MODELLING THE SHAKEN BABY SYNDROME

Physical child abuse is common. For the UK alone, an informed estimate is that every year more than 200 infants die from brain injuries inflicted by violent shaking (“Shaken Baby Syndrome”). Around twice this number, who actually survive such treatment, are left with severe mental and physical disability including blindness due to associated damage to the retina (the light-sensitive part of the eye). Although it is now distressingly obvious that shaking often causes debilitating brain and eye injuries, it is unclear how it happens, whilst such combined injuries are rare even in severe accidental head trauma with skull fractures. The work involves the use of LS-DYNA to explore some of the mechanical fundamentals of these phenomena. Specifically, it addresses the difference between motions induced in the brain through the “single event” loading that is normally associated with impacts and those induced by shaking. The paper also describes a set of experiments that measured the accelerations induced by shaking an automotive dummy of a 9-month old child. The “shakers” included young men and women, and middle-aged men and women. They also ranged between small and delicate, and large and muscular. The data from this sort of experiment is essential input to the DYNA simulations.