Researchers from the Economic and Social Research Institute (ESRI) have found "some evidence" that road traffic noise exposure has a negative impact executive function, a cognitive process that organises thoughts, decision-making and behaviour among a sample of older adults in Ireland.
Respondents whose residences had the highest levels of noise exposure achieved lower scores on the ‘animal naming test’ than other and the size of this correlation was said to be “considerable”.
The animal naming test involves respondents naming as many animals as they can in one minute. It tests executive function and requires efficient organisation of verbal retrieval and word recall.
The research, Road traffic noise and cognitive function among older adults, by Ciarán Mac Domhnaill, Owen Douglas, Seán Lyons, Enda Murphy and Anne Nolan was published on Thursday.
They estimated exposure to noise originating from road traffic during 2013 for residences in Dublin and Cork for 1,706 individuals aged 54 and over from the Irish Longitudinal Study on Ageing (TILDA).
Researchers said respondents with a primary education scored significantly lower on the test than those with a secondary education, and the gap related to education was only slightly larger than the one between respondents exposed to the most noise compared to the least.
“However, in a further analysis of a smaller sample for whom we also had data on air pollution, the relationship between noise and executive function became non-significant,” they said.
“This means that we cannot rule out the possibility that some other aspect of the urban environment such as exposure to higher levels of air pollution might have explained the relationship we saw in the data.”
The researchers added that the level of road traffic noise exposure depends upon many things that can be affected by public policy, including elements of urban planning and traffic management.
“When making such policy choices, it is useful for planners and transport policymakers to know more about how exposure to noise is related to different aspects of public health,” they said.
“This research focused on whether older adults whose residences were exposed to more road traffic noise scored differently on a range of cognitive tests than their counterparts in quieter areas.
“While there was no statistically significant relationship between road traffic noise and several types of cognition, results on a test of executive function were lower by a large and statistically significant amount.
“It will take further research to learn whether this type of cognition is more affected by road noise for older adults than other cognitive domains, or whether more complex processes are at play.”
