This study aims to assess hearing and speech perception, as well as quality of life, in deaf patients of all ages before and after cochlear implantation, and to explore differences across age groups and treatment subtypes, thereby providing evidence for personalized hearing and speech rehabilitation.

The study aims to conduct a comprehensive evaluation of auditory and speech perception abilities, as well as overall quality of life, in patients with hearing loss across all age groups undergoing cochlear implantation. By comparing pre- and post-operative outcomes, the study will investigate how different age cohorts and subtype groups respond to cochlear implantation treatment. The findings are expected to provide critical evidence to guide the development of individualized auditory and speech rehabilitation strategies.

Inclusion Criteria:

• Patients with severe or greater hearing loss (≥65 dB) scheduled to receive cochlear implant (CI) treatment.
• No restrictions on age or gender.
• Native language is Mandarin Chinese.
• The subject and/or their legal guardian must provide informed consent prior to the study, voluntarily sign a written informed consent form, and be willing to undergo follow-up assessments at the specified time points.
• Ability to communicate effectively with the researcher with the help of a guardian and comply with the researcher's requirements. For young children without mature language skills, ability to cooperate with the help of a guardian.
• The subject's guardian has a correct understanding of the trial and realistic expectations of potential benefits.

Exclusion Criteria:

• Presence of other severe diseases unsuitable for cochlear implantation surgery.
• Significant psychological problems or mood disorders (e.g., notable anxiety, depression, or behavioral disorders) that would preclude cooperation with training and follow-up.
• Neurological diseases (e.g., epilepsy, cerebral palsy) that may affect auditory processing ability.
• Concurrent participation in other interventional studies involving drugs or behavioral interventions that may affect auditory rehabilitation during the study period.
• Any other condition considered by the investigator to make the subject unsuitable for participation in this clinical study.

A single-center, observational cohort of patients across all age groups (children and adults) with severe-to-profound hearing loss who are candidates for and receive cochlear implantation.