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Harvey DillonDirector, National Acoustic Laboratories
Parliamentary BreakfastHearing Awareness Week, 2012
Hearing aids – how much do they really help?
Economic impact
Untreated hearing loss leads to $11.75 bn p.a. in lost economic activity – Access Economics – Listen Hear! (2006)
$6.7 bn from productivity loss (lower work-force participation and effectiveness)
Aust
ralia
ns w
ith h
earin
g lo
ss p
er
year
of a
ge 3.1m – 14%
3.8m – 15%
4.8m – 17%
20 30 40 50 60 70 80 90 100 -
20,000
40,000
60,000
80,000
100,000
120,000
140,000
160,000
Age
2030
2020
2011
≥101
Use of hearing aids by new clients in Hearing Services Program
None < 1 hr/day 1-4 hrs/day 4-8 hrs/day >8 hrs0
5
10
15
20
25
30
35
40
20042010
Perc
enta
ge o
f clie
nts
Dillon, Hickson & Lloyd (2012)
Impact of needCu rre n t e ffe ct: F(4 , 4 9 0 )=8 5 .5 0 2 , p =0 .0 0 0 0
V e rti ca l b a rs d e n o te 0 .9 5 co n fi d e n ce i n te rva l s
1 2 3 4 5
N eed
1.5
2.0
2.5
3.0
3.5
4.0
4.5
5.0
5.5
6.0
IOI-H
A score
B ene fi t Res idua l d i ffi c u l ty
Aid ownership by hearing lossBlue Mountains Population >55 years
0
20
40
60
80
100
5 15 25 35 45 55 65 75 85 95 105 115
4FA Hearing threshold (dB HL)
Pe
rce
nta
ge
of
pe
op
le
0
20
40
60
80
100
5 15 25 35 45 55 65 75 85 95 105 115
4FA Hearing threshold (dB HL)
Per
cen
tag
e o
f p
eop
lePopulation
Ownership
Ownership
Use
Hartley et al (2012)
Speech intelligibility (mild loss – 22 dB 3FAHL)
0
20
40
60
80
100
30 40 50 60 70 80 90
Background noise level (dBA)
Sp
eech
in
tell
(CS
T %
)
Norm hear
Direct
Omni
Unaided
• Hearing aid “helps” in quiet places
• Tiny additional benefit from directivity
Conditions:
DI = 3 dB when REIG > 3 dB
n.h. spatial adv = 6 dB
∆SNR re n.h. = -3.7 dB
Speech intelligibility (moderate-severe loss – 54 dB 3FA HL)
0
20
40
60
80
100
30 40 50 60 70 80 90
Background noise level (dBA)
Sp
eech
int
ell (
CS
T %
)
Norm hear
Direct
Omni
Unaided
Conditions:
DI = 3 dB when REIG > 3 dB
n.h. spatial adv = 6 dB
∆SNR re n.h. = -7.7 dB
Effects of hearing loss
Leisure noise
Hearing damage
Difficulty hearing in
noise & reverb
Workplace noise
Environmental factors
Genetic pre-dispositions
Depression, decreased
independence,quality of life,
…….
Age $6.7 bn loss
Cessation of work;
Under-achievement
at work
Social withdrawal
Technology of the next few years
Super-directional hearing aids
Binaural-Processing Super-directional Microphone (Mejia & Dillon, 2007)
W3 W4
∑
∑
Rout
K
Rear- directional array
Masking threshold
Cross-fading process
Outputs with spatial reconstruction
HRTFL HRTFR
Z-d
d = 3 ms delay
(Precedence effect)
DOA- reconstruction
Q1 Q2 Q3 Q4
∑
Binaural beamformer
Main directional signal
W1 W2
∑
∑
Lout
K
Subsidiary signal
Video demo
Super-directional microphones (mild loss)
Conditions:
DI = 6 dB when REIG ≥ 0 dB
n.h. spatial adv = 6 dB
∆SNR re n.h. = -3.7 dB
40 45 50 55 60 65 70 75 80 85 900.0
10.0
20.0
30.0
40.0
50.0
60.0
70.0
80.0
90.0
100.0
n.h. Dir
Omni Unaided
Background noise level (dBA)
CS
T s
pe
ec
h in
telli
gib
ility
(%
)
Hearing aids of the future
?Convergence: • phone interface,
• computer interface,
• music player,
• GPS interface
• hearing protector,
• hearing aid/enhancer,
Thanks for your interest
In summary
• With changes in technology, usage of hearing aids within the Government's Hearing Services Program has significantly increased over the past five years.
• Hearing loss none-the-less remains more often uncorrected than corrected, particularly among people with mild and moderate hearing loss.
• Imminent further improvements in technology will likely result in hearing aids enabling some people with hearing loss to hear more clearly than people with normal hearing. This will likely smash negative perceptions and stigma that still sometimes are associated with the use of hearing aids.
• A demonstration of future super-directional hearing aid technology will be provided.
