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Bimodal Hearing: A Hearing Aid In Conjunction With A Cochlear Implant
Questions?
For any questions during this broadcast, please send an email to:
teresa mcevoy@boystown org
[email protected]
Questions will be answered at the end of the presentation.
Jeff Simmons, M.A., CCC‐A Audiologist, Cochlear Implant Clinical Coordinator
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Bimodal Hearing: A Hearing Aid In Conjunction With A Cochlear Implant
Bimodal Hearing: A Hearing Aid In Conjunction With A Cochlear Implant
Jeff Simmons, M.A., CCC‐A Audiologist, Cochlear Implant Clinical Coordinator
Acoustic Auditory Pathway
Cochlear Implant Function
Headpiece
ICS
Speech Processor
Electrode Array
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Bimodal Hearing: A Hearing Aid In Conjunction With A Cochlear Implant
Cochlear Implant Candidacy
• FDA criteria first set in 1985 for adults
• Severe to profound hearing loss
• Limited benefit from amplification
– Aided speech perception for sentences Aided speech perception for sentences
– <40 to 50% in implanted ear
– <40 to 60% in “best aided condition”
• Assume loss of residual hearing
Today’s CI Recipients
• Different from earlier implant candidates? • Expanding criteria
– Improved outcomes with CIs Improved outcomes with CIs
– more patients implanted with more residual hearing in the non‐implanted ear.
• “Off Label”
Changing Candidacy
Novak et al., 2007
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Bimodal Hearing: A Hearing Aid In Conjunction With A Cochlear Implant
Unilateral Or Bilateral?
Need For Bimodal Stimulation?
• Majority of CI recipients have unilateral implant
• Consideration: Residual hearing in non‐implanted
non
implanted ear
ear
• Bimodal Stimulation
– CI (electrical stimulation) in one ear – HA (acoustic stimulation) is used in the contralateral ear
CI & HA Mutually Exclusive?
• Common wisdom…
– Two different kinds of signals
– Hearing aid as a crutch?
• Experience with early implant users
– Dooley et al., 1993
l
l
– Lack of control of two independent devices
• Pitch or loudness mismatch
• Binaural interference
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Bimodal Hearing: A Hearing Aid In Conjunction With A Cochlear Implant
Why Bilateral Stimulation?
• Auditory system is designed to work with two sources of auditory input
• How long have binaural HAs been standard of care?
• Binaural advantage
i
l d
– Redundancy/summation
– Head shadow
– Binaural squelch
Benefits Of Binaural Hearing
• Binaural = input from both ears and coordination by the nervous system
• Sound localization • Improved speech perception in quiet and/or noise
• Less listening effort
• “Naturalness” of sound
Why Does One Need Two?
• CI does not restore normal hearing
• Impact of unilateral deafness
– Educational difficulties 10 x more likely
– Increased chance of behavioral problems Increased chance of behavioral problems
– Risk for speech‐language delays
– Difficulty hearing in noise and tracking conversation in groups
– Poor localization abilities
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Bimodal Hearing: A Hearing Aid In Conjunction With A Cochlear Implant
Neuro‐Biological Effects
• Auditory deprivation effects
– Retrograde degeneration
– Auditory neurons and cortex
• Effects on binaural pathways
Effects on binaural pathways
– More extensive morphological changes than for bilateral loss
– Imbalance in structures that receive binaural projections Bimodal Stimulation
CI And Contralateral HA
• Growing body of research supports benefit of combining acoustic and electric stim
• Most listeners can integrate the two
Most listeners can integrate the two
– Potential to restore some binaural auditory functions
– Even if hearing aid has not been used for a longer period of time
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Bimodal Hearing: A Hearing Aid In Conjunction With A Cochlear Implant
Bimodal Stim vs. One CI Only
• If recipient has residual hearing in non‐implant ear…
– Improved speech understanding in noise
– Improved localization ability
– Less listening effort
– More “natural” sound quality
– Improved “distinctiveness of voices”
– Music perception/enjoyment/appreciation
Bimodal Stim & Localization
• Many subjects demonstrate improved horizontal localization ability in the bimodal condition vs. CI alone condition
• High degree of variability across individuals
Benefits Of Low Frequencies
• Is there a minimum amount of residual hearing needed to benefit from CI + HA?
