Ep 227 – Parasomnia

In this episode, Dr Roger Henderson explores a fascinating and sometimes unsettling area of clinical practice: parasomnias. Sleep is something everyone experiences, but for some patients it is far from quiet or predictable: they may walk, shout, experience vivid nightmares or even physically act out their dreams, leaving both them and their partners confused, frightened or concerned about what these behaviours might mean. For GPs, recognising the pattern is crucial. Is the episode occurring early or late in the night? Is the patient confused or fully alert afterwards? Do they remember what happened, and could medication, another sleep disorder or an underlying neurological condition be contributing? Here, we cover the key clinical features of non-rapid eye movement (NREM) parasomnias, nightmare disorder and rapid eye movement (REM) sleep behaviour disorder, and discuss practical approaches to their assessment, differential diagnosis and management.

Key take-home points

• Parasomnias are abnormal behaviours, movements or experiences that occur during sleep or during transitions between sleep and wakefulness.
• Timing is a valuable diagnostic clue: NREM parasomnias generally occur earlier in the night, while REM-related events tend to occur later.
• Sleepwalking is an NREM arousal disorder, typically occurring during the first part of the night, with limited awareness and little or no recall the following morning.
• Sleepwalking is particularly common in children and often resolves as they get older.
• Sleep terrors involve abrupt arousal, intense fear, screaming, and motor activity, usually followed by confusion and amnesia for the event.
• Nightmares differ from NREM parasomnias because the patient usually wakes fully oriented and can recall the distressing dream. They typically occur during the latter part of the night.
• REM sleep behaviour disorder occurs when the normal muscle atonia of REM sleep is lost, allowing patients to physically or vocally enact their dreams.
• Dream enactment can result in significant injury to the patient or bed partner, making assessment of the sleeping environment an important part of management.
• REM sleep behaviour disorder has an important association with neurodegenerative disorders, including Parkinson's disease, dementia with Lewy bodies and multiple system atrophy.
• The bed partner or another witness can provide crucial information because patients may have little awareness or recollection of their night-time behaviours.
• A thorough assessment should include sleep history, medical and psychiatric history, medication use and a sleep diary; snoring, breathing difficulties and limb movements should also be explored.
• Several medications have been reported to precipitate or worsen parasomnias, so a medication review is an essential part of the assessment.
• A simple framework – the timing of the episode, the patient’s level of awareness and their memory of the event – can help distinguish between NREM arousal disorders, nightmare disorder and REM sleep behaviour disorder.
• New-onset sleepwalking in an adult warrants particular attention, including consideration of nocturnal seizures, sleep-related breathing disorders and medication effects.
• Management should address potential triggers and safety, with pharmacological and non-pharmacological treatments selected according to the specific parasomnia and clinical context.

Key references

1. Singh S, et al. Cureus. 2018;10(12):e3807. doi: 10.7759/cureus.3807.
2. Bollu PC, et al. Mo Med. 2018;115(2):169-175.
3. Aurora RN, et al. J Clin Sleep Med. 2010;6(1):85-95.
4. Galbiati A, et al. Behav Neurol. 2015;2015:786928. doi: 10.1155/2015/786928.
5. Boeve BF. Ann N Y Acad Sci. 2010;1184:15-54. doi: 10.1111/j.1749-6632.2009.05115.x.