| Vagus Nerve Stimulation for Chronic or
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| | have to do anything. Because there is
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| Treatment-Resistant Depression
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| | nothing to remember, compliance is
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| About Vagus Nerve Stimulation
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| | assured. The stimulation is not supposed
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| VNS is not related to brain surgery,
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| | to be uncomfortable, and some patients do
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| although it is a treatment that affects
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| | not even feel the stimulation. A nurse at
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| the function of the brain. Vagus Nerve
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| | the doctor's office can adjust the level
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| Stimulation uses specific stimulation of
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| | of stimulation (amount of electricity
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| the vagus nerve to send stimulation to
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| | delivered) if the patient ever feels
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| specific parts of the brain that are
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| | uncomfortable. In the study currently
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| involved in mood. It is not like
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| | being reviewed by the FDA, researchers
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| Electro-Convulsive Therapy (ECT), a
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| | noted several similarities between
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| treatment that involves stimulation of
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| | epileptic and depressed patients (note
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| the entire brain and induces convulsions
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| | 4).
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| in patients. In fact, patients may not
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| | One of the most important similarities is
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| even feel the stimulation from VNS since
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| | that Vagus Nerve Stimulation treatment
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| the vagus nerve does not have the type of
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| | efficacy improves over time. The longer
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| nerves that carry pain signals. Nor does
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| | the patient receives stimulation, the
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| VNS interfere with drugs, and patients
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| | better the results. In addition, both
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| having Vagus Nerve Stimulation can
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| | populations of patients share the
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| continue taking their other drugs without
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| | following:
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| worrying about side effects or
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| | Assured adherence to treatment regimen
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| interactions between drugs.
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| | Safety of the procedure
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| On July 15, 2005, the FDA approved vagus
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| | Safety of the therapy
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| nerve stimulation as a treatment for
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| | High continuation rates
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| chronic depression.
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| | No drug interactions
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| What Is the Vagus Nerve?
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| | What Is the Surgery Like?
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| Vagus means "wandering" in Latin, and is
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| | Vagus Nerve Stimulation is NOT brain
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| the perfect description for the vagus
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| | surgery, even though it is an invasive
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| nerve, the longest nerve in the body. It
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| | surgical procedure that changes the
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| averages almost two feet in length and
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| | function of the brain. The stimulator is
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| "wanders" throughout the upper body. The
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| | a pacemaker-like device that generates
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| vagus nerve starts in the brain, goes
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| | electrical pulses (Pulse Generator); it
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| down the neck and into the body where if
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| | is implanted under the skin in the left
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| affects the vocal cords, the acid content
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| | chest through a small incision. While
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| of the stomach, the heart, the lungs, and
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| | this may sound like a serious or
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| other organs. In the brain it projects to
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| | dangerous procedure, it is not. The FDA
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| areas believed to be responsible for
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| | has approved the use, and confirmed the
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| seizures, mood, appetite, memory and
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| | safety of this procedure, and 22,000
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| anxiety (note 3). However, the vagus
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| | patients have received the implant to
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| nerve cord does not have many pain
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| | treat epilepsy. The Vagus Nerve
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| nerves, so stimulation of the vagus nerve
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| | Stimulation surgery involves two small
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| is not painful, although some patients
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| | incisions, one in the chest and one at
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| may feel some sensation when electrical
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| | the lowest part of the neck. At no time
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| pulses are generated.
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| | is the brain physically manipulated by
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| The History of Vagus Nerve Stimulation
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| | the surgeon.
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| Vagus Nerve Stimulation has been used to
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| | The surgery to implant the NCP System
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| treat epilepsy patients for years; the
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| | takes 45 minutes to two hours. Local,
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| first human clinical trial was in 1988
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| | regional or general anesthesia (putting
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| (note 1), and the FDA approved VNS
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| | the patient to sleep) is used during the
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| therapy for epilepsy in 1997 (note 2). So
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| | surgery; the doctor and anesthetist
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| far over 22,000 people worldwide have had
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| | determine which type of anesthesia is
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| VNS therapy (note 3), and it has proven
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| | best for each patient. Most Vagus Nerve
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| to be a safe and effective treatment for
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| | Stimulation patients will have outpatient
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| epilepsy. These patients have reported
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| | surgery, (note 3) but some patients may
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| minimal side effects, which have tended
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| | need to stay in the hospital overnight,
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| to decrease over time. The efficacy of
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| | and in that case they will need a family
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| the treatment has also been shown to
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| | member or companion to take them home
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| increase with longer treatment time (note
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| | from the hospital.
