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.