Hearing loss

Hearing loss is defined as diminished acuity to sounds that would otherwise be heard normally, ranging from a partial inability to hear to total deafness. It may be present at birth or acquired at any time afterward, and can occur in one or both ears. The condition can be temporary or permanent. In children, hearing problems can impair the ability to acquire spoken language, while in adults they create difficulties with social interaction and work. Age-related hearing loss, which typically affects both ears, results from the loss of cochlear hair cells and can lead to isolation and loneliness, particularly in older individuals. Hearing loss is diagnosed when a person cannot hear sounds at 25 decibels in at least one ear. Severity is categorized as minimal/slight (15–25 dB), mild (25–40 dB), moderate (41–55 dB), moderate-severe (56–70 dB), severe (71–90 dB), or profound (greater than 90 dB). There are three main types: conductive, sensorineural, and mixed hearing loss. Causes include genetics, ageing, noise exposure, infections, birth complications, trauma to the ear or brain, and certain medications or toxins. Chronic ear infections are a common cause, and infections during pregnancy such as cytomegalovirus, syphilis, or rubella can also lead to hearing loss in the child. About half of all hearing loss globally is preventable through public health measures like immunization, proper pregnancy care, avoiding loud noise, and avoiding certain medications. The World Health Organization recommends limiting exposure to loud sounds and personal audio players to one hour per day. Early identification and support are especially important for children. Useful interventions include hearing aids, sign language, cochlear implants, subtitles, and lip reading, though access to hearing aids remains limited in many parts of the world.