Northwestern researchers have found a biological marker they believe may play a role in the development of dyslexia, a learning disorder that affects reading accuracy and comprehension in about one in 10 people, according to a University news release published today.

Communication Prof. Nina Kraus and post-doctoral fellow Jane Hornickel co-authored the study, titled “Unstable Representation of Sound: A Biological Marker of Dyslexia,” which will appear in the Feb. 20 issue of The Journal of Neuroscience.

The researchers tested certain speech sounds while monitoring brain responses in 100 school children before finding a sound that strong readers identified consistently and poor readers struggled with, according to the release.

Children, however, can make up for their deficits in encoding sound through training. According to the release, Kraus found that reading and speech encoding, especially for consonants, improved in children fitted for listening devices through which their professor’s voice was directly transported to their ear.

“Use of the devices focused youngsters’ brains on the ‘meaningful’ sounds coming from their teacher, diminishing other, extraneous distractions,” Kraus said in the release. “After a year of use, the students had honed their auditory systems and no longer required the assistive devices to keep their reading and encoding advantage.”

Kraus is currently in the first year of a five-year longitudinal study called BioTots, which is examining the reading biomarkers in pre-school children, the release said. The project is sponsored by the National Institutes of Health. “Unstable Representation of Sound” in particular was sponsored by NIH in conjunction with Northwestern’s cognitive science program.

— Jillian Sandler