Physical properties of the human head: Mass, center of gravity and moment of inertia

Yoganandan, Narayan; Pintar, Frank A.; Zhang, Jiangyue; Baisden, Jamie

doi:10.1016/j.jbiomech.2009.03.029

Cited by 175 publications

(113 citation statements)

References 34 publications

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“…The full inventory of gesture types is presented in Table 3. We illustrate prototypical movements along particular axes in Figure 3, using mathematical conventions for 3D spatial coordinates and following bio-mechanical and physiological studies on head movements (Yoganandan et al 2009).…”

Section: Head Gesture Annotationmentioning

confidence: 99%

The ALICO corpus: analysing the active listener

Malisz

Włodarczak

Buschmeier

et al. 2016

Lang Resources & Evaluation

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The ALICO corpus: analysing the active listener. Abstract The Active Listening Corpus (ALICO) is a multimodal data set of spontaneous dyadic conversations in German with diverse speech and gestural annotations of both dialogue partners. The annotations consist of short feedback expression transcriptions with corresponding communicative function interpretations as well as segmentations of interpausal units, words, rhythmic prominence intervals and vowel-to-vowel intervals. Additionally, ALICO contains head gesture annotations of both interlocutors. The corpus contributes to research on spontaneous human-human interaction, on functional relations between modalities, and timing variability in dialogue. It also provides data that differentiates between distracted and attentive listeners. We describe the main characteristics of the corpus and briefly present the most important results obtained from analyses in recent years.

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Section: Head Gesture Annotationmentioning

confidence: 99%

The ALICO corpus: analysing the active listener

Malisz

Włodarczak

Buschmeier

et al. 2016

Lang Resources & Evaluation

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“…We used the largest directional component of rotational acceleration as base excitation. We used previously published values for the moment of inertia [51], and based on the results shown in Fig. 2(a), we assumed a 28 Hz natural frequency.…”

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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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“…28,29 The injury mechanism of TBI caused by MVC is characterized by very forceful acceleration-deceleration of the head and/or the head striking an object. 30,31 We compared cortical thicknesses in survivors who experienced mTBI symptoms in the peritrauma period after MVC and MVC survivors who did not experience mTBI symptoms.…”

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confidence: 99%

Early Cortical Thickness Change after Mild Traumatic Brain Injury following Motor Vehicle Collision

Wang

Xie

Cotton

et al. 2015

Journal of Neurotrauma

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In a motor vehicle collision (MVC), survivors often receive mild traumatic brain injuries (mTBI). Although there have been some reports of early white matter changes after an mTBI, much less is known about early cortical structural changes. To investigate early cortical changes within a few days after an MVC, we compared cortical thickness of mTBI survivors with nonmTBI survivors, then reexamined cortical thickness in the same survivors 3 months later. MVC survivors were categorized as mTBI or non-mTBI based on concussive symptoms documented in emergency departments (EDs). Cortical thickness was measured from MRI images using FreeSurfer within a few days and again at 3 months after MVC. Post-traumatic stress symptoms and physical conditions were also assessed. Compared with the non-mTBI group (n = 23), the mTBI group (n = 21) had thicker cortex in the left rostral middle frontal (rMFG) and right precuneus gyri, but thinner cortex in the left posterior middle temporal gyrus at 7.2 -3.1 days after MVC. After 3 months, cortical thickness had decreased in left rMFG in the mTBI group but not in the non-mTBI group. The cortical thickness of the right precuneus region in the initial scans was positively correlated with acute traumatic stress symptoms for all survivors and with the number of reduced activity days for mTBI survivors who completed the follow-up. The preliminary results suggest that alterations in cortical thickness may occur at an early stage of mTBI and that frontal cortex structure may change dynamically over the initial 3 months after mTBI.

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Physical properties of the human head: Mass, center of gravity and moment of inertia

Cited by 175 publications

References 34 publications

The ALICO corpus: analysing the active listener

The ALICO corpus: analysing the active listener

Mechanistic Insights into Human Brain Impact Dynamics through Modal Analysis

Early Cortical Thickness Change after Mild Traumatic Brain Injury following Motor Vehicle Collision

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