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Texas School for the Blind and Visually Impaired
Outreach Programs
www.tsbvi.edu | 1100 W. 45th St. | Austin, Texas 78756 | 512-454-8631
Hearing Technology and
Orientation & Mobility
Susie Tiggs, M.Ed.
ESC Region XI
Hearing Technology and Orientation and Mobility, TETN 11.15.2012
Three Types of Hearing Loss
Conductive Loss

Due to problems with the ear canal, ear drum, or middle ear and its little bones (the
malleus, incus, and stapes)

Low frequency loss or equal across frequencies

Tend to talk softer than usual or with normal intensity

Hear own voices through bone conduction but don’t hear competing noise

May hear better in loud, noisy environments because background noise reduce by the
conductive problem, and other people speak louder to be heard over the noise
Sensorineural Loss

Due to problems of the inner ear, also known as nerve-related hearing loss.

Audiograms sloping curves

Typically more severe at the upper frequencies

Increased volume alone doesn’t make up the deficit

Generally speak louder to others to be able to hear own voices • Use residual vision to
see speaker’s gestures, face, and lips
Mixed Loss

Combination of conductive and sensorineural hearing loss

May be damage in the outer or middle ear and in the inner ear (cochlea) or auditory
nerve

Characteristics of both mixed and sensorineural hearing loss
Audiograms
Intensity or loudness- measured in decibels (dB)

Whisper approximately 30 dB

Conversations usually 45-50 dB
Frequency or pitch-measured in hertz (Hz)

Vowel sounds like "u" have low frequencies (250 to 1,000 Hz)

Consonants like "s," "h," and "f" have higher frequencies (1,500 to 6,000 Hz)
Traffic sounds

Quiet residential area – 72 dB

Downtown metropolitan area – 84 dB
Hearing Technology and Orientation and Mobility, TETN 11.15.2012
Mild Hearing Loss – 26 to 40 dB Loss

Understands conversational speech at a distance of 3-?5 feet (face to face)

May miss as much as 50% of class discussions if voices are faint or speaker is not in line
of vision

Difficulty following directions

Frequently asks for repetition

Conversation outside masked by traffic sounds
Moderate Hearing Loss – 41 to 70 dB Loss

Conversation must be loud to be understood

Will have increased difficulty in group discussions

Is likely to misinterpret verbal directions

May benefit from hearing aids

Conversation outside masked by traffic sounds
Severe Hearing Loss – 71 to 90 dB Loss

May detect loud voices

May be able to identify environmental sounds

Need visual cues (speaker's face and especially lips) to understand even part of any
conversation

Impossible to function in difficult listening situations such as in groups or in noise
Profound Hearing Loss – 91+ Loss

May detect loud sounds (probably vibrations)

Relies on vision rather than hearing

Hearing aid may not help much

Won’t hear traffic sounds
Unilateral Hearing Loss – Loss in one ear

May have difficulty hearing faint or distant speech

Difficulty localizing sounds

Difficulty detecting or understanding soft speech (especially on side with deaf ear)
Sound Meter Apps

Available for iOS and Android

Free or inexpensive

Use to determine the loudness of the area you will be working in
Hearing Technology and Orientation and Mobility, TETN 11.15.2012
AMPLIFICATION
Conventional Hearing Aids

CAN:
o Make all sounds in the environment louder: speech sounds, the?ventilation system,
the TV, the birds chirping?

CANNOT:
o
o
o
o
o
"Cure" a hearing loss
Create new hair cells
Help the child hear sounds at frequencies or pitches at which
she has no hearing
Make sounds clearer
Digital Hearing Aids

Computer chip inside

Can be individualized to the user’s audiogram

Can be programmed to mask background noise
Bone Conduction Hearing Aid (BCHA) and Bone Anchored Hearing Aid (BAHA)

Bypass the outer and middle ear o Directly stimulate the cochlea

Use bone conduction to transmit sound
Cochlear Implant

Surgically implanted in the cochlea of an ear with a profound hearing loss

External parts:
o Sound processor with microphone?
o Transmitter system?

Internal parts:
o Receiver – surgically placed under skin
o Electrode array – from receiver to cochlea

Does not restore normal hearing

Helps create a useful representation of sounds in the environment
Cochlear Implant Considerations

Generally unilateral

Hard to localize sound

Background noise masks conversation

Easy to overestimate safety
Hearing Technology and Orientation and Mobility, TETN 11.15.2012
Assistive Listening Devices - (ALD)

Microphone/Transmitter – worn by speaker

Receiver – attached to hearing aid
Microphones

Directional microphones
o Sounds from front of hearing aids 45 degrees
o Tunes out sounds from behind and side – traffic

Omnidirectional microphones
o Sounds 360 degrees
o Conversation lost in background noises

Best if two microphones at ear level for localization
Gain

Increase in loudness

May be different at each frequency

Allows the hearing aid to compensate for losses at specific frequencies

Distorts true traffic noises so hard to judge distance
Compression

Amplifies softer sounds more than louder sounds

Automatically adjusts the amount of gain so that loud sounds won't be distorted or too
loud

Distorts environmental sounds so hard to judge distance
Digital Programming

Store more than one listening program in the hearing aid circuit o Choose different
microphone or hearing aid settings

Remote control or program button on the hearing aid

Use different programs for listening in noisy situations or when listening to TV or music
Auditory Training
Teaching to take full advantage of auditory cues o Developing awareness of sound

Gross discrimination of nonverbal stimuli

Gross and fine discrimination of speech
Auditory training – O&M

Include as part of the plan for developing auditory skills for orientation and mobility
Hearing Technology and Orientation and Mobility, TETN 11.15.2012

Provide auditory training as part of active travel lessons in natural settings

Teach the sound as well as how to use the sound

Sound Discrimination
o Ability to distinguish between sounds.
o Learn these skills by having repeated opportunities to hear everyday environmental
sounds and pairing them with their sources

Sound localization
o Ability to determine where sounds are coming from
o Identify distance of sound
In Summary

Become familiar with the student’s audiogram

Learn about the student’s amplification

Use sound meter level

Include auditory training

Team up with the deaf ed teacher
Questions?
Susie Tiggs, M.Ed.
Education Service Center Region XI
stiggs @ esc 1 1 .net
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Hearing Technology and Orientation and Mobility, TETN 11.15.2012