Final Written Study Guide

Question 1

Explain the process of converting An analog electrical signal to a digital signal

Answer 1

Then sound goes to the analog to digital converter to go from an analog electric signal to a digital signal
ADC - when converting an analog signal to a digital signal the signal is sampled at discrete intervals (sampling rate)
Takes snapshots of the analog audio - must have 2 snapshots per wave cycle in order to accurately represent the frequency (one at the peak and one at the trough) - the higher the sample rate the more precise the recreation of the original audio is
The quality of the captured audio sample is determined by
sample rate - how many samples of the original signal are taken in periods of time
bit depth - determines the amount of possible amplitude values that can be recorded for each sample amplitude; The smaller the bit, the more noise you get; The greater the bit depth, the greater the detail in the audio
Quantization - each sampled value is rounded to the nearest value within a set of discrete levels and these levels are defined by the resolution of the ADC
Quantization error = noise floor
results in front-end distortion we see because for every bit is only 6 dB DR
16-bit digital word = DR of 96 dB
Digital signal now has numbers associated w/ it and moves to DSP

Question 2

Explain the process of converting
A digital signal back to electrical

Answer 2

converts amplified electric signal back to an acoustic signal
armature (flexible strip of metal balanced between two magnets like a diving board) is magnetized as the electrical current flows through the coil and it moves up in the positive direction towards that magnetic and down to the negative magnetic mimicking the electrical sine wave which is attached to the diaphragm above it and as the armature moves so does the diaphragm and this diaphragm movement causes the push and pull of the air creating an acoustic signal

Question 3

what is sampling rate

Answer 3

number of times per second an analog signal is sampled to create a digital signal - how we capture frequency information
Sampling rate takes regular snapshots of the continuous analog electric signal wave at evenly spaced moments in time & DSP only uses those snapshots (sampled points) and ignores everything else

Question 4

In order to capture the wave correctly how many shots for each cycle is needed

Answer 4

2
one at the highest point and one at the lowest point
If you do not get enough snapshots, the wave’s frequency will not be able to be accurately recognized

Question 5

what sampling rate do you want

Answer 5

high rate
more snapshots taken- the more accurate the original continuous wave is represented due to more sampling points

Question 6

what is the nyquist theorem

Answer 6

Nyquist rate is 2x the given frequency to be measured accurately
minimum sample rate for the highest frequency wanting to be measured

Question 7

what is bit depth

Answer 7

Measures the amplitude of the signal - horizontal measurement
Higher bit depth = more possible vertical amplitude values & more precisely the exact amplitude of a given sample can be recorded
It also means a wider dynamic range

Question 8

what is Quantization (Bit Resolution)

Answer 8

Depending on the bit depth, the exact amplitude value is rounded up or down to the nearest value using quantization
Higher quantization = more fluid sample
Lower = more choppy sample

Question 9

what is quantization error

Answer 9

The difference between the original acoustic signal and the transduced digital signal
Creates noise = noise floor

Question 10

Every bit only has —-dB of dynamic range

Answer 10

6

Question 11

16-bit digital word = DR of

Answer 11

96 dB

Question 12

Noise floor in the hearing aid is noise created in the circuit due to quantization error

Answer 12

TRUE

Question 13

waht is an algorith

Answer 13

Analytical calculations applied to the digital signal
They add, subtract or multiply strings of digital words
It creates a step by step set of decisions to achieve the desired result

Question 14

explain how algorithm works

Answer 14

ha is listening to environment and to the acoustic scene and deciding when combo of characteristics happen (spectral, temporal, amplitude) will automatically change programs and improvise the digitized signal processing to match any given listening environment

Question 15

Explain front end limitations associated with 16-bit processing, and how this impacts microphone sensitivities. How are these limitations resolved?

