A 19-year-old Swedish teenager known to have sleepwalked before was in serious condition after she fell from a fourth-floor flat in Mid-Levels yesterday. The high school student, whom police identified only as Sofie, remained in Queen Mary Hospital last night after undergoing an operation. "The girl suffered a head injury. She was conscious and complained of pain at the scene," a police officer said. The girl suffered a head injury. She was conscious and complained of pain at the scene He said initial investigations found nothing suspicious and the teen did not have suicidal tendencies. Her father told officers she had sleepwalked years ago. Sofie fell from her bedroom window at their home in Pine Court, Old Peak Road, at about 6am while her parents and elder brother were asleep, police said. A neighbour heard a loud bang, found her on the ground outside the building and alerted a security guard. The family was unaware of the incident until the siren of an arriving ambulance woke them. The police officer noted that Sofie's bedroom window was not secured with a grille but it was not known whether the window was open at the time. Officers would talk to her after she had recovered sufficiently. Former Medical Association president Dr Choi Kin said it was rare for sleepwalkers to fall from a height or hurt themselves. "Usually, they can avoid danger even though they are functioning in a state of unconsciousness," Choi said. He said sleepwalking episodes could last from a few minutes to several hours.