1. Hearing Aids and Hearing Assistance Technologies
Chapter 7
Hearing Aids
and
Hearing Assistance Technologies

2. Purpose of Listening Devices
Make speech audible
Make non-speech audible
Restore range of loudness

3. Hearing Challenges Hearing soft speech Hearing speech clearly
Hearing speech in noisy environment
Hearing speech in reverberant environment

4. Definition of Hearing Aid
Hearing Aids (noun, plural) 1 (archaic): electronic devices usually worn by a person for amplifying sound before it reaches the auditory receptor organs. 2 (modern): electronic devices worn by a person for processing sound to provide audibility and improve the signal-to-noise ratio before it reaches the auditory receptor organs.
A New Definition for Modern Hearing Aids, Victor Bray, Ph.D. & Michael Nilsson, Ph.D., Auditory Research Department, Sonic Innovations, Inc.

5. Types of Listening Devices
Hearing Aids
ALDs/HAT
Alerting Devices
Brainstem Implants
Bone Anchored Hearing Aids (BAHA)
Cochlear Implants (CI)

6. Hearing Aid Styles Air conduction Bone Conduction
Body Aid
Glasses
BTE
RITE
RITA
ITE
ITC
CIC
Bone Conduction
Bone Anchored (BAHA) (above 20 years) (now considered a mastoid implant)
              

7. Open Canal
Receiver in the Ear
RITE
Receiver in the Aid
RITA

8. Bone conduction HA
When a conventional hearing aid cannot be worn due to microtia, atresia, obstruction in EAM, bone conduction hearing aids may be beneficial

9. BAHA Bone Anchored Hearing Aid:
Surgically embedded titanium "post" into skull with a small abutment
A sound processor sits on abutment
The implant vibrates the skull and stimulates the cochlea via bone conduction bypassing outer & middle ear
Treatment for:
Conductive loss
Mixed hearing losses
Unilateral sensorineural hearing loss,
Chronic ear infections
Congenital external auditory canal atresia

10. Hearing Aids Analog (conventional) Programmable (analog or digital)

11. Type of Hearing Aids
Analog
hearing aids pick up the sound and convert it into electronic signals. These hearing aids have trimmers that are manually adjusted by a hearing healthcare professional using a tiny screwdriver. Analog hearing aids are the least flexible, but also the least expensive, level of hearing aid technology.
Programmable
Programmable hearing aids must be connected to a computer in order for your hearing healthcare professional to make adjustments. These hearing aids offer more flexibility and can provide more features.
Digital
Digital hearing aids contain computer chips that convert the electronic signal into digital signals. The digital hearing aid can perform complex processing of the sound, such as reducing the intensity of loud background noise. Typically programmed via a computer, offers the greatest flexibility in its ability to match the hearing aid response to the hearing loss.

12. HA Components
Microphone The microphone picks up sounds from the air and convert them into electrical signals. Amplifier The amplifier increases the intensity of the signals from the microphone. Filters modify the sounds so that only sounds which are relevant for the person are amplified. 'Loudspeaker' (Receiver) The third basic component is the 'loudspeaker' (receiver). It converts electrical signals into acoustic signals, which the person then hears. Small computer (Digital) (How it works) These three components exist in all hearing aids. Furthermore, in digital hearing aids a small computer can be programmed to manipulate the signals to fit the hearing loss of the individual hearing-impaired person.
              

