and information processing, memory and emotion. ETS patients are being studied using the autonomic failure protocol headed by David Goldstein, M.D. Ph.D., senior investigator at the U.S National Institute of Neurological Disorders and Stroke. He has documented loss of thermoregulatory function, cardiac denervation, and loss of vasoconstriction. Recurrence of the original symptoms due to nerve regeneration or nerve sprouting can occur within the first year post surgery. Nerve sprouting, or abnormal nerve growth after damage or injury to the nerves can cause other further damage. Sprouting sympathetic nerves can form connections with sensory nerves, and lead to pain conditions that are mediated by the SNS. Every time the system is activated, it is translated into pain. This sprouting and its action can lead to Frey's syndrome, a recognized after effect of sympathectomy, when the growing sympathetic nerves innervate salivary glands, leading to excessive sweating regardless of environmental temperature through olfactory or gustatory stimulation. In addition, patients have reported lethargy, depression, weakness, limb swelling, lack of libido, decreased physical and mental reactivity, oversensitivity to sound, light and stress and weight gain. (British Journal of Surgery 2004; 91: 264–269) Risks ETS has both the normal risks of surgery, such as bleeding and infection, conversion to open chest surgery, and several specific risks, including permanent and unavoidable alteration of nerve function. It is reported that a number of patients - 9 since 2010, mostly young women - have died during this procedure due to major intrathoracic bleeding and cerebral disruption. Bleeding during and following the operation may be significant in up to 5% of patients. Pneumothorax (collapsed lung) can occur (2% of patients). Compensatory hyperhidrosis (or reflex hyperhidrosis) is common over the long term. The rates of severe compensatory sweating vary widely between studies, ranging from as high as 92% of patients. Of those patients that develop this side effect, about a quarter in one study said it was a major and disabling problem. A severe possible consequence of thoracic sympathectomy is corposcindosis (split-body syndrome), in which the patient feels that they are living in two separate bodies, because sympathetic nerve function has been divided into two distinct regions, one dead, and the other hyperactive. Additionally, the following side effects have all been reported by patients: Chronic muscular pain, numbness and weakness of the limbs, Horner's Syndrome, anhidrosis (inability to sweat), hyperthermia (exacerbated by anhidrosis and systemic thermoregulatory dysfunction), neuralgia, paraesthesia, fatigue and