fNIRs test of phonological discrimination and inhibitory control

Project goals and methodology

Children who experience hearing loss from a young age are at risk for delayed language development and behavioural challenges, including difficulty in managing impulsive reactions, in addition to their auditory issues. Traditionally, diagnosing these problems has depended on observing children’s behaviour, which is not always feasible with very young children. As a result, by the time a reliable diagnosis is made, these children may already be significantly behind in their development. Our goal was to create a test suitable for young children that doesn’t require their active participation. As an initial step, we tested this method on adults. The insights gained from this project will inform us about its applicability to children and how we can tailor the test to better suit their needs.

Key findings

• – Our study, by monitoring adults’ brain responses, revealed neural markers that indicate how well a person can discriminate two words that sounded similar or how well they learnt new words.
• – As children with hearing loss may be wearing devices such as hearing aids and cochlear implants, the input from which are not as clear as the sound that we normally hear, we studied whether and how the distorted sounds may impact the neural markers that we identified in normal hearers. Our results found that, it is harder for adults to discriminate pairs of words that were distorted compared to the natural sounds. Even in these challenging listening conditions, the neural marker for discrimination was still measurable, suggesting that our paradigm may be suitable for testing listeners who wear hearing devices.
• – As it is often not feasible to acquire behavioral responses from young children to confirm their performance in a task, we compared the brain responses in adults when they performed the same tasks with and without responding to the task. Our results found that the absence of responses did not impact their neural marker for word learning, suggesting that the proposed paradigm may be suitable for testing word learning outcome in young children from whom behaviors are hard to quantify.

Conclusion  

This project identified biomarkers of higher-order processes that are essential for language development, which is useful for the prediction of language outcomes in individuals with hearing loss. This test could also complement EEG-based methods that we have developed to assess speech access. Better understanding of individual’s needs could lead to better personalized intervention for better outcome.