REM Sleep Behavior Disorder is described by

• A. It features normal REM sleep muscle atonia.
• B. People act out dreams due to loss of REM sleep muscle atonia.
• C. It occurs only in older adults.
• D. It never involves dream content.

Answer: (B)

REM sleep behavior disorder arises from loss of REM sleep muscle atonia, which normally keeps us still during dreams. When this atonia is absent or incomplete, the motor system isn’t properly inhibited, so dream content is acted out in real life—punching, kicking, talking, or even leaving the bed. This is why the statement that people act out dreams due to loss of REM sleep muscle atonia is the best description. Dream content is typically vivid and meaningful to the person, and movements can be complex and potentially injurious to the individual or a bed partner. The condition is more common in older adults and can be idiopathic or associated with neurodegenerative processes like synucleinopathies. Diagnosis often involves sleep study findings of REM sleep without atonia, and management focuses on safety, with melatonin as a common first-line treatment and sometimes clonazepam.