Evidence of Nia's aunt expected to point to time of toddler's injury

Nia Glassie's aunt is expected to tell a jury today that she decided to take her unconscious niece to hospital after seeing her grind her teeth and clench her jaw to the point that she could not prise the toddler's teeth apart.

Yesterday, Louise Kuka told the High Court at Rotorua that Nia - who she nicknamed Mamma after the Abba song Mamma Mia - had been "her normal self" on the evening of July 20 last year.

Ms Kuka said she had been at Nia's house and left just before 7pm, and though the 3-year-old was not talkative for the two hours she was there, she had no concerns for her wellbeing.

The Crown alleges brothers Wiremu and Michael Curtis kicked Nia in the head some time between about 7.30pm and 8pm, sending her into a coma from which she never emerged.

Nia was admitted to Rotorua Hospital on July 22 and died in Auckland's Starship 12 days later.

A pathologist told the court she had a blood clot in her head that was between 10 and 14 days old when she died.

Dr Simon Stables said the clot was the result of trauma and led to brain swelling, which in turn caused Nia's brain to die.

He said blows to the head and falls from a height were usual causes of such injuries, which were common among boxers who received blows to the head and hit the ground.

Dr Stables performed an autopsy on Nia the day after she died and said "a substantial degree of force", possibly a kick, had caused the injury to her head.

He also found five bruises under her scalp but no fractures and no notable external injuries.

He ruled out natural causes, and said the type of injury to the toddler's head usually resulted in a quick decline in children, sending them into a coma in as little as 10 minutes.

"In essence, what this child has had is a huge stroke."

He said the symptoms of coma in a child Nia's age included appearing asleep, fits, incontinence, and frothing at the mouth - all of which earlier witnesses said were symptoms Nia displayed on July 21.

Dr Stables believed that Nia had received the head injury on July 20 because, from what he had been told, she had been acting relatively normally before then.

But under cross-examination, the pathologist acknowledged she could have been injured two days earlier when she was allegedly spun on a clothesline until she fell off and hit the ground.

Forensic neuropathologist Beth Synek dated the age of the head injury as "10 days plus".