![]() Several regions of the brain have been shown to be affected by TBI consistently across DTI analyses. Common metrics derived from the diffusion tensors at each voxel of an image include for example the fractional anisotropy (FA) - a normalized measure of anisotropy -, the apparent diffusion coefficient (ADC) - a rotationally invariant measure of the magnitude of diffusion -, and the mean diffusivity (MD) - the average of the three eigenvalues. As a result, diffusion-based calculations enable quantification of the direction and integrity of axons. However, when hampered by axons and their myelin sheath, diffusion becomes anisotropic. This diffusion is isotropic when it is not obstructed by tissues or barriers. DTI is sensitive to the diffusion of water molecules in the body, and is hindered by extracellular and restricted by intracellular components. DTI can reveal the white matter structures in the brain by quantifying the diffusion of water. In the last decade, diffusion tensor imaging (DTI) has become an important noninvasive tool to investigate white matter changes in TBI. Additionally, the correlation between head trauma and cognitive decline has been shown in several studies in adult as well as adolescent populations. ![]() Within the literature about traumatic brain injury in athletes, there exist several studies showing anatomical and cognitive differences before and after a concussion in sports such as hockey and football. As the disease progresses, further deterioration can occur, accompanied by lack of insight, poor judgment and even overt dementia. CTE, which has been most frequently associated with boxing, causes deteriorations in attention, concentration, and memory, as well as disorientation and confusion, and is occasionally accompanied by dizziness and headaches. A recent study on post-mortem brains, which included several American football players, showed that repeated mild TBI may progress to chronic traumatic encephalopathy (CTE). Another possible consequence of TBI consists of local shearing of axons at the gray/white matter interface.īoth of these shearing processes disrupt axonal connections that are important to brain function. ĭiffuse axonal injury (DAI), also known as traumatic axonal injury (TAI), is one of the consequences of traumatic brain injury, and is thought to be caused by shearing of nerve fibers due to the sudden acceleration and deceleration, sometimes combined with rotational and vibration forces. Mechanical trauma to the brain triggers a complex cascade of structural, physiological, neuro-chemical and neuro-metabolic events due to the acceleration and deceleration forces, and this can cause further disruption of the neuronal cell membrane and axonal stretching. ![]() ![]() Ĭoncussions are associated with a host of symptoms including behavior changes, impairments of memory and attention, headache, unsteadiness, etc., leading to more permanent cognitive impairment. Mild traumatic brain injury (mTBI), also known as concussive injury affects 1.7 million Americans annually, of which 300,000 are due to sports and recreational activities. Brain trauma in contact sports, such as football, rugby, and boxing, has been the focus of recent media attention due to high profile cases involving professional athletes. ![]()
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