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Therapeutic Strategies and Future Research
Published in Mark A. Mentzer, Mild Traumatic Brain Injury, 2020
Rehabilitation focuses currently on the alleviation of physical, cognitive, communicative, neurobehavioral, and psychological deficits arising from brain injury. Acquired brain injury is now viewed as a collection of various diseases that may contribute or accelerate a range of neurodegenerative conditions (Ashley and Hovda, 2018). A primary component of brain dysfunction is diffuse axonal injury (DAI), identified as the primary component in 40–50% of all traumatic brain injuries (Meythaler et al., 2001). DAI is specific to brain regions including the parasagittal white matter in the cerebral cortex, the corpus callosum, and the pontine-mesencephalic junction adjacent to the superior cerebellar peduncles (Graham et al., 1987).
Mechanical Investigations of Biological Tissues Using Tensile Loading and Indentation
Published in Adil Al-Mayah, Biomechanics of Soft Tissues, 2018
The brain is subjected to many impact scenarios, such as sport and automobile accidents (O’Riordain et al. 2003, Rueda and Gilchrist 2009), resulting in traumatic injuries ranging from minor damage, such as concussion, to serious injuries, such as diffuse axonal injury (DAI). In the latter scenario, some cases can affect the function control of biological organs as the axon of the nerve cell is severely damaged. To study the response of the brain during these traumatic events, numerous research studies have developed numerical models to investigate brain dynamics during various loading conditions (Kleiven and Hardy 2002, Raul et al. 2006, Kleiven 2007, Ho and Kleiven 2009, Rueda and Gilchrist 2009, Zhang et al. 2011). These models are dependent on the mechanical properties of the biological tissues to present a relatively biofidelic prediction. In the field of neuroscience, the brain structure is divided into white and gray matters. The white matter consists of axons (myelinated nerve cells), and the gray matter consists of somas (cell bodies). The axons extend through the white matter to form its fibrous structure. Several studies have investigated the mechanical properties of brain tissues, as unimatter, using the tensile testing technique (Miller and Chinzei 2002, Velardi et al. 2006, Tamura et al. 2008). Rashid et al. (2014) evaluated the stiffness of brain tissues under stretching, as shown in Figure 2.18. Specifically, they evaluated the elastic moduli E1, E2, and E3 at strain ranges of 0%–10%, 10%–20%, and 20%–30%, respectively, for porcine brain samples with different diameters (Rashid et al. 2014). Their results are summarized in Table 2.1.
Cumulative effects of subsequent concussions on the neural patterns of young rugby athletes: data from event-related potentials
Published in Research in Sports Medicine, 2023
Karim Bennys, Germain U. Busto, Jacques Touchon
Diffuse axonal injury, due to the head trauma or rotational acceleration, appears to be a central pathogenic mechanism of concussion (Zetterberg et al., 2019). Consequences seem, however, primarily functional without any apparent structural damage detectable using neuroimaging techniques. Clinical symptoms, including headache, fatigue, attention deficit, memory impairment or anxiety, can develop hours after injury and are usually transient (1–12 weeks). Nevertheless, 10–15% of concussed players still report symptoms and cognitive deficits months or even years after the event (Rice et al., 2018; Zetterberg et al., 2019). Due to their still-developing brains, young players appear particularly vulnerable to repeated trauma or long-term repercussions (Narayana et al., 2019). Moreover, accumulating evidence suggests that repeated head injuries should be of even greater concern because they are associated with an increased risk of developing dementia with features of both chronic traumatic encephalopathy (CET) and Alzheimer’s disease (AD) (Agrawal et al., 2022; Hay et al., 2016; Lee et al., 2019; Mez et al., 2017; Shively et al., 2012). A study of retired athletes found that those reporting three or more concussions during their career had a three-fold increase in self-reported memory complaints and a five-fold increase in mild cognitive impairment (MCI) diagnosis relative to non-concussed athletes (Guskiewicz et al., 2005).
Head injury criteria assessment using head kinematics from crash tests and accident reconstructions
Published in Traffic Injury Prevention, 2023
Jonas Östh, Katarina Bohman, Lotta Jakobsson
Traumatic brain injury remains as one of the most frequent injuries for vehicle occupants. A review of NASS-CDS head AIS2+ injuries for 1993–2015 showed that while the risk of skull fracture in frontal impacts was constant over the period, the risk of brain MAIS2+ injury increased (Craig et al. 2020). For this reason, the Brain Injury Criterion (BrIC, Takhounts et al. 2013), was suggested to be introduced for use with the THOR-50M Anthropometric Test Device (ATD, Craig et al. 2020). BrIC is a function of the head peak rotational velocities. Hence, it accounts for head rotational motion which is an important predictor for brain injury. Rotational induced brain injuries can be diffuse brain injuries ranging from mild concussion to cerebral concussion and diffuse axonal injury including disruption of axons (Schmitt et al. 2019).
Effect of axonal fiber architecture on mechanical heterogeneity of the white matter—a statistical micromechanical model
Published in Computer Methods in Biomechanics and Biomedical Engineering, 2022
Hesam Hoursan, Farzam Farahmand, Mohammad Taghi Ahmadian
Human brain white matter consists of axonal bundles which connect nerve cell bodies mostly located in the grey matter. A sudden inertial loading on the head can cause Diffuse Axonal Injury (DAI) of white matter, which involves axonal damage in a variety of modes. Among the failure modes of axons, rapid stretching of neural tracts, leading to the impairment of axoplasmic transport and subsequent swelling and neuropathologic problems, has been reported to be the prevailing failure mode (McKenzie et al. 1996; Smith and Meaney 2000; Di Pietro 2013). DAI tends to occur in three anatomical regions of white matter, known as the “injury triad”: the lobar white matter (including corona radiata), the corpus callosum, and the dorsolateral quadrant of the rostal brainstem, adjacent to the superior cerebellar peduncle (Tsao 2012).