Do Mobile Phones Affect Brain Function?

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The World Health Organization concluded that cell phone radiation may cause brain tumors, but what about effects on cognitive function?

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Below is an approximation of this video’s audio content. To see any graphs, charts, graphics, images, and quotes to which Dr. Greger may be referring, watch the above video.

“At present, we don’t know precisely the degree to which the risk of cancer and other adverse health effects are increased by the exposure to [the radiofrequency] fields from cell phones…” I explored the brain tumor data previously. What other potential adverse health effects might there be? For example, what about effects on brain function?

“The dramatic increase in [the] use of cell…phones has generated concern about possible negative effects of [the] radiofrequency signals delivered to the brain. However, whether acute cell phone exposure affects the human brain is unclear.” So, researchers decided to put it to the test using PET scan technology, and did find elevated brain activity “in the region [of the brain] closest to the antenna” after 50 minutes of exposure to a cell phone call. But what does that actually mean? Well, it’s “evidence that the human brain [has at least some sensitivity] to the effects of [cell phone radiation].” The “increased metabolism in [brain] regions closest to the antenna suggests that brain absorption [of cell phone emissions] may enhance the excitability of brain tissue.”

“[T]he [potential] health consequences of this are unknown,” noted the accompanying editorial, though it suggests an effect on brain functioning is possible, potentially affecting “neurotransmitter and neurochemical brain activities.” Maybe that can explain the changes in psychological test outcomes observed after exposure to cell phone radiation. Wait, what?

Earlier studies failed to find an effect of short-term cell exposure on human cognitive performance, but this 2017 review noted that “[s]everal studies [now] indicate an increase in [things like brain tissue excitability,” which may translate out into measurable cognitive effects. This “cortical excitability [excitability of the outer layer of the brain] might…underpin disruption[s in] sleep” tied to cell phone exposure, for example, but may also improve reaction time.

If you expose people to active cell phones while playing a computer game, they can actually respond faster compared to sham exposure, meaning placebo exposure—same scenario, but with the cell phone turned off. So, the industry can be like okay, okay; so, cell phone radiation does affect brain function after all, but the effects are positive! A decrease in reaction time upon exposure to microwave radiation from cell phones can “help…people better respond to different threatening situations,…decreas[ing] errors [perhaps, maybe] reduc[ing destructive accidents.” But, the difference in reaction time was just a few thousandths of a second. Put all the studies together, “the effects seem so small that implications for human performance in everyday life can be practically ruled out.”

There was a study that found that heavy cell phone users did better on a test of the ability to filter out irrelevant information, but this improvement in focused attention may just be because heavy cell phone users have lots of practice carrying on conversations in crowded places. Overall, electromagnetic fields from cell phones “do not seem to induce cognitive or [fine motor skill] effects. Nonetheless, [one has to worry about] the existence of sponsorship and publication biases”—meaning maybe studies funded by cellphone companies were designed in a way to skew the results, or were quietly shelved and never published if they showed anything negative.

And, indeed, if you compare the source of funding and results of studies of the health effects of mobile cell phone use, “studies funded exclusively by industry were…substantially less likely to report…significant [health] effects.” It would look suspicious, though, if all the industry studies just showed no effects. So, some have accused the industry of taking obfuscation to a new level. “Although [yes,] the industry-funded studies were significantly more likely to [show no effects], as [one might] expect…, no two…studies reported the same effect[s], and the few attempts [at replication] failed. Thus, the apparent message of the studies…dovetail[s] well with the [industry’s] position that there are no reproducible biological effects.”

So, they’re not just denying the existence of effects. If the industry-funded studies all just universally found no effects, in contrast to independent research, the industry research program could have been more easily dismissed. Of course, they all couldn’t come out showing health effects—that would have been bad for business. So, by instead coming up with this wide hodge-podge of conflicting results, they can better protect themselves—perhaps all part of “a well-designed legal strategy” to fight off lawsuits. But, we may never know.

We do know that when the World Health Organization came out saying that cell phones may be causing brain tumors, the cellphone industry went into damage control to attack the agency—similar to when the WHO came out against secondhand tobacco smoke. “Sowing confusion and manufacturing doubt” is just what industries tend to do.

Please consider volunteering to help out on the site.

Image credit: Rahul Chakraborty via Unsplash. Image has been modified.

Motion graphics by Avocado Video.

Below is an approximation of this video’s audio content. To see any graphs, charts, graphics, images, and quotes to which Dr. Greger may be referring, watch the above video.

