EEG AND EMG SENSORIMOTOR MEASUREMENTS TO ASSESS PROPRIOCEPTION FOLLOWING ACL RECONSTRUCTION

The Anterior Cruciate Ligament (ACL) is the primary source of rotational stability in the knee. When the ACL is torn, it typically must be repaired through reconstructive surgery, however, surgery may result in proprioceptive deficiencies in the knee. Proprioception plays an important role in spatial awareness, sensing movement and reacting accordingly. Existing methods of measuring proprioception are limited because they rely only on the error between the knee angles, a single biomechanical parameter, and neglects timing of neural communication. This study examines an alternative method of measuring proprioceptive responses to a stimulus (motion) by using electromyogram (EMG) and electroencephalogram (EEG) signals to observe muscle and cortical brain activity. Data was analyzed to detect event-related-potentials in the EEG data associated with the platform perturbation stimulus along with the response time of muscle contraction to regain balance. This study compares proprioceptive measurements between 5 participants who have had an ACL reconstruction within the past 8 to 18 months and 5 participants without knee injuries. This measurement strategy has the potential to help physicians and physical therapists determine when a person can return to normal or strenuous activity as well as provide insight into whether uninjured patients have a proprioceptive deficit which may indicate an increased risk of injury