Acoustic Otoscope

Abstract

An acoustic otoscope may include a speculum tip for coupling to an ear canal; an excitation source for generating a dynamic volume or pressure coupled to the speculum tip, the excitation source dynamic volume or pressure being responsive to an input control; a pressure sensor for estimating the pressure in the speculum tip and returning a series of measurements; and a controller coupled to the excitation source input controls and also coupled to receive pressure sensor measurements.

Description

[0001] Cross-references

[0002] This application claims the benefit of U.S. non-provisional patent application serial number 15 / 995,793, filed on June 1, 2018, which is incorporated herein by reference. Technical Field

[0003] The present disclosure relates to an otoscope for characterizing fluid on the proximal surface of a tympanic membrane in a mammalian ear. Specifically, the present disclosure relates to measuring the viscosity of a fluid adjacent to a tympanic membrane by measuring the displacement of the tympanic membrane as a function of time and frequency in response to an acoustic volume excitation applied to the ear canal. Background of the Invention

[0005] Acute Otitis Media (AOM) is a common inner ear disease involving tissue inflammation and fluid pressure impinging on the tympanic membrane. AOM may be caused by a viral infection, which usually resolves without treatment, or it may be caused by a bacterial infection, which may develop and lead to hearing loss or other harmful and irreversible effects. Unfortunately, it is difficult to distinguish between viral or bacterial infections using currently available diagnostic devices, and the treatments for the two potential infections are very different. For bacterial infections, antibiotics are the treatment of choice, while for viral infections, the infection often resolves on its own, and antibiotics are not only ineffective, but may also lead to antibiotic resistance, which reduces their effectiveness in treating subsequent bacterial infections. Accurate diagnosis of AOM is important because AOM may be a precursor to chronic otitis media with effusion (COME), which is an indication for surgical drainage of the effusion and insertion of a catheter in the tympanic membrane.

[0006] The definitive diagnostic tool for inner ear infection is myringotomy, an invasive procedure that involves cutting into the eardrum, aspirating fluid, and examining the exudate under a microscope to identify the infectious agent in the exudate. Due to the complications caused by this procedure, it is only used in severe cases. This is a dilemma for medical practitioners because the prescription of antibiotics for viral infections is believed to lead to the evolution of antibiotic resistance in bacteria, which may lead to more serious consequences later in life, and there is no effective treatment outcome because the treatment of viral infectious agents with antibiotics is ineffective. Improved diagnostic tools are needed for diagnosing acute otitis media.

[0007] Purpose of the Invention

[0008] A first object of the invention is a device for estimating the mobility of the eardrum by introducing a volume displacement excitation into a sealed ear canal, the measurement of the eardrum displacement being performed using a measured pressure indicator in the eardrum.

[0009] A second object of the present invention is a method for determining the viscosity of a fluid adjacent to an eardrum by applying a volume displacement excitation, and developing measurements of the time and frequency domain characteristics of pressure as an indicator of eardrum displacement.

[0010] A third object of the present invention is an apparatus for characterizing fluid adjacent to the tympanic membrane, the apparatus having a speculum tip for sealing the ear canal, a volume displacement source for changing the volume of the ear canal, and a pressure measurement for determining the effect of the displacement change on the measured external auditory canal ear pressure, and thereafter generating an exudate metric based on the amplitude and phase of the pressure response to time or, equivalently, to frequency. Summary of the invention

[0011] In one example, the controller is operable to change the air volume of a chamber sealed to and coupled to the ear canal. The change in air volume coupled to the ear canal is referred to as AV(t) and is a function of time. A series of continuous or discrete pressure measurements are made over a time interval in which the air volume change occurs, and the air volume change is compared to the pressure measurement in at least one of a time domain response or a frequency domain response. In this way, the extent of displacement of the tympanic membrane in response to the change in air volume can be determined, and a viscosity measure can be formed. In an alternative embodiment, a pressure regulator can be used that introduces or removes a fixed volume of air to increase or decrease tympanic membrane pressure.

[0012] In another example, a method for determining the presence or extent of acute otitis media has a cyclic volume displacement step whereby a chamber having a dynamically adjustable internal volume is coupled to a sealed ear canal, for example via a speculum tip, the speculum tip including a pressure measurement sensor, the method comparing volume changes (as an excitation source coupled to the ear canal) with pressure changes measured in the ear canal (as a response), characterizing time domain static and dynamic responses to determine at least one of a frequency response or a time response of the tympanic membrane, the frequency or time response mapping a mobility metric from which the presence, absence, or composition of fluid adjacent to the tympanic membrane can be determined.

