A different look at HEARING

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A different look at HEARING
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Do we hear perhaps different from what hearing
experts assume?

• Willem Chr. Heerens

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According to physicsour hearing sense can
functioncompletely different.
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YES WE DO !
I say frankly
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May I introduce myself
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• Willem Chr. Heerens 1940
• Masters degree in physics
  1967
• Doctors degree in technical sciences
  1979
• Earlier retirement as associate professor
  TU-Delft 1999
• Papers about hearing www.slechthorend-plus.nl
  2003

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Relevant for my contributions in hearing issues
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Technical expertise particularly in

• Mechanics Membrane plate displacements.
• Vacuum technology pressure measurement.
• Physics transport phenomena hydrodynamics.
• Electricity magnetism.
• Sensor technology electrical measurement
  techniques.
• Fourier analysis special function theory.
• Differential integral mathematics.
• Complex function theory.

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Hearing expertise

• Since 1985 as Ménière patient Expert in
  the field.

• During quite a couple of years direct
  observations of several hearing phenomena and
  effects.
• Since 2001 Autodidact and theoretic hearing
  researcher.

• Meanwhile designer of a revolutionary and
  alternative
• COCHLEAR MODEL

Based on stringent application of laws and rules
of physics.

• What perhaps can lead to a
• paradigm shift

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Therefore the intriguing title
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According to physicsour hearing sense can
functioncompletely different.
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Points of criticism on the existing models
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• Mostly they offer only solutions for parts of the
  total subject.

• Too many phenomena remain unexplained.
• Mostly unexplained phenomena are ascribed to
  functioning of the brain without clear evidence.
• New refined investigations offer a growing number
  of anomalies that undermine the existing hearing
  sense models.
• Respectable research quite often fails plausible
  logic explanation.
• But above all
• Several hypotheses declared as basic theory are
  in conflict with fundamental physics laws and
  rules.

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Our hearing sense schematically
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• Concha
• Outer ear channel
• Eardrum
• Ossicular chain.

• Eardrum muscle
• Cochlea
• Hearing nerve

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The cochlea in detail
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stirrup
helicotrema
oval window
scala vestibuli
organ of Corti
scala media
round window
scala tympani
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Scala media in detail
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scala vestibuli
tectoriaal membrane
Reissner membrane
inner hair cell
outer hair cells
scala media
common connection to the brain
basilar membrane
hearing nerve
scala tympani
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Ernest Glen Wever and Merle Lawrence  The
acoustic pathways to the cochlea  JASA
1950 July, 22 460-467
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A remarkable experiment from 1950

• Experiment
• In a cats ear they eliminated eardrum
  ossicular chain.
• They fabricated a tube around the round window to
  isolate it acoustically from the oval window
  area.
• They stimulated with pure tones as follows
• Stimulus only on the oval window.
• Stimulus only on the round window.
• Stimulus on both windows with different phases,
  varying in phase between 0o and 180o
• They recorded the cochlear microphonics, the
  signal that is widely and directly brought into
  connection with the signal via the auditory nerve.

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Results
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• Independent stimulation of each window with the
  same signal resulted in equal changes in
  cochlear microphonics CM.

• Combined stimulation of both windows in the same
  direction 0o resulted in
• CM 0

• Stimulation of both windows in opposite
  directions 180o phase shift resulted in
• CM maximal

• That maximum was 6 dB higher than each of the
  two stimuli alone performed.
• In-between phase settings evoked vectorial
  increase of CM from 0 to a maximum at phase
  differences of the stimuli from 0o to 180o.

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Quite recently verified by
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S.E. Voss, J.J. Rosowski, W.T Peake Is the
pressure difference between the oval and round
windows the stimulus for cochlear responses?
JASA(1996) Sep.,100(3) 1602-16.

• which resulted in

• Affirmation of the results of Wever Lawrence.

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Conclusions
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• Wever Lawrence
• It is proven that the stimulation of the same
  sensory cells takes place via each of the two
  ways with the same intensity pattern.

• Over almost the total frequency range a minimum
  in response is obtained if both waves stimulate
  in phase the oval respectively the round window.

Voss, Rosowski, Peake

• The pressure differences between the oval and
  round window are in good approximation the
  effective acoustic stimulus for the cochlea.

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My conclusions
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• An electrical response CM or CP is only evoked
  in case of an evoked perilymph movement in the
  combined ducts of scala vestibuli SV and scala
  tympani ST.

