Transcutaneous Vagus Nerve Stimulation (tcVNS) in JIA (AJA01)

Inclusion Criteria: Participant is 5 through 18 years of age (inclusive) at screening. Regarding informed consent and compliance: If 5 through 6 years of age, the participant's guardian is willing and able to understand and provide informed consent and comply with study protocol. If 7 through 17 years of age, the participant is willing and able to sign assent and comply with study protocol, and the participant's guardian is willing and able to understand and provide informed consent and comply with study protocol. If 18 years of age, the participant is willing and able to understand and provide informed consent and comply with study protocol. The participant has a Juvenile Idiopathic Arthritis (JIA) diagnosis meeting International League of Associations for Rheumatology (ILAR) classification criteria with one of the following subtypes: rheumatoid-factor negative polyarthritis rheumatoid-factor positive polyarthritis persistent oligoarthritis extended oligoarthritis psoriatic arthritis enthesitis-related arthritis systemic arthritis The participant has >=3 joints with active arthritis at screening If the participant is receiving therapy for JIA at screening, that therapy is stable for the time period outlined below and is expected to remain stable for the duration of the study: a. stable dose for at least 1 week prior to screening: i. Oral steroids, <= 0.2 mg/kg/day with a maximum 10 mg/day dose b. stable dose for at least 8 weeks prior to screening i. adalimumab ii. anakinra iii. canakinumab iv. certolizumab pegol v. etanercept vi. golimumab vii. infliximab viii. leflunomide ix. methotrexate x. tocilizumab c. stable dose for at least 12 weeks prior to screening: i. abatacept If a female of child-bearing potential, the participant has a negative urine pregnancy test at screening If of reproductive potential, must agree to abstinence or effective methods of birth control for the duration of the study Exclusion Criteria: Participant has been treated for JIA with more than 2 therapies, other than NSAIDs or intra-articular injections, with lack of efficacy. Participant has received high-dose steroids (>=0.2 mg/kg/day) within the 28 days prior to screening. Participant has had active systemic disease (fever, systemic rash) within the 3 months prior to screening including any of the following lab manifestations at screening: Ferritin >1000 ng/mL White blood cell (WBC) ≥15,000/mm^3 Participant has had an active acute infection within 2 weeks of screening. Participant has a history of arrhythmia. Participant has been diagnosed with postural orthostatic tachycardia syndrome (POTS). Participant has received an intra-articular cortisone injection within the 28 days prior to screening. Participant has received treatment with an investigational drug or device during the 28 days prior to screening or within five half-lives of the investigational drug prior to screening/baseline, whichever is the greater length of time. Participant has received chronic treatment with an anti-cholinergic medication, including over the counter medications. Participant has received treatment with rituximab: Within one year of screening At any time previously without documented B cell repletion Participant has a comorbid disease that has required treatment with corticosteroids within the past year. Participant has an implantable electronic device such as a pacemaker, defibrillator, hearing aid, cochlear implant, insulin pump or deep brain stimulator. Participant has used cutaneous vagus nerve stimulation within 12 weeks prior to screening. Participant has received a live attenuated viral vaccine within 28 days prior to screening or is expected to receive one during the study. Participant has any condition which, in the opinion of the investigator, would jeopardize the participant's safety following exposure to a study intervention. Participant has any past or current medical problems or findings from a physical examination or laboratory testing that are not listed above but which, in the opinion of the investigator, may pose additional risks from participation in the study, may interfere with the participant's ability to comply with study requirements, or may impact the quality or interpretation of the data obtained from the study.