Answer 15

The smaller the bit, the more noise you get
The greater the bit depth, the greater the detail in the audio
16-bit processing has a dynamic range of 96 dB - it can collect sounds up to this but past this the sound becomes distorted
We get this dynamic range because each digital bit increase the front end dynamic range by 6dB
Solution: the dynamic range shifts by lifting the 96 dB higher to collect more sound sounds but it does this by sacrificing soft sounds

Question 16

what is an auditory filter, its function, effect of LF masking on a damaged cochlea and frequencies impacted by noise

Answer 16

Cochlea is a series of overlapping band pass filters (frequencies that are grouped together because they are close together on the cochela) that allow certain regions on it to stimulate to a specific frequency region while ignoring frequencies outside of the band
The filters have a lot of overlap with each other so HF bands pick up LF signals from adjacent critical bands and as a result, noise can mask signals from adjacent critical bands
In normal hearing, sharp tuning curves allow for precise frequency discrimination & perception of sounds
w/ HL, the curve is broader and noise can easily affect perception of the desired signal
Broadening of the filters is mainly on the LF side, leading to the increasing of LF masking. So the LF noise masks the region it normally would but also spills over to the overlapping HF bands around it making it more difficult for the PT to use the cues to understand the speech over the noise

Question 17

how many bands are in the as

Answer 17

25 bands
LF bandwidths are narrow - only 160 Hz wide
HF bandwidths are wide- up to 2500 hz

Question 18

what is upward spread of masking

Answer 18

Intense 250 hz LF noise will mask that frequency region but the masking will also spill over to the overlapping HF critical bands
Noise energy peaks around 250 Hz but upward spread of masking impacts audibility up to about 1500 Hz

Question 19

Types of Noise that Impact Intelligibility

Answer 19

Steady state signals
Random noise with an intensity frequency spectrum like speech (speech like sounds)
10-talker babble
4 talker babble
2 talker babble
Which is harder to hear in?
Room reverberation

Question 20

what are the methods of sound cleaning technology

Answer 20

spatial domain
temporal domain
spectral

Question 21

Differentiate modulation rate and depth for speech and noise.

Answer 21

Speech & noise signals have time differences
Modulation rates
Speed of the signal
Speech = slow rate
Noise = fast rate
Modulation depth
Amplitude variations bw loudest and softest portions of the signal
Intensity of the variations
Speech = highly variable
Noise = steady over time

Question 22

How is poor SNR determined in a hearing aid?

Answer 22

it looks at the mod rate and depth
for noise, mod rate is slow and mod depth is steady over time so it takes this and eliminates it from the signal

Question 23

how does digital noise reduction work

Answer 23

Steady state noise
Idling engine, hair dryer, vacuum etc.
Only acts on fast mod rates & low mod depths
Varying degrees can be applied to each frequency range
doesn’t improve speech intelligibility
Can improve listening comfort, reduce listening effort, reduce cognitive load

Question 24

does DNR improve speech intelligibility

Answer 24

no
doesn’t improve speech intelligibility
Can improve listening comfort, reduce listening effort, reduce cognitive load

Question 25

Methods of sound cleaning technology used in the spectral domain

Answer 25

HA here looks at a signal’s frequency to control the signal Theory is that If noise is below 1.5 and then understanding speech comes from mid and high frequencies reducing the output in low frequencies will improve speech intelligibility in noise if we attenuate and reduce lf amp and leave in hf, then we will probably improve speech intelligibility issue: there is noise still in HF not just all in the LF

Question 26

Methods of sound cleaning technology used in the spatial domain

Answer 26

noise here is managed by directional mic technology by turning in the direction of the signal the ha provides spacial separation from the speech and noise adaptive vs fixed beamforming

Question 27

superior when only a few noise sources are present

Answer 27

adaptive

Question 28

superior in the presence of multiple noise sources

Answer 28

fixed

Question 29

what is automatic mic switching

Answer 29

ha automatically listen to seen and when they think there is enough noise in the room, switch from omnidirectional to directional Will switch to a fixed direction (one polar plot) or an adaptive directional mic (multiple polar plots)

