Neurological functional evaluation based on accurate motions in big animals with traumatic brain injury

Abstract

An accurate and effective neurological evaluation is indispensable in the treatment and rehabilitation of traumatic brain injury. However, most of the existing evaluation methods in basic research and clinical practice are not objective or intuitive for assessing the neurological function of big animals, and are also difficult to use to qualify the extent of damage and recovery. In the present study, we established a big animal model of traumatic brain injury by impacting the cortical motor region of beagles. At 2 weeks after successful modeling, we detected neurological deficiencies in the animal model using a series of techniques, including three-dimensional motion capture, electromyogram and ground reaction force. These novel technologies may play an increasingly important role in the field of traumatic brain injury diagnosis and rehabilitation in the future. The experimental protocol was approved by the Animal Care and Use Committee of Logistics University of People's Armed Police Force (approval No. 2017-0006.2).

Keywords: electromyogram; evaluation method; ground reaction force; motion capture; nerve regeneration; neural regeneration; neurological deficiency; traumatic brain injury.

Figure 1

Construction of the motion capture platform. (A) High speed cameras were placed around the treadmill and the visual field was adjusted before motion capture. (B) Four markers were attached to each side of the hindlimbs and an endpoint (▴) was set simultaneously. L: Left hindlimb; R: right hindlimb; a–d: major joints. (C) Localization of the markers in the motion capture system. 1–6: High speed cameras 1–6.

Figure 2

Surface electromyogram (sEMG) and vertical ground reaction force (vGRF) changes in the traumatic brain injury (TBI) beagle model. Damage was localized in the right cerebral cortex. (A) Schematic diagram of sEMG and vGRF detection. (B) Voltages of sEMG on bilateral hindlimbs in the control group were similar under the sampling frequency of 1500 Hz. (C) sEMG changes were regular and symmetric between the left and right hindlimb in the control group. (D) Voltage of sEMG on the right hindlimb was significantly higher than that of the left hindlimb. (E) The curve of sEMG change on the left hindlimb was almost a straight line that was asymmetrical with the right hindlimb in the model group. (F) Average sEMG voltage of the right hindlimb was significantly higher than that of the left hindlimb. (G) The curve of vGRF change was irregular in the model group and regular in the control group. (H) Average force of the right hindlimb was significantly higher than that of the left hindlimb. RHL: Right hindlimb; LHL: left hindlimb; L: left; R: right. Data in Figure 2F and H are expressed as the mean ± SD, and analyzed by independent-sample t test. **P < 0.01.

Figure 3

Gait analysis outcomes of the hindlimbs in the traumatic brain injury (TBI) beagle model. (A) Trajectory of each joihindlimbsnt was regular in the control group. (B) Motion trajectories of the left and right hindlimbs were regular and symmetric in the control group. (C, D) Regular changes were found in the joint trajectory, step length and joint angles (b and c) in the control group. (E) Trajectory of each single joint was irregular in the model group. (F) Motion trajectory of the left hindlimb was irregular and asymmetrical with that of the right hindlimb in the model group. (G, H) Changes of joint trajectory in the red dotted line frame, step length and joint angles were irregular for left hindlimb and regular for the right hindlimb in the model group. (I) Height changes were regular for bilateral hindlimbs in the control group, indicated by the area diagram. (J) Height change of the left hindlimb was significantly lower than that of the right hindlimb in the model group. (K) Average height of the right hindlimb was significantly higher than that of the left hindlimb. Joint trajectory is marked by red arrows in E and F. RHL: Right hindlimb; LHL: left hindlimb; L: left; R: right. Data are expressed as the mean ± SD, and analyzed by independent-sample t-test. *P < 0.05.