People with locked-in syndrome are usually completely paralysed, and are unable to speak or move.
- Sufferers can think and reason and can generally move their eyes
- The disorder can follow a traumatic brain injury, such as a massive stroke
- Although there is no cure, therapy such as functional neuromuscular stimulation can sometimes benefit victims by activating some of the paralysed muscles
More top news
The killer serving life for the murder of Jo Yeates has been sentenced to a further 10 months after admitting possessing child abuse images.
Meet the twins from Gloucester who've had to produce their birth certificates to friends in order to prove that they are in fact related.
Sam Galsworthy, uncle of missing Becky Watts, has spoken about the family's anguish as the search for her continues and they wait for news.