Deafness is usually the result of inner ear or nerve damage. It may be caused by a congenital defect, injury, disease, certain medication, exposure to loud noise or age-related wear and tear.The chief symptom is an inability to hear sound.For some, hearing may be possible with surgery or a hearing device. Lip-reading skills, written or printed text and sign language may help with communication.

• Around 466 million people worldwide have disabling hearing loss (1), and 34 million of these are children.
• It is estimated that by 2050 over 900 million people will have disabling hearing loss.
• Hearing loss may result from genetic causes, complications at birth, certain infectious diseases, chronic ear infections, the use of particular drugs, exposure to excessive noise, and ageing.
• 60% of childhood hearing loss is due to preventable causes.
• 1.1 billion young people (aged between 12–35 years) are at risk of hearing loss due to exposure to noise in recreational settings.
• Unaddressed hearing loss poses an annual global cost of US$ 750 billion. Interventions to prevent, identify and address hearing loss are cost-effective and can bring great benefit to individuals.
• People with hearing loss benefit from early identification; use of hearing aids, cochlear implants and other assistive devices; captioning and sign language; and other forms of educational and social support.
• Current estimates suggest an 83% gap in hearing aid need and use, i.e., only 17% of those who could benefit from use of a hearing aid actually use one.