Children with attention deficit hyperactivity disorder, or ADHD, are often prescribed powerful medications to help them stay focused in school. But adding white noise to a classroom may be just as effective as drugs at aiding learning among these pupils, suggest the surprising results of a Scandinavian study.
The research, led by Goran Soderlund of Stockholm University was carried out on 51 students at a secondary school in Norway.
The children were first assessed for their ability to pay attention in class. They were then given a test in which they had to remember as many items as possible from a list read out loud - either in the presence or absence of white noise. The results showed that children who normally have difficulty paying attention actually performed better when the white noise was turned on.
The researchers aren't sure why white noise - which is made up of random signals - seems to benefit the inattentive. But Dr. Soderlund noted that people with ADHD lack adequate levels of dopamine - a chemical messenger in the brain. He speculates they are easily distracted because the reduced availability of dopamine means the brain is operating at a suboptimal level of activity.
"You see people with ADHD often have difficulty sitting still. They are tapping their fingers or moving their feet," he said. "I think that activity translates into a kind of neural-noise in the brain - and it's their way of increasing their arousal and attention."
In a similar fashion, random white noise may boost neural activity so the brain works more efficiently, enabling the students to focus on their studies.Writing in the journal Behavioral and Brain Functions, the researchers predict their findings "could be of particular importance for the significant population of parents that are uneasy about the use of medication" for treating ADHD.
Still, there's a lot more work to do before researchers can recommend the use of white noise in schools - especially classes that include both attentive and inattentive pupils. That's because the random sound hinders the learning abilities of the students who normally pay attention. For them, it's just too much noise and they get distracted.
"Our study shows that different brains need different levels of external noise to work properly," he said.
The white noise used in the study was blasted at 78 decibels. "That's the level of your vacuum cleaner - it is a really, really harsh sound," Dr. Soderlund acknowledged.
He is now experimenting with different sound levels to find an optimal level for everyone. But if one can't be found, he suggests ADHD students could wear earphones that provide them with white noise - without distracting the other students.