Shaken Baby Syndrome: Simulation via Computational and Physical Modelling

The tenns 'abusive head injury' and 'shaken baby syndrome' refer to a unique pattern of non-accidental traumatic injury occurring in children that many clinicians and researchers have good reason to believe is caused by violent shaking. Typical injuries include subdural haemorrhage, retinal haemorrhage as well as tears to cortical bridging veins. A major paradox is that the injuries induced by a shaking event are much more severe than those caused by even violent single impact head trauma, despite the relatively low accelerations in shaking. Infants younger than 6 months are significantly more vulnerable to the shaken baby syndrome than older infants and children, and one possible explanation is given that the softness of the infant brain and compliant skull structure allows violent motions to be set up. This new mechanisms, as our hypothesis, could have an important role in explaining the basic mechanics of the shaken baby syndrome. Several models of infant head have been created with the optimized anatomical detail and accurate constitutive material properties from literature. The driving input to these models is derived from data generated in our research programme at the Transport Research Laboratory (TRL) with the theory of kinematics rigid body reconstruction. Numerical simulation are applied by using the finite element system LSDYNA, and the consequences of local strain and acceleration in the most susceptible regions have been correlated with clinically observed damage in infant victims, and the brain skull boundary condition is investigated via fluid structure interaction (FSI) method. A shaking testing apparatus has been custom designed with computer aided methodology (CAD), and is manufactured and assembled in situ. The driving of the rig is able to apply stable, repetitive linear motion within the range of accuracy and magnitude of human shaking. A physical head model has been constructed and mounted on the rig with important structures consisting of brain, cerebrospinal fluid (CSF), skull and infantile membrane. The system validates the computational modelling by demonstrating the relative motion of the continuum system within the transparent skull replica. The results are brought together and are able to prove our hypothesis that the compliant head structure can sustain much larger defonnations than the complete one, with the neurological tissue underneath that suffers much defonnation up to failure under the soft spot. The research, as a first exploration in this area, contributes to the study of the infant abusive head injury, and is able to draw the data together in a discussion of the implications for the mechanics of the shaken baby syndrome.EThOS - Electronic Theses Online ServiceGBUnited Kingdo