for depression in some countries), alertness and quality-of-life are increased significantly within the first year of vagus nerve stimulation. vns patients can induce an extra stimulation themselves with a vns magnet when they noticed that a seizure is approaching and it has been shown that the majority of seizures can be interrupted this type of on-demand stimulation. the procedure to implant a vagus nerve stimulator is very safe: no case of death related to vns implantation surgery has ever occurred. infection of the tissue pocket in which the generator is located that requires antibiotic treatment occurs in around 3% of patients. the most common side effect is hoarseness or change in voice. headaches and shortness of breath are less common. in most cases, side effects only occur during activity of the stimulation (mostly every 3 to 5 minutes) and reduce over time. in most cases vns does not replace antiepileptic medication. patients must continue their antiepileptic medication however in many cases the dose can be reduced over time so that patients experience fewer side effects of the medication. the battery of the vns generator can depending on the model and the settings can last between 3 and 10 years. vns with cardiac-based seizure detection in 82% of epilepsy patients the heart rate increases quickly and suddenly upon a seizure this is known as ictal tachycardia. ictal tachycardia is so characteristic that it can be distinguished from the slow gradual increase of heart rate that occurs during physical activity. this way in the majority of epilepsy patients seizures can be detected in the ecg. in addition to classical vns, some new vns generators continuously monitor heart rate and identify fast and sudden heart rate increases associated with seizures with intelligent software. then an automatic additional stimulation can be triggered to interrupt, prevent or alleviate the seizure. this new generator type was shown to detect and treat at least four out of five seizures and 60% of seizures were shown to be interrupted with this heart-rate triggered stimulation. the earlier in the course of the seizure the stimulation occurred the quicker the seizure ended generally seizures were shown to be reduced by around 35% by stimulation diets for over 100 years it has been known that a diet with a high fat content and a low carbohydrate content can reduce seizures. radically curbing carbohydrate intake imitates starvation and forces the body to draw energy from ketone bodies that form when fat is metabolized instead of drawing its energy from sugar. this state is called ketosis and it changes several biochemical processes in the brain in a way that inhibits epileptic activity. on this basis there are several diets that are often recommended to children under 12 years old, but are also effective in adults. ketogenic diet in europe the ketogenic diet is the diet that is most commonly recommended by doctors for patients with epilepsy. in this diet the ratio of fat to carbohydrates and proteins is 4:1. that means that the fat content of the consumed food must be around 80%, the protein content must be around 15%, and the carbohydrate content must be around 5%. for comparison the average western diet consists of a carbohydrate content of over 50%. after one year on the ketogenic diet the success rate (seizure reduction over 50%) is between 30 and 50% and the dropout rate is around 45%. although the ketogenic diet can be very effective some families report that it's not compatible with daily life on the long run because it's too restrictive as bread pasta and sweets are forbidden in the ketogenic diet. in puberty with increasing autonomy it can be difficult for adolescents to follow the diet strictly. for this reason a fat ratio of 3: 1 instead of 4: 1 can be recommended to make meals more palatable. side effects of the ketogenic diet can be constipation, tiredness and after a long term diet, in one out of 20 patients, kidney stones. mct-ketogenic diet in the 1960s it was discovered that when medium-chain triglycerides (mct) fats are metabolized in the body more ketone bodies are produced then from metabolizing any other fat. based on this mechanism the mct ketogenic diet a modification of the ketogenic diet was developed and it has nearly replaced the classic ketogenic diet in the usa. in the mct ketogenic diet mct oil is added to ketogenic meals, which allows the carbohydrate content to be increased to around 15 to 20%. this way some patients find the meals more enjoyable. the success rate of the mct ketogenic diet does not differ from the classic ketogenic diet however not all children can tolerate the necessary large amounts of mct oil which is also very expensive. modified atkins a modified atkins diet describes the long term practice of the first phase of the popular atkins diet the so-called induction phase to reduce seizures through ketosis. in this diet the fat content of the nutrition is slightly lower than in the ketogenic diet at around 60%, the protein content is around 30% and the carbohydrate content is around 10% rendering the diet less restrictive and more compatible with the daily life compared to the ketogenic diet. several studies show that the modified atkins diet produces a similar or slightly lower seizure reduction to the ketogenic diet. some physicians, especially in the us, recommend the modified atkins diet because they assume that patients will adhere to it on the long-term because it is more compatible with daily life and the meals are more enjoyable. it has also been concluded in another study that the diet is well tolerated and effective in hard to treat childhood epilepsy. other deep brain stimulation of the anterior nuclei of the thalamus is approved for dre in some countries in europe, but has been and continues to only be used in a very few patients. after 5 years of dbs a seizure reduction of 69% and a 50%-responder rate of 68% was reported in a randomized-double blinded trial. the rate of serious device related events was 34% in this study. responsive neurostimulation (rns) is approved for dre in the us and involves stimulation directly to 1 or 2 seizure foci when abnormal electrocorticographic activity is detected by the devices software. after 2 years of rns a seizure reduction of 53% was reported in a randomized-double blinded trial as well as a rate of serious device related events of 2.5%. transcutaneous vagus nerve stimulation (tvns) is approved for dre in some european countries and involves externally stimulating the auricular branch of the vagus nerve in the ear. tvns failed to demonstrate efficacy in a first randomized-double blinded trial: responder rates did not differ between active and control groups potentially indicating a placebo effect behind the 34% seizure reduction seen in the patients who completed the full follow-up period.