The bionic ear and brain plasticity
Brain plasticity is the ability of the brain to reorganise itself by forming new connections between brain cells (neurons) via new experiences.
Children as young as four months are now being implanted with a bionic ear. It has been observed that many children implanted with a bionic ear at a young age are able to comprehend speech and communicate almost as well as hearing children.
These diagrams show how the hearing part of the brain (auditory cortex) is organised from low frequencies (red) to high frequencies (blue) for people with normal hearing (TOP). By contrast the hearing part of the brain in deaf people can become disorganised if it is not stimulated early enough in life, due to lack of input (sound) (MIDDLE). Cochlear implant users from an early age have an auditory brain more like a hearing person.
We investigated how the use of the bionic ear (and the new “experience” of sound) contributed to brain plasticity – by promoting nerve cell survival and connectivity in the brain. Our goals were to study, using functional, anatomical and behavioural measures:
- the effects of the bionic ear on the developing auditory system for subjects implanted at a young age.
- the response of the auditory system in adults who have become deaf and have been implanted with a bionic ear.
- the effects of long-term bionic ear use on brain plasticity.
We achieved these goals by using a number of sub-disciplines of neurobiology, including electrophysiological, behavioural and neuroanatomical / molecular biological techniques.
This research was funded by the US National Institutes of Health (HHS-N-263-2007-00053-C)