Dr. Andres M. Kanner, MD, FAAN, FANA, FAES, the Chief of the Epilepsy Division and Professor of Clinical Neurology at the University of Miami Miller School of Medicine talks about epilepsy and how a new device is helping slow down seizures.
Interview conducted by Ivanhoe Broadcast News in December 2017.
A lot of people have heard of it but it’s not always something you’re born with. What is epilepsy?
Dr. Kanner: Epilepsy is a relatively common condition that affects the central nervous system and that consists of the occurrence of seizures. What is a seizure? A seizure to put in to a very simple concept is a short circuit in the brain. Imagine the brain is a super computer. It is a very sophisticated computer. The computer chips are in the gray matter and the cables are in the white matter of the brain. When you have a seizure in the brain you’re having a short circuit involving one of the multiple circuits that exist in the brain. And depending on the circuit that is affected the clinical expressions of the seizures will vary. So when people think of seizures they imagine an individual having a convulsion. That is when they become stiff and then they start shaking in all four extremities and they foam at the mouth and then they become unresponsive for a period of time. This happens when there is a short circuit that involves the entire brain and that leads in to this type of seizure. There are other short circuits that affect a specific area of the brain. Let’s say for example, the temporal lobe where the short circuit causes certain symptoms like fear, panic, or sensation of Deja vu or a sensation in the stomach, after which they can lose awareness of their surroundings and be unresponsive and they don’t know what’s happening around them.
Let’s talk a little bit more about the different types of seizures. Most people think of grand mal seizures or they think of the convulsion, but there are other seizure types.
Dr. Kanner: Right. There are different types of seizures and depending on what part of the brain is affected by the short circuit the seizure will present in a different manner. Some of the seizures can be very short and just consist of motionless staring and unresponsiveness. And those are what we call absence seizures, they affect the whole brain. They’re very typical in young children and they have a benign course and they respond to medication. In sixty to seventy percent of these children, they go away when they become adolescents. There are other seizures where they may have the same phenomena of motionless staring but it’s much longer in duration and then they can have purposeless movements of the mouth and the hands. They can last between forty five seconds and two minutes. And these type of seizures have a focal onset in a discreet area of the brain where the short circuit begins. And it may propagate to different areas of the brain and when that short circuit occurs the patient is not aware of what’s going on around him. When that short circuit spreads then to the whole brain then the individual can have a full convulsion. And that’s what people often conceptualize as a seizure. These seizures obviously are a big obstacle for any individual to lead a normal life because they cannot perform many activities. They cannot drive, and obviously when they have convulsions, they can hurt themselves, they can have fractures and they can have concussions. And these seizures interfere with their quality of life in a very significant way.
Are more people living today with that epilepsy than before? Are you seeing a higher prevalence?
Dr. Kanner: If you look at the prevalence of epilepsy in the United States for example, and you decide to investigate how many people today in the city of Miami suffer from epilepsy, the prevalence rates will range between 0.6 percent and 0.9%. But if you look at the lifetime prevalence in a population where people would be expected to live up to the age of eighty the prevalence would be about three percent of the population. So you’re talking about a condition that is relatively frequent. And the interesting observation that has been made is that as people live longer the incidence of epilepsy increases. So somebody who is seventy years old has a higher risk of developing epilepsy than somebody at the age of thirty. The good news for when you have seizures beginning after the age of sixty is that they may have a more benign course and they may be more likely to respond to treatment than seizures that begin at the earlier age. In general about sixty to seventy percent of people with epilepsy will respond to medication which is the initial treatment of the seizure disorders. But thirty to forty percent of people will continue to have seizures despite trials with several antiepileptic medications at optimal doses. What are we doing with those people? We basically try to see if there are alternative treatments. So the next alternative option that we tried to investigate is the possibility of surgery. Now for somebody to be a candidate for surgery you need to be able to identify where the seizure activity is originating from in the brain. You need to make sure that, that area where the seizure is coming from can be safely removed. Otherwise these people would not be a candidate for a surgical procedure. What can we expect of surgery in people who have seizures coming from the temporal lobe and the activity is only located in inner structures of the temporal lobe, a condition known as mesial temporal sclerosis which is a condition that was very frequent cause for epilepsy that did not respond to medication. Seventy percent of these people when they underwent epilepsy surgery became seizure free. Now unfortunately not everybody can be a candidate to a surgical treatment where you would resect the area of the brain that’s generating the seizure activity.
Like Mark?
