The New York Times reports on a firefighter who has made a remarkable and sudden recovery after suffering severe brain injury in 1995.
Donald Herbert sustained a serious head injury when a roof collapsed during a fire fighting operation and has been in hospital since, with his ability to communicate and recognise people severely impaired.
According to news sources, Mr Herbert suddenly started speaking after 10 years, asking to see his wife and other family members.
The recovery has left doctors baffled. So little is known about how the brain repairs and regenerates after injury that it is difficult to predict the course of recovery, although substantial improvement after the first few years of injury are rare.
Some other remarkable cases have been recorded though, including the case of Terry Wallis who regained consciousness after 19 years.