26/02/2009 - February 2009 - Science Update
The following is a quick summary of another five papers that have come out over the last couple of months related to effects of electromagnetic radiation.
This is the latest paper, presented at a conference of the IEEE, showing effects of the non-RF components of GSM tranmissions on components of sleep. That RF seems to affect sleep seems to be a relatively consistent finding[Huber 2002, Huber 2005, Hung 2007, Andrzejak 2008], and certainly suggests that it may be unwise for teenagers (and adults) to sleep with their phones under their pillows or on bedside tables.
The latest EHS provocation study to be published in the proceedings of the same IEEE conference as the above paper has found no effect on physiological symptoms caused by exposure to CDMA phone signals. The sample sizes were small, with only 18 self-declared EHS individuals and 19 controls, and the abstract is not clear on how many tests were performed, nor how long the wait time was between exposure and assessment of physiological systems. It is very hard to tell therefore whether it would have even been possible for the study to have found any effects due to potential issues with resolving power and accuracy of methodology design, and it does not appear that any attempt has been made to control for the nocebo effect (i.e. removing self-declared EHS individuals that show no preliminary signs of sensitivity).
Capone F et al
, (February 2009) Does exposure to extremely low frequency magnetic fields produce functional changes in human brain?
, J Neural Transm. 2009 Feb 3. [Epub ahead of print] [View Author's abstract conclusions
Researchers from Italy have found that pulsed ELF EMFs cause functional changes in the human brain: "After 45 min of PEMF exposure, intracortical facilitation produced by paired pulse brain stimulation was significantly enhanced with an increase of about 20%, while other parameters of cortical excitability remained unchanged. Sham field exposure produced no effects." Details of exposure are not available in the abstract, and we haven't yet seen the full paper, but this is a further demonstration of non-thermal effects of non-ionising electromagnetic radiation in live human subjects.
Luria R et al
, (November 2008) Cognitive effects of radiation emitted by cellular phones: The influence of exposure side and time
, Bioelectromagnetics. 2008 Nov 17;30(3):198-204. [Epub ahead of print] [View Author's abstract conclusions
A very recent paper from Israel has just been published analysing the effects of Radiofrequency radiation from GSM phones on spatial memory tasks in humans. Response times (RTs) and accuracy of the responses were recorded over 12 blocks of trials, and it was found that left-sided exposure generated a significantly longer reaction time when compared to right-sided and sham exposed groups. This indication that brain laterality may be very significant is an interesting and novel finding that may shed light on the difficulty in replicating cognitive performance studies. The authors summarise that: "These results confirmed the existence of an effect of exposure on RT, as well as the fact that exposure duration (together with the responding hand and the side of exposure) may play an important role in producing detectable RFR effects on performance. Differences in these parameters might be the reason for the failure of certain studies to detect or replicate RFR effects."
McNamee DA et al
, (February 2009) A literature review: the cardiovascular effects of exposure to extremely low frequency electromagnetic fields
, Int Arch Occup Environ Health. 2009 Feb 17. [Epub ahead of print] [View Author's abstract conclusions
A canadian literature review has been published assessing cardiovascular effects of exposure to extremely low frequency electromagnetic fields. The authors express that there have been a number of positive findings that have been difficult to replicate as "study design, small sample populations and confounding variables have hampered progress to date". They summarise that further important research is essential in the light of the ICNIRP guidelines not being adequate in themselves: "Identification of these problems, in the current context of international exposure guideline re-evaluation, is essential for future EMF studies. These studies should address the possible deleterious health effects of EMFs as well as the detection and characterization of subtle physiological changes they may induce. Recommendations for future work include investigating the macro- and microcirculatory relationship and the use of laboratory geomagnetic shielding."
Huber R et al
, (December 2002) Electromagnetic fields, such as those from mobile phones, alter regional cerebral blood flow and sleep and waking EEG
, J Sleep Res 2002 Dec;11(4):289-95 [View Author's abstract conclusions