Off the top of my head..gosh, I have been involved with the Deaf community for over 10 years and have met several CI users so I would say about 70% did benefit (*note..benefit is based on the person's stastifaction with their CIs..could be anywhere from hearing some sounds to hearing speech) and about 30% didnt.
There is one guy I know who can hear the birds singing and other environmental sounds but cant hear when someone is calling his name. He got his CI in his 30s but I dont know his experience with auditory input. He tells people that he got no benefit from his CI so I am assuming that he had more expectations than being able to hear birds sing and etc. It is just speculation on my part based on what he said.
Got this article but for some reason, my computer cant download the whole thing...
Can Every Patient With Severe to Profound Sensorineural Hearing Loss Benefit from a Cochlear Implant?
Many people of all ages with many different kinds and patterns of hearing loss can qualify for cochlear implantation.
Unfortunately, not everyone can benefit from using a cochlear implant. Some forms of sensorineural hearing loss are a result of
destruction of or absence of the auditory nerve fibers. Therefore, there is nothing for the cochlear implant to stimulate. In other forms of hearing loss,
structural abnormalities of the inner ear prevent surgical implantation. In many forms of sensorineural deafness, the status of the auditory nerve fibers is unknown. In such cases, it can be difficult to predict the potential benefit of receiving a cochlear implant. Currently, researchers are studying the role of auditory nerve fiber survival to better predict performance before implantation. The duration of hearing loss and the age at which it occurred also seem to influence performance with an implant.
Cochlear Implant
Cochlear implants do not restore normal hearing, and benefits vary from one individual to another. Most users find that cochlear implants help them communicate better through improved lipreading, and over half are able to discriminate speech without the use of visual cues. There are many factors that contribute to the degree of benefit a user receives from a cochlear implant
http://www.entnet.org/HealthInforma...he bolded cases they would not be candidates.