Eligibility Criteria:
Study subjects
Inclusion Criteria:
* Kellgren-Lawrence Grade \>= 3
Exclusion Criteria:
* Inflammatory arthropathy (e.g., rheumatoid arthritis), BMI \>=35
Control subjects:
Exclusion Criteria:
* Complaints of lower extremity joint pain
* Known diagnosis of knee osteoarthpathy
* Prior history of knee surgery, knee injections, or injury to knee joints (e.g., meniscus tears, ligamentous injuries), BMI \>=35
Both groups, exclusion:
* Subjects with chronic heart problems, including, but not limited to, chronic hypertension, heart palpitations, a weak or irregular heartbeat, or a previous heart attack,
* Subjects taking the following drugs within 12 hours of the experiment or during the experiment: caffeine, alcohol, psychoactive drugs, nicotine or marijuana, other recreational drugs, and medicine of any kind that is not normally taken daily. Such medications include;
* NSAIDs
* Acetaminophen
* Steroidal anti-inflammatory agents
* Bronchodilators
* Appetite suppressants
* Lipase inhibitors
* Women who are currently pregnant
* Subjects with Raynaud's syndrome
* Subjects with any of the following conditions: active skin lesions where EDA sensors are, vertigo or dizziness, and anyone with postural orthostatic tachycardia syndrome (POTS), peripheral neuropathy, seizure disorders, methicillin-resistant staphylococcus aureus (MRSA), impaired circulation, medical implants, open skin lesions, chronic eczema on hands where EDA and electrical stimulator's electrodes are attached, diabetes, and epilepsy.
* Participants who have a skin sensitivity to metals, have a pacemaker or defibrillator, or have recent head trauma within the past two weeks (even without loss of consciousness)
* Participants who cannot feel physical pain or have a history of self-harm