Estimation of Exposure Time to GSM-900 Radiation ...

Estimation of Exposure Time to GSM-900 Radiation Causing Auditory Brainstem Response Changes in Rabbits Using NeuroFuzzy System T. N. Kapetanakis 1, A. Kaprana 2, I. O. Vardiambasis 1*, and M. P. Ioannidou 3 1

Broadband Communications and Electromagnetic Applications Laboratory, Department of Electronics Technological Educational Institute (TEI) of Crete, Chania Branch, GR-73133 Chania, Crete, Greece 2

ENT Department University Hospital of Crete, GR-71110 Heraklion, Crete, Greece 3

Department of Electronics Alexander Technological Educational Institute of Thessaloniki, GR-57400 Thessaloniki, Greece Abstract  The wide and growing usage of cellular phones has raised questions about the possible health risks associated with radio frequency (RF) electromagnetic fields. Since it is very difficult to accurately measure and quantify the RF exposure level for all individuals, it would be helpful for epidemiologists and cellular phone users to obtain a time estimate of specific radiation exposure generating health problems. In this paper, a neuro-fuzzy system (ANFIS) was developed to estimate GSM-900 radiation exposure time causing specific electrophysiological time-related changes in auditory pathway. The proposed system, exploiting available experimental results for auditory brainstem response changes in rabbits due to mobile phone radiation exposure, resulted in about 90% of correct time recognitions. Thus we have proved, on one hand the short-term effect of mobile phone usage to subjects’ auditory pathway, and on the other hand that it is possible to build an automated system detecting satisfactory the radiation exposure time. This system can be very useful, as it provides reliable exposure assessment, even though it is unsafe to extrapolate neurological data from nonhuman in vivo experiments.

INTRODUCTION International scientific research confirms that electromagnetic fields are biologically active in animals and humans, and in some cases can cause discomfort and disease [1]. Especially radiofrequency radiation from mobile phone use has been associated in many studies to an increased risk for brain tumors. Of all anatomical structures, the ear is closest to the mobile phone during usage and a number of studies have been carried out investigating the effect of mobile phone radiation on the auditory system. In a recent experimental animal study [2], the possible electrophysiological time-related changes in auditory pathway during mobile phone electromagnetic field exposure were investigated. Auditory brainstem response (ABR) is an electrical signal evoked from the brainstem and the central auditory pathway after sound stimulation of the ear. The procedure is to generate a brief click or tone pip from earphones and to measure the elicited neuronal action potentials by surface electrodes, typically placed at the vertex of the scalp and ear lobes. The amplitude (microvoltage) of the signal is averaged and charted versus time (msec), similarly to electroencephalography. ABR audiometry provide a unique method for noninvasive study of the pathophysiology of the human or other mammal hearing system. Since 1971 [3], the ABR recording method has been standardized and used

increasingly in otorhinolaryngology clinics to evaluate symptoms and problems related to the auditory pathway. The ABR signal is characterized by a series of vertex positive peaks labeled from I to VII. The latencies of the first five peaks, which represent brainstem transmission time and therefore brainstem auditory processing, are the most important parameters for evaluation and diagnosis by medical experts. The analysis of ABRs is usually conducted manually, following a four-step procedure: determination of the responses’ presence, detection of the main peaks, estimation of the different latencies between I, II, III, IV, and V peaks, and diagnosis of the possible problem [4]. As described in [2], twenty eight rabbits under general anesthesia were radiated via a power- and frequencyadjustable radio transmitter, which was designed and manufactured according to the needs of the experiment for GSM-900 mobile phone emission simulation. The transmitter was placed near the ear of each subject and the antenna was placed in the entrance of the external auditory bony canal, as shown in Fig. 1. ABRs were recorded during radiation (real time measurements) at regular time intervals, using the EP25-Eclipse platform (Interacoustics).

Figure 1: One of the subjects anesthesised with the needle electrodes, the inserted earphones and the radio transmitter in place [2; Fig. 1b]. [2]’s experimental study concluded that exposure to electromagnetic fields emitted by mobile phones affects the normal electrophysiological activity of the auditory system in rabbits. This effect became obvious from ABR recordings ipsilaterally to the exposed side, as those in

Fig. 2, since 30 min of exposure suffice to significantly prolong the interval latencies I–V and III–V.

work described here. The neuro-fuzzy system developed in this study can be very useful in providing epidemiologists and cellular phone users with satisfying exposure assessment, even though, due to the different structure and anatomy of animal brains, it is unsafe to extrapolate neurological and behavioral data from nonhuman in vivo experiments to the effect of mobile phone usage in humans. References [1]

Figure 2: ABR recordings after 60 min of radiation exposure at the right (upper curve) and left (lower curve) ears. In comparison with baseline recordings there is significant delay of the ABR waveform obtained from the right (ipsilateral) ear [2; Fig. 4].

