Brain-Computer Interface Visualization Training to Optimize Muscle Activation Following Orthopaedic Surgery

1. Introduction

Background

Patients recovering from orthopedic surgical procedures require a comprehensive physical rehabilitation process to help recover pre-operative functional mobility and strength.

A limiting factor in physical rehabilitation is a patient's inability to activate the involved muscle groups postoperatively, a phenomenon termed Arthrogenic Muscle Inhibition (AMI) \[1, 2\]. AMI is a complex neurological process where the injury or surgery disrupts sensory and motor neurological pathways, resulting in decreased muscle activation and strength. AMI can be a major obstacle to a patient's return to normal mobility and muscular function \[2\]. For example, patients who have undergone anterior cruciate ligament reconstruction (ACLR), may experience ineffective quadriceps activation and persistent hamstring contracture, leading to loss of passive and active range of motion (ROM). Even with standard physical therapy rehabilitation, patients with AMI have ineffective recovery due to decreased muscular activation and movement dysfunction \[3\].

Visualization training with neurofeedback therapy (NFVT) is a non-invasive method that could be used with standard post-operative physical rehabilitation to decrease AMI and help patients recover pre-operative functional mobility and strength.

The motor regions of the brain (motor cortex) play a crucial role in planning, controlling, and executing voluntary movements. The motor cortex is not only active during actual movement; mentally rehearsing motor acts without physically moving also activates the motor cortex \[4\]. For example, one could imagine themselves performing squats without squatting (visualization), this process activates the brain regions related to squatting. Such visualization training can enhance the brain's ability to plan, control and execute movement without physical load on the body \[5\]. Theoretically, this training could help restore disrupted neurological pathways, leading to reduced AMI and improved patient recovery after surgery \[6\].

When a brain region has heightened activity, passive sensors on the scalp can detect the increased electrical activity, this technique is known as electroencephalography (EEG). A computer can process the EEG signal and provide users with real time feedback on their concentration level and whether they are activating their motor cortex through mental visualization of movements (neurofeedback). This feedback process enhances the visualization training \[6\].

This study aims to investigate the effect of visualization with neurofeedback on postoperative recovery in patients undergoing physical rehabilitation from 4 orthopedic surgical procedures: anterior cruciate ligament reconstruction (ACLR), total knee arthroplasty (TKA), total hip arthroplasty (THA), and hip arthroscopy (HA) for femoroacetabular impingement syndrome (FAIS). More specifically, neurofeedback training will be implemented using a novel technology developed by i-BrainTech™.

The findings of this study have the potential to revolutionize physical rehabilitation protocols for patients, offering a novel approach that integrates visualization therapy with neurofeedback to enhance standard physical rehabilitation. This could lead to faster, more complete recoveries, and potentially mitigate the long-term impacts of AMI. The successful application of this technology would also help deepen current understanding of neuroplasticity, specifically the malleability of the neuromuscular pathways and how this can improve motor control.

Purpose

The purpose of this study is to investigate the effect of NFVT on postoperative recovery in patients rehabilitating from orthopedic surgeries.

Hypothesis

It was hypothesized that through targeted NFVT using i-BrainTech™, post-surgical participants will experience improved muscle activation, which in turn will contribute to better rehabilitation outcomes, strength, such as range of motion, and functional mobility. We also hypothesize that these improvements seen throughout the recovery period will have a positive impact on short-term patient-reported outcome surveys (PROs). 2. Methods

Settings \& Locations

Conducted at Rush University Medical Center, specifically within: * The main campus of Midwest Orthopaedics at Rush (MOR) Sofija and Jorge O. Galante Orthopedic Building, 1611 W Harrison St, Chicago, IL 60612 * Motion Laboratory in the MOR Orthopedic Building * Physical therapy facility (Chicago location) 3. Interventions

Control group: Standard post-surgical rehabilitation therapy Intervention Group: Standard post-surgical rehabilitation therapy + i-BrainTech neurofeedback training * Procedure: Patients use EEG-based neurofeedback twice a week until 8 weeks post-operatively. * Neurofeedback setup: EEG cap monitors motor cortex activation, guiding visualization exercises * Training sessions: Patients visualize movements, and EEG feedback helps optimize motor activation

Physical Therapy

Patients will follow a standard physical therapy protocol. The protocol will be assigned by their respective surgeon who conducted the procedure and will be specific to the procedure that the patient underwent. The standardized physical therapy protocols will be attached in supplemental materials.

Treatment Group Intervention:

The main study intervention for the treatment group involves NFVT using the i-BrainTech™ Platform.

This is a technology that uses electroencephalography (EEG) to read the electrical activities in the brain \[7\]. Active neurons in the brain causes change in electrical activities on the scalp, detectable by electrodes placed on the scalp. The sensing electrodes are completely passive, incapable of sending electrical current to the wearer. An EEG cap will be used with sensing electrodes aligned to the frontal cortex and the motor cortex. The detected electrical activity from these locations of the scalp will transmitted to the computer, which allows for assessment of focus and motor cortex activity \[8\]. There are multiple cap sizes to ensure a comfortable fit.

