Parasomnias — Sleepwalking, Sleep Terrors, Confusional Arousals & Related Sleep Disorders

The sleepwalking itself is not the primary danger — the person is not conscious and is not in distress. The danger is environmental: sleepwalkers can fall down stairs, leave the house, operate vehicles, or be injured by objects in their path. Bedroom safety precautions (locked doors and windows, removal of trip hazards, a mattress on the floor if falls are a risk, doorway alarms) are the most important management steps. Most sleepwalking resolves spontaneously; medication such as clonazepam or melatonin is considered for frequent episodes with significant injury risk.

The timing and behaviour distinguish the two. Sleep terrors occur in the first 1–2 hours of sleep, from deep slow-wave sleep; the child appears terrified but is not fully awake, cannot be consoled, has no dream to recount when it is over, and has no memory of the event the next morning. Nightmares occur later in the night, from REM sleep; the child wakes fully, is alert, can describe a frightening dream, and may have difficulty returning to sleep. Sleep terrors are alarming to witness but are not harmful to the child and do not require treatment in most cases.

Yes, and this is significantly under-recognised. Apnoeas during slow-wave sleep cause repeated arousals that can trigger NREM parasomnia episodes in susceptible individuals. Adults with new-onset or worsening sleepwalking or sleep terrors should be tested for obstructive sleep apnoea with polysomnography. Treating the OSA with CPAP frequently reduces or eliminates the parasomnia episodes without requiring any other specific treatment.

Video-polysomnography with full EEG is the definitive investigation. Nocturnal frontal lobe epilepsy produces stereotyped, often repetitive movements (bicycling, thrashing, vocalisation) that look similar to parasomnia clinically but are associated with ictal EEG changes on simultaneous recording. NREM parasomnias show characteristic arousal patterns from slow-wave sleep without epileptiform activity. The clinical clues that suggest epilepsy: very short episodes (seconds), high stereotypy (identical movements every episode), multiple episodes per night, and occurring in clusters. The clues that suggest parasomnia: longer episodes (minutes), less stereotyped behaviour, complete amnesia, and first-half-of-night timing.

There is a clear familial tendency, particularly for the NREM parasomnias — sleepwalking and sleep terrors frequently run in families, and a child with one affected parent has a substantially higher likelihood of episodes. In the Indian context, where consanguinity is more prevalent in some communities, multiple affected family members raise the possibility of familial NREM parasomnia. Inheritance does not change the management, which remains safety precautions, trigger avoidance, and treatment of any underlying OSA.

In most cases, yes. Both typically begin in childhood and resolve spontaneously by late adolescence as the proportion of slow-wave sleep falls with maturation. Sleep terrors are most common between ages 3 and 12 and are usually self-limiting. A minority persist into adulthood, and a smaller number have onset in adulthood — the latter group in particular should be assessed for obstructive sleep apnoea and for medication triggers such as zolpidem, since new-onset adult NREM parasomnia usually has a driver that can be treated.