1
Q
what are the external device components of a CI?
A
microphone, digital sound processor, coil/antenna, magnet and power source
2
Q
what are the internal device components of a CI?
A
magnet, receiving/transmitting coil, digital sound processor, stimulator for electric pulse generator, electrode leads and electrode arrays
3
Q
how does a CI convert sound into an electrical stimulation?
A
-microphone picks up the sound, amplifies and converts it to an electrical signal which goes to the speech processor
-SP analyzes the signal and converts it to digital information
-this gets sent to the external coils, which transmits both the signal and power to the internal receiver
-this decodes the signal, delivering electrical stimulation pulses to the electrode array inside the cochlea
4
Q
what is the importance of a speech processor?
A
it functions like the cochlea within the implant and it is where everything occurs in order for the signal to be digested
5
Q
what are the functions of the speech processor?
A
amplification, filter, envelope detection, compression and modulation
6
Q
tell me about amplification within the speech processor
A
used to increase signal levels and the exact level is determined by the gain of the amplifier which is defined by the ratio of output to input level
-this is the first step that occurs!
7
Q
why is amplification necessary within the speech processor
A
ensures that the end signal can be detected and heard well by the patient
8
Q
tell me about filtering within the speech processor
A
used to divide the emphasized signal into multiple frequency bands using a filter bank, designed to mimic the natural tonotopic organization of the cochlear
-typically will use bandpass filtering, and the amount of filters corresponds with the amount of electrodes
-it is a one to one relationship with the channel and the electrode
9
Q
how many channels does each CI manufacturer offer?
A
AB: 16
cochlear: 22
MED-EL: 12
10
Q
what do we mean when we say that CI filtering relies on fourier analysis?
A
this analysis is a method that decomposes complex functions/signals into simpler components, typically as a sum of sine and cosine waves
-relating to how the cochlear is organized, so the stimulation needs to be completed in a similar way
11
Q
the cochlear implant is essentially an analyzer. what does this mean in terms of the incoming signal and hearing?
A
it takes the incoming signal and divides it into a set amount of different components
-these components are then sent to the electrodes to stimulate the appropriate nerve fibers
12
Q
what is the main goal of filtering within the speech processor
A
trying to mimic the tonotopicity of the natural cochlea
13
Q
tell me about rectification within envelope detection
A
takes anything that is negative and flops it to become positive, making it easier for the CI to process
14
Q
what is the purpose of envelope detection?
A
this gives the overarching information that is needed from each frequency band, giving a more broad spectrum of input
-the CI cannot process both spectral and temporal information so the envelope helps simplify the signal
15
Q
tell me about compression within the speech processor
A
this takes the incoming signal, compresses it to make it fit into the narrow electrical DR in order to make it suitable for stimulation
-this helps ensure that those signals of interest can be audible
16
Q
what is the purpose of compression?
A
cuts out quieter sound levels that are considered not useful and resets louder sounds to a constant level
17
Q
tell me about modulation within the speech processor?
A
it takes the amplitude that has been compressed and created a pulse that is proportional to the amplitude and frequency of each band, given to each individual electrode
18
Q
why are speech coding strategies necessary?
A
- they are the instructions
- they condense the signal
- decide what information to keep and how to deliver it
19
Q
what are the two main groups of speech coding?
A
feature extraction and waveform strategies
20
Q
what are feature extraction coding strategies?
A
this focuses on the frequencies, spectral cues and uses algorithms to help each band extract some spectral information that is used to generate the stimulus to the electrodes
-includes F0/F2, F0/F1/F2 and the mpeak strategy
21
Q
tell me about the F0/F2 strategy
A
taking the band and only extracting the F0 and F2
-developed originally for the nucleus and results were encouraging
22
Q
tell me about the F0/F1/F2 strategy
A
- taking the band and within each one they extracted the F0, F1 and F2
- this alteration showed a WRS increase however was not significant enough to yield major benefits for the patients, they still showed many errors within the consonants
23
Q
what is mpeak (multipeak) strategy?
