Auckland Bioengineering Institute

Tom Lintern

Tom Lintern began with a Bachelor of Engineering (Honours) specialising in Biomedical Engineering, went on to complete a doctorate specialising in Bioengineering, and is now with Deloitte as a Management Consultant.

Alumnus profile

Professor Martyn Nash with Thomas Lintern in full regalia on the day of Thomas' PhD graduation ceremony

I made the shift north to Auckland from Christchurch to pursue Engineering in 2006. An interest in maths and the medical sciences led me to Engineering Science and a specialty in Biomedical Engineering. After completing my BE(Hons), I was left with a decision to make – apply for a job  or jump into post-graduate studies.

As it happens, I was offered a PhD Scholarship and a project to investigate the injuries that occur during Abusive Head Trauma (or Shaken Baby Syndrome). My desire to get stuck into research, and the opportunity to investigate an issue that was top of mind in NZ at the time, led me to accepting the scholarship and committing to a PhD for the next 4 years.

Enrolling in a PhD at the Auckland Bioengineering Institute was a great decision. My PhD gave me a chance to mature and develop a work ethic and core skills that I have been able to apply to my career. Studying a PhD also provided me the opportunity to work with great people, travel the world, and instilled an appreciation for good coffee.

Since graduating I have been working as a Management Consultant at Deloitte. It was a tough decision to make, but what attracted me to consulting was chance to apply my engineering skills to commercial problems and to learn more about business. Although working in business is very different to bioengineering research, the analytical approach to solving problems, and the strong communication skills developed during my PhD has provided me with tools to succeed.

About Tom's doctorate

Modelling Infant Head Kinematics in Abusive Head Trauma

Abusive head trauma (AHT) is a potentially fatal result of child abuse, but the mechanisms by which injury occur are often unclear. In this thesis, a novel computational framework for investigating head kinematics during AHT was developed using OpenSim (Delp et al., 2007), and was validated with kinematic measurements during shaking of an experimental phantom. The framework was used to investigate the biomechanics of AHT using model-based interpretation of animal shaking experiments, and computational studies simulating the shaking of human infants.

The lamb was used as an in vivo experimental analogue of AHT. An OpenSim computational model of the lamb was developed and used to interpret biomechanical data from shaking experiments. Sagittal plane acceleration components of the animal’s head during shaking were used to provide in vivo validation of the computational framework. Results demonstrated that peak accelerations occurred when the head impacted the torso and produced acceleration magnitudes exceeding 200 m∙s-2. The computational model demonstrated good agreement with the experimental measurements and was able to reproduce the extreme accelerations that occur during impact. The biomechanical results demonstrate the utility of using a coupled rigid-body modelling framework to describe infant head kinematics in AHT.

To investigate AHT in human infants, a novel probabilistic analysis of head kinematics during shaking was performed. A deterministic OpenSim model, incorporating an infant’s mechanical properties, was subjected to a variety of shaking motions. Monte Carlo analyses were used to simulate the range of infant kinematics produced as a result of varying both the mechanical properties and the type of shaking motions. By excluding physically unrealistic shaking motions, worst-case shaking scenarios were simulated and compared to existing injury criteria for a newborn, 4.5 months, and a 12 months infant. None of these cases produced head kinematics that exceeded previously estimated subdural haemorrhage injury thresholds. The results of this study provide no biomechanical evidence to demonstrate how shaking alone can cause the injuries observed in AHT, suggesting either that additional factors, such as impact, are required, or that the current estimates of injury thresholds should be interpreted with caution.

Tom's doctoral research project was supervised by: