title: Resonance of human brain under head acceleration.
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.
authors.affiliation: Department of Bioengineering, Stanford University, Stanford, CA 94305, USA.
authors.forename: Kaveh
authors.initials: K
authors.lastname: Laksari
authors.affiliation: Department of Bioengineering, Stanford University, Stanford, CA 94305, USA.
authors.forename: Lyndia C
authors.initials: LC
authors.lastname: Wu
authors.affiliation: Department of Bioengineering, Stanford University, Stanford, CA 94305, USA.
authors.forename: Mehmet
authors.initials: M
authors.lastname: Kurt
authors.affiliation: Department of Mechanical Engineering, Stanford University, Stanford, CA 94305, USA.
authors.forename: Calvin
authors.initials: C
authors.lastname: Kuo
authors.affiliation: Department of Bioengineering, Stanford University, Stanford, CA 94305, USA Department of Mechanical Engineering, Stanford University, Stanford, CA 94305, USA dcamarillo@stanford.edu.
authors.forename: David C
authors.initials: DC
authors.lastname: Camarillo
mesh_terms: D000054:Acceleration / Q000009:adverse effects*; D000328:Adult; D001921:Brain / Q000000981:diagnostic imaging / Q000503:physiopathology; D001930:Brain Injuries / Q000000981:diagnostic imaging / Q000503:physiopathology; D006259:Craniocerebral Trauma / Q000000981:diagnostic imaging / Q000503:physiopathology; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D011859:Radiography; D012886:Skull / Q000000981:diagnostic imaging / Q000503:physiopathology
keywords: injury risk criterion; mild traumatic brain injury; repetitive head exposure; resonance frequency; rigid body motion; tagged MRI