Browsing by Author "McKenzie, R J"
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- ItemComparison of the effects of continuous and pulsed mobile phone like RF exposure on the human EEG.(2008-02-15) Perentos, N; Croft, R J; McKenzie, R J; Cvetkovic, D; Cosic, IIt is not clear yet whether Global System for Mobiles GSM mobile phone radiation has the ability to interfere with normal resting brain function There have been reports that GSM exposure increases alpha band power and does so only when the signal is modulated at low frequencies Huber R Treyer V Borbely A A Schuderer J Gottselig J M Landolt H P Werth E Berthold T Kuster N Buck A and Achermann P Electromagnetic fields such as those from mobile phones alter regional cerebral blood flow and sleep and waking EEG J Sleep Res 11 289 295 2002 However as that research employed exposure distributions that are not typical of normal GSM handset usage deep brain areas were overexposed it remains to be determined whether a similar result patterning would arise from a more representative exposure In this fully counterbalanced cross over design we recruited 12 participants and tried to replicate the modulation linked post exposure alpha band power increase described above but with an exposure source dipole antenna more closely resembling that of a real GSM handset Exposures lasted for 15 minutes No changes to alpha power were found for either modulated or unmodulated radiofrequency fields and thus we failed to replicate the above results Possible reasons for this failure to replicate are discussed with the main reason argued to be the lower and more representative exposure distribution employed in the present study In addition we investigated the possible GSM exposure related effects on the non linear features of the resting electroencephalogram using the Approximate Entropy ApEn method of analysis Again no effect was demonstrated for either modulated or unmodulated radiofrequency exposures
- ItemThe effect of mobile phone electromagnetic fields on the alpha rhythm of human electroencephalogram.(2007-12-24) Croft, R J; Hamblin, D L; Spong, J; Wood, A W; McKenzie, R J; Stough, CMobile phones MP emit low level electromagnetic fields that have been reported to affect neural function in humans however demonstrations of such effects have not been conclusive The purpose of the present study was to test one of the strongest findings in the literature that of increased alpha power in response to MP type radiation Healthy participants N 120 were tested using a double blind counterbalanced crossover design with each receiving a 30 min Active and a 30 min Sham Exposure 1 week apart while electroencephalogram EEG data were recorded Resting alpha power 8 12 Hz was then derived as a function of time for periods both during and following exposure Non parametric analyses were employed as data could not be normalized Previous reports of an overall alpha power enhancement during the MP exposure were confirmed relative to Sham with this effect larger at ipsilateral than contralateral sites over posterior regions No overall change to alpha power was observed following exposure cessation however there was less alpha power contralateral to the exposure source during this period relative to ipsilateral Employing a strong methodology the current findings support previous research that has reported an effect of MP exposure on EEG alpha power
- ItemEffects of 2G and 3G mobile phones on human alpha rhythms: Resting EEG in adolescents, young adults, and the elderly.(2010-08-09) Croft, R J; Leung, S; McKenzie, R J; Loughran, S P; Iskra, S; Hamblin, D L; Cooper, N RThe present study was conducted to determine whether adolescents and or the elderly are more sensitive to mobile phone MP related bioeffects than young adults and to determine this for both 2nd generation 2G GSM and 3rd generation 3G W CDMA exposures To test this resting alpha activity 8 12 Hz band of the electroencephalogram was assessed because numerous studies have now reported it to be enhanced by MP exposure Forty one 13 15 year olds forty two 19 40 year olds and twenty 55 70 year olds were tested using a double blind crossover design where each participant received Sham 2G and 3G exposures separated by at least 4 days Alpha activity during exposure relative to baseline was recorded and compared between conditions Consistent with previous research the young adults alpha was greater in the 2G compared to Sham condition however no effect was seen in the adolescent or the elderly groups and no effect of 3G exposures was found in any group The results provide further support for an effect of 2G exposures on resting alpha activity in young adults but fail to support a similar enhancement in adolescents or the elderly or in any age group as a function of 3G exposure
- ItemEffects of 2G and 3G mobile phones on performance and electrophysiology in adolescents, young adults and older adults.(2011-09-29) Leung, S; Croft, R J; McKenzie, R J; Iskra, S; Silber, B; Cooper, N R; O'Neill, B; Cropley, V; Diaz-Trujillo, A; Hamblin, D; Simpson, DThis study examined sensory and cognitive processing in adolescents young adults and older adults when exposed to 2nd 2G and 3rd 3G generation mobile phone signals
- ItemMobile phones and brain tumours: a review of epidemiological research.(2009-02-25) Croft, R J; McKenzie, R J; Inyang, I; Benke, G P; Anderson, V; Abramson, M JThere has been a great deal of public concern regarding the possibility that the use of mobile phone related technologies might result in adverse health effects Corresponding to this there has been substantial epidemiological research designed to determine whether the use of mobile phones MP has any effect on health and in particular whether it increases the risk of developing head and neck tumours Such literature is particularly heterogeneous which makes it difficult to pool in a meta analysis This paper thus reviews the epidemiological literature pertaining to the use of mobile phones and mobile phone related technologies and head and neck tumours in an attempt to consolidate the various reports Although there have been individual reports of associations between MP use and tumours this research is not consistent and on balance does not provide evidence of an association There are reports of small associations between MP use ipsilateral to the tumour for greater than 10 years for both acoustic neuroma and glioma but the present paper argues that these are especially prone to confounding by recall bias The reported associations are in need of replication with methods designed to minimise such bias before they can be treated as more than suggestive
- ItemSimulation of pulsed ELF magnetic fields generated by GSM mobile phone handsets for human electromagnetic bioeffects research.(2008-10-24) Perentos, N; Iskra, S; McKenzie, R J; Cosi, IHuman provocation studies that investigate the effects of Global System for Mobiles GSM communication systems on the brain have focused on Radio Frequency RF exposure We wish to further extend such study by investigating the effect of both RF and Extremely Low Frequency ELF field exposure the latter generated by the GSM handset s battery switching The use of a commercial handset as an exposure source for such investigations is problematic for a number of reasons and therefore a simulated exposure source capable of producing both RF and ELF components of exposure is desirable As a first step in developing such a source we have quantified and characterized the ELF field from several commercial handsets the RF characteristics being already well understood Through experimental measurement we deduce that these fields can be sufficiently simulated by a 9 mm radius loop residing 10 mm beneath the front surface of the handset device and carrying enough current to generate peak fields of 25 microT at the surface of the handset