Spatial Analysis Flashcards

(46 cards)

1
Q

Why do we care about spatial analysis and binaural effect?

A

for localization, speech perception (in noise and quiet), challenging listening situations, auditory deprivation, loudness summation - 3dB boost in gain

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2
Q

Practical Considerations

A

For symmetrical HL, 1 HA or 2 HAs?
If 2 HAs, simultaneous or sequential?
If the patient disagrees, should you convince them otherwise?
What about asymmetrical HL?
If 1 HA, which ear to fit?

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3
Q

Monaural stimulation

A

stimulation to one ear - music listenign through one head phone

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4
Q

binaural stimulation

A

stimulation to both ears

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5
Q

unilaterateral (fitting)

A

given only one HA

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6
Q

bialteral (fitting)

A

givien two HAs .. benefit percent increased as time increased

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7
Q

diotic

A

sound presented to both ears, but same sound is presented to both ears

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8
Q

dichotic

A

both ears get sounds, but ears are getting two different sounds (ex R ear gets y sound and L ear gets x sound)

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9
Q

Head Diffraction (2 HAs)

A

external effect, HF

SNR
S = 60 dB HL
N = 30 dB HL
SNR = 60 -30 = + 30 dB

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10
Q

Binaural Squelch/MLDs (masking level difference)

A

MLD presenting 2 stimuli in the 2 ears.

internal effect
LF
S0N0, SpieN0. S0Npie
- subject represents the phase. therefore, 0 = means it is in phase. Pie represents 180 degrees out of phase

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11
Q

S0N0

A

phase of signal and noise are in phase together

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12
Q

SpieN0

A

out of phase = noise is in phase

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13
Q

SoNpie

A

out of phase = signal is in phase

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14
Q

Binaural redundancy (2 HAs)

A

diotic summation; 1-2 dB increase in SNR

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15
Q

Binaural loudness summation

A

at threshold, 2-3 dB increase in SNR. at MCL, 4-6 dB. at high levels, 6-10 dB… need both ears for effective loudness summation

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16
Q

Horizontal localization

A

advantage of bilateral fitting to localization: greatest effect for flat/gently sloping mod HL or severe-profound HL. For any degree of HL - bilateral advantage for localization increases with decreasing levels

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17
Q

Horizontal localization involves what

A

ITD = time difference
IID = intensity difference

ITD (0ms; .7ms - 900 azimth) typically LF <1.5kHz
IID/ILD (20 dB @ 7kHz) typically for HF >1.5kHz

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18
Q

A simple localization test involves what?

A

sound feild testing, or ask pt. to close eyes (wear blindfold) and jingle ear keys in different locations and see how many accurate points (within 20 degrees of correct direction) the pt. performs. At least ten presentations should be given in each condition tested.

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19
Q

Sound Quality (2 HAs)

A

improved clarity, fullness, spaciousness, overall quality
smaller JNDs (just noticeable differences)

20
Q

Late-onset auditory deprivation (2 HAs)

A

speech recognition abilities may deteriorate in the unaided ear - as soon as 7 motnhs
recovery may not be possible even with a HA fit later

21
Q

tinnitus

A

is a phantom sound, the brain perceives sound even thoguh it is not really there

22
Q

what percentage of people with bialteral tinnitus reported reduced effects of tinnitus while using 2 HA?

23
Q

what percentage of people with bialteral tinnitus reported reduced effects of tinnitus while using 1 HA?

24
Q

is bilateral or unilateral HA more effective for tinnitus management

25
simultaneous
get used to hearing aids all at once patient can gradually commit to owning HAs
26
sequential
cost or unwillingness to have both HA so do one at a time (wait until better ear gets worse, absolute do not want two, innsurance wont cover it)
27
sequential appraoch disadvantages
two successive periods of adjustments, more number of visits and time taken to fit is greater, being unbalanced
28
which is better? the sequential approach or the simulanteous approach?
no data on which approach is more effective, but arguements for the HA simulataneously seem more compelling. When 2 HAs are fitted at the onset, usually takes only a few hours or a few days for patietns who are going to benefit from bilateral HA to appreicated their advantages over a unilateral aid.
29
Binaural Summation
sound will be slightly louder since it is two HA
30
Prescription manipulations for low-level inputs
3 dB less gain for bilateral than unilateral fittings (soft sounds)
31
Prescription manipulations for mid-level inputs
4 dB less gain for bilateral than unilateral fittings
32
Prescription manipulations for high-level inputs
5 dB less gain for bilateral than unilateral fittings (loud sounds)
33
Prescription manipulations for slightly higher compression ratio for bilateral fittings
slightly higher input = want slightly more compression
34
bilateral fittings keep in mind horizontal localization...
for mild HL - may be worse in the aided than the unadied condition due to pinna occluded blocks all the feature behind (horizontal and vertical) and HA may obscure anatomical features that aid in localization
35
bilateral fittings keep in mind vertical localization...
normal hearing midsagittal plane ** 3^0 > 4 kHz BTE, ITE, ITC may worsen vertical localization abilities
36
binaural interference (1 HA)
condition in which you give input to both sides, the perception will be poorer than if you give perception to only one side 10% of the geriatric population
37
poorer speech discrimination when listening to binaurally as opposed to monaurally
poorer ear is interfering with being able to hear from the better ear, which is why you might have to give one hearing aid to the better ear
38
reasons for binaural interference?
signals from the poorer ear interfere with (central) auditory processing, differential aging of hemipsheres, and inefficient transmission between hemispheres
39
Cost (1 HA)
initial and recurring. one HA is less than two
40
How can u counsel fro a patient who has self image isssues? (1 HA)
greater alertness while 2 HA was proven to make an individual look younger. i understant u want one hearing aid but hear me out, there is evidence that 2 HA make you more alert wihich actually make u seem much younger because ur now in sink with things around you.
41
If the patient disagrees?
demonstrate skeptics 30/45 degree azimuth, include advantages of head diffraction, squelch, and redundancy. Loaner HAs may be helpful
42
If bilateral fitting is recommended and the patient rejects the 2nd HA, what should you do?
Document that was recommended, the rationale for the recommendation of 2 HA based on thier HL, and that the recommendation was rejected
43
Rising hearing loss people perceive more or less disability in the rising confirguration? Would u aided the rising right ear?
perceive more disability. yes just to boost those low frequencies. also right ear advantage
44
if were trying to fit a almost dead ear and a mod HL ear which would u aid?
the left because the right ear is pretty much almost gone, so its best to have at least one good ear
45
pateint has normal right pure tones, mod left pure tones. Good right SRS and very poor left SRS. WHich ear aided and why?
left may create more disortion becasue WRS are 24% (extremely poor) Audiotroy neurapthoy - neruans usually fire in sync (phase locked) but in this case something is damaged and neurons are misfiring
46
If working with 1 HA, which are to fit?
fit the ear that has the four-frequnecy average (4FA) threhsold closer to 60 dB HL. consider which hand has better dexterity which ear displays higher speech discrimination in quiet, better speech reception thresholds in noise pt routinely in situations where the talker is always on the same side pt perfer to use telephone in one ear if none of the information available suggests which ear to fit, then choose the right ear