What characterizes REM sleep behavior disorder?

What characterizes REM sleep behavior disorder?

• A. Loss of normal REM atonia leading to enactment of dreams during REM sleep.
• B. Increased REM atonia preventing movement during REM.
• C. Absence of REM sleep entirely.
• D. Excessive daytime sleepiness with hypnagogic hallucinations.

Answer: (A)

REM sleep behavior disorder occurs when the normal muscle atonia that accompanies REM sleep is lost or reduced. That atonia normally keeps you from acting out dreams, so when it’s impaired you may physically move, speak, or even act out dream content during REM sleep. This is why people with the disorder can kick, punch, or thrash in their sleep, sometimes injuring themselves or a bed partner. Think of the contrast: increasing REM atonia would further suppress movement, not cause it. Skipping REM entirely isn’t the pattern described here, since the person is acting out dreams during REM rather than simply lacking REM. And daytime sleepiness with hypnagogic hallucinations points to narcolepsy, not REM behavior disorder. So the defining feature is loss of REM atonia leading to enactment of dreams during REM sleep.

REM sleep behavior disorder occurs when the normal muscle atonia that accompanies REM sleep is lost or reduced. That atonia normally keeps you from acting out dreams, so when it’s impaired you may physically move, speak, or even act out dream content during REM sleep. This is why people with the disorder can kick, punch, or thrash in their sleep, sometimes injuring themselves or a bed partner.

Think of the contrast: increasing REM atonia would further suppress movement, not cause it. Skipping REM entirely isn’t the pattern described here, since the person is acting out dreams during REM rather than simply lacking REM. And daytime sleepiness with hypnagogic hallucinations points to narcolepsy, not REM behavior disorder.

So the defining feature is loss of REM atonia leading to enactment of dreams during REM sleep.