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Linear wave propagation in traumatic brain injury

Linear wave propagation in traumatic brain injury
Linear wave propagation in traumatic brain injury

The research presented in this thesis has focussed on two forms of traumatic brain injury (TBI) that are both major causes of mortality: Diffuse axonal injury (DAI0 and acute subdural haematoma (ASDH).

In a new approach to the formulation of injury criteria, the use of frequency response functions (BRF) to calculate the strain in the corpus callosum from rigid-body skull motions has been justified with a validated, 2D finite element (FE) model. The strain response in the corpus callosum remains linear to within 13% for coronal-plane rotational acceleration up to 12 krad.s-2, well beyond the threshold for DAI in this plane. Peak strains in the corpus callosum, calculated with BRF, vary by a factor of 1.5 for a sequence of half-sine waveforms of equal head injury criterion (HIC), for pulse durations between 8 ms and 25 ms. Thus, the HIC and BRF approaches can give different predictions of injury outcome. The major advantage of the BRF approach is the speed of injury prediction, which is of the order of 104 times faster than direct FE analysis for the example given.

Two analytical models have been used to investigate TBI from sharp blows to the head where skull deformations and local contact phenomena prevail. A half-space model has shown that the shear properties of the brain may be varied over a considerable range with respect to typical human values with no effect on pressure response. The same conclusion is obtained from a 2D coronal plane FE model, and from a two-layer analytical model that incorporates a representation of the cerebrospinal fluid and trabeculae. The two-layer model has demonstrated that even the smallest amount of elasticity in the subarachnoid space (6 Pa) causes significant coupling between the skull and brain.

University of Southampton
Bradshaw, Douglas Robert Saunders
c5dfcf72-7745-4359-a38e-3446b96bd696
Bradshaw, Douglas Robert Saunders
c5dfcf72-7745-4359-a38e-3446b96bd696

Bradshaw, Douglas Robert Saunders (2001) Linear wave propagation in traumatic brain injury. University of Southampton, Doctoral Thesis.

Record type: Thesis (Doctoral)

Abstract

The research presented in this thesis has focussed on two forms of traumatic brain injury (TBI) that are both major causes of mortality: Diffuse axonal injury (DAI0 and acute subdural haematoma (ASDH).

In a new approach to the formulation of injury criteria, the use of frequency response functions (BRF) to calculate the strain in the corpus callosum from rigid-body skull motions has been justified with a validated, 2D finite element (FE) model. The strain response in the corpus callosum remains linear to within 13% for coronal-plane rotational acceleration up to 12 krad.s-2, well beyond the threshold for DAI in this plane. Peak strains in the corpus callosum, calculated with BRF, vary by a factor of 1.5 for a sequence of half-sine waveforms of equal head injury criterion (HIC), for pulse durations between 8 ms and 25 ms. Thus, the HIC and BRF approaches can give different predictions of injury outcome. The major advantage of the BRF approach is the speed of injury prediction, which is of the order of 104 times faster than direct FE analysis for the example given.

Two analytical models have been used to investigate TBI from sharp blows to the head where skull deformations and local contact phenomena prevail. A half-space model has shown that the shear properties of the brain may be varied over a considerable range with respect to typical human values with no effect on pressure response. The same conclusion is obtained from a 2D coronal plane FE model, and from a two-layer analytical model that incorporates a representation of the cerebrospinal fluid and trabeculae. The two-layer model has demonstrated that even the smallest amount of elasticity in the subarachnoid space (6 Pa) causes significant coupling between the skull and brain.

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Published date: 2001

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Local EPrints ID: 464328
URI: http://eprints.soton.ac.uk/id/eprint/464328
PURE UUID: ae1d1ab7-c062-4278-9589-397a7d091ffa

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Date deposited: 04 Jul 2022 22:17
Last modified: 23 Jul 2022 02:06

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Author: Douglas Robert Saunders Bradshaw

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