Experts stand by shaken baby theory in babysitter trial

By Sue Yanagisawa
Local News - Tuesday, September 28, 2004 @ 07:00

The main weakness in scientific calculations purporting to challenge the mechanics of shaken baby syndrome is that researchers can’t replicate the complexities of a human brain, an expert testified yesterday.

Dr. Jean Michaud, a professor of neuropathology at the University of Ottawa and chairman of neuropathology and laboratory medicine at Ottawa Hospital and the Children’s Hospital of Eastern Ontario, gave evidence yesterday at the manslaughter trial of Cheryl Ann Larsen, 33.

Larsen is accused of causing the death of 22-month-old Brody Albert in December 2002 – allegedly by shaking him so violently that his brain was injured. She has pleaded not guilty.

A mother of three young boys, Larsen was babysitting Brody for about an hour on Dec. 6, 2002, when she called 911. Paramedics arrived to find the toddler unconscious and were told the boy had fallen down a carpeted flight of steps into the finished basement of Larsen’s Pembridge Drive home.

However, a series of doctors who became involved in his case, including Michaud and Dr. Blair Carpenter – the pediatric pathologist who conducted Brody’s autopsy and who also testified yesterday – all diagnosed his injuries as consistent with shaken baby syndrome.

Lawyer Peter Kemp, who’s part of Larsen’s defence team, has grilled all the Crown’s medical experts, confronting them with opposing opinions based on biomechanics. He has, in effect, put their diagnosis on trial, suggesting that there’s substantial doubt outside the medical community that shaken baby syndrome is scientifically provable.

Michaud admitted “there are controversies in this area, because we’re dealing only with the outcome.”

He rejected Kemp’s suggestion that doctors don’t accept the conclusions of investigators in the field of biomechanics because they don’t understand the physics.

He told Kemp that definitive “biomechanical research is impossible to do, [because] you cannot reproduce a brain.”

He told Superior Court Justice Helen MacLeod that investigators trying to model what happens inside a child’s head during a fall or shaking must of necessity use either mechanical models, which fail to replicate the complexities of living brain tissues, or animal surrogates with different physiology and patterns of development.

While their findings may feed their own doubts, “I do not believe this will eliminate the good clinical judgment of generations of surgeons,” he told the court.

“In 30 years,” he insisted, “I’ve never done an autopsy following a domestic fall” of the sort he was told Brody suffered.

Kemp has asked each of the doctors why, if Brody was shaken violently, the only external evidence of damage was a small swelling on the back of his head. There were no bruises on his body, indicative of being held tightly, rib fractures or damage to his neck, consistent with a whiplash-type injury.

So far, the doctors have been unanimous in their opinion that bruises and broken bones – while frequently present in shaken babies – aren’t always present.

The pediatric pathologist, Dr. Carpenter, testified that children seldom suffer whiplash neck injuries in car accidents and even adults who receive fatal brain injury in collisions “don’t always have a cervical lesion that can be seen on autopsy.”

Kemp asked Carpenter if it was possible that Brody’s brain injury could have been caused by falling backwards down a flight of stairs. The pathologist agreed that, depending on how the boy fell, “it’s clinically possible [but] I personally don’t think so.

“Anything is possible, but not likely.”

The theory behind shaken baby syndrome, as it’s been explained in court, is that violently shaking a very young child causes a damaging rotation inside his skull. The resulting movement appears to shear and tear delicate blood vessels and the bleeding that results can either kill the child or leave permanent damage.

All the doctors have testified that in making their diagnosis they’ve relied on a variety of features, including: the bleeding inside Brody’s skull; distinctive patterns of bleeding in the deep structures of his eyes; microscopic changes and damage to nerve fibres in his brain; and an oral explanation for the damage at odds with their clinical experience and the medical literature.

“I just have a hard time accepting all that [damage] was due to a minor fall or a minor impact, by the child,” Carpenter told Kemp, referring to Brody’s case.

Even with a hard fall down stairs, Carpenter and several of the doctors testified that if there had been a brain injury they would expect to see a more linear pattern to the damage.

“That rotation [of his brain] has not been explained to me, that’s all I’m saying,” Carpenter told Kemp.

Kemp cited one study to the doctor in which volunteers were asked to violently shake a weight about the equivalent to that of a toddler, or about 23 pounds. Researchers reported that all of the women in the study and many of the men reported severe fatigue after about 10 seconds.

Carpenter noted that all of the volunteers would’ve been average people, however, and told Kemp that in shaken baby syndrome “some people have postulated there is a form of rage or frenzy.”

Michaud also allowed that it’s possible Brody could have acquired his injuries in an accidental fall.

“But you would have to have a very reliable history,” to make that finding, he told Kemp.

And in 30 years of practice, he said he’s never seen or heard of a fall duplicating the injuries he found in Brody’s brain.