Ultrasound Neuroimmune Modulation in Adults With Rheumatoid Arthritis

Inclusion Criteria:

* At least 18 years old
* Diagnosis of rheumatoid arthritis as defined by ACR/EULAR 2010 classification criteria
* At least moderate disease activity, defined as ≥4 tender joints (28-joint count) and ≥4 swollen joints (28-joint count) and a DAS28-CRP \>3.2 at the baseline visit
* hsCRP \> 0.3 mg/dL at the last qualifying visit, baseline or retest
* If on background DMARD therapy, must be on stable dose (see exclusion criteria)
* Able and willing to comply with all study-related procedures, including daily treatment sessions in the study vehicle, research site visits, and assessments

Exclusion Criteria:

* Unable to provide informed consent
* Current or planned participation in another interventional clinical trial
* Inflammatory joint disease other than RA (including but not limited to gout, systemic lupus erythematosus, psoriatic arthritis, axial spondyloarthritis including ankylosing spondylitis and non-radiographic axial spondyloarthritis, reactive arthritis, overlap connective tissue diseases, scleroderma, polymyositis, dermatomyositis. Current diagnosis of secondary Sjogren's Syndrome is permitted.
* Prior use of \>2 biologic or targeted synthetic DMARDs for RA where the primary reason for discontinuation was efficacy
* Conventional synthetic DMARDs:

  * Initiation within 12 weeks prior to enrollment
  * Dose adjustment or discontinuation within 4 weeks prior to enrollment
  * If on a stable dose, inability to maintain the stable dose during the study period
* Biologic DMARDs:

  * Initiation or dose adjustment within 12 weeks prior to enrollment
  * Discontinuation within 4 weeks prior to enrollment
  * If on a stable dose, inability to maintain the stable dose during the study period
* JAK inhibitors:

  * Initiation, dose adjustment, or discontinuation within 4 weeks prior to enrollment
  * If on a stable dose, inability to maintain the stable dose during the study period
* Corticosteroids:

  * Initiation, dose adjustment, or discontinuation within 4 weeks prior to enrollment
  * Current dose \>10 mg/day prednisone (or equivalent)
  * If on a stable dose, inability to maintain the stable dose during the study
* NSAIDs:

  * Initiation, dose adjustment, or discontinuation of high-dose NSAIDs (≥1200 mg/day ibuprofen) within 14 days of informed consent. Over-the-counter use of NSAIDs is permissible.
* Pregnant or planning to become pregnant during the study period
* Known hypersensitivity to ultrasound gel or membrane components
* History of splenic disorders, including splenectomy, congenital asplenia, or splenomegaly on baseline visit ultrasound
* Rash, wound, or skin infection overlying the spleen
* History of vagal nerve injury, vagotomy, or known autonomic neuropathy
* Recent abdominal surgery or trauma within 30 days of screening
* Skin to spleen hilum depth \>7 cm as measured by ultrasound at the baseline visit
* Abdominal anatomy or condition precluding adequate ultrasound targeting of the spleen
* Uncontrolled fibromyalgia or other diffuse pain syndromes that may confound symptom reporting
* Any condition that, in the investigator's judgment, would preclude safe participation or compliance with study procedures