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Dr. Nora Volkow to discuss JAMA paper, "Effects of Cell Phone Radiofrequency Signal Exposure on Brain Glucose Metabolism"

February 22, 2011

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Coordinator: At this time all participants are in a listen only mode. If you muted your own line, please un-mute your phone as your lines were automatically muted when you joined today's call. After the presentation we will conduct a question and answer session. To ask a question, please press star 1. And today's conference is being recorded. If you have any objections you may disconnect at this time. And now I'd like to turn the meeting over to Dr. Nora Volkow. Ma'am you may begin.

Dr. Nora Volkow: Yes, hello, good afternoon. First of all thanks for your interest on this paper. It has been a very exciting story for us at Brookhaven National Laboratory.

And what we turned out to do - was the purpose of the study - was to try to find out if the human brain is sensitive to the weak electromagnetic signals that are emitted from cell phones.

And what we showed in this study was that indeed it is. The human brain is sensitive to the electromagnetic radiation that is emitted from cell phones. And we found this out because we observe a significant increase in glucose metabolism in the areas of the brain that were closest to the antenna.

And because the brain uses glucose when it's activated, we interpret this to mean that the electromagnetic waves in the brain were activating the cells. And that's why we're observing the increases in glucose metabolism, which again were limited to the areas that were close to the antenna.

And areas that were far away showed no evidence of changes. So to us, the significance of this is highlighting the importance now to try to understand whether this type of activation, which by itself should not – we don't expect it to have any harmful effects.

But the question that remains to be studied into the future is - could there be potential long-term consequences from repeated stimulation as, for example, people use their cell phones for 10, 20, 30 years and for long periods of time?

And we don't know whether there are or there are not. But the fact that the human brain is sensitive to this type of electromagnetic radiation really highlights the relevance to investigate this question that of course has generated a lot of interest in the public.

So I – this is the main findings of the study. And, as reiterated, in our conclusion at this point, we do not know what the clinical significance of this particular finding is, both with respect of potential therapeutic effects of this type of technology but also of potential negative consequences from cell phone exposure.

We – based on these studies we cannot speak on with respect to these consequences. So I'd rather at this point open it up for questions. So since that will allow you to very much try to get explanations for things that may not be very obvious in the way that the press release was written.

Coordinator: All right. And if you would like to ask a question, please press star 1. You will be prompted to record your name. Please un-mute your phone and state your name slowly and clearly.

Once again it's star 1 to ask a question, one moment please. We do have a question coming in, one moment please. Okay, our first question comes from Carolyn Beeler from WHYY Public Radio. Your line is open.

Carolyn Beeler: Hi, thank you for taking my question. So you said this does not, you know, give you any clinical explanation for connection of cell phones and cancer. But does it sort of - does it advance that conversation at all?

Or I guess were you – how does it add to that conversation? And where do you go from here, I guess?

Dr. Nora Volkow: Well unfortunately our finding does not enlighten in any way this controversy of whether cell phone exposure produces or does not produce cancer.

What it does say to us is that the human brain is sensitive to these electromagnetic radiation. That it is sensitive. Whether these had any negative consequences in the way that it's affected or not, that is something that needs to be properly evaluated.

If we had not seen any changes if – because actually we powered this study in order to be able to detect small effects. So had we not seen an effect of cell phone exposure, it would have much - been much easier to dismiss any concern about potential negatives of cell phones because if they didn't – we didn't – observe any effect after 50 minute exposure then it would have been much less likely that chronic exposure would produce any changes. But the fact that we are observing changes really highlights the need to do the studies to be properly able to answer the question of whether cell phone exposure could have harmful effects or not. Because it may be that it doesn't have any harmful effects.

In which case, actually one of the interesting potentials that are brought by these studies – there are no evidence of harmful effects - is could one use for example this type of technology to activate areas of the brain that may not be properly activated? And explore potential therapeutic applications of this type of technology.

But that will require that one shows that there are no untoward effects. There is really an urgent need to try to address this question.

Carolyn Beeler: Thank you.

Coordinator: Next we have Jeff Evans from Clinical Neurology News. Your line is open.

