Inclusion Criteria:  Male or female, 18-80 years of age Ruptured aneurysmal SAH confirmed by angiography and repaired by neurosurgical clipping or endovascular occlusion (coiling) Modified Glasgow Coma Scale (mGCS) score ≥ 12 within 72 hours of presumed aneurysm rupture Enrollment and initiation of nVNS treatment must occur within 72 hours of presumed aneurysm rupture Provide a legally obtained informed consent form from the participant or the legally authorized representative (LAR); telephonic consent is acceptable Female participants of reproductive age must have a negative pregnancy test result (urine or blood)  Exclusion Criteria:  Use of any concomitant electrostimulation device, including a pacemaker, defibrillator, or deep brain stimulator No plan to secure aneurysm, defined as aneurysm that has not been surgically or endovascularly treated Previous neck dissection or radiation History of carotid artery disease or carotid surgery/dissection History of secondary or tertiary heart blocks, ventricular tachycardia, or supraventricular tachycardia (SVT; including atrial fibrillation) Screws, metals, or devices in the neck Currently participating in an investigational drug or device clinical trial with potential to confound data collection