13. Batteries
Various Sizes
Chemical

14. Earmolds Earmolds direct sound into the ear canal
Variety of styles, colors, and other characteristics

15. Verification of HA Real Ear (probe microphone)
Speech tests (HINT, QuickSIN, BKB-SIN, SPIN)
Subjective ratings of intelligibility and quality
Loudness verification
Questionnaires
Functional gain
ABR—for infants & young children

16. Probe Microphone
Real Ear measures of sound pressure in the ear canal

17. Speech Tests
HINT
QuickSIN
BKB-SIN
SPIN

18. QuickSIN/BKB-SIN
1.   SNR loss of 0-2 dB: Normal to near-normal.  These patients will probably do well in noise with any hearing aids that provide undistorted output.  With directional microphones, they may hear better than their normal-hearing peers in noisy situations.
2.  SNR loss of 2-7 dB: Mild SNR loss.  Today’s directional microphones provide SNR improvements of 2 to 5 dB; with directional microphones, these patients should be able to hear almost as well as their normal-hearing counterparts in noisy situations.
3.  SNR loss of 7-15 dB: Moderate SNR loss.  While directional microphones will provide benefit for these patients, they cannot provide enough SNR improvement to allow the person to hear as well as their normal-hearing counterparts in noisy situations. Microphone arrays, such as the LinkiT, provide a 7 to 13 dB improvement in SNR.
4.  SNR loss greater than 15 dB: Severe SNR loss.  These patients need the maximum amount of SNR improvement, and FM systems are the technology of choice for these patients. Today’s ear-level FM systems are cosmetically appealing and are available in a wide range of hearing aids. Contact hearing aid manufacturers for more information.

19. Subjective Ratings Magnitude Production Category Scaling
Pt is given a number and instructed to adjust a given parameter such as intensity, SNR, until that number is reached
Category Scaling
Pt is given a bounded scale such as 1 to 10 and asked to make a judgment of a speech passage based on intelligibility, quality, etc.
Paired Comparisons
Pt compares 2 different settings or hearing aids
Clarity
Pt asked to judge if sound is clear, distinct, pure…the opposite is diffuse

20. Loudness Restoration
PAL
Soft, comfortable, loud

21. Functional Gain Compare Aided vs. Unaided results
In the example, the aided (green) thresholds are compared to the unaided thresholds for the right (red) and left (blue) thresholds

22. Questionnaires
APHAB
PAL

23. Binaural vs. Monaural Advantage
head shadow
loudness summation
localizing
signal to noise ratio

24. ALDs/HAT

25. ALDS/HAT Loop Induction (Loop)(Electromagnetic) Radio FrequencyAM FM
FM plus Video
BlueTooth
Light (Infrared)

26. Loop Induction Systems
ALDs/HAT
Loop Induction Systems

27. Looping the World with Audiocoil
“The ordinary telecoil is perhaps the most common and most underestimated assistive listening device available for hearing impaired individuals today.”
Ross (2002).
“By changing the label to something more general—my suggestion is ‘audiocoil’—we do not restrict to a single function the way we think of the coil”.
Ross (2006). Telecoils are about more than telephones. The Hearing Journal, 59,

28. LI Components
Microphone
Loop amplifier
Loop wire
Telecoil

29. Loop Inducton
Large area
Home area (cushion loop pad)

30. Loop Options Silhouette: Neckloop: Portable Loop
Near telecoil and signal relatively low therefore less susceptible to) most EMI (ElectroMagnetic Interference).
Stay aligned relative to the hearing aid, they are less sensitive to head position.
Neckloop:
Drive both hearing aids (not with true stereo, but with a mono signal into both aids).
Does not require wires running up the neck to the hearing aid(s), and can be worn under a shirt or jacket.
Portable Loop
Portable and able to carry
Communicate one on one or in small groups, cars, etc.

31. Loop Induction Oval Window
LI transmits via an electromagnetic field and require no receiver if the hearing aid wearer has a telecoil
Oval Window

32. Loop Induction: Telecoils
Inductive/audio loop systems transmit an electro- magnetic field
Receivers are not necessary for hearing aid wearers with a telecoil (the telecoil itself is the receiver)
Loop receivers can be provided for people who do not have telecoils.
Loops are often permanently installed
Silhouette inductor
Neckloop
Direct audio input

