Shaken baby trial:'I cannot imagine another way of doing it'

AN expert witness asked how a baby at the centre of a criminal trial could have sustained the catastrophic injuries inflicted on her said he could think of nothing but her being 'severely' shaken, with 'extreme force'.

On a scale of head injuries, from mild to catastrophic, the five-month-old baby girl's head injury was "extremely severe ... catastrophic", Dr Robert Smith said.

The widespread brain injury she presented with on December 12, 2020, had to have involved flexion and torsion, he said, as did the injury to her spinal cord.

Crown prosecutor Jillian Kelton asked what that motion translates to, or looks like, and if it could be a shake.

"I cannot imagine another way of doing it," Dr Smith said.

Dr Smith, a paediatric neurologist and the medical director of the paediatric brain injury rehabilitation team at John Hunter Children's Hospital, was one of the last Crown witnesses in the case against the baby's father.

The 29-year-old man, who can only be identified as GP, has pleaded not guilty to inflicting grievous bodily harm on his daughter.

Dr Smith was also asked, in terms of the severity of "the shake", how severe it would have to have been.

"This had to be very severe, with extreme force," Dr Smith said, in explaining the damage to the spinal cord and surrounding structures.

"The spinal cord is very well protected."

The evidence in the judge alone trial has included a recorded police interview with the accused in which he describes what his daughter was like that morning when he first got her out of bed, before taking her to hospital together with the little girl's mother and older sister.

He told police she "woke up crying, kicked her blankets around".

She had been "normal" that morning, he said. "She was perfect, like ... moving around".

That all changed suddenly, he said, after he changed her nappy and was just about to put clean clothes on her. Her breathing became shallow, and she went limp, he said.

That history, however, did not "conform" to the baby's injuries, Dr Smith said on Tuesday.

"None of that reflects the physical reality of how she presented a short time later," Dr Smith said.

The trial continues.