During which sleep stage does sleepwalking most likely occur?

Sleepwalking primarily occurs during Stage 3 NREM sleep, also referred to as slow-wave sleep or deep sleep. This stage is characterized by the presence of slow delta waves on an EEG and is the deepest phase of non-rapid eye movement sleep. During this time, the body is in a state of physical restoration, and brain activity slows significantly. Because the individual is in a deeper stage of sleep, it is possible for them to rise and walk around without being fully aware or conscious of their actions, which is the hallmark of sleepwalking.

In contrast, REM sleep is associated with vivid dreaming and increased brain activity, making it less likely for sleepwalking to occur. The lighter stages of NREM sleep, such as Stage 1 and Stage 2, are not typically associated with sleepwalking either, as they do not reach the depth of sleep necessary for such complex behaviors. Therefore, the likelihood of sleepwalking is notably higher in Stage 3 NREM sleep, which is why it is considered the correct answer.