33. Radio Frequency Systems
ALDs/Hat
Radio Frequency Systems

34. Radio Frequency
FM (radio frequency) systems transmit radio waves to receivers
Used in classrooms and where mobility is required
Not affected by light, able to cover 100+ feet, and are portable
Systems can be set to different frequencies to allow several uses in same place
Miniaturized FM receivers using the mhz range are available as an attachment for some BTEs and CI processors
Some FM transmitters have built-in microphones that can switch from an omnidirectional, directional and/or super directional setting
Susceptible to some radio interference

35. Radio Frequency Systems
Phonak
Multi-frequency receivers (MLxS, ML8S and ML9S)
synchronized automatically using the WallPilot or directly with Campus S. The MLxS also has a standardized connector that makes it compatible with both Phonak hearing instruments and BTEs from other manufacturers
Single-frequency receivers (MLx, ML8, ML3-7)
single-frequency receiver which clips to BTE hearing aid
MicroLink CI S
miniaturized FM receiver for cochlear implant users that attaches directly to the bodyworn speech processor
WallPilot
hangs at the entrance to a room and performs an Automatic Frequency Synchronization (AFS) and ensures that the multi-frequency receivers of wearers entering the room are automatically set to the correct frequency

36. Phonak iLink

37. Phonak SmartLink

39. FM Radio Frequency Systems
Phonic Ear
Sprite BTE FM
used by people of all ages who have hearing abilities ranging from normal to profound loss used in the car, at restaurants and parties, watching TV, on tours, and talking with others across a distance.
students with ADD or CAPD benefit
Toteable

40. Oticon

41. AVR

42. BlueTooth
Bluetooth is a short-range, wireless, digital communication standard.
Bluetooth devices send data and voice in a clean, clear, digital format
audio signal is not subject to the same sources of signal degradation that sometimes compromise the quality of analog (FM, AM or inductive) transmissions.
Radio frequency transmission in the 2.4-gigaHertz range

43. BlueTooth Advantages
Bluetooth signal is extracted from the noise; it alone is transmitted and amplified, while noise is rejected.
Minimizes battery consumption for portable devices
Also, it places an intentional limit on the range of transmission — the most common version has a range of 10 meters which helps to avoid interference among nearby devices
Walls and other obstacles have a negligible effect on Bluetooth transmission

44. BlueTooth Interference Advantage

45. Starkey

46. ELI

47. ALDs/HAT
Infrared Systems

48. Infrared
Infrared systems transmit sound via infrared light waves to receivers worn by users
IR commonly used in courtrooms, movies, and live performance theaters, conventions and with TVs (signal contained in room)
Infrared systems may be susceptible to interference from bright sunlight or fluorescent lights
Requires line-of-sight between the IR transmitter and the receiver, IR waves can effectively reflect off some surfaces, depending upon the power of the transmitter
                      

49. Audiovisual FM AudiSee
Assistive device to facilitate speechreading and hearing, primarily in educational settings
Portable
Camera and microphone worn by speaker
less strain to speechread when teacher moves about the classroom or turns to write on the blackboard

50. Sound Field Systems
Portable or permanently installed speakers placed close to listeners at a distance from the speaker
They are most often used in classrooms and are helpful for people with mild to moderate loss
They offer a secondary benefit to those who are not HOH
Wireless speakers perform the same function.
Audio Enhancement Video 1
Audio Enhancement Video 2

51. Vibrotactile Devices
Tactaid - small, battery-powered instruments that can help a deaf person understand sounds by allowing the user to feel the unique pattern of vibrations present in every sound

52. Hearing assistive technology (HAT)
refers to devices and services that help deaf and hard of hearing people compensate for their hearing loss
four primary categories of technology:
assistive listening devices
alerting devices
telecommunications devices
visual communication devices

53. ALDs/HAT Function Catch the desired sound as cleanly as possibly
(using well-selected microphones or a direct audio feed)
Carry the sound intact via a specific type of transmission to a receiver
(using infrared light waves, radio waves, induction, or wires)
Couple the receiver to the hearing device or ear with as little background noise, feedback or distortion as possible
(using neckloops, silhouettes, cords, headphones, or earbuds, depending on the user's equipment or lack thereof).