Question 30

purpose of automatic mic switching

Answer 30

Switching occurs automatically and continuously Microphones revert to omni-directional mode in quiet Feature has an override switch Polar plots allow reverse directionality to supply a side or backwards zoom sometimes you want to hear what is behind you and not what is in front driving in the car sitting with group in class or in movie theatre and friends are behind you

Question 31

what is adaptive directional mic

Answer 31

turns directional mics on and off when needed Directionality of a mic sensitivity is determined by external and internal time delay Here time delay is digitally manipulated to shift the azimuth of a null based on sounds location Automatically changes the null as locations of undesired signals moves behind the listener - null steering Can steer across a BB frequency range or in narrower frequency ranges

Question 32

what are broadband and multiband mics

Answer 32

Broadband and multiband mics varies null point for different frequency ranges (bunch of polar plots stacked on top of each other

Question 33

what is beamforming

Answer 33

Has a very narrow beamwidth (only azimuths of + 25°, + 35°, + 50° Monitors overall intensity of environment When signal is <55 SPL widest beamwidth activates As environmental intensity increases (>75 SPL) smallest beamwidth is activated

Question 34

ONLY thing we can do in digital ha tech to improve speech intelligibility is to

Answer 34

enable directional mics

Question 35

Explain Weiner filter function and limitations

Answer 35

Spectral subtraction approach, measures short term noise spectrum during gaps in speech Improves acceptance of background noise but doesn’t improve intelligibility Worlds good on steady noise but not fluctuating so it is not effective in real time noisy situations Reads between the lines in desired signal and takes out background noise found in the modulations of speech

Question 36

what are 3 methods to reduce external feedback

Answer 36

Reduce external feedback loop Digital notch filtering Digital feedback cancellation

Question 37

explain Reduce external feedback loop

Answer 37

Increase snugness of mold to reduce size of slit leaks Or decrease vent size to stop feedback path Limitation: both increases OE

Question 38

explain digital notch filtering

Answer 38

Removes frequencies around the noise - reduces gain around 2-4 kHz where feedback occurs HA between this range with notch creates a notch in frequency response so we don't amplify sound in those regions - reduction in gain from 2-4 kHz and if you don't turn the volume up it won't cause feedback Limitation 35% of intelligibility comes from this range alone so you stop feedback but stopped audibility of important speech sounds so reduced speech intelligibility

Question 39

explain digital feedback cancellation

Answer 39

When HA detects feedback (identified due to steady state noise bw 2-4 kHz) an algorithm creates an out of phase clone of the signal (duplicate of the feedback) and this causes the clone to be subtracted from the amp path and in turn attenuates the feedback

Question 40

Describe the limitations of each feedback reduction method (DFS)

Answer 40

Algorithms can cause brief feedback until the out of phase tone can activate Any sustained tone can start an algorithm (whistle, violin, etc.) Audible beep when an external signal is mistaken for feedback - entrainment Feedback cancellation can distort or attenuate parts of speech Faster battery drainage and life

Question 40

what are the 3 types of frequency lower

Answer 40

linear frequency transposition nonlinear frequency compression spectral envelope warping

Question 41

what is frequency lowering

Answer 41

Only works from high to low Best for steeply sloping HF HL tries to improve HF audibility by shifting it down to LF

Question 42

do we turn FL on for adults initially

Answer 42

measure signal audibility, turn feature on later use auditory closure skills so it is less imperative we turn it on

Question 43

do we turn frequency lowering on for children initially

Answer 43

they are learning language and audibility of s and z is important for them, as soon as it is identified it is turned on

Question 44

explain linear frequency transpostion

Answer 44

CUT AND PASTE into LF, takes the highs and shoves it into the lows Improves HF audibility by moving HF band one octave down to LF region

Question 45

explain nonlinear frequency compression

Answer 45

piano keys HF range is compressed into a LF range; squishes it down into the audible region maintain tonotopic order more, lowered all the frequencies, squished into lower frequency space, close to each frequencies close to their original spot

