Sleepwalking

Sleepwalking
John Everett Millais, The Somnambulist, 1871
Specialty	Clinical psychology, Psychiatry, sleep medicine

Sleepwalking, also known as somnambulism or noctambulism, is a phenomenon of combined sleep and wakefulness.^[1] It is classified as a sleep disorder belonging to the parasomnia family.^[2] It occurs during slow wave stage of sleep, in a state of low consciousness, with performance of activities that are usually performed during a state of full consciousness. These activities can be as benign as talking, sitting up in bed, walking to a bathroom, consuming food, and cleaning, or as hazardous as cooking, driving a motor vehicle,^[3][4][5] violent gestures and grabbing at hallucinated objects.^[6]

Although sleepwalking cases generally consist of simple, repeated behaviors, there are occasionally reports of people performing complex behaviors while asleep, although their legitimacy is often disputed.^[7] Sleepwalkers often have little or no memory of the incident, as their consciousness has altered into a state in which memories are difficult to recall. Although their eyes are open, their expression is dim and glazed over.^[8] This may last from 30 seconds to 30 minutes.^[6]

Sleepwalking occurs during slow-wave sleep (N3) of non-rapid eye movement sleep (NREM sleep) cycles. It typically occurs within the first third of the night when slow-wave sleep is most prominent.^[8] Usually, it will occur once in a night, if at all.^[6]