54. How ALDs/HAT Help Bypassing or minimizing background noise
Overcoming the weakening effect of sound traveling through air
Reducing the effect of poor room acoustics

55. ALDs (HAT)
assistive listening devices and systems (including couplers and accessories for hearing aids and cochlear implants)
alerting devices and systems (weather, doorbell, phone, fire/smoke alerting devices)
amplified telephones (some of which have tone controls and/or audio output jacks) and telephone accessories
TTYs (teletypewriters), VCO (Voice Carry Over) phones, CapTel, and telecommunications-related software and services
speech-to-text services and technology, such as CART (Computer Assisted Realtime Transcription), C-Print and CAN; closed caption decoders
videophones and other visual technology to facilitate speechreading and/or the use of sign language or cued speech

56. TELECOMMUNICATIONS
Television
Telephones
POTS
Cell Phones

57. TELECOMMUNICATIONS: TV
Television
There are two ways to understand communication on TV: hear it or read it:
closed captions, a menu option ability built into most TVs (TVs over 13 inches in diameter sold after 1993).
ALDs
Increase volume on a personal receiver, not TV sound across the room
Most are cordless and utilize different types of technologies
Some devices marketed specifically for TV use
Hearing aid users and non hearing aid users can use technologies

58. TELECOMMUNICATIONS: PHONES
Two needs with phones:
understanding conversation on the phone
knowing phone is ringing
There are two ways to understand the conversation on the phone: hear it or read it. There are four basic types of telephone amplifiers: portable, handset, inline and phone set.

59. TELECOMMUNICATIONS: PHONES
Types of telephone amplifiers:
Portable
Handset
Inline
phone set

60. TELECOMMUNICATIONS: PHONES
Portable amplifiers
Not recommended for regular use
Inconvenient--strapped onto a phone handset and need to be turned off after use or the battery runs dead
Occasionally helpful with wireless phones that do not have amplification
May make a phone hearing aid compatible
Peace of mind for use while traveling

61. TELECOMMUNICATIONS: PHONES
In-line amplifiers
devices that connect to the jack in the phone where the curly handset cord plugs in
may be a good value, as some go as high as 40 dB
Compatible with most phones, home and business.

62. TELECOMMUNICATIONS: PHONES
Amplification handsets
Replace original phone receiver
Less popular
Adjustment controls in the handle
In some cases, not electrically compatible
universal amplifier (battery or A/C powered) used for compatibility

63. TELECOMMUNICATIONS: PHONES
Amplified phones
Many features
Some provide 50 dB gain.
Louder not always helpful for clarity
Some provide tone control
Additional features (optional)
variable ringer sounds
built-in ringer light flash
big buttons for dialing
audio jack HAT
may require electrical outlet connection
cordless amplified phones

64. TELECOMMUNICATIONS: PHONES
TTYs do NOT use voice recognition
TTYs are data terminals that allow hard of hearing or deaf people to read typed messages
Some TTYs have a keyboard for typing a response
helpful to consumers who do not have clear speech
majority of hard of hearing prefer to voice their response.
Therefore styles of TTYs that are designed specifically to support VCO (voice carry over) may be appealing
One portable version is the size of a deck of cards and can be strapped onto most phone receivers.
TTY users communicating directly with another TTY or a relay service used to type spoken message to TTY user
VCO users find very appealing as they can read & talk and not worry about missing hearing message
With VCO, the TTY is then used for reading only.
With computer, it is possible to purchase software to emulate TTY signals

65. TELECOMMUNICATIONS: PHONES
Other telecommunications devices
pagers,
cellular phones,
fax machines,
and
Internet chatting, and
text-based intercoms
phone company custom calling helpful features
caller ID (for calling back the person through relay
distinctive ringing (for differentiating voice and TTY calls)
voice mail (to listen to voice messages with amplified phones or via the relay service)

69. Hearing Aids and You!

71. Cochlear Implants
Medel
Advance Bionics
Cochlear