The sensitivity of human event-related potentials and reaction time to mobile phone emitted electromagnetic fields.
There 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.
Hamblin
D L
DL
Brain Sciences Institute, Swinburne University of Technology, Melbourne, Australia. dhamblin@swin.edu.au
Croft
R J
RJ
Wood
A W
AW
Stough
C
C
Spong
J
J
D000293:Adolescent; D000328:Adult; D000368:Aged; D040421:Cell Phone; D018592:Cross-Over Studies; D004311:Double-Blind Method; D004569:Electroencephalography; D004574:Electromagnetic Fields; D005071:Evoked Potentials; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged