2000 Conference Proceedings
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An Overview of Hearing Assistance Technology
David Baquis
Director, SHHH National Center on Assistive Technology
Although people with hearing loss comprise the largest
disability group, their needs are poorly understood and often
go unaddressed. This lack of awareness is prevalent both inside
and outside of the disability community. Those who attempt to
meet the needs of people with hearing loss need to consider the
diverse needs of individuals, who experience hearing losses
ranging from mild to severe and who use a variety of
technologies to help them cope.
This is not an insignificant group. There are an estimated 28
million people with hearing loss in America, which is 10% of
the population. The number of people with hearing loss is
predicted to rise significantly as the aging baby boomer
generation enters middle age – the time when hearing loss
incidence increases.
Although hearing loss affects one in three older people, it is
a concern to younger people as well, especially working-age
hard of hearing adults who are unemployed. Many of those adults
can be helped with a combination of advocacy, technology and
communication strategies.
There are many ways of coping with hearing loss. Assistive
technology is just one strategy. Other resources include: using
hearing aids, when recommended; participating in hearing loss
support groups; and reading educational publications with
information on subjects such as stress control and personal
advocacy.
A needs assessment is an important precursor to learning about
hearing assistance technology. The assessment anticipates
different situations where hearing can be challenging and uses
questions to help determine an individual’s areas of
difficulty. It is important to begin with various questions
about someone’s challenges to prevent overlooking
problems that consumers forget to ask about. For example, they
may inquire about a telephone amplifier to better understand
conversations. When this problem is presented, it also becomes
useful to know if they miss phone calls and need a telephone
ring signaler.
Introduction
Assistive technologies help people with hearing loss acquire
greater confidence in their communication skills, expand their
abilities to maintain independent lifestyles and reach their
full potential scholastically, professionally and socially. An
important challenge to overcome, however, is lack of awareness
about what devices and services are available.
Assistive technology is a broad term that encompasses both
devices, such as TTYs, as well as related support, such as
relay services. Other services include: equipment distribution
programs; assistive device demonstration centers; financial aid
programs and legal advocacy services.
Some devices, such as flashing wake-up alarms, were
specifically designed to help someone with hearing loss. Other
devices, such as personal computers, were originally developed
for general purposes, but nevertheless afford important
secondary benefits to people with hearing loss. Hearing
assistance technologies can be grouped into three categories:
listening devices, telecommunications, and alerting
devices.
Listening
An assistive listening system (ALS) is designed to amplify and
clarify sound by reducing the effect of distance between the
user and the sound source. Such systems can also help minimize
background noise and can help compensate for poor acoustics.
There are three types of ALS technologies: inductive loop,
infrared and FM. Loops transmit an electromagnetic field,
infrared systems emit light waves, and FM systems send radio
waves. Each works well, operates without wires, and can be used
with or without hearing aids. An array of receiver attachments
is available to meet varying individual needs and listening
preferences.
People who use a hearing aid equipped with a telecoil may
prefer an inductive loop, since they will not need additional
receivers; instead, users simply switch their hearing aid to
the T position. Infrared systems offer the advantage of
privacy. Such systems might be a good choice for courtroom
situations because the light waves they transmit don’t
pass through walls. FM systems are portable, making them a
popular choice for classroom situations, since both the teacher
and student can use battery-operated components, and the
student can move around without interfering with
reception.
All three systems are susceptible to interference. Loop
systems are occasionally affected by electromagnetic fields,
but some sources, such as computer monitors, can be turned off
at times. Sunlight or certain fluorescent lights can affect
infrared systems, but a more powerful emitter and a newer model
receiver may help compensate for that. Pagers and other radio
transmitting devices may affect FM systems, but changing FM
frequencies may help.
One key to successful use of any ALS in a meeting situation is
effective placement of microphones. For example, during a large
meeting, one microphone might be used by a primary speaker,
with audience members asked to use side microphones. A cordless
FM microphone could also be passed around as needed. For a
medium size meeting, the tables could be equipped with a single
microphone for every two or three people. Conference
microphones, which pick-up the speech of several people in the
vicinity, are also available.
For a small meeting (three to four people) a personal
listening device may be effective. It involves connecting both
a microphone and listening attachment to the same device, an
amplifier. This offers two advantages: it is relatively
inexpensive (approximately $200) and portable (the size of a
deck of cards). Such a device is often used for one-to-one
conversations, such as when driving a car or when speaking to a
doctor. This is not wireless, so could not transmit across a
distance, although in some cases it can be used with several
microphones.
Telephone
People with hearing losses can get information by phone in one
of two ways: amplification or text. There are four types of
amplifiers: portable, in-line, handset and phone set. Portable
amplifiers strap onto the telephone handset. They are
convenient for travel but are not usually practical for regular
use.