Question 46

explain spectral envelope warping

Answer 46

Leave the HF where it is but also COPY and PASTE into LF Keeping a portion in HF but also transposing portion down to LF range *oticon colors

Question 47

how does digital wind noise reduction work

Answer 47

Wind turbulence only affects one diaphragm so the HA talk to each ither and take the signal on the opposite side and transmit it and overlay it so it seems like the noise went away and improves snr in that environment LF filtering can be applied - energy of wind is around 300 hz

Question 48

Describe the uses and benefits associated with wireless binaural processing technology

Answer 48

HA’s talk to each other Wind noise management - how does this work Dual phone - ha streams call into opposite ear to get binaural herring Volume control Program

Question 49

how does binaural help with ILD How does it support improved awareness of ILD in HA’s

Answer 49

As it arrives to second ear it is lower and wdr adds more gain on that same side so the ILD are gone so you cannot hear well in noise so binaural wireless the one ha tells that ha to not add as much wdrc One ear will tell the other ear to not add as much wdrc so it doesn’t lose ILD

Question 50

what is digital data logging

Answer 50

Helps with counseling topics & ways to customize them to meet their lifestyle needs

Question 51

Which is better for high noise environments? fixed or adaptive? why?

Answer 51

Fixed is better for more noises because it attenuates all the signals Adaptive is better for a few noise sources because it is not smart enough to determine which ones to attenuate; it doesn’t know how to function

Question 52

The more BB the noise the greater the effect on speech works on steady state noise, improves listening effort, working memory, reduces cognitive load but doesn’t improve speech intelligibility Can improve listening comfort, reduce listening effort, reduce cognitive load

Answer 52

digital noise reduction (temp domain)

Question 53

Most noise is <1500 Hz, if we reduce output here it will reduce background noise but it assumes all competing signals are in the LFs and this is not true Background noise is in HF too

Answer 53

spectral domain

Question 54

what is the test box for

Answer 54

Acoustic chamber Reduces reflections Low ambient room noise Calibrated sound sourccw

Question 55

what are the speakers for

Answer 55

Emit measurement signal

Question 56

what is the refrence mic

Answer 56

Calibrates SPL output from speakers

Question 57

waht is the coupler mic

Answer 57

Measurement mic collecting output from the HA

Question 58

Simulates size of the canal Custom products - ITE & ITC Uses fun tak to attach HA to it

Answer 58

ha 1

Question 59

Traditional BTE w/ earhook Attach directly to hook

Answer 59

ha 2

Question 60

Only for verifit 2 Used for CIC, IIC, RIC Smaller cavity volume mimics the deeper placement of the device Realistic picture of frequency response in >HFs

Answer 60

.4cc

Question 61

what is the zwislocki coupler

Answer 61

Better simulates characteristics of the ear canal Avg canal has HF SPL that is higher than the LF SPL

Question 62

OSPL 90- Output SPL @ 90 dB

Answer 62

This shows output for a 90dB SPL input signal (MPO) Loudest possible output point device can produce for a 90 dB input signal & represents a single frequency

Question 63

HFA OSPL 90- HF Avg output SPL @ 90dB

Answer 63

Calculates the average OSPL 90 output for 1, 1.6 and 2.5 kHz *3 triangles at the bottom

Question 64

HFA FOG - HF avg full-on gain

Answer 64

Shows avg gain for 1, 1.6, 2.5 for a 50 dB signal Estimates the max gain available at different frequencies when an avg input signal is amplified

Question 65

Equivalent Input Noise (EIN)

Answer 65

Measures the internal noise of the HA Typically 25- 30 dB SPL is acceptable

Question 66

Should be below 5-10% High DL are indicators the device is close to failing (most likely the receiver) & needs sent in for a repair

Answer 66

% THD

Question 67

Compares output of an input signal coming from 0-deg azimuth to the input signal coming from 180-deg azimuth