[0013] Aspects of the present disclosure provide an acoustic otoscope. The acoustic otoscope may include a speculum tip for coupling to an ear canal; an excitation source for generating a dynamic volume or pressure, the excitation source dynamic volume or pressure coupled to the speculum tip, the excitation source responsive to an input control; a pressure sensor for estimating the pressure in the speculum tip and returning a series of measurements; a controller coupled to the excitation source input control and also coupled to receive pressure sensor measurements; the controller thereby generating the excitation source input control and responsively acquiring a series of associated pressure measurements; the controller forming a series of differences by subtracting a scaled pressure measurement output from the excitation input; and deriving an exudate metric from the series of differences, the exudate metric having an increased exudate metric value in at least one of the following situations: the series of differences having an increased difference amplitude with a step change in pressure or volume compared to a subsequent difference; the series of differences having an increased difference amplitude for a low-frequency pressure or volume excitation compared to a difference amplitude for a high-frequency pressure or volume excitation.

[0014] In some embodiments, the scaled pressure measurement value can use a proportional factor that makes the midpoint value of the pressure measurement value substantially equal to the excitation source midpoint input value. In some embodiments, the excitation source input waveform can be sinusoidal. In some embodiments, the excitation source input waveform can be trapezoidal. In some embodiments, the series of differences can be averaged over at least 4 acquisition cycles. In some embodiments, the sinusoidal excitation source input waveform and the pressure sensor measurement waveform can be acquired at several frequencies to determine the corner frequency. In some embodiments, the corner frequency can be compared with the threshold frequency of a normal tympanic membrane, a viral fluid adjacent to the tympanic membrane, and a mucous fluid adjacent to the tympanic membrane to generate an exudate metric.

[0015] In some embodiments, the excitation source may include a movable diaphragm, a movable piston, or a differential pressure source coupled to the speculum tip via a hose. In some embodiments, the excitation source may include a diaphragm or piston enclosed in the speculum tip or speculum tip holder. In some embodiments, the excitation source may be coupled to a higher or lower air pressure source by controlling one or more valves by the excitation input.

[0016] Aspects of the present disclosure provide an acoustic otoscope. The acoustic otoscope may include a speculum tip having a seal for closing an ear canal, an excitation source that varies pressure or volume and is coupled to the speculum tip, the excitation source having an input, a pressure sensor coupled to the speculum tip and providing a pressure measurement output, a controller that generates an excitation source input waveform, the controller also coupled to the pressure sensor and receiving a pressure measurement output waveform, the controller generating the excitation input source waveform and simultaneously comparing the pressure measurement to the excitation waveform to form an exudate metric.

[0017] In some embodiments, the excitation source may cause at least one of a volume change or a pressure change. In some embodiments, the excitation source may be a moving diaphragm. In some embodiments, after establishing a monotonic sequence of a first threshold, a second threshold, and a third threshold, the exudate metric may be at least one of the following non-diagnostic speculum tip leak detections: a transfer function from a pressure measurement to an excitation waveform is below the first threshold; a high frequency transfer function from a pressure measurement to an excitation waveform is below the third threshold; a negative pressure response is detected when the excitation source is a volume adjustment piston or diaphragm returned to an original position; no pressure measurement change is detected in response to the excitation waveform.

[0018] In some embodiments, the volume excitation waveform can be a sinusoidal curve, and the exudate metric is based on a frequency response function where: ΔP(f) is the pressure amplitude at multiple discrete frequencies; ΔV(f) is the volume excitation amplitude at multiple discrete frequencies; and the corner frequency is when the response function is less than the value at a higher frequency. In some embodiments, the volume excitation waveform can be a trapezoidal waveform, and the exudate metric is based on the difference between the volume excitation waveform and the pressure measurement waveform, wherein the pressure measurement waveform is scaled to the midpoint of the waveform. In some embodiments, the midpoint can be the earliest time point among the time points at which the slope of the pressure measurement waveform changes to 1 / 4 or less of its initial value, or the midpoint can be a half-interval point, whichever occurs first). In some embodiments, the exudate metric can be based on the maximum amplitude of the difference waveform before the midpoint.

[0019] Aspects of the present disclosure provide a method for forming an exudate metric. The method may be operated on a speculum tip having an inspection port for coupling to an ear canal and tympanic membrane to be characterized. The speculum tip may be coupled to a pressure measurement sensor for measuring pressure in the speculum tip and a pressure excitation generator for regulating pressure in the speculum tip. The method may include forming a pressure excitation coupled to the speculum tip; measuring a pressure response; and determining, based on a transfer function of the pressure response to the pressure excitation, at least one of the following: a pressure seal leak; a healthy tympanic membrane; a tympanic membrane coupled to a watery fluid; a tympanic membrane coupled to a relatively viscous bacterial fluid.

