Voice recognition technology for persons who have motoric disabilities

Journal of Rehabilitation, April-June, 1994 by Tanya Goette, Jack T. Marchewka

John has quadriplegia. Yet John controls his stereo, opens his refrigerator, turns on his ceiling fan, and manages his architectural firm by using just his voice and a computer. Although this sounds like science fiction, voice recognition technology (VRT) exists today and makes such applications possible.

VRT may provide an important opportunity for accommodating the physically challenged by furnishing an acceptable, if not exceptional, alternative for people who are unable to use a computer keyboard. Some proponents have even suggested that technology may serve as an electronic bill of rights to the physically challenged (Lazzaro, 1990).

Technology, however, is not a panacea. Technology is a tool that must be understood so it may be used correctly to provide an efficient and effective solution for a given problem. To this end, this paper will describe how VRT works, as well as various applications, considerations, and resources for VRT in light of its role for supporting the physically challenged.

The Growth of Adaptive Technology

The Americans with Disabilities Act (ADA) of 1990 was designed to reduce barriers to educate, rehabilitate, and employ individuals with disabilities. The law provides the equivalent of civil rights protection to individuals with disabilities against discrimination and guarantees equal opportunity in terms of employment, education, public accommodations, transportation, government services, and telecommunications.

By law, organizations are required to provide "reasonable accommodation" to make existing facilities accessible to individuals, or to make any modification or adjustment to a job or work environment that would allow a qualified individual with a disability to perform the job.

Adaptive technology (AT) may provide a key that opens doors of opportunity for many individuals with disabilities. Adaptive technology may be an enhancement or modification of information technology (IT) that allows individuals with disabilities to have access to a computer and information, or AT may be designed specifically for use by individuals with disabilities (Lazzaro, 1990). In short, adaptive technology is hardware or software that allows individuals with disabilities to use a computer (Brown, 1992).

For example, individuals who are blind may use speech synthesizers which provide auditory screen reading. Individuals with low vision can use software that magnifies the print on the screen. For individuals with neurologic disabilities several types of adaptations exist. These include word prediction software, software that allows simultaneous keystrokes to be entered consecutively, large keypads, headsticks, and voice recognition software.

Organizations may find that adaptive technology, especially voice recognition software, provides a cost-effective solution for supporting the ADA's directive for "reasonable accommodation". According to the President's Committee on Employment of People with Disabilities, for example, the estimated average cost for furnishing adaptive technology for an employee is less than $1,000 (Rifkin, 1991, p. 25). By providing the needed adaptive technology, employers may remove an individual from disability income and provide the individual with the opportunity for a productive life; thus, the employer may gain a loyal, dedicated, and productive worker while society benefits from the individual's talents, skills, and increased purchasing power. Additionally, the individual contributes to the economy rather than relying on public support which makes adaptive technology a good investment for all.

How Computers Recognize the Human Voice

Voice recognition technology allows a computer to respond to voice commands by sending text to the console of a personal computer much like a standard keyboard. The VRT system may be used with different types of software such as the computer's operating system, word processing, spreadsheets, and database management systems. Commercially available products show improved performance while decreasing in price. Several products exist today that can understand a limited vocabulary of clearly and separately enunciated words.

To use a VRT system the individual must "train" the system to recognize his or her voice. To train the system the user repeats selected words a number of times. A microphone picks up the individual's speech that is in analog or wave form, and the speech waves are broken down into patterns of binary digits by a digital signal processor to represent the vocal sounds of human speech. These binary patterns are compared to a table consisting of the binary patterns of valid words. If a match is found, the spoken word is accepted by the computer (Marchewka & Goette, 1992). Today, the best systems are about 98% accurate, and many universities and businesses are currently looking at ways to improve this technology (Evans, 1988).

Types of VRT Systems

There are three basic types of voice recognition systems: discrete-utterance, connected-word, and continuous speech. Discrete-utterance is the most widely available, and the individual must pause between the uttered words. Pausing between words may become tedious, especially when multiple sentences are required; however, these single utterances are more easily recognized and require less complicated computer hardware than connected-word or continuous speech systems.