Sparrow Link Neuromodulation Device for Opioid Withdrawal Management in Hospitalized Adults With Opioid Use Disorder

Inclusion Criteria: Eligible participants must meet at least ONE of the following criteria: 1. Are continuing to experience opioid withdrawal symptoms: 1. Despite Maximal medical therapy with methadone, buprenorphine, full agonist opioids, or non-opioid medications, or 2. During tapering or detox from full agonist opioids. OR 2. Have chosen to decline methadone or buprenorphine but still require support for withdrawal symptoms and/or pain management. Additionally, participants must: * Be 18 years old or older. * Have active history of opioid use disorder. * Have a COWS score between 5-24 (Mild-moderate opioid withdrawal), indicating residual withdrawal symptoms. * Be able to provide informed consent. Exclusion Criteria: * History of or active seizure disorder. * Presence of a cardiac device (e.g., pacemaker, defibrillator). * Presence of a neurostimulator (e.g., deep brain stimulator, spinal cord stimulator). * Pregnant or lactating individuals. * COWS score ≥ 25 (Severe Withdrawal), requiring medical stabilization. * Abnormal ear Anatomy, ear Infections, or skin Conditions at Electrode Sites, including congenital malformations, post-surgical changes, significant scarring, open wounds, or hypersensitivity. * Active neurological disorders, such as traumatic brain injury, stroke, multiple sclerosis, or other conditions that may interfere with neurostimulation effects or autonomic regulation as assessed at the investigator's discretion. * Severe alcohol or benzodiazepine withdrawal that is not adequately controlled with medication, per investigator discretion. * Known or documented allergy to hydrocolloid adhesives, as evidenced in the medical record. * Evidence of active psychosis, as documented in the medical record or reported by clinical staff. * Non-English speakers, whose limited English proficiency precludes informed consent or meaningful participation in study assessments validated only in English.