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The Ethics of Brain Stimulation to Treat Disease

The Ethics of Brain Stimulation to Treat Disease
As part of our monthly series on ethics in science and technology, we'll look at the growing practice of deep-brain stimulation to treat illnesses that range from chronic pain to Parkinson's disease.

MAUREEN CAVANAUGH (Host): I'm Maureen Cavanaugh, and you're listening to These Days on KPBS. We routinely accept the idea of surgical procedures fixing internal problems, surgery on digestive organs, blood vessels, even our hearts is, when necessary, understood to be standard medical treatment. But when the surgery is on our brain to correct a neurological condition, many of us have a different attitude. The specter of old practices like the notorious lobotomies of the 1940s are recalled with regret and fear. Despite those bad memories, a new kind of psychosurgery has been gaining acceptance in recent years. As part of our monthly series on ethics in science and technology, we’ll discuss the benefits and risks involved in the surgical technique known as deep brain stimulation. I’d like to welcome my guests. Dr. Floyd Bloom, physician and chairman emeritus of the Department of Neuropharmacology at The Scripps Research Institute and, Dr. Bloom, welcome.

DR. FLOYD BLOOM (Physician, Department of Neuropharmacology, The Scripps Research Institute): Good morning.

CAVANAUGH: And Dr. Michael Kalichman, he is neuroscientist at UCSD and founder and co-director of the Center for Ethics in Science and Technology. Michael, welcome back.

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DR. MICHAEL KALICHMAN (Neuroscientist, University of California San Diego): Good morning, Maureen.

CAVANAUGH: Now, tell us, if you would, Dr. Bloom, to start out with what is deep brain stimulation? What are we talking about?

DR. BLOOM: Well, essentially, it’s placing very fine wires, stiff wires but very fine, about the diameter of two human hairs, deep into the brain and then passing an electric current through that to activate the cells at the tip of those electrodes.

CAVANAUGH: And, indeed, does someone then have to have something else implanted somewhere?

DR. BLOOM: Well, once you’ve found the right place…

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CAVANAUGH: Right.

DR. BLOOM: …and you identify the right place by navigating the space of the brain by listening to the activity of the cells that you’re passing by, once you feel you’re in the right place, they would generally activate the electrodes to see what the result is. And then when the surgeon is absolutely certain that they’re as close to the right place as they could be, then it’s fixed to the skull and wires to the electrodes are placed under the skin, under the loose skin of the neck, to a pocket in your shoulder very much like a heart pacemaker is placed in the subcutaneous tissue of your chest. And then it can be activated by passing a magnet over it, and so you can see the results of stimulating when the battery’s active and without stimulation when the battery’s inactive without having to move the electrodes in the brain.

CAVANAUGH: And what conditions or diseases is this meant to correct?

DR. BLOOM: Well, it was first popularized with Parkinson’s disease for patients who no longer respond to their L-dopa therapy or to any of the other medications that we have. Physicians had noted that people who have the tremor of Parkinson’s disease, when they fell asleep, the tremors stopped and so they took that as a sign that someplace in the brain during sleep was allowing the tremors to stop. And so the original surgeries were to make holes in the brain to lesion the parts of the pathway that controlled the motor system. And then eventually, as much by accident as by design, they found that without having to make lesions they could achieve the same effect by stimulating the brain. And stimulating the brain medically has fewer risks and more benefits because should it go wrong in some fashion, you can always stop stimulating. But once you’ve created a hole, you can’t put it back.

CAVANAUGH: I think that’s one of the fascinating things about this to the lay person is that during this surgery, as I understand it, a person is, of course, anesthetized but is awake.

DR. BLOOM: Well, they’re locally anesthetized. They don’t feel the trauma of cutting the hole in the skull…

CAVANAUGH: Right.

DR. BLOOM: …or removing the muscle over the skull but they are awake so they can respond to the physician’s questions. They can move their arms if asked to do so. So the surgeon knows very precisely which parts of the brain they’re traversing.