Jeff Evans: Hi. I was wondering if you could tell us what the two brain areas that were mentioned in the paper that increased in brain metabolism - what those actually do?

And if they – if any other studies have looked at other types of stimulation of those brain areas and what they might be, you know, therapeutic, what therapeutic possibilities there might be if for those, for any sort of disorders involved in those areas of the brain?

Dr. Nora Volkow: No, not at the areas of the brain that were activated in our study were activated on the basis of a unique characteristics of the cell phone, where the antenna is located.

So the antenna location can vary from one model to the other. As well as the position that you have of the cell phone with respect to the head. So for our study, the antenna was in the lower part of the cell phone, which is the area closest to the mouth.

And if you look at it, if you think about it three dimensionally, the area closest to the brain, or the area of the brain closest to that, the mouth, is the area that is on top of your eyes which corresponds to the orbital frontal cortex.

So not surprisingly, that's where we actually observe the largest changes in metabolism, in the orbital frontal cortex, I mean the most anterior parts of the temporal pole.

Now had we used another cell phone, like for example in the past, particularly, most of the cell phones had the antenna on the upper part. And you – they even had a little antenna.

And that – therefore the antenna was very close to the ears. In that case, the area of the brain that would be activated would be close to the auditory cortex because it is the brain that is underlying the ears.

And then the effects would have been very different. For our type of technology therefore the area of the orbital frontal cortex actually is an area that is highly connected with limbic areas of the brain and plays a very important role in determining the value of reinforcers. And a reinforcer – so a reinforcer is something that we actually value and motivates our behavior.

But that value is dependent on the context. And this is very easily exemplified for example with food. When we're very hungry, the value of food is much greater than when we are satiated.

And the area of the brain that is involved with assigning values is the orbital frontal cortex. So it's therefore not surprising that if you damage this area of the brain for example, animals will eat compulsively, and the value of food is not degraded. It's also curiously an area that is also has been now more recently shown to be involved with social behaviors. And there was a very important study, the one of Gage on a paper done by Damasio in Science in which he [recreates the accident of] this man whose orbital frontal cortex was destroyed while working on setting up the tracks for the railroad. And there was a rod that passed and destroyed his orbital frontal cortex.

And this man who had been extremely responsible with his work, after the accident, became completely unreliable and spent a significant part of his life in prison.

So even though his intellectual abilities had not been disrupted, he actually – his social skills were very much damaged.

So, and again we did not go into great detail about what would we expect from specific activation of this area of the brain. Because we are very aware that the area that may – that will receive the greatest absorption of these RF radiation – will be very much dependent on the cell phone utilized.

And so we didn't want to just concentrate on our particular finding because it may – it will be relevant with respect to significance on behavior to the particular cell type utilized.

Jeff Evans: Okay thank you.

Coordinator: One moment, another question came in. Now we have Laura Sanders from Science News. Your line is open.

Laura Sanders: Hi, thanks for taking the question. I'm wondering if it seems like electromagnetic radiation from cell phones might actually be stronger when you're talking on it.

So I'm curious if you think this might be an underestimation that you found in your paper? And might the effect be greater in just everyday normal use of cell phones?

Dr. Nora Volkow: Yes. No that is absolutely correct. And it's a very pointed question. And we're very aware that indeed the transmission may be stronger when you're speaking then when you are just receiving.

And – but the problem with actually addressing that –we didn't want to have the subjects image while they were speaking because that would produce a pattern of activation that could confound the signal that were purely a reflection from the deposition of these electromagnetic radiation.

But it is correct. Your assumption is correct. That it may have been an underestimation based on the way that cell phones are normally used where you are not just silently listening to the other, but actually are activating the cell phone by transmitting information.

Laura Sanders: And then one more question. If you had any recommendations for people to limit this electromagnetic radiation, what would they be?

Dr. Nora Volkow: Well my recommendation is for those individuals that want to play it safe because there is the uncertainty about whether this could have or not deleterious effects.

Or whether you're very sensitive, as is my case – I don't like my brain to be stimulated by anything that is not physiological. There's a very easy solution without having to give away the use of cell phones, which are extraordinary.

