Prefrontal cortex as a compensatory functional substrate during ataxic overground gait: a correlation study between cortical activity and gait parameters

Purpose: To investigate whether prefrontal cortex (PFC) functioning during ataxic gait is linked to compensatory mechanisms or to the typical intra-subject variability of the ataxic gait. Methods: Nineteen patients with chronic ataxia and fifteen healthy subjects were evaluated. The subjects were requested to walk along a straight distance of 10 meters while PFC oxygenation and gait parameters were assessed. PFC activity was evaluated by NIRO-200 while gait analysis was performed by the SMART-D500. To investigate the intra-subject variability of gait, we calculated the coefficient of multiple correlation (CMC) of the hip, knee and ankle kinematic waveforms furthermore, we evaluated the step width. Results: We observed a positive correlation between PFC bilateral oxygenation changes and the step width (r = 0.54; p = 0.02 for the right PFC, and r = 0.50; p = 0.03 for the left PFC). No correlation was found between PFC activity and CMC of the hip, knee and ankle waveforms. Conclusions: Our results suggest that PFC activity is linked to gait compensatory mechanisms more than to the variability of the joint kinematic parameters caused by a defective cerebellar control.