The trial of a woman charged with killing her seven-year-old daughter in 2018 heard from a defence witness who pointed to a pre-existing brain condition that he said might have contributed to the girl’s death.

On Monday, March 29, Dr. Christopher Dunham testified that he believed Aaliyah Rosa may have had “arrested hydrocephalus,” a swollen brain, but without the obvious symptoms such as headache or nausea.

“There was no obvious neurological history, so it’s possible to the layman she was not having any symptoms,” he said.

A blow to the head could have been enough to “tip the equilibrium” causing further swelling, cutting off blood flow to the brain and causing death, testified Dunham, who is a pediatric neuropathologist at B.C. Children’s Hospital.

Aaliyah was seven years old when her body was discovered in the apartment of her mother, Lewis, in Langley on July 22, 2018.

Lewis was charged with first degree murder.

The trial has already heard evidence including toxicology tests showing that Aaliyah’s bloodstream contained Benadryl and prescription tranquilizer Ativan at the time of her death.

The girl’s body was discovered when Lewis’s ex-boyfriend tried to return to the apartment, and found the door partially barricaded by boxes.

The trial has also heard witnesses who said Lewis had spoken of wanting to die with her daughter because of frustration over her lack of custody access.

The Crown’s claim is that Lewis drowned Aaliyah after sedating the girl. She was found next to a full bath tub in the bathroom of Lewis’ Willoughby apartment.

Questioned by defence lawyer Marilyn Sandford, Dunham said there can be a number of causes of hydrocephalus.

“In this case it appears to be a congenital malformation.”

Dr. Lisa Steele, the pathologist who conducted the autopsy on Aaliyah, said the young girl died of an acute lack of oxygen.

READ MORE: Langley child murder trial delayed until March as new witness testifies

READ MORE: Lack of oxygen killed Langley seven year old, pathologist testifies

Steele said there had been some kind of head injury, which could have caused brain swelling and bleeding inside her skull.

Dunham agreed that there had been blows to the head.

“In this case, we know that there’s blunt force trauma,” Dunham testified. “That’s likely one contributor to the edema [swelling] in this case.”

“We don’t know what caused the head injury to occur,” he later said. But he said the blunt force trauma could have caused death combined with the hydrocephalus.

The trial has taken months longer than was expected, after multiple delays last fall caused by COVID-19. Several witnesses either contracted COVID or were exposed to it, delaying their testimony. Lewis’ own health issues also caused delays. At one point, she collapsed with a thud in the courtroom.

Due to busy court schedules, the trial was paused in January until lawyers, judge, and Dunham were all available to resume the hearing on Monday, March 29.

The trial is expected to resume Wednesday morning.

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