Effects of Binaural Hearing on Listening Effort and Cognitive Development in Mandarin-speaking Children With Cochlear Implants

The goal of this observational study is to learn how listening effort affects brain development and daily life in school-aged children (ages 6-18) who use cochlear implants (CIs), which are electronic devices surgically placed in the ear to help children with severe hearing loss hear sounds. The main questions it aims to answer are: Do children with CIs use more mental energy to listen than children with normal hearing, and does this extra effort slow their brain development over time? Does listening with two ears (bilateral CIs or a CI plus a hearing aid) reduce listening effort compared to listening with one ear only? How does listening effort affect children's ability to get along with others and adapt to daily life? Researchers will compare children with CIs to children with normal hearing to see if differences in listening effort lead to differences in cognitive development, social skills, and quality of life over 3 years. Participants will: Complete hearing tests to measure how well they understand speech in quiet and noisy settings Wear a functional near-infrared spectroscopy (fNIRS) headset and eye-tracking glasses during a short listening task (about 15-40 minutes) so researchers can measure brain activity and pupil size changes - these are safe, painless, and non-invasive ways to see how hard the brain is working to listen Take thinking and memory tests appropriate for their age Have a parent or guardian answer questions about their child's social skills and daily communication Return for the same set of tests at 1 year and 3 years after the first visit This study does not involve any new treatment or change to a child's current care. All children will continue their regular medical and rehabilitation plans. The study aims to enroll 360 children (120 with normal hearing and 240 with cochlear implants) at Guangdong Provincial People's Hospital in China. Results may help doctors better understand when children with CIs need extra support and how to impr