Chapter 14: Amplification/Sensory Systems

Question 1

Hearing Aid Development

Answer 1

-First sound collectors were horns and seashells that funneled sounds into the ear canal
-First electronic hearing aids limited user to the proximity of a table that supported the device

Question 2

Analog Hearing Aids

Answer 2

-Create electronic signals that are analogous to the sound coming into the instrument
-Modify a continuous electronic signal

Question 3

Digital Hearing Aids

Answer 3

-Convert sound waves into numbers that are stored as binary digits

Question 4

Today’s Digital Hearing Aids

Answer 4

-Provide a high speed manipulation of signals for enhanced processing
-Provide improved clarity of signals and improved signal-to-noise ratios
-Can to some degree, filter out unwanted signals
-Can store different listening conditions

Question 5

Compression Circuits

Answer 5

-Work to reduce loud sounds and keep these sounds within the patient’s dynamic range

Question 6

Directional Microphones

Answer 6

Suppress sounds from a set direction to help enhance the signal to noise ratio of the desired signal

Question 7

Telecoils

Answer 7

-Electromagnetic coils that when activated allow sound to bypass the hearing aid’s microphone to allow the patient to hear select signals more clearly

Question 8

Behind the ear hearing aids (BTE)

Answer 8

-suitable for mild to moderate hearing loss
-can be fit with customs earmolds
-routinely used with children because the earmolds are easy to replace as their ears grow

Question 9

Receiver in the canal hearing aids (RIC)

Answer 9

-much smaller than behind the ear
-chance of acoustic feedback increases with greater loss

Question 10

In the ear hearing aids (ITE)

Answer 10

-Hearing aid sits in the concha and external auditory canal with circuitry built directly into the earmold
-Suitable for mild to severe losses

Question 11

In the canal hearing aids (ITC)

Answer 11

-limited in power due to the size of the aids
-may be suitable for mild to severe losses with modern feedback suppression circuits

Question 12

Completely in the canal hearing aids (CIC)

Answer 12

-recessed within the external auditory canal
-often the cosmetic advantages are not as great as the receiver in canal aids
-smaller batteries reduce ability to couple to cell phones and other assistive listening devices

Question 13

Invisible in the canal hearing aids (IICs)

Answer 13

-Smallest style that can only be fit if the patient’s ear canal is large enough to accommodate the device electronics
-Same advantages and disadvantages as C I C s

Question 14

Binaural Amplification

Answer 14

-Most patients are fitted with two hearing aids but it doesn’t automatically mean a true binaural processing of sound

Question 15

Contralateral Routing of Offside Signal (CROS)

Answer 15

-used for patient’s with an unaidable hearing loss in one ear
-sounds from bad ear are sent to and amplified in the good ear
-canal of the normal hearing ear is left as unoccluded as possible to allow unaided sounds to travel through normal sound transmission

Question 16

BiCROS Hearing Aid

Answer 16

-Works in the same way as a CROS system except the “better” ear has an aidable hearing loss

Question 17

Limitations to CROS and BiCROS Systems

Answer 17

-As all signals are being delivered to only one ear difficulties adequately hearing speech in noise may remain and sound localization is not restored

Question 18

Bone Conduction Hearing Aids

Answer 18

-Used for patients with conductive hearing losses and otological conditions that prevent the use of air-conduction amplification systems
-True binauaral hearing is not possible

Question 19

Implantable Hearing Devices

Answer 19

-Used when nonsurgical options do not provide benefit for the type or degree of hearing loss that a patient has

Question 20

Hearing Assistive Technologies (HATs) or Assistive Listening Devices (ALDs)

Answer 20

-Signaling or alerting units such as flashing lights, vibrations, or increased sound intensity
-Include telephone ringers, remote doorbells ringers, amplified or vibratory alarm clocks, smoke detectors with lower-frequency amplified alarm, amplified and/or captioned telephones, remote clip-on microphones, and others