Download Tactile Auditory Sensory Substitution - Computer

Tactile Auditory Sensory
Substitution
Ryan Thome, Sarah Offutt, Laura
Bagley, Amy Weaver, Jack Page
BME 200/300
December 8, 2006
Client:
Veronica H. Heide, Au.D.
Audible Difference
Advisor:
Mitchell E. Tyler, P.E., M.S.
Dept. of Biomedical Engineering &
Dept. of Ortho-Rehab Medicine
University of Wisconsin - Madison
Abstract
High frequency hearing loss is a problem common among
people of all age groups. People suffering from this type of
hearing loss often lose the ability to hear certain consonant
sounds, and as a result have difficulty communicating with
others. The goal of the project is to use sensory
substitution, a technique for presenting environmental
information missing in one sensory modality to another, to
help replace this missing high frequency information. The
device takes recorded information, filters it into four
different channels based on frequency, then outputs all four
channels to a sound card. The sound card outputs to a
circuit that amplifies the sound and reduces the noise. The
circuit then outputs to four transducers. Use of this device,
in conjunction with the lower frequency audio information
gathered directly by the user, should allow the user to
better communicate by speech and hearing.
Problem Statement
The goal is to design and develop an
auditory substitution device that through
the use of vibro-tactile stimulation can
substitute for regional frequency hearing
loss, in order to aid in daily
communication needs.
Sensory Substitution

Presenting environmental information absent in
one sensory modality to another

Examples:



Long Cane - visual navigation substitution through touch
Sign Language - speech substitution through vision
Braille - visual text substitution through touch
Existing Devices

Tickle Talker



Tactaid 7


Electric shock on sides
of fingers
One electrode per range
of frequency
Vibro-tactile stimulation
on sternum, abdomen,
forearm or neck
Tacticon 1600
http://us.st11.yimg.com/us.st.yimg.com/I/audiologic
alengineering_1903_431188
High Frequency Hearing Loss





Sensorineural
Normal hearing =
50 – 20,000 Hz
Above 1,000 Hz is
lost
Loss of ability to
hear certain high
frequency
consonants
Like hitting piano
key with no
strings
Krames Communications.
System Diagram
Person
Speaking
Audio Waves
Microphone
Analog
Voltage
Signal
Multi-channel
Amplifier
Digital Signal
Analog Voltage
Signal
Sound Card
Amplified
Analog
Voltage
Signal
Transducers Vibrational Pulses
User
Cool Edit
Digital Signal
that has been
filtered to
specified
frequency,
amplitude,
and channel
divisions
“Cool Edit” Software


Audio input is filtered for specific frequency range
Becomes separate channels




1:
2:
3:
4:
1.6-2.0
2.0-3.0
3.0-3.5
4.5-8.0
kHz
kHz
kHz
kHz
–
–
–
–
p, i, m
ch, sh
f
s, th
Sound Card
Turtle Beach Audio
Advantage Roadie
 Able to output up
to six channels
 Voltage output 0-60
mV

Circuit

Parts






Amplifies signal
Reduces noise
Initial voltage output



Four comparators
Four transducers
10kΩ and 1kΩ Resistors
0-50mV
Amplified 11x
Current draw

0-2mA
Output
Piezoelectric
buzzers
 Placed on neck
with Bioflex®
adhesive
 Transducers buzz if
amplitude in that
channel exceeds a
voltage of 1 V

Word Discrimination

Joe took father’s shoe bench out he was
sitting on my lawn.

Pairs of words that can be distinguished
with device




Sixty versus Fifty
Shirt versus Church
Much versus Such
Sob versus Shop
Word Pairs
Sixty - Fifty
Much - Such
Future Work
Acquire and implement vibro-stimulators
 Minimize size
 Real time
 Specific sound analysis

References

Audiological Engineering Corp. (n.d.) Tactaid 7. Retrieved 29 September, 2006 from
http://www.tactaid.com/tactaid71.html.

Better Hearing Institute (BHI). Hearing Loss- The Prevalence of Hearing Loss. 20052006. Date Vistied: 10/13/2006. http://www.betterhearing.org/hearing_loss/prevalence.cfm

Fairbanks, G. Voice and Articulation Drill Book. Harper & Row Publishers; New York, 1960. Pages
88-104.

Kaczmarek, K. A., Webster, J. G., Bach-y-Rita, P. and Tompkins, W. J. Electrotactile and vibrotactile
displays for sensory substitution systems 1991.

Krames Communications. (1995). Hearing Aids. [Brochure]. San Bruno, CA.

“Piezoelectric Transducers.” NDT Resource Center. 19 October 2006
http://ed.org/EducationResources/CommunityCollege/Ultrasonics/EquipmentTrans/piezotransducers
.htm.

Scapa. (2006). Bioflex. Retrieved 31 November, 2006, from
http://www.scapana.com/productdetail.jsp?productid=3637&search=products

Webster, John G. (2003). Bioinstrumentation. Indianapolis, IN: John Wiley & Sons Inc.