Online Health Chat with Jorge Alvaro Gonzalez-Martinez, M.D., Ph.D.

July 12, 2010


Cleveland_Clinic_Host: Epilepsy is one of the most common neurological disorders, affecting up to one percent of the population in the United States. For those whose epilepsy cannot be controlled with anticonvulsant medication, there are other options available, including epilepsy surgery. Stereoelectroencephalography (SEEG) is an invasive surgical procedure that is used to identify areas of the brain where epileptic seizures originate. If you or a loved one has found no medical or surgical option for uncontrollable epileptic seizures, you may want to know more about this promising technique.

The Cleveland Clinic Epilepsy Center is one of the largest and more comprehensive epilepsy programs in the world for the evaluation and treatment of epilepsy in both children and adults. More than 300 patients with medication-resistant epilepsy undergo surgical procedures annually at Cleveland Clinic Epilepsy Center. The center is one of the few medical centers in the country that has been instrumental in using 3-D mapping to pinpoint the focus of seizures and improve surgical outcomes. The Epilepsy Center was also the first in North America, to introduce SEEG, a minimally invasive technique, which is a more precise and less invasive approach to localizing seizures.

Dr. Jorge Alvaro Gonzalez-Martinez is the epilepsy surgeon here that does SEEG. SEEG stands for stereoelectroencephalography. This involves a method of inserting electrodes into the brain to identify seizure onset and it is based on a patient's type of seizure, electrical characteristics of the seizure, and anatomy.

It is less invasive than the more widely used subdural electrode technique. Its limitations are based on the less desirable ability to map brain function. It is mainly used in patients who have non-lesion epilepsy - meaning that the brain is normal on imaging.

The main risk to the technique is bleeding during electrode insertion which is 1:100 cases.

Cleveland Clinic Epilepsy Center performs this procedure on patients 2 years of age and older.

To make an appointment with any of the other specialists in our Epilepsy Center at Cleveland Clinic, please call 216.636.5860 or 866.588.2264. You can also visit us online at www.clevelandclinic/org/epilepsy

Cleveland_Clinic_Host: Welcome to our Online Health Chat with Jorge Alvaro Gonzalez-Martinez, M.D., Ph.D. We are thrilled to have him here today for this chat. Let’s begin with the questions.

SEEG: New Epilepsy Surgical Procedure for Mapping Seizures

nicelydone: What is the SEEG?

Dr__Gonzalez-Martinez: Stereoelectroencephalography (SEEG) is an invasive surgical procedure that is used to identify areas of the brain where epileptic seizures originate. With SEEG, doctors place electrodes in targeted brain areas, which are then monitored to precisely locate seizure source. When the seizure onset is localized, a surgical resection and a good seizure outcome may be possible. In March 2009, Cleveland Clinic launched the first SEEG program in North America.

The electrodes are placed through small burr holes (2mm in diameter) that allow us to explore larger areas in the brain with minimal tissue damage. SEEG is considered to be a less invasive approach compared to other methods of invasive monitoring.

vincent: So these electrodes extend into the folds of the brain where the subdural grids can't reach. Do I have that right?

Dr__Gonzalez-Martinez: Yes - that is correct.

vincent: Is this procedure known by any other name?

Dr__Gonzalez-Martinez: No. Stereoelectroencephalography or simply SEEG.

suzee052: Are there any side effects to this procedure?

Dr__Gonzalez-Martinez: Although SEEG is considered to be a less invasive monitoring EEG procedure, it is still brain surgery and there are some risks involved.

The three main complications are: infection, bleeding and stroke. 2% of patient's who undergo the procedure will have a complication. So far in our series we had only mild complications with no clinical significance.

SEEG is a procedure that identifies where the seizures are originating. Once identified, a second surgical procedure will need to be scheduled. This usually occurs 4-6 weeks after the SEEG.

stauba: My daughter is scheduled for epilepsy surgery in Denver. Consult in Boston recommended obtaining a diffusion tensor MRI to map motor tracts. Surgeon here does not think it adds info that would impact surgery. Your thoughts?

Dr__Gonzalez-Martinez: I have the same opinion as your surgeon in Denver.

