase over time? To find out the researchers from Spain studied nine men and two women with RBD.
The participants were evaluated by two overnight sleep studies: once at diagnosis and again after two to eight years. At follow-up, they had an average age of 73 years; their RBD symptoms had been present for an average of 11 years.
The study measured “tonic” and “phasic” muscle activity during REM sleep. Tonic activity involved sustained muscle tone in the chin; phasic activity involved intermittent muscle twitches of the chin, arms and legs.
Results show that after an average of five years, tonic activity in the chin increased from 30 percent to 54 percent; in two people it was higher than 93 percent. Phasic activity in the chin, arms and legs increased from 38 percent to 59 percent.
The results indicate that RBD involves a progressive dysfunction of the brain structures that suppress muscle activity during REM sleep. A greater extent of brainstem impairment may occur over time.
The authors suggest that RBD may represent an early stage of a neurodegenerative disease. Many people with RBD go on to develop other neurologic diseases; these include Parkinson’s disease, dementia with Lewy bodies and multiple system atrophy.
In June the Sleep Education Blog reported that there are effective treatment options for people with RBD. Contact an AASM-accredited sleep center if you or someone you know acts out dreams during sleep.