A
included the F0/F1/F2 but added the high frequency information to be extracted as well
-created to improve the representation and perception of consonants
-showed an improvement in consonant identification and on open set sentences however still had difficulty in noise
24
Q
what are waveform coding strategies?
A
focusing on the temporal envelope to create a waveform derived from filtering the speech signal into different frequency bands. mainly focusing on the timing aspects.
-including N of M, ACE, HiRes and HDCIS
25
what is the N of M strategy?
early strategies?
with this one, every electrode has the chance of being stimulated but not everyone is stimulated at once
-the number of electrodes that is stimulated is referred to as n
-early strategies were SMSP and SPEAK
26
with N of M strategies, how are electrodes selected for stimulation
based on those that have the largest amplitude (maxima)
27
tell me about SMSP vs. SPEAK
SMSP: the first N of M in which 6 electrodes would be stimulated
SPEAK: 6-10 are selected to be stimulated
28
what is an advanced combination encoder (ACE)?
- N of M strategy that has high stimulation rates (14,400)
- activates electrodes with highest amplitude
- this is the default for manufacturers
- High ACE which has an even fast stimulation rate
29
what is continuous interleaved sampling (CIS)?
signal is sent through a bank of bandpass filters that is separated into discrete frequency bands in which the temporal envelope is extracted, then compressed and converted into interleaved electric pulses
-only activating one electrode at a time
30
what is channel interaction and how does CIS limit this?
channel interaction occurs when 1 electrode is activated and a nearby electrode becomes activated as a result of the other
-CIS only activated one electrode at a time and makes sure to put a brief pause between (but the pause is very fast we cannot even notice it)
31
what is an alteration of CIS
MPS (multiple pulsatile sampler)
-allows for doubling of stimulation rate, improving speech recognition
-this provides simultaneous stimulation where two electrodes are activated at once but they are not electrodes next to each other
32
what is high definition CIS (HDCIS)?
allows for a broader frequency range with the option to extend the lower limit to 70 Hz, used only by MED-EL
-utilizes transformation, meaning it takes the wave and shifts it so that they do not start at the same time, giving more envelope information
-gives a more complex signal with high amounts of temporal information
33
what is the difference between CIS and n of m strategies in terms of electrode stimulation?
CIS selects one electrode at a time (or 2) based on the incoming signal timing whereas n of m selects the electrodes with the largest amplitude
34
what is HiResolution (HiRes)?
what stays the same?
- higher stimulation rate
- higher cutoff frequencies for low pass filters
- 16 electrodes
- this keeps the same temporal resolution within the signal
35
what is HiRes fidelity 120?
creates virtual/phantom channels in which the place between is stimulated
36
how do HiRes fidelity 120 and HDCIS strategies create virtual channels?
HiRes creates virtual channels by current steering the voltage between electrodes whereas HDCIS creates virtual channels by using overlapping frequency filters during signal processing
37
what is fine structure processing (FSP)?
a version of CIS that extracts spectral, envelope and fine temporal structure information from the input signal
-used only with MED-EL
38
what is a coding strategy that is thought to help music appreciation?
fine structure processing (FSP)
39
what are the components of the electrode design?
electrode array, electronics, titanium housing, gold coil, magnet and complete product
40
what is the difference between the electrode vs. electrode array
electrode: the physical structure that injects current to the tissue
electrode array: the distal part that contains the electrode contacts
41
the electrode array comes in different shapes and lengths. what are some possible types?
peri modiolar, lateral and mid modiolar
42
describe how the current travels within the electrode array/electrodes
-the current travels down the wire until it reaches the area of stimulation that is intended
-this current stops moving once it hits that area of interest
-as you move towards the apex, there will be less wires as each electrode contact has its own wire
43
what are intracochlear electrode contacts?
this is where the current is injected into the neural tissue
-these come in different shapes and designs
-vital for them to be facing the correct way as we want them to go to the right neural area
44
what is monopolar stimulation?
the ground electrode is outside of the cochlea. when current is applied to the electrode in the cochlea it flows to the ground electrode.
