Cognitive performance measures in bioelectromagnetic research--critical evaluation and recommendations.
BACKGROUND
The steady increase of mobile phone usage has led to a rising concern about possible adverse health effects of radio frequency electromagnetic field (RF EMF) exposure at intensities even below the existing safety limits. Accumulating evidence suggests that pulse-modulated RF EMF may alter brain physiology. Yet, whereas effects on the human electroencephalogram in waking and sleep have repeatedly been shown in recent years, results on cognitive performance are inconsistent.


METHODS
This review compares 41 provocation studies regarding the effects of RF EMF exposure similar to mobile telephones on cognitive performance measures in humans. The studies were identified via systematic searches of the databases Pub Med and ISI Web of Science and were published in peer-reviewed journals between 1998 and the end of 2009.


RESULTS
Based on a critical discussion within the scope of methodological standards it is concluded that state-of-the-art-methods in bio-electromagnetic research on RF EMF effects and cognition have neither been specified nor fully implemented over the last 10-11 years. The lack of a validated tool, which reliably assesses changes in cognitive performance caused by RF EMF exposure, may contribute to the current inconsistencies in outcomes. The high variety of findings may also be due to methodological issues such as differences in sample size and the composition of study groups, experimental design, exposure setup as well as the exposure conditions, and emphasizes the need for a standardized protocol in bioelectromagnetic research.


CONCLUSIONS
At present, no underlying biological mechanism has been identified which mediates the effects on brain functioning as observed in electroencephalographic (EEG) studies. A future aim must be to identify this mechanism as well as a reliable exposure protocol in order to gain more insights into possible behavioral and related health consequences of high-frequency EMF exposure.
University of Zurich, Institute of Pharmacology & Toxicology, Winterthurerstrasse 190, 8057 Zurich, Switzerland. sabine.regel@pharma.uzh.ch
Sabine J
SJ
Regel
Peter
P
Achermann
D040421:Cell Phone; D003071:Cognition / Q000502:physiology / Q000528:radiation effects*; D004574:Electromagnetic Fields / Q000009:adverse effects*; D004781:Environmental Exposure / Q000009:adverse effects / Q000032:analysis; D005260:Female; D006801:Humans; D008297:Male; D013647:Task Performance and Analysis
Neuroreport. 2000 Mar 20;11(4):761-4
10757515
Bioelectromagnetics. 2003 May;24(4):283-8
12696088
Eur J Appl Physiol. 2000 Jan;81(1-2):18-27
10552262
Bioelectromagnetics. 2005 Oct;26(7):571-7
16142782
Neuroreport. 2000 Feb 7;11(2):413-5
10674497
Bioelectromagnetics. 2006 Apr;27(3):215-20
16304701
J Sleep Res. 2007 Sep;16(3):253-8
17716273
Int J Radiat Biol. 1999 Apr;75(4):447-56
10331850
Bioelectromagnetics. 2008 Sep;29(6):488-97
18421712
Bioelectromagnetics. 2006 May;27(4):265-73
16437544
Occup Environ Med. 2010 Oct;67(10):708-16
20837651
J Sleep Res. 2002 Dec;11(4):289-95
12464096
Neurosci Lett. 2006 Apr 10-17;397(1-2):99-103
16406308
Int J Radiat Biol. 2002 Oct;78(10):937-44
12465659
Health Phys. 1998 Apr;74(4):494-522
9525427
Neuroreport. 2000 Oct 20;11(15):3321-5
11059895
Neuroreport. 2004 Nov 15;15(16):2557-60
15538195
Bioelectromagnetics. 2005;Suppl 7:S144-50
16059918
Neuroreport. 1998 Oct 5;9(14):3229-32
9831456
Bioelectromagnetics. 2007 Sep;28(6):415-32
17503518
Bioelectromagnetics. 2007 May;28(4):289-95
17203481
Neuroreport. 2002 Jan 21;13(1):119-21
11924872
Bioelectromagnetics. 2007 May;28(4):316-25
17216609
Bioelectromagnetics. 2009 Jan;30(1):59-65
18792947
Neuropsychologia. 2006;44(10):1843-8
16616941
Bioelectromagnetics. 2005 Feb;26(2):102-8
15672372
Bioelectromagnetics. 2008 Feb;29(2):145-53
17957702
Environ Health Perspect. 2006 Aug;114(8):1270-5
16882538
Occup Environ Med. 2008 May;65(5):342-6
17928386
Int J Radiat Biol. 2006 Jun;82(6):443-50
16846979
Clin Neurophysiol. 2002 Oct;113(10):1623-32
12350439
Clin Neurophysiol. 2006 Apr;117(4):900-5
16439184
Neuroreport. 2005 Nov 28;16(17):1973-6
16272890
Neuroreport. 2003 Jul 18;14(10):1361-4
12876474
Lancet. 2000 Nov 25;356(9244):1833-6
11117927
Neuroreport. 2004 Jan 19;15(1):161-4
15106850
Eur J Neurosci. 2005 Feb;21(4):1000-6
15787706
Bioelectromagnetics. 2004 Sep;25(6):452-6
15300731
Neurosci Lett. 1999 Nov 19;275(3):207-10
10580711
Bioelectromagnetics. 2005;Suppl 7:S138-43
15931678
Bioelectromagnetics. 2009 Apr;30(3):198-204
19194860
Australas Phys Eng Sci Med. 2003 Dec;26(4):162-7
14995060
Bioelectromagnetics. 2004 Oct;25(7):524-9
15376239
Neuroreport. 2003 Nov 14;14(16):2019-23
14600490
Bioelectromagnetics. 2006 Dec;27(8):613-27
16724317
Clin Neurophysiol. 2004 Jan;115(1):171-8
14706485
Neuroreport. 2004 May 19;15(7):1191-4
15129172
Neurosci Lett. 2007 Jun 21;421(1):82-6
17548154
Int J Radiat Biol. 2000 Dec;76(12):1659-67
11133048
J Toxicol Environ Health B Crit Rev. 2009 Oct;12(8):572-97
20183535
Neuroreport. 2000 Jun 5;11(8):1641-3
10852216
Clin Neurophysiol. 2006 Nov;117(11):2504-11
17005447
Bioelectromagnetics. 2008 Apr;29(3):237-41
18163437
Bioelectromagnetics. 2004 Jan;25(1):33-40
14696051
Bioelectromagnetics. 2001 Oct;22(7):519-28
11568938
Bioelectromagnetics. 2005 May;26(4):243-50
15832335
Bioelectromagnetics. 2007 May;28(4):296-308
17203478
Bioelectromagnetics. 1998;19(6):384-7
9738529
Neurosci Res. 2005 Nov;53(3):265-70
16102863
Bioelectromagnetics. 2006 Feb;27(2):119-26
16304688
Bioelectromagnetics. 2008 Jan;29(1):11-9
17694536
Neuroreport. 2007 May 28;18(8):803-7
17471070
Cent Eur J Public Health. 1999 Nov;7(4):165-7
10659374
J Cereb Blood Flow Metab. 2006 Jul;26(7):885-90
16495939
Bioelectromagnetics. 2003 May;24(4):262-76
12696086
Neuroreport. 2003 Feb 10;14(2):243-6
12598738