Answer 67

directional mic front to back ratio

Question 68

Larger differences (FBRs) suggests a greater directivity index is achieved to improve SNR & speech understanding in noise

Answer 68

yes

Question 69

Degree of attenuation is dependent on amount of modulation in the signal and intensity of the signal

Answer 69

digital noise reduction

Question 70

what signal is emitted form TMTF T in box

Answer 70

electromagnetic

Question 71

SPLITS

Answer 71

output response of telecoil (horizontal = phone)

Question 72

telecoil output it louder than the mic output

Answer 72

+ RSETS

Question 73

vtelecoil ouput is softer than the mic output

Answer 73

- RSETS

Question 74

SPLIV

Answer 74

SPL in a vertical magnetic field Looped environment

Question 75

SPLIV - output of telecoil RTLS - difference bw mic and telecoil

Answer 75

true

Question 76

first limitation to frequency response of HA

Answer 76

sampling rate

Question 77

how does input stage impacts the final frequency response (bandwidth) and output of the device

Answer 77

mic can collect wide frequency response from environment but as signal transduces through HA the range and output changes so that final output and frequency response are dependent on

Question 78

how does processing stage variables impacts the final frequency response (bandwidth) and output of the device

Answer 78

dynamic range of mic is impacted by bit rate of adc converter

Question 79

how does output stage variables impacts the final frequency response (bandwidth) and output of the device

Answer 79

Receiver size & design Acoustic parameters - sound bore (earhook, tube length & shape Signal changes as it travels through the sound bore Standing waves can cancel the signal & the shape of the sound bore can increase or decrease HF output

Question 80

purpose of a receiver

Answer 80

converts amplified electric signal back to an acoustic signal

Question 81

how does a receiver work

Answer 81

armature (flexible strip of metal balanced between two magnets like a diving board) is magnetized as the electrical current flows through the coil and it moves up in the positive direction towards that magnetic and down to the negative magnetic mimicking the electrical sine wave which is attached to the diaphragm above it and as the armature moves so does the diaphragm and this diaphragm movement causes the push and pull of the air creating an acoustic signal

Question 82

Receiver sizes determine the final HF output \

Answer 82

true

Question 83

HF signals need _____ diaphragm movements

Answer 83

rapid

Question 84

Smaller contemporary receivers are capable of _____ frequency responses

Answer 84

highr

Question 85

what is the problem with large receivers for severe losses

Answer 85

limit output bandwidth (frequency response) HF are lost due to increase armature flexibility

Question 86

what is the solution tothe loss of hf with larger receivers

Answer 86

two receiver system (dual receivers?) Output from both receivers added together when it reaches the ™ One is for LF One is for HF

Question 87

what is the benefit of two receiver system for severe losses

Answer 87

reduces battery drain, gives a good EHF output w/out compromising a lot in LF and minimizes saturation distortion potential

Question 88

what is receiver saturaton

Answer 88

This happens when the receiver output is reached resulting in peak clipping or the receiver having a higher voltage and battery drain HA output range has been exceeded leading to distortion due to peak clipping

Question 89

what is shock damage

Answer 89

Caused by a dislodged receiver where the vibration goes back into the mic adding extra frequencies to the input signal leading to distortion

Question 90

how does cerumen/moisture debris affect receivers

Answer 90

break because of moisture, debris, oil, gets into it and clogs it up Can block the receiver diaphragm and cause reduced output of the receiver

Question 91

what is the soundbore path

Answer 91

A column of air that sound waves pass through leaving a receiver that arrives to the ™ Final output & bandwidth (frequency response) of device changes based on a sound bore paths acoustic parameters/physical properties

Question 92

Do ric devices have a sound bore?