45
what is bipolar stimulation?
the ground is within the cochlea and is another electrode on the array
-this limits the current flow between the ground and the other electrode
46
how can ME status impact implant function
active ME effusion may delay implant surgery and has been associated with reduced hearing during those episodes of OM
-this impacts the pressure and therefore disturbs the mechanics of the electrodes
47
the insertion of the electrode array can be placed in different places. why is the scala tympani preferred?
-larger diameter which avoids damage to the nerve fibers
-allows for insertion below the cochlear duct
-closer proximity to the round window
-less intracochlear trauma
-better preservation of residual hearing
-better implantation outcomes and reduced postoperative vertigo
48
how does neural activation occur, meaning how do those nerve fibers become activated
when the electrode sends out electrical current into the fluid in the cochlea, it causes voltage changes.
these changes stimulate the nearby nerve fibers, making them fire (depolarize) and send signals to the brain.
49
during CI stimulation, we use a charge-balanced biphasic pulse. why is this used?
the usage of this avoids the accumulation to much positive/negative charge that could potentially produce toxic tissue reactions
50
what are the limitations of CIs in replicating natural hearing?
spontaneous firing rate, phase locking and stochasticity
51
what is stochasticity?
this means that a single cochlear nerve fiber doesn't respond perfectly on its own, but instead, many fibers work together to encode sound information
52
why are CIs successful in providing speech intelligibility?
-much of natural speech is redundant
-much of the processing capabilities of the ear and the nervous system are redundant
53
what is the purpose of soft surgery?
refers to the techniques designed to minimize intracochlear trauma, preserve residual hearing and to optimize electrode placement within the scala tympani
54
what does soft surgery focus on?
-preventing blood and bone dust entry
-using steroids
-careful surgical site selection
-minimizing perilymph leakage and suctioning
-controlling insertion depth
55
what are some examples of early complications?
facial nerve injury, alteration of taste, infection, wound dehiscence/necrosis, early device failure, CSF leak
56
what are the three approaches to access the scala tymapni?
through basal turn cochleostomy, through the round window membrane or through the extended round window cochleostomy
57
what is a late complication?
these issues begin some time later after surgery
58
what are some examples of late complications?
extrusion of the device, displacement of electrodes, late device failure, otitis media, meningitis
59
implant patients are at a higher risk of developing meningitis. what is recommended in order to help prevent this from happening?
staying up to date with vaccines
60
what are some reasons for implant removal?
skin flap being infected, body rejecting the implant, head trauma, receiver extruding, array becoming damaged and malfunctioning of the implant device
61
how do you identify a soft failure?
occurs after evaluation by the CI team and manufacturer
-can only be confirmed by a removal examination
62
what is implant soft failure and what will it look like? symptoms?
an uncommon occurrence in which the device malfunction is suspected but cannot be proven
-declining performance, aversive symptoms such as popping or shocking and intermittent function
63
what are the two main types of telemetry tests
1. non physiological measures (impedances)
2. physiological measures (neural responses)
64
what is implant hard failure?
when a device malfunction is suspected and indeed confirmed with the available assessment tools
65
what needs to be present for a hard failure
implant integrity testing shows device malfunction AND a noticeable drop in a patients performance
66
what is telemetry?
the bi directional communication of data between the software and the implant, using radio frequency code
-tells us about the integrity of the device
67
why do we perform telemetry measures
-verify the device function
-verify the integrity and function of the auditory pathway
-obtain a baseline of neural function for tracking potential change
-assist in programming
-measure the discrimination of different sitmuli
-measure the plasticity of the auditory system
68
what is the clinical usage for impedance?
