Understanding the Effects of Transcutaneous Auricular Neurostimulation for Treatment of Chronic Pain

The purpose of the study is to find out how a stimulation device worn on the ear works. This device is thought to stimulate nerves in the area around the ear to change the signals in the brain. The device has been shown to reduce pain and to reduce the symptoms of withdrawal. The investigator will also investigate changes in the way each participant perceive sensations of pressure and heat. The participant will be asked to reduce the amount of pain medication that they take. Then, the participant will spend several days and nights in the Clinical Research Center at UTMB (University of Texas Medical Branch) in Galveston. During that time, the participant will be monitored for withdrawal symptoms and will receive either active (e.g., "real") brain stimulation or sham (e.g., "fake") brain stimulation for two days (four hours each day). At two times over the course of the study (before and after ear stimulation treatment), the participant will complete questionnaires about their pain score and how they are feeling, sensory testing, and will undergo magnetic resonance imaging (MRI) of their brain. The investigator will collect the following information from the participant's medical record: age, gender, medication history, medical diagnoses, recent vital signs, past doctor visits or hospital stays, and results of urine drug tests. Participation in this study will last approximately four days, and the participant will stay in the Clinical Research Center.

Inclusion Criteria: * Males and females between 18 and 65 years of age * Participant is able to provide informed consent and function at an intellectual level sufficient for study requirements * Presence of pain on more than half of the days in the last six months * Must have proof of prescribed medication by either showing a prescription bottle with the individual's name or the presence of a prescription on the Prescription Drug Monitoring Program (PDMP) * Willingness to taper opioid dose by at least 10% * Patient or provider requests opioid dose reduction or discontinuation. * Urine Drug Screen (UDS) must be positive for their prescribed opioid * Urine Drug Test must be negative for illicit drugs, benzodiazepines, and nonprescribed opioids * Must agree to use nicotine patches and/or gum instead of smoking or vaping in the UTMB facilities Exclusion Criteria: * Currently receiving treatment for cancer * Participant has a history of epileptic seizures * Participant has a history of neurological diseases or traumatic brain injury * Participant has abnormal ear anatomy or current ear infection present * Participant has presence of devices, e.g., pacemakers, cochlear prosthesis, neurostimulators * Currently receiving a prescription benzodiazepine medication * Current prescription opioid dose \>50 MME/day * Current abuse of illicit drugs or alcohol (nicotine use is acceptable). * Surgery within the previous month * Report of suicide attempt or psychiatric hospitalization in the past 10 years. * Current suicidal ideation with specific plan or intent * Women of childbearing potential not using adequate contraception as per investigator judgment or not willing to comply with contraception for the duration of the study * Females who are pregnant or lactating * Participant has any other significant disease or disorder which, in the opinion of the Investigator, may either put the participants at risk because of participation in the trial, or may influence the result of the trial, or the participant's ability to participate in the trial