CAVANAUGH: Because the placement of this is so essential.

DR. BLOOM: It’s critical. And while our brains are very roughly similar, they’re not precisely similar so it’s not just enough to take an x-ray of the skull and see where the brain is, you’ve got to really listen to the sounds of the cells that you’re passing when you put the electrode into the brain.

CAVANAUGH: Michael Kalichman, I’d like to – Some people are calling this a pacemaker for the brain, this deep brain stimulation technique. Why?

DR. KALICHMAN: Well, it’s a good question because it’s actually a misnomer. Floyd and I actually had a conversation about this before planning our program this week. The idea of pacemaker to the heart means that you are stimulating the heart to be at a regular rhythm, so you continue to stimulate and you are actually getting a direct activation with each stimulation. As I understand it, the variety of ways in which deep brain stimulation might be used could, in theory, be used in that way in some circumstances but other circumstances, equally valid, might be to actually disrupt the normal functioning of some circuits. So you might either want to stimulate or effectively inhibit, depending on the frequency of stimulation, the intensity of stimulation, the site of stimulation and the target that you have in mind.

CAVANAUGH: And it’s my understanding when someone has a pacemaker for the heart they can’t necessarily regulate it themselves but, in a sense, someone can send their own signals to their brain by running a magnet over where this…

DR. BLOOM: They can turn it on and turn it off.

CAVANAUGH: Uh-huh.

DR. BLOOM: But it’s also been used in people who are having deep brain stimulation for pain. To conserve the battery, they turn it off at night when they’re going to go to sleep and so they can do that. Now, they have not yet developed instruments that would allow the patient to adjust the frequency or the intensity. That has to be done by the doctor in charge of the operation.

CAVANAUGH: I see. Dr. Bloom, tell us a little bit more about how this technique is being used for Parkinson’s disease. What can deep brain stimulation do for a Parkinson’s patient?

DR. BLOOM: It can totally relieve the tremor and the rigidity, which are the two basic problems that a Parkinsonian patient faces every day. They can’t make purposeful movements. They have difficulty walking. They may lose their balance much more easily than other people. And the deep brain stimulation, just like throwing a switch, alleviates those symptoms.

CAVANAUGH: And what about drug therapy, though? I know that there are a lot of pills that Parkinson’s patients take. Does this replace drug therapy?

DR. BLOOM: It has been shown to reduce the requirement. For the first condition to be satisfied before having such an operation, the patient has to be losing responsiveness to their medication…

CAVANAUGH: Oh, I see.

DR. BLOOM: …to be treatment resistant.

CAVANAUGH: I see.

DR. BLOOM: And so by having the brain stimulation in effect, oftentimes they will now begin to respond to the dose that previously they were intolerant to. The thing to understand about Parkinson’s disease is the electrodes and the drugs are not treating the cause of the illness, they’re eliminating some of the symptoms that the disease causes, and so that process of getting worse continues. The longer you live with Parkinson’s disease, the more of the circuits that are missing that cause the disease will continue to be lost.

CAVANAUGH: And the idea is that the deep brain stimulation, at least symptomatically, restores some of those currents?

DR. BLOOM: Well, it replaces some of the signals that the missing nerve cells would have given to control the activity of a particular place in the motor circuits that allow the tremors to stop. The tremors are probably an adaptation to trying to – when we move our hand to a given location in space, we have both positive signals thrusting it out, and negative signals trying to keep it to the right place that we want it to go to. And when those are not synchronized, you get a tremor. You can’t move your joints properly because your muscles are contracting against each other. And so by replacing the missing chemical signals with an electrical signal in just the right place, the system is restored to a balance that the patient can then tolerate.

CAVANAUGH: And is this now an approved treatment for Parkinson’s?

DR. BLOOM: For Parkinson’s disease and for childhood dystonias, a muscle contraction disease that can’t control the involuntary movements.