SEEG: Who is a Candidate?

markit: Does the origin of the seizure have to be known in order for a patient to be considered a candidate for surgery?

Dr__Gonzalez-Martinez: Yes. In order to identify the origin of the seizures there are a series of tests including EEG, MRI, PET and SPECT studies. If we are still unable to localize the seizures with the no invasive tests, an invasive EEG evaluation is indicated sometimes. SEEG is one of the methods of invasive monitoring.

cmasse: How young are your patients?

Dr__Gonzalez-Martinez: The age limit is 2 year-old.

cmasse: How many seizures a day does the typical candidate for this surgery have?

Dr__Gonzalez-Martinez: There is no limit for number of seizures. The main question is how debilitating are the seizures? And how many anti-epileptic drugs the patient has failed.

Dr__Gonzalez-Martinez: For example, depending on career, life seizure per month may be considered debilitating.

AWHITE: I was having about five seizures a day and no medication would work for me would it be a good candidate for the surgery?

Dr__Gonzalez-Martinez: Maybe. You will need to be evaluated by an epileptologist. At Cleveland Clinic, you may contact the Epilepsy Center directly by calling 216.636.5860 or visit the website for more detailed information at

SEEG: Evaluation & Procedure

donfluke: If you have already had all of the above tests & invasive EEG evaluations & unsuccessful surgeries, is the SEEG worth trying?

Dr__Gonzalez-Martinez: Absolutely. SEEG offers hope for patients who fail epileptic surgery and patients who have had difficulties with localizing procedures.

vincent: As a follow up to donfluke's question, how does SEEG give additional info that other surgical evaluations would not?

Dr__Gonzalez-Martinez: SEEG has the advantage to study the epileptic brain in a 3 dimensional way, analyzing the epileptic network like no other method of invasive monitoring. Patients who fail subdural grids are possible candidates for SEEG evaluation.

suzee052: Does this monitoring ever not give the expected results in locating exactly where the seizures are originating?

Dr__Gonzalez-Martinez: In 2% of our patients, we were unable to localize the seizure's origin.

donfluke: Would the RNS have to be removed in order to perform a SEEG?

Dr__Gonzalez-Martinez: Do you mean VNS. If you are referring to VNS, the answer is no - there is no need to remove VNS.

donfluke: Would the Neuropace stimulator need to be removed?

Dr__Gonzalez-Martinez: No, it would not.

vincent: Does this approach change anything about the rest of the evaluation, for instance the time spent in the epilepsy unit?

Dr__Gonzalez-Martinez: Yes - implantation time tends to be short with SEEG.

suzee052: If the patient has the procedure, then the surgery follows, what is the follow-up as far as medication, etc.

Dr__Gonzalez-Martinez: In general we maintain the medication for at least one year or more. We begin reducing the medication dosage very carefully after that.

cmasse: I am trying to understand if this surgery is the absolute last ditch surgery, or has a chance of giving patients a "normal" life.

Dr__Gonzalez-Martinez: The surgery is intended to localize the seizures and prepare the patient for a surgical resection that will have as a goal 'seizure-free.'

cmasse: If temperature and light sensitivity are triggers, I am assuming they no longer would be?

Dr__Gonzalez-Martinez: Post resection the desired outcome is no seizures even in the presence of triggers.

SEEG vs. Depth Electrodes

vincent: How is this procedure different from depth electrodes?

Dr__Gonzalez-Martinez: When we implant depth electrodes, we are implanting about probably 3-6 electrodes in standard areas in the brain. SEEG is implantation of 15-20 electrodes in several areas in the brain. SEEG is an individualized method and each patient will have a different implantation.

suzee052: I think this (SEEG) is the same procedure my son is having done, but they are removing a section of the skull instead of going through holes. Is there a reason why they would do this?

Dr__Gonzalez-Martinez: Your son is probably going through a subdural brain evaluation. Although the goals of both surgeries are the same, the method of study is different. Each patient will have a specific indication for subdurals or SEEG.

suzee052: What is the difference between this procedure and the subdural brain evaluation, or when would one be used instead of the other?

Dr__Gonzalez-Martinez: Many areas in the brain cannot be covered by subdural grids. When there is a tendency to believe that patients may have a deep source that generates seizures, SEEG is indicated.

