Sleepwalking: Purposeful moving, usually but not always including walking, while in a deep stage of sleep. Sleepwalking occurs most frequently in children, particularly boys. Sedatives tend to exacerbate rather than cure sleepwalking. The best measures are preventive: Ensure that the sleepwalker is in a safe room for walking and cannot accidentally fall through an open window or down stairs. Some types of sleepwalking are related to seizure disorders, bipolar disorders, and other neurological conditions, but most cases are transitory and due to unknown causes. Also known as somnambulism.