DOCTORS caring for tram crash victim Graham Polak have been given their first chance to assess the football player's brain injury and prospects for rehabilitation after he emerged from a condition known as post-traumatic amnesia this week.

In an exclusive interview with The Age, Polak's doctor, John Olver, said he could assess damage to a patient's brain only when the patient was cleared of the amnesia — a dream-like state that people move into after waking from a coma.

The condition can last between minutes and months depending on the severity of a head injury and is characterised by disorientation, confusion, agitation, fatigue and an inability to store new memories.

"Some people say it's a bit like when you wake up and you're half asleep," Associate Professor Olver, head of the Epworth Hospital's rehabilitation unit, said.

"During PTA, the brain is working at a fairly low level so people generally don't like a lot of stimulation. For that reason we keep them in a very low stimulation environment with lots of nursing care but very little therapy."

He said after a patient passed tests, including recognising memory cards and remembering the date over three consecutive days, they were deemed past the condition and their injury could be assessed.

"At that time, neuropsychologists start testing thinking, speed of thinking, memory, concentration, and whether someone can plan and solve problems … When we know what's working well and what isn't working well, that's when we can start designing rehabilitation."

While Associate Professor Olver would not comment on the specifics of the Polak case, a spokeswoman for Richmond Football Club confirmed the footballer was cleared of amnesia yesterday.

Polak was hit by a tram near his Armadale home on June 29. He was put into an induced coma at The Alfred hospital for two days before being transferred to an Epworth Hospital rehabilitation unit on July 4.

Associate Professor Olver said that after a patient was assessed, it could be weeks and possibly months before the speed of recovery and chances of a full recovery were known.

Because the brain is shaken around against the inside of the skull during head trauma, most people will experience damage to their frontal lobe, he said.

"This is the sort of executive part of the brain that controls emotion, mood, sexuality, and planning … In the long term that can change your personality because it can make you more disinhibited, say inappropriate things and behave in a way that you wouldn't have previously," he said.

Associate Professor Olver said it was impossible to tell at this stage if Polak would regain the skills to return to football.

"Recovery is very individual. I've never seen the same patient twice in 25 years of treating traumatic brain injury," he said.

"In general terms sportsmen are fairly highly motivated though, so that works in their favour in terms of personality.

"But you really can't make any of those predictions soon after an injury, because you just don't know."