HA EXAM 2

for Loudness summation there is a ___dB at threshold, ___dB at 50dBHL, ____dB at 90dBHL

+3; +6; +9

what is the programability benefit

- adjustments easier to make -electrical programmability allowed for more adjustments to be made

what are the 3 peak clipping methods that were created

-asymmetrical "hard peak clipping" -symmetrical (a little less distortion) -soft peak clipping "peak rounding"

when audibility of HF may not be helpful what 3 things could happen

-cannot deliver HF gain without FB issues -HL is too severe in this range to provide audibility -cochlear dead regions

what are the 3 things related to static compression

-compression ratio -compression threshold -compression range

what is wide dynamic range compression

-compression starts at lower input level -less compression but over a wider range Low knee point Low compression ratio

the 3 disadvantages of DSP (potential)

-dispenser education -time spent programming and reprogramming -cost to patient

when compression is adjusted by means of changing the software what does this mean

-essentially change hardware chip -impacts algorithm of instrument

what are the fig 6 three input levels calculated

-gain for < 40 dB inputs -gain for 65 dB SPL (conversational speech) -gain for 95 dB inputs

what do HA schemes provide (4 things)

-gain reduction for noise -gain enhancement for speech -activation time -SNR and level effects

individual features of DSP aid

-multiple channels -multiple memories -noise reduction -frequency lowering -data learning

what 4 things should we consider when it comes patients and multiple programs

-must consider the person and lifestyle -what are their typical listening situations -can they handle the complexity -can the access the programs (remotes, apps?)

what were the predicted MCLs in Fig 6 done by Pascoe

-normal hearing: mean MCL 65 dB HL -mild loss- 77 dB HL -moderate loss- 90 dB HL -as HL was greater, mean MCL increased

what are the two main things with analog compression

-output compression -input compression

what happens when there is less redundancy for speech for individuals with hearing loss (2 things)

-part of the speech isn't audible -speech may be distorted

who are the best candidates for frequency lowering

-patients who experience speech perception deficits due to insufficient HF audibility in terms of level (an bandwidth) -children or adults? -adults can take advantage of linguistic knowledge, better auditory closure

7 things associated with signal complexity

-precise control over stimulus parameters -feedback management -noise management -multiple microphones -loudness compensation -reduction of instrument noise -simplicity of fitting

conversion involves what two fundamental steps

-sampling -quantization

how do we restore normal loudness growth (how do we manage this)

-soft sounds should continue to be perceived as soft -moderate sounds comfortable -loud sounds loud but tolerable (compression)

what two names does impulse noise reduction have

-sound smoothing -sound relax

what are the 3 frequency lowering terms

-source region -starts frequency -target region

what are the 4 other important factors of the DSP aid

-timing devices/clocks -algorithms -memory -closed versus open platforms

what was the bisection theory

-wallenfels proposed it in 1967 -you choose frequency and gain characteristics for the patient -region between HL and LDL is divided in half from 1k-4k Hz GOAL: maximize speech intelligibility

what are the two most important types of compression

-wide-dynamic range -compression limiting

omnidirectional microphone FBR=

0 (no difference)

Omnidirectional DI

0 dB

Omnidirectional mic AI-DI

0.3dB

What is the Articulation Index (AI) based on this audiogram?

0/100 so 0%

100 dB/100 dB =

1 1:1 needed for a normal hearing person

1 MHz clock stands for and clocks operate in

1 million cycles per second -hundreds of thousands of instruments can be carried out each second -gigaHz range

How are T-rating and M-ratings scaled?

1-4 (4 being the best)

what are the two ways we manage loudness

1. -MPO- maximum power output -OSPL- output sound pressure level 2. -compression

what are the 4 noise reduction strategies for fluctuating noise

1. DSP 2. binaural fitting 3. directional/multiple microphones 4. compression (for faster noise)

what are the 5 noise reduction strategies with constant noise

1. DSP dynamic noise reduction algorithms 2. reduce low frequency amplification 3. directional/multiple microphones 4. binaural fitting (squelch effect) 5. venting (open more, reduce LF)

What are the linear formulas?

1/2 gain NAL

what was the first prescription and who was it introduced by

1/2 gain by sam lybarger- 1944

what are the prescriptive procedures

1/2 gain rule POGO berger NAL

Directivity Index: Frequency specific DI's are sometimes plotted as a graph: for every 1 dB in sensitivity is a ____% change

10

directional mics FBR=

10-30 dB

what is the dynamic range of a normal hearing person

100 dB

Physical Designs of microphones: Electret design provides extended frequency response for what frequencies?

100-15000 Hz

with a loss of 40 dB dynamic range is 100 calculate the compression

100-40 dB= 60 100/60 = 1.6 1.6: 1 (this is what we normally see)

for POGO what frequencies is the 1/2 gain for

1000-4000 Hz

fabry & stypulkowski found that a _____dB re NAL in low frequencies and a boost for high frequencies maximizes______

12 dB speech intelligibility

Super-Cardioid Polar Plot/Pattern has significant attenuation for signals arriving from about _____ degrees to ______ degrees

130; 230

good feedback cancellation algorithms can provide how much gain

15 dB + more stable gain

remote microphones result in a ____ to ____dB improvement in ______

15 to 20 dB improvement in SNR

approximately ____% of people who own HAs don't wear them

15%

Where is the bulk for SII (frequencies)

1500-4000Hz

directional microphones were first introduced when? which included _____% of BTE HAs

1971; 20

when was the first version of the berger developed

1976 and revised in 1984

until when all hearing aid amplifiers were single channel

1987

what ratio = no compression what ratio = lots of compression

1:1 10:1

Directional Microphones: the single cartridge design has ____ microphone(s) and _____ port(s)

1; 2

Many manufactures attempt to achieve a +/- ___ dB from mic

2

Super-Cardioid has _____nulls

2

What does a BiCROS system comprise of?

2 mics, 2 amplifiers, and 1 receiver

What is the typical AI-DI range for directional mics?

2 to 5dB

Occlusion: with a shell in the ear, revit reported pt ear amplifies by ___-____dB

20-30

input increases: 20 dB output increases: 10 dB calculate it

20/10 = 2 ratio is 2:1

input increases: 20 dB output increase: 2 dB calculate it

20/2 = 10 ratio: 10:1

Body Baffle: Erber's study suggested SPL at mic of body aid increased 5-10dB from ____-____Hz. Decreased 5-15 dB from ________-_______Hz and no significant effect above what?

200-800; 1000-2500; 3000

Statistics of T-coils in 2001= in 2021= in Europe=

2001= only 30-40% of HA sold in US had t-coils 2021= ~65% of HA sold in US had t-coils in Europe 85-90% have t-coils

hearing aids perform optimally between

3-6 ft

speech has a dynamic range of what

30 dB

since a 6-10 dB increase results in a doubling of perceived loudness this would result in the pts voice being up to __ times louder and leads to what?

