Use of mobile and cordless phones and cognition in Australian primary school children: a prospective cohort study

Abstract

BackgroundUse of mobile (MP) and cordless phones (CP) is common among young children, but whether the resulting radiofrequency exposure affects development of cognitive skills is not known. Small changes have been found in older children. This study focused on children’s exposures to MP and CP and cognitive development. The hypothesis was that children who used these phones would display differences in cognitive function compared to those who did not.MethodsWe recruited 619 fourth-grade students (8-11 years) from 37 schools around Melbourne and Wollongong, Australia. Participants completed a short questionnaire, a computerised cognitive test battery, and the Stroop colour-word test. Parents completed exposure questionnaires on their child’s behalf. Analysis used multiple linear regression. The principal exposure-metrics were the total number of reported MP and CP calls weekly categorised into no use ('None'); use less than or equal to the median amount (‘Some’); and use more than the median (‘More’). The median number of calls/week was 2.5 for MP and 2.0 for CP.ResultsMP and CP use for calls was low; and only 5 of 78 comparisons of phone use with cognitive measures were statistically significant. The reaction time to the response-inhibition task was slower in those who used an MP ‘More’ compared to the ‘Some’ use group and non-users. For CP use, the response time to the Stroop interference task was slower in the ‘More’ group versus the ‘Some’ group, and accuracy was worse in visual recognition and episodic memory tasks and the identification task. In an additional exploratory analysis, there was some evidence of a gender effect on mean reaction times. The highest users for both phone types were girls.ConclusionsOverall, there was little evidence cognitive function was associated with CP and MP use in this age group. Although there was some evidence that effects of MP and CP use on cognition may differ by gender, this needs further exploration. CP results may be more reliable as parents estimated children’s phone use and the CPs were at home; results for CP use were broadly consistent with our earlier study of older children.Electronic supplementary materialThe online version of this article (doi:10.1186/s12940-016-0116-1) contains supplementary material, which is available to authorized users.

Outdoor and indoor sources of residential radiofrequency electromagnetic fields, personal cell phone and cordless phone use, and cognitive function in 5–6 years old children

“…Self-reported frequency of cell phone use in adolescents was associated with changes in some of the cognitive function test assessed one year later including working memory and learning, but not showing a clear direction of the association (Abramson et al, 2009;Thomas et al, 2010). A recent study carried out in children 8-11 years old found little evidence of a consistent association between cell phone or cordless phone use with specific cognitive functions including attentional function, working memory, and memory (Redmayne et al, 2016). Finally, another recent study investigating 10 year-old boys which performed spot measurements of electric fields in the 100 kHz to 6 GHz frequency range in the immediate surroundings of children's homes, a limited surrogate for individual exposure, showed associations between higher levels of RF-EMF exposure and impaired general cognitive and verbal development but not with specific cognitive functions such as attention, memory, visuomotor coordination, processing speed, or executive functions (Calvente et al, 2016).…”

“…Observational studies using self-reported data on cell phone use (Abramson et al, 2009;Redmayne et al, 2016;Thomas et al, 2010), cordless phone use (Redmayne et al, 2016), measured residential RF-EMF levels from mobile phone base stations (Hutter et al, 2006), or measured total spectrum RF-EMF levels in the immediate surrounds of the participant's house (Calvente et al, 2016) showed associations with certain cognitive function tests in adults and adolescents or children of 8-15 years old although results were inconsistent between studies. No previous observational studies have evaluated the association between several RF-EMF exposure sources and cognitive function in younger children.…”

Use of mobile and cordless phones and change in cognitive function: a prospective cohort analysis of Australian primary school children

“…In the cross-sectional analysis [10], the ‘more’ MP users had slower responses for the Go/NoGo task. However, the longitudinal analysis found that the ‘increase’ in MP calls group decreased their response time from baseline to follow-up more than the ‘no change’ group for this task.…”

“…Further details of testing administration are discussed elsewhere [10, 12]. The total number of errors for the spatial problem solving function, and response times (ms) and accuracy (%) for the rest of the CogHealth™ cognitive tests were assessed.…”

“…However, there are few community-based epidemiological studies involving children that assessed effects of MP and/or CP use on cognitive functioning [1, 10–12, 14]. The findings of these studies are inconclusive [1, 11, 12, 14].…”