And which is – use your cell phone in such a way that it's far away from your head. So how do you do that? Just use it in speakerphone mode. That's one. You can also use an earpiece that is wired to the cell phone.

And that way the cell phone will be one foot away from you. And at that distance, the electromagnetic radiation will have, based on what we know, very unlikely to have any effects on the brain.

So there's some very easy solutions that doesn't cost anything for those that want to play it safe.

Laura Sanders: Thank you.

Coordinator: We have no other questions in queue at this time.

Dr. Nora Volkow: So if there are no other questions, I can add – I can bring up another question that I think is relevant in terms of trying to understand the significance. And which is – what is the magnitude of this effect in the brain? Is it very large? Is it very dramatic? Is it very small?

What do we know about the magnitude of the effects that you all observe? And what we saw overall in the area closest to the antenna was a 7% increase. And that 7% increase in glucose metabolism is actually within the range of physiological activation.

So as I'm speaking to you for example, my – the area of the brain that is involved in speech production, the Broca's area, is probably increasing metabolism by 10% to 15%.

And so is the area of the brain that's receptive, the Wernicke's area. So it's within the physiological range. Now when you do visual stimuli – which are very, very potent for us, the visual creatures – researchers have reported up to a 50% increase in metabolism in the visual cortex.

So we know that that is really a large effect. And when you compare that with the magnitude of what were observed, it's much smaller. But it's still within very much the range of physiological activation.

Coordinator: Okay, we do have another question in queue if you're ready. Okay, Laura Sanders from Science News again, your line is open.

Laura Sanders: Hi. I'm wondering if you can talk a little bit about other imaging experiments that have been done with cell phones? Are there some fMRI studies that have been done? And what do those show? And how is your study different?

Dr. Nora Volkow: Well there are several brain imaging studies that have been done that use Positron Emission Tomography that were reported at the beginning of the '90s and throughout the whole '90s.

They were using cerebral blood flow – actually there are three independent laboratories, measuring the effects of cell phone exposure on cerebral blood flow.

And our study differs from those prior studies. We took advantage of what we learned from their experiences in two ways. First of all those studies – all of them were conducted on a relatively small number of subjects which can, which is problematic when you're trying to detect a small signal. Because if you don't see a significant effect, you do not know if it is because its' not there or because you do not have the statistical power to detect it.

So the largest of those studies used 14 subjects. In our study we powered our study based on the findings that we had obtained to investigate the effects of magnetic fields employed in MRI studies of brain function. Which we had shown actually activated the brain – produced changes in metabolism.

So we used those findings in order to estimate the number of subjects that we require to see an effect of a similar or greater magnitude.

So that end – so that's why we ended up recruiting a total of 48 subjects. We had to drop one because the cell phone connection; we got disconnected while the study was going on.

So we ended up with 47 subjects, which is three times, at least three times larger than any of the other studies. Which of course increased the power to detect small effects.

Also, different from the other studies, we used glucose metabolism rather than cerebral blood flow. And glucose metabolism is a much more sensitive indicator of brain activity than blood flow per se. Because blood flow – increases in blood flow can occur even if there's no increase in neuronal activity.

Whereas that is not the case because when the cells are activated, by default you need to utilize glucose metabolism, so it's a more sensitive indicator. So those two were differences in terms of the methodologies and the design of our study with those done in the past.

There was a really superb study that actually was not done with imaging. But was very, very clever in 2006. And it was done in a small sample size. I think it was either 12 or 14 subjects.

But even with that small sample size, they showed that the brain, when it was exposed like us to 50 minutes of cell phone exposure, the area on the brain underneath that where the cell phone, the antenna was place was much more excitable.

And they measured that by recording the reactivity of the brain to magnetic pulses. So if you send the magnetic pulse to the motor cortex for example, you can get the contraction of the muscles.

And they recorded the intensity of the magnetic pulses that were required to produce a signal. And they showed a significant re–activity/excitability of the tissue after 50 minutes of cell phone exposure.

And so that was done without actually doing imaging. And is very consistent with our findings of increased utilization of glucose, which suggests an enhanced excitability of the neuronal tissue, which then becomes activated in an easier way. And therefore there is an increase in glucose metabolism.

