A+
In general, mold modifications are as follows:
Venting affects lows, damping the midrange and horn effects boost highs.
Basic verification involves:
checking MCL and UCL in quiet and noise.
Sound field is
a controlled environment
The configuration and height of the tympanogram can be a factor in deciding the proper matrix for
the fitting of a hearing aid:
A high Type A tells us to decrease the output by 2-3 dB
You cannot use feedback checks when
checking the telephone coil
Verification procedures:
Check the accuracy of your fitting.
The problems produced by excessive ambient noise are
greater for the lower frequencies than the higher frequencies
The decibel is
a ratio between two intensities
REUR measurement are taken in
an open human ear canal
When a hearing aid is dead, you can check the receiver and microphone function by:
turning on the instrument telecoil
The dividing line between the external and middle ear is the
tympanic membrane
The cochlea, acting as a frequency analyzer, distributes acoustic stimuli to places along the basilar
membrane according to frequency. This forms the basis of a hypothesis called the:
Place Theory
An organic disorder is when there is damage to:
The hearing mechanism, the neural pathways and the brain.
,The speed of sound in air, in feet per second, is :
1100
Properly selected hearing instruments should allow:
The patient to wear an instrument at a comfortable loudness level, improved communication and
have better hearing aided.
Crystal microphones and receivers:
are very fragile
Which of the following is not a coupler used for measuring hearing aid performance?
Zwisks Ear Simulator
Small diameter tubing of SIA hearing aids has the effect of :
reducing the high frequency gain
The function of a microphone is to :
convert acoustic energy into electrical energy
Vent an earmold :
is the most common modification made on an earmold
When a new hearing instrument has feedback at the patients comfortable level, the problem is
usually:
too much wax in the ear canal
With SIE-S hearing aids:
The only signal is from the hearing aid and phrase effects from a vent are not an issue.
The most comfortable level is:
About 45 dB HL or 65 dB SPL for normal ears
Any complex sound can be broken down into individual frequencies by a technique known as:
Fourier Spectral analysis
The adult ear canal:
rises upward and forward, then descends to the drum.
An effective verification is:
a measure able improvement in communication
Which of the following is not included in correct test protocols?
plugging the hearing aid vent to control feedback
, Most conducive losses:
Are medically correctable, display a breakdown or obstruction in middle ear and display good
discrimination
The T position on a hearing aid switch can be used to
amplify a telephone conversation, couple hearing aid into a loop inductor, couple directly into the
audio of a radio or tv
The following components can change or modify the frequency response of a hearing instrument:
a microphone
Afferent fibers:
transmit from the cochlea to the brain.
User satisfaction must include:
patient preferences
The following measurements use SPL as a reference:
Probe microphones, sound field aided thresholds, and ANSI specifications
Speech discrimination tests:
approximate a sample of speech sounds in an ordinary conversation.
A formant is:
a frequency region within a complex tone where certain harmonics have relatively large energy.
Malingering is a category of :
non organic loss
Bone conduction threshold worse than air conduction thresholds may be caused by :
poor placement of vibrator, skull fracture, thickness of skull
Part of the basic law of electrical energy is :
protons attract electrons
Some patients with binaural amplification can experience:
degredation effect
The scala tympani is filled with:
perilymph
The following is a transducer:
electret microphone