4,546,779
`(11) Patent Number:
`United States Patent 9)
`
` Meno [45] Date of Patent: Oct. 15, 1985
`
`
`[54] METHOD OF MEASUREMENT OF
`EUSTACHIAN TUBE OPENING AND
`ASSOCIATED APPARATUS
`Inventor:
`[75]
`Frank Meno, Pittsburgh, Pa.
`[73] Assignee: University of Pittsburgh, Pittsburgh,
`Pa.
`
`4
`
`[21] Appl. No.: 560,143
`[22] Filed:
`Dec.12, 1983
`
`[51]
`tty C1?
`seeeeecrrsstenreserrnrseernnrnrsntes AGIB 5/12
`
`ceeeeeccsceesssssessseseeneseneecenenenensnseoens 128/746
`[52] US. Ch.
`[58] Field of Search
`128/746, 739, 773, 774
`— ;
`coe
`[56]
`References Cited
`U.S. PATENT DOCUMENTS
`.
`4,429,702
`2/1984 Von Recklinghausen......... 128/746
`FOREIGN PATENT DOCUMENTS
`2459648
`1/1981 France .
`0760955
`9/1980 ULS.S.R. cecesseeeneseeeneenes 128/746
`
`OTHER PUBLICATIONS
`Cabot, et al., “Detection of Phase Shifts in Harmoni-
`cally Related Tones”, Journ. of Audio Engr. Soc., vol.
`34, No. 7, 9-1976, pp. 568-571.
`Primary Examiner—Lee S. Cohen
`Assistant Examiner—Angela D. Sykes
`Attorney, Agent, or Firm—Arnold B. Silverman
`157]
`ABSTRACT
`A sound wavesignalis applied to the nasal cavity andis
`.
`.
`.
`picked up at the auditory canal of the ear ofa subject.
`The phase difference between the two signals is a mea-
`sure of the extent of opening of the Eustachian tube. By
`converting the two sound signals to electrical signals
`and transmitting them to a phase comparatorit is possi-
`ble to ascertain the changes in opening of the Eusta-
`chian tube during swallowing.
`
`11 Claims, 1 Drawing Figure
`
`Eustachian Tube
`Resistance
`
`10
`
`j
`Oscilicter
`
`12
`
`Audio
`Amplifier
`
`14
`
`Tubini 6
`ubing
`—
`To Nose
`
`28
`hone
`
`Mi
`
`.
`
`Middie Ear
`
`Model
`
`Amplifier
`
`
`30
`[ Compliance
`
`
`
`
`
`20
`
`22
`
`32
`
`se
`Phase
`
`Amplifier
`Comparator
`
`
`
`Display and Record
`Phase Difference
`
`Sony Exhibit 1010
`Sony Exhibit 1010
`Sony v. MZ Audio
`Sony v. MZ Audio
`
`

`

`U.S. Patent
`
`Oct. 15, 1985
`
`4,546,779
`
`82
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`

