Assistive Devices for People with Hearing, Voice, Speech, or Language Disorders

Hearing loop (or induction loop) systems use electromagnetic energy to transmit sound. A hearing loop system involves four parts:

• A sound source, such as a public address system, microphone, or home TV or telephone
• An amplifier
• A thin loop of wire that encircles a room or branches out beneath carpeting
• A receiver worn in the ears or as a headset

Amplified sound travels through the loop and creates an electromagnetic field that is picked up directly by a hearing loop receiver or a telecoil (see sidebar), a miniature wireless receiver that is built into many hearing aids and cochlear implants. To pick up the signal, a listener must be wearing the receiver and be within or near the loop. Because the sound is picked up directly by the receiver, the sound is much clearer, without as much of the competing background noise associated with many listening environments. Some loop systems are portable, making it possible for people with hearing loss to improve their listening environments, as needed, as they proceed with their daily activities. A hearing loop can be connected to a public address system, a television, or any other audio source. For those who don’t have hearing aids with embedded telecoils, portable loop receivers are also available.

Improved devices for nonspeaking people

• More natural synthesized speech
  NIDCD-sponsored scientists are also developing a personalized text-to-speech synthesis system that synthesizes speech that is more intelligible and natural sounding to be incorporated in speech-generating devices. Individuals who are at risk of losing their speaking ability can prerecord their own speech, which is then converted into their personal synthetic voice.
• Brain–computer interface research
  A relatively new and exciting area of study is called brain–computer interface research. NIDCD-funded scientists are studying how neural signals in a person’s brain can be translated by a computer to help someone communicate. For example, people with amyotrophic lateral sclerosis (ALS, or Lou Gehrig’s disease) or brainstem stroke lose their ability to move their arms, legs, or body. They can also become locked-in, where they are not able to express words, even though they are able to think and reason normally. By implanting electrodes on the brain’s motor cortex, some researchers are studying how a person who is locked-in can control communication software and type out words simply by imagining the movement of his or her hand. Other researchers are attempting to develop a prosthetic device that will be able to translate a person’s thoughts into synthesized words and sentences. Another group is developing a wireless device that monitors brain activity that is triggered by visual stimulation. In this way, people who are locked-in can call for help during an emergency by staring at a designated spot on the device