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Correlation Between Brain Injury and Intracranial Pressures in Experimental Head Impacts
Published September 05, 1979 by International Research Council on Biokinetics of Impact in Switzerland
In all head impacts (helmeted or unhelmeted head) a pressure gradient develops in the brain due to head motion; high positive pressures develop near the impact site and negative (less than atmospheric) pressures develop opposite the impact. The finite element model can accurately predict these pressures provided the Poisson's ratio is varied to accommodate pressure release in the longer duration head accelerations. Intracranial pressures in the helmeted head have a characteristic shape. They are, in general, lower and of longer duration. High frequency components have been eliminated by crushing of the helmet liner. The sharp spike-shaped head accelerations and pressures which characterize a hard surface head impact do not develop. Brain response in the helmeted head is more like the response which occurs when head impacts a well-padded surface.
The same general pressure-injury relationship seems to apply to the helmeted and unhelmeted head impacts; however, additional simulations are required to substantiate this observation. Pressures above 34 psi are associated with injury. The results show that padding in the helmet liner, or on the impact surface, can be very effective in reducing intracranial pressures and minimizing brain injury