Related Experiment Video
Updated: Feb 17, 2026
Cochlear Implant Surgery and Electrically-evoked Auditory Brainstem Response Recordings in C57BL/6 Mice
Published on: January 9, 2019
Cortical organization restored by cochlear implantation in young children with single sided deafness
Melissa Jane Polonenko1,2, Karen Ann Gordon3,4,5,6, Sharon Lynn Cushing3,5,6
1Institute of Medical Sciences, The University of Toronto, Toronto, ON, M5S 1A8, Canada. melissa.polonenko@mail.utoronto.ca.
Insights
Early cochlear implantation for single-sided deafness in young children rapidly restores bilateral auditory input. This intervention helps prevent developmental deficits and improves binaural hearing, crucial for social and educational development.
Area of Science:
- Pediatric audiology
- Neuroscience
- Cochlear implant technology
Background:
- Single-sided deafness (SSD) in children can lead to developmental issues.
- Early intervention is recommended to mitigate social and educational deficits.
- Neurodevelopmental preference for the better ear can occur without treatment.
Purpose of the Study:
- To investigate the effects of early cochlear implantation on cortical auditory processing in young children with SSD.
- To assess changes in brain activity following cochlear implant (CI) stimulation over time.
- To evaluate the potential for CI to restore bilateral auditory input and improve binaural hearing.
Main Methods:
- Studied five children (age ≤3.6 years) with SSD and normal hearing in the contralateral ear.
- Utilized multi-channel electroencephalography (EEG) to measure cortical evoked activity.
- Recorded EEG at acute, early chronic, and chronic CI stimulation phases.
Main Results:
- Consistent responses from the normal ear and significant changes in the implanted ear's activity were observed.
- Initial CI stimulation showed atypical lateralization and recruitment of extra-temporal areas in the left auditory cortex.
- These abnormalities resolved with chronic CI use, leading to the emergence of contralateral aural preference in both auditory cortices.
Conclusions:
- Early cochlear implantation in young children with SSD rapidly restores bilateral auditory input to the cortex.
- This restoration is essential for developing binaural hearing capabilities.
- Prompt intervention with cochlear implants can positively impact neurodevelopmental outcomes in children with SSD.
Abstract:
Early treatment of single sided deafness in children has been recommended to protect from neurodevelopmental preference for the better hearing ear and from social and educational deficits. A fairly homogeneous group of five young children (≤3.6 years of age) with normal right sided hearing who received a cochlear implant to treat deafness in their left ears were studied. Etiology of deafness was largely cytomegalovirus (n = 4); one child had an enlarged vestibular aqueduct. Multi-channel electroencephalography of cortical evoked activity was measured repeatedly over time at: 1) acute (0.5 ± 0.7 weeks); 2) early chronic (1.1 ± 0.2 months); and 3) chronic (5.8 ± 3.4 months) cochlear implant stimulation. Results indicated consistent responses from the normal right ear with marked changes in activity from the implanted left ear. Atypical distribution of peak amplitude activity from the implanted ear at acute stimulation marked abnormal lateralization of activity to the ipsilateral left auditory cortex and recruitment of extra-temporal areas including left frontal cortex. These abnormalities resolved with chronic implant use and contralateral aural preference emerged in both auditory cortices. These findings indicate that early implantation in young children with single sided deafness can rapidly restore bilateral auditory input to the cortex needed to improve binaural hearing.
Related Concept Videos
01:15Auditory Pathway
When viewed cross-sectionally, the cochlea reveals the scala vestibuli and scala tympani flanking...
01:13The Cochlea