• Enough residual hearing for speech p
perception with HA alone is NOT necessary
p
y
• Greatest increment of benefit from adding frequencies below 125 to 300 Hz
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Bimodal Hearing: A Hearing Aid In Conjunction With A Cochlear Implant
Benefits Of Low‐Frequencies
• Low‐freq information is not well transmitted by cochlear implants
• “Complementarity” of acoustic signal
– F0 and F1
F0 and F1
– Pitch cues & voice segregation
– Formant transitions
– Information about voicing and manner Low Frequency Acoustic Information
Zhang et al., 2010
Buchner et al., 2009
Typical Pattern Of Test Findings
Monosyllable % Correct
*
• Firszt, Reeder, & Skinner (2008)
• Speech perception ‐
y
monosyllable words
• CI + HA is better than CI or HA alone
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Bimodal Hearing: A Hearing Aid In Conjunction With A Cochlear Implant
Bimodal Studies ‐ Speech Perception
• Gifford et al. (2007)
– 11 adults with significant residual
significant residual low‐frequency hearing
– Bimodal benefits in quiet and noise
Cost Effectiveness Rationale
• Compared to bilateral CI, it is less expensive & less invasive
• Is bimodal function as good as function with binaural CI?
function with binaural CI? – Schafer et al., 2007
• Limited resources scenario: provide unilateral CIs to more patients vs. bilateral CIs to fewer patients.
Bimodal Trend
Growing percentage of CI recipients using a hearing aid in the non‐
implant ear
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Bimodal Hearing: A Hearing Aid In Conjunction With A Cochlear Implant
Bimodal Stimulation
• Most CI recipients can integrate electric and acoustic input
• Some kind of device should be considered for the second ear of all unilateral implant recipients • Results will obviously be more limited with minimal residual hearing
Bimodal Protocol?
• Special considerations?
• Independent or interdependent?
• No widely accepted protocol or practices
• Some published recommendations
bl h d
d
– Ching et al., 2004 – Mok et al., 2006
– Ullauri et al., 2007
– Kielman et al., 2010
Ching Et Al.(2004) Procedure
• 2‐step procedure:
– Paired comparisons between frequency responses to determine preferred one for speech • NAL‐RP
• More low‐freq gain
• Less low‐freq gain
– Loudness balancing procedure
• Adjust overall HA gain • Compare HA to CI loudness 10
Bimodal Hearing: A Hearing Aid In Conjunction With A Cochlear Implant
Alternative Frequency Response
Gain by Frequency
250 Hz
Low Freq
Boost
NAL
Low Freq
Cut
500 Hz
1000 Hz
2000 Hz
4000 Hz
+7 dB
+4 dB
+0 dB
-6 dB
-12 dB
NAL gain
NAL gain
NAL gain
NAL gain
NAL gain
-11 dB
-5 dB
-1 dB
+5 dB
+8 dB
http://www.nal.gov.au/pdf/BimodalHearing-A-Guide-to-Fitting.pdf
HA Fitting Considerations
• Ching et al. (2004): – greater bimodal benefit (speech perception and localization) when HAs were fine‐tuned or “optimized”
– Start with NAL‐RP and compare to alternate frequency responses
– balance loudness for live speech
100
90
80
70
60
50
40
30
20
10
0
In noise
In quiet
Desired Sensation Level (DSL)
• Focuses on audibility of speech signal
• Allows visualization of audibility low‐
frequency component
• Does not require input from patient
Does not require input from patient
• Has not been directly compared to NAL‐RP in study with bimodal users
• Keilmann et al., 2010; Park et al., 2012
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Bimodal Hearing: A Hearing Aid In Conjunction With A Cochlear Implant
Aided Audibility
Aided Audibility
• No audibility for p
portion of LTASS above 1.1 to 1.5 kHz
Keilmann Et Al. (2010) Procedure
• Hearing aid set with DSL prescriptive method
• CI and HA optimized separately, th t t d t th
then tested together
– Speech audiometry
– Loudness scaling
• Procedure not well‐detailed
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Bimodal Hearing: A Hearing Aid In Conjunction With A Cochlear Implant
