A new study (PDF) in Environmental Health Perspectives addresses claims that some individuals are sensitive to radio-frequency radiation (rf-emf), in this case to the area of the spectrum used by cell phones. Reading it gave me a strange sense of déjà vu, as the methodology of the study closely followed the approach used to explore similar claims in regards to WiFi radiation. In both studies, individuals who claimed to be sensitive were unable to accurately identify when they were being exposed to radiation.

The study was conducted in Britain, where its authors noted that up to four percent of the population claims to be subject to what is known as "electromagnetic hypersensitivity" (the World Health Organization has recently given it the catchy name "idiopathic environmental intolerance with attribution to electromagnetic fields," or IEI-EMF). But the authors point out that experimental evidence for this disorder is completely lacking:

A systematic review of 31 blind and double-blind provocation studies yielded no evidence that IEI-EMF individuals could detect the presence of rf-emf, and only seven studies indicated that exposure to rf-emf did affect health indices (Rubin et al. 2005). In two of these, however, the authors failed to replicate their own findings. Another four studies involved inappropriate use of statistics, while one reported improved mood in the active exposure condition.

Despite the absence of any evidence that IEI-EMF exists, the authors explored whether cell phone radiation might trigger physiological responses. 56 individuals who claimed to be rf-emf sensitive, along with 120 controls, were recruited; 12 test subjects and 6 controls dropped out during the study. The subjects were asked to rate their status in terms of a number of measures ("anxious", "tense", "agitated", "relaxed", "discomfort", and "tired") while pulse, heart rate, and skin conductance were measured.

During an initial session, test subjects were informed of sequential exposures to cellular transmission equipment for both the GSM and UMTS protocols. After that, all exposures in that and three further sessions were performed in a double-blind manner. During these sessions, individuals were asked to determine whether they felt they were being exposed at any particular moment.

The results were pretty clear. As the authors put it, "sensitive participants reported more symptoms than controls, but this was not related to exposure." GSM use did not correlate with symptoms, and an apparent difference in response to UMTS went away once the fact that it was over-represented in the first double-blind test was accounted for. Heart and blood flow measures were normal, and all sensitive individuals had high levels of skin conductance during all double-blind trials, regardless of exposure. Individuals claiming to be sensitive were unable to detect exposure at rates that were significantly different from random.

So, with both WiFi and cell phone sensitivity apparently eliminated, will this finally lay the issue to rest? Don't count on it. The BBC is reporting that an activist group is already focusing on the individuals that withdrew following the first session, claiming that these represented the most sensitive individuals, and that the exposure during the test made them too ill to continue. The continuing controversy suggests that further studies that also give me a sense of déjà vu may be needed.