A physiological signal transmission
model for specific diagnosis of
cochlear hearing loss
Amin Saremi
Supervisors:
Stefan Stenfelt
Elina Mäki-Torkko
Why do we do this project?
. Most of complicated functions of
human auditory system are
attributed to inner ear
. Suboptimal diagnosis techniques
despite the large number of
’sensorineural ’patients
Why modeling?
Cochlea
Organ of Corti
It ALL happens in organ of
Corti!
. Alfonse Corti (1851)
. Helmholtz (1863)
. Rayeleigh (1877)
. Georg Von Bekesy (1960)
. Neely and Kim (1983)
Photo by: Professor Helge Rask Andersen, Uppsala Universitet
Cochlear mechanics
• Micro-mechanics
• Macro mechanics
Micromechanics vs. Macromechanics
.position-frequency map of basilar membrane
. Helmholtz’s mistake (fork tunes)
Our suggested model for passive vibration
• Mechanical analogy:
• Equivalent electrical analogy:
Active processes
. Von Bekesy’s travelling wave can not explain the ’compression’,etc
. Active processes: It ALL happens in OHCs!
. Somotic motor and hair bundle motor
Our model for Active OHC
MET (mechano-electrical trasnduction)
Voltage-controlled somotic motor
Putting things together
• Integrating the passive vibrations and OHC
active performances together
• MATLAB simulation
What is special about this model
• Loyalty to physiology
• Ability to pin point the cochlear lesion
• Paving the way towards modeling more
central parts of auditory system (neural and
cognitive aspects)
HOT topics!
• Two major types of sensorineural hearing
impairments are studied
• Noise induced impairment: damaged outer
hair cells
HOT topics!
• Presbyacusis: are the
cochlear potentials playing a
role?
• Changes in this 80mV resting
potential moves the
operating point of the MET
curve....hmm...How does the
model predict its effects?
Future work
• Today’s high-tech hearing
aids: much better selectivity
and higher quality of
percieved sound
• Knowing the specific source
of cochlear lesion, using the
model, more clues might be
obtained for newer signal
processing solutions
Future hearing aids!
different solutions for different people!
Future hearing aids!
Some people need even more advanced
solutions!