“At present, we don’t know precisely the degree to which the risk of cancer and other adverse health effects are increased by the exposure to [the radiofrequency] fields from cell phones…” I explored the brain tumor data previously. What other potential adverse health effects might there be? For example, what about effects on brain function?

“The dramatic increase in [the] use of cell…phones has generated concern about possible negative effects of [the] radiofrequency signals delivered to the brain. However, whether acute cell phone exposure affects the human brain is unclear.” So, researchers decided to put it to the test using PET scan technology, and did find elevated brain activity “in the region [of the brain] closest to the antenna” after 50 minutes of exposure to a cell phone call. But what does that actually mean? Well, it’s “evidence that the human brain [has at least some sensitivity] to the effects of [cell phone radiation].” The “increased metabolism in [brain] regions closest to the antenna suggests that brain absorption [of cell phone emissions] may enhance the excitability of brain tissue.”

“[T]he [potential] health consequences of this are unknown,” noted the accompanying editorial, though it suggests an effect on brain functioning is possible, potentially affecting “neurotransmitter and neurochemical brain activities.” Maybe that can explain the changes in psychological test outcomes observed after exposure to cell phone radiation. Wait, what?

Earlier studies failed to find an effect of short-term cell exposure on human cognitive performance, but this 2017 review noted that “[s]everal studies [now] indicate an increase in [things like brain tissue excitability,” which may translate out into measurable cognitive effects. This “cortical excitability [excitability of the outer layer of the brain] might…underpin disruption[s in] sleep” tied to cell phone exposure, for example, but may also improve reaction time.

If you expose people to active cell phones while playing a computer game, they can actually respond faster compared to sham exposure, meaning placebo exposure—same scenario, but with the cell phone turned off. So, the industry can be like okay, okay; so, cell phone radiation does affect brain function after all, but the effects are positive! A decrease in reaction time upon exposure to microwave radiation from cell phones can “help…people better respond to different threatening situations,…decreas[ing] errors [perhaps, maybe] reduc[ing destructive accidents.” But, the difference in reaction time was just a few thousandths of a second. Put all the studies together, “the effects seem so small that implications for human performance in everyday life can be practically ruled out.”

There was a study that found that heavy cell phone users did better on a test of the ability to filter out irrelevant information, but this improvement in focused attention may just be because heavy cell phone users have lots of practice carrying on conversations in crowded places. Overall, electromagnetic fields from cell phones “do not seem to induce cognitive or [fine motor skill] effects. Nonetheless, [one has to worry about] the existence of sponsorship and publication biases”—meaning maybe studies funded by cellphone companies were designed in a way to skew the results, or were quietly shelved and never published if they showed anything negative.

And, indeed, if you compare the source of funding and results of studies of the health effects of mobile cell phone use, “studies funded exclusively by industry were…substantially less likely to report…significant [health] effects.” It would look suspicious, though, if all the industry studies just showed no effects. So, some have accused the industry of taking obfuscation to a new level. “Although [yes,] the industry-funded studies were significantly more likely to [show no effects], as [one might] expect…, no two…studies reported the same effect[s], and the few attempts [at replication] failed. Thus, the apparent message of the studies…dovetail[s] well with the [industry’s] position that there are no reproducible biological effects.”

So, they’re not just denying the existence of effects. If the industry-funded studies all just universally found no effects, in contrast to independent research, the industry research program could have been more easily dismissed. Of course, they all couldn’t come out showing health effects—that would have been bad for business. So, by instead coming up with this wide hodge-podge of conflicting results, they can better protect themselves—perhaps all part of “a well-designed legal strategy” to fight off lawsuits. But, we may never know.

We do know that when the World Health Organization came out saying that cell phones may be causing brain tumors, the cellphone industry went into damage control to attack the agency—similar to when the WHO came out against secondhand tobacco smoke. “Sowing confusion and manufacturing doubt” is just what industries tend to do.

Please consider volunteering to help out on the site.

Image credit: Rahul Chakraborty via Unsplash. Image has been modified.

Motion graphics by Avocado Video.

Doctor's Note

This video is one in an extended series on the impacts of cell phones, including:

Speaking of conflicts of interests and political maneuvering, have you seen these videos I produced on cannabis? If not, check out Does Marijuana Cause Permanent Brain Damage in Teens? and Does Marijuana Cause Permanent Brain Damage in Adults?.

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