1.04 - Assisted Listening Devices Flashcards
What are ALD’s?
Assistive Listening Devices
What are HATs?
Hearing Assistive Technology
What is Hearing Assistive Technology?
Any device (except a hearing aid or cochlear implant) that helps a deaf or hard of hearing person communicate more effectively.
What are four types of ways that HAT might assist listening?
Direct sound amplification
Text
Visual signals
Vibrotactile signals
HAT is also known as ______.
Assistive Technology (AT)
Assistive Listening Devices (ALDs) is a ______.
Subclass of HAT
Can AT devices be helpful for hearing the TV?
Yes
Can AT devices be helpful for amplifying a lecture for all students?
Yes
Can AT devices be helpful for listening in a confidential meeting?
Yes
Can AT devices be helpful for hearing and seeing a phone conversation?
Yes
Will AT devices probably replace traditional phone conversations for the hearing impaired?
Yes
Can AT devices be helpful for getting text support for a lecture?
Yes
What are the four different varieties of FM systems?
Traditional FM System
Direct Connect of FM to HA
Integrated FM in HA
FM Connected to Cochlear Implant Devices:
What four needs does HAT address?
Effective face to face communication (especially in noise or at a distance)
Access to media
Successful telephone communication
Awareness of alerting signals
Are adults often resistive to HAT?
Yes
What is part of the audiologists job in regards to HAT?
To help client use technology without it being too burdensome
Can HAT be used for Personal Amplification?
Yes
Can HAT be used for Large-Area Amplification?
Yes
Can HAT be used for Telecommunication Options?
Yes
Can HAT provide Signaling/Alerting Devices?
Yes
Can HAT assist with Computer Technology?
Yes
Can HAT be used for Speech-to-Text Transcriptions?
Yes
What is the biggest difficulty faced by individual’s with sensorineural hearing loss?
Hearing Loss in Noise
What determine the difficulty faced with Hearing Loss in Noise?
Difficulty depends on both the individual and listening environment
What does SNR stand for?
Signal to Noise Ratio
What is an Adverse SNR?
The noise is louder than the signal
What four major factors influence speech perception, SNR, and thus, the quality of the speech signal?
Hearing loss
Background noise
Reverberation
Distance
Why is noise so difficult for the hearing impaireed?
Signal to Noise Ratio!
Similarity between the desired signal (speaker) vs. the undesired signal (background noise)
“Noise cannot be defined as a specific spectrum, nor has noise any specific, constant characteristic(s), which can be used to separate it physically from a ______. Noise is a moment-to-moment, qualitative, personal decision for everyone.” (May, Larsen and Warland, 1998)
Desired signal
What is the goal of Assistive Listening Devices?
1+4
To improve the SNR by….
Amplifying speech
Minimizing background noise and its effects
Reducing distance between listener and speaker
Reducing effects of reverberation
What are the classes of ALDs?
Wireless
Hardwired
What are the types of Wireless ALDs?
4
FM systems
Infrared Systems
Induction Loop
Bluetooth
What technology do FM Systems use?
Radio waves, frequency modulated
What technology do Infrared Systems use?
Infrared Light
What technology do Induction Loops use?
3
Electromagnetic transmission
Must have a T-Coil in hearing aid/ CI
Can put a loop around a whole room or have a loop you wear around the neck
Can you put a Bluetooth system in hearing aid?
No. Bluetooth devices interface with HA via t-loop allowing use with most hearing aids
Do several HA companies makes Bluetooth transmitters to work with TV and landline phones? What are the names of those companies?
(3)
Siemens
Oticon
Phonak
What are the Advantages of Bluetooth Systems?
5
Wireless
Short range transmission
Low power, low cost, secure, robust signal
Devices must be paired
Signal will penetrate solid objects. It is all about distance and the pairing
What are the Disadvantages to Bluetooth Systems?
3
Bluetooth is too large to place inside hearing aids/cochlear implants today
Must have a “gateway device” to transfer the bluetooth signal to a different form (FM signal, induction loop) to be received by a hearing aid/cochlear implant
Will not yet replace FM or infrared for use in large areas like auditoriums
Are Personal Wireless FM ALDs even better than digital hearing aids with directional microphones?
Yes
Personal Wireless FM ALDs offer up to ______ improvement in SNR.
15-20 dB
What does 0 SNR mean?
That the signal & noise are the same
What does +10 SNR mean?
That the signal is 10 dB louder than the noise
What does -10 SNR mean?
That the signal is 10 dB softer than the noise
Every ______ of SNR improvement = ______ improvement in speech understanding.
1 dB
10%
Is it exhausting to listen without a good SNR ratio?
Yes
What are the components in Wireless ALDs?
4
Microphone
Transmitter
Receiver
Coupler
What do the Microphone and Transmitter do?
Picks up sound waves and converts to an electrical signal
Sends sound via FM carrier signal, Infrared light, or electromagnetic energy to receiver
What does the Receiver do?
Receiver converts energy back to sound, electromagnetic energy, or electrical signal (Depends of type of Coupler)
What does the Coupler do?
It’s the connection to the Ear
What are some ALD Choices?