3; rejection

D-Mic: how many inlets? omni-directional mic has how many openings? Hyper-Cardioid (directional) has how many openings? (3)

3;1;2

The FCC requires a t-__/m-___ rating

3;3

typically compressing, shifting or transpose in what frequencies

3k-4k hz or higher

Cardioid DI

4.8 dB

Bi-directional DI

4.8dB

goal of frequency lowering #2

4000 Hz consonant is delivered to the patient at 2000 Hz, it won't sound the same, the altered signal may be better than not hearing

Maximum sensitivity for cardioid is ~_____ degrees

45

for flat audiograms (between .5-4 kHz) how many channels do we need

5-8 channels (2-4 channels would do a decent job)

Supercardioid DI

5.7dB

Directivity index is calculated at

500, 1000, 2000, 4000Hz

SNR with a 50db loss= with a 80db loss=

50= +6 80= +12 with each 1dB improvement in SNR you get a 10% improvement in word recognition

What is the Articulation Index (AI) based on this audiogram?

56/100 or 56%

Multiple Microphone Arrays: more than __ does not result in greater benefit. Hearing aids fit today, utilize a "microphone array" ___ mics, two on each aid

5; 4

Hypercardoid DI

6 dB

Occlusion: a ___-___dB increase results in a doubling of perceived loudness

6-10

Sound shadow/head shadow: fairly significant reduction, Near ear-far ear = ___dB difference for spondee words

6.4

music has a dynamic range of what

60 dB

Ear canal resonance: ears reach adult like resonance at what age?

7

study suggests how many channels are needed to match prescriptive targets

7 channels -with 90% or better accuracy

for sloping, precipitously sloping and rising configurations how many channels are needed

8-16 channels

Occlusion: a 2mm vent results in a decrease of about ____dB at 200 Hz

8.5

what percentage of people with aidable HL will benefit from dir mics

80-90%

what is the nyquist frequency for speech

8000 Hz x 2

Bi-Directional: Nulls are present at _____ and ______ degrees

90; 270

What is the Articulation Index (AI) based on this audiogram?

92/100 or 92%

in 2013 _____% of aids dispensed were DSP

98.6%

> the noise?

> the reduction in intelligibility (most difficult with topic change)

Which class of amplifier is the oldest, least expensive, and does not produce a lot of gain

A

What are the three classifications of the final stage amplifier?

A, B, D

Both head and body can rearrange sound waves (as well as clothing) and is more critical for body aids but is now used for what?

ALDs

Subtracts electroacoustic parameters based on what? (6)

Age Gender Experience level Severity of loss Native language Individual differences

What is the SPL-o-gram?

An audiogram that has LDLs and fitting targets

what type of method is DSL?

An output method

Waveforms that mimic acoustic waveforms they represent

Analog

What does AI-DI and SII-DI index stand for?

Articulation index and speech intelligibility index

Individuals with hearing loss have a loss of __________ and _________ can occur

Audibility; Distortions

Which Class of amplifier is referred to as push-pull circuit?

B

What are the 6 hearing aid styles we need to pay attention to?

BTE, ITE, Canal, CIC, RITE, IIC

What is the benefit of T-Coil?

Background sounds are not amplified so signal-to-noise ratio improves from telephone conversation

What type of polar plot is this?

Bi-directional

What are the two secondary polar plots/patterns?

Bi-directional and Supercardioid

Higher Order Directional Mics: are used today in all major manufactures HAs and work how?

Binaural wireless technology combines two mic's on each aid

What is a BAHA?

Bone anchored hearing aid

DSL 5 accommodate for comfortable listening in what?

Both quiet and noise

What is the main difference between a CROS system and a BICROS system?

CROS: better ear is normal to mild high frequency loss. BICROS: better ear is mild to severe hearing loss

How do D amplifiers differ?

Can produce higher outputs, decrease distortion, extend high frequency emphasis, lower battery consumption and smaller size

What type of polar plot is this?

Cardioid

What is the squelch effect?

Central Auditory Nervous system compares and integrates different signals being received at each ear.

DSL Who it's used for? How much gain?

Children- bc want them to make all speech sounds audible Pts with sudden HL - can handle more HF gain bc are used to normal hearing Has the most gain

How do omni-directional microphones work?

Closed box divided into two chambers by a thin diaphragm, sound enters through the mic port, sound pressure changes causing the diaphragm to vibrate and the vibration creates an electrical signal

Describe the pathway from communication strategies to cochlear implants

Communication strategies -> PSAP -> ALD -> OTC -> prescription HA-> cochlear implants

DSL 5.0 Optimize protocols for what?

Compression circuitry

What are the different physical designs of microphones?

Condenser microphone, carbon, electromagnetic, ceramic, Electret, and Microelectromechanical system

Manipulation of Polar Plots is doing what?

Constantly changing

DSL5.0 maximizes number of acoustic cues contained in what?

Conversational speech

How do you determine AI based on dot audiogram?

Count number of dots that are audible (above patient's threshold)

For children and suspend onset HL which formula?

DSL bc provides more HF gain that is needed for children speech development and sudden loss pt are used to the sound of normal speech

Individuals with hearing loss have a(n) __________ (easier/difficult) time in noise

Difficult

Represents signals as a string of numbers

Digital

What are the two different ways we can manage difficulty in noise?

Digital noise reduction and directional microphone technology

What is the the only thing we can do to improve SNR

Directional Microphone Technology

Duel-Microphones: output from one microphone can be delayed electronically and then subtracted from the first. This results in what?

Directional Response

Directivity Index: the higher the DI, the more what?

Directional it is and more likely will do well in noisy environments

A lot of gain and can cause what?

Distortions

NAL-NL2: as HL becomes worse in degree and slop what happens to speech?

Distortions

Digital Noise Reduction (DNR):How does Speech Enhancement technology work?

Drags noise to the envelope of speech

What type of microphones are most common today?

Dual-microphones

NAL-NL1: audibility vs effective audibility

Effective audibility - how much information can be extracted from speech sounds

Physical Designs of microphones: this type started in 1960's and is still used today

Electret

Physical Designs of microphones: which design is made by a thin metal?

Electret

Digital Noise Reduction (DNR) changes output to do what? (2)

Enhance speech and attenuate sound

NAL-NL 1 attempts to _____ rather than preserve the loudness relationships amongst speech frequencies

Equalize

Why is AI-DI range for direction mics important?

Every dB improvement in AI-DI results in an increase in speech understanding of 10%

DSL 5.0 objectives: avoids what?

Excessive loudness

sounds will not hit diaphragm simultaneously, diaphragm vibrates and electrical signal results so how does this get resolved?

External port delay

What do Bi-Directional polar plots pick up?

Front and back Equally

How does the brain dictate the primary sound source? (7) things

Fundamental Frequency, Harmonic structure, Suprasegmental (stress, tone, loudness), Location, Timbre, Rate, and Visual cues

For NAL targets for someone with precipitous sloping there will be no targets in the higher frequencies, but this does not mean there is no_____

Gain

NAL-NL1 fitting method is considered what kind of method?