CAVANAUGH: One more question about Parkinson’s disease specifically, Dr. Bloom. I read that there was a movement to get deep brain stimulation to patients earlier in their therapies so that they wouldn’t wait and – have to wait until the drugs weren’t working anymore. Are you aware of that? And do you support that idea?

DR. BLOOM: Well, since the disease continues regardless of what the therapy is, the sooner you could implement treatment that would give them the maximum benefit with the least risk, I think I would certainly favor that.

CAVANAUGH: I’m speaking with Dr. Floyd Bloom and Dr. Michael Kalichman and we’re talking about a technique called deep brain stimulation. It’s the topic of this month’s Ethics Forum, “Are We Ready for Brain Pacemakers?” It’s going to happen tomorrow night at the Reuben H. Fleet Science Center. And I want to ask – I know that in doing some reading about this, I want to ask you both about this. Let me start with you, Michael, if I can. There’ve been some strange side effects reported by Parkinson’s patients. I think this goes into the whole idea of the ethical side of this that you’re going to be talking about. What are some of those side effects?

DR. KALICHMAN: I think I’m going to leave it to Floyd to describe what those side effects might be but I will note that this is the key: You want to always ask what are the relative risks and benefits of a choice you make at every stage. And if there are side effects then you have to decide are those side effects more severe than what you’re trying to cure? In the case of Parkinson’s disease, I should note that when it gets to its most severe stages it is an extraordinarily debilitating disease. I mean, the words tremor and rigidity may sound tough but it’s extraordinarily tough. We have a situation where somebody cannot readily move and participate formally in functions that are part of what we do in normal life so it means that if there are side effects, there’s much that we’d be willing to accept.

CAVANAUGH: And what are some of those side effects, Dr. Bloom?

DR. BLOOM: Well, particularly the side effects come with increasing the dose of the medication. The missing neurotransmitter in Parkinson’s disease is called dopamine and we can replace the dopamine as long as there are dopamine nerve cells alive to manufacture it by feeding them an amino acid called dihydroxyphenylalanine, dopa. And when that’s at the right amount, it replaces what’s missing and the patient’s tremors and rigidity and balance are restored but as the nerve cells continue to die, that circuit can’t be replenished chemically. As the dose is increased, one notes a tendency towards the symptoms of overdosing with amphetamine. You can even have hallucinations. It is thought in a different chemical sense that the disease schizophrenia is the reverse of Parkinson’s disease in that it’s an excess of dopamine transmission functioning. And so one of the symptoms that Parkinsonian patients who exceed their dose limits will experience are psychoses, hallucinations, and they’re very difficult to treat.

CAVANAUGH: And I also – And there seems to be some sort of side effects involving the deep brain stimulation that almost seem to have a manic edge to them. Am I correct about that?

DR. BLOOM: Well, it’s very similar to what we were just discussing.

CAVANAUGH: Umm-hmm.

DR. BLOOM: If you are lacking the signals that dopamine gives and you can replace those with an electrical stimulation then you might expect there to be increased excitation, alertness. But one of the benefits of the stimulation, which was surprising, is that the stimulation patients sleep better at night and so instead of having the narcoleptic like symptoms that appear with some of the forms of treatment, people on dopa therapy would have sudden spontaneous uncontrollable deep sleep episodes while they’re driving their car and this kind of thing is extremely dangerous not only for the patient but everybody else on the highway with them.

CAVANAUGH: Yes, I’d say so. We’re – I’m speaking with Dr. Floyd Bloom and Dr. Michael Kalichman, and we’re talking about a psychosurgical technique that’s been called a pacemaker for the brain, although there is some controversy around – about that term. It’s being used for Parkinson’s and other diseases and conditions. I’d like to invite our audience to join the conversation. I’m wondering, does surgery for neurological conditions still hold a stigma? How would you like to see this brain pacemaker used in the future? If you have any conditions or ideas that you think that it might be useful for, give us a call, tell us what you think, 1-888-895-5727, that’s 1-888-895-KPBS. And before we have to stop for a break, Dr. Bloom, I’d like to talk a little bit more about other conditions, other neurological conditions, that deep brain stimulation is being used and tried to see whether or not it works.

