Unfortunately (or rather fortunately), there are very strict guidelines on which hard-of-hearing patients are eligible for a cochlear implant. The rough rule of thumb is if a patient is NOT able to understand conversation over the phone while using a hearing aid, they might be a candidate.
Patients must keep in mind that cochlear implant does NOT restore normal hearing... it basically makes someone with bad hearing have improved, but not normal hearing. Furthermore, the sounds are quite mechanical and artificial lacking depth and simulations of what the cochlear implant hearing is like can be quite jarring. Listen to an audio simulation here.
Cochlear Implant Candidacy
In any case, the objective testing required to determine candidacy is shown below (taken from Cochlear.com):
Hearing Testing Falling within the Yellow Region |
Adults
- Individuals 18 years of age or older
- Moderate to profound sensorineural hearing loss in both ears
- Limited benefit from amplification defined by preoperative test scores of ≤ 50% sentence recognition in the ear to be implanted and ≤60% in the opposite ear or binaurally
- Severe to profound sensorineural hearing loss
- Limited benefit from binaural amplification
- Multisyllabic Lexical Neighborhood Test (MLNT) or Lexical Neighborhood Test (LNT) scores ≤ 30%
- Profound sensorineural hearing loss
- Limited benefit from binaural amplification
Hybrid Cochlear Implant Candidacy
There is a newer type of device called a hybrid cochlear implant that combines a hearing aid with a cochlear implant that benefits individuals who have normal low frequency hearing, but very bad high frequency hearing. Candidacy for this device shown below (taken from Cochlear.com):
Hearing Testing Falling Within the Purple Region |
- Typical preoperative hearing of candidates ranges from normal to moderate hearing loss in the low frequencies (thresholds better than 60 dB HL up to and including 500 Hz) and Severe to profound mid to high-frequency hearing loss (threshold average of 2000, 3000, and 4000 Hz ≥75 dB HL) in the ear to be implanted.
- The CNC word recognition score criteria are between 10% and 60%, inclusively, in the ear to be implanted in the preoperative aided condition.
- The contralateral ear’s CNC score criteria are equal to or better than that of the ear to be implanted, but not better than 80% correct.
- Moderately severe to profound mid- to high frequency hearing loss (threshold average of 2000, 3000, and 4000 Hz ≥ 60 dB HL) in the contralateral ear.
The first video below contains actual surgery footage. The second video is animation only.
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