Shaken-Baby Syndrome Faces New Questions in Court

By EMILY BAZELON
Published: February 2, 2011
New York Times

....Between 1,200 and 1,400 children in the United States sustain head injuries attributed to abuse each year. Most of them are less than a year old. Usually, there’s not much dispute that these children were abused, because doctors discover other signs of mistreatment — cuts, bruises, burns, fractures — or a history of such injuries. There is no exact count of shaken-baby prosecutions, but law-enforcement authorities think that there are about 200 a year. In an estimated 50 percent to 75 percent of them, the only medical evidence of shaken-baby syndrome is the triad of internal symptoms: subdural and retinal hemorrhage and brain swelling.

....Much of the science of shaken-baby syndrome dates from the late 1960s, when a neurosurgeon named Ayub Ommaya conducted a brutal animal experiment to figure out how much acceleration it took to cause a head injury. Ommaya took more than 50 rhesus monkeys and strapped each one into a chair mounted on wheels, leaving their heads unsupported. He placed the chair on a 20-foot-long track, and an air-powered piston sent the monkeys zooming into a wall. Fifteen emerged with some kind of cerebral hemorrhage. Eight of those also had injuries to the brain stem or cervical cord.

Ommaya’s experiment involved neither shaking nor infants. Still, two pediatric specialists, John Caffey and A. Norma Guthkelch, each wrote a paper that pointed to the work as evidence that unexplained subdural bleeding in babies could occur without direct impact to the head and with or without a visible neck injury. In the 1980s, the term “shaken-baby syndrome” came into broad use, and a national prevention and awareness campaign was set in motion.

As the diagnosis of shaken-baby syndrome took hold in medicine, and prosecutors began to bring charges based on it, doctors testified that shaking could generate the same terrible force as throwing a child from a second-story window. It turned out they were wrong. In 1987, a neurosurgeon named Ann-Christine Duhaime published a paper that included the autopsy results of 13 babies with symptoms associated with shaken-baby syndrome. In all of them she found evidence of trauma that was actually caused by impact. She teamed up with biomechanical engineers to create infant-sized dummies equipped with sensors to measure acceleration.“We shook them as hard as we could, and we thought something was wrong, because the accelerations we measured were unexpectedly low,” Duhaime says. Instead, the force level shot up when the testers released the dummies after shaking them, even if they hit a soft surface like a bed or a couch. ***

Later experiments confirmed this finding and have made some doctors and biomechanical engineers skeptical that shaking alone can cause severe brain damage or death. At the same time, the experiments have not ruled this out, Duhaime says. Among other things, the dummies are not live children, and while their heads and necks can exhibit the effects of acceleration, impact on brain tissue is still hard to model. FULL STORY

***This is the paper I have referred to many times-

J Neurosurg. 1987 Mar;66(3):409-15.
The shaken baby syndrome. A clinical, pathological, and biomechanical study
Duhaime AC, Gennarelli TA, Thibault LE, Bruce DA, Margulies SS, Wiser R.