oto hearing aids and implantable hearing devices Flashcards
What are assistive listening devices?
Auditory and nonauditory technologies that overcome
limitations associated with the physical distance between
the sound source and the patient
Provide examples of auditory and nonauditory
assistive listening devices.
● Auditory: Microphone systems that capture the desired
sound next to the sound source and transport the signal
to the listener using FM, infrared, induction loop, Blue-
tooth, or hard-wired systems
● Nonauditory: Alarm systems using vibrotactlile or visual
signals to alert the patient of an event such as a phone
ringing or doorbell activation
What conservative measures should be discussed
with patients who have hearing impairment?
Strategic seating at meetings or events (better ear toward
speaker, sitting close to the front), making eye contact with
speakers, reducing competing background noise
Describe the basic components of a hearing aid.
Microphone, amplifier, receiver, power supply
Define gain as it pertains to conventional hearing
aids.
Gain is the difference between the level of input and level of
output at any given frequency.
What advantages do vented hearing aids provide?
Decrease in external auditory canal moisture, decrease in occlusion effect, dissipation of low frequency input (advantageous in patients with primarily high-frequency hearing loss).
What factors should be considered in predicting
patient satisfaction with traditional hearing aids?
The best candidates are motivated patients who are
receptive to the idea of hearing aid use. Those with
predominantly high-frequency hearing loss generally do
better than those with low-frequency hearing loss. Severe
to profound hearing loss is often difficult to aid. Supra-
threshold speech and speech recognition performance is
important; patients with good word recognition when
amplification is provided are more likely to report satisfac-
tion and continued device use.
Describe the difference between the speech
reception threshold and the speech discrimination
score.
Speech reception threshold is the quietest volume (in dB) at
which presented spondaic words can be identified at least
50% of the time, whereas the speech discrimination score is
the percentage of time that a presented word is correctly
identified.
Describe the advantages and disadvantages of the completely-in-canal and the in-the-canal hearing
aid.
● Advantages: Discreet size offering enhanced cosmesis;
takes advantage of the ear’s innate shape assisting with
natural sound amplification and limiting undesirable wind
noise
● Disadvantages: Power limitations, cerumen clogging,
aural fullness and occlusion effect, difficult fit, fine
dexterity requirements, cost, and external ear canal
irritation
Describe the advantages and disadvantages of the in-the-ear hearing aid.
● Advantages: Delivers adequate power to rehabilitate mild
to moderately severe losses, more powerful, and easier to
manipulate than in-the-canal models
● Disadvantages: Require some manual dexterity for place-
ment and volume control. Less discreet than in-the-canal
models
Describe the advantages and disadvantages of the behind-the-ear hearing aid.
● Advantages: Most adaptable hearing aid option; delivers
enough power to rehabilitate moderately severe to severe hearing loss; generally offers more signal processing features; and is easier to handle than smaller
devices in patients with poor manual dexterity
● Disadvantages: Larger size, less discreet, pinna irritation
What is the primary advantage of a body aid?
With severe-to-profound hearing loss, feedback problems
occur with ear-level devices because of the close proximity
of the microphone to the receiver. The body aid places the
microphone at a distant site from the amplifier, typically on
a belt or in a pocket.
With regard to hearing aid technologies, what are
the primary advantages of digital processing
compared with analogue processing?
Beyond affording multiple programs, digital signal processors can selectively amplify specified frequencies, reduce acoustic feedback and background noise, automatically
detect changes in listening environments to dynamically
optimize signal, and offer enhanced connectivity to external
sound sources.
What are directional microphones, and what advantages do they have over standard omnidirectional technologies?
Directional microphones selectively amplify sounds located
in front of the listener, improving the signal-to-noise ratio.
Adaptive directional microphones go one step further and
are able to vary the direction of maximal amplification.
Describe the utility of a CROS and BiCROS aid.
The CROS (contralateral routing of signal) aid takes sound
from the poorer ear and relays the signal to the better,
contralateral ear. The BiCROS (bilateral contralateral routing
of signal) aid similarly “throws” sound to the good ear but
also amplifies sound in the receiving ear.
