The Future of Children, Princeton - Brookings: Providing research and analysis to promote effective policies and programs for children.

Students with hearing impairments are those who have a hearing loss that interferes with their ability to process linguistic information through auditory channels with or without amplification.⁴¹ The most recent data available from the U.S. Department of Education indicate that 1% to 2% of students ages 6 to 17 enrolled in special education programs in the United States have hearing impairments, and that a small fraction (0.02%) of these are both deaf and blind. In all, about 66,000 students have been diagnosed with some type of hearing impairment that interferes with their ability to function without some type of assistive device.³⁸

Any device that is used to enhance a person's residual hearing is referred to as an assistive listening device (ALD). Beyond ALDs, telecommunications devices have been created to assist students with severe hearing impairments by making use of other abilities, such as sight and touch. ALDs have been used since the 1800s. At that time, horns were held to the ear to collect and focus sound waves. Certain pitch ranges were amplified, depending on the dimensions of the horn, and no external power supply was used. One of the first high-tech devices designed for persons with hearing impairments is something we take for granted—the telephone. Alexander Graham Bell originally invented the telephone for the purpose of helping his sister, who had a hearing disability. Today, advances in computer technology and medicine have led to the development of a wide range of hightech ALDs and telecommunication devices that assist students with severe hearing impairments, enabling them to participate more effectively in the classroom (see Box 1).

Two telecommunication devices that assist students with severe hearing impairments and that have become commonplace in American society are the Telecommunication Device for the Deaf (TDD) and "captioning." TDDs allow users to use a keyboard to type and receive messages over the phone lines; captioning refers to the addition of text to a visual display, where the words that are spoken are seen as text. Although TDDs are devices that primarily enhance the lives of students with hearing impairments outside of school, captioning has been found to be especially helpful in promoting the inclusion of students with hearing loss in the regular classroom environment. For example, video captioning and captioned educational programs have proven to be very helpful in motivating students with hearing disabilities to learn to read. Because the nature of a hearing loss tends to cause language and communication problems, particularly in understanding situations, conversations, and written materials, studies indicate that the average reading levels of students who are deaf are considerably lower than the levels of their hearing peers of similar intellectual ability.⁴² Research has demonstrated, however, that captioned video and television programs can help deaf students improve their vocabulary and reading comprehension, and promote deeper levels of understanding of what is taught in the classroom.⁴³

Today, a large percentage of broadcast television is captioned, providing individuals with hearing impairments equal access to public information and entertainment. But while most programs on national networks and cable television channels—as well as thousands of movies and documentaries —are captioned, fewer than 10% of educational videos were captioned as of 1998.⁴⁴ Increased captioning could expand classroom opportunities and enhance reading instruction for students with hearing loss.⁴⁵