Gain method

Dual-Microphones: have _________(less/greater) flexibility

Greater

adaptive polar plots

HA automatically samples all polar plots and determines which are around the patients should be maximally reduced

what happens when fixed release times are too short

HA will go in and out of compression often

fig 6 said for gain at 40 the formulae was designed to correct hearing to

HL -20 dB -20 dB

Disadvantages of Eye glass aids (2)

Heavy and inconvenient to repair

With N AL, we see a sharper decline in ____ frequencies

High

The SII has more weight given to ________ frequencies

Higher; 6000-8000Hz

Directivity Index: Which Polar Plot/Pattern has the best response to manage noise in those environments and what is the DI index?

Hyper-Cardioid; 6dB

What type of polar plot is this?

Hyper-cardioid

One directional microphones can be known as what?

Hyper-cardioid polar pattern

what type of Polar Plot/Pattern tends to be/have the best response with hearing aid use

Hypercardioid

sampling rate is expressed in

Hz

the other 2 formulae for digital hearing instruments

IHAFF- independent hearing aid fitting formula fig. 6- figure from article

which hearing aid is placed and removed by a professional?

IITC (invisible in the canal)

For ____ need to mark ear mold impressions to insure mic openings are in line

ITE's

What does "in Situ" mean?

In place- includes factors that influence output

Compression ratio is _____ slightly for mild-moderate losses

Increased

NAL-NL2 differences: _____ gain for adults than NL 1

Less

___gain for adults at ____ input levels

Less Loud

What is the major difference between an NAL - NL2 and NAL - NL1?

Less gain in NL2

New version of DSL(v 5.0) accounts for what?

Limitations in noise Establishing MPO to maintain user comfort

NAL-NL1 What it's used for? How much gain?

Long term users - bc prefer more high freq gain Men? - prefer more gain Has more HF gain

NAL-NL 1 prescribes ______ frequency gain than most other fitting methods and less ______ frequency gain for severe hearing loss than other prescriptive methods

Low high

What is the difference between directional flat and directional low-cut filtering?

Low cut provides more reduction of low frequency amplification

What is a problem with directional mics?

Low-frequency roll-off

What does the "m" and "I/o" stand for in DSLm[i/o]?

M- multilevel family targets (based on age and etiology) I/o- input/output level

Why do we want to use Volume control if HAs adapt?

MCL varies due to auditory fatigue, changes in ET function

T coils concert ____ energy to____ energy

Magnetic to electrical

NL 1 fitting method: provides gain recommendations that do what?

Make loudness of speech bands equal across a wide band of frequencies

What is the primary goals of NAL formulas? (2)

Maximize speech intelligibility Using predictive models for speech intelligibility

What are the goals for NAL-NL2 (2)

Maximize speech intelligibility for levels around compression threshold Keeping overall loudness at or below that of normal listeners

Physical Designs of microphones: Which design is only used in Starkey hearing aids?

Microelectromechanical systems (MEMS)

Higher Order Directional mics: includes what?

Microphone Arrays

Previous users prefer _____ gain then new users

More

For DSL: we have ______ HF and ______ LF compared to NAL

More More

Makes prefer _____ ______ then females

More gain

BTE Directional Hearing Aids: instead of completely covering the microphones, how is it managed now?

More of a hood, moisture rolls off but microphone still exposed

The more HF we give what happens to the pt perception

More uncomfortable

For reoccurring patients which formula

NAL 1

For first time users and geriatric patients what formula

NAL 2 bc provides less gain

what is the order of how NAL was revised

NAL, NAL-R, NAL- RP (correction factor)

Nal- Nl2 Who it's used for? How much gain?

New users with gradual hearing losses - easier to adapt bc less HF gain Geriatric patients- easier to adapt bc less HF gain Least amount of HF gain

When looking at NAL targets for someone with precipitously sloping you will see what?

No targets in the higher frequencies

Principal of DSL: what does it do for loudness?

Normalizes it Perception would be like a normal hearing individual

What is the ability to utilize the opposite ear to the sound source to hear signal?

Off-Side hearing

What type of polar plot is this?

Omni-directional

What are the three primary polar plots/patterns?

Omni-directional, cardioid, and Hypercardioid

What are the different classes of hearing aid microphones? (4)

Omni-directional, directional, dual microphones, and microphone arrays

When to use Omni versus Directional mics?

Omni: talker located other than front, background noise absent/quiet, smaller rooms. Directional: talker located in front, moderate background noise, larger rooms

Dual Microphone (D-Mic) design has what type of mics?

One omni-directional and one directional within the same capsule

DSL method: what is the primary interest?

Output at TM (not gain)

Who are PSAP used for?

People with normal hearing

What does PSAP stand for?

Personal sound amplification products

Which hearing aid company is big into CROS systems?

Phonak

Microphones are classified by what? (3)

Physical Design, Classes of microphones, and Polar patterns (or plots)

What is the primary purpose of the T-coil?

Pick up signal from telephone receiver

How do hearing aids work in noise?

Picks out speech rather than noise (not always the case)

What classification of microphones is most important to know?

Polar Patterns (or plots)

Microphones can be characterized through what?

Polar Plots

What are the 3 stages of amplification for HA's?

Pre-amp associated with microphone, processing stage, output stage

The ear canal resonance can also be known as what?

Preamplifer

The brain can manage a complex waveform by sorting through what is important to us. We can track one voice in the presence of another is called what?

Primary sound source

If the patient does not have a smart phone and dexterity issues, what can we do?

Provide a remote

What type of HAs have always had directional microphones?

RICs

Microphone techniques: Evidence supports what?

SNR improvement

What is SNR?

SNR needed for HIP to achieve 50% word recognition scores compared to people with normal hearing

What do Supercardioid polar plots pick up?

Same as hypercardioid but reduces sensitivity

Dual-Microphones: what is managed digitally?

Signal delay and subtraction

NL 1 fitting method: what are gain targets for soft, moderate, loud inputs?

Soft- 50 dBspl Moderate-65 dBspl Loud- 80 dBspl

Directional Microphones: how does the single cartridge design work?

Sounds from the two ports arrive on either side of the diaphragm

What is Multi-Speaker Access Technology?

Speech Enhancement technology

What is the difference between hyper-cardioid and super-cardioid polar plots/patterns

Super-Cardioid is less sensitive in the back

What type of polar plot is this?

Super-cardioid

Dual-Microphones (D-Mics): a switch is located on the faceplate of some aids to do what?

Switch from omni-mode (in quiet) and directional (in noise)

NAL non-linear version 1 and 2: originated from? Evolved from what?

Sydney Australia Linear based formula NAL-R

Individuals with severe to profound loss depend on what cues?

Temporal and amplitude

What are the three cues for speech importance?

Temporal, Amplitude, Frequency

What affects the timing of the signal?

The damper

Directional Microphones: the bigger the case the more you can separate the microphones so what dose this mean for custom products?

The smaller we go, the harder it gets to separate

Not everyone with hearing loss will not be able to use what?

The temporal, amplitude, and frequency cues

Patients mist be able to do what in their instrument?

Tolerate gain

Frequency dependent gain for tonal vs non-tonal: what is the difference?