• In case of maximal cooperation between the two in
  size equal stimuli 180o phase shift the total
  movement stimulus is two times larger.
• But then the changes in electrical response are
  not two but four times as large.
• Just because 10 10log 4 6 dB
• The electrical response in the inner ear is
  proportional to the
• square of the de perilymph velocity.

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differentiating and squaring
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Our hearing sense is

• But then the question rises

Does there exist in physics such a relationship?
And the answer is yes already known for a
long time
Bernoullis law
published in 1738.
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And that law of Bernoulli is formulated as
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• In a floating liquid the sum of the static and
  dynamic pressure is constant.

Static pressure pressure on the walls of
the duct. Dynamic pressure pressure that
the particles are evoking on each other
due to their floating. Dynamic
pressure is proportional to the square of the
liquid velocity v and the density r of the
liquid.
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Bernoullis law expressed in a formula
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• and applied on the cochlear duct
• Pressure evoked on the wall of scala tympani, so
  also on the basilar membrane
• Dp - ½ r v2
• Dp change in pressure Pa
• r density perilymph kg/m3
• v velocity perilymph m/s

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To what result leads this for a single tone with
frequency f ?
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• The sound wave evokes in front of the eardrum
  subsequent increases and decreases of pressure
• DP DP0 sin2pf t
• The deflection of the eardrum is proportional to
  that
• U U0 sin2pf t
• Via a reduction by the ossicular chain this
  also counts for the stirrup and the perilymph
  movement
• A A0 sin2pf t

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• Deflection or displacement of the perilymph
• A A0 sin2pf t

• Results into a velocity
• v A0 2pf cos2pf t

Velocity time derivative of deflection or
displacement.
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From perilymph velocity to membrane pressure
presented in a figure
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• That pressure stimulus on the basilar membrane
  given by
• Dp - ½ Dp0 - ½ Dp0 cos4pf t

exists of Not hearable static pressure
stimulus - ½ Dp0 Proportional to the average
sound intensity/energy. Hearable dynamic
pressure stimulus - ½ Dp0 cos4pf
t Proportional to the instantaneous sound
intensity/energy.
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And what happens in case of two tones with
frequencies f1 and f2 ?
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• Sound wave ? time dependent pressure increase and
  decrease according to
• DP DP1 sin2pf1t DP2 sin2pf2t
• And all the following mathematical steps are
  almost similar to those of one frequency, until
  the perilymph velocity
• But then the squaring of the perilymph velocity
  must be carried out according to the following
  algebraic rule
• (a b)2 a2 2ab b2

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The mixed term can be handled as follows
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• Using goniometric rules for multiplied sinus and
  cosine functions
• 2 cos a cos b cos (a - b) cos (a b)
• finally for the contributions to the stimuli on
  the basilar membrane can be written
• The difference frequency contribution
• - ½ Dp0m cos2p(f1 - f2) t
• The sum frequency contribution
• - ½ Dp0m cos2p (f1 f2) t

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The final result?
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• Each two evoked pure tones f1 and f2 together
  result in five distinguishable signals on the
  basilar membrane, given as
• A frequency independent contribution proportional
  to the average sound intensity.
• For each tone a one octave higher than the
  offered frequency signal
• 2f1 respectively 2f2
• A sum frequency f1 f2
• A difference frequency f1 - f2 pitch or
  basal tone.

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In the form of a figure
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But now you must realize the following
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• At least according to physics not in our brain
  but in our hearing sense the missing fundamental
  or pitch is generated.
• And for the total nerve signal counts
• 1 tone ? 1 frequency 1
  static signal
• 2 tones ? 4 frequencies 1
  static signal
• 100 tones ? 10.000 frequencies 1
  static signal
• Which is a real ENIGMATIC CODE.

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The consequences
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• Georg Von Békésys mystery of the missing
  pitch
• is no mystery anymore.
• Therefore violin virtuoso Tartini could let his
  soprano violin sound as a cello.
• On smaller church organs the 32 feet pipe is
  missing. But if the organist let sound in the
  proper amplitude ratio simultaneously the 16
  feet and 10 2/3 feet pipes, his audience will
  nevertheless hear that very low bass tone of that
  huge pipe.
• But their stomach does not vibrate as well. That
  only happens when that bass pipe really sounds.
• The theoretical textbooks about virtual pitch
  in sound perception can be added to the historic
  archive.

