Brain imaging used to diagnose hearing impairment in infants

Researchers at Monash University and the Bionics Institute have used cutting-edge light technology invisible to the human eye to non-invasively image brains, in order to help diagnose hearing impairments in infants and prescribe the most effective treatment as early as possible. Their results were published in the Journal of Neural Engineering.

Prolonged hearing loss can severely affect how the brain’s language areas develop, affecting a child’s ability to develop speech and language. Currently, several diagnostic tests are required to accurately determine the extent of hearing impairment in infants. Tests can extend for several months and are stressful for both the child and the parents.

The researchers used functional near-infrared spectroscopy to non-invasively image the brains of a group of normal hearing infants and measure how language areas of their brains develop and interconnect over time as they grow older. PhD student Ishara Paranawithana said the objective measurements of connectivity from normal hearing infants can be used as potential biomarkers to compare against those of infants with hearing impairment to determine their level of language development.

“Since the age of the infants in our study varied considerably, we could quantify how these regions become increasingly functionally linked together with age and compare with the connectivity levels seen in adults by the end of the first year,” he said.

“By establishing the typical developmental trajectory of language areas in early childhood, our results help us to better understand the altered connectivity and its effects on language delays often seen in hearing-impaired infants.

“Functional near-infrared spectroscopy (fNIRS) is a relatively inexpensive and child-friendly brain imaging technique suitable for clinical use. Having diagnostic tools that facilitate early assessment of hearing helps infants with impaired hearing access effective treatments earlier in life, giving them the best chance to keep up with their peers.”

Professor Colette McKay, lead researcher of infant hearing at the Bionics Institute, said the study is critical to understanding how language processing develops in infants. “The findings will help us track development of language in infants with hearing impairment, and optimise and fast-track their early intervention,” she said.

“Ultimately, we want to give babies born deaf or hard of hearing the best chance of hearing clearly and learning to talk.”

Image credit: iStock.com/Demkat