Experimental Head Injury & Concussion in Monkey Using Pure Linear Acceleration Impact

Abstract

SummaryTranslational acceleration head injury experiment was performed on 12 Japanese monkeys and one baboon using a HYGE sled and a slider-impactor system. All the monkeys became concussed by force ranging 241 to 366G in slider average acceleration and two of them died of concussion (fatal or irreversible concussion). The fatal concussion animals as well as the delayed death ones showed almost unexceptionally rib and clavicle fractures and mediastinal hemorrhage. Subarachnoid hemorrhage seen in six animals were not correlated with the outcome. We were unable to produce visible brain lesions, such as brain contusion, subdural hematoma, or intracerebral hematoma, by using pure trans lational acceleration impacts to the head. It should be misleading to draw a human or primate head injury tolerance limit from the fatal concussion level.Interestingly seven monkeys showed spontaneous eyelid blinking and four showed pupillary light reaction immediately post-impact and at least six animals showed "nor mal" EEG activity ten seconds after the impact. The cause of concussion was discussed and the role of cardiorespiratory supression by the primary shock is suggested.

The Spectrum of Neurobehavioral Sequelae after Repetitive Mild Traumatic Brain Injury: A Novel Mouse Model of Chronic Traumatic Encephalopathy

“…Analyses of data from early nonhuman primate studies of concussion led investigators at the time to believe that approximately half of the potential for concussion during impact to the unprotected movable head was related to head rotation, with the remaining brain injury potential of the blow being related to the contact phenomena of the impact. [86][87][88][89] Although the biodynamics in these primate models were likely more similar to human concussion, such studies were limited to small group size. With regard to modern-day athletes and the biophysics of mTBI, data garnered through helmet accelerometer studies at the youth, high school, and college level have shown that athletes may experience a wide range of head impacts, as well as types of forces, and this research has also suggested that it may be more likely be that the cumulative number of head impacts best correlates with the potential for concussion occurrence or chronic effects.…”

An overview of the basic science of concussion and subconcussion: where we are and where we are going

“…52,70,71,85,89,107 Analyses of the data at that time led investigators to believe that approximately half of the potential for concussion during impact to the unprotected movable head was related to head rotation, with the remaining brain injury potential of the blow being related to the contact phenomena of the impact. 71 Although the biodynamics in these primate models were likely more similar to human concussion, such studies were limited to small group size.…”

Reproducibility and Characterization of Head Kinematics During a Large Animal Acceleration Model of Traumatic Brain Injury

“…Head kinematics have therefore been used to predict TBI pathology in both human and animal models, design safety equipment, and assess the risk of brain injury (2)(3)(4). However, to our knowledge, there have only been a handful of large animal studies that have used sensors (5)(6)(7)(8)(9) and/or high-speed cameras [see Table 1; (8,10,11)] to directly measure the magnitude of head kinematics during acceleration models of injury. To date, no studies have evaluated the reproducibility of head kinematics, which, by definition (65,66), requires the exact same initial injury conditions to be repeated across multiple animals (i.e., methods reproducibility) and/or in separate experiments (i.e., results reproducibility).…”