Parasomnias (also known as disorders of arousal) are a group of sleep disorders characterized by abnormal behavioral, experiential, or physiological events occurring in association with sleep, specific sleep stages, or sleep-wake transitions.
The most common parasomnias are the group of non-rapid eye movement (NREM) sleep arousal disorders and rapid eye movement (REM) sleep behavior disorder. These conditions serve as a reminder that sleep and wakefulness are not mutually exclusive and that sleep is not necessarily a global, whole-brain phenomenon.
Some key questions can be asked to screen for parasomnias:
REM
ember events (i.e. - no confusion, no amnesia) in REM parasomnias!
Parasomnia Type | Stage of Arousal | Time of Night | EEG during event | EMG during event | Unresponsive during event | Autonomic activity | Anmesia | Confusion post-episode | Family history of parasomnias | |
---|---|---|---|---|---|---|---|---|---|---|
Confusional Arousal | NREM | NREM Stage 2-4 | Anytime | N/A | Low | Yes | Low | Yes | Yes | Yes |
Sleepwalking | NREM | NREM Stage 3-4 | First 2 hours | Mixed | Low | Yes | Low | Yes | Yes | Yes |
Sleep terrors | NREM | NREM Stage 3-4 | First 2 hours | Mixed | Low | Yes | High | Yes | Yes | Yes |
REM sleep behaviour disorder | REM | REM | Anytime (but more likely later half) | Characteristic of REM | High | Yes | High | No | No (can remember the dreams!) | No |
Nightmare disorder | REM | REM | Anytime | N/A | N/A | Yes | High | No | No (can remember the dreams!) | No |
Brief arousals from SWS is suggestive of parasomnias (think: the brain is fast asleep, but muscles and other movements are occurring and this showing on PSG).