Relative brain displacement and deformation during constrained mild frontal head impact

Feng, Yuan; Abney, Teresa M.; Okamoto, Ruth J.; Pless, Robert; Genin, Guy M.; Bayly, Philip V.

doi:10.1098/rsif.2010.0210

Cited by 105 publications

(118 citation statements)

References 23 publications

(51 reference statements)

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“…We used tagged MRI measurements from a previously published study of brain displacements (three human male subjects aged 23-44) in 2 cm frontal head drops in the sagittal plane [24]. These impacts resulted in maximum linear and rotational accelerations of 1.5 g and 140 rad s To investigate the motion of the brain relative to the skull, we first determined all the brain pixels that were available throughout the tagged MRI measurement for each subject (approx.…”

Section: Unconstrained Kinematicsmentioning

confidence: 99%

“…PCA of the MRI measurements was achieved by combining the brain's translation in the PA direction ( Figure 2. Principal component analysis of rigid-body motion based on tagged MRI data [24]: (a) 3DOF motion of brain in the sagittal plane is shown for the three subjects. There is a strong correlation between the 3DOF such that it can be approximated by a single DOF, (b) first few principal components for the rigid-body motion are shown as the ratio of total variance.…”

Section: Constrained Kinematicsmentioning

confidence: 99%

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Resonance of human brain under head acceleration

Laksari

Kurt

et al. 2015

J. R. Soc. Interface.

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Although safety standards have reduced fatal head trauma due to single severe head impacts, mild trauma from repeated head exposures may carry risks of long-term chronic changes in the brain's function and structure. To study the physical sensitivities of the brain to mild head impacts, we developed the first dynamic model of the skull-brain based on in vivo MRI data. We showed that the motion of the brain can be described by a rigid-body with constrained kinematics. We further demonstrated that skull-brain dynamics can be approximated by an under-damped system with a low-frequency resonance at around 15 Hz. Furthermore, from our previous field measurements, we found that head motions in a variety of activities, including contact sports, show a primary frequency of less than 20 Hz. This implies that typical head exposures may drive the brain dangerously close to its mechanical resonance and lead to amplified brain-skull relative motions. Our results suggest a possible cause for mild brain trauma, which could occur due to repetitive low-acceleration head oscillations in a variety of recreational and occupational activities.

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Section: Unconstrained Kinematicsmentioning

confidence: 99%

Section: Constrained Kinematicsmentioning

confidence: 99%

Resonance of human brain under head acceleration

Laksari

Kurt

et al. 2015

J. R. Soc. Interface.

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“…There are several limitations associated with the work presented here. The FE model used in this study had previously been partially validated with sparse cadaver experiments and not thoroughly validated against in vivo MRI data [25,68]. We believe that more accurate and region specific material properties and more detailed geometries, particularly the cortical gyri, will render the dynamic differences more pronounced.…”

mentioning

confidence: 99%

Mechanistic Insights into Human Brain Impact Dynamics through Modal Analysis

et al. 2018

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Although concussion is one of the greatest health challenges today, our physical understanding of the cause of injury is limited. In this Letter, we simulated football head impacts in a finite element model and extracted the most dominant modal behavior of the brain's deformation. We showed that the brain's deformation is most sensitive in low frequency regimes close to 30 Hz, and discovered that for most subconcussive head impacts, the dynamics of brain deformation is dominated by a single global mode. In this Letter, we show the existence of localized modes and multimodal behavior in the brain as a hyperviscoelastic medium. This dynamical phenomenon leads to strain concentration patterns, particularly in deep brain regions, which is consistent with reported concussion pathology. DOI: 10.1103/PhysRevLett.120.138101 Traumatic brain injury (TBI) is a major cause of death and disability in the United States, contributing to about 30% of all injury-related deaths [1,2]. Every year, millions of Americans are diagnosed with TBI [3,4], 80% of which are categorized as mild [2]. Undiagnosed cases, due to either lack of clinical expertise or underreporting, might be twice as high [5][6][7][8]. Given that mild TBI (MTBI), or concussion, has become a serious health concern in society, the burden of understanding and preventing it has become ever more indisputable for clinicians and physicists alike.Efforts to model the brain's physics date back to the 1940s when Holbourn proposed the head as a mechanical system and explored the relation between the input to this system (in the form of head motion) to the output (in the form of relative brain displacement) [9,10]. Kornhauser proposed isodisplacement curves in a second-order springmass system representing relative brain displacement as a measure for classifying injury [11]. Others have also showed that, in different loading regimes, injury could be more sensitive to peak acceleration or maximum change in velocity or a combination of both [12,13]. Since then, many scientists have investigated the brain's response in severe scenarios of TBI with skull flexure [14,15], and more recently in mild scenarios with mostly inertial loading on the brain [16][17][18]. In particular, for helmeted sports, much of previous research has focused on brain deformation while assuming a rigid skull. In time, with the advances in imaging techniques, axonal injury, which requires excessive regional stretching of axons [19,20], has become one of the leading hypotheses behind the mechanism of concussions. Confirming this hypothesis, strain in the brain and specifically strain in the periventricular region of the brain-with the highest density of axon fibers-have been shown to correlate best with acute concussion and longterm neurological deficits [21][22][23][24]. However, dynamical behavior of the brain during rapid head motions with various amplitudes, durations, and directions, as well as the reason for higher susceptibility of these deep regions of the brain to strain are still largely unknow...

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“…Parameters such as the elastic modulus, Poisson's ratio and stiffness matrix components can then be determined. The resistive strain gauge is perhaps the most ubiquitous strain sensor in a mechanical engineering laboratory and provides the average strain in a specified direction under the area of the gauge, of the order of 1-10 mm 2 . However, multiple measurements require multiple sensors, which have to be glued to the sample as they rely on physical contact to transfer surface strain to the gauge.…”

Section: Introductionmentioning

confidence: 99%

“…Depth resolved techniques go a step further and provide information of the material under the surface. Whereas neutron diffraction can provide strain fields through the thickness of crys talline materials such as metals, magnetic resonance imaging can be adapted to measure mechanical deformation of spin rich materials such as tissues containing water and fat [2]. X-ray computed tomography relies on attenuation to reconstruct the material structure and is combined with digital volume correlation (DVC) to evaluate 3-D displacement and strain fields [3].…”

Section: Introductionmentioning

confidence: 99%

Tomographic sensing of displacement fields

Ruiz

2013

Advanced Photonics 2013

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A wavelength scanning interferometry system is used to measure all the orthogonal components of the displacement field inside semitransparent scattering materials. A near infrared tunable laser illuminates a sample from multiple directions. The image of the sample is recombined with a reference beam on a photodetector array. As the laser freque ncy is linearly tuned during a scan, a sequence of speckle interferograms is recorded. In order to reconstruct the sample structure, Fourier transformation is performed on a pixel by pixel basis along the temporal axis of the 3-D data cube obtained. Multiple displacement sensitivities are achieved by introducing different optical delays between the reference and the illumination beams, which separate the reconstruction signals in the frequency domain. Phase changes due to mechanical loading of the sample can finally be measured and combined to obtain all orthogonal components of the displacement field in a convenient coordinate system. Controlled rigid body rotations of an epoxy phantom have been used to validate the methodology.

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Relative brain displacement and deformation during constrained mild frontal head impact

Cited by 105 publications

References 23 publications

Resonance of human brain under head acceleration

Resonance of human brain under head acceleration

Mechanistic Insights into Human Brain Impact Dynamics through Modal Analysis

Tomographic sensing of displacement fields

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