[0020] In some embodiments, the determination can be based on comparing the first measurement of the healthy ear to the other ear. In some embodiments, the determination can be based on a characterization of at least one of: a frequency response corner frequency, a time delay of a step response, or a parameter fit of coefficients to an attenuation equation. In some embodiments, the attenuation equation is or Incorporation by reference

[0021] All publications, patents, and patent applications mentioned in this specification are herein incorporated by reference to the same extent as if each individual publication, patent, or patent application was specifically and individually indicated to be incorporated by reference. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The novel features of the present invention are particularly set forth in the appended claims. A better understanding of the features and advantages of the present invention will be obtained by referring to the following detailed description and the accompanying drawings which set forth illustrative embodiments in which the principles of the present invention are utilized, in which:

[0023] Figure 1 A schematic diagram of a pressure-responsive controller coupled to a human ear canal is shown.

[0024] Figure 2 Amplitude transfer plots and phase transfer plots for various exudate conditions are shown.

[0025] Figure 3A Plots of a first volume excitation and an exemplary response are shown.

[0026] Figure 3B Plots of a second volume excitation and exemplary responses are shown.

[0027] Figure 4 Plots of a third volume excitation and exemplary responses are shown.

[0028] Figure 5Plots of a fourth volume excitation and exemplary responses are shown.

[0029] Figure 6 A block diagram of an otoscope for measuring displacement of an eardrum in response to a displacement source is shown. DETAILED DESCRIPTION

[0030] Figure 1 An otoscope 130 is shown that includes a speculum tip 116 for insertion into the ear canal of a subject to be characterized. A lens 126 is coupled to an optical unit 114 that provides an examination of the external ear as provided by prior art otoscopes such as the WelchAllyn 25070-M. A pressure excitation generator 106 couples volume changes from the excitation generator to the speculum tip 116 through a hose 112, and a pressure measurement hose coupled to a pressure sensor 108 provides a measurement of pressure changes in the speculum tip 116 in response to the volume changes of the excitation generator. The speculum tip 116 is preferably sealed at the location where it is attached to the optical unit 114 so that the volume being excited is minimized to include only the volume of the ear canal and the speculum tip 116, or the speculum tip 116 may be sealed to the ear canal at other locations, including the concha and tragus at the entrance to the ear canal or at any location where a seal is achieved to the ear canal.

[0031] When inserted into the ear canal of the subject (see 122 for details), a comfortable seal 120 can be used that comfortably seals the speculum tip 116, thereby providing effective coupling of the volume change generated by the volume excitation generator 106 to the inner ear and the tympanic membrane 124. The volume (or pressure) excitation generator 106 can be any of the following: a voice coil incorporating a movable diaphragm, a diaphragm coupled to a piston actuator, or any mechanism that adjusts the volume or introduces an external pressure source, which is coupled to the speculum tip 116 to cause a pressure change (for example, by changing the closed volume or introducing and removing a gas, such as air, from a fixed volume), which couples the pressure change to the speculum tip 116 and the tympanic membrane. In this specification, although a volume adjustment device such as a diaphragm or a piston is described, it should be understood that the pressure change generated by the pressure excitation generator 105 can be formed by any volume displacement method. The volume change is intended to cause a very small change in the position of the tympanic membrane 124. If no fluid is present behind the tympanic membrane 124, the tympanic membrane is able to move freely and accommodate slowly varying (low frequency) volume changes with negligible pressure changes. If fluid is present behind the tympanic membrane 124, the tympanic membrane will exhibit reduced displacement for high frequency pressure changes. Additionally, for tympanic membranes coupled to watery viral fluids or mucous infectious fluids, the tympanic membrane may respond poorly to high frequency volume changes, which results in larger pressure changes for a given incremental volume change when there is fluid adjacent to the less mobile tympanic membrane, and the greater the mass of fluid present, the greater the movement contraction of the tympanic membrane at lower frequencies, resulting in greater induced pressures at higher frequencies.

[0032] When fluid is adjacent to the eardrum, the mobility of the eardrum is reduced, which results in greater pressure for a given volume change at high frequencies. Figure 2 , which shows the variation of the difference in pressure change (AP) divided by the difference in volume change (AV) as a function of frequency, scaled to units of AP / AV for a fixed TM. Curve 208 shows the pressure change versus volume change response curve for a healthy ear, which produces minimal pressure changes for incremental volume changes at low frequencies, and since there is no active tympanic membrane coupled to the adjacent fluid to track the displacement changes of the excitation generator, the volume of the system remains relatively fixed and pressure changes are minimal. The fluid adjacent to the TM adds mass and restricts the movement of the TM at higher frequencies, resulting in increased speculum 116 pressure at the lower frequency 212 of curve 206, and the "glue ear" with a fixed TM produces a response curve 204 with an associated corner frequency 210, where volume changes result in larger incremental pressures.