[2]

EXPOSURE TIME ESTIMATION In this paper, we employ the ANFIS neuro-fuzzy structure, having as input the experimental results used in [2], in order to further investigate the statistically significant effect of the radiation exposure time to ABR parameters. The ANFIS (Adaptive Network-based Fuzzy Inference System), originally proposed in [5], has emerged as the combination of two powerful intelligent techniques: the artificial neural networks and the fuzzy logic approach, which have been adopted and tested to solve many realworld problems in recent years. This combination of fuzzy logic and neural networks into adaptive network architecture is the main fact making ANFIS so attractive in our investigation. Specifically, ANFIS integrates the greater learning capability of neural networks with a fuzzy logic appoach to construct a fuzzy inference system, with membership function parameters tuned using a back-propagation algorithm either alone or in combination with a least squares type of method. As the a priori knowledge is not excluded, a better starting point for training the ANFIS is generally provided, thus reducing the convergence time and improving the results. Since this type of neuro-fuzzy structure has proven to be a universal function approximator [5]-[6], we have decided to use it for this problem. Having as inputs the absolute latencies of waves I, II, III, IV, and V of both the baseline ABR recordings and the ABR recordings during specific radiation exposure time intervals, we train the ANFIS system to provide the time of exposure to GSM-900 radiation needed to cause certain ABR changes to healthy anesthetized rabbits (excluding though any other possible cause of changes in ABR). The ANFIS system has obtained the correct time recognition in 89% of the cases, which is a satisfactory result. Thus we have shown that it is possible to build an automated system based on neuro-fuzzy techniques, that detects radiation exposure time with decent reliability. This, along with the proven causality of mobile phone radiation exposure, are the most important results of the

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A.E. Kaprana, A.D. Karatzanis, E.P. Prokopakis, I.E. Panagiotaki, I.O. Vardiambasis, G. Adamidis, P. Christodoulou, and G.A. Velegrakis, "Studying the effects of mobile phone use on the auditory system and the central nervous system: A review of the literature and future directions", European Archives of OtoRhino-Laryngology, vol. 265, no. 9, pp. 1011 - 1019, Sep. 2008. A.E. Kaprana, T.S. Chimona, C.E. Papadakis, S.G. Velegrakis, I.O. Vardiambasis, G. Adamidis, and G.A. Velegrakis, “Auditory brainstem response changes during exposure to GSM-900 radiation. An experimental study”, Audiology & Neurotology, vol. 16, no. 4, pp. 270-276, 2011. D. Jewett and J. Williston, “Auditory-evoked far fields averaged from the scalp of humans”, Brain, vol. 94, pp. 681-696, 1971. J. Tian, M. Juhola, and T. Gronfors, “Latency estimation of auditory brainstem response by neural networks”, Artificial Intelligence in Medicine, vol. 10, pp. 115-128, 1997. J.-S.R. Jang, “ANFIS: adaptive-network-based fuzzy inference systems”, IEEE Transactions on Systems, Man and Cybernetics, vol. 23, no. 3, pp. 665-685, May 1993. J.-S.R. Jang and C.T. Sun, “Neuro-fuzzy modeling and control”, Proceedings of the IEEE, vol. 83, no. 3, pp. 378-406, Mar. 1995.

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Estimation of exposure time to GSM-900 radiation causing auditory brainstem response changes in rabbits using neuro-fuzzy system Kapetanakis, T. N. ; Kaprana, A. ; Vardiambasis, I. O. ; Ioannidou, M. P. ; Broadband Communications and Electromagnetic Applications Laboratory, Department of Electronics Technological Educational Institute (TEI) of Crete, Chania Branch, GR-73133 Chania, Crete, Greece

This paper appears in: Microwaves, Communications, Antennas and Electronics Systems (COMCAS), 2011 IEEE International Conference on Issue Date : 7-9 Nov. 2011 On page(s): 1 - 2 Print ISBN: 978-1-4577-1692-8 Digital Object Identifier : 10.1109/COMCAS.2011.6105947 Date of Current Version : 19 ∆εκέμβριος 2011

ABSTRACT The wide and growing usage of cellular phones has raised questions about the possible health risks associated with radio frequency (RF) electromagnetic fields. Since it is very difficult to accurately measure and quantify the RF exposure level for all individuals, it would be helpful for epidemiologists and cellular phone users to obtain a time estimate of specific radiation exposure generating health problems. In this paper, a neurofuzzy system (ANFIS) was developed to estimate GSM-900 radiation exposure time causing specific electrophysiological time-related changes in auditory pathway. The proposed system, exploiting available experimental results for auditory brainstem response changes in rabbits due to mobile phone radiation exposure, resulted in about 90% of correct time recognitions. Thus we have proved, on one hand the short-term effect of mobile phone usage to subjects' auditory pathway, and on the other hand that it is possible to build an automated system detecting satisfactory the radiation exposure time. This system can be very useful, as it provides reliable exposure assessment, even though it is unsafe to extrapolate neurological data from nonhuman in vivo experiments.

INDEX TERMS

• IEEE Terms Auditory system , Ear , Electromagnetic fields , Estimation , Humans , Mobile handsets , Rabbits

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