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.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
OTHER
Masking
SINGLE
Enrollment
50
Participants receive trial-by-trial feedback of flexor withdrawal reflex amplitude.
Participants receive sham trial-by-trial feedback of flexor withdrawal reflex amplitude. The placebo condition is matched on instrumentation, session structure, stimulation triggering, and visit burden, and differs in stimulation intensity and in whether displayed feedback derives from the participant's own reflex.
Incidence of adverse events
Number of participants with at least one adverse event and total event count, characterized by nature, severity, relationship to study procedures, and timing. Serious adverse events reported separately.
Time frame: Enrollment through 14 days after the final intervention session (approximately 6 weeks)
Number of participants completing the intervention protocol
Participants completing all 6 intervention sessions, as a proportion of those randomized. Reasons for discontinuation recorded.
Time frame: Randomization through final intervention session (approximately 4 weeks)
Percentage of scheduled intervention sessions attended
Sessions attended as a proportion of sessions scheduled, across all randomized participants.
Time frame: Intervention period (approximately 3 weeks)
Adherence to the intervention protocol
Proportion of prescribed conditioning stimulations completed per session (225 across 3 blocks of 75), and sessions completed without protocol deviation.
Time frame: Intervention period (approximately 3 weeks)
Participant-reported acceptability of the intervention
Survey ratings of usefulness, ease of use, and burden, with identification of most and least helpful components and reasons for non-completion.
Time frame: Week 2, Week 3, and Week 5
Screening and enrollment yield
Number screened, number eligible, number enrolled, and number declining, with reasons for ineligibility and declination.
Time frame: Duration of recruitment (approximately 30 months)
Change in flexor withdrawal reflex amplitude
Rectified EMG reflex amplitude during conditioning blocks expressed relative to the within-session 25-stimulation baseline, and change across the 6 sessions.
Time frame: Week 1 through Week 3
Pain severity
Knee pain rated on a visual analog scale.
Time frame: Week 1, Week 3, and Week 5
Pressure pain threshold
Algometry at the patellae and wrist.
Time frame: Baseline (Day 1), then Week 1 through Week 3
Temporal summation of pain
Change in pain rating across repeated weighted pinprick stimuli.
Time frame: Baseline (Day 1)
Pain-related evoked potential (PREP) amplitude
Peak-to-peak amplitude of pain-related evoked potentials.
Time frame: Baseline (Day 1)
Somatosensory-evoked potential (SSEP) amplitude
Peak-to-peak amplitude of somatosensory evoked potentials.
Time frame: Baseline (Day 1)
Short-afferent inhibition
Conditioned motor evoked potential amplitude expressed relative to unconditioned response.
Time frame: Baseline (Day 1)
Conditioned pain modulation
Change in pressure pain threshold during cold water immersion.
Time frame: Baseline (Day 1)
Difference in pain intensity between experimentally evoked and real-world movement-evoked pain
VAS rating following the weight-bearing stimulation protocol minus rating following a participant-selected pain-provoking activity. Unit: mm on a 0-100 visual analog scale.
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Time frame: Baseline (Day 1)
Difference in WOMAC pain subscale score between experimentally evoked and real-world movement-evoked pain
VAS rating following the weight-bearing stimulation protocol minus rating following a participant-selected pain-provoking activity. Unit: units on a scale, 0-20
Time frame: Baseline (Day 1)
Difference in SF-MPQ-2 total score between experimentally evoked and real-world movement-evoked pain
VAS rating following the weight-bearing stimulation protocol minus rating following a participant-selected pain-provoking activity. Unit: units on a scale 0-20.
Time frame: Baseline (Day 1)
Change in KOOS Pain subscale score
Knee Injury and Osteoarthritis Outcome Score. Unit: units on a scale, 0-100, higher indicating fewer symptoms.
Time frame: Baseline (Day 1), Week 3, and Week 5
Change in ICOAP total score
Intermittent and Constant Osteoarthritis Pain. Unit: units on a scale, 0-100.
Time frame: Baseline (Day 1), Week 3, and Week 5.