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| 1).
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| | What Happens After the Vagus Nerve
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| When Vagus Nerve Stimulation was first
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| | Stimulation Surgery?
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| approved for epilepsy, some patients
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| | Most Vagus Nerve Stimulation patients go
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| reported an improvement in mood.
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| | home the same day or the next day. You
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| Researchers decided to design a study
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| | will feel some minor stiffness/soreness
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| specifically to measure changes in a
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| | around the area of the implant for a few
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| patient's mood and depression due to
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| | days. Your doctor may prescribe a minor
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| stimulation of the vagus nerve. In 1999,
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| | pain medication such as Tylenol with
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| scientists began the first open label (no
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| | codeine. A week later your surgeon will
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| placebo group) study for depression with
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| | probably want to check the scars and a
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| 60 patients. This first study found that
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| | nurse can program/change the settings on
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| there was indeed an improvement in mood
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| | the stimulator in the doctor's office.
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| for depressed patients. Based on this
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| | Is the Vagus Nerve Stimulation Surgery
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| study, a more detailed and thorough study
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| | Final?
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| was designed to determine if Vagus Nerve
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| | The Vagus Nerve Stimulator can be turned
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| Stimulation would be a safe, tolerable
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| | off or removed (explanted) at any time if
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| and effective treatment for chronic
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| | the patient feels that it is not helping,
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| depression.
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| | or in the unlikely event that the patient
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| The recently completed one-year, double
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| | can't tolerate the stimulation. The
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| blind, placebo controlled trial had 235
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| | device can be completely turned off in
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| patients from 21 participating hospitals
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| | less than 30 seconds in the doctor's
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| in the United States, and showed
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| | office, all it takes is for a nurse to
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| clinically significant improvements due
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| | hold a programmable wand over the skin
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| to treatment compared to baseline (note
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| | above the Pulse Generator. Explantation
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| 2). The acute (short-term) phase lasted
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| | (removal) of the Vagus Nerve Stimulation
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| three months, during which half of the
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| | device is also possible, however, less
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| patients received stimulation (treatment
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| | than one half of one percent of the
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| group) and half did not (control group).
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| | 22,000 patients have elected to have the
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| The long-term phase of the study lasted
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| | device removed. As for implantation, the
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| an additional 9 months (for one year
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| | surgery to remove the device is a very
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| total treatment) of stimulation. The
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| | simple procedure. Only the Pulse
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| HRSD-24 (24 item clinician-rated Hamilton
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| | Generator is taken out of the body;
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| Rating Scale for Depression) improvements
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| | attempting to remove the electrode from
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| observed over the first year were highly
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| | around the vagus nerve could cause
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| significant. The results of this
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| | damage, and is not recommended.
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| long-term, pivotal study were submitted
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| | References
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| to FDA in October 2003; the FDA's
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| | 1. Pharmacoresistant Epilepsy and VNS
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| decision on the use of Vagus Nerve
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| | Therapy. September 24, 2003 presentation
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| Stimulation for depression is not
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| | by J.W. Wheless, MD. The University of
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| anticipated before October 2004 (note 2).
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| | Texas Health Science Center, Houston TX,
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| Of note, Vagus Nerve Stimulation therapy
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| | USA.
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| was approved for use in patients with
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| | 2. Form 10-Q for Cyberonics Inc,
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| treatment resistant depression in the
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| | September 4, 2003.
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| European Union in March 2001, and in
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| | 3. Vagus Nerve Stimulation Therapy
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| Canada in April 2001 (note 2).
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| | Mechanisms of Action. September 24, 2003
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| How Does Vagus Nerve Stimulation Therapy
| |
| | presentation by M.S. George, MD. Medical
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| Work?
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| | University of South Carolina, Charleston,
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| The Pulse Generator (battery) delivers a
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| | SC, USA.
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| small amount of electrical current to the
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| | 4. The Investigation of Vagus Nerve
|
| vagus nerve intermittently (30 seconds on
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| | Stimulation Therapy in
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| and five minutes off) (note 3) 24 hours a
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| | Treatment-Resistant Depression. September
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| day, 7 days a week for up to 10 years.
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| | 24, 2003 presentation by R.L. Rudolph,
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| The stimulation is delivered
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| | MD. Cyberonics, Inc.
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| automatically, so the patient does not
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| |
|
