I have generalized tonic-clonic seizures. My EEG shows that the electrical activity does not start at one point in the brain and spread, but occurs on both sides of the brain at once. Would I be a good candidate for an RNS?
At this time, only patients who have focal onset seizures, 1 or 2 foci, are candidates for the study. It might be that in the future, people with generalized seizure onsets might be candidates for this therapy.
The VNS has been around since the nineties and has been implanted in over 30,000 patients. It is well studied and effective for many people. Why would I want to consider an RNS as opposed to the VNS?
VNS is indicated for patient in whom we do not know where the seizures are coming from, have more than 2 foci or have generalized onset seizures. Thus, the indications for using VNS or RNS are very different at this time.
How do you find the specific point on the brain at which to place RNS leads? Is an EEG or regular MRI sufficient?
In order to determine where the seizures are originating in the brain, we do EEG, MRI and occasionally PET studies. If the non-invasive studies can not give us the answer, we sometimes introduce (implant) the EEG electrodes into or placed on the surface of the brain, to capture the seizures and investigate whether we can find the focus or foci. This requires a surgical procedure and observation in the hospital for 7 to 10 days.
Once you have received a VNS, Cyberonics recommends that you not have any further MRIs as the strong magnetic field could heat up the leads wrapping around the Vagus nerve. As an MRI is required to determine the locations to place RNS leads, could a person with a VNS have an RNS implanted?
A person with a RNS generally should not have a MRI scan of the brain because the device creates so much artifact that the information given by the scan is often useless. Also, the MRI may cause heating of the leads. If an imaging procedure is necessary, x-ray based technologies such as a CT scan should be used whenever possible. Hopefully, future RNS devices will be MRI compatible.
The study website indicates that the leads & electrodes are implanted in the brain and that the neurotransmitter is placed in the skull. When you say “in the skull”, does that mean in the cavity with the brain or under the scalp?
The device is embedded in the skull and does not go into the brain. It is then covered by the muscle, fat and scalp and is therefore not visible. The EEG electrodes do go into and/or sit on the surface of the brain and therefore are under the skull.
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If you have epilepsy and are interested in finding out if you are a good match for the RNS clinical study, Call: 1-866-904-6630 or go to: www.seizurestudy.com