Laura Sanders: Thank you.

Coordinator: And we have no other questions in the queue at this time.

Dr. Nora Volkow: If there are no more questions there's another point that I think it is important to ask us coming back to one of the questions that was – are there any recommendations that one can make, vis a vis this particular finding?

And I was commenting that I tend to be very conservative when it comes to my brain because I don't like anything to activate it that is not physiological.

But there is also another area where I'm very, very conservative. And that is when it comes to children and adolescence. And that is because the brain of children and adolescents is still developing. And there are many connections being formed.

And since we do not know for example the potential effects that this type of radiation may have on the formation or the deletion of these synaptic connections, it is an area where I would tend to be more conservative, vis a vis recommendations, for parents to try to encourage their children to avoid putting the cell phones close to their head.

Even though most kids use the cell phones by texting, there's some that still use them to communicate with one another. And there I would really encourage the use of an earpiece or the speakerphone to try to just be conservative.

Just because their brain is still developing and may be more vulnerable to effects than an adult brain would not be. And also because they are much more likely, since they are starting their lives with cell phones – whereas most of us started our lives without them – by the time they are middle aged, they would have had many more years of exposure to cell phones than we would ever have.

Coordinator: One moment, we do have a question coming in. We have a question from Renee Tessman from KAR TV, Minneapolis. Your line is open.

Renee Tessman: Thank you. Doctor this is more of a side note kind of question. But in looking at the JAMA story on this, it says of course that you're with the National Institute on Drug Abuse.

Again, tell me why are you doing a study on cell phones when you're expertise is more in the drug abuse field?

Dr. Nora Volkow: Yes I know. And that is correct. And so how did we end up, Brookhaven, studying the effects of cell phone? Well for many years we have been, you know, certainly I have devoted my professional life to study the effects of drugs in the human brain, all types of drugs.

And we used imaging technologies. And one of the imaging technologies that we use is Magnetic Resonance Imaging. So one of the questions that I wanted to address was whether the magnets used on the fields that we expose subjects in order to study their brain could directly affect the brain, how the brain functions.

So for the past 15 years we've done a series of studies to try to actually assess whether magnetic fields affect brain glucose metabolism – because actually, those imaging devices that you use to study the brain can it affect the brain itself?

And the first studies show that the static magnetic field of a 4–Tesla instrument did not at all affect the activity of the brain. But then we started to evaluate the effects of the gradients. Which actually – what they do is change very rapidly the magnetic field.

And because they are changing magnetic fields, they are producing electrical currents. And there – we reported this two years ago – we saw significant change in brain glucose metabolism.

So when we found out that this changing – rapid changing magnetic fields were able to produce changes in brain function, the question came around – well could it be, because we weren't expecting to see this, could it be that perhaps cell phones may also affect brain glucose metabolism?

So we came from the perspective of understanding the techniques that we used to study the effects of drugs on the brain, to coming around and realizing that the brain could be affected by magnetic waves.

And because of the extensive use of cell phones, then it – we said well we have this technique that we can just, let's try to address this, which is an important question.

That of course has generated a lot of interest in everyone in the community. And I mean it has generated an enormous amount of debate whether there is or there is not adverse consequences. And this is still unresolved.

Renee Tessman: Okay thank you Doctor.

Dr. Nora Volkow: You're very welcome.

Coordinator: Next we have Josh Smith from the National Journal. Your line is open.

Josh Smith: Hello, I apologize. I'm joining this call a little bit late. Could you explain again kind of what the – whether – what the conclusion is from this as far as so your study concludes that it's causing some of the glucose metabolism. But it's unclear still whether that constitutes a health risk. Is that correct?

Dr. Nora Volkow: Yes. What the conclusion is that the human brain is sensitive to the electromagnetic radiation that is delivered from cell phones.

And that in our study we saw that by observing that there was an increase in glucose utilization in the areas of the brain that are close to the antenna. Because increases in glucose utilization occur when cells are activated, we're interpreting this to reflect the fact that the electromagnetic radiation is increasing the excitability – the activation – of the areas of the brain where this radiation is being absorbed.