In-line and handset amplifiers are the most popular choices
because they are relatively inexpensive and generally equal in
effectiveness. Most amplifiers designed for hard of hearing
people offer a 20dB gain, although devices with gains up to
40dB are also available. Some amplification phones offer a
differential boost in volume, resulting in a reduction of
"muddling" sounds for some users because the low frequencies
are not amplified as much as the high ones. Telephone products,
such as these, are sometimes available free of charge through
equipment distribution programs.
Electronic incompatibility can be a problem: Some
amplification handsets do not work on certain phones as
evidenced by a buzzing sound or the inability of one party to
hear the other. The problem sometimes occurs at hotels, which
loan amplifiers to customers, to use with their room phones.
The cause is related to the type of handset microphone and
circuitry being used. The solution may involve obtaining a
universal amplifier, which is designed to work with most types
of phones.
TTYs allow users to read the text of their phone
conversations. One option is for both parties to use a TTY.
However, this text telecommunications approach can be used,
even when the hearing party doesn’t have a TTY. In this
case, a telecommunications relay service will use a
communication assistant to bridge the gap by typing the hearing
party’s conversation into the TTY. Instead of typing, a
hard of hearing person with good speech can use a relay service
option called "voice carry over" to respond orally. Some TTYs
specifically designed for voice carry-over do not include a
keyboard.
Cellular phones offer users both convenience, and security.
Accessible cellular phones will be hearing aid compatible;
provide amplification and feature an audio jack, allowing
connection to attachments for listening through both ears. Hard
of hearing consumers also desire a vibrating ringer, available
on select models. Digital wireless phones have generally not
been shown to work reliably with hearing aids or TTYs at this
time, although the industry is working towards a solution for
both.
Other telecommunication devices, which provide parity for hard
of hearing people, include: fax machines, pagers and integrated
wireless products (which may combine fax, pager, TTY and
e-mail). Most pagers can vibrate and some display the text of
messages. The Internet is especially a boon to hard of hearing
people because it can be used for instant messaging, conference
calling and e-mail.
New developments in text telecommunications include
videophones, text based office intercom systems and TTY
accessible interactive voice response systems.
Some of the optional services offered by local phone companies
hold advantages for people with hearing loss. Caller
identification, for example, allows consumers to see the number
of a caller on a TV or display box and to return that call
through a relay service. Distinctive ringing allows households
with both hearing and hard of hearing members to dedicate one
number for TTY use and the other for voice calls. Voice mail
service allows consumers to listen to messages using
amplification devices. These custom calling features require an
additional monthly fee.
Television
Like the telephone, there are two ways to know what is said on
TV: reading captions or listening through amplification. With
regard to captioning, all TVs, 13 inches or greater, sold and
manufactured in the U.S. must have closed caption capability.
Older TVs can be modified through the use of a telecaption
decoder. The Telecommunications Act of 1996 requires captioning
for many of the TV programs and videos being produced.
With regard to amplification, it is also possible to connect
inexpensive assistive listening systems to the TV. These allow
consumers to hear sounds more clearly without interfering with
the enjoyment of other listeners. ALSs can also be used with
stereo systems.
Alerting
Smoke alarms, a telephone ringing, doorbells, a baby crying,
wake-up alarms and security systems are some of the sounds that
can be transmitted to a person with hearing loss through an
alerting device. The most commonly used systems employ loud
ringers, flashing lights or portable vibrators and can range
from relatively simple to very sophisticated. A simple,
inexpensive telephone light flasher will only be visible at the
site where it is installed. A more comprehensive system could
signal a consumer to a variety of events through use of
transmitters placed at various points in the house.
Another signaling device, a personal pager is only about $80.
It allows a user to alert someone in the vicinity (via tone or
vibration) and does not require a monthly fee, as do
telecommunications pagers.
Two types of alerting devices are available to help hard of
hearing drivers. One is an emergency siren indicator that
flashes a panel of small lights on the dashboard to signal the
approach of an ambulance, fire engine, or police car. The other
is a turn signal reminder that flashes a light or makes a
progressively louder sound if the driver forgets to turn the
signal switch off. In the United States, four car manufacturers
have offered to reimburse users for the cost of buying and
installing one or both of these devices.
Advocacy
Advocacy is an important component with regard to the effective
use of assistive technology. Consumers must understand
governing public policies and exercise their rights to acquire
and use assistive technology. For example, in the United
States, the Americans with Disabilities Act (ADA), mandates
that reasonable accommodations be made available to persons
with a hearing loss in the workplace, local and state
government agencies and public arenas. It is important for
consumers to make use of resources already in place since this
is one of the best way to support advocacy efforts to improve
public accommodations.
Unfortunately, hard of hearing consumers often miss out
because they feel uncomfortable asking for assistance. It is
often in commonplace situations, such as Thanksgiving meals,
weddings, funerals and graduation ceremonies, that hearing
access is most valued. Membership in consumer groups, such as
SHHH, helps consumers learn assertiveness skills and become
comfortable using assistive listening devices.
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