-identification of electrode failures
-verification of voltage compliance
-monitoring electrode function over time
-evaluates intraoperative to postoperative changes
-monitors changes across follow up visits
69
what is electrode impedance?
measure of the opposition to electrical current flow across an electrode when a certain voltage is applied
-confirms that electrodes are functioning properly
70
what is an open circuit?
incomplete path for current to flow, a discontinuous circuit
-infinite resistance, prohibiting the flow of current
-anything greater than 30
71
what is a short circuit?
low resistance between two points in a circuit that differ in potential which are separated by higher resistance resulting in an increase in current flow
-anything less than 1
72
how to manage both open and short circuits
-would want to disable any electrode
-re evaluate after a period of implant usage
-if they resolve they can be reactivated IF they remain normal over several visits
-if it remains intermittent, it should remain disabled
73
what is voltage compliance?
software specifies a fixed amount of current
if voltage amount that agrees with the battery = in compliance
can not exceed this level or it is out of compliance
74
what is a partial short circuit?
characterized by relatively low resistance resulting in increased current flow, but less so than for a true short circuit
-impedances decreasing over time and those impedances changes relative to the other electrodes
75
how do you manage a partial short circuit?
may or may not want to disable depending on the extent
-would not want to turn it off unless the patient is complaining about anything
76
how are open circuits caused? short circuits? partial short circuits?
open: broken electrode contact/lead wire/anomalies/air bubbles
short: electrode contacts touching
partial short: small tears or fractures
77
even though we may get normal electrode impedances, this does not mean that everything is working well. why is that?
impedances do not indicate if the electrode contact is within the cochlea or not as it only indicates how the electrical current flows across the electrode contact to the surrounding tissues
78
what happens if a patient is using a map with electrodes that are out of compliance
-speech recognition and sound quality may be reduced
-loudness may be unbalanced across the electrode array
-they may experience non-auditory effects
79
why are monopolar configurations poor with detecting short circuits?
this coupling options assesses one electrode on the array to an extra cochlear electrode so therefore these short circuits will not be identified as it is not occurring with two electrodes on the array
80
what is the expected impedance change over time?
impedances will change naturally over time, with them being the lowest at the time of surgery due to the medium being perilymph
-and within those first few weeks they increase due to fibrous tissue encapsulation
81
how can abnormal impedances impact the patient?
compromises sound quality, produces nonauditory sensations, poor speech recognition, sudden changes in loudness and potential discomfort
82
what is electrode conditioning?
this allows for the presentation of low levels currents to each electrode to remove air bubbles, protein buildup and other aspects
-only within AB devices
83
what programming sotftware is used by each manufacturer?
MED-EL with maestro
AB with target CI
cochlear americas with custom sound pro
84
what is electrical dynamic range?
the difference b/w the patients T & M levels
different for each electrode bc each threshold is different
85
explain the components of the input dynamic range within the electrical DR. whats the default?
typically the default of the input DR is 40-60 dB
-lower end is the threshold
-upper end is the maximum stimulation
86
what is frequency allocation
the controls how frequencies are delivered across active channels
87
how do changes in stimulation rate (number of pulses delivered to each electrode) impact the signal
higher rates can result in an increase in loudness due to temporal summation
88
what is the importance in selecting the correct magnet strength?
this prevents the coil from falling off of the head and if there is too much adherence this may compromise circulation to the skin underneath
89
how can magnet strength vary for children vs. males vs. older adults?
children and elderly women generally need weaker magnets due to thin skin whereas middle aged men tend to need stronger magnets due to thicker skin
90
differentiate a map vs. a program
map: refers to the process of adjusting the electrical stimulation parameters for the implant
program: the settings that all occur within the speech processor
91
what are the primary goals of programming?
