The frequent whine of airplane engines or the roar of road traffic could affect children’s reading comprehension and memory, new research shows.

The researchers aren’t talking about the occasional flyover or traffic jam. Instead, they focused on noise around busy Dutch, British, and Spanish airports. Every day, jets thunder into the skies and swoop down onto those runways. Meanwhile, cars, cabs, and buses whisk people to and from the airports.

University of London professor Stephen Stansfield, PhD, and colleagues studied the effects of all that noise on kids at nearby schools. The study appears in The Lancet.

“Our findings indicate that a chronic environmental stressor -- aircraft noise -- could impair cognitive development in children, specifically reading comprehension,” they write. “Schools exposed to high levels of aircraft noise are not healthy educational environments.”

Noisy Airplanes, Worse Reading?

The researchers got decibel readings on airplane and road traffic noise. They also gave reading and memory tests to more than 2,800 children aged 9-10. The kids also filled out questionnaires about their health, and their parents took the same questionnaires.

After collecting the data, the researchers showed that aircraft noise impaired reading comprehension and memory.

The reasons why aren’t clear. The researchers say they adjusted for social and economic factors.

It’s possible that teacher frustration, interrupted lessons, or “learned helplessness” on the part of the students could be involved, the study notes.

Read WebMD's "Noisy Places May Delay Kids' Speech"

Surprising Findings From Road Traffic

Road traffic noise was actually linked with better scores on a memory test. That was a surprise and deserves more attention, say Stansfield and colleagues.

Road traffic noise didn’t appear to affect reading. That contradicts findings from other studies, say the researchers. However, the highest levels of road noise they detected were lower than those from past research.

In addition, no links were seen between aircraft or road noise and self-reported health or mental health. Other studies have shown effects of aircraft noise on blood pressure, say the researchers.

“Aircraft noise, because of its intensity, the location of the source, and its variability and unpredictability, is likely to have a greater effect on children’s reading that road traffic noise, which might be of a more constant intensity,” they write.

Read WebMD's "Too Much 'Noise' May Lead to Dyslexia"

Hushing the Noise

A school’s location, insulation, and design could help buffer the effects of noise, say Stansfield and colleagues. However, that won’t override noise at home for kids living nearby.

An empty classroom should have less than 75 decibels of noise, and reverberations and echoes should be controlled, says Yale University medical school assistant professor Peter Rabinowitz, MD, MPH. That number comes from the American National Standards Institute, says Rabinowitz in an editorial in The Lancet.

“In the future, such efforts to identify and reduce sources of potentially harmful environmental noise might become a routine part of preventive medicine,” writes Rabinowitz, who works with Yale’s occupational and environmental medicine program.

Read WebMD's "Noise Is a Leading Cause of Hearing Loss"

By Miranda Hitti, reviewed by Brunilda Nazario, MD

SOURCES: Stansfield, S. The Lancet, June 4, 2005; vol 365: pp 1942-1949. Rabinowitz, P. The Lancet, June 4, 2005; vol 365: pp 1908-1909. News release, The Lancet.