How many types of hearing aids are there? What's the difference?

Hearing aids and cochlear implants are both common means of helping hearing-impaired people regain their hearing, but most people don't know the difference between the two, so let's find out. The mechanism of action and the scope of application of different hearing aids is an acoustic amplifier, the original hearing-impaired patients can not hear the sound amplified to the intensity of the sound can be heard, as if to the ear set up a pair of "magnifying glass". It is inferred from the principle that the use of hearing aids requires the patient's residual hearing to be able to hear the amplified sound. However, the amplification power of hearing aids is limited. Therefore, hearing aids are mainly used by patients with moderate and partially severe deafness. If the residual hearing in both ears is severe or profound hearing loss, hearing aids are ineffective and cochlear implants are needed. A cochlear implant is an "artificial ear" that replaces the cochlea of a patient with severe hearing loss and can be compared to familiar implants such as artificial joints. The cochlear implant consists of an external processor that receives sound and transmits signals to the implant, which bypasses the damaged cochlear hair cells that sense sound and directly stimulates the auditory nerve, which then generates activity to re-establish hearing function. Therefore, cochlear implantation does not require the patient to have residual cochlear hair cells (i.e. residual hearing), but only complete auditory nerve function that can be utilized. Sound perception is different. Hearing aids simply amplify sound, so that hearing impaired patients can regain a familiar sense of hearing. In some cases, there are factors such as poor performance of the hearing aid, improper adjustment, etc. that may result in distortion (change in pitch) or unclear hearing. For cochlear implant patients, what they "hear" is actually an electrical stimulus, which is different from natural sound.