When babies are born, they undergo a hearing test with a simple little machine. What if one day that test could also predict how well a child will be able to read and identify those children early may need extra help? A new study has taken a crucial first step toward that possibility.
In PLOS Biology this week, Nina Kraus and colleagues at Northwestern University report the discovery of a biomarker for literacy in preschoolers. Looking at EEG recordings in 3-year-olds, they found that children’s ability to distinguish consonant sounds in a noisy environment predicts how well they will read, even in children who have not yet begun reading.
As Kraus explained to CNS:
Identifying a biological marker that can be used in prereaders has been the white whale of research in the neuroscience of reading as long as the field has existed, and to my knowledge this is the fastest and most powerful. The earliest interventions are the most effective, and the challenge we have now surmounted has been to identify who will benefit from these therapies.
Background noises common where children learn language, such blaring televisions and playing children, interfere with the brain’s ability to distinguish consonant sounds, which are more acoustically complex than vowels. In a press release, Kraus explained: “Everyday listening experiences bootstrap language development by cluing children in on which sounds are meaningful. If a child can’t make meaning of these sounds through the background noise, they won’t develop the linguistic resources needed when reading instruction begins.”
The study dovetails with work by Patricia Kuhl (University of Washington) and others about the importance of the auditory experience for children to acquire and understand language.
We are asking how the brain makes sense of speech in noise. Our view is that background noise disrupts the processes Pat [Kuhl] has documented, which is why children who are lagging their peers in language development struggle to pull a signal out of noise. Children need to learn to make sound-to-meaning connections in their everyday auditory experiences, and we believe these drive reading development and refine how well the nervous system transcribes sound.
Altogether, the research can facilitate interventions in young children that would help them improve sound-to-meaning mapping and which could ultimately lead to better reading skills.
While application of the 30-minute EEG test Kraus’ team used in preschoolers may be a ways off due to its complexity and cost, identifying this literacy biomarker opens the possibility for a testing procedure in the future.
For more on this study, please read the full press release and the paper in PLOS Biology, and check out the Northwestern Auditory Neuroscience Laboratory.
-Lisa M.P. Munoz