Cochlear implants in children: safety as well as speech and language

Area of Science:

• Biomedical Engineering
• Auditory Neuroscience
• Speech Processing

Background:

• Cochlear implant development at the University of Melbourne and Bionic Ear Institute followed a rigorous safety-first approach.
• Initial research focused on atraumatic insertion, neural preservation, and infection prevention before pediatric trials.

Purpose of the Study:

• To evaluate the safety and efficacy of advanced cochlear implant speech processing strategies and electrode arrays in children.
• To assess the impact of visual dominance and cognitive factors on speech perception in pediatric cochlear implant users.

Main Methods:

• Sequential evaluation of speech processing strategies (e.g., second formant extraction, first formant integration, advanced combination encoder) in adults and then children.
• Pre-clinical safety testing in animals and human temporal bones for new electrode designs (e.g., Nucleus Contour array).
• Cognitive studies, including the McGurk effect, to investigate visual reliance and auditory stimulus clarity in deaf children with implants.

Main Results:

• Early strategies demonstrated significant open-set speech understanding in adults, leading to FDA approval in 1985 and 1990 for pediatric use.
• The Nucleus Contour array showed improved current localization and lower thresholds, with subsequent pediatric approval in 2000 for the ACE strategy.
• Cognitive studies revealed a strong reliance on visual information in implanted children, highlighting the need for clear auditory stimuli.

Conclusions:

• A systematic, safety-driven progression of cochlear implant technology has enabled effective auditory rehabilitation for children.
• Advanced speech processing and electrode designs, like ACE and the Contour array, are safe and effective for pediatric use.
• Understanding cognitive factors, such as visual dominance, is crucial for optimizing speech perception outcomes in pediatric cochlear implant recipients.