Living near cellphone towers that produce radio-frequency electromagnetic fields can amplify pain in amputees, suggests new research.
"Our study provides evidence, for the first time, that subjects exposed to cellphone towers at low, regular levels can actually perceive pain," said senior study author Mario Romero-Ortega, associate professor of bioengineering at University of Texas at Dallas, US.
Until this study, published online in the journal PLOS ONE, there was no scientific evidence to back up the anecdotal stories of people, who reported aberrant sensations and neuropathic pain around cellphone towers, the researchers said.
"Our study also points to a specific nerve pathway that may contribute to our main finding," Romero-Ortega noted. Most of the research into the possible effects of cellphone towers on humans has been conducted on individuals with no diagnosed, pre-existing conditions.
This is one of the first studies to look at the effects of electromagnetic fields (EMFs) in a nerve-injury model, Romero-Ortega said. The team hypothesised that the formation of neuromas -- inflamed peripheral nerve bundles that often form due to injury -- created an environment that may be sensitive to EMF-tissue interactions.
To test this, the team randomly assigned 20 rats into two groups -- one receiving a nerve injury that simulated amputation, and the other group receiving a sham treatment. Researchers then exposed the rats to a radiofrequency electromagnetic antenna for 10 minutes, once per week for eight weeks.
The antenna delivered a power density equal to that measured at 39 meters from a local cellphone tower. Researchers found that by the fourth week, 88 percent of rats in the nerve-injured group demonstrated a behavioural pain response, while only one rat in the other group exhibited pain at a single time point, and that was during the first week.
"Our model found that electromagnetic fields evoked pain that is perceived before neuroma formation; subjects felt pain almost immediately," Romero-Ortega said. The researchers believe that the protein TRPV4, which is known to be a factor in heat sensitivity, could be a mediator in the pain response for these rats.