A MAN who was barely conscious for nearly 20 years regained speech and movement because his brain spontaneously rewired itself, growing tiny new nerve connections to replace the ones sheared apart in a car crash, doctors say they now can prove.
The man, Terry Wallis, 42, from Arkansas, is thought to be the only person in the United States to recover so dramatically so long after a severe brain injury.
Although his progress is exciting and inspiring, doctors said the same cannot be hoped for people in a persistent vegetative state. Nor do they know how to make others with less serious damage recover, as Mr Wallis did.
The results were published in the Journal of Clinical Investigation.
Mr Wallis was 19 when an accident gave him a brain injury that left him briefly in a coma and then in a minimally conscious state, in which he was awake but uncommunicative other than occasional nods and grunts, for more than 19 years.
"The nerve fibres from the cells were severed, but the cells themselves remained intact," said Dr James Bernat, a neurologist at Dartmouth-Hitchcock Medical Centre.
Nerve cells that have not died can form new connections; for example, nerves in the arms and legs can grow about an inch a month after they are severed or damaged. However, this happens far less often in the brain.
The research suggests that instead of the sudden recovery Mr Wallis seemed to make when he began speaking and moving three years ago, he actually may have been slowly recovering all along, as nerves in his brain formed new connections at a glacial pace until enough were present to make a network.