The Effects of Cell Phones and Bluetooth on Hearing

What impact might cell phone and Bluetooth radiation have on the inner ear?

“Given the huge number of mobile [cell] phone users at present days, even simple adverse health effects could have major implications.” “The major concern about cell phones is that they are usually held close to the head, resulting in significant exposure to the brain and other tissues on the side of the head where the phone is usually placed.” Other tissues? Yes, such as your inner ear, the organ most frequently and directly exposed to cell phone radiation. What about possible adverse effects on hearing? In fact, the ear canal “may provide a natural route by which emitted radiofrequency radiations may reach the peripheral and central nervous system,” going deeper into your skull.

A first natural question to ask might be: Do long-term cell phone users have worse hearing? Apparently, they do. Cell phone users were found to have detectable hearing loss, though not enough to be noticeable, suggesting long-term cell phone use might damage the inner ear. The damage was bilateral, or detectable in both ears, which may be more consistent with a radiation effect than simply a constant loud-noise-in-one-ear effect.

Now, this was comparing users to complete nonusers. As you can see at 1:20 in my video The Effect of Cell Phones and Bluetooth on Nerve Function, if you compare heavy cell phone users to light users, there appears to be a dose response: the longer the duration of daily cell phone use (up to four or five hours in this study), the more the hearing loss. Researchers found heavy-use participants had a higher sound threshold before they could hear the hearing test tone and concluded this “clearly revealed hazardous effects of mobile phone use on auditory function.” They went on to say that “based on the study, it is recommend to use mobile [cell] phones very judiciously,” as there does not appear to be any difference between non-users and those who just used it 10 to 20 minutes a day. Two hours a day, however, did appear to be associated with a certain amount of hearing loss, blamed on “long-term exposure to electromagnetic (EM) field generated by cellular phones.” But, to make a claim like that, you can’t just use observational studies like these. You need to put it to the test.

As you can see at 2:13 in my video, to determine if cell phone signals could affect the auditory nerve at all, for five minutes, researchers directly exposed the nerve to a cell phone hovering right over it—in the middle of brain surgery—and saw a dramatic deterioration of the nerve impulses. In fact, it was to such an extent that they decided to stop the experiment early “to avoid possible permanent damage to the auditory structures.” Obviously, this is a very unnatural situation that is “clearly far from reproducing the real-life EMF” exposure you would have with skin, bone, blood, brain, and the like in the way. It does, however, show that cell phone emissions are powerful enough to at least potentially affect nerve function.

How about an interventional study on the effects of cell phones on hearing that doesn’t involve brain surgery and where your skull is actually on? The first study on this ever published found that ten minutes of cell phone exposure had no effect. So far, so good. What about longer than ten minutes? Researchers found no effect at 15, 20, or even 30 minutes, but what about after an hour? “Sixty minutes of close exposure to electromagnetic fields emitted by a mobile phone” did appear to immediately impact hearing threshold levels at specific frequencies. Again, the effect was not to the extent you would notice a difference in your hearing, but it was enough to be picked up on these hearing tests.

What if you wear a Bluetooth headset? Does Bluetooth radiation affect hearing? Apparently, it has no effect…on your pet rat…but what about the other members of your family? “Thirty adult volunteers were exposed to a Bluetooth headset device (1) on ‘standby’ setting for 6 hours and (2) at full power for 10 minutes.” Researchers detected no changes in hearing. Could it be that Bluetooth emissions just don’t have the power to affect nerves? Too bad that brain-surgery research group didn’t try waving around some Bluetooth headsets, too.

Oh, but they did! After showing that cell phone electromagnetic fields could deteriorate nerve impulses, the researchers decided to repeat the experiment to see if the same happened with Bluetooth fields. Bluetooth operates at a higher frequency than cell phones, so, at the same power, Bluetooth might be more hazardous, but it also operates at nearly a thousand times lower strength. No surprise then that the Bluetooth device had no effect on the auditory nerve, even when it was completely exposed. “Taken together, these findings indicate that the alternative offered by a Bluetooth headset coupled with a cell phone kept in a pocket or on a table is generally safer in terms of EMF effects on the nervous system and therefore represents a viable solution for safer [cell phone] operation.”

This is part of my extended series on cell phone radiation. You may wonder why I’m interested in this topic since it doesn’t have anything to do with food. Well, like nutrition, it has multibillion-dollar industries vying to distort the science, so I wanted to help people sort fact from fiction. I produced a series on mammograms for the same reason. Check out:

KEY TAKEAWAYS

Since cell phones are typically held close to the head, the brain and other tissues, such as the inner ear, may be directly and significantly exposed to their radiation. As well, cell phone users have been found to have detectable hearing loss, though not enough to be noticeable except during a hearing test.
When comparing heavy to light cell phone use, there appears to be a dose response: the longer the duration of daily usage, the more the hearing loss. There doesn’t appear to be any difference between non-users and light-users (10 to 20 minutes daily), but using a cell phone for two hours a day seemed to be associated with hearing loss, blamed on “long-term exposure to electromagnetic (EM) field generated by cellular phones.”
When researchers directly exposed the auditory nerve to a cell phone in the middle of brain surgery, they saw such a dramaticdeterioration in nerve impulses they stopped the experiment early “to avoid possible permanent damage to the auditory structures.” This showed that cell phone emissions are powerful enough to at least potentially affect nerve function.
An interventional study that didn’t involve brain surgery found that “close exposure to electromagnetic fields emitted by a mobile phone” for an hour (but not less than that) appeared to immediately impact hearing threshold levels at specific frequencies. Again, the effect was not to the extent you’d notice, but it was enough to be picked up during a hearing test.
Bluetooth radiation, however, doesn’t appear to affect hearing. When 30 adult subjects were exposed to a Bluetooth headset on “standby” for six hours or at full power for ten minutes, researchers couldn’t detect any changes in hearing.
Bluetooth operates at a higher frequency than cell phones and, at the same power, may be more hazardous, but it functions at nearly a thousand times lower strength.
Researchers found that Bluetooth had no effect on the auditory nerve, even when it was completely exposed, and concluded that “a Bluetooth headset coupled with a cell phone kept in a pocket or on a table is generally safer in terms of EMF effects on the nervous system and therefore represents a viable solution for safer [cell phone] operation.”

For more on cell phones and Wi-Fi, see:

In health,

Michael Greger, M.D.

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