Tonal- changes meanings in language that does not occur in English

How can we counsel patients about polar plots?

Train them to look where the sound is coming from

What are DSL factors that influence fitting? (3)

Transducer for testing Ear canal resonance Style of hearing aid

Describe Dual-Microphones

Two separate omni-directional microphones, each has its own separate inlet

what is IHAFF also referred to as

VIOLA -visualization of input/output locator algorithm

DSL i/o was developed to address

WDRC hearing aids

expansion has lower knee point than what

WDRC kneepoint

what is compression

a monitoring circuit built into the hearing aid

explain loudness growth for a normal hearing person vs SNHL

a normal hearing person hears soft sounds as soft. with a HL it takes more intensity to just barley hear those soft sounds therefore we need to amplify them just to hear those (this is the critical reason on why we fit hearing aids) sounds (the graph)

for remote microphones a 15 to 20 dB improvement in SNR is translated as

a significant improvement in speech intelligibility -1 dB improvement in SNR results in 7 to 10% improvement in performance

what are adaptive polar plots best with

a single noise source

what are programmable aids

a system that allows for programming, reprogramming and changing frequency response, gain, maximum output, and some compression characteristics

Dual-Microphones: describe the pathway

acoustic to electrical energy then combined electronically

_______ processing by premium features can potentially improve scores on tests in lab

acoustical

Volume controls (VC) allows users to do what?

adjust amount of gain they are recieveing

who can understand speech in moderately noisy environments

adults

AI-DI/SII-DI Adults= Children=

adults= when speech intelligibility is at or less than 80% it is important to start talking to adults about hearing instruments children= when speech intelligibility is at or less than 80% they should DEFINITELY be fit with amplification

receivers used with HAs

air conduction bone conduction output transducer convert an amplified electrical signal back to an acoustical signal

SII-DI 1.0=

all of the speech information is both audible or usable

What was the phonak watch pilot?

along the face, you can press up or down for volume control

what is the rationale of the berger prescription

amount of gain provided should amplify sound to average speech spectrum level (55-75 dB SPL)

sounds below the expansion kneepoint are

amplified less

T-Coils: when two wires are close (in phone or other coupling device and in hearing aid) what happens?

an electromagnetic field is created

What type of programming are IITC?

analog

what should we know about the anti-aliasing filer

analog low pass filter- required at the beginning of the processing chain to fulfill the sampling theorem

modulation based schemes

analyzes signal for # and depth of modulations (speech usually has 4-6 modulations per second)

what two major things do we have to keep into account when selecting a HA selection

anatomical and visual/dexterity issues of pt

What are Microphone arrays?

any device that has more than 3 MICs if a patient is fit binaurally

digital noise reduction

any type of scheme in which a mathematical calculation is employed by the the hearing aids signal classification system to separate a desired signal (typically speech) from an undesired signal (typically background noise)

what is the goal of a linear aid

apply significant gain so normal conversation is around the middle of the HIP dynamic range

What is the baffle effect?

as sound approaches any obstacle, rearrangement of sound waves occue

what is the minimum sampling frequency for speech & what does this mean

at least 16 kHz -means the value of the voltage that represents the sine wave is measure 16,000 times per second or once every 62.5 msec

receivers used with HA: bone conduction (soft band) used for individuals with

atresia or stenos or chronic middle ear disease with drainage (makes regular HA impossible)

goal of frequency lowering #1

attempt to make HF speech signals ("s" "sh") audible at a lowering frequency

DNR attempts to do what when speech is dominant

attempts to clean up the speech signal when it appears to be dominant (+2-5 dB S/N)

according to the formulae gain overcomes what that is caused by the hearing loss

attenuation

what does attenuation stand for

audibility

goal of frequency lowering #3

auditory training may accelerate acceptance

What is an advantage of binaural hearing aids?

avoid sensory deprivation

When class D amplifiers are used in analog aids, where is the amplifier?

built into the case of receiver so less space

What is a CROS hearing aid?

contralateral routing of signal

What is RITE best for? (2)

cosmetics and gain/output

What are CIC aids best for? (2)

cosmetics and telephone use

Class D amplifiers cause a ________(decrease/increase) in distortion

decrease

TK control for pt complaint for not hearing at distance

decrease TK: so they can hear

Volume control: On BTEs, turning rotary VC down ________gain and turning it up ________gain

decrease; increase

As the t- and m- rating increases, what happens to interference?

decreases

What is the M-rating?

describes the level of hearing aid microphone compatibility within a telephone

How does a T-coil work?

detects and converts magnetic energy into electrical energy

automatic acclimatization

determine a prescribed amount of increase in gain and when that will occur (we can tell the HA when to change settings on what date..ex if pt is going out of town and we want full gain on set date)

who was the desired sensation level created for

developed for fitting infants/ children with linear amplification

Physical Designs of microphones: condenser microphones, carbon, electromagnetic, and ceramic _________(did/did not) do a good job in hearing aids

did not

for multi-channel processing we apply what

different compression characteristics to different frequency specific inputs (aka larger band widths)

Microphone techniques: are designed to be more sensitive to sound arriving from what?

different directions

what are programmable aids NOT

digital hearing aids

comfort in noise is affected by

digital noise reduction

what are programmable aids called

digitally controlled analog hearing aids DCA

speech intelligibility in noise is affected by

directional microphone technology

don't use what for music

directional mics

what is clinical proves for improving signal to noise ratio

directional mics

what is the only special feature that is widely proven to improve speech recognition in the presence of background noise

directional mics

Advantages of RITE? (2)

directional/dual mics and cosmetically appealing

Advantages of BTE?

directional/dual mics, power

directional microphones also helps noise because of

directionality and low frequency roll-off

Directivity Index: speech arriving from 0 degrees means what to the patient?

directly in front

Where are receivers located on BTE's?

directly underneath the ear hook

with the linear amplifier saturation is created causing what

distortion- this is what we can control

what is the ballpark compression ratio

divide residual dynamic range of normal hearing individual by residual dynamic range of the HIP

Dual-Microphones (D-Mics): ______(do/do not) fit on canal aids

do not

Polar Plots: Current Polar Plots: Current DSP (Digital Signal Processing) HAs are what?

dynamic and adaptive in the environment

what was the point of NAL

equal loudness across frequency bands

Omni-directional is __________sensitive to the arrival of sounds from all directions

equally

What do Omni-directional polar plots pick up?

equally all around

what is the sound aliases

essentially low-pass filter is placed before the A/D converter

definition needed to know for directional mics and S/N

every 1 dB of improvement in S/N expect 7-10% improvement in speech intelligibility (less improvement for more severe losses)

for the binary what happens

every time a doubling occurs, an additional 0 is placed at the end of the string

Advantages of CIC? (2)

excellent position for microphone and most cosmetically appealing

what was the negative consequence of WDRC

excessive amplification of low-level input signals increases audibility of low-level environment noise and noise generated by hearing aid

what was the first non-linear perceptive formula

fig 6 -killion and fikert-pasa (1993)

what are the "big three" non-linear prescriptive fitting formulae - what we use today

fig 6 IHAFF desired sensation level

what is proven to preform equally well

fixed and adaptive dir mics

what is the greatest benefit of the DSP aid

flexibility!! we can make so many changes on site!!