DR. BLOOM: Well, it’s all still in a very experimental stage…

CAVANAUGH: Umm-hmm.

DR. BLOOM: …except for Parkinson’s disease and childhood dystonias. The other things are research topics and so there is debate as to what’s the right place to stimulate. It took a long time to find exactly the best place to stimulate for Parkinson’s disease but those circuits were known very precisely. The other things that are being considered because of the side effects that came from the patients with Parkinson’s disease whose moods improved when their brains were stimulated has been to use functional magnetic resonance imaging of the brain to look at brain activity and try to find places that are abnormal in their activity in diseases like anxiety or obsessive-compulsive disorder or epilepsy or even major depression. And those are all being experimentally investigated today with different sites and different forms of stimulation but there have been significant benefits described in these early trials.

CAVANAUGH: I’ve also read that there are some early idea that this may have some benefits for Alzheimer’s patients or for people who are in a prolonged state of unconsciousness?

DR. BLOOM: Well, the Alzheimer’s connection I would be somewhat skeptical of at the moment. I have seen the results of people in what are called minimal vegetative states who have been reported to respond, to wake up, under these conditions. They’re very special patients who have been in vegetative states in a very particular way that haven’t been responsive so far. But the alertness that we see in the patients with Parkinson’s disease when their stimulation is turned on gave rise to the idea that maybe we could wake somebody up who’s in a sleep-like comatose state. It would – It was very surprising to me to see that result. And so far it’s been a very small number of patients in whom that result has been obtained but there’s a network of academic neurosurgeons across our country who are looking for just the right cases to try to replicate this. And from that kind of examination, we’ll know whether that’s really an area of application that can be beneficial in the future.

CAVANAUGH: Let’s take a phone call. Cathy is calling from La Jolla. Good morning, Cathy, and welcome to These Days.

CATHY (Caller, La Jolla): Hi. Thanks for taking my call. I was wondering if neuropathy was something – My mother has really severe neuropathy, peripheral neuropathy, if something like this would be potentially treatment for that?

CAVANAUGH: Okay, thank you for that question. Dr. Bloom?

DR. BLOOM: Well, neuropathic pain often caused by an injury to an arm or a leg is very difficult to treat with medications but stimulators have been used for that for quite some time. They can either be peripheral nerves that are electrically stimulated or close to the spinal cord where the sensory fibers come into the spinal cord to convey the pain message to the brain have also been treated by electrical stimulation. It’s not deep brain stimulation but it is electrical stimulation. It’s the same kind of physical application but just in a different place.

CAVANAUGH: Let’s squeeze in another call before we take our break. Patrick is calling from Ramona. Good morning, Patrick. Welcome to These Days.

PATRICK (Caller, Ramona): Hi, thanks for having me.

CAVANAUGH: Yes. What can – How can we help you?

PATRICK: Well, yes, I’m wondering if and how and when this might be able to be used to help stroke victims.

DR. BLOOM: Well, it is actually part of the academic investigations that are going on now. It turns out that when brain cells are activated by electrical currents they can be stimulated to grow and to send fibers to connect to cells that they weren’t connected to before. So in the area that has survived the hemorrhage or the loss of vascular blood flow in the brain, the surrounding area might benefit from this kind of electrical stimulation and that’s one of the things that’s being looked at very seriously these days.

CAVANAUGH: We are talking about the surgical technique called deep brain stimulation and its benefits and perhaps some of its ethical challenges. We will have to take a short break. When we continue, we’ll continue taking your calls and speaking with Dr. Bloom and Michael Kalichman. Our number is 1-888-895-5727. We will return in just a few minutes here on KPBS.

