Hearing impairment is a reduction in the ability to perceive sound and can be present from birth or develop later in life. It affects over 34.5 million adults in the United States. Causes can include heredity, disease, trauma, certain medicines, and long-term loud noise exposure. Treatment depends on the cause but may include removing earwax, medication, surgery, hearing aids, cochlear implants, and therapy. Teachers can help students with hearing loss by using visual aids, speaking clearly, writing concisely, and ensuring good seating. Interpreters and technology can also assist communication for deaf students. However, for some cases restored hearing may not be possible.