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But there is more
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• Is a very young child be gifted with musical
  talent?

• All those extra frequencies are unbearable to
  hear in a squaring hearing sense. Just
  construction not musicality.

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What about the Cochlear Amplifier
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• The stressing of the tensor tympani gives a
  change in signal transfer of about 30 times.
• The musculus stapedius also counts for a factor
  of approximately 30 times, maybe somewhat more.
• Together an effect of 1.000 times on the stimulus
  of the oval window.
• Due to the squaring this becomes 1.000.000 or
  60 dB.
• And the commanding signal for that?
• The static pressure signal on the basilar
  membrane can serve as such.

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Consequences of that hypothesis?
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• A static under pressure effect on the basilar
  membrane by any cause in the hearing sense
  result in hearing loss symptoms. Accompanied by
  pressure sensations in the ear.
• The unpleasant hearing sensations during takeoff
  or landing of an airplane.
• Increasing, sometimes temporarily, hearing
  impairment in case of increasing endolymfatic
  hydrops in Ménière patients.
• Sudden deafness, which sometimes can heal also
  spontaneously.
• Hearing impairment for airborne sound in case of
  the PET syndrome by pressure fluctuations in the
  middle ear cavity on the rhythm of the own
  breathing.

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And the other extremes?
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• Due to degeneration of large areas in the organ
  of Corti, also resulting in reduced transfer of
  the static pressure signal, a loss of dynamic
  range, known as
• Recruitment
• By a trauma or other phenomenon caused reduction
  or even total loss of functioning of the tensor
  tympani and/or musculus stapedius An
  extraordinary loud hearing of the somewhat louder
  sounds. A form of
• Hyperacusis
• But for this last phenomenon there are more
  causes to give.

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How does the phenomenon OAE fits in this model?
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• Thesis
• If a Spontaneous Oto Acoustic Emission SOAE is
  a reaction on earlier heard signals and is
  generated by tensor tympani / musculus stapedius,
  than that SOAE must have clearly traces of tone
  combinations evoked by the squaring process in
  the inner ear.
• That tone combinations must exist of
• Two frequencies with in the middle of them a
  third frequency. The so-called triplet
• A singular frequency equal to the frequency
  differences in the triplet. The pitch
  belonging to the triplet.

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Analysis of such an arbitrary SOAE spectrum
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• From the Nederlands Tijdschrift voor Natuurkunde
  September 2001
• Emile de Kleine Ear sounds on a wall-bed
  Title translated

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Determined spectrum
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VW very weak W weak M moderate S strong
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Results
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• 3 triplets with accompanying pitch.
• 6 triplets without a pitch.
• But pitch frequency was lower than the lower
  boundary of 800 Hz.
• Example triplet pitch
• Pitch Peak 6 f 1172 Hz
• Triplet Peaks 13 - 23 - 31 f 1674 - 2830
  - 3987 Hz.
• Triplet distances 1156 respectively
  1157 Hz.
• Accuracy generally within 1 of the pitch
  distance.
• This cannot be an accident anymore !

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The valid hypothesis for OAEs at this moment ?
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• That sounds completely different
• Those tones are evoked by a simultaneous effort
  of the outer hair cells, that evoke a backwards
  traveling wave in the cochlea into the direction
  of the oval window, and that finally via the
  ossicular chain brings the eardrum in motion.
• Which is in agreement with the common hypothesis
  of traveling waves in the cochlea.
• According to Georg von Békésys
• Traveling wave theory

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But in 2004 the following paper was presented
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• Tianying Ren Reverse propagation of sound in
  the gerbil cochlea
• Nature Neuroscience 7, pp 333 - 334 (2004) Brief
  Communications
• Subject of many discussions Pro and Contra.

• Experiment
• Laser interferometrical measurement of basilar
  membrane movements.
• Simultaneous registration of stirrup movements.
• With stimuli, normally evoking DPOAEs
  Distorsion Product OAEs.
• Measurement results
• There aren't found backwards traveling waves.
• Only a wavy movement, which equal to the normally
  incoming sound runs from the round window into
  the direction of the helicotrema.
• The stirrup moves a fraction earlier than the
  basilar membrane.