what can stable gain make a big difference on

for speech audibility and improve intelligibility

speech shaped intensity is on what spectrum

frequency

sampling is how the _____and____ of sound become represented by numbers

frequency and intensity

what feature on DSP aids do manufactures choose

frequency lowering (compression, transposition)

What do Hypercardioid polar plots pick up?

front and back ( but more emphasis on front)

What do cardioid polar plots pick up?

front and sides but not back

power of receiver accommodate different hearing loss and varies by what?

gain

if noise is dominant what happens in DNR

gain for everything is reduced

What are BTE best for?(2)

gain/output and directivity

gain for mild and moderate example with a moderate loss

gain65= 90 dB (mean MCL for moderate HL) - 65 dB (normal conversational input) = 25 dB gain

The __________(greater/less) the hearing loss, the less importance frequency cues play

greater

What was the problem with phonak watch pilot?

had separate batteries and when one died, you were screwed

Disadvantages of BTE? (2)

harder to manipulate and susceptible to wind noise

Disadvantages of RITE? (1)

harder to manipulate due to flexibility of wire

Cardioid Polar Pattern is _______shaped and more sensitive to sounds from the _________ than the ________

heart; front; back

Class D Amplifiers has an extended _____(low/high) frequency emphasis

high

Ear canal resonance: smaller canal = more what?

high frequency amplification

what does the compression limiting consist of

high kneepoint high compression ratio

Ear canal resonance: results in an increase in amplified sound in the ______ frequencies _______-_____Hz

high; 2000-4000

Class D amplifiers can produce _______(lower/higher) outputs

higher

speech is

highly redundant (adults have good auditory closure skills)

SNR and level effected

how much noise reduction (10 dB) and when does it start (with 60 dB SPL of noise or 80 dB SPL of noise)

what is compression ratio

how much the signal is being compressed

Polar Plots are used to dictate what?

how sensitive a hearing instrument to different sound sources

how is the signal analyzed in each channel of the HA

if classified as noise, signal is reduced, if classified as speech, signal is enhanced

Microphone techniques use outputs from 2 or more mics which do what?

improve SNR through spatially dependent sound sensitivity

Directivity Index: the ability to do what?

improve the SNR in a diffuse noisy environment with speech arriving from 0 degrees

TK control for pt complaint for feedback

increase TK

TK control for pt complaint for breathy sounds

increase TK: to reduce the gain

for music we increase what

increase the dynamic range to ensure output set to patients tolerances

Volume control: On ITEs turning wheel toward noise/face ________volume. Turning the wheel toward the back of the head ________volume

increase, decrease

what does IHAFF stand for

independent hearing aid fitting formula -12 audiologists

what = output

input + gain, which is at the eardrum

for the linear amplifier what two things are increased and at what degree

input and output are increased simultaneously at a 45 degree line

What is loudness summation?

input from both ears is summed by the brain

what is 1:1 ratio

input increases by 1 output up 1

10:1

input increases by 10 output up 1- this is considered a lot of compression

Low-Frequency Roll-off: gain compensation for directional mics ________(is/is not) necessary for patients with good LF hearing

is not

dynamic range

is the ratio of the maximum signal level to the minimum signal level (example 115 dB SPL- 25 dB SPL= 90 dB dynamic range)

Why are magnetic receivers the weakest link in hearing aids?

it is susceptible to both wax and moisture

what is the DSP definition (what 7 things can it change)

its a system that digitizes sounds and allows for programming, reprogramming, and memorizing frequency response, gain, maximum output, and compression characteristics

what is bluetooth technology and how well does it work up to ft wise

its cord replacement, works up to 30 ft

What is a rotary volume control?

keeps rolling up even when limit is hit

Ear canal resonance: since smaller canals have high frequency amplification what does this mean?

kids will have an intolerance to HF

Custom products: the further we separate the mic and receiver the ______(more/less) feedback

less

For loudness summation _____(less/more) gain is needed

less

ITE Directional Hearing aids: ______(less/more) effect of the directional microphones on these devices

less

Physical Designs of microphones: Electret design is made with a thin metal which is ________(less/more) sensitive to vibrations

less

what does hard-wired mean

less ability to make changes to the HA -the manufactures can only pick this

wide DR=

less compression & happens sooner

Disadvantages of canal aids?(3)

limited amplification, small controls/batteries and cannot be used for small ears

Disadvantages of CIC?(5)

limited amplification, small controls/batteries and cannot be used for small ears, no directional mics and deep canal fitting required

Disadvantages of ITE? (3)

limits to power ,susceptible to wax, and more occlusion effect since less room for venting

1:1 is what type of aid

linear

clinically NAL-R was the most widely used approach for

linear amplification

several prescriptive formulas were developed for what

linear amplification

below compression threshold, most hearing aids amplify

linearly

why is frequency lowering important for female voices

listeners need audibility up to 9000 Hz to differentiate /s/ versus /sh/

Having two ears allows us to what?

localize

linear DR=

longer, more compression & happens faster

what does DNR do to clean up speech

looks for gaps between speech signals, and reduce the noise for these gaps

what does the classification system of the DNR do

looks for very sharp peaks in the onset signal, sound is reduced giving that noise a duller sound

What is the vertical t-coil used for?

loops

IHAFF wanted to complete what scaling and relies on what

loudenss -relies strongly on direct loudness measurements

compression limiting (output) is used for

louder inputs

what is the biggest thing we have to manage

loudness

what are the advantages of binaural hearing? (4)

loudness summation, off-side hearing, localization and avoid sensory deprivation

With an electronic device, you will pick up a _______(low/high) level sound/noise

low

TK adjusts over a range of what and where is its linear gain

low inputs from 40-60 dB SPL -linear gain is below the kneepoint

what does the wide dynamic range compression consist of

low kneepoint low compression ratio

start frequency

lowest frequency in the source region (like compression kneepoint) 3000-4000Hz. 3000 Hz start, 4000 Hz the target

If you do not have a t-coil what should you do to the hearing aid? (2)

maximize frequency picked up by telephone between 300-3000Hz or you can create a program

Auto phone/easy phone: some telephones have small magnets which will not trigger the switch. What can we do?

may need to add magnet onto the telephone headset

What is the articulation index?

measure in percentage of normal conversational speech which is audible

Where is all the hardware for a CROS system? (2)

mic is on bad ear and hearing aid is worn on normal hearing ear to receive signal

what is expansion referred to as

microphone noise reduction

Why do we have multiple microphones? (separation between the two)

microphones pick up and compares and chooses best option

berger and 1/2 gain tended to over amplify what type of hearing loss

mild to moderately-severe HL

What is a t-coil?

mini antenna; small electromagnetic induction coil (copper)

