Browsing by Author "Revonsuo, Antti"
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- Item902 MHz mobile phone does not affect short term memory in humans.(2004-08-09) Haarala, Christian; Ek, Maria; Björnberg, Linda; Laine, Matti; Revonsuo, Antti; Koivisto, Mika; Hämäläinen, HeikkiWe studied the effects of an electromagnetic field EMF as emitted by a 902 MHz mobile phone on human short term memory This study was a replication with methodological improvements to our previous study The improvements included multi centre testing and a double blind design A total of 64 subjects 32 men in two independent laboratories performed a short term memory task n back which poses a varying memory load 0 3 items on the subjects memory They performed the task twice once each under EMF and sham exposure Reaction times RTs and accuracy of the responses were recorded The order of exposure and memory load conditions were counterbalanced across subjects and gender There were no statistically significant differences in performance between the two laboratories We could not replicate our previous results the EMF had no effect on RTs or on the accuracy of the subjects answers The inability to replicate previous findings could have been caused by lack of actual EMF effects or the magnitude of effects being at the sensitivity threshold of the test used
- ItemEffect of a 902 MHz electromagnetic field emitted by mobile phones on human cognitive function: A replication study.(2003-04-15) Haarala, Christian; Björnberg, Linda; Ek, Maria; Laine, Matti; Revonsuo, Antti; Koivisto, Mika; Hämäläinen, HeikkiOur study was a replication and extension with methodological improvements to a previous study on effects of the electromagnetic field EMF emitted by a 902 MHz mobile phone on human cognitive functioning Improvements on the previous study included multicentre testing and a double blind design A total of 64 subjects 32 men and 32 women in two independent laboratories performed a battery of 9 cognitive tasks twice while the EMF was on and while it was off Reaction times RTs and accuracy were recorded The order of exposure and tasks was counterbalanced across subjects and gender There were no statistically significant differences in performance between genders or laboratories Although the RTs and the accuracy of answers were very similar to those of our previous study our previous results were not replicated We concluded that EMF had no effect on RTs or on the accuracy of the subjects answers Further our results indicate that our EMF had no immediate effect on human cognitive functioning or that such effects are so small that they are observed on behavior only occasionally
- ItemEffects of electromagnetic field emitted by cellular phones on the EEG during an auditory memory task: a double blind replication study.(2003-12-29) Krause, Christina M; Haarala, Christian; Sillanmäki, Lauri; Koivisto, Mika; Alanko, Katarina; Revonsuo, Antti; Laine, Matti; Hämäläinen, HeikkiThe effects of electromagnetic fields EMF emitted by cellular phones on the event related desynchronization synchronization ERD ERS of the 4 6 6 8 8 10 and 10 12 Hz electroencephalogram EEG frequency bands were studied in 24 normal subjects performing an auditory memory task This study was a systematic replication of our previous work In the present double blind study all subjects performed the memory task both with and without exposure to a digital 902 MHz field in a counterbalanced order We were not able to replicate the findings from our earlier study All eight of the significant changes in our earlier study were not significant in the present double blind replication Also the effect of EMF on the number of incorrect answers in the memory task was inconsistent We previously reported no significant effect of EMF exposure on the number of incorrect answers in the memory task but a significant increase in errors was observed in the present study We conclude that EMF effects on the EEG and on the performance on memory tasks may be variable and not easily replicable for unknown reasons
- ItemElectromagnetic field emitted by 902 MHz mobile phones shows no effects on children's cognitive function.(2005-10-18) Haarala, Christian; Bergman, Monica; Laine, Matti; Revonsuo, Antti; Koivisto, Mika; Hämäläinen, HeikkiThe present study investigated the potential effects of a standard 902 MHz global system for mobile communication GSM mobile phone on 10 14 years old children s cognitive function A total of 32 children 16 boys 16 girls participated with their own and parental consent The subjects were 10 14 years old mean 12 1 years SD 1 1 They performed a battery of cognitive tests twice in a counter balanced order once while exposed to an active mobile phone and once during exposure to an inactive phone The tests were selected from those we used earlier with adults The statistical analyses showed no significant differences between the mobile phone off and on conditions in reaction times and accuracy over all tests or in any single test It was concluded that a standard mobile phone has no effect on children s cognitive function as measured by response speed and accuracy The present results challenge some earlier findings suggesting that the electromagnetic field EMF created by an active mobile phone would facilitate cognitive functioning
- ItemMobile phone effects on children's event-related oscillatory EEG during an auditory memory task.(2006-07-18) Krause, Christina M; Björnberg, Christian Haarala; Pesonen, Mirka; Hulten, Annika; Liesivuori, Tiia; Koivisto, Mika; Revonsuo, Antti; Laine, Matti; Hämäläinen, HeikkiTo assess the effects of electromagnetic fields EMF emitted by mobile phones MP on the 1 20 Hz event related brain oscillatory EEG electroencephalogram responses in children performing an auditory memory task encoding and recognition
- ItemPulsed and continuous wave mobile phone exposure over left versus right hemisphere: effects on human cognitive function.(2007-04-30) Haarala, Christian; Takio, Fiia; Rintee, Taija; Laine, Matti; Koivisto, Mika; Revonsuo, Antti; Hämäläinen, HeikkiThe possible effects of continuous wave CW and pulse modulated PM electromagnetic field EMF on human cognition was studied in 36 healthy male subjects They performed cognitive tasks while exposed to CW PM and sham EMF The subjects performed the same tasks twice during each session once with left sided and once with right sided exposure The EMF conditions were spread across three testing sessions each session separated by 1 week The exposed hemisphere EMF condition and test order were counterbalanced over all subjects We employed a double blind design both the subject and the experimenter were unaware of the EMF condition The EMF was created with a signal generator connected via amplifier to a dummy phone antenna creating a power output distribution similar to the original commercial mobile phone The EMF had either a continuous power output of 0 25 W CW or pulsed power output with a mean of 0 25 W An additional control group of 16 healthy male volunteers performed the same tasks without any exposure equipment to see if mere presence of the equipment could have affected the subjects performance No effects were found between the different EMF conditions separate hemisphere exposures or between the control and experimental group In conclusion the current results indicate that normal mobile phones have no discernible effect on human cognitive function as measured by behavioral tests