EarGenie hearing test for babies
How does hearing impairment in babies affect speech development?
Babies learn to speak by hearing speech. So, not hearing the vital sounds needed in the early months of life means that speech development in babies who are deaf or hard of hearing can be delayed or permanently affected.
If the right management is not found in the first few months of life, these children never catch up with their peers, which affects their education, communication skills and future success in life.
The earlier that hearing issues are identified, and the baby provided with either a hearing aid or cochlear implant, the sooner they can start learning to speak, and the better language development will be.
What is the current situation with hearing tests for babies?
For many babies, the current newborn hearing tests can indicate how severe the hearing issue is, but it does not give key information about whether the brain can discriminate between sounds.
Information about discrimination between sounds is vital for audiologists to tune hearing aids or cochlear implants and optimise early intervention. However, it is often necessary to wait until a baby is 9 months old before audiologists can determine if their hearing devices is helping them to hear the sounds they need. This is because babies are too young to tell audiologists if their hearing devices are not tuned properly.
Around 10% of hearing-impaired children have a condition called auditory neuropathy and may have to wait until they are 2 years old before audiologists can select the right device because existing tests do not provide the necessary information. By this time, their language and communication skills are permanently affected.
Using light to assess hearing in babies
Researchers at the Bionics Institute are working on a new system called EarGenie, which will revolutionise hearing assessments for babies. EarGenie uses light (functional near-infrared spectroscopy or fNIRS) to measure the brain’s response to sounds.
A band wrapped around the baby’s head contains small light sources and light detectors. When the brain responds to a sound there is a change in oxygen level which can be recognised using specialised software.
These changes indicate whether the baby has heard the sound; and also, whether the baby can tell the difference between two different sounds, known as discrimination.
Eventually this technology will allow audiologists to tune hearing devices accurately from the very start, allowing babies to hear vital sounds and give them the best start in life.
Next steps for EarGenie
Researchers are currently testing EarGenie on babies with and without hearing impairment aged under two years old. As a result of these tests, new analysis techniques have been developed, which have lifted the accuracy of the device.
The EarGenie team has also developed new prototype equipment, making it more portable, moving from an awkward cap to a small headband and using a software system that makes it easier for audiologists to use.
Studies using this new prototype have demonstrated that its function is comparable to the fNIRS device initially used to establish feasibility of the technique in early clinical studies.
Want to get involved?
To continue with our research and development, we need to test EarGenie on infants younger than 24 months old, both with and without hearing impairment in our East Melbourne testing centre.
If your child is under 24 months of age, please consider participating in this vital study. We are looking for babies who are hard of hearing (any type) as well as those without hearing impairment.
Professor Colette McKay
Dr Mikhail Korneev, Dr Julia Wunderlich, Dr Darren Mao, Dr Gautam Balasubramanian and Mica Haneman.
Steven Lee and Ishara Paranawithana.
More information for researchers
Speech discrimination assessment is a key component of the audiometric test battery because of its functional relevance and importance for device choice (e.g., hearing aid versus cochlear implant). The average age of diagnosis has been greatly reduced by the introduction of universal newborn hearing screening, meaning that new clinical tests, applicable to very young infants, are required. However, there is currently no reliable and clinically feasible test (behavioral or objective) to measure speech discrimination in infants. The absence of such tests means that for individual infants, the optimal choice of hearing device and its accurate programming can be substantially delayed by many months.
Researchers in the Bionics Institute Babilab are using fNIRS, a neuroimaging technique that is portable, relatively cheap, and clinically viable in sleeping infants to address this gap. Apart from its suitability for use in infants, two other features of fNIRS make it an attractive modality in infants compared to auditory evoked potentials. Firstly, fNIRS allows testing without interference from electrical artifacts, a particularly useful feature when assessing cochlear implant users. Secondly, fNIRS can be used in infants with auditory neuropathy, as it does not rely on neural synchrony.
The research has involved creating novel stimulation protocols and an automated response detection algorithm that has resulted in a test for speech sound discrimination with >95% accuracy. The project is now in the commercial development phase for the EarGenie prototype with plans for clinical trials and regulatory approval underway.
Mao D, Wunderlich J, Savkovic B, Jeffreys E, Nicholls N, Lee OW, et al. Speech token detection and discrimination in individual infants using functional near-infrared spectroscopy. Scientific Reports. 2021;11(1):24006. https://doi.org/10.1038/s41598-021-03595-z