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J R Soc Interface. 2015 Jul 6;12(108):20150331. doi: 10.1098/rsif.2015.0331.

Resonance of human brain under head acceleration.

Author information

1
Department of Bioengineering, Stanford University, Stanford, CA 94305, USA.
2
Department of Mechanical Engineering, Stanford University, Stanford, CA 94305, USA.
3
Department of Bioengineering, Stanford University, Stanford, CA 94305, USA Department of Mechanical Engineering, Stanford University, Stanford, CA 94305, USA dcamarillo@stanford.edu.

Abstract

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.

KEYWORDS:

injury risk criterion; mild traumatic brain injury; repetitive head exposure; resonance frequency; rigid body motion; tagged MRI

PMID:
26063824
PMCID:
PMC4528602
DOI:
10.1098/rsif.2015.0331
[Indexed for MEDLINE]
Free PMC Article

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