CAVANAUGH: Welcome back. I’m Maureen Cavanaugh. You’re listening to These Days on KPBS. We’re talking about the technique, the psychosurgical technique, called the deep brain stimulation, about its benefits and its potential ethical problems. My guests are Dr. Floyd Bloom. He’s physician and chairman of the Department of Neuropharmacology at The Scripps Research Institute, and Michael Kalichman, neuroscientist at UCSD and founder and co-director of the Center for Ethics in Science and Technology. And we’re taking your calls at 1-888-895-5727. You know, Michael, we’ve been speaking about deep brain stimulation and we’ve been – it sounds like it has so much promise and it sounds like it’s so effective or could be so effective for so many different conditions. I wonder, what are the ethical concerns involved in using this technique?

DR. KALICHMAN: Well, if we reduce the question to why shouldn’t we use something that’s better, the answer is easy, that we should obviously do that. The challenge is to figure out what’s better and that means we’ve got two areas, two major areas I would worry about. One is, how do we do studies in the first place? What do we need to know before we stick an electrode into the brain? And the second one is what do we do with this technology once we know it works? How far are we willing to go? And both of those ethical questions hinge on the fact that the human brain is—at least I’m biased in a sense, I’m sure—but it’s one of the most remarkable structures that we know of in the universe. In such a small space, we have so much capability. And the movement disorders we talked about or the mood disorders, disorders of the mind, mean that some changes have occurred in one of the most complex organisms or structures we can imagine, and to try and repair that seems remarkable. I mean, imagine something much simpler. Any computer we have today, saying I’m going to repair the problems in my computer today by simply sticking an electrode in it and starting to stimulate. The idea we could do that in the brain is a remarkable step and it’s part of science fiction. So often we’ve seen this idea, sticking electrodes in the brain and changing behavior or movement or controlling something, so it’s both exciting and scary.

CAVANAUGH: But there’s also that stigma that I talked about at the very beginning of the brain surgery experiments that have gone on actually through the ages but most in recent memory, the idea of lobotomies to try to help people with depression and all sorts of behavioral problems and how disastrously that turned out for so many people. So is there – Do – Actually in – do surgeons and doctors actually have this kind of hesitancy in dealing with stimulating the brain or cutting the brain in any way in order to make an improvement? Dr. Bloom, let me ask you that.

DR. BLOOM: Well, I think you have to contrast what we know about the brain in 2010 with what they knew about the brain structure in 1940. Today, we can image the brain in a living person so well that it’s possible to identify exactly where you’re putting your electrode. The operations that were done that you referred to for lobotomy were done in the most crude fashion. The criteria for being qualified for that surgery were quite minimal and highly variable and operations were done without investigational studies that we have today controlling all of our clinical trials. So it’s quite a different procedure. Physicians are still quite hesitant to cut the brain and that’s why deep brain stimulation has gained a great deal of enthusiasm because, as I said a while ago, if the stimulation’s not working you can always turn the stimulator off and you really have only destroyed a very, very, very small part of the brain.

CAVANAUGH: And Michael.

DR. KALICHMAN: Yeah, I just wanted to add that in that 70 years not only has the science changed remarkably but the way we approach research studies with human subjects has changed remarkably. In the 1940s and actually for many years after that, conducting studies on humans was something that were conducted routinely often without the kind of care we have today. It’s not a guarantee that we won’t have problems but it decreases the risk greatly. Today, you have to do any of these studies under very careful scrutiny by review committees that expect substantial data before you do the study and have a great deal of concern for the understanding of the subjects before they enter the study so that they are protected in every way possible.

CAVANAUGH: We are taking your calls about the deep brain stimulation, what it may be used for and what the risks may be. The number is 1-888-895-5727. Let’s take a call from Ken, calling from San Diego. Good morning, Ken, and welcome to These Days.

