Browsing by Author "Kwon, Myoung Soo"
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- ItemEffects of mobile phone electromagnetic fields: critical evaluation of behavioral and neurophysiological studies.(2011-03-31) Kwon, Myoung Soo; Hämäläinen, HeikkiFor the last two decades a large number of studies have investigated the effects of mobile phone radiation on the human brain and cognition using behavioral or neurophysiological measurements This review evaluated previous findings with respect to study design and data analysis Provocation studies found no evidence of subjective symptoms attributed to mobile phone radiation suggesting psychological reasons for inducing such symptoms in hypersensitive people Behavioral studies previously reported improved cognitive performance under exposure but it was likely to have occurred by chance due to multiple comparisons Recent behavioral studies and replication studies with more conservative statistics found no significant effects compared with original studies Neurophysiological studies found no significant effects on cochlear and brainstem auditory processing but only inconsistent results on spontaneous and evoked brain electrical activity The inconsistent findings suggest possible false positives due to multiple comparisons and thus replication is needed Other approaches such as brain hemodynamic response measurements are promising but the findings are few and not yet conclusive Rigorous study design and data analysis considering multiple comparisons and effect size are required to reduce controversy in this important field of research
- ItemGSM mobile phone radiation suppresses brain glucose metabolism.(2011-12-01) Kwon, Myoung Soo; Vorobyev, Victor; Kännälä, Sami; Laine, Matti; Rinne, Juha O; Toivonen, Tommi; Johansson, Jarkko; Teräs, Mika; Lindholm, Harri; Alanko, Tommi; Hämäläinen, HeikkiWe investigated the effects of mobile phone radiation on cerebral glucose metabolism using high resolution positron emission tomography PET with the 18 F deoxyglucose FDG tracer A long half life 109 minutes of the 18 F isotope allowed a long natural exposure condition outside the PET scanner Thirteen young right handed male subjects were exposed to a pulse modulated 902 4 MHz Global System for Mobile Communications signal for 33 minutes while performing a simple visual vigilance task Temperature was also measured in the head region forehead eyes cheeks ear canals during exposure 18 F deoxyglucose PET images acquired after the exposure showed that relative cerebral metabolic rate of glucose was significantly reduced in the temporoparietal junction and anterior temporal lobe of the right hemisphere ipsilateral to the exposure Temperature rise was also observed on the exposed side of the head but the magnitude was very small The exposure did not affect task performance reaction time error rate Our results show that short term mobile phone exposure can locally suppress brain energy metabolism in humans
- ItemNo effects of mobile phone use on cortical auditory change-detection in children: an ERP study.(2010-03-15) Kwon, Myoung Soo; Huotilainen, Minna; Shestakova, Anna; Kujala, Teija; Näätänen, Risto; Hämäläinen, HeikkiWe investigated the effect of mobile phone use on the auditory sensory memory in children Auditory event related potentials ERPs P1 N2 mismatch negativity MMN and P3a were recorded from 17 children aged 11 12 years in the recently developed multi feature paradigm This paradigm allows one to determine the neural change detection profile consisting of several different types of acoustic changes During the recording an ordinary GSM Global System for Mobile Communications mobile phone emitting 902 MHz pulsed at 217 Hz electromagnetic field EMF was placed on the ear over the left or right temporal area SAR 1g 1 14 W kg SAR 10g 0 82 W kg peak value 1 21 W kg The EMF was either on or off in a single blind manner We found that a short exposure two 6 min blocks for each side to mobile phone EMF has no statistically significant effects on the neural change detection profile measured with the MMN Furthermore the multi feature paradigm was shown to be well suited for studies of perception accuracy and sensory memory in children However it should be noted that the present study only had sufficient statistical power to detect a large effect size
- ItemNo effects of short-term GSM mobile phone radiation on cerebral blood flow measured using positron emission tomography.(2012-03-05) Kwon, Myoung Soo; Vorobyev, Victor; Kännälä, Sami; Laine, Matti; Rinne, Juha O; Toivonen, Tommi; Johansson, Jarkko; Teräs, Mika; Joutsa, Juho; Tuominen, Lauri; Lindholm, Harri; Alanko, Tommi; Hämäläinen, HeikkiThe present study investigated the effects of 902 4 MHz global system for mobile communications GSM mobile phone radiation on cerebral blood flow using positron emission tomography PET with the 15 O water tracer Fifteen young healthy right handed male subjects were exposed to phone radiation from three different locations left ear right ear forehead and to sham exposure to test for possible exposure effects on brain regions close to the exposure source Whole brain O H O PET images were acquired 12 times 3 for each condition in a counterbalanced order Subjects were exposed for 5 min in each scan while performing a simple visual vigilance task Temperature was also measured in the head region forehead eyes cheeks ear canals during exposure The exposure induced a slight temperature rise in the ear canals but did not affect brain hemodynamics and task performance The results provided no evidence for acute effects of short term mobile phone radiation on cerebral blood flow
- ItemPerception of the electromagnetic field emitted by a mobile phone.(2008-01-14) Kwon, Myoung Soo; Koivisto, Mika; Laine, Matti; Hämäläinen, HeikkiElectromagnetic sensibility refers to the ability to perceive the electromagnetic field EMF without necessarily developing health symptoms attributed to EMF exposure A large sample of young healthy adults n 84 performed two forced choice tasks on the perception of the GSM mobile phone EMF 902 MHz pulsed at 217 Hz Was the field on and Did the field change 3 conditions x 100 trials for each task n 600 trials in total A monetary prize was announced for good performance correct response rate or 75 n 600 trials The performance was no better than expected by chance and thus none of the participants won the prize Two participants showed extraordinary performance in one of the task conditions Was the field on n 100 trials with correct response rates of 97 P 1 28 x 10 25 and 94 P 9 40 x 10 22 but they failed to replicate the result in the retest of six blocks of the same condition 1 month later Six participants had reported being able to perceive the mobile phone EMF in the preliminary inquiry but they performed no better than the others This study provides empirical evidence against the existence of electromagnetic sensibility to the mobile phone EMF demonstrating the necessity for replication in EMF studies
- ItemPreattentive auditory information processing under exposure to the 902 MHz GSM mobile phone electromagnetic field: a mismatch negativity (MMN) study.(2009-03-02) Kwon, Myoung Soo; Kujala, Teija; Huotilainen, Minna; Shestakova, Anna; Näätänen, Risto; Hämäläinen, HeikkiPrevious studies on the effects of the mobile phone electromagnetic field EMF on various event related potential ERP components have yielded inconsistent and even contradictory results and often failed in replication The mismatch negativity MMN is an auditory ERP component elicited by infrequent deviant stimuli differing in some physical features from the repetitive frequent standard stimuli in a sound sequence The MMN provides a sensitive measure for cortical auditory stimulus feature discrimination regardless of attention and other contaminating factors In this study MMN responses to duration intensity frequency and gap changes were recorded in healthy young adults n 17 using a multifeature paradigm including several types of auditory change in the same stimulus sequence while a GSM mobile phone was placed on either ear with the EMF 902 MHz pulsed at 217 Hz SAR 1g 1 14 W kg SAR 10g 0 82 W kg peak value 1 21 W kg measured with an SAM phantom on or off An MMN was elicited by all deviant types while its amplitude and latency showed no significant differences due to EMF exposure for any deviant types In the present study we found no conclusive evidence that acute exposure to GSM mobile phone EMF affects cortical auditory change detection processing reflected by the MMN