Browsing by Author "Croft, 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
- ItemThe sensitivity of human event-related potentials and reaction time to mobile phone emitted electromagnetic fields.(2006-04-12) Hamblin, D L; Croft, R J; Wood, A W; Stough, C; Spong, JThere is some evidence to suggest that exposure to mobile phones MPs can affect neural activity particularly in response to auditory stimuli The current investigation n 120 aimed to test recent findings in this area namely that N100 amplitude and latency would decrease and that P300 latency and reaction time RT would increase under active relative to sham exposure during an auditory task Visual measures were also explored A double blind counterbalanced crossover design was employed where subjects attended two sessions 1 week apart In both sessions participants 1 performed auditory and visual oddball tasks while electroencephalogram EEG was recorded with a MP set to sham exposure mounted over the temporal region and 2 performed the same tasks while the handset was set to active sham When active the MP transmitted for 30 min at 895 MHz average power 250 mW pulse modulated at 217 Hz average SAR 0 11 W kg Paired t tests compared difference scores from the sham sham session to those from the sham active condition The study was designed to detect differences of 1 4 of a standard deviation with a power of 0 80 There was no significant difference between exposure conditions for any auditory or visual event related potential ERP component or RT As previous positive findings were not replicated it was concluded that there is currently no evidence that acute MP exposure affects these indices of brain activity
- ItemThe use of a 'phantom scalp' to assess the possible direct pickup of mobile phone handset emissions by electroencephalogram electrode leads.(2003-08-01) Wood, A W; Hamblin, D L; Croft, R JA Phantom Scalp was constructed from a conducting foam mat to form a layer under a 62 electrode electroencephalogram cap closely approximating the electrical properties of a human scalp The mat was placed over a polystyrene manikin head to preserve a correct anatomical arrangement Electrical signals were recorded with a Global System for Mobile GSM communications mobile phone handset in place against the side of the head Amplitude spectra were compared for three phone conditions off standby and transmit At 217 Hz significant differences were obtained between transmit and the other two conditions but no significant differences were noted for the physiologically important range 0 5 30 Hz An anomalous difference was noted for one electrode in the range 30 45 Hz
- ItemUse of mobile phones and changes in cognitive function in adolescents.(2010-11-15) Thomas, S; Benke, G; Dimitriadis, C; Inyang, I; Sim, M R; Wolfe, R; Croft, R J; Abramson, M JSeveral studies have investigated the impact of mobile phone exposure on cognitive function in adults However children and adolescents are of special interest due to their developing nervous systems