Gait analysis in a rat model of traumatic brain injury

Gait disruptions following traumatic brain injury (TBI) are noted in the clinical population. To date, thorough analysis of gait changes in animal models of TBI to allow for correlation of pathological alterations and utilization of this as a therapeutic outcome have been limited. We therefore assessed gait using the DigiGait analysis system as well as overall locomotion using the Beam Walk test in adult male Sprague-Dawley rats following a commonly used model of TBI, parietal lobe controlled cortical impact (CCI). Rats underwent DigiGait baseline analysis 24 h prior to injury, followed by a moderate CCI in the left parietal lobe. Performance on the DigiGait was then assessed at 1, 3, 7, and 14 days post-injury, followed by histological analysis of brain tissue. Beam walk analysis showed a transient but significant impairment acutely after injury. Despite observance of gait disturbance in the clinical population, TBI in the parietal lobe of rats resulted in limited alterations in hind or forelimb function. General hindlimb locomotion showed significant but transient impairment. Significant changes in gait were observed to last through the sub-acute period, including right hindpaw angle of rotation and left forelimb and right hindlimb swing phase duration. Slight changes that did not reach statistical significant but may reflect subtle impacts of TBI on gait were reflected in several other measures, such as stride duration, stance duration and stance width. These results demonstrate that moderate-severe injury to the parietal cortex and underlying structures including corpus callosum, hippocampus, thalamus and basal ganglia result in slight changes to gait that can be detected using the Digigait analysis system.