use the phone. As a result of concern about this possible association and the lack of robust data, through IARC (International Agency for Research on Cancer) the European Community has funded a study that is intending to recruit 2000 brain tumor subjects. This will examine the possible association of phone use with brain tumors, acoustic neuromas, and salivary gland tumors as well as examining the confounders that could be associated with phone use. One of the reasons for these concerns is a study in Poland conducted on military personnel with occupational exposure to RF. In this study Szmigielski27 suggested a sixfold elevation in the risk of lymphatic and blood cancers. However, the methodology of this study is considered to be unsatisfactory and the various methods used in the research are not adequately described. Other studies have also been reviewed28,29 involving groups of people exposed to RF radiation through their work or hobbies (e.g., radio amateurs). The most common reported diseases are lymphoma and leukemia and brain cancer. A number of cases of clustering of cancer incidence in the neighborhood of television and radio transmitter antennas have been reported. One example of these was studied by Dolk et al.30,31 and showed an increase of leukemia within 2 km of a television and radio transmitter in Sutton Coldfield, United Kingdom. However, when this study was extended to other medium wave and very high frequency (VHF) transmitting antennas, no similar clusters were found in other parts of the country.

26.3.6 Cognitive Effects

26.3.6.1 In Animals

Safety aspects of RF exposure can be grouped into three broad headings, namely, neurological, driving, and electromagnetic compatibility with safety critical devices, such as prosthetic implants, or with hospital-based devices. A survey carried out in Scandinavia by Mild et al.32 compared the effect of GSM and analog handset sources on the reported subjective symptoms in the users. The prevalent symptoms reported in this study were losses of concentration and memory loss but particularly fatigue, headache, warmth on the ear, burning of the skin, and tingling and tightness of the skin. The symptoms were more prevalent in analog than in GSM phones, which may be associated with the greater power consumption of analog phones and greater RF output. The study, however, does indicate that there may be increased levels of stress with the use of mobile phones, but why this should be greater for analog systems is a mystery. The possibility that RF exposure is associated with stress has been studied in animals. At thermal levels that involve elevation in body temperature of greater than 1° there are indications that this disturbs behavior and is probably associated with an avoidance reaction and attempts to get to areas of lower discomfort. An example is a study of the effects of 10 W·kg–1 at 600 MHz for 20 min in rats,33 which produced a dose-dependent deficit in object recognition. There seems no doubt that this is going to be a hyperthermic response to RF as a stressor. A study on spatial working memory function in rats34 showed that exposed animals at 0.6 W·kg–1 of 2.45 GHz made more errors than unexposed animals. This was stated to be related to changes the neurotransmitter activity of the brain, in particular, the intrinsic opioid levels that are associated with the “flight and fight” response and enable the organism to deal with stressful situations, and the alteration of cholinergic activities that are associated with memory and learning. The reported interference therefore could also be considered a stress response to the action of microwaves. A follow-up study by Sienkiewicz et al.35 in mice in a similar radial-arm maze task using pulsed 900-MHz radiation at 0.05 W·kg–1 showed that the exposed animals performed just as well as controls. However, there were other effects such as an increased fecal production during exposure. This again appears to be a possible stress effect. Philosophically, if 0.6 W·kg–1 could be considered nonthermal, then the last experiment at tenfold less is probably of little value in negating the existence of effects.

26.3.6.2 In Humans

Identification of effects in humans has been conducted by a number of researchers. Usually evoked responses are used as indicators of response. Three studies of evoked responses to GSM-like signals have been conducted. Urban et al.36 looked for visual sensory responses to checkerboard reversal and found that these were not affected. However, two other studies37,38 reported positive effects. The other types of

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