AustraliŽ: Invloed van GSSm en UMTS op cognitieve functies.

maandag, 30 mei 2011 - Categorie: Onderzoeken

Bron: Journal of Clinical Neurophysiology (2011), doi:10.1016 2011.04.006

Leung S et al.

Effects of 2G and 3G mobile phones on performance and electrophysiology in adolescents, young adults and older adults.

Corresponding author at: School of Psychology, University of Wollongong, Northfields Ave., Wollongong, NSW 2522, Australia. Tel.: +61 2 4221 3652; fax: +61 2 4221 4163.

E-mail address: rcroft@uow.edu.au (R.J. Croft).

Highlights
???? This study examined the behavioural and electrophysiological changes associated with 2nd (2G) and 3rd (3G) generation mobile phone exposure in adolescents, young adults and older adults.
???? The present study employed tasks that were tailored to each individualís ability level.
???? The present study suggests that there are subtle effects from acute 2G and 3G exposure on human cognitive function.


Abstract
Objective:
This study examined sensory and cognitive processing in adolescents, young adults and older adults, when exposed to 2nd (2G) and 3rd (3G) generation mobile phone signals.

Methods:
Tests employed were the auditory 3-stimulus oddball and the N-back. Forty-one 13Ė15 year olds, forty-two 19Ė40 year olds and twenty 55Ė70 year olds were tested using a double-blind cross-over design, where each participant received Sham, 2G and 3G exposures, separated by at least 4 days.

Results:
3-Stimulus oddball task: Behavioural: accuracy and reaction time of responses to targets were not affected by exposure. Electrophysiological: augmented N1 was found in the 2G condition (independent of age group). N-back task: Behavioural: the combined groups performed less accurately during the 3G exposure (compared to Sham), with post hoc tests finding this effect separately in the adolescents only. Electrophysiological: delayed ERD/ERS responses of the alpha power were found in both 3G and 2G conditions (compared to Sham; independent of age group).


Conclusion:
Employing tasks tailored to each individualís ability level, this study provides support for an effect of acute 2G and 3G exposure on human cognitive function.

Significance:
The subtlety of mobile phone effect on cognition in our study suggests that it is important to account for individual differences in future mobile phone research.


2011 Published by Elsevier Ireland Ltd. on behalf of International Federation of Clinical Neurophysiology.


''The alpha ERD/ERS response is thought to represent event-related changes to thalamo-cortical networks of the brain, and as such the 3G and 2G effects might be loosely categorised as repre- senting an alteration to the dynamics of cortical activation (Pfurtscheller, 2001). The delayed ERD/ERS responses in both 3G and 2G conditions could also indicate that MP effects were related to a slowing down of synchronous activities in the working- and seman- tic memory system (Klimesch et al., 2004). It is not clear why the electrophysiological underpinnings (ERD/ERS) were altered in both the 2G and 3G conditions in the combined group whereas the cogni- tive/behavioural measurements were only affected by 3G, and par- ticularly so in the adolescent group. It may be speculated, however, that as the adolescent brain is still heavily undergoing maturational processes (Segalowitz and Davies, 2004; Brem et al., 2006), that the adolescents were less able to compensate for the electrophysiological alterations produced by the 2G and 3G expo- sures, and that given that behavioural measures are less able to iden- tify compensatory processes, behavioural impairment may have been obscured in the young adult and elderly groups.''


Discussion
That impaired performance found more strongly in the adolescents is also important as it means that individual differences need to be accounted for in mobile phone research. This is because age is only one variable that can differentiate participants in such research, and this raises the possibility that there are other variables that may result in heterogeneous outcomes that may cloud results and increase Type II error. Future research may thus benefit from considering other variables that may interact with potential mobile phone-related bioeffects



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