Patients with unilateral severe sensorineural deafness can integrate the acoustic and electrical signals from both ears after cochlear implantation to achieve the effect of binaural hearing. In addition, cochlear implantation can: 1. Improve speech recognition in noisy environments. 2. Improve the ability of sound source orientation. 3, patients with tinnitus in the affected ear before surgery can reduce tinnitus interference after surgery, with an effective rate of >95%. 4, The implanted side does not affect the speech listening ability of the normal ear on the opposite side. 5, unilateral cochlear implantation is better than bone-anchored hearing aids (BAHA, commonly known as bone-conduction hearing aids) in terms of sound source orientation, hearing under noise, and the natural feeling of hearing sound. Therefore, people with good hearing in one ear and severe sensorineural deafness in the other ear can be implanted with a cochlear implant in the deaf side.