4
Headphones
Neckloop
HA shoe
Direct connect cables
Can an FM system travel through walls?
Yes
What are two advantages to using T-coils?
No feedback!
Cuts out background noise
What are some disadvantages to using T-coils?
3
Interference from electromagnetic sources
Gain tends to be weaker
Frequency response (sound quality) of HA may be different than other listening programs
How Does an Induction Loop Work?
4
A sound system or a stand-alone microphone delivers audio to a hearing induction loop driver.
The loop driver is connected to a thin wire (the loop) that is installed around the area where users will need to pick of the signal. The loop driver converts sound into electrical energy that travels through the loop wire.
The loop wire then produces a magnetic field and any t-coil (or telephone coil) within this field will be able to convert the magnetic signal back into sound.
Any area inside this loop is part of the “loop field” and if designed and installed correctly will have a strong, even magnetic field within it.
Is there a limit to the number of t-coil receivers that can use the one magnetic signal?
No
What is a Direct Audio Input (DAI)?
Hard wired system
The user plugs external devices directly into the hearing aid
What are some advantages to DAIs?
3
Usually less interference than with T-coils (computers and some machinery create electromagnetic energy which the T-coil can pick up)
Clearer sound quality
Less distortion due to less transferring of sound energy
What are some Disadvantages to DAIs?
The user is “hardwired” to the device
In addition to having the internal capabilities in the hearing aid, one needs to have the correct cord
Why are Soundfield FM Systems not as popular anymore?
They are big, bulky, and a lot of work
How does a Soundfield FM System work?
Uses a mic and loud speakers
Where do the speakers often sit when a soundfield FM system is used in the classroom?
On the student’s desk
What sorts of students might use an FM soundfield system?
4
Mild or unilateral HL
Central Auditory Processing Disorder
Learning Disability
ADD/ADHD
What types of FM soundfield systems are there?
4
Classroom system
Portable Speakers
Mounted speakers
Desktop system
How do Infrared Systems work?
Uses invisible light waves to transmit sound from the IR transmitter connected to the sound source (TV/radio) to an IR receiver worn by the listener
What types of infrared receivers are there?
IR receiver can be an under-the-chin style or used with a headphone/neckloop
Can infrared systems penetrate walls?
No The receiver must maintain a line of sight to the transmitter because the IR beam cannot penetrate barriers
How are infrared systems powered?
IR transmitter is AC-powered therefore portability is restricted
Can infrared systems work outside?
No. IR cannot work in sunlight
Where are infrared systems often used?
3
Indoor auditoriums
Movie theaters
TV (at home)
What are some advantages to IR systems?
No radio frequency interference
Private
What are some disadvantages to IR systems?
Chin-bar receivers are awkward
Line of sight transmission is necessary
Susceptible to sunlight interference
What are Hard Wired Systems?
One-on-one communicators
Cord connects device to HA / CI
What are some advantages to hard wired systems?
Maintains integrity of HA frequency response
No interference with telecoil
What are some disadvantages to hard wired systems?
Cord connection
Hardwired Devices Independent of HA/CI
What are some factors that can influence ALD selection?
6
Degree of HL
Type of hearing aid
Listening environment
Device features
Cost
Needs and preferences of the listener
How can an individuals Degree of HL affect their ALD options?
Do they have any speech recognition
How does an individual’s type of hearing aid influence ALD options?
Hearing aids have different features
How does an individuals’s listening environment influence ALD choices?
What is the client’s life like?
Do we actually have the means to solve a client’s wants?
What does Other Hearing Assistive Technology refer to?
Technology that is not sound amplification
What sort of HAT is Harkins Movie Theatre now using?
Rear Window Captions
What are four methods of Speech-to-Text Transcription?
4
CART
C-Print
Computer Assisted Note Taking
Voice Recognition Software
What does CART stand for?
Computer Assisted Real Time Translations
What is CART?
3
Stenographic machine connected to a computer (Typist is needed)
Software converts stenographic code into English text
Doesn’t just record the lecture but the other students as well
What is C-Print?
Spoken English is typed using a computer
Abbreviations and condensed text: plez klen the kcn
What is Computer Assisted Notetaking?
Summary of spoken English is typed on computer
No special training require
What is needed with Voice Recognition Software?
Requires training the software to recognize an individual’s speech
What is the goal of Signaling devices?
To provide alternative method of being alerted to environmental sounds
What are three types of Alerting Stimuli?
Visual
Auditory
Vibrotactile
What are is the most common type of Visual Alerting Stimuli?
Flashing light/strobe
What is the are some types of Auditory Alerting Stimuli?
3
Louder volume
Different pitch
Remote receivers to bring sound closer
What are some types of Vibrotactile Alerting Stimuli?
3
Body worn vibrators
Pillow vibrators
Vibrating pagers
What are some issues to consider when choosing alerting stimuli?
(4)
What types of sounds need to be monitored?
How many sounds need to be monitored?
Preferred alerting mode?
Where do monitored sounds occur?
What are some issues to consider when Choosing ALDs?
5
Degree of hearing loss
Compatibility with exisiting phone
Compatibility with existing hearing aids
Presence/absence of a t-coil on HA.CI
Portability, flexibility, & cost