`1
`
`4,546,779
`
`METHOD OF MEASUREMENT OF EUSTACHIAN
`TUBE OPENING AND ASSOCIATED APPARATUS
`
`BACKGROUNDOF THE INVENTION
`1. Field of the Invention
`This invention relates to a method and apparatus to
`determine the extent and changes in the extent with
`time of Eustachian tube opening of a subject by measur-
`ing the phase difference and changes in the phase differ-
`ence with time of sound waves applied to the nose and
`detected in the ear canal of a subject.
`2. Description of the Prior Art
`French Pat. No. 2,459,648 teaches a method for mea-
`suring Eustachian tube opening wherein a signal of
`determined frequency is applied at the nostril of a sub-
`ject, is transmitted through the Eustachian tube during
`swallowing and, finally,
`is picked-up and measured in
`the ear. The patent states that the peak amplitudeof the
`signal picked up in the ear indicates the diameterof the
`opening of the Eustachian tube. However, the patent
`further states that the signal picked up by the auricular
`probeis likely to be fugitive and subject to interference.
`Therefore, the patented method prohibits measurement
`of the amplitudeif the signal picked up does not show a
`predetermined number of consecutive impulses, Le.
`does notlast for a predetermined time.
`As the method of the French patent publication mea-
`surementoffleeting or fugitive amplitudes,it is substan-
`tially incapable of measuring rapidly changing opening
`sizes such as occur when the Eustachian tube diameter
`is changing rapidly from its fully closed state upon the
`onset of swallowing or from its fully open state at the
`end of a swallow.
`There remains a need, for both clinical and research
`purposes, to obtain information concerning changes in
`the amount of Eustachian tube opening as a function of
`time, which involves determinations concerning the
`tube while its diameter is changing from its fully closed
`to open state and vice versa.
`SUMMARYOF THE INVENTION
`
`invention utilizes phase sonometry. It
`The present
`provides a method and apparatus to determine the
`amount of Eustachian tube opening and changes in the
`opening as a function of time by measuring the differ-
`ence of phase at a given time between the sound wave
`in the nose and in the auditory canal of the subject
`under test. The French patent does not relate in any
`way to measurement of sound wave phase differential
`between the nose and the auditory canal. By employing
`a phase differential method,
`the present
`invention
`avoids the many difficulties involving random reso-
`nances in the body that can cause the fugitive and inter-
`ference signals mentioned in the Frenchpatent. In addi-
`tion, the French patent teaches the useof a fixed, deter-
`mined frequency in order to measure the duration of
`any particular opening by counting consecutive im-
`pulses. In contrast to the method of the French patent,
`the present invention is not limited to any particular
`frequency, but a frequency sweep can be implemented
`to determine an optimum frequency for each patient
`tested. Finally, the opening of the Eustachian tube is
`changing most rapidly at the beginning and end of a
`swallow. These are the times the differential measured
`by the present methodis the largest and easiest to mea-
`sure but these measurements are most apt to be prohib-
`
`5
`
`10
`
`— 5
`
`35
`
`40
`
`45
`
`60
`
`2
`ited according to the French patent because they are
`the most transitory.
`invention measures the
`In summation,
`the present
`phase shift between electrical signals in the nose and in
`the ear representing the phase shift in sound signals at
`the same Jocations in order to alleviate the problems
`inherent in the amplitude measurement method of the
`Frenchpatent, due to various resonancesin the passage-
`ways of the nose and the ear.
`The Eustachian tube represents a variable resistance
`to air flow, depending upon the degree of opening dur-
`ing swallowing, from its normally closed condition. As
`the Eustachian tube extends from the nasal cavity to the
`middle ear, there is a pressure rise and fall in the middle
`ear depending upon the opening of the tube. As the
`middle ear represents a compliant chamber,its pressure
`will lag pressure changes in the nasal cavity. Conse-
`quently, by continuously measuring the phase delay,it
`will be possible to determine the amount of Eustachian
`tube opening as a function of time.
`The present invention applies a sound wavesignal
`obtained through an oscillator, audio amplifier and
`speaker to the nasal cavity where the applied signal
`induces sinusoidal air pressure waves. These pressure
`waves are detected by a pressure sensor or microphone
`in or adjacent the nasal opening, amplified and fed as a
`first electrical input signal to a phase comparator. A
`microphone is placed in or adjacent the ear to pick up
`the transmitted sound signal reaching the auditory canal
`and the signal detected in the ear is amplified, filtered
`and fed as a second electrical input impulse to a phase
`comparator. The output signal from the phase compara-
`tor, based on the input signal fed thereto, represents the
`phase shift or differential between the input and output
`sound signals andis both displayed and recorded versus
`time.
`It is an object of the invention to provide a method
`and apparatus for measuring the opening and changesin
`the opening of the Eustachian tube as a function oftime.
`It is another object of the present invention to pro-
`vide such a method and apparatus which may be em-
`ployed efficiently without requiring extensive training
`of personnel or expensive equipment.
`It is another object of the invention to provide such a
`method and associated apparatus which are adapted to
`provide rapid and accurate measurements.
`These and other objects of the invention will be fully
`" understoodfrom the following description of the inven-
`tion on reference to the illustrations appended hereto.
`
`BRIEF DESCRIPTION OF THE DRAWING
`
`The FIGUREpresents a schematic diagram of a
`combination of elements arranged to measure the phase
`shift of sound waves between the nose and the ear. The
`individual elements in the combination are not de-
`scribed in detail because each is readily known to those
`skilled in the art.
`
`DESCRIPTION OF THE PREFERRED
`EMBODIMENT
`
`’ Referring to the FIGURE, an electrical signal of
`desired frequency is induced in oscillator 10 and is
`passed through audio amplifier 12 and speaker 14. The
`resulting soundsignal leaving speaker 14 passes through
`tube 16 to the nose of an individual, such as a human
`patient, for example. The sound signal induces pressure
`waves in the nasal cavity of the patient which are de-
`tected by pressure sensor 18, amplified in amplifier 20
`
`