Disadvantages of Through-the-ear aids? (2)

minor surgery and adverse directionality

What degree of hearing loss is recommended for t-coils

moderately severe-profound

The greater the HL the ________(more/less) the SNR needs to be

more

The lesser the distance the _____ roll off you will have

more

the higher the ratio the

more compression

speech has fewer modulations with

more depth than noise

DSL provides overall

more output than other fitting methods -more low and high frequency output

Are t-coils programmable?

most DSP aid entry to premium level can be programmed and most auto phone programs work off base program

audibility and comfort in quite is affected by

multiple channels of WDRC, expansion & frequency lowering & adaptive feedback suppression

DCA and DSP hearing aids can have

multiple memories

convenience, ease of use and simplicity is affected by

multiple memories, signal classification, & trainability

what program could increase if patient is consistently turning it up

music

what does NAL stand for and when was it introduced and then when was it revised

national acoustic laboratory (what we use today) -1976, 1986- NAL-R

Through-the-ear: open fitting maintains what?

natural ear resonance

advantages of canal aids?(2)

natural position for microphone and cosmetically better than ITE

wireless HA to HA communication is

near field magnetic induction- NFMI -low power, short distance

Advantages of Through-the-ear aids? (3)

no occlusion, no heat/moisture build up and no discomfort from mold

when the circuit reduces the gain what doesn't occur

no peak clipping or distortion would occur

what did evidence support with premium technology

no statistically significant difference in outcomes between premium and basic-feature devices

CROS systems allow for what?

noise reduction

SII-DI 0=

none of the speech information is audible or usable

What are canal aids best for?

nothing

the binary implies the use of

one of two numbers either a 1 or 0

what is the name of the BAHA used today?

osseointegrated implant

what was the first commercial DSP aid

oticon digifocus- 1996

what method is DSL considered and who is it generalized to now

output method -generalized to adult population

What is the front-to-back ratio?

output of hearing aid in response to a speaker placed at 0 degrees minus the output of a hearing aid in response to speaker placed at 180 degrees

what = input

output-gain

what = gain

output-input

signal classification is taking whats going on around & changing what types of things

overall SPL, frequency-specific SPL, modulation rate, amplitude depth

source region

part of the spectrum where information is moved from

target region

part of the spectrum where information is moved to

Who used a BiCROS?

people with HL in better ear and an unaidable hearing loss in the other

what can be modified but only those that the manufacturer allows

performance parameters

what is stable gain

person can talk, eat, move around ect. and the HA will not go into FB

What is the horizonal t-coil used for?

phone

How do you have to position the phone with a t-coil?

phone receiver up and back

What is an issues with T-coils?

placement of coil varies in hearing aids

What are some disadvantages of t-coil?

placement varies, noisy, very steep LF roll off

what is the compression threshold/kneepoint

point where compression starts

Hearing loss causes sound to be what?

poorly defined within the cognitive system

Advantages of body aid(2)

power and durability

what does POGO stand for

prescription of gain and output

algorithm=____which is

prescription....which is a mathematical rule or process to solve a problem

multiple memories is known as what and can do what

programs and can manage different listening environments

what is the assumption when mirroring the audiogram...if the patient has 45 dB HL

provide 45 dB of gain to move threshold to "normal"

what is the goal of a compression aid

provision of progressively less gain for greater input intensity levels (aka squash it all into a small dynamic range)

Who uses a CROS system?

pt with unilateral loss with normal hearing on other side

Who are OTCs for?

pts with mild-moderate loss

What are class D Amplifiers also known as?

pulse-width modulated amplifier or switching amplifier

Where are class C amplifiers used for? HA's

radio transmitters, no

for music we raise what

raise compression kneepoint- we make it more linear

what is compression range

range of inputs where compression occurs

What is the directivity index?

ratio of sensitivity for frontal sounds relative to the sensitivity averaged across all other directions. measures how directional the hearing aid is

What is Beta (single cartridge design)

ratio of the internal time delay to the external time delay

expansion allows for signals below first TK to

receive reduced gain rather than maximum gain

TK for greater gain

reduce the input we get more of a gain

venting ________(reduces/enhances) the directional effects.

reduces

with expansions when reducing low level environment sounds it also

reduces low level speech

what was the goal of IHAFF

restoration of normal loudness perception

beyond 6 ft of a hearing aid what happens

reverberation and the inverse square law lower the signal to noise ratio

what is important as mic ports start becoming clogged and what might happen

routine maintenance -this will affect performance of mic

What is the auto phone/easy phone?

same as other t-coils but use a magnetic reed switch (not programable)

what was carharts comparative methods goal with HA selection in 1940s

select a HA that provided maximum benefit using a speech method

Class B amplifier has separate amplifiers that do what?

separate amplifiers used to amplify the positive portion of signal and negative portion of the signal

Super-Cardioid has a smaller lobe at 180 degrees, but the lobe is _____________ and _____________ that that for the hyper-cardioid

shallower; narrower

what did thornton-raffins evidence show with speech scores

showing two speech discrimination scores need to be very different to be significant

what does the signal of the multi-channel do

signal splits into various frequency bands- passes through separate circuit paths

What is a Trans Ear Bone Conduction Hearing aid used for?

single sided deafness

For the baffle effect, the amount of change in sound intensity will depend on what 4 things?

size of obstacle, angle of incidence, material of obstacle, and flatness of obstacle

WDRC (input) is used for

soft inputs

TK for less gain

softer inputs

what can allow the hardware to do more or different things

software updates

improved speech intelligibility

some evidence now supports improved speech indelibility with use of DNR

How does through the ear aids work?

sounds delivered to outer ear canal through a titanium tube inserted into soft tissue

How does the Trans Ear Bone conduction aid work?

sounds received on dead side and signal is transferred to opposite side via BC

what is the negative part with phase cancellation

sounds that may not be FB is detected and then would create actual FB- sending an out of phase signal

different programs are used for

specific listening situations

what was the goal of prescriptive fitting formulae early methods: what was the focus

specify the performance characteristics of the patients HL -gain was the focus (most concerned about audibility)

what should be lowered if patient is consistently turning the gain down

start-up gain

what are the compression characteristics

static dynamic

What is the T-rating?

t-coil compatibility within a telephone

Advantages of ITE? (2)

takes advantages of pinna effect and easier for pts to manipulate

what is sampling

taking pictures or snapshots of the signal at evenly spaced intervals -the rest of the waveform is discarded -few samples or many samples

What are ITE's best for? (1)

telephone use

sampling rate =

temporal aspect

what is compression limiting

the HA amplifies linearly until you get to high output levels High knee point high compression ratio

what happens when fixed release times are long

the HA will continue to compress after loud sound ceases

what is frequency response

the amount of response from the gain

with compression what better fits the patients hearing loss, this is our goal to fit for the pt dynamic range

the changes of the amount of gain the HA circuit adds to the input signal

what is the basic component of any DSP system

the clock

with ratio HIP the greater the loss

the greater the compression ratio needed

what is it called when compression begins

the knee point

why is input compression intended for mild-moderate SNHL

the larger dynamic ranges (MPO fluctuates)

what is the null of the polar plot consistent with

the location of the noise source

what did DSL find

the long-term average speech spectrum consisted of more low-frequency energy and less high frequency energy