Now this is an acute effect. We observe it after 50 minutes of cell phone exposure. Increases in brain glucose metabolism by themselves are not harmful at all. In fact, they are physiological and normal events because that's the way that cells perform, get energy to perform their functions.

So by itself, observing an increase in glucose metabolism cannot be stated that it's deleterious. But what it does say is because it's showing that the cell – the brain is being activated.

What we need then need, the question that follows is – could repeated stimulation of these through these cell phone exposures say hours and a day after years, could they for example produce inflammatory responses that could be deleterious?

We don't know. Maybe yes, maybe no. We don't – we cannot, based on this study, determine that. And actually that is the next research question that we would like to address.

After having shown this we would like to be able to tackle that important question. Is there any evidence of long–lasting consequences from chronic exposure to cell phones in the brain?

Josh Smith: Thank you.

Coordinator: No other questions are in queue at this time.

Dr. Nora Volkow: Then I mean I'm going to also clarify another point because this is something that not everybody got in the description on the press release.

In our study we had two cell phones, one on the left and one on the right. And on one day the subjects were tested with the cell phones off. And on the other day, the subjects were tested with the right cell phone on and the left cell phone off.

Now why did we put two cell phones, one on the left and one on the right? We did it to try to control for the potential effects that expectation that the subjects may have of expecting a signal on one side of the brain versus the other.

And through our studies we have shown that your expectation about how you're going to, what the drug might make you feel, or how a stimulus will feel, can significantly affect the way that your brain responds.

So we wanted to be certain that there were no confounds from the expectation of the subjects expecting to receive a signal from the right cell phone. So they didn't know whether it was the left or the right.

Also, half of the subjects on the first day of the study, the phones were off. And for the other half, on the first day of the study, the right cell phone was on.

And we did this in order to control for order effects, which have been shown to happen when you're measuring brain glucose metabolism. So that is why we had the subjects blinded of whether – which cell phone was going to be transmitted.

And they were also blinded with respect to which day the cells will be completely off.

Coordinator: And again, it's star 1 if you would like to ask a question.

Dr. Nora Volkow: So if there are no questions the other thing that I think that is interesting, people have asked the questions – well, you know, weren't you expecting a larger effect? And I – over more than 7%, sort of like a 50%?

And the answer is no, not at all. If we – if you – if one would have expected such a large effect, like the 50% increases that one sees with visual cortical activation, we would have expected that then subjects/individuals using their cell phones would end up having seizures or listening – or activation – that they may have listened to sounds if they were being activating the auditory cortex. And obviously this does not happen, certainly not frequently.

But there are – there have been isolated cases in the literature that have been reported of individuals that when they use their cell phones have seizures. And this is likely to be individuals that are vulnerable to seizures and in whom the particular radio frequency, the frequencies of stimulation of the electromagnetic waves are activating areas of their brain that by themselves may already be – having increase excitability.

And then triggers the seizures in ways not dissimilar to what happens when some individuals that are prone to seizures can develop seizures just by looking at strobe lights of certain frequencies. And from these high frequencies can produce a seizure.

So there is evidence that some individuals have histories of seizures while they are using their cell phones, which could be compatible with the findings from the group in Italy that reported increased excitability after cell phone exposure.

Or our findings that are reporting increase glucose metabolism after cell phone exposure, particularly if the cell phone was used in areas where some of the seizure activity originate. Some of the areas that are on the brain that are more excitable.

Coordinator: Again it's star 1 to ask a question.

Dr. Nora Volkow: Another – so while there are no questions, the other question that I think is we need to consider as we make an interpretation of these findings is we use a cell phone that reflects the new technology.

In the past cell phones, most of the cell phones had their antenna on the upper part, which is of course closer to the brain. Now the new technologies tend to put the antenna on the lower parts of the brain.

In the past, the cell phones emitted much greater microwave radiation than current cell phones. And that was one of the areas that generated a lot of concern because the fear that this microwaves could produce increases in temperature that could be harmful to the cells in the brain.

And as a result of that there were very rigorous guidelines that were placed on the manufacturers of cell phones that limit the amount of microwaves that can be emitted and deposited in the brain.

