RF IMPACT ON NEURONAL SYSTEM
The possible effects on the human health induced by ex- posure to EM fields have been investigated with practical experiments on humans and animals under different per- spectives: physiological alterations and cancer development [3] functional alteration in cognitive behaviour and memory [6], genetic mutations and genotoxicity [3], among the oth- ers. The wide literature in this field depicts a scenario where many discordant results have been obtained so far, still not allowing to confirm whether, and in which extent, RF radi- ations are deleterious for the human health. In this respect, the heterogeneous experimental setup for different RF labo- ratory tests has a significant impact in seeking statistically acceptable results.
2.1 RF Exposure and Alzheimer’s Disease
Alzheimer’s disease (AD) is a senile or presenile demen- tia and it is probably caused by the deposit of β-amyloid plaques disrupting the myelin layer of the axons, the fun- damental structure of the neuronal signal propagation in the neuronal system. However, the true causes are still not understood. The main symptoms of AD include impaired cognitive behaviour, loss of short term and long term mem- ory, disorientation, loss of language abilities, personality changes, deterioration of the immune system and eventual death. AD particularly reflects itself in terms of the small- world network characteristics of the brain, as described in Section 3. Compared to the healthy brain, the Alzheimer af- fected brain, shown by electroencephalogram (EEG) record- ings in [9], reveals reduced connections between different functional areas of the brain, smaller clustering coefficients and longer characteristic path-length. Existing therapies can prolong the average life expectation and are currently based on heavy pharmacological treatments. Medical re- search has been spending much efforts in finding final ther- apies. Recent experiment reported in [2] have shown that exposure to the EM field generated by CDMA mobile phones has potential benefits against the development of Alzheimer’s disease. Through experiments done on transgenic Alzheimer mice, improved cognitive behaviours were observed after long term exposure (8 months). The employed RF radia- tion was operating at 918 MHz, over a 2 hours per 24 hours cycle, with whole body specific absorption rate (SAR) of 0.25 W/kg ± 2 dB, which is equivalent to head transmission for standard cell phone use in humans. These preliminary results point to possible treatment of AD with the aid of RF exposure. To this end, it is fundamental to define the basis of a suitable model of the parameters governing EM expo- sure and effects they induce on the brain in a way similar to a communication network.