Oscar Pistorius trial hears of amputee 'stress and anxiety'
South African double amputee Oscar Pistorius has been greatly affected by his disability, a sports doctor has told his murder trial in Pretoria.
Defence witness Wayne Derman told the court that the Paralympian suffered "significant stress and anxiety".
Mr Pistorius says he shot his girlfriend Reeva Steenkamp after mistaking her for an intruder in their house last year.
The prosecution argues that he killed her deliberately after a row.
At issue is the athlete's state of mind at the time of the shooting.
On Monday, the court heard he was not suffering from a mental disorder when he shot Ms Steenkamp.
According to a psychiatrists' report, Mr Pistorius, 27, is capable of distinguishing between right and wrong and so should bear criminal responsibility for his actions.
The court also heard a psychologist's assessment on Wednesday which found that he had post-traumatic stress disorder since the shooting and could be a suicide risk.
It found he was mourning Ms Steenkamp, 29, a model and law graduate.
'Disability never sleeps'
The athlete's lawyer, Barry Roux, has argued that his client would react more sharply to fear than an able-bodied person would because of the anxiety caused by his disability.
Mr Derman, a professor of sports and exercise medicine at the University of Cape Town, was the final witness called by the defence. He has worked with South Africa's Olympic and Paralympic teams.
He said Mr Pistorius had had a "lifetime of real and learnt vulnerability" as a result of his disability. Disability, he said, had a "knock-on" effect through one's entire life. "Disability never sleeps."
The athlete, the professor added, also had a "profound fear of crime".
The athlete, he said, had developed an "exaggerated fight response" and this was responsible for the "horrific tragedy" of Ms Steenkamp's death.
But cross-examining Mr Derman, prosecutor Gerrie Nel suggested Mr Derman's statements amounted to "character" rather than "expert" evidence.
Analysis: Pumza Fihlani in Pretoria
The theory of the "two Oscars" came into sharp focus in court as sports doctor Wayne Derman spent a second day on the stand.
He described the athlete's battle with his life, a paradox of supreme ability and great disability.
Dr Derman said due to his disability, to fight was his only alternative when he believed there was an intruder in the house.
But prosecutor Gerrie Nel accused Dr Derman of being biased in favour of Mr Pistorius, of whom he said he had an "intimate knowledge".
Much time was spent on the timings of his response and actions leading up to the moment he shot his girlfriend.
Mr Nel tried to find enough room in Dr Derman's testimony to show that the accused had enough time to think of his actions.
One of the most difficult questions the defence needs to answer in this trial is why Mr Pistorius fired through a closed toilet door. The answer to that will decide Mr Pistorius's fate.
Mr Pistorius says he fired multiple shots into a toilet cubicle where Ms Steenkamp was, while in a state of panic.
The sprinter and Ms Steenkamp had been dating for about three months before the shooting.
Mr Pistorius said in his statement at the start of the trial that he woke in the early hours and walked on his stumps to the balcony, pulled in two fans, closed the sliding door and drew curtains. He said that shortly before he had spoken to Reeva, who was in bed beside him.
He said he rejected prosecution claims that a witness heard arguing coming from the house before the shooting.
2. Bathroom window×
Mr Pistorius said he heard the bathroom window sliding open and believed that an intruder, or intruders, had entered the bathroom through a window which was not fitted with burglar bars.
"Unbeknown to me, Reeva must have gone to the toilet in the bathroom at the time I brought in the fans," he said.
Mr Pistorius said he approached the bathroom armed with his firearm, to defend himself and his girlfriend, believing Ms Steenkamp was still in bed.
Both sides agree four bullets were fired. Ms Steenkamp was hit three times.
Mr Pistorius said he fired his weapon after hearing a noise in the toilet which he thought was the intruder coming out of the toilet to attack him and Ms Steenkamp.
He said he was in a fearful state, knowing he was on his stumps and unable to run away or properly defend himself.
Mr Pistorius said he rejected claims that he was on his prostheses when he shot at the door.
A witness told the trial she woke to hear a woman screaming and a man shouting for help. She said that after the screams she heard four shots.
Mr Pistorius said he went back to the bedroom after shooting at the toilet door, still shouting for Reeva. Lifting himself up onto the bed, he felt over to the right hand side of it and noticed Ms Steenkamp was not there.
Mr Pistorius said this was when he realised she could have been in the toilet.
5. Toilet door×
Mr Pistorius said he went back to the bathroom but the toilet was locked, so he returned to the bedroom, pulled on his prosthetic legs, turned on the lights before bashing in the toilet door with a cricket bat.
Forensics expert Johannes Vermeulen told the court that the height of the marks on the door caused by the cricket bat suggest Mr Pistorius was on his stumps at the time.
6. Emergency calls×
Mr Pistorius's defence team say he then called security at the gated housing complex and a private paramedic service before carrying Ms Steenkamp downstairs.
A security guard claimed it was the other way round, and he had called Mr Pistorius first after reports of gunfire. However, phone records shown to the court revealed Mr Pistorius called the estate manager at 3:19am, a minute later he called the ambulance service and at 3:21am he called estate security.
A minute later he received an incoming call - estate security calling him back.
According to police phone expert Francois Moller, Mr Pistorius called his friend Justin Divaris a short time later and just after 4:00am he called his brother Carl.
He has often displayed his emotions during the trial, including breaking down in tears in court.
There are no juries at trials in South Africa, so the athlete's fate will ultimately be decided by the judge, assisted by two assessors.
If found guilty of murder, Mr Pistorius, who went on trial on 3 March, could face life imprisonment. If he is acquitted of that charge, the court will consider an alternative charge of culpable homicide, for which he could - if convicted - receive about 15 years in prison.
The court has been adjourned until Monday.