And as a result of that, the belief is that the changes in the brain that we are observing, or that others may have observed are not due to increases in temperature produced by these electromagnetic radiation based on how the technology has evolved.

That is what it's believed currently. In the past perhaps that may be an issue. But the current technology it's unlikely to be the case.

We also need to be aware that the new cell phones that actually are – that – like the smart iPhones that are able to do many more things may be emitting more electromagnetic radiation.

And hence, if you place them close to your ear, may result in a greater exposure to this radiation. And that's something that needs of course to be addressed.

But as I say, the solution is very easy – you just use them on speakerphone. Or use a wire that connects to the cell phone too. If you are uncertain about the fact that you may be activating your brain, just use an earpiece.

So do we still have our reporters, do you know? Are there any reporters still on the line?

Coordinator: Yes and just now a question came in. Let's see this is Josh Smith from National Journal. Your line is open. One moment – go ahead Josh.

Josh Smith: Hi. I was just wondering – you're study mostly looks at, as you talk about the ways that people can avoid this radiation. As there's more and more devices out there that are emitting wireless radiation, this doesn't address at all a potential, or do you think there's potential for other wireless devices as more and more of these are out there? Even if they're not right next to your head, is that an issue?

Dr. Nora Volkow: Well, you know, based on the find – even though we didn't do a study to address those questions, what our study was able to show was that the effects were very localized only to the areas close to the antenna.

And areas that were 15 centimeters away, we could not observe any significant changes. And we have powered this study to be able to detect changes that were small and equivalent to those produced by a magnetic radiance.

So the fact that we are not observing any changes 15 centimeters away makes us think that it is unlikely that these other wireless technologies may have sufficient intensity to produce any changes based on these findings.

However, there's always the possibility that there are some changes that we cannot detect that we don't have the sensitivity. And that perhaps with cumulative exposure, one may see something.

But based on the current technology that we have, we could not see anything whatsoever, even if it's 15 centimeters away.

Josh Smith: Thank you.

Coordinator: No other questions are in queue.

Dr. Nora Volkow: And so while there are no questions, one of the other questions that people have been curious is – what about the other studies? What have they shown? Because there have been a lot of studies.

And some of the studies for example have evaluated whether cell phone exposure can affect cognitive performance. So you're doing a cognitive task with and without having the cell phone close to your head.

And some have shown that it does interfere, whereas others have shown that it doesn't interfere. Similarly, there have been studies looking at the electroencephalographic images that you detect for example using EEG, whether you're awake or asleep.

And some had reported that putting a cell phone close to your head while you're asleep affected the wave patterns coming out from the EEG, whereas others were not able to show such effects.

So the studies have – are difficult because of that – to interpret in terms of whether this could interfere with cognitive operations, if you are affecting an area of the brain for example that is involved with working memory or with memory itself.

Could it disrupt the way that you perform? Or could it improve it? We don't know, right? Because if it's activated could – is that something that could be utilized to enhance the function of that particular area?

And again, those are questions that would need to be researched. And hopefully the studies show that there are no adverse effects from these repeated stimulation because then we can really start to evaluate whether we could use these tools as means to activate areas of the brain either for research or for potential therapeutic applications. And then that would be an exciting area of research.

Coordinator: Again, star 1 to ask a question.

Dr. Nora Volkow: Finally, another clarification, while there are no questions – is that we use it for 50 minutes. So could a five minute, for example, stimulation – had we done only the study for five minutes, would it have produced the same effects?

And the answer is we really do not know. And that is, you know, actually an important question because there are many people that just use their cell phones for five or ten minutes.

And there are others of course that use it for longer periods of time. But I would say that most people will use the cell phone on any given call, perhaps just to – I'm going to be late 15 minutes, or I'm still in a meeting, wait for me – for very short periods of time.

And in that case, would the exposure be sufficient to create any type of activation? And that again is something that needs to be addressed. And our study does not in any way answer that question. Nor does the study – that very nice study done from the Italian group that show increased excitability –because that study also used a 50 minute exposure.

Coordinator: No questions in queue.

Dr. Nora Volkow: So do we still have reporters? Do you know?

Coordinator: Yes, there are still reporters on the line.

