Survivors of severe brain injury, such as lack of oxygen or severe traumatic brain injury, frequently experience Paroxysmal Sympathetic Hyperactivity (PSH). PSH is characterized by disabling symptoms such as a fast heart rate, high blood pressure, rapid breathing, rigidity, tremors, and sweating due to uncontrolled sympathetic hyperactivity in the nervous system. Effective treatment is necessary to decrease secondary brain injury, prevent weight loss from increased metabolic demand and reduce suffering. Currently, a combination of medications to slow down the sympathetic nervous system, muscle relaxants, anti-anxiety drugs, gabapentin, and narcotics are used to treat PSH. The sudden, recurrent attacks of PSH often require repeated rescue medications and multiple drugs with a high risk of side effects. Non-drug treatments for PSH may revolutionize treatment. The novel and non-invasive Percutaneous Electrical Nerve Field Stimulation (PENFS) device is an attractive and potentially effective treatment option for PSH. PENFS, applied to the external ear, has been shown to be effective for conditions such as abdominal pain, narcotic withdrawal, and cyclic vomiting syndrome, all which have similar symptoms to PSH. Therefore, the hypothesis is PENFS could be effective in the treatment of PSH. The electrical current delivered by the PENFS device is thought to increase parasympathetic activity by stimulating a branch of the vagus nerve. PENFS was shown to decrease central sympathetic nervous system activity by 36% within 5 minutes of being placed in the ear of a rat model. Similar central inhibition could improve symptoms of PSH. This pilot study aims to evaluate the feasibility of performing an efficacy trial of PENFS for children with PSH.