Hearing aids can improve the communicative abilities of most individuals with hearing loss.
Amplification of sound is added in individuals with more severe hearing loss to improve the individual’s word discrimination and speech understanding abilities.
Impact of hearing loss
- Impairs communication at home, work or in social settings
- Reduces the quality of life
- Leads to depression, social isolation and anxiety
When hearing deficits progress beyond the ability of hearing aids to produce meaningful benefit, a cochlear implant (CI) provides an alternative hearing rehabilitative modality by stimulating the auditory nerve and nervous system directly.
A cochlear implantation typically entails a two-hour outpatient surgery and activation of the cochlear implant occurs four weeks after the surgery. During surgery, the receiver-stimulator device and electrode array is inserted into the basal turn of the cochlea.
After implant activation, sound is detected by the external processor, transmitted wirelessly to the implanted receiver-stimulator device and then converted to synchronised electrical impulses which are delivered through the electrode array to the spiral ganglion (hearing) nerve. Sound is therefore transmitted to the hearing nerve bypassing the impaired cochlea. Patients receiving cochlear implants typically require 6–12 months of experience and practice with the cochlear implant before optimal hearing and speech understanding results are achieved.
Candidacy for cochlear implant
- Moderate to profound sensorineural hearing loss in both ears
- Should have a functioning auditory nerve
- No physical contraindications for placement of implant
- Medical clearance for surgery
- Should have tried hearing aids and got almost no improvement in hearing
- Anyone who can hear well with hearing aids is not a good candidate for cochlear implants.
Evaluation for eligibility for cochlear implant
- Medical evaluation
- Hearing test
- Hearing aid evaluation
- Tests of speech understanding with appropriate hearing aids
- General communication assessment
- Balance assessment
- MRI or CT scan
- Psychology consultation