`

`3
`and transmitted as an input electrical signal to phase
`comparator 22.
`The sound input to the nasal cavity passes through
`the Eustachian tube, which is symbolically represented
`as an electrical resistor 24 because it is subject to vari-
`able closure and opening,
`thus presenting a variable
`resistance to the passage through the inner ear whichis
`a chamber and which is symbolically represented as a
`capacitor 26.
`Sound waves passing through the inner ear enter the
`auditory canal where they are picked up by microphone
`28 and convertedto an electrical signal which is ampli-
`fied in amplifier 30 and filtered to remove extraneous
`signals in filter 32. The output from filter 32 constitutes
`an electrical signal to phase comparator 22.
`Phase comparator 22 produces an output signal
`which represents the phase shift between the input
`sound signal to the nasal cavity and the output sound
`signal picked up in the auditory canal and which can be
`displayed, computed and/or recorded by means 34. The
`extent of the phase shift will depend upon the relative
`opening of the Eustachian tube and can be correlated
`therewith, the shift being greater upon closure of the
`Eustachian tube and lesser upon opening of the Eusta-
`chian tube.
`Whereas particular embodiments of the invention
`have been described above for purposesofillustration it
`would be evident to those skilled in the art that numer-
`ous variations of the details may be made without de-
`parting from the invention as defined in the appended
`claims.
`I claim:
`1. A method for determining the opening or changes
`in the opening with time of the Eustachian tube of a
`subject comprising applying an input sound wavesignal
`to the nasal cavity of the subject, converting the input
`sound wavesignal to a first electrical input signal, feed-
`ing said first electrical input signal to a phase compara-
`tor, picking up a related output sound wavesignal at the
`ear of the subject, converting said output sound wave
`signal to a second electrical input signal, feeding said
`second electrical input signal to said phase comparator,
`and said phase comparator indicating the phase differ-
`ential between said input sound wave signal and said
`output sound wavesignal, whereby said phase differen-
`tial may be employed to determine the opening or
`change in opening with time of said Eustachian tube.
`2. The method of claim 1 including establishing sinu-
`soidal pressure waves by means of said input sound
`
`4
`wave signal, and sensing said sinusoidal pressure waves
`and converting them to said first electrical input signal.
`3. The method of claim 2 wherein said input sound
`wavesignal is provided by an oscillator, audio amplifier
`and speaker combination.
`4. The method of claim 1 wherein said output sound
`wavesignal is received by a microphone, amplifier and
`filter combination.
`5. The methodof claim 1 wherein said phase compar-
`ator displays said phase differential and records said
`phase differential versus time.
`6. A sonometric apparatus for measuring Eustachian
`tube opening comprising oscillating sound producing
`means for providing a sound waveinput signal to the
`nasal cavity of a subject; sound wave pick-up meansfor
`detecting said sound wavesignal at the ear of the sub-
`ject;
`first amplifier means for amplifying said sound
`wave input signal as a first electrical signal; second
`amplifier means for amplifying said sound wavesignal
`picked-up at the ear as a second electrical signal; and
`phase comparator means for receiving and comparing
`said first electrical signal and said second electrical
`signal and emitting a signal corresponding to the phase °
`difference between said first and second electrical sig-
`nals, said phase difference being employed to to deter-
`mine the opening or change in opening with timeofsaid
`Eustachian tube.
`7. The apparatus of claim 6 wherein said oscillating
`sound producing means includes oscillator means for
`creating a sound wavesignal, audio amplifier means for
`amplifying said sound wavesignal, and speaker means
`for emitting said sound wavesignal, in combination.
`8. The apparatus of claim 6 wherein said sound wave
`pick-up means includes microphone means for picking
`up said sound wave.
`9. The apparatus of claim 6 wherein said first ampli-
`fier means includes pressure sensor-amplifier means in
`combination for sensing and amplifying sinusoidal pres-
`sure waves of the subject.
`10. The apparatus of claim 6 wherein said second
`amplifier means comprises amplifier-filter means in
`combination for amplifying and filtering said sound
`wave signal picked up as a second electrical signal.
`11. The apparatus of claim 6 including phase compar-
`ator display and recording means, and said phase com-
`parator display and recording means being operatively
`associated with said phase comparator meansto receive
`signals therefrom.
`*
`*
`*
`*
`*
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`4,546,779
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`
`UNITED STATES PATENT AND TRADEMARK OFFICE
`CERTIFICATE OF CORRECTION
`
`
`
`> 4,546,779
`PATENT NO.
`- Oct. 15, 1985
`DATED
`: Frank Meno
`INVENTOR(S)
`It is certified that error appears in the above-identified patent and that said Letters Patentis hereby
`corrected as shown below:
`;
`
`Column 1,
`
`line 19, "picked-up" should be --picked up--.
`
`Column 1, line 29, "publication" should be --prohibits--.
`
`Claim 6, column 4, line 20, "picked-up" should be
`--picked up--.
`- Claim 6, column 4, line 25, “employed to to" should be
`--employed to--.
`
`
`
`
`
`
`
`
`Signed and Sealed this —
`Twentieth Lay Of May.1986
`
`
`
`
`
`[SEAL]
`
`Attest:
`
`Attesting Officer
`
`' Commissioner ofPatents end Trademarks
`
`DONALD J. QUIGG
`
`
`
`