Transcript Dissertation Proposal - University of Wisconsin–Madison

WAISMAN
CENTER
Binaural Hearing and
Speech Laboratory
Speech Discrimination and Spatial Hearing
in Toddlers with Cochlear Implants
Christi Hess, Ph.D CCC-SLP
CI Day with the Experts
May 31, 2014
Where we are
 Access to sound
 Age of implantation
 Bilateral cochlear
implants (BiCIs)
Where we want to be
Understanding the impact of early BiCIs on:
 Fine-tuned auditory abilities
?
 Spatial hearing
?
 Language development
?
ThisReaching
is what we
do now
forcan
Sound
Litovsky, Ehlers, Hess & Harris, 2013
Stimuli
Voicing
Place
Manner
Easy Value (ms)
Hard Value (ms)
BEE
Voiced
Bilabial
Stop
5 ms
15 ms
PEA
Voiceless
Bilabial
Stop
45 ms
35 ms
KEY
Voiceless
Velar
Stop
45 ms
N/A
100
/b/
90
/p/
Observations
80
70
60
50
40
30
20
10
0
-50
-40
-30
-20
-10
0
10
20
30
Voice Onset Time
40
50
60
70
80
Participants
13 toddlers who use BiCIs:
 Mean age: 32.4 mo. (8 Male, 5 Female)
 At least 1 year of experience with CI1 at visit
 Native English speaker
 Primary communication mode = oral/aural
 No diagnosed developmental disabilities
 Did not control for: age of implant, device manufacturer, bilateral exp.
13 toddlers with NH:
 Mean age: 31.8 mo. (8 Male, 5 Female)
 No history of hearing loss, ear infections, or other developmental delays
 Tymps and hearing screening performed
Procedure
Live-Voice Familiarization
Training (4/5 Criterion)
Pea/Key vs. Bye
Testing: (4 contrasts; 18 trials each)
Place
Place+Voicing Voicing(hard)
Place
Place+Voicing
Voicing(easy)
Voicing(easy)
Voicing(hard)
NH are more accurate than BiCI
*
p=0.03
*
p=0.04
*
*
p=0.001
p=0.002
*
p=0.002
*
p=0.002
*
r2=0.32
r2=0.08
r2=0.005
r2=0.07
Quiet = IDEAL!
But, unrealistic
Location Cues
-
=
Spatial Hearing
CRISP
Garadat & Litovsky, 2007
Testing Conditions
Quiet
= Target (Male)
= Masker (2 Females)
Collocated
Separated
CRISP
Garadat & Litovsky, 2007
Stimuli
 Target: male-talker, adaptive (starting 60 dB SPL)
 Masker: 2 female talkers, fixed (55 dB SPL)
Garadat & Litovsky, 2007
Procedure
Familiarization with target words
Training (4 trials)
Quiet and Collocated conditions
Testing: 4-AFC task (repeated 2 times for each condition)
Quiet
Collocated
Collocated
Quiet
Separated
Collocated
Separated
Quiet
Quiet
Separated
Collocated
Speech Reception Threshold (SRT)
80% correct criterion,
calculated using a 3-down/1-up procedure
Garadat & Litovsky, 2007
Better SRTs when masker is in a
different location than the target
p=0.001
p=0.02
**
**
*
*
p<0.001
p<0.001
*
p<0.001
Collocated SRT
Separated SRT
-
-
= + SRM
= 0 SRM
=
Spatial Release from Masking (SRM)
More bilateral listening experience =
greater benefit from spatial separation
BiCI BiCIBiCI BiCI
BiCI
(2-3)(5-7)(5-7) (7-9)
(7-9)
NH
NH NH NH NH Adult
(2-3)
(7-9)
(5-7) (5-7)(7-9)
Misurelli & Litovsky, 2012
Where
we want
to be
Where
we are
Understanding the impact of early BiCIs on:
 Fine-tuned auditory abilities
 Spatial hearing
 Language development
?
What does this mean?
Speech Language Pathologists
Auditory Verbal Therapists
Parents
Educators
Audiologists
Thank you!
• Members of the BHSL who
have helped with data
collection and analysis
• Families who travel to
participate
• My family and friends for
all of their support
References
•
•
•
•
Garadat, S., & Litovsky, R.Y. (2007). Speech Intelligibility in Free Field: Spatial Unmasking in Preschool
Children. J. Acoust. Soc. Amer. 121: 1047-1055.
Grieco-Calub, T., Litovsky, R.Y., & Werner, L.A. (2008). Using the observer-based psychophysical
procedure to assess localization acuity in toddlers who use bilateral cochlear implants. Invited paper in
special issue of Otology and Neurology. 29(2):235-239.
Litovsky, R.Y., Ehlers, E., Hess, C., & Harris, S. (2013). Reaching for sound measures: An ecologically
valid estimate of spatial hearing in 2- to 3-year-old children with bilateral cochlear implants. Otol. &
Neurotol. 34(3): 429-435.
Misurelli, S.M., & Litovsky, R.Y. (2012). Spatial release from masking in children with normal hearing and
with bilateral cochlear implants: Effect of interferer asymmetry. J. Acoust. Soc. Am. 132(1): 380-391.