[0033] Figure 2The plots of show the transfer function of pressure / volume versus frequency, such as the sinusoidal volume modulation measured as a transfer function of pressure versus frequency. Each curve has a corner frequency where the transfer function flattens out with increasing frequency. Low frequency volume changes that do not produce pressure changes in the ear indicate that the tympanic membrane is moving freely at that frequency, and because the increased inertia of the adjacent fluid coupling prevents the tympanic membrane from moving freely, the pressure increases, and the various states of the tympanic membrane such as Figure 2 For example, a healthy tympanic membrane that is free to move without resistance over a wide frequency range is shown as waveform 208, with a corner frequency 214. In the presence of aqueous fluid from a viral infection behind the tympanic membrane, the mobility of the tympanic membrane 124 is reduced and is no longer able to respond to the intermediate frequencies (212) and produce speculum pressure modulations at these frequencies, as shown in the pressure / volume response curve 206. The final stages of the ear infection, in which bacterial material with a density greater than the viral aqueous fluid accumulates on the tympanic membrane and becomes "glue ear", further reduces the amplitude response and frequency range, as shown in curve 204, indicating that the tympanic membrane does not move in response to volume / pressure excitation, except at the lowest pressure excitation frequency 210. Each corner frequency 210, 212 and 214 is determined by the mass and volume of fluid restricting TM motion.

[0034] Figure 3A Another perspective and method for characterizing the TM using a frequency domain excitation curve 302 (sinusoidal volume changes) and corresponding pressure (used as an indicator of tympanic membrane position) 306 is shown. By examining the amplitude and phase delay 310 of the measured pressure curve 306 at a particular period 304, and repeating the measurement at other frequencies, a plot of phase delay 310 and amplitude can be derived from the response waveform 306. In another exemplary embodiment, the phase and amplitude response can be collected by using a chirp frequency excitation, where the chirp frequency varies in a period of continuously repeating cycles, thereby measuring the displacement response (via pressure) of the tympanic membrane to the volume excitation (chirp frequency displacement) in a single frequency sweep. The transfer function of the tympanic membrane can be determined as the familiar curve that normalizes the amplitude of 306 to the amplitude of waveform 302, where the phase delay 310 is expressed in degrees, both of which are measured as a function of frequency. The transfer function amplitude and phase can be used clinically, where thresholds are established for frequencies where the amplitude transfer function drops by 3dB or 6dB or the phase lags by 45 degrees to determine frequency breakpoints, where the frequency breakpoints can be used as a mobility metric, where a high frequency breakpoint indicates a normal ear, a low frequency breakpoint indicates exudate, and an even lower frequency breakpoint indicates jelly ear.

[0035] Figure 3BAn alternative time-domain response is shown, where a step change 320 in the applied volume is instantaneously made, and the pressure response curve 326 is observed, which similarly has a time-domain delay 324, as well as some rounded response associated with the loss of high-frequency components due to the mechanical inertia of the eardrum and the adjacent fluid, where the time delay 324 and the degree of rounding are related to the mobility of the eardrum, which can also be an indicator of whether there is an exudate, a serous exudate, or a dense bacterial mucoid exudate. Using Figure 3B the measured metric of the response 326 can use a time-response threshold to determine the health of the eardrum, where a relatively long time response 324 indicates glue ear, a shorter response indicates an exudate, and an even shorter response indicates a normal ear.

[0036] In another measurement method, a trapezoidal pressure excitation 402 is applied by the controller 104, and the pressure 406 measured at the speculum tip 406 is examined to determine a settling time t1 404, where the settling time t1 404 is the time when the instantaneous rate of change of the pressure decreases to, for example, 1 / 4 of its initial rate of change value, or the settling time t1 404 is selected as a specific fixed time 404, whichever occurs first. A scaling factor k is applied to the measured pressure waveform 406 such that at time t1 404, k*ΔP(t1) = ΔV(t1). When k is determined from this measured value, a difference waveform dP(t) 408 is calculated such that dP(t) = ΔV(t) - k*ΔP(t). The waveform 408 is examined, and the peak dP(max) is determined and tested according to the following criteria (where a first threshold, a second threshold, and a third threshold are established as a monotonically increasing sequence of thresholds):

[0037] If dP < T1 (the first threshold), then there may be no fluid;

[0038] If T1 <= dP <= T2 (the second threshold), then there may be serous fluid;

[0039] If T2 <= dP <= T3 (the third threshold), then there may be mucoid fluid or glue ear.