Dr. Kanner: One of the cases is Mark. In Mark’s case, he had undergone epilepsy surgery after he had failed to respond to medication. But unfortunately after a period of time he started to have seizures coming from contralateral side of the brain. You cannot operate both sides of the brain. And that often happens in patients where we cannot offer resective surgery when seizures are coming from both sides of the brain and / or when seizures are coming from areas of the brain that process important functioning, like language, motor, sensory functions, vision and so in those cases you have to consider other types of therapy. One of those therapies is what we have been using at our center and throughout the United States: Responsive Neurostimulation, which is a very interesting treatment that is based on the use of a device, a stimulator that you can imagine it as a pacemaker which has a computer chip embedded in it. That computer chip in the stimulator are connected to the parts of the brain that are generating the seizure activity. We can have up to two electrodes that can connect to the areas of the brain that are generating seizures. And for example, when seizures are coming from the left and right temporal region one electrode goes to the left temporal lobe the other one to the right temporal lobe. That computer chip is then programmed to detect this specific pattern of the seizure activity for each side because sometimes the patterns of the seizure activity in each side, in one side may be different than that of the other side. So you’re able to program the detection of the specific seizure activity for each focus. And then the device as it detects the beginning of that abnormal pattern sends an electrical stimulation and during the process of the programming of the computer chip we also program the device to send stimulation and we tweak the parameters of the stimulation until we find the optimum stimulation parameter. That the optimum parameters for the stimulation which may be different from one patient to another or maybe even different from one side and the other.
Would it stop the seizures from happening? In other words would it stop it before it started?
Dr. Kanner: The idea is that the moment the abnormal electrical activity begins, it sends an electrical stimulation that prevents it from evolving in to a seizure. That’s the basic idea. Now the treatment is such that it takes time for the efficacy to become apparent. Because you have to be changing the parameters used for the detection of the seizure activity and the effective stimulation over time. But what has been found is that the rate of percentage of patients where there is a decrease in seizure frequency increases over time. So the first year it may be thirty, forty percent of patients who notice a decrease in seizure frequency by more than fifty percent. By the seventh year it has been noticed they were up to sixty to seventy percent of patients where there is a decrease in seizure frequency by more than fifty percent. It is not considered to be a curative treatment because the majority of the patients are going to continue to have seizures. But there have been already about ten to fifteen percent of patients who have gone for at least a year without having seizures.
It is really helping their quality of life?
Dr. Kanner: It’s a treatment modality that if surgery is not an option for you, you want to see if this can be an alternative. The device has been tested with respect to its impact on cognitive functions. And what it has found is that even though you’re doing stimulation in the deep structures of the brain there is no deterioration in memory or language functions when you’re stimulating the language dominant hemisphere. In patients with temporal lobe epilepsy where memory was affected and the source was in the deep structures of the temporal lobe that processes memory such as the hippocampus formation there has been evidence of some improvement in memory processing in some of these patients. When language is affected and the source of the seizure activity is in the language area in the temporal lateral neocortex, language functions have also been improving in some of these patients. But there has been no evidence that there has been deterioration in these cognitive functions. And so at this point this is a device that is appearing to be safe and so far the data looks promising as far as providing an alternative to the patient. The other advantage of this device is that because it’s recording every time the patient has a seizure we can tell exactly how many seizures the patient is having, at what time and at what time of the day and what time of the month. That’s important because if we for example find that the person is having most of their seizures at night we could change the way they take their medication by giving them a higher dose of the medication before they go to bed. Seizures often can come in cycles and for example, in women, seizures can be associated with their menstrual cycle. And so by recording the seizures, you can tell exactly the relationship between the seizure occurrences and their menstrual cycle and their ovulation. And that can allow the clinician to adjust the medication at certain times of the month where they can change the dose of medication for example before the menstrual period or around the time of ovulation.
This does seem to be a very promising advancement in treating.
Dr Kanner: Not only in treating but also in understanding epilepsy. Because now with this device that is implanted we are recording in a continuous manner every time the patient has a seizure. So it’s giving us an understanding of how do seizures occur in the brain of individuals and because many of these seizures are not seizures that express themselves clinically. For every clinical seizure we’re identifying an average of eight what we call electrographic seizures. Those are seizures that we’re identifying in the recordings with the neuro stimulator device and one of them becomes clinical which tells us that an individual is having more seizure activity or more abnormal electrical activity than he or she are aware of. And that will allow us to understand better how does this abnormal electrical activity impact on cognitive function for patients as well as on the changes in mood and anxiety that are so prevalent in people with epilepsy.
END OF INTERVIEW
This information is intended for additional research purposes only. It is not to be used as a prescription or advice from Ivanhoe Broadcast News, Inc. or any medical professional interviewed. Ivanhoe Broadcast News, Inc. assumes no responsibility for the depth or accuracy of physician statements. Procedures or medicines apply to different people and medical factors; always consult your physician on medical matters.
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