Mobile phones damage hearing - according to dodgy research

Another story claiming to show the dangers of mobile phone radiation has been doing the rounds of the predictable press – for example in the Mail,  the Telegraph, CTV, and Fox News.  As of 27 September Google provides over 800 hits for the story, some of them from sites offering specialist information for people with hearing impairments.

The story in the Mail is typical. It states that “the latest research” has shown that people who use their phones for longer than an hour per day found it hard to distinguish high frequency sounds – particularly “words starting with the letters s, f, h, t and z”. This wouldn’t be a very remarkable story if it hadn’t reported that:

“Researcher Dr Naresh Panda said it is possible radiation from longterm mobile use damages the inner ear.”

Such is his concern that he urged people to cut down on their phone use - “We should educate the public only to use them when necessary.”  For once the link to harmful effects from mobile phone radiation wasn’t just a bit of journalistic fluff. Dr Panda explicitly made that claim in the conference paper that was the source of the articles.

The paper in question is entitled Audiological disturbances in long term mobile phone users and it’s by Naresh Panda, Rishabh Jain, Jaimanti Bakshi and Sanjay Munjal. It was presented at a conference organised by the  American Academy of Otolaryngology Head and Neck Surgery (AAOHNS). They were so excited that the conference organisers wrote a press release entitled ‘Cell Phone Use Causes High Frequency Hearing Loss’ which is available here. 

Unfortunately, Panda et al don’t appear to have done very much research at all. The study only examined 100 people (fifty phone users, and a control of fifty people who had never used a mobile phone). Panda et al find some weak evidence for hearing loss, and inexplicably decide that the cause is radiation from mobile phones. Indeed, they do not speculate how phone radiation could damage hearing, whether such a link is plausible, or whether any other explanations are more likely. Instead they just presume that radiation is the only cause. The introduction states that:

“There is a general concern on the possible hazardous health effects of radiofrequency electromagnetic radiation (RFR) emitted from wireless communication devices, especially following the enormous increase in the use of wireless mobile technology throughout the world. The biological electrical activities that are vulnerable to interference from GSM radiation include highly organized electrical activities at a cellular level whose frequency happens to lie in the microwaves region, and which are a consequence of metabolism.”

Panda et al then hypothesise a special susceptibility of the ear: “Anatomically, the ear is in closest proximity to mobile telephones during use. So, theoretically its use should affect the ear most, although it is well covered inside a bony cage.” They return to this theme in the discussion section at the end of the paper: 

“The widespread use of mobile telephones has also given rise to concern about the potential influence of electromagnetic field on hearing of users, as ear is in closest proximity to mobile telephones during their use. […] Our study […] had patients who had symptoms of ear fullness, sensation of warmth around the ear and tinnitus while using mobile phones.”

To sum up, causality was presumed from the start of the paper. Panda et al did not discuss any alternative causes for the observed hearing loss. And they made no attempt to explain why they believe that electromagnetic radiation was the most likely cause. This is, to say the least, surprising for several reasons. First, scientists have consistently failed to find any evidence of electro-magnetic radiation from mobile phones harming the human body. For example, a Summary of research published by the World Health Organisation (available here) states that: “Scientists have reported other effects of using mobile phones including changes in brain activity, reaction times, and sleep patterns. These effects are small and have no apparent health significance.”

More importantly, there are other explanations for any observed hearing loss which are more likely then any revolutionary new radiation effect. For example, if they are loud enough, prolonged use of mobile pones may cause hearing loss, in the same way that any long term exposure to sound would. In addition, it has also been suggested that extensive mobile phone use could cause temporary fatigue in a person’s ability to discriminate between certain mid-range sounds. (See for example here, and the discussion  here). But such plausible alternative hypotheses weren’t considered in the paper. Occam’s Razor certainly needs to be sharpened in this case. 

But presupposing causality isn’t the worst problem with the paper - the authors admit in the abstract that:

“There was no significant difference for audiological abnormalities between users and controls.”

In fact, the only evidence for their conclusions was variations in hearing loss among the mobile phone users. There is no shame in reporting a null, or very weak result. Unfortunately, Panda et al don’t let the lack of any significant difference between the phone users and the control get in the way of a radical conclusion. They conclude that: 

“The possible explanation for presence of high frequency hearing loss amongst the control group is a matter of conjecture. It can probably be speculated that these control subjects may be residing in the vicinity of base stations or TV towers.”

This isn’t just another example of presupposing causality, it directly contradicts their earlier assertion that the ear should be most affected by mobile phone radiation (due to the proximity of the phone). Moreover, this is the second time that Panda et al ‘discover’ a completely new medical consequence of electromagnetic radiation that was previously unknown to science - from studying just 100 people.

So, there is a very small sample, no significant difference in the control group, and the authors make wild statements about causality. The only reason why Dr Panda is quoted across the world’s media as an expert scientist is that he made the eye-catching claim that mobile phones cause hearing loss.

One glaring question remains – why did the American Academy of Otolaryngology Head and Neck Surgery (AAOHNS) hype the story? We are used to journalists, either through incompetence or cynicism, writing fluff about the latest implausible discovery. But this story was hyped by an august professional association (which claims to represent over 12,000 otolaryngologists - “head and neck surgeons who diagnose and treat disorders of the ears, nose, throat, and related structures of the head and neck.”)

It’s bad enough encouraging journalists to write articles on preliminary and unpublished research presented in conference papers, but this paper is so flawed that writing a press release about it is positively negligent. I assume that they hyped this paper because anything on the dangers of mobile phones is bound to get press coverage. And press coverage, about anything, is more important than good research. Too bad that Panda et al will from now on be associated with a piece of nonsense.

 Edit: the original paper is available here.