Evaluation of gait impairment in mice subjected to craniotomy and traumatic brain injury.

Traumatic brain injury (TBI) represents a significant global health burden and causes long-lasting neuromotor deficits, particularly in individuals who sustain severe TBI. A better understanding of gait impairment after experimental TBI will provide valuable information for the recovery and rehabilitation of TBI survivors. Here we utilised the DigiGait system to perform kinematic gait analysis in mice subjected to brain injury induced by the controlled cortical impact (CCI) TBI model. Naïve mice, non-craniotomised and craniotomised mice were included as controls. The temporal and spatial profile of gait was mapped from 3h to 1-week post-TBI. Remarkably, there was a noticeable alteration in some aspects of gait in craniotomised sham mice from their pre-surgery baseline at various time-points over the testing period. This was not observed in naïve mice or non-craniotomised sham controls over the same time period. This finding indicates that the craniotomy procedure alone effects gait. When craniotomised mice were subjected to TBI, additional deleterious effects on gait function were observed, including forelimb stance and swing duration as well as left hindlimb swing and stride duration and frequency. Hence, mice subjected to CCI-induced TBI develop clear alterations in gait but part of this is attributable to the effect of craniotomy alone. This study also highlights the need to include both non-craniotomised and craniotomised sham mice as controls when undertaking the CCI-induced model of TBI, particularly when early time points are being evaluated.