Neurosurgeon Dr Michael du Trevou, during cross-examination by prosecutor Susan Galloway, said it was impossible to exclude malingering.

He also conceded that losing consciousness for two hours and 40 minutes, and recovering on one’s own, was unlikely but that a post-traumatic amnesiac period was possible.

Photos of Van Breda after the 2015 attack on his family were also analysed. Du Trevou pointed out his black eye and some bruising under both his eyes.

The injuries were not severe, he said, but brain injury could be without bruising and may not translate to head injuries.

Traumatic brain injuries

In his report, Du Trevou said all retrograde and post-traumatic amnesia was a gesture of traumatic brain injuries, including concussion.

This could last minutes to days, he explained, depending on the severity of the impact.

Normal activity is possible, but the person may have no recollection of these activities, and the loss of memory is usually permanent.

Du Trevou found that a loss of consciousness lasting two hours and 40 minutes after a head injury was an indication of a mild to moderately severe traumatic brain injury.

"It is not possible to determine, ex-post facto, whether the accused had lost consciousness or whether he merely lost recall of the incident," he said in his report.

"The mere fact that no evidence of a prior injury is visible on the MRI scans does not exclude the possibility that he had lost consciousness or recall of the events subsequent to hitting his head."

Van Breda, 22, pleaded not guilty to axing his parents and brother to death, seriously injuring his sister Marli and defeating the ends of justice.

He alleged that an intruder wearing a balaclava, gloves and dark clothes was behind the attack, and that he had heard other voices of people speaking Afrikaans in their home in the De Zalze Estate in Stellenbosch in January 2015.

Van Breda claimed that, after a fight with the axe-wielding intruder who was also armed with a knife, the man had fled down the stairs and that he threw the axe at the attacker.

He ostensibly fell down the stairs in the process.

Van Breda claimed to have reached for his phone, which was in his pocket, and tried to call for help, but did not have numbers for emergency services. His girlfriend did not answer when he called her.

While making his way upstairs, he Googled emergency services. On his way up, he saw Rudi and Marli moving. Teresa was not moving.

Lying on the stairs

He later woke up lying on the stairs. He was not sure how long he had been there for, but it has since been confirmed to be two hours and 40 minutes.

The neurosurgeon said passing out for this period was consistent with mild head injury.

Du Trevou’s findings were based in part on Van Breda’s plea explanation, which was not evidence before court. Van Breda has not testified.

Judge Siraj Desai pointed out it would be seen as hearsay evidence.

Du Trevou had never examined or met Van Breda, and was asked to "comment blindly", as Galloway put it.

Loss of consciousness

He explained that among the causes of loss of consciousness were medical conditions, drug use, certain medications and alcohol use.

Advocate Pieter Botha, for the defence, pointed out that Van Breda’s blood had tested "clean" that night.

Du Trevou said a vasovagal attack - when one faints because the body overreacts to certain triggers, such as the sight of blood or extreme emotional distress – was also possible. The person, however, feels better once horizontal, Du Trevou explained, except if Van Breda possibly fell and bumped his head.

Dr Michelle van Zyl from Vergelegen Mediclinic saw Henri twice on January 27, 2015 - when he asked for one of his stab wounds to be examined for possible stitches.

He was accompanied by police who informed her he was a suspect in a murder investigation.

During his first visit, Henri’s emotional status was noted as confident, not emotional, and she detected a slight smell of alcohol on his breath, she had testified.

Galloway pointed out that Van Zyl had said during their first meeting they "had a nice conversation", and that she had treated his wound with clips.

There was no indication of head injury, she recalled.

Du Trevou said it was common that an injured person appeared normal.

The trial resumes on Tuesday when a new witness will be called.

News24