KEN (Caller, San Diego): Good morning. Glad to have you take my call.

CAVANAUGH: Thank you. Yes, can we help you, Ken?

KEN: Yes. Yes, my question was about FTD and its related sub-neurodegenerative diseases. Is there any possibility with FTD to stimulate nerve cell growth in the brain could help FTD sufferers who have frontal temporal – or left anterior lobe dementia?

CAVANAUGH: Okay, first, thank you, Ken, for that question. And can you tell us what Ken is referring to?

DR. BLOOM: FTD stands for frontotemporal dementia. It’s part of the larger family of Parkinson-like diseases except that different parts of the brain circuitry are dying. As far as I know, no one has advocated trying deep brain stimulation for frontotemporal dementia treatment because we really don’t understand what circuits are involved in those cases. I’m sure people are thinking about it and the more that Parkinsonian patients – There is a very gray border in some patients’ cases between having frontotemporal dementia and having Parkinson’s disease, so it’s called Parkinsonism or Parkinson’s disease plus, that includes a larger variety of motor disorders. But the answer is not yet but possibly in the future.

CAVANAUGH: Interesting. Let’s take another call. Joshua is calling for – from Brea. I don’t know where that is. Joshua, good morning.

JOSHUA (Caller, Brea): Hi. It’s up in north Orange County. Good morning, you two. Thanks for taking my question. I was wondering, and this also has pertinence to returning soldiers, years ago I suffered a traumatic brain injury and so I have cognitive impairments residual from that. I lost a piece of my anterior temporal lobe. I was wondering because when you spoke of the strokes, you talk – you spoke of like cell regeneration unless I heard you incorrectly. So could this stimulation have an effect on those who have TBIs?

DR. BLOOM: Well, traumatic brain injury from any sort is one of the most disastrous forms of injury to our brain. The treatments being tried with deep brain stimulation for stroke are applied very shortly after the stroke has occurred. So for a person who had what our caller had several years ago, I think the chances of that kind of recovery occurring are extremely dim. But in current cases – A lot of our soldiers are coming back from the Middle East with penetrating brain injuries that otherwise would have killed them and so I feel certain that within the Department of the Army there are surgeons who are investigating all sorts of ways to help those soldiers benefit.

CAVANAUGH: Michael, in terms of using deep brain stimulation, the ethics of using deep brain stimulation, you made a comment a while ago about a new attitude toward human trials and experimenting with these techniques and people have – are more informed and monitored much better than they used to be. I wonder, however, considering that we’re talking about many illnesses that perhaps impair a person’s ability to think clearly about their course of treatment, do we run into – do you run into any ethical concerns about the use of perhaps becoming a subject for a test trial for deep brain stimulation if you’re deeply depressed or if you have another one of these neurological problems that might, you know, make it tough for you to make a decision.

DR. KALICHMAN: That’s an excellent question. In fact, so excellent you probably would be a good candidate to serve on an institutional review board to review human subject studies. This is the challenge, that if you are turning to someone who has a disorder from which there seems to be no hope and that is so debilitating, they will turn to almost anything. And explaining to that person and helping them understand that this is something that is going to be tried not because we know it works and not because we’re sure it’s safe but because we want to find out if it works and it’s safe, that’s a really tough challenge. Every one of us, whether it’s for a family member or for ourselves, if things seem hopeless, we’re willing to try anything but sometimes the things we try can be worse. In this case, the kinds of things we’re talking about, tremendous amounts of research have been done first in animal studies and then based on inferences from studies that have been done on humans to say this is a good direction to go. But until you do the studies you don’t know, and that’s the challenge for institutional review boards to think about this in each case.

CAVANAUGH: Let’s take a call. Dr. Ott is calling from Scripps. He’s a Scripps neurosurgeon. And, Dr. Ott, welcome to These Days.