Dr. Nora Volkow: There's another aspect too that I think relates to one of the questions that was done earlier. Which was when you are speaking on the phone, you actually may be receiving greater amounts of electromagnetic radiation than when you're only listening to it.

But also there are differences in the amount of electromagnetic radiation that you are being exposed to, depending on the distance from which you are from the towers that are emitting the signals.

And also depending on how many individuals may be using their cell phones at any particular point and time.

And as a result of that, for example, it's very difficult to do clearly a retrospective study that is just based on the amount of cell phone exposures that you have. Because it's going to be affected really not just by the time you are on the cell phone, but also whether you are in a rural area where the tower may be far away.

Or whether you are in an urban area where you're close to a tower. And where a lot of people may be using the cell phones at the same time. And that's actually one of the reasons why it probably has been very difficult to make sense out of the epidemiological studies that have tried to establish an association between the retrospective recall of cell phone exposures and the prevalence rates of a cancer or other types of brain diseases.

And probably this variability on top of considering that some individuals use their cell phone on the left and some on the right, that they use different models so that the exposure may have been in different areas.

All of these complicates very much the interpretation of the epidemiological studies as they try to relate them to a greater or to a less prevalence rate of cancer from cell phone histories.

Coordinator: We still have no questions in queue.

Dr. Nora Volkow: So then I'll come up with another question. My brain has many questions because I do this study, and I end up with more questions then I started. So this is the way it is to be – to do research. You try to clarify something. And you end up full of questions.

And that has to do of course – why are there increases in metabolism? How would these very weak signals affect the brain? And one of the interpretations has to do with exactly that the particular radio frequencies of emission of these cell phones coincide with spontaneous oscillations at which neurons communicate with one another.

And so if there is a correspondence between that frequency and the oscillations, these two may amplify each other, creating a greater activation. So that the amplitude is enlarged.

And this is actually similar – this is explained by physicists with a very nice mechanical explanation of – if you are in a swing, and the swing is moving back and forth. If you start to push the swing at the same oscillation at which it was going, you'll create a greater and greater momentum so that the person in the swing moves further and further away.

So that is you increase the movement, the distance on the swing. So that's one of the interpretations. Others have postulated that perhaps this electromagnetic radiation could disrupt the blood brain barrier, and that in turn could produce changes in brain activity. Others have postulated that perhaps it could affect the function of enzymes in the brain that are involved in regulating cell activity.

Others have proposed that it may change electrical gradients across the membrane. And by doing that they may facilitate the release of neurotransmitters.

And since neurotransmitters is, either way that electrical signals are – communicate the message from one cell into the other. So there's an electrical signal goes from one side of the cell to the other.

And then when it ends, it releases a neurotransmitter. That neurotransmitter touches another neuron, creating an electrical current that is then transmitted.

So this is a way that – or some have hypothesized about – how these electromagnetic radiation could be affecting the brain and promoting the release of neurotransmitters that then lead to brain activation.

So all of these are – have been hypothesized. But as of now, they remain a hypothesis where nobody has really proven one or the other.

Coordinator: We have no questions in queue.

Dr. Nora Volkow: So – and we still have reporters?

Coordinator: Yes, there's a handful.

Dr. Nora Volkow: You know, one of the questions that people have asked me is that – has this affected my behavior? Have my findings affected my behavior?

And I thought this says, you know, and I said yes. And then said well are you – it is because you were worried? And I said no, no, no, no. It's not because I am worried about it per se.

But actually because the solution is so, so simple. I say if it doesn't cost you much, and you don't want to deal with uncertainty. And you just want to play it safe, I sort of says – well, why not.

And I guess that's the way that I – my own brain has reacted in terms of now I use the cell phone with a speakerphone or with an earpiece. And I try to avoid bringing the cell phone to my head.

If I have to, I will. But I just try to avoid it in between – until we are certain of whether it is – there is no negative effects. And maybe, who knows, maybe one day someone can find a potential application for activating the brain if there are no negative effects.

Coordinator: We have no questions in queue.