Bimodal Fitting Procedure
• Differing procedures are in use
• Most studies of bimodal stimulation demonstrate a benefit
Loudness balancing may be difficult
• Loudness balancing may be difficult to perform • Further study is needed to determine if there is a “best” procedure
Bimodal Stimulation
Case Example: Adult Patient
Case Example: Background
•
•
•
•
Female
First seen at age 53
Progressive loss, unknown etiology
Explored multiple options
– Conventional amplification
C
ti
l
lifi ti
– Frequency compression
– FM
• Difficulty communicating well enough to perform her job in sales
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Bimodal Hearing: A Hearing Aid In Conjunction With A Cochlear Implant
Audiometric History
Audiometric History
Aided Speech Perception
Scores by Test Condition
Tests Administered Right Aid
CNC Words
Words:
Phonemes:
HINT Sentences
Left Aid
Binaural Aids
DNT
DNT
28%
57%
45%
66%
72%
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Bimodal Hearing: A Hearing Aid In Conjunction With A Cochlear Implant
1 Month Post‐Op
Thresholds: CI & Left Ear
Speech Audibility
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Bimodal Hearing: A Hearing Aid In Conjunction With A Cochlear Implant
Speech Audibility
Speech Audibility
Speech Audibility
Audibility of speech spectrum up to ≈1800 Hz
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Bimodal Hearing: A Hearing Aid In Conjunction With A Cochlear Implant
Pre‐CI vs. Post‐CI
100
90
80
70
60
50
40
30
20
10
0
HA
Po
HA
CN
C
stCI
CN
C
HI
NT
Po
stCI
HI
NT
Left
Right *
Binaural
100
90
80
70
60
50
40
30
20
10
0
R)
es
SN
dB
Does the hearing aid help?
Bi
o
(+
10
R)
SN
dB
(+
5
Bi
o
A
Z
Z
A
H
IN
T
T
IN
Se
nt
en
c
ce
te
n
Se
n
on
em
es
H
C
NC
Ph
NC
C
s
HA
CI
CI + HA
W
or
ds
Perccent Correct
Current Speech Perception
Patient Comments
• “I don’t even ask for assistive listening devices any longer. It just doesn’t occur to me like it used to…”
• “I need both the CI and the hearing aid for the best clarity of speech…”
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Bimodal Hearing: A Hearing Aid In Conjunction With A Cochlear Implant
Bimodal Stimulation
Case Example: Pediatric Patient
Background
•
•
•
•
•
•
Female, first seen at age 3;9
Family primarily Spanish speaking
Concerns for unintelligible speech
Hx of 2 previous audiograms WNL
Hx of 2 previous audiograms WNL
DPOAEs absent 1500‐8000 Hz, bilaterally
Initial ABR indicated severe to profound bilateral hearing loss
Behavioral Audiogram
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Bimodal Hearing: A Hearing Aid In Conjunction With A Cochlear Implant
Amplification Fitting
No high-frequency
audibility
Based on “estimated”
thresholds
CI Candidacy Evaluation
No
Response
CI Right at Age 4:6
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Bimodal Hearing: A Hearing Aid In Conjunction With A Cochlear Implant
Benefit from Bimodal Stim?
Aided Audibility
Aided Audibility
• Audibility of LTASS up to above 1.1 ‐ 1.5 kHz
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Bimodal Hearing: A Hearing Aid In Conjunction With A Cochlear Implant
CI and HA No
Response
for Left
First Year Post‐Op CI
• Consistent use of CI and HA
• Subjectively performs better bimodally than CI alone
• Total Communication program in school
Total Communication program in school
• English skills surpassing Spanish
• Progress in auditory skills per ESP
Auditory Skills Development
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Bimodal Hearing: A Hearing Aid In Conjunction With A Cochlear Implant
Summary
• Cochlear implants do have application in patients with residual hearing
• Acoustic signal from a hearing aid can be used to supplement the electrical signal pp
g
from a cochlear implant
• Bimodal benefits may show up best in noisy listening situations
Summary
• Subjects report on “real‐life” advantages (even those with no measurable speech perception benefit).
