Ear zap device tested for arthritis hand pain

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Inclusion Criteria: * Age ≥ 18 years * Symptomatic HOA according to the American College of Rheumatology criteria * Erosive HOA according to hand radiographs performed in routine practice showing ≥1 erosive digital joint based on Verbruggen-Veys scoring definition * Hand pain level ≥ 40/100 mm on VAS at inclusion at least half of days of the 30 last days * At least ≥1 symptomatic IP joint with clinical soft swelling or erythema at inclusion * reported inadequate response or adverse effects or contraindication with existing medication (including acetaminophen, oral NSAIDs) * Informed written consent * Patient affiliated to a social security scheme NB: Clinical inflammation, ultrasound abnormalities and radiographic erosions have not have to be present in the same joint. Exclusion Criteria: * Isolated thumb-base OA (i.e., rhizarthrosis) * Predominance of the pain in the thumb base rather than digital pain * Other inflammatory joint disease (e.g. gout, reactive arthritis, rheumatoid arthritis, psoriatic arthritis, Lyme disease) * Psoriasis * Current skin disease of the left ear (e.g., eczema, urticarial lesion, skin infection, external otitis) * Ear canal not adapted to apply the auricular electrode * Known history of cardiac rhythm disturbances, atrio-ventricular block \> first degree, or total bundle branch block * Symptomatic orthostatic hypotension or repeated vasovagal syncope history * History of vagotomy * Severe Asthma * Treated sleep apnea * Existence of a pain syndrome of the upper limbs, which would interfere with the monitoring of pain * Fibromyalgia * Use of other electrically active medical devices (e.g. pacemaker, TENS for chronic pain) * Use of oral, intramuscular or intra-articular or intravenous steroids, other anti-synovial agents (e.g. slow-acting anti-rheumatic drugs such as methotrexate, sulfasalazine), intra-articular hyaluronic acid to the hand joints within the last 3 months * Any new hand OA treatment in the previous 2 months, including physiotherapy and provision of new hand splint. * Planned hand surgery in the next 3 months. * Use of any investigational (unlicensed) drug within 3 months prior to screening. * Evidence of serious uncontrolled concomitant medical condition, including cardiovascular, nervous system, pulmonary, renal, hepatic, endocrine, gastro-intestinal disease or epilepsy, which in the opinion of the investigator makes them unsuitable for the study * Pregnant or breastfeeding woman * Patient under legal protection measure (tutorship or curatorship) and patient deprived of freedom * Use of VNS before the study * Use of NSAIDs or paracetamol less than 48h before the D0 visit