Dr. Nora Volkow: I sort of say – then let me make another question. I mean I was actually, you know, we had been in many ways surprised by the enormous interest that this story has generated. Because as I say, it does not clarify whether this has clinical significance, vis a vis, the deleterious effects or not.

But it is very interesting about how that reaction really reflects the concerns probably that people have of a new technology that was not there that really has exploded over the past 10 or 15 years.

And now is pervasive. And it's affecting our lives in many ways in overall very, very positive ways. But at the same time, it's a technology for which we have not had sufficient experience to really know whether there are any potential adverse effects in the way that we're using it or not.

So I think that that's exactly why the way that we're interpreting – why there has been such a great interest on this finding that the human brain is indeed sensitive to these electromagnetic radiation.

And in my brain, as a neuroscientist, is fascinating because it's actually – you know, we know that our brain is sensitive to light. We know that our brain is sensitive to sound.

But we really didn't know that our brain may be sensitive to very weak electromagnetic signals. And so what obviously are the implications of such a finding, vis a vis, why would our brain be – is this just a pure chance of nature?

Or are there perhaps evolutionary advantages to these? Or why is – I mean it's a very basic physiological question. What is the significance of this? I think it is to me, as a neuroscientist, a fascinating finding that I really – we really, my colleagues and I did not expect. We did not expect to find it.

Coordinator: We have no questions in queue.

Dr. Nora Volkow: Then I guess, do we have anyone from the other scientists that were involved at Brookhaven National Laboratories? So this is a project that really, it epitomizes the importance of teams of researchers with very, very different backgrounds that allowed this to happen.

So for example in our team we had two physicists, which allowed us to very much determine what were the parameters – how we needed to monitor the parameters for exposure to these electromagnetic radiation.

How to place the phones. How to measure where the antenna was placed with respect to the brain. How to optimally analyze the images. We had radiochemists involved in the study to try to actually also give input in terms of which would be the best biomarker to study the brain.

We had neurologists involved with the study to try to also understand what maybe the consequences from the clinical perspective of what we know of excitability.

We also have nuclear medicine physicians involved in terms of how do you optimally perform these studies to get the signals. We had the nurses, and very importantly the volunteers who actually were willing to come to the Brookhaven National Laboratory to be studied on two different days, having their cell phones there. And staying quietly.

It's really an effort, a remarkable effort from a very talented team of investigators at Brookhaven National Laboratory and the National Institutes of Health.

Coordinator: We have no questions in queue.

Dr. Nora Volkow: So if there's anyone, I think that if there's anyone from the Brookhaven National Laboratory team, I wonder if they would want to make a point, something that they think is important that may have not been asked. Or that I may have not mentioned.

Coordinator: Peter Genzer, I'll go ahead and open your line. Peter Genzer your line is open. He's disconnected.

Dr. Nora Volkow: Okay, okay. So anyone else, do we have any one of the reporters?

Coordinator: We have no questions in the queue.

Dr. Nora Volkow: I guess that, so if there are no questions I think that the last comment that I do want to make, and just to reiterate is that for us it sort of says – well, there has been this controversy about potential harmful effects of the brain.

How does this study help to address them? And I think that what it does is – while it does not specifically clarify whether there are or not deleterious effects, it clearly shows that the human brain is sensitive to them.

And by doing that, it does highlight the importance of doing the studies to evaluate whether there are long lasting consequences from repeated exposure to this type of cell phone technology to the human brain.

That we need to evaluate that so we can answer that question of whether there are or there are not untoward effects. And based on those findings, propose recommendations to minimize if there are harmful effects, any potential harmful effects of people that use this wonderful technology.

And if they are not, to encourage other investigators to see new ways of utilizing it and expanding its applications.

I think that that's probably on my part the last statement that I'd like to make. Since there are no more questions. And of course I want to thank the interest from the media on our study. And I want to thank you for helping us coordinate it.

Coordinator: Would you like me to close the call now Dr. Volkow?

Dr. Nora Volkow: Yes.

Coordinator: Okay, no problem. Today's call has ended. Please disconnect at this time.

Dr. Nora Volkow: Thanks very much.

Coordinator: You are welcome.

Dr. Nora Volkow: Bye bye.

This page was last updated February 2011

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