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Rens unintentional attacks on Von Békésys
Traveling Wave Theory
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• An earlier paper of Ren was also a hot item
• Longitudinal pattern of basilar membrane
  vibration in the sensitive cochlea
• Proceedings of the National Academy of Sciences
  - pnas.org PNAS December 24, 2002 vol. 99
  no. 26 17101-17106.
• Experiment
• Laser interferometrical measurements of the
  basilar membrane movement.
• In the 13,3 19 kHz area of the basilar membrane
  of a gerbil.
• Results
• The movement of the basilar membrane, from the
  higher frequency side towards the lower side, is
  restricted to 300 mm on both sides of the point
  of maximum activity.
• The shape of the movement was exactly symmetrical
  around this point.

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How do we have to interpret that wavy movement
of the basilar membrane ?
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• In this we have to observe the following facts
  in physics
• In a medium gas, liquid , solid material there
  exists a uniform relation between the propagation
  velocity v of sound or vibration, the frequency
  f and the wavelength l of the sound or
  vibration wave
• v f l
• v is lowest in gasses In air 330 m/s
  
• v in water but also in perilymph 1500 m/s
• v is highest in solid material to ca. 8000 m/s
• Together with the lowest 20 Hz and highest
  20.000 Hz sound frequencies that we are able to
  hear, the wavelength varies in the perilymph from
  75 meter to 7,5 cm.
• Always significantly larger than the size of the
  cochlea.

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Consequences
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• In the much shorter perilymph duct there cannot
  run a sound wave.
• The perilymph between oval and round windows is
  just able to move forwards and backwards as a
  whole.
• Tissue around the perilymph channel behaves more
  like a solid material than like a liquid.
• That tissue needs a larger size for a traveling
  wave.
• Conclusion
• There cannot propagate a traveling wave inside
  the cochlea.

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But what kind of movement is observed then ?
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• Therefore we must observe at first the way of
  movement of a singular resonator.
• A resonator exist of a body connected to a
  spring, and is possessing in practice also
  damping.
• If the body is given a deflection in opposite
  direction to the spring influence and that body
  is released, it will move harmonically with
  descending amplitude around the equilibrium
  point. The frequency in that case is known as
  resonance frequency fr
• If the resonator is brought into a vibrating
  movement, then three different situations can
  exist, dependent on the relationship between
  stimulus frequency f and resonance frequency
  fr
• with phase angle
• f lt fr reduced in phase movement
  0
• f fr increase due to resonance but also
  a phase retardation ½ p
• f gt fr strongly reduced movement in
  opposite direction p

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Followed by the remarkable mechanical setup of
the basilar membrane
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• This basilar membrane BM exists of an array of
  small resonators, that have gradually decreasing
  resonance frequencies from the round window up to
  the helicotrema.
• And then in case of an everywhere equal in phase
  stimulus on the entire BM, the following is
  happening
• All parts of the BM having fr gt f move in phase
  with the stimulus.
• That movement becomes larger if fr approaches f
  closer and will retard gradually in phase. In
  case of resonance a large movement is and there
  exist a phase retardation of ½ p.
• All parts of the BM with fr lt f are more and
  more moving in opposite phase with the stimulus
  and with a growing decreasing in deflection.

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And what phenomenon is comparable to this?
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• The wave in the stadium!

• And dependent on the quality factor in
  resonance, strongly coupled to the rate of
  damping, the moving area becomes smaller, while
  the maximum deflection becomes larger.
• On theoretical grounds it is no mystery that this
  wavy movement of the BM is always running from
  the round window base towards the helicotrema
  apex of the cochlea.
• It is a locally bound reaction behavior on a
  universally existing stimulus.
• Using the material specifications this behavior
  can be calculated in a perfect way.

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And if you calculate this and you make an
animation movie of it, it looks as follows
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• Round window
  Helicotrema ?
• Basilar
• membrane
• f / fr 0,1 Resonance
  point f fr
  f / fr 10
• High frequencies low frequencies ?

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But then the cochlear model still wasnt complete.
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• The fenomenon Bone conduction was still missing
  
• Based on my own experiences I observed that
• Bone conduction in principle does not differ that
  much from airborne hearing signals. So that
  stimulus should also undergo squaring.
• The bone conduction signal is in my case
  extremely strong if it is evoking vibrations on
  places on the skull where the skull bones are
  relatively thin.
• The construction of the cochlea inside the
  hardest bone in our body makes vibration transfer
  by means of deformation almost completely
  impossible.

