Quantifying Brain Connectivity During Restricted Knee Movement

Knee pain and injury are commonly encountered in clinical practice with many causes, including mechanical, hormonal, environmental, and anatomical factors. Changes in the central nervous system (CNS) associated with sensory, motor, and emotional processing are also typically involved. On the other hand, gait anomalies subsequent to knee injury, recovery, and recurring impairment, as well as the influence on CNS activity, remain to be elucidated. Cortical activity obtained via electroencephalogram (EEG) signals can be used to investigate the underlying involvement of the CNS associated with knee pathology and gait dysfunction. In this study, cortical connectivity on healthy individuals was captured and analyzed based on partial directed coherence. The subjects wore a knee brace at varying degrees during the range of motion to restrict knee mobility, hence emulating knee pathology. The results demonstrated that restricted knee movement reduced the information flow from the left to the right ventrolateral prefrontal cortex (Fp1 to Fp2), while increasing connectivity from the sensorimotor cortex (Cz) to the right prefrontal cortex (Fp2). These findings suggest that changes in the EEG patterns are possibly correlated with changes in gait and posture in patients with knee motion restrictions. The increased activity of the left prefrontal cortex was associated with increased attention to the sensory input due to knee restriction which indicates top-down control of sensory input. In addition, the right prefrontal cortex (Fp2) played a role in sensorimotor learning and adaptation as was required in the current protocol when walking with knee restriction.