the intersection of hearing science and hearing technology brent edwards, ph.d. executive director...
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The Intersection of Hearing ScienceAnd Hearing Technology
Brent Edwards, Ph.D.Executive Director
Starkey Hearing Research CenterBerkeley, CA
The Current State of Hearing Aids
•91% have Digital Signal Processing
MIPS versus Year for 1 mW System Power
0
5
10
15
20
25
1999 2000 2001 2002 2003 2004 2005 2006 2007 2008
Year
MIP
S
Digital Tech
•Multiband compression•Feedback cancellation
•Noise reduction•Environment Classification
•Datalogging•Automatic features
•Echo reduction
Digital Tech
•Multiband compression•Feedback cancellation
•Noise reduction•Environment Classification
•Datalogging•Automatic features
•Echo reduction
Other Technologies
•Directional Microphones
•Wireless connectivity•Design innovation
•Nanotech applications•Rechargeable batteries
Hybrid Electric-Acoustic Devices
Med-ElMed-El
Digital Tech
•Multiband compression•Feedback cancellation
•Noise reduction•Environment Classification
•Datalogging•Automatic features
•Echo reduction
Other Technologies
•Directional Microphones
•Wireless connectivity•Design innovation
•Nanotech applications•Rechargeable batteries
Change Blindness
Perceptual Science will lead the development of the next hearing
aid advances
Starkey Hearing Research Center
•Created in 2004 as a Translational Research Center
•Academic-type scientific environment for industry-related
research
Focus research on:
•Speech communication•Access to environmental and
other non-speech sounds•Spatial hearing
•Selective attentionStuart GatehouseStuart Gatehouse
•Loss of environmental awareness leads to stress and anxiety.•Listening is not passive.•Relaxing is hard to do.
•Loss of environmental awareness leads to stress and anxiety.•Listening is not passive.•Relaxing is hard to do.
Portis, 2005Portis, 2005
Hearing loss can cause memory problems and other cognitive deficits
McCoy et al., 2005McCoy et al., 2005
Pre-attentiveobject feature
formation
•harmonicity•timbre•localization•common modulation
Selectiveattention
Cocktail Party Phenomenon
Pre-attentiveobject feature
formation
•harmonicity•timbre•localization•common modulation
Selectiveattention
Cocktail Party Phenomenon
Vowel SegregationHumans can hear two concurrent
vowels when pitches differ
/i/ /a/ /i,a/Summerfield and Assman, 1991Summerfield and Assman, 1991
/i/ /a/ /i,a/
i: f0=100 Hza: f0=100 Hz
Vowel SegregationHumans can hear two concurrent
vowels when pitches differSummerfield and Assman, 1991Summerfield and Assman, 1991
/i/ /a/ /i,a/
i: f0=100 Hza: f0=126 Hz
Vowel SegregationHumans can hear two concurrent
vowels when pitches differSummerfield and Assman, 1991Summerfield and Assman, 1991
Project 1: Binaural HearingSridhar Kalluri, SHRC
Research Question:What is the impact of hearing aids on binaural perception?
What we know:
Easier to understand target speech if other talkers are at different
locations
Target speech
Masker/interferer
Difficult to understand speech
Difficult to understand speech
Target speech
Masker/interferer
Easier to understand speechEasier to understand speech
Spatial separation benefitsnormal hearing listeners
Spatial separation benefitsnormal hearing listeners
0 4 8 12 16-9
-6
-3
0
3
Interferers ILD (dB)
Th
resh
old
SN
R a
t b
ette
r ea
r
Spatial Separation
Low
LowerIs
Better
High
Unaided
Spe
ech
Thr
esho
ld
Hearing aids can reducebenefit of spatial separation
Hearing aids can reducebenefit of spatial separation
0 4 8 12 16-9
-6
-3
0
3
Interferers ILD (dB)
Th
resh
old
SN
R a
t b
ette
r ea
rCompression
Spatial Separation
Low High
LowerIs
Better
Aided
Unaided
Spe
ech
Thr
esho
ld
Hearing loss reducesbenefit from spatial
separation
Hearing loss reducesbenefit from spatial
separation
0 8 16-9
-6
-3
0
3
Interferers ILD (dB)
Th
resh
old
SN
R a
t b
ette
r ea
r (d
B)
Normals
Impaireds
Normal hearing
Hearing loss
LowerIs
Better
Spatial Separation
Low High
Spe
ech
Thr
esho
ld
Hearing loss and hearing aid technology can affect binaural
benefit to speech understanding
Project 2: Listening Effort
Collaboration with
Dept. of Psychology, UC Berkeley
Prof. Ervin [email protected]
Anastasios Sarampalis
Project 2: Listening Effort
Research Question:
Do hearing aids reduce listening Effort?
What we know:
People have a limited capacity of attention/effort
If more attention is applied to one task, less can be applied to
another
Measure listening effort with aDual-Task Paradigm
Experiment A:
Effect of hearing aidson Driving
50
55
60
65
70
75
Driving Only w/ Speech
Dri
vin
g A
cc
ura
cy
(%
)
Listening to speech in noise makes driving worse
Listening to speech in noise makes driving worse
Adding directional technology makes driving better
Adding directional technology makes driving better
50
55
60
65
70
75
Driving Only w/ Speech w/ Speech &Directionality
Dri
vin
g A
cc
ura
cy
(%
)
Experiment B:
Effect of hearing aidson memory
Directional technologyimproves memory
Directional technologyimproves memory
0
0.5
1
1.5
2
2.5
Low High
Noise Level
# W
ord
s R
ec
all
ed
Noise reduction technologyimproves memory
Noise reduction technologyimproves memory
0
0.5
1
1.5
2
2.5
Low High
Noise Level
# W
ord
s R
ec
alle
dUnprocessedNoise Reduction
Experiment C:
Effect of hearing aidson reaction time
Reaction Time Task
Reaction Time Task
8
Reaction Time Task
7
0.5
0.55
0.6
0.65
0.7
0.75
0.8
Low HighNoise Level
Re
ac
tio
n T
ime
(s
ec
)
Directional technologyimproves reaction timeDirectional technologyimproves reaction time
Noise reduction technologyimproves reaction time
Noise reduction technologyimproves reaction time
0.5
0.55
0.6
0.65
0.7
0.75
0.8
Low HighNoise Level
Re
ac
tio
n T
ime
(s
ec
)
UnprocessedNoise Reduction
Hearing aid technology can reduce effort necessary to understand speech in noise
Conclusion
•Perceptual Science will play a strong role in technology development
•Cognition will be a focus of hearing impairment research and hearing aid
R&D