By concentrating and imagining themselves performing the rehabilitation movements (visualization), patients activate their own motor and pre-frontal cortices. The EEG sensors detect the increased brain electrical activity, and the i-BrainTech™ software translates the EEG signal into a virtual avatar figure performing such movements on a computer monitor, providing feedback to the patients on their visualization efforts (neurofeedback). Patients will effectively play a video game using their own brain signals. By turning this feedback process into a video game, the i-BrainTech™ platform provides an incentive for the user to intensely focus and visualize the rehabilitation exercises, and in the process activate and strengthen the neural pathways responsible for these rehabilitation movements. The repeated activation of neural pathways theoretically improves their muscle control and reduces AMI \[6\].

Instruction to Participants (how to play the "game")

The i-BrainTech™ training station has a laptop and EEG caps. Participants will be seated in front of the laptop and put on the appropriately sized EEG cap. A conductive gel is injected into 2 insertion points on the cap. The column of gel touches the participant's skin on one side and the sensor on the other. The gel is water-soluble and dries up in chunks and is not sticky. The conductive gel is routinely used in the clinic and pre-operative area for ultrasound. The wet gel can be wiped off with a paper towel and the dried gel can be pulled off the participant's scalp as it does not stick to hair. The remaining fragments will be washed away when the patient showers.

The session will be started and the i-BrainTech™ software will provide on screen prompts and feedback to the user.

First is a 2-minute calibration period. During this time, the user is prompted to relax their mind so baseline brain activity may be detected. The brain activity above the baseline is used to control the cartoon avatar performing rehabilitation exercises.

After calibration, a 20-minute NFVT session begins. Participants are prompted to imagine themselves performing various rehabilitation exercises (visualization). The selections of exercises are the rehabilitation exercises they will eventually perform at a physical therapy session, specific to their surgical procedures (Table 1). The software provides real time feedback on how concentrated the user is with the task, and how well the user is at visualizing the specific therapy exercises. The video game incentivizes participants to concentrate on the visualization therapy to maximize their score.

When the participant finishes the i-BrainTech™ training session, they will remove the EEG cap and move on to their standard-of-care physical therapy session. 4. Clinic Flow and Timing of Assessments

Participants in the intervention group will perform virtual rehabilitation exercises for 20 minutes 2 times per week for the first 8 weeks postoperatively.

Approximately 45 minutes total is required for setup, calibration, virtual rehabilitation, and clean up.

After the virtual rehab session, patients in the intervention group will move on to their standard-of-care PT session based on the surgeon's protocol specific to their operation. Patients in the control group go directly to their standard PT session.

The intervention group will spend an additional 45 minutes in clinic to perform the i-BrainTech™ training session for a total study visit time of no more than 1-1.5 hours.

The control group will spend 45 minutes to 1 hour of total study visit time.

Participants will continue receiving their standard clinical care with their attending healthcare team throughout the study. In addition, they will attend scheduled study visits at the Motion Laboratory in the Orthopedic Building at Rush University Medical Center for motion analysis and physical testing at 2 months, 4 months, and 6 months post-surgery.

At each visit, anthropometric data (age, height, and weight) will be collected first. Participants will then change into standardized clothing provided by the research team.

Surface Electromyography (sEMG)

sEMG data will be collected from five muscles: rectus femoris, vastus medialis oblique, vastus lateralis, semitendinosus, and biceps femoris, using a research-grade sEMG system. Electrode placement will follow the SENIAM (Surface EMG for a Non-Invasive Assessment of Muscles) protocol.

Per SENIAM (www.seniam.org) guidelines, the skin will be shaved, lightly abraded with abrasion wipes, and cleaned with alcohol wipes before electrode application. Electrodes will be placed at least 2 cm apart to minimize crosstalk, and voluntary contractions will be performed to confirm correct placement.

Each muscle will be assessed individually before data collection. Once all sensors are verified, simultaneous sEMG and 3D kinematic data collection will be performed using Qualisys Track Manager software or similar.

Motion Capture

• Joint Kinematics During Functional Tasks (Walk, Lunge, Bilateral Squats, Single Leg Vertical Jump) [Срок оценки: 2, 4 and 6 months]
• Joint Kinetics During Functional Tasks (Walk, Lunge, Bilateral Squats, Single Leg Vertical Jump) [Срок оценки: 2, 4 and 6 months]
• EMG Amplitude of Lower Limb Muscles During Functional Tasks [Срок оценки: 2, 4 and 6 months]
• Flexibility [Срок оценки: 2, 4 and 6 months]
• International Knee Documentation Committee (IKDC) Subjective Knee Form [Срок оценки: Pre-operative, 2, 4 and 6 months, 1 year, 2 years]
• Knee and Hip Strength [Срок оценки: 2, 4 and 6 months]
• Area Under the Curve of Muscle Activation During Functional Tasks [Срок оценки: 2, 4, and 6 months]
• Torque Curves of Hip and Knee During Flexion, Extension, Abduction [Срок оценки: 2, 4 and 6 months]
• Knee Injury and Osteoarthritis Outcome Score for Joint Replacement (KOOS Jr) [Срок оценки: Pre-operative, 2, 4, and 6 months; 1 year; 2 years]
• Veterans RAND 12-Item Health Survey (VR-12) [Срок оценки: Pre-operative, 2, 4, and 6 months; 1 year; 2 years]
• Patient-Reported Outcome Measurement Information System - Pain Interference (PROMIS-PI) [Срок оценки: Pre-operative, 2, 4, and 6 months; 1 year; 2 years]
• Patient-Reported Outcome Measurement Information System - Physical Function (PROMIS-PF) [Срок оценки: Pre-operative, 2, 4, and 6 months; 1 year; 2 years]