Yahoo!'s 20th Anniversary of the American Disabilities Act

In 1990, Congress passed the Americans With Disabilities Act (ADA) to protect the civil rights of the more than 50 million Americans living with disabilities by ensuring their access to jobs, buildings, education, transportation, and telecommunications. To commemorate the 20th anniversary of the ADA's passage, we highlight here some of the assistive technologies that help fulfill the ADA's main intent: to enable disabled people to fully participate in all aspects of their lives.

One of the ADA's purposes is to outlaw job discrimination against candidates and employees with disabilities. It also mandates that all public and commercial buildings provide physical access to those with disabilities. Moreover, all public programs (such as school curricula and public transportation) must be designed so people with disabilities can fully participate in them. And finally, all telecommunication companies must provide alternative services for their disabled customers, such as those who are deaf or speech-impaired.

How does a blind person read a computer screen? And how does a person without hand or finger mobility type on a computer keyboard or use a mouse? The answer: Assistive technologies. By using tools such as screen readers, Braille keyboards, and "touchless keyboards" that enable users to "type" with their forehead (yes, forehead!), people with all kinds of disabilities can use computers at home and in the workplace, too.

Many people are already familiar with closed captioning, which translates the dialogue, narration, and sound effects on TV shows and DVDs into onscreen text that can be read by hearing-impaired viewers. Less familiar is an assistive technology for visually impaired viewers, called Descriptive Video Service (DVS). In using DVS, viewers listen to two separate audio channels simultaneously. In between the dialogue they hear on the primary channel, they hear narration on the secondary channel that describes the visuals appearing on the screen. Some movie theaters also offer DVS.

In select theaters, hearing-impaired moviegoers can use MoPix's Rear Window Captioning System to privately view subtitles while watching a movie. Here's how it works: The moviegoer anchors a reflective plastic panel to their seat's cupholder or to the floor. While the movie plays, large LED captions are displayed in reverse on the back wall of the theater. The moviegoer positions their panel so that they can view the movie screen while reading the reflection of the captions being shown on the back wall. In this way, hearing-impaired moviegoers can see captions for a film that is not already subtitled.

Artificial limbs have been used by amputees for thousands of years, but have had some serious shortcomings. Traditional prostheses have been little more than attachments of dead weight that wearers must swing along with the rest of their body. However, the "smart" arms, legs, hands, and feet that are currently being developed contain sensory receptors that measure the prosthesis's position, the force being applied to it, and the speed of its movement. As for the next generation of prostheses, experts are hopeful that they will be controlled in part by the human brain.

How do you translate Braille text, whose raised dots need to be felt in order to be read, to a smooth touchscreen like that on a cell phone or an e-reader? Cell phone manufacturer Nokia has responded to this challenge using pulses of vibration to represent the raised dots that comprise Braille characters: An intense pulse represents a raised dot, while a series of weaker pulses represents the absence of a dot. Another proposed solution: Use electroactive polymer that, when electrically charged in certain parts of a screen, raises tangible dots to form Braille characters.