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UC
Berkeley expert on head impacts sets out to change way society deals with
possible shaken baby syndrome
27
November 2001
By
Robert Sanders, Media Relations
Berkeley
- Mechanical engineer Werner Goldsmith of the University of California,
Berkeley, is on a mission to reform the way doctors and prosecutors view
the thousands of suspected cases of shaken baby syndrome each year.
An often fatal set of
symptoms caused by violent shaking of an infant or young child, shaken baby
syndrome can be difficult to diagnose because frequently there are no
external signs of abuse. Most of the damage is in the brain.
Backed by decades of
research on the effects of head impacts, and as author of the only book on
the subject of impacts, Goldsmith nevertheless sees a rush by
pediatricians, social workers and prosecutors to brand many parents and
caregivers as child abusers when the injuries were more likely caused by a
fall.
"Anyone who
abuses a child deserves the full fury of the law," said Goldsmith, a
professor of the graduate school at UC Berkeley. "But people should
know the truth. The brain injuries that lead many prosecutors to file
charges of child abuse can also be caused by falls or even result from
chronic bleeding in the brain."
To get his message
out, Goldsmith is traveling around the country educating the medical
community as well as lawyers and child welfare caseworkers about the
complexities of establishing a cause of child brain damage. He also
counsels numerous lawyers and testifies as an expert on head impacts at
trials, where he sees first-hand the rush to judgement.
"A child in
someone's care dies by natural causes or accident and the district attorney
files charges claiming shaken baby syndrome," he said. "Suddenly,
the caregiver is faced with life in prison."
His message to
doctors and lawyers is not to assume that a child with bleeding in the
brain and the eye is automatically the victim of child abuse. Doctors
typically look for these symptoms, called subdural hematoma and retinal
hemorrhage, respectively, plus brain swelling or edema.
Such symptoms could
result from an accident or, under certain circumstances, from a chronic
condition. Doctors and medical examines need to look for other signs of
abuse, in particular, neck damage, he argues.
"I am absolutely
convinced that in order to do serious or fatal damage to an infant by
shaking you have to have soft tissue neck damage," Goldsmith said.
"Yet, in 95 percent of cases, medical examiners do not look at the
neck in autopsy. They look at the stomach, the abdomen, the head, but the
neck is neglected."
The main problem is
that very little research has been done on the effects of head impacts in
infants and small children. Goldsmith, whose 1960 book, "Impact: The
theory and physical behaviour of colliding solids," will be reissued
next month by Dover Publishers, has written more than 50 papers on the
biomechanics of head and neck injury. Yet, though he pioneered the
application of biomechanics to head injury, he has conducted no studies of
infants. Only one such study has been done, in 1987, and that employed a
doll whose head was stuffed with wet rags.
To remedy this lack
of basic data, within a few months he plans to embark on a preliminary
study with UCSF neurosurgeon Geoffrey Manley, MD, PhD, using professional
crash test dummies instrumented with devices to measure the types of forces
an infant would sustain during shaking and other types of abuse.
"I have a very
strong feeling that, given how little we really know about the mechanical
issues involved in head injury, there may be people who are convicted of
crimes they are not guilty of," said Manley, chief of neurotrauma at
UCSF.
For now, Goldsmith
hopes to make an impact on the overly aggressive approach of many
pediatricians to suspected shaken baby syndrome.
Though most doctors
look for brain edema, subdural hematoma and retinal hemorrhaging, many
other types of trauma produce similar symptoms, he said. In fact, bleeding
in the brain normally increases pressure, leading to swelling and retinal
bleeding. So anything that causes intracranial bleeding, in particular
falls, can display this trio of symptoms.
A fall backwards from
three feet onto a hard surface, like concrete, can produce nearly 180 Gs of
acceleration - 180 times the force of Earth's gravity - enough to cause a
subdural hematoma, Goldsmith calculated. Shaking a child once a second
through a range of one foot produces only 11 Gs, at the most.
"There is an
order of magnitude difference between shaking and falling," Goldsmith
said. "From the point of view of the brain, shaking is a much, much
milder form of braking than a fall."
One dogma often
espoused by doctors is that short distance falls do not cause serious harm.
However, videotapes demonstrate that falls from as little as 32 inches can
cause fatal brain damage in infants and toddlers.
To complicate
matters, between 5 and 10 percent of children are born with undiagnosed
subdural hematomas, and 30 percent are born with retinal bleeding,
Goldsmith said.
"If you get a
rebleed, you may get something that looks like shaken baby syndrome,"
he said.
Because of such
uncertainties, Goldsmith urges physicians and prosecutors to look for more
certain evidence of shaking, specifically damage to the neck.
"You should be
able to show neck damage to prove shaken baby syndrome," he said.
Goldsmith also urges
doctors to talk to biomechanical engineers to get an understanding of the
forces involved in accidental falls versus child abuse.
The ultimate goal of
Goldsmith and Manley is to build a sufficiently lifelike baby dummy
containing a skull, dura (a tough membrane that lines the skull and
envelops the brain) and brain whose properties are very similar to the real
thing. The dummy studies planned for January will provide some of the data
they need, and help them apply for a grant from the National Institutes of
Health for further studies.
"The infant
neck, particularly before the age of one, is dramatically different from
the neck of, say, you or me," Manley said. "The same is true of
the head, which in infants is soft and compliant - they haven't formed
sutures yet.
"We don't
believe that these crash test dummies are sufficient to represent the
actual biology of the infant head and neck, so we are going to use the
preliminary data to write a grant to develop a much more realistic
model."
In addition,
Goldsmith and graduate student Ken Monson are working with Manley to obtain
fresh cerebral arteries and veins from surgery patients for measurement of
their mechanical properties. Despite the fact that arteries and veins are
embedded in the brain like a net, no one has considered them in models of
how the brain responds to impact.
In the late 1960s,
Goldsmith was chair of a committee at NIH, the Head Injury Model
Construction Committee, that for four years oversaw research to construct a
model of the adult head and brain. Unfortunately, funding dried up in the
1970s, and the research project was dropped.
"Well over
50,000 people die from head injuries each year. Finding out the causes and
procedures is very difficult, but essential," he said.
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