Answer 92

no

Question 93

what happens in sound bore flaring

Answer 93

HF output is changed based on the side of the flare Increases HF depending on length and size of the flare

Question 94

what happens to frequency range with thin tube

Answer 94

Making the tube thinner decrease the HF output & shifts the peak resonance down to lower frequencies (1000 hz down to 800)

Question 95

Describe the impact of standing waves within the soundbore on the final output signal

Answer 95

This happens when reflection in the sound bore causes the wave to overlap with itself This causes two waves of the same frequency to either be in phase creating a single sound that is louder or two identical waves 180 deg out of phase and cancel each other out

Question 96

Thin tube in standing waves changes HF response. How

Answer 96

Smaller internal diameters of a thin tube cause reduction in HA HFO & shifts tube resonance down to around 800 Hz

Question 97

how does libby horn change output and frequency response

Answer 97

nternal horn shape increases HFO

Question 98

what needs to happen for libby horn to increase HFO

Answer 98

internal diameter over a specific length needs to be increased gradually issue: benefit depends on maintaining length of flare canal cannot just be a flare has to have a certain length cannot always get diameter or length to fit into individual horn

Question 99

Depth of soundbore in canal

Answer 99

Increased length = Increased SPL for ALL frequencies

Question 100

what is the purpose of a damper

Answer 100

Acoustic resistor Physical barrier to reduce sound Smooths the resonances in the final frequency response Does so by attenuating sounds slightly to smooth the peaks

Question 101

what is a limitation of dampers

Answer 101

Sound waves lose energy as they travel through the damped material

Question 102

Amount of acoustic resistance applied to the resonance

Answer 102

ohm

Question 103

Higher ohm = less resistance

Answer 103

false more

Question 104

what are the stages of pressure sores

Answer 104

Stage 1: redness, not swollen, can identify red spot Stage 2: swelling, but not too much and redness Stage 3: pressure sore that starts to fill with fluid, skin isn’t broken but swollen and raised, blister Stage 4: skin breaks, can’t wear HA until it heals, open wound that needs managed

Question 105

Course Used to modify silicone Need to use at least 25k to 20k RPM for best results

Answer 105

blue stone

Question 106

For grinding acrylic or vinyl Smaller one is for smaller areas

Answer 106

white stone

Question 107

Removes large amounts of material fast

Answer 107

low grit

Question 108

Removes less material and smoother finish

Answer 108

medium grit

Question 109

Smooths and restores shine Only used w/ lucite/acrylic molds

Answer 109

fine grit

Question 110

Final edge smoothing

Answer 110

nail file

Question 111

Review factors which may reduce battery life (environmental, and patterns of use)

Answer 111

Ear to Ear wireless transmission FM signal processing Tinnitus Masking Programs Bluetooth streaming features Low battery warnings

Question 112

chemical dry out Shelf life 2-3 years, maintains voltage for about 6 weeks. Maintains stable 1.25Vm deteriorates rapidly at the end

Answer 112

zinc air

Question 113

used to be common, recharge time 6 hours, life 10 hours (less than zinc air). Capacity fades over lifetime, manufacturer replacement about once a year. Cost comparable to disposables over the lifetime of the aid

Answer 113

nickel metal hydride

Question 114

discontinued in 2020, 7 hour recharge, lasts for at least a day. Voltage runs higher than other batteries, needed voltage regulators to be installed before use

Answer 114

silver zinc agzn

Question 115

Offered by all major manufacturers Energy efficient, long life, fast charging – 30 mins = 6-7 hour life, lasts the life of the hearing aid Disadvantages- faulty chargers are a huge pain, no replacement if battery loses its charge, must be replaced every 3-4 years.

Answer 115

lithium ion batteries (R)

Question 116

what are pros for rechargeable

Answer 116

Convenience No small batteries No keeping track of batteries More eco friendly No buying batteries

Question 117

what are pros of disposable

Answer 117

Convenience Smaller HA size Lower HA cost Better reliability

Question 118

what goes in s of soap note

Answer 118

Things you learn through talking w/ the patient and others Must have reason that supports each diagnostic exam

Question 119

what goes in o of soap note

Answer 119

documents your diagnostic test results Describe specific findings from things you glean from observing, touching, testing Otoscopy was normal, normal tymps, normal reflexes, normal OAeS