-restore audibility for a wide range of speech sounds
-set stim. levels to optimize identification of speech sounds
-ensure normal loudness perception speech/environment
-restore normal loudness perception for speech/environment
92
what are minimum stimulation levels?
least amount of stimulation a recipient can detect when electrical signal are delivered to individual electrodes
-T levels, THR
93
how to find the T levels?
if that doesnt work what are the traditional methods?
these are based on ascending paths to ensure audibility
-we can so so by traditional threshold measurement techniques, count the beeps, loudness scaling or threshold estimation
94
how can inaccurate T levels impact the patient?
-too low may result in not adequate audibility of low level sounds
-too high may result in excessive ambient noise
95
what are upper stimulation levels?
upper limit of electrical stimulation, the loudest that they can tolerate
-M, MCL or C levels
96
how to find M levels?
-psychophysical loudness scaling, aiming for comfortable but loud
-global increase in upper stimulation levels while listening to speech based on patients' feedback
97
how can inaccurate M levels impact the patient?
if too high it can lead to overstimulation which causes discomfort, poor sound recognition, aversive reaction to CI and poor overall outcomes
98
tell me about loudness balancing and how it optimizes the map
aims to ensure equal loudness at upper stimulation levels to help optimize speech recognition and sound quality
-without this balanced loudness, speech recognition can be impacted as one electrode may be dominating the overall signal
99
how to conduct loudness balancing?
tell the patient that they will hear two tones and we need them to tell us if the two tones are the same loudness or not
-they need to avoid paying attention to the pitch and only focus on the loudness
100
tell me about sweeping and how it optimizes the map
the sequential presentation of the programming stimulus across all electrode contacts in the array, starting from the special end and ending at the base
-this confirms equal loudness across all channels
101
how to conduct sweeping?
tell the patient that they will hear various sounds that are going to differ in pitch, their job is to identify if any of the electrodes are different loudness levels
-we go between one and the next working our way down
-then can go and play at every electrode on the array
102
what is an optimization approach that can only be conducted within MED-EL?
anatomy based fitting
-this involves reducing spectral mismatch through imaging and using that information to create the map
103
tell me about optimization vs. maintenance phase
optimization: 1 to 3 months post surgery and is focused on rehabilitation tools and wearing the device as much as possible
maintenance: 3+ months post surgery focusing on maximizing device usage
104
if our patient is showing non-auditory stimulation, what can we do? CI
-decrease the upper stimulation level
-if we continue to decrease it to a level that is too soft, then increase the pulse width (improving loudness perception)
-if we continued to drop it and was still seeing it, then turn off the electrode (if we find two electrodes like this)
-activate focus stimulation (taking it from monopolar to bipolar)
105
how to know if the patient is ready to move from the optimization phase to the maintenance phase?
-SF thresholds better than 30 dB
-10+ hours per day with data logs
-post operative CNC scores in the implanted ear of around 56% or better OR patients score in the implanted ear have improved by at least 20%
106
what do we mean by non-auditory stimulation in CI patients?
signs such as facial stimulation when levels continue to be increased
107
within pediatric CI fittings, what are the three responses we may see?
-positive
-neutral
-upset/distressed (often due to the sudden exposure to a new sensory input, this is acceptable as long as it is not painful)
108
What is the importance of full time device usage? also why is this important in kids?
early auditory input requires sound exposure to develop those pathways
-missing input during the critical period can cause irreversible delays in auditory and spoken language development
109
what are the techniques for setting upper levels?
-loudness scaling
-global adjustments in live speech
110
what are the techniques for setting T levels in pediatrics?
same ascending/descending method used for adults is also appropriate
-larger step sizes can help when working with children with limited attention spans
-using interpolation to estimate T levels on unmeasured channels
111
what are signs of overstimulation in children?
-holding breath
-exhibiting facial expressions of mild concern
-looking to caregiver for reassurance
-tensing or stiffening of the body
-playing more actively
-wringing hand, clothes or toes
-producing blinks in response to the stimulus
112
in children, why should we avoid routine increase in upper stimulation levels?