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And after a further study of the anatomy I found
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• Next to the by me already known endolymphatic
  channel, between the cerebrospinal cavity and the
  cochlea there exists another direct connecting
  channel, the cochlear aqueduct.
• The cochlear aqueduct connection is relatively
  close situated in the vicinity of the round
  window in the scala tympani and exchanges
  perilymph between cerebrospinal cavity and the
  cochlea.

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And that brought me to the following hypothesis
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• Contrarily to what is generally assumed, bone
  conduction signals arent generated by vibrations
  of the petrosal bone, the bone structure that
  surrounds the cochlea.
• The bone conduction signal will be evoked by
  the push pull of perilymph via the cochlear
  aqueduct. And this happens on the rhythm of the
  vibration stimulus which is evoked elsewhere.
• In that case every area forming a part of the
  surroundings of the cerebrospinal volume with a
  greater elasticity and flexibility can be a
  candidate for the introduction of the bone
  conduction stimuli.

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Consequences of this hypothesis are
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• Similar as airborne sound stimuli, bone
  conduction stimuli evoke movements of perilymph
  in the perilymph duct.
• Due to the place where they are inserted in the
  cochlear duct, the movements evoked by bone
  conduction stimuli have opposite directions to
  those of the airborne stimuli.
• The push pull movement via the cochlear aqueduct
  is divided between flow directly towards the
  round window and flow along the basilar membrane
  via helicotrema towards the oval window.
• But due to the squaring effect according to
  Bernoullis law the bone conduction stimuli are
  transferred into the sound intensity signal, that
  will be sent to the brain.

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What does this mean for the ENT- practice ?
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• In case a child has an otitis media the middle
  ear cavity will be filled by fluid and due to its
  incompressibility this fluid will hinder the
  deflection possibilities of the round window. So
  the movement will follow the easiest way.
• Along the basilar membrane via helicotrema, oval
  window, the ossicular chain and the eardrum to
  the external environment. The bone conduction
  signal evokes a higher velocity of perilymph in
  front of the basilar membrane in the affected
  ear. So there is also evoked a stronger signal.
• The ENT-doctor puts a tune fork right in the
  middle of the childs forehead, and ask the
  child In which ear you hear the tone the best?
• The child will indicate its infected ear. The
  ENT-doctor will say Webers lateralisation is
  directed towards the affected ear.

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Or in case of a more complex case
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• If the Eustachian tube remains permanently open,
  like f.i. in case of the PET syndrome, the voice
  of the patient creates also a varying pressure in
  the middle ear.
• Under that pressure variations the eardrum will
  start to move and will not only transfer that
  motion to the ossicular chain, but will also put
  the perilymph in the cochlea into motion.
• But now with the same phase as the bone
  conduction sound signal, so this PET sound
  stimulus contribution and the also existing
  normal bone conduction signal are added up and
  create a higher total signal.
• Together with the impaired hearing mentioned
  before, the patient will hear his own voice
  louder and starts to speak at a lower level.

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An utmost tragic hearing history
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• End 1993 a woman got an enormous slam on her left
  ear. She developed not only in that ear, but in a
  somewhat moderate way also in her right ear an
  intense strong hyper sensitivity for all sounds
  above the minimum. Nobody believed her, so she
  was treated for almost 6 years as a psychiatric
  patient. Until she read in a tabloid that her
  hearing problems have a name Hyperacusis.
• Now again after visiting a number of hearing
  experts during years she is still confronted with
  much skepticism and there is no adequate aid for
  her. Actually experts still doesnt believe her,
  because they dont see reasons why a left side
  acoustic trauma can also create hyperacusis on
  the right side. And they observe her more as a
  neurotic person than as someone with a serious
  hearing problem.
• But with the perilymph push pull according to my
  cochlear model, hyperacusis is no longer
  something extravagant, but can be the result of
  overstretching the membranes on both sides. A
  completely normal phenomenon. Perilymph movements
  can be strongly enlarged, and after the squaring
  an utmost strong signal inside the cochlea can be
  evoked.

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Meanwhile on the website www.slechthorend-plu
s.nl
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• like the cases explained here, you can find a
  number of hearing phenomena that are explained in
  a logic and plausible way by using my proposed
  cochlear model.
• And this list is still growing.

54
Final conclusion
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• In case my cochlear model can be proven by
  reliable experiments as being correct, I am
  convinced that I have offered you here a view on

The holy grail of our auditory sense
If not, than I can start to enjoy my
pension. Thank you for your attention.