Question 120

what goes in a of soap note

Answer 120

eviews what you think is causing the issue? Interpretation statement based on your professional knowledge describing the relationship b/w subjective and objective findings Theoretical analysis of the underlying cause based on the relationship b/w the subjective/objective findings A clear statement of your interpretation of the findings as it relates to the symptoms considering normal audiometric studies, it appears PT symptoms are result of occupational ____

Question 121

what goes in p of soap note

Answer 121

management recommendations based on findings What should the patient do next? Describe recommendation of the next steps to take

Question 122

Mrs. Hicks is a candidate for audiologic rehabilitation which may include bilateral amplification, auditory training, and group aural rehabilitation. It is recommended that she return to my office to complete a communication needs assessment.

Answer 122

plan

Question 123

Frances Hicks, a 95-year-old female reports difficulty communicating, especially when in noisy environments. The patient denies symptoms of aural fullness, discomfort, tinnitus or balance concerns. A review of systems finds no other medical concerns.

Answer 123

subjective

Question 124

Assessment results reveal Mrs. Hicks threshold loss is causing communication difficulties. Findings suggest loss of haircell function in the cochlea. There is no evidence of middle ear or retrocochlear pathology

Answer 124

assessment

Question 125

Diagnostic studies reveal mild to moderate sensori-neural hearing loss bilaterally; tympanometric results show normal ear canal volume, peak pressure and static compliance in both ears; acoustic reflex thresholds were present ipsilaterally and contralaterally at reduced sensation levels, distortion product otoacoustic emissions were absent bilaterally.

Answer 125

objective

Question 126

SBAR communication method to relay a call for action to another healthcare provider

Answer 126

Get to the point asap Situation: brief statement of the problem you are facing Background: follow up with pertinent case details Assessment: statement of concern Recommendation/request: what are you asking of them

Question 127

Define patient centered care (PCC)

Answer 127

Active involvement from PTs and their families to design new care models in decision making about their options for treatment Takes time & dont get reimbursed but we can for other services - need to bill & code effectively to be reimbursed for services we do provide

Question 128

Define fiduciary as it relates to the PCC-based treatment plans audiologists recommend

Answer 128

Trust a person places trust, confidence, and reliance on another to exercise discretion or expertise in acting on behalf of the client.

Question 129

what is a cpt 4

Answer 129

describes diagnostic procedure

Question 130

what is HCPCS

Answer 130

coes describing services & supplies

Question 131

what are ICD 10

Answer 131

codes classifying diagnosis and/or symptoms

Question 132

what are medical necessity

Answer 132

These are services that are provided for the diagnosis, treatment, cure, or relief of a health condition, illness, injury, or disease

Question 133

Describe Medicare’s physician order requirements

Answer 133

Required for services in all settings except tests for non-acute hearing conditions Once every 12 months

Question 134

when will medicare reimburse

Answer 134

eval of cause of hearing tinnitus balance disorders eval of change in hearing tinnitus or balance finding how medicaiton, surgery or other effects PT failure of screening test

Question 135

when will medicare not reimburse

Answer 135

When the auditory/balance status is already known When the reason for the hearing assessment is unrelated to hearing aids, or examinations for the purpose of prescribing, fitting, or modifying hearing aids

Question 136

Understand how a carbon microphone works. Specifically, how it converts an acoustic signal to an electrical signal

Answer 136

sound waves come, hit diaphragm and compress it when it moved in, the carbon balls are pushed together creating pos voltage flow, sound waves go back and forth so when it goes back so does the diaphragm so the balls decompress compression and decompression of carbon creates a + and - electrical current sound has positive peaks and negative these hit d, compress/decompress the carbon balls, and because it created the +/- current flow, the electrical current matched the acoustic sign wave input signal is blue and comes in it changed and what came out looks the same but it wasn’t sound transferred acoustic signal to electric signal that looked identical it is an analog electric signal analog - the same, shape of signal that came out of the microphone is exactly the same as shape of signal that went into the microphone now we have electric imitation of sound we can use it to do stuff but we do not have an amplifier yet

