Inclusion Criteria:  being a Queens WTCHP responder who agreed to be contacted to participate in research having PTSD as per DSM criteria indicated by the GRDC having elevated PTSD symptoms, indicated by a PCL-S93 score > 44 during an annual monitoring visit between 2018-2020 having a score of 33 or greater on the PCL-594 delivered during the initial phone screen to determine current symptomatology meeting diagnostic indication of PTSD using a Clinician-Administered PTSD Scale (CAPS), which is a clinical interview assessment.95  Exclusion criteria:  being physically/mentally unable to consent and participate inability to speak, read, or write in English, exhibiting any current psychotic or manic symptoms, active substance dependence, or current suicidal or homicidal intent/plan, as per the standard MINI neuropsychological assessment.96 active disease involving the auricle or ear canal (e.g., otitis media, tinnitus, infection, perforated tympanic membrane, vestibular and/or balance, excessive cerumen production, skin irritation), unwilling to remove a piercing (e.g., daith or tragus), or use a device (e.g., hearing aid, cochlear implant) that would preclude daily use of the earpiece. history of unilateral or bilateral vagotomy. Current pregnancy (self-report) previously implanted electrically active medical devices (e.g., cardiac pacemakers, automatic implantable cardioverter-defibrillators, VNS).  other major conditions, that in the judgment of the investigators/WTCHP medical staff, would make the participant unsuitable for inclusion or would interfere with the participant participating in or completing the study. these include:  current treatment with psychotropic medication, including tricyclics, antipsychotics, mood stabilizers, bupropion, barbiturates, stimulants, antiepileptics, opioid medications. current diagnosis or history of any clinically significant cardiac, endocrinologic, pulmonary, neurologic, psychiatric, hepatic, renal, hematologic, neurologic, gastrointestinal, or immunologic. history of any of the following cardiovascular conditions: Moderate to severe congestive heart failure (New York Heart Association class III or IV); Recent (within past 6 months) cerebrovascular accident, myocardial infarction, coronary stenting; Uncontrolled hypertension as defined by a confirmed systolic blood pressure > 160 mmHg or diastolic blood pressure > 100 mmHg. history of or active seizure disorder. history of recurrent vasovagal syncope episodes. diagnosis of cancer (other than non-invasive skin cancer or carcinoma in-situ of the cervix) within the 5 years prior to study entry. history of concurrent illness that requires hospitalization within 30 days prior to study entry have hypertension/hypotension uncontrolled by medication participation in another investigational trial during the 30 days prior to study entry or during this project