Neurofeedback for Pain Sensitization in Knee Osteoarthritis

The goal of this clinical trial is to learn whether a training method called neurofeedback is safe and practical to use in people with knee osteoarthritis (knee OA). Neurofeedback uses a computer screen to show people their body's responses as they happen, so they can learn to change those responses. The response being trained in this study is a protective reflex in the leg. This reflex is often stronger than normal in people with knee OA, which may be a sign that their nervous system has become more sensitive to pain. The main questions this study aims to answer are: 1. Is this training safe, and what side effects do people have? 2. Can people with knee OA complete the training, and do they find it acceptable? Researchers will compare people who receive real neurofeedback training with people who receive a placebo (inactive) version of the training. In the placebo version, the electrical pulses are too weak to trigger the reflex, and what appears on the screen is not based on the person's own reflex. Comparing the two groups helps researchers tell which parts of taking part are difficult because of the study set-up itself and which are difficult because of the training. Participants will: * Visit a research laboratory at Northeastern University in Boston 7 times: one measurement visit lasting about 3 hours, then 6 training visits lasting about 60 to 90 minutes each. Training visits happen about twice a week, with at least 2 days between visits. * At the measurement visit, have small sensors placed on the head and legs, receive brief electrical pulses to the leg and brief magnetic pulses to the head, and have their sensitivity to pain checked using brief pressure on the kneecaps and wrist. * At each training visit, receive brief electrical pulses to the leg while watching a screen. People in the neurofeedback group will try to make a bar on the screen smaller. People in the placebo group will watch a screen that does not reflect their own reflex. * Answer questionnaires about their knee pain and daily activities. * Receive a phone call and complete a short online survey about 2 weeks after the last training visit. A smaller group of participants will take part in the measurement visit only. They may not receive neurofeedback or placebo training.