• HAs may need to be adjusted to optimize performance.
performance
• Bimodal benefits may be immediate or may evolve over time. • Even patients who have not used amplification for a few years may receive bimodal benefit.
Summary
• Research suggests that bimodal fitting should be considered for patients with CIs who have useable residual hearing in the non‐implanted ear.
• Bimodal stimulation is recommended for patients with residual hearing and good HA performance in non‐CI ear, those who want to restore binaural hearing and all young children.
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Bimodal Hearing: A Hearing Aid In Conjunction With A Cochlear Implant
References
• Büchner A, Schüssler M, Battmer RD, et al. (2009). Impact of low‐frequency hearing. Audiology & Neurotology, 14(suppl 1), 8‐13.
• Ching TY, Hill M, Dillon H, et al. (2004). Fitting and g
g
p
evaluating a hearing aid for recipients of a unilateral cochlear implant: The NAL approach. The Hearing Review, 11(7), 14‐22, 58.
• Dooley GJ, Blamey PH, Seligman PM, et al. (1993). Combined electrical and acoustical stimulation using a bimodal prosthesis. Archives of Otolaryngology Head and Neck Surgery, 119, 55‐59.
References
• Firszt JB, Reeder RM, Skinner MW (2008). Restoring hearing symmetry with two cochlear implants or one cochlear implant and a contralateral hearing aid. Journal of Rehabilitation Research and Development, 45, 749‐768.
• Gifford RH, Dorman MF, McKarns SA, et al. (2007). Combined electric and contralateral acoustic hearing:
Combined electric and contralateral acoustic hearing: Word and sentence recognition with bimodal hearing. Journal of Speech, Language, and Hearing Research, 50, 835‐843. • Keilmann, AM, Bohnert AM, Gosepath J, et al. (2009). Cochlear implant and hearing aid: A new approach to optimizing the fitting in this bimodal situation. European Archives of Otorhinolaryngology, 266, 1879‐1884.
References
• Mok M, Grayden D, Dowell RC, et al. (2006). Speech perception for adults who use hearing aids in conjunctio with cochlear implants in opposite ears. Journal of Speech, Language, and Hearing Research, 49, 338‐351.
• Novak MA, Black JM, Koch DB. (2007). Standard cochlear implantation of adults with residual low‐frequency
implantation of adults with residual low
frequency hearing: hearing:
Implications for combined electro‐acoustic stimulation. Otology & Neurotology, 28, 609‐614.
• Park LR, Teagle HFB, Buss E, et al. (2012). Effects of frequency compression hearing aids for unilaterally implanted children with acoustically amplified residual hearing in the nonimplanted ear. Ear & Hearing. doi: 10.1097/AUD.0b013e31824a3b97 23
Bimodal Hearing: A Hearing Aid In Conjunction With A Cochlear Implant
References
• Ullauri A, Crofts H, Wilson K, at al. (2007). Bimodal benefits of cochlear implant and hearing aid (on the non‐implanted ear): A pilot study to develop a protocol and test battery. Cochlear Implants International, 8(1), 29‐37.
• Zhang T, Dorman MF, Spahr AJ. (2010). Informatio nfrom the voice fundamental frequency (F0) region accounts for the majority of the benefit when acoustic stimulation is added to electric stimulation. Ear & Hearing, 31, 63‐69.
Jeffrey L. Simmons, M.A., CCC‐A
Boys Town National Research Hospital
555 North 30th Street
555 North 30
Omaha, Nebraska 68131
[email protected]
Jeff Simmons, M.A., Audiologist, Cochlear Implant Clinical Coordinator
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Bimodal Hearing: A Hearing Aid In Conjunction With A Cochlear Implant
A production of the Lied Learning & Technology Center at Boys Town National Research Hospital
555 North 30th Street Omaha, NE 68131
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