When talking about Lobes and Nulls, which is the blind spot?

the null

the sampling rate indicates what

the number of samples that are taken during one second

why is output compression used for children

the output controlled to allleviate chance of reaching damaging output levels

turning down VC constantly can be bad because

the patient may never adapt to prescription

what is MPO/OSPL defined as

the point at which hearing aid stops increasing amplification

what is the process that must occur with sampling

the process that must occur during which the continuous acoustical signal is converted into discrete digits

what is "squeezes"

the range between soft and loud speech into the residual DR

what do linear aids provide

the same gain regardless of the input

Bi-directional: Not sensitive to sounds arriving from where?

the sides

as the sampling rate increase what happens

the signal looks more like continuous time representation shown above it

what limits the amount of control we have with each aid

the size

what is the attack time

the time for monitoring circuit (compressor) to sense presence of loud signals and turn the amplifier down

compression in analog aids is where

the volume control located in circuit dictated if compression was input or output

how can programs vary

they can vary in terms of frequency response, compression characteristics, other features

closed platforms of HAs

they have an inherent set of processing rules that cannot be changed by the dispenser

adaptive dir mics are easier to use because

they may translate to better benefit and satisfaction

why was DSL important for children

they need to hear their own production of HF consonants to acquire speech

open platforms of HAs

this allows the dispenser and patient to quickly and easily access a variety of distinct signal processing algorithms

fig 6 calculated what

three categories of HL (not good for HL over 70 dB HL)

what is the release time formal definition

time is takes for the output signal to increase to within 2 dB of its final value following a decrease in input level from 90 dB to 55 dB SPL

what is the attack time formal definition

time taken for the output to stabilize to within 2 dB of its final level after the HA increases from 55-90 dB SPL

what is the ability of DSP aids which makes them easier to use

to analyze the signal and make decisions for the patient, which makes HAs easier to use

Why is Front-to-back ratio used?

to check directivity in a hearing aid to ensure functionality

What is the goal of the articulation index?

to create a "real-world' measure of directivity

what was the goal of the 1/2 gain

to get average speech 65 dB SPL inputs near expected MCL

what do polar plots default to

to hypercardiod in diffuse fields of noise

What do Through-the-ear aids claim?

to increase clarity and improve comfort

what is the goal of the wide dynamic range compression

to provide more gain for lower input signals than for higher input signals (acts as IHC)

how is DNR designed

to reduce annoyance of certain transiet sounds

negative impact of low kneepoints release results in

too many soft sounds amplified

room reverberation does what to speech

too much reverberation reduces speech intelligibility

What is the AI- Count the dots?

total of 100 dots in "speech banana"

BTE Directional Hearing Aids: where is the front mic? (expect phonak)

toward the top

what is frequency lowering affected by

transposition, compression, or shifting

Disadvantages of body aid (2)

ugly and noisy

what HL is not good for dir mics

unilateral

how do we optimize frequency lowering

use the smallest amount of frequency lowering possible to obtain largest improvement in audibility

What were BAHA's used for and what are they used for today?

used to be conductive loss but now for single sided deafness

Why do we want to weigh each band appropriately for AI?

used to determine how successful a person will be with amplification

what are multi-channel HA

uses 2 or more circuit paths

what does the clock use in the HA

uses fixed vibrations of a quartz crystal to send a steady stream of pulses to the microprocessor

for home environments what is the best solution for improving hearing in noise

using remote microphones and other ALDs

what are single channel HA

utilizes a single circuit path through which all frequencies pass -all frequencies processed together (this allows less manipulation)

with directional mics what will enhance environment performance

utilizing the best positioning - we need to counsel patients to make a beam forming mic

Higher Order Directional Mics: HAs used to connect for ________ but now what can they do?

volume; talk to each other to figure out what to amplify

If a patient does not have the dexterity or would rather control volume via app, what can we do?

we can disable the hardware

follow-up counseling with pt

we evaluate wear time, monaural vs binaural, which programs are used, which used enabled features are being used

what is aliasing

when sampling rate is not high enough and error occurs known as aliasing (visualize an image that will look rough as opposed to smooth)

how is adaptive feedback suppression activated & how do we check this

when the HA detects the presence of FB -we check it by placing our hand over HA, FB should occur and then diminish

what does the monitoring circuit of the hearing aid do

when the output approaches saturation, the monitoring circuit reduces the gain

what are we not sure of for frequency lowering

who it will work for -a dozen peer-reviewed studies on modern frequency lowering techniques, no consistency across studies

what was the second commercial DSP aid

widex, it followed with senso in 1996

Dual-Microphones: if you have a signal you want to cancel, you want to make sure what?

you have a net zero

How long do batteries last in IITC (lyric)?

~120 days

How far away do you want to be for directional microphones?

~20 feet

formulae for digital hearing instruments what are the most important 3

1. DSL-desired sensational level 2. NAL-NL1 (non-linear) 3. NAL-NL2

Gain reduced ____-____ for binaural fittings, greatest for ___inputs

2-6 Loud

what has the most dynamic range

a human ear

# of _____may be less than # of ____

bands channels

what are the bands of a hearing aid

bands are also known as handles....its how dispensers can adjust response of the hearing instrument

why does mirroring the audiogram not work for us

because of the dynamic range aka the peoples LDLs

value=

benefit/cost

The higher the AI-DI the _______(better/worse) performance in noise

better

What is a BiCROS?

bilateral routing of signal

the principles of DSP

binary code sampling quantization aliasing

daily cost of HA use, what should we explain to a patient

binaural aids costing $5000 could be you spending $2.73 a day on starbucks

in digital aids what is the mathematical calculation algorithm

both WDRC (input) and compression limiting (output) compression occurring

How is Magnetic reed switch (MRS) activated?

by teal, static or permanent magnet (found in handset of most standard telephones)

digital aids today provide what

capability to make product function linearly

Digital Noise Reduction (DNR): are most modulated based, how do we do this?

carrot passage

DNR does ____ & ____ of listening

comfort & ease

fig 6 showed us that mild HL demonstrated what

complete recruitment at high input levels

at high output levels the HA

compresses a lot, we should never reach the point where peaks are clipped

what is not simply a gain control

compression in analog aids

what two things do we use in HAs today

compression limiting and WDRC

Con's for "hearables" (1)

consumers can purchase with no professional input

how does DNR work

filtering and subtraction is used

What are the two purposes of the T-Coil?

for telephone use and assistive listening devices (neck loops and loop systems)

who was POGO introduced by

gerry mccandless 1983

what is the release time

input level falls in intensity, monitoring circuit sense change and release amplifier

what is the opposite of WDRC

input signals below the compression threshold (TK) receive reduced gain rather than maximum gain

What do you have to keep in mind with the CROS system?

insertion loss

Having two ears allows us to localize based on what two things?

intensity differences and time of arrival

random noise

intensity-frequency characteristics like speech

How does hearing loss pertain to localization?