MAP stability is important when the child is making age-appropriate progress, a stable MAP supports consistent access to sound, especially during early developmental years
113
when should MAP adjustments occur in pediatrics?
with clear evidence from
-behavioral audiologic assessments
-speech and language assessments
-auditory skills assessment
-functional performance questionnaires
114
what are the recommended follow ups for pediatric CIs?
during first year: more often
after the first year: depends on the child's progress (every 3 months if they are not reliable in reporting sound quality or every 6-12 months if the child provides consistent feedback)
115
what are the 3 objective measures?
ERST, EABR, ECAP
116
what are electrically evoked stapedial reflex threshold (ESRT)?
measuring the contraction of the stapedial muscle in response to intensive electrical stimulation from the CI
-we are evoking it from the implant
-preferable method for setting M levels in children
117
what is the procedure for recording ESRT?
- immittance probe on contralateral side of the implant
- perform a tymp then go to acoustic reflex decay
- at the same time present programming stimulus to the implant ear in an asceding manner
- when the stimulus is loud/strong enough to elicit a reflex, a time locked decrease in admittance will be observed
- once recorded in a sufficient number of electrodes across the array, the M levels can be set toe ESRT levels
118
upper stimulation levels should typically ___ the ESRT threshold
not exceed
119
what is the clinical utility for ESRTs?
predicting upper stimulation levels
-typically within 9 CUs of the stimulation levels
-M levels 5 to 10% below ESRT for AB
-M levels 10 to 15 beloe ESRT for Cochlear
-M levels at or near ESRT for MED-EL
120
what are the limitations of ESRTs?
-ME anomalies may interfere with obtaining a response
- may be problematic to measure in bilaterally implanted pt's
121
what are electrically evoked auditory brainstem response (EABR)?
a neurophysiological test measuring auditory brainstem activity in response to electrical stimulation from a CI
-reflects synchronous firing of neurons in the brainstem
122
what is the difference of EABR vs. ABR
-stimulation via CI
-often only wave 3 and 5 are visible
-will not see changes in latencies with changes in intensity
-latencies typically occur earlier with the EABR
123
what is the procedure for EABR?
The cochlear implant sends sound through software-controlled stimulation, while EEG electrodes on the head record the brain’s response. A trigger signal marks when the sound starts so the system knows when to look for the response.
124
what is the interpretation of the EABR?
wave 3 around 2 ms, wave 5 around 4 ms
125
what are electrically evoked compound action potential (ECAP)?
shows the auditory nerve response to electrical stimulation from the cochlear implant. It reflects activity from the nerve fibers near the implant.
You’ll see:
- A negative peak at around 0.2–0.4 ms
- Followed by a positive peak at around 0.6–0.8 ms
126
ECAP is also known as …
-NRI in AB
-NRT in cochlear
-ART in MED-EL
127
what is the procedure for ECAP?
-signal is delivered to a recording amplifier that is located in the electronics package
-amplified signal is then delivered from the recoding amplifier to the DSP where it gets converted to a digital code to a electromagnetic signal that gets delivered from the implant to the sound processor
-signal is then delivered to the computer where it is processed, analyzed and displayed
128
what are the limitations of measuring the ECAP?
-current source saturation
-poor reference contact
-stimulation artifact
129
what are the 3 approaches to reduce artifact within the ECAP?
-forward masking
-alternating polarity
-scaled template subtraction reduction
130
what are the 3 methods for measuring the ECAP?
amplitude growth sequence, recovery sequence, and spread of excitation
131
what is amplitude growth sequence (AGS)?
we want to see how the response grows as the stimulation gets stronger. play a series of pulses through ONE electode, each stronger than the last. After each pulse measure the ECAP.
132
what is recovery sequence?
we want to see how long recovery takes. we play 2 pulses on after another to stimulate the nerve, then measure the ECAP.
