Traumatic Brian Injury Can Occur From Head-Injury Even Without Concussion

Concussion-like deficits after impact injury, lower shear diffuse stress after blast exposure in mice

HealthDay News — Closed-head impact injuries can induce pathologic traumatic brain injury, independent of concussive signs, according to a study published online January 18 in Brain.

Chad A. Tagge, from the Boston University School of Medicine, and colleagues examined post-mortem brains from teenage athletes in the subacute period after mild closed-head impact injury. A mouse model of lateral closed-head impact injury that uses momentum transfer to induce traumatic head acceleration was developed to examine causal mechanisms. 

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The researchers note that astrocytosis, myelinated axonopathy, microvascular injury, perivascular neuroinflammation, and phosphorylated tau protein pathology were found in the post-mortem brains. Abrupt onset, transient course, and rapid resolution of a concussion-like syndrome characterized by altered arousal, contralateral hemiparesis, truncal ataxia, locomotor and balance impairments, and neurobehavioral deficits was exhibited in unanesthesetized mice subjected to unilateral impact. There was a correlation for experimental impact injury with axonopathy, blood-brain barrier disruption, astrocytosis, microgliosis, monocyte infiltration, and phosphorylated tauopathy in cerebral cortex ipsilateral and subjacent to impact. Concussion-like deficits occurred after impact injury but not after blast exposure under experimental conditions. Compared with blast exposure, impact injury generated focal point loading on the head and seven-fold greater peak shear stress in the brain.

“These results indicate that closed-head impact injuries, independent of concussive signs, can induce traumatic brain injury as well as early pathologies and functional sequelae associated with chronic traumatic encephalopathy,” the authors write.

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