in epilepsy patients and has been approved for treating drug-resistant clinical depression. A noninvasive VNS device that stimulates an afferent branch of the vagus nerve is being developed and will soon undergo trials. Clinical trials have started in Antwerp, Belgium, using VNS for the treatment of tonal tinnitus after a study published in early 2011 by researchers at the University of Texas at Dallas showed successful tinnitus suppression in rats when tones were paired with brief pulses of stimulation of the vagus nerve. VNS may also be achieved by one of the vagal maneuvers: holding the breath for 20 to 60 seconds, dipping the face in cold water, coughing, humming or singing, or tensing the stomach muscles as if to bear down to have a bowel movement. Patients with supraventricular tachycardia, atrial fibrillation, and other illnesses may be trained to perform vagal maneuvers (or find one or more on their own). Vagus nerve blocking (VBLOC) therapy is similar to VNS but used only during the day. In a six-month open-label trial involving three medical centers in Australia, Mexico, and Norway, vagus nerve blocking helped 31 obese participants lose an average of nearly 15 percent of their excess weight. , a yearlong double-blind, phase II trial had begun. Vagotomy Vagotomy (cutting of the vagus nerve) is a now obsolete therapy that was performed for peptic ulcer disease. Vagotomy is currently being researched as a less invasive alternative weight-loss procedure to gastric bypass surgery. The procedure curbs the feeling of hunger and is sometimes performed in conjunction with putting bands on patients' stomachs, resulting in an average of 43% of excess weight loss at six months with diet and exercise. One serious side effect of vagotomy is a vitamin B12 deficiency later in life – perhaps after about 10 years – that is similar to pernicious anemia. The vagus normally stimulates the stomach's parietal cells to secrete acid and intrinsic factor. Intrinsic factor is needed to absorb vitamin B12 from food. The vagotomy reduces this secretion and ultimately leads to deficiency, which, if left untreated, causes nerve damage, tiredness, dementia, paranoia, and ultimately death. Researchers from Aarhus University and Aarhus University Hospital have demonstrated that vagotomy prevents (halves the risk of) the development of Parkinson's disease, suggesting that Parkinson's disease begins in the gastrointestinal tract and spreads via the vagus nerve to the brain. Or giving further evidence to the theory that