DR. OTT (Caller, Scripps Physician): Thank you very much.

CAVANAUGH: Yes.

DR. OTT: I just want to mention we have a very active program in deep brain stimulation for movement disorders here at Scripps and, properly speaking, the Parkinson’s disease isn’t really psychosurgery and most of the value of deep brain stimulation is in the treatment of Parkinson’s disease but also essential tremor or familial tremor, that’s even better there, another wonderful application. In terms of psychosurgery itself, recent advances have been the use of this in the treatment of depression. Andres Lozano from Toronto published a series of those recently. More than half the patients had benefit. These were patients who didn’t respond to medications. Obsessive-compulsive disorder, several large series of those patients have been published, useful there. And then there’s some rare psychosurgery rage attacks, a group from Milan, in people with rage and other – cluster headache, that sort of thing. So it has many uses, and I think the – in terms of the issue of the bioethics, it really bears, as the commenters have been talking about, on the ability for us to obtain informed consent from people who are somehow mentally challenged by depression or dementia.

DR. BLOOM: We should add that there is no evidence that people with depression have lost any cognitive capacity, so in contrast to something like schizophrenia or Alzheimer’s disease where there is a great deal of loss of cognitive capacity, if we can explain it properly to a person in an emotional state of depression, they have the right and the capacity to make that decision for themselves.

CAVANAUGH: Well, thank you for calling in, Dr. Ott. Thank you for explaining that for us. Let’s take another call. Melissa is calling in Poway. Good morning, Melissa, and welcome to These Days.

MELISSA (Caller, Poway): Good morning. I was calling because I’ve been living with MS, multiple sclerosis, for almost ten years and I’m one of the fortunate ones that hasn’t been, you know, grossly debilitated by it but I know that there are several cases of people that have been. I’m wondering how this could apply to patients living with MS.

DR. BLOOM: I think there’s very little room for it to be applied in multiple sclerosis because that disease has lesions all over the brain to start with. It’s also a disease that comes and goes as the brain tries to heal itself. So knowing where you could put the electrodes to do something that might simulate growth factors, I think, right now is well beyond the capacity. But people with MS shouldn’t be disappointed because we now have more medications to treat multiple sclerosis than there has ever been before and many of them are extremely effective in what they can do.

CAVANAUGH: And in the – Michael, in the debate between people who look to pharmacology for solutions to brain illnesses as opposed to deep brain stimulation, you made a point earlier I thought was very useful in that there is less potential for side effects if the deep brain stimulation is placed properly and is working properly.

DR. KALICHMAN: Yes, so that’s actually key to this question about something like MS or other disorders that might involve many different brain areas. With deep brain stimulation, we’re talking about placing electrodes in one very specific site in the brain or perhaps a couple of sites but not an array of electrodes throughout the brain. So when you can be specific about your site, either through electrical stimulation or even with a drug where you can topically place the drug in one specific location, then you can decrease the chances of side effects, where you’re going to get side effects from a widespread use of the drugs throughout the body.

CAVANAUGH: Well, we’ve just about run out of time here but I want to let everyone know that you can explore this topic more at a forum tomorrow night at the Reuben H. Fleet Science Center. It’s the Exploring Ethics forum and it’s called “Are We Ready for Brain Pacemakers?” It’s Wednesday at 5:30 at the Reuben H. Fleet Science Center. The event is free and open to the public. You can go to KPBS.org/TheseDays for more information or to post your comments about this segment. Dr. Bloom and Michael Kalichman, thank you so much for your time today.

DR. BLOOM: Thank you.

CAVANAUGH: And thank you very much for listening. Be sure to join us tomorrow morning at 10:00 for Governor Arnold Schwarzenegger’s last State of the State address. We’ll broadcast the governor’s speech, bring you local analysis, and take your phone calls. That’s tomorrow morning starting at 10:00 right here on KPBS-FM. You’ve been listening to These Days on KPBS.