issues with localization

what is good for binaural connectivity for user VC & multiple memory features

limited transmission range

in bergers prescription what should be slightly reduced

low frequencies

noise tends to have the most energy in the ____ _____

low frequencies

with speech programs we decrease what

low frequencies due to upward spread of masking

what should we add to enhance bass

low frequencies- this provides a richer sound quality for music

for audibility and comfort in quiet we manipulate this by

multi-channel processing...but is this better?

activation time

onset and offset time (1-2 up to 5-10 secs- this is different then attack/release time)

frequency lowering intrinsic factors to consider (5 things)

-ability to learn to interpret new sounds -cognitive ability -age of hearing loss onset -listening experience -?? (lots of questions)

day of fitting or initial follow up what do we have to do

remind pt that the hearing aid records their use and what features are being employed, can help with adjustments

what did the fig 6 article "three types of sensorineural hearing loss article" show

required gain to satisfy loudness compression

the goal of current hearing instruments

resort normal loudness growth

what did practitioners begin to recognize in the 1960s-1970s

single words in quiet don't represent performance in typical listening environments

Class D amplifiers are _________(smaller/larger) in size

smaller

the purpose of the aliasing is to prohibit the introduction of the

sound aliases

what is gain

the amount by which a hearing aid increases the intensity of an input signal aka volume

what was the focus of the 1/2 gain

the focus was speech spectrum

according to the formulae the gain overcomes the attenuation caused by the hearing loss, and helps to overcome what else

the frequency filtering effects of sensory neural hearing losses

how does the hearing aid amplify

- all inputs by the same amount (1/2 gain) -some inputs more than others (this was before digital)

what are the two classes of hearing aids

- linear hearing aids - compression hearing aids

what are the 2 things related to dynamic compression

-attack times -release times

what are compression hearing aids used for

-available in analog aids -used in digital hearing aids

for POGO what is the reduced 1/2 gain at

-250 Hz -10 dB -500 Hz -5 dB

reduces audibility for very soft sounds not of interest to user

-internally generated noise from circuitry -very low-level environment sounds

IHAFF at minimum

500 and 3000 Hz warbled tones measured

Polar Plots: HA responds to sounds from ______degrees

360

_____ gain for children at ____ input levels

More Low

For sloping and precipitous HF SNHL what should we NOT USE and why?

NAL-NL 1 Because it prescribes less HF again than DSL

for flat and reverse heating losses what should we use and why?

NAL-NL1 Because it prescribes less low frequency gain than DSL

What are "hearables"

Wireless wearable computing earpieces that perform HA tasks with additional features

phase cancellation the HA detects the signal that is leaking back to the microphone and automatically does what

cancels the signal by adding the equal but opposite in phase signal

Ear canal resonance: anything placed in the ear what happens to the resonance?

changes; typically loss pf naturally amplified sounds

what does the pinna do?

collects sound and the shape funnels the sounds to focal point

What are IITC best for? (2)

cosmetics and telephone use

Own Voice Quality: "my voice sounds like it is hollow, boomy, echoes, feeling plugged, why does this happen?"

could be occlusion or amplification occlusion

who did a study on the support of premium technology

cox

what is our basic goal for DSP aids

create a clear signal, mimic the signal, audibility, comfort

What does the Trans Ear Bone conduction hearing aid look like?

custom earmold with small vibrator embedded

how do we avoid aliasing

an anti-aliasing filter is included prior to the A/D converter

With a BTE, you can use what to couple sound to ear.

an earmold or dome

Class D amplifiers have a _________(lower/higher) battery consumption

lower

Pro's for "hearables" (2)

lower cost and less stigma

DNR has potential to lighten what

the cognitive load- mounting evidence supporting this

since the introduction of DSP aids significant consolidation in what

the hearing aid industry

what is quantization

the process of describing the amplitude (intensity) of each sample

Body aids- Disadvantages: lack of what?

true binaural hearing

Class B amplifier is capable of higher gain (about _______of type A)

twice

loudness summation: sounds are about _______as loud compared to one ear

twice

how many types of DNR schemes are there

typically 3-4 types of DNR schemes being used in HAs today

How are most t-coils placed?

Diagonally

_____was clinically used occasionally

POGO

what is the clock managed by

algorithms

The directivity index is expressed in what?

decibels (dB)

what does background noise reduce

the intelligibility of speech for everyone

further technology advances involve significant _____costs

R&D

What does "in situ" gain imply?

Unaided SPL at the HA microphone aided SPL at the TM

What is a microphone array?

a microphone or group of microphones with more than one entry port

what might a patient report if they have a short release time

"cutting in and out" "pumping action"

what might a patient report if they have a long release time

"cutting off" "mumbling" "cant understand speech"

trainable hearing aids is known as

"data" learning (ex if the pt keeps turning up the VC the HA will catch on)

DSL primary goal

(if they've been previous HA users) audibility of speech make all speech sounds audible

a second interfering voice

(interference by many voices of equal intensity-speech babble): physical characteristics of random noise

what 3 things go with input compression

1. VC situated in circuit after amplifier 2. VC affects gain and MPO, not kneepoint 3. intended for mild-moderate SNHL

what 4 things go with output compression

1. VC situated in circuit before amplifier 2. VC affects gain kneepoint not MPO 3. higher power aids 4. used for children

what three things were collected in cox premium technology study

1. change in hearing-related quality of life 2. extent of agreement with 6 positively worded statements about everyday hearing with the hearing aids 3. reported preferences between the premium- and basic feature devices from each brand

what are the 4 building blocks of hearing aid features

1. convenience, ease of use and simplicity 2. speech intelligibility noise 3. comfort in noise 4. audibility and comfort in quite

what are the 2 things we have to remember with data-logging (aka the "benefits" we have with them)

1. day of fitting or initial follow up 2. follow-up counseling

multiple programs (memory) hearing aids have

1. digital control 2. program memory (quiet situations, noisy environments, music)

what did recruitment at high input levels tell us (2 things)

1. don't need amplification for high inputs 2. as HL increases, only a small amount of amplification is needed

what were the 4 things carhart tested in his goal for maximum HA benefit using a speech method

1. effective gain (using SRT stimuli) 2. best speech discrimination (using PB-50 word lists) 3. tolerance limits (under headphones) 4. efficiency in background noise (was easy to measure)

adaptive feedback suppression with phase cancellation (3 things)

1. introduction of a signal that is 180 degrees out of phase from the FB signal 2. purpose is for transient FB 3. still must ensure good fit

the signal processing steps of the DSP

1. microphone 2. anti-aliasing filter 3. analog to digital converter (A/D convertor) 4. digital signal processor 5. digital to analog convertor (D/A convertor) 6. anti-aliasing filter 7 receiver

the 6 benefits of DSP (what two things are most important to us)

1. miniaturization 2. low power consumption 3. low internal noise 4. programmability 5. feedback suppression 6. signal processing complexity

what are 4 things that people are typically interested in with DSP

1. quiet 2. noise 3. music 4. telephone

what are the three types of noise

1. random noise 2. a second interfering voice 3. room reverberation

what other factors may affect the performance of directional mics

1. vent size 2. mic port 3. alignment 4. LF gain