133
what is the spread of excitation (SOE)?
helps us see which electrodes have poor activation. 1 electrode sends out a pulse and we see which regions respond.
134
what is the relationship of the ECAP measurement and stimulation levels?
thresholds
ECAP thresholds almost always occur above T levels and they tend to occur in the upper portion of the behavioral dynamic range
-more likely to exceed the M levels for faster stimulation rates
135
what is an auditory brainstem implant (ABI)?
surgically implanted device that provides auditory sensation to individuals who cannot benefit from a CI
136
distinguish an ABI vs. CI
-electrodes are placed differently
-electrode placement is challenging, so we rely on electrophysiological results
-activation is more intense
-needing to anticipate the non auditory sensation
-more presence within the room for activation
-needing to do each electrode with pitch ranking
137
what are the FDA indications for an ABI?
-12+ that are diagnosed with NF2
-rendered deaf due to bilateral resection of neurofibromas of the nerve
138
there are no acceptations for pediatric patients without the diagnosis of NF2 but …
-there are clinical trials that they can be enrolled in, resulting around off label considerations
-children 18 months to 5 years with congenital cochlea nerve aplasia and/or cochlear aplasia, bilateral profound HL and strong family support with a commitment to postoperative habilitation
139
what are the two surgery approaches for ABI?
translabyrinthine approach and retrosigmoid approach
140
what is a translabyrinthine approach?
involves removal of the mastoid bone behind the auricle as well as the SCC of the inner ear
-a good approach as it gives good visualization
-however, this eliminates any possibility of preserving residual hearing
141
what is a retrosigmoid approach?
It’s a surgical method where an incision is made behind the ear to reach the brainstem and cerebellum.
- it gives good access to the hearing nerve (CN 8).
- but it needs the cerebellum to be moved, and it doesn’t fully show the facial nerve (CN 7).
142
what are electrode array placement challenges for an ABI?
-no clear landmarks
-anatomical variations
-removal of large tumors can distort surrounding anatomy
-full surface of cochlear nucleus is not visible during surgery
143
why is intraoperative electrophysiology critical to achieve optimal electrode placement (ABI)?
given the limited visibility and anatomical variability during ABI surgery, visual guidance alone is not sufficient for accurate electrode placement
144
tell me about the usage of EABR during intraoperative monitoring and ABI surgery
confirming that stimulation from the electrode array activates the auditory brainstem pathway
-helps to optimize electrode placement by confirming effective stimulation of the cochlear nucleus
145
during mapping, why is the ABI more complex and time consuming when compared to a CI
-presence of non auditory sensations
-more central focus of stimulation
-uncertainty and irregularity of tonotopic stimulation
-potential central disease from NF-2
146
what to do within an ABI fitting if non auditory sensations occur?
-if minor you can reduce current level, increase pulse width, change electrode coupling mode or can reduce pulse rate
-if these do not help, electrode should be disabled
147
what are factors that influence ABI outcome?
-placement of the device
-anatomy of the patient/CN
-motivation to hear
-psychological readiness
-anatomical status
-acceptance of device limitations
-family and support system
-commitment to rehabilitation
Year 2 Courses
flashcards
Decks in class (20)
# Cards
-
Pharm Quiz 174
-
Amp 2 Test 147
-
Amp 2 Test 214
-
CAPD Quiz 1108
-
CAPD Midterm82
-
CAPD Final Deck142
-
Tinnitus Midterm124
-
Tinnitus Final100
-
Counseling Midterm34
-
Practice Development Midterm79
-
Aural Rehab Midterm74
-
Aural Rehab Final77
-
Vestib 1 Midterm125
-
Vestib 1 Final95
-
Implantables Midterm140
-
Implantables Final147
-
Evoked Responses Quiz Overview90
-
Evoked Responses Quiz Shortened77
-
Evoked Responses Midterm69
-
Evoked Responses Final146
