 Given the huge number of cell phone users these days, even small, simple adverse health effects could have major implications. The major concern is that they're usually held close to the head, resulting in significant exposure to the brain. But what other tissues are on the side of the head where the phone is usually placed? Like how about your inner ear? I mean, that's the organ most frequently and directly exposed to cell phone radiation. So what about possible adverse effects on hearing? In fact, the ear canal may provide a natural route by which, you know, emissions can go deeper into our skull. OK, well, a first natural question to ask might be, do long-term cell phone users have worse hearing? Apparently so. 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 done was bilateral, detectable in both ears, which may be more consistent with a radiation effect than just a constant, loud noise in one ear effect. Now, this was comparing users to complete non-users. If you compare heavy to light users, there appears to be a dose response, meaning the longer the duration of daily cell phone use, up to four or five hours a day, the more the hearing loss. The higher the sound threshold before they could hear this hearing test tone, clearly revealing that researchers include the hazardous effects of mobile phone use on auditory function. Based on the study, they recommend that cell phones be used judiciously, as there does not seem to be any difference between non-users and those that just used it like 10 to 20 minutes a day. However, two hours a day did appear to be associated with a certain amount of hearing loss blamed on the exposure to the electromagnetic fields generated by the 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. To see if cell phone signals could affect the auditory nerve at all, period, they directly exposed the nerve to a cell phone hovering right over it in the middle of brain surgery for five minutes, and saw a dramatic deterioration of the nerve impulses, so much so they decided to stop the experiment early to avoid possible permanent damage. So obviously, this is a very unnatural situation, clearly far from reproducing EMF exposure, where you have things like skin, bone, blood, and brain in the way, but it does show the cell phone emissions are powerful enough to at least potentially affect nerve function. OK, but how about an interventional study on the effects of cell phones on hearing with your skull actually on? The first study ever published and 10 minutes of cell phone exposure had no effect. OK, so far so good. What about longer than 10 minutes? No effect at 15, 20, or 30 minutes, either. That's a relief. What about 60? 60 minutes did appear to have an immediate impact on hearing threshold levels at specific frequencies. Again, not to the extent someone would notice, but enough to be picked up on these hearing tests. What if you wear a Bluetooth headset? I mean, does Bluetooth radiation affect hearing? No effect on your pet rat. But what about the other members of your family? 30 volunteers were exposed to a Bluetooth headset device on standby for six hours, then full power for 10 minutes, and no changes in hearing detected. Maybe Bluetooth emissions just don't have the power to affect nerves? It's too bad that brain surgery group didn't try waving around some Bluetooth headsets, too. Oh, but they did. After showing that cell phone fields could deteriorate nerve impulses, they decided to repeat the experiment to see if the same thing happened with Bluetooth fields. Bluetooth operated higher frequencies, which at the same power might be more hazardous, but Bluetooth 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, the researchers conclude these findings indicate that using a Bluetooth headset may be safer in terms of effects on the nervous system, and therefore represents a viable solution for safer cell phone operation.