Browsing by Author "Hamblin, D L"
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- 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
- 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