Question 137

Define temporal resolution

Answer 137

The ability of the auditory system to detect time related changes in the acoustic stimuli over time Needed in order to understand speech in noise Ex: shutter speed = temporal resolution If it is not fast enough the speech will be blurred or smeared like a photo In a noisy environment it is hard to pick out what individual words are Time related Cues

Question 138

explain 3 processes that support temporal resolution

Answer 138

Gap detection brief gaps of pauses between syllables, words, sentences, etc Phonemic duration some words are elongated, shortened etc. - distinguishes one word from another can vs cant Temporal ordering (boots; boost) Time related aspects of acoustic signal boots vs boost Suprasegmentals Provides us with meaning (is it a question, a demand, etc.) Patterns of stress Intonation rhythm

Question 139

Explain binaural loudness summation. Its suprathreshold benefits and how this benefit supports hearing aid fitting strategies.

Answer 139

The auditory system increases the perception of loudness when auditory input signals are received from two ears Increases threshold around 2-3 dB & increase suprathreshold around 6-8 dB Results in PT perceiving greater loudness w/ bilateral devices Less gain is needed to reach comfortable listening levels Can fit a PT with less loudness in order for them to hear the words

Question 140

What does a 6/8 IP rating suggest?

Answer 140

Dust light Protects against long periods of liquid immersion

Question 141

How easily the material flows before it cures; thickness

Answer 141

viscosity

Question 142

Materials ability to return to shape after removal

Answer 142

stress relaxation

Question 143

Shrinkage over 7 day period

Answer 143

contraction ratio

Question 144

After cure hardness

Answer 144

shore value

Question 145

Describe the cause of the occlusion effect (OE) and associated patient complaints. Describe the degree of LF threshold loss associated with OE concerns Describe two management techniques used to reduce OE

Answer 145

Increased perception of one’s own voice when something is blocking the ear canal Common complaint occurs when LF threshold is better than 50 dB Causes Dome closes off the ear Mold with too small of a vent Insufficient venting and/or insufficient canal length non custom couplers result in less complaints of OE Vent size & stabalizing the device in the bony canal are two management techniques to reduce OE Move past cartilage to bony portion stopping vibrations & vent allows more energy to flow through

Question 146

Describe the impact vent size has on high frequency output

Answer 146

Vent size impacts HF output The larger the vent the less HF output you get from a HA

Question 147

Define front-end distortion and its cause. Describe why digital HA’s have a lower mic dynamic range. Describe how front-end distortion is managed in digital hearing aids.

Answer 147

*mic has a dynamic range and FED happens when the input signal exceeds this Distortion in analog - input >/= 115 dB SPL (anything louder sounds distorted) Distortion in digital mic happens with input >/= 96 dB SPL (0-96, anything louder sounds distorted)

Question 148

Real world snr is 2-3 because of head shadow and polar plots If Signal was 76 and noise 74 what is SNR?

Answer 148

2 dB

Question 149

Greatest directivity index

Answer 149

hypercartiod

Question 150

Explain how raising/lowering TK input alters output of signals at or below the TK. Describe practical applications for this adjustment (include adjustments for high and low TKs)

Answer 150

lowering the TK to a softer input intensity will not change the output of the louder input signals raising the TK to a loader input signal decreases the output of signals below the TK lowering the TK to a softer input intensity increases the output of signals below the TK Practically, shift TK down if a PT needs more clarity of soft consonant sounds & shift TK up to reduce audibility of soft low frequency background noise

Question 151

Explain expansion & its purpose. List CR associated with it

Answer 151

ower output with very very soft sounds as input increases amount of gain applied is reduced = compression as input increases amount of gain applied is rapidly increasing too = expansion Very soft acoustic signals below the first threshold kneepoint (TK) are attenuated by applying Expansion <.9:1 CR