Hearing loss is the partial or complete loss of hearing. Hearing loss can occur in one or both ears and can be temporary or permanent. Hearing problems in children may interfere with language learning and may cause difficulties at work for adults. For some people, especially the elderly population, hearing loss may cause isolation, we will focus on hearing loss in the elders. Presbycusis, or age-related hearing loss, refers to the gradual deterioration of the hearing system with age. Approximately one third of people over the age of 65 have a hearing impairment, and more than half of those over the age of 75 have a hearing impairment. This does not include hearing loss that may be caused by tumors, neurological or autoimmune diseases, or some other factors that can be easily corrected. Even mild hearing loss can cause difficulty understanding speech and cause seniors with hearing loss to exhibit certain abnormal behaviors. For example, an elderly person with a mild hearing loss may avoid communicating with others. Speech comprehension may be more difficult when there is ambient background noise or when multiple people are speaking at the same time, such as in a restaurant or at a family gathering. Constantly requiring others to speak loudly in order to be heard can, in turn, cause frustration for both the speaker and the listener. Seniors with hearing loss may misunderstand questions, often giving a bizarre answer that confuses others. They may misjudge the volume of their own speech and thus shout, causing a sense of discouragement in others with whom they are speaking. As a result, hearing loss can lead to social isolation, reluctance to participate in social activities, loss of social support and depression in older people. For people with dementia, hearing loss can make communication more difficult. Correcting hearing loss in a timely manner has significant benefits for physical and mental health. Because age-related hearing loss is age-related. It may be the result of deterioration in auditory function due to aging and the interaction of lifelong noise exposure. Age-related deafness is mostly bilateral sensorineural deafness, which is almost identical bilaterally and shows slow progressive exacerbation. Hearing loss is usually manifested as a decline in hearing to high frequency sounds, usually occurring between the ages of 55 and 65 (sometimes earlier), the elderly first become insensitive to high frequency sounds such as doorbells, telephone ringing, bird sound, etc., and gradually become less sensitive to all sounds. The loss of high-frequency hearing, in turn, is reflected in a decline in the ability to understand speech. Even if the overall loudness of speech sounds normal, an overly noisy background can make speech more difficult to understand. The main symptom is the difficulty in distinguishing between sounds that can be heard, and the decline in comprehension. This symptom initially appears only in special environments, such as public places where many people are talking at the same time, but it gradually worsens and causes difficulty in talking to others, and the elderly gradually become reluctant to speak and become lonely. Some elderly people may also experience the phenomenon of resonance, i.e. they can't hear well when they speak quietly and find it too noisy when they speak loudly. Their ability to judge sound sources decreases, and sometimes they will compensate by using visuals, such as paying special attention to the face and lips of others when they speak with them. Most of the elderly people also experience some degree of tinnitus, which is usually high pitched and starts only in the middle of the night and gets worse gradually and lasts all day long.