Cleveland Clinic Outcomes & Referrals

donfluke: How many procedures have been performed at Cleveland and how many patients have been helped through it?

Dr__Gonzalez-Martinez: So far we have completed 70 SEEG procedures to date. Although our outcome is still short, 60% of these patients are either seizure free or improved significantly with seizures.

cmasse: How are neurologists learning about this treatment?

Dr__Gonzalez-Martinez: SEEG is still new in the U.S. although it has been used in Europe for more than 60 years. Cleveland Clinic Epilepsy center is organizing an international symposium in October, discussing indications for invasive monitoring, including subdural grids and SEEG.

suzee052: Do other epilepsy centers in the US refer patients to you for this procedure?

Dr__Gonzalez-Martinez: Many of our patient's are referrals from other Epilepsy Center - both in the US and internationally.

vincent: What other international centers use this approach?

Dr__Gonzalez-Martinez: Centers in Europe, mainly France and Italy. Cleveland Clinic is the only Epilepsy Center with a comprehensive SEEG program in the U.S.

VNS : Vagus Nerve Stimulation

Min68: I saw on 60 minutes that there is a new type of device similar to the VNS but it is implanted in the brain. Do you know of this product and is it in the near future that most epilepsy patients may have the chance to be recipients?

Dr__Gonzalez-Martinez: The brain stimulation for epilepsy is in the process and should be approved by the FDA shortly.

General Epilepsy Questions

mayflower1000: My mother (66 old) had a stroke about 1.5 years ago. She later had an event similar to seizure (uncontrollable shaking). Her EEG showed some abnormality. The neurologist gave her Keppra ®, saying she could take it if she has seizure again. So far, nothing has happened in the past 1 year. Will it happen again in the future? Does my mother need to do anything now? Or just wait to see if any event would happen? Would that be too late and risky? Thanks!

Dr__Gonzalez-Martinez: I would advise you to wait and follow-up with an epileptologist.

Min68: My 9 yr old's seizures were controlled on Tegretol for 7 years but then it suddenly stopped working for him. Since he has been on a combination of meds with not much help. Is it possible that Tegretol could be reintroduced with the possibility of it working for him again?

Dr__Gonzalez-Martinez: It is possible, but unlikely. It is best to discuss the next course of action with the neurologist.

Min68: If a child has epilepsy, is it best to not allow them to ride amusement park rides (Disney)? My child has never been sensitive to flashing lights. Is it only the lights to worry about or also the movement or speed of the ride?

Dr__Gonzalez-Martinez: Good question. Common sense is the best answer.

Min68: Can a person's brain become "addicted" to anticonvulsant drugs and stop working or demand more and more like it can with pain medications?

Dr__Gonzalez-Martinez: Patients may develop resistance to anti-epileptic medications.

Min68: I know some people who are on the Ketogenic diet, can this diet possibly help with a child who has known brain damage where the seizures begin or is it usually best for unexplained seizures?

Dr__Gonzalez-Martinez: Yes, this is an available option. Again, consult with the child's pediatric epileptologist.

mayflower1000: I sometimes have spasm on my legs and arms, especially when touch cold water. Is it seizure and (do I) need to be concerned?

Dr__Gonzalez-Martinez: It does not seem seizure. I would watch them and report to your epileptologist.

cmasse: Have any of these patients been Dravet Syndrome patients?

Dr__Gonzalez-Martinez: Because Dravet Syndrome is a form of generalized epilepsy, SEEG would not be a good option.


Cleveland_Clinic_Host: I'm sorry to say that our time with Jorge Alvaro Gonzalez-Martinez, MD, PhD is now over. Thank you again Dr. Gonzalez-Martinez, for taking the time to answer our questions about epilepsy.

Dr__Gonzalez-Martinez: Thank you very much. I appreciate your questions.

More Information

To make an appointment with any of the other specialists in our Epilepsy Center at Cleveland Clinic, please call 216.636.5860 or 866.588.2264. You can also visit us online.

A remote second opinion may also be requested from Cleveland Clinic through the secure eCleveland Clinic MyConsult website. To request a remote second opinion, visit