[0040] In another example, the difference dP(t) is formed by averaging AΔ(t) and ΔP(t) in a number of cases.

[0041] In another example, the volume excitation AΔ(t) rise time Tr 401 is varied over several consecutive cycles in a group, each group of pressure excitations is identical, the pressure response for each cycle is averaged to provide a composite ΔP(t), thereby providing a reliable pressure response for each group of cycles, and the rise time Tr 401 is varied in different groups of measurement cycles to characterize the tympanic membrane for various pressure excitation rise times.

[0042] In another example, the ΔV rise time 401 is reduced to a minimum, and the pressure response rise time 405 from 0 to tr and the fall time 406 from tr to t2 are examined and fitted to a curve. For example, the pressure rise time response 405 (or the t difference rise time 409) can be fitted as And the falling t time 408 is fitted as

[0043] in:

[0044] Pr(t) is the rise time of 405 or 409 from 0 to tr;

[0045] Pf(t) is the fall time of 406 or 408 deviating toward 0 at t2;

[0046] t is time (x-axis of the curve);

[0047] kl is the amplitude scaling constant;

[0048] T1 is the rise time coefficient determined by curve fitting and has time units;

[0049] T2 is the fall time coefficient determined by curve fitting and has time units;

[0050] After determining k1 and T1 or k2 and T2 based on at least one of the response waveforms 408, 409, 405 or 406, an exudate metric can then be formed, wherein a relatively long T1 or T2 and relatively large k1 and k2 indicate a lower likelihood of exudate or jelly ear, and a relatively short T1 or T2 indicates a higher likelihood of exudate, while a shorter T1 or T2 indicates a jelly ear when the values ​​of k1 and k2 are large, and wherein relatively small k1 and k2 values ​​(especially when accompanied by relatively short T1 or T2) can be used to indicate a poor seal (or perforated TM).

[0051] In another example, a burst of 5 or more cycles of sinusoidal volume excitation is provided as ΔV(t), and each cycle of the burst is used to average ΔP(t) the measured pressure waveform of a single cycle at frequency f to provide a pressure response point at a specific frequency f1, after which the frequency transfer function is calculated for each frequency f Afterwards, we can similarly Figure 2 The resulting transfer function response corner frequencies 214, 212, 210 are used as threshold frequencies to determine normal eardrum response, watery fluid behind the eardrum, and mucous or glue eardrum response, respectively.

[0052] In cases where an infection in only one ear is clinically suspected, the results of the left and right ears can be compared. Figure 2 , Figure 3A , Figure 3B , Figure 4 and Figure 5 Each of the above methods described in is used in a differential approach. The differential comparison approach of healthy-appearing ears to ears suspected of infection can provide standardization of diagnostic thresholds compared to models developed from the general population. For example, between a presumed healthy ear and a suspected infected ear, Figure 2 or Figure 3A The frequency breakpoints differ by a factor of 2 or Figure 3B or Figure 4 A factor of 2 in the time response difference can be used to determine exudate, and a factor of 4 or greater can be used to determine jelly ear.

[0053] In another example, the characteristics of the pressure response are examined for evidence of a leak in the seal 120. In the presence of a pressure leak in the ear canal, high frequency transmission is adversely affected, and if the seal is leaky enough, no pressure response to the pressure stimulus will be measured. Figure 4 The pressure curves 420 and 422 of FIG. 4 show an example of a speculum tip leak, where the change in piston / diaphragm volume 402 produces a transient positive pressure 420 and a subsequent transient negative pressure 422 when the piston / diaphragm moves in opposite directions. The duration of the measured pressure waveforms 420 and 422 can be examined to determine any of a number of conditions that can identify a bad speculum tip seal 120, which are not limited to:

[0054] 1) A shortened pressure-time response, which is less than the duration of the volume change stimulus;

[0055] 2) No pressure response during volume change excitation;

[0056] 3) Negative pressure response 422 in response to the volume regulating piston / diaphragm returning to its original position.

[0057] Figure 6An alternative tympanic membrane displacement measurement system is shown, which includes a piston (or diaphragm) 606 that is sealed 604 to form a closed chamber 608, where the displacement volume is coupled to a speculum tip 116 with an optical viewer 126 through a hose 112. A piston actuator 602 (which can be a voice coil actuator or other electromagnetic actuator) moves the piston 606 along the axis of the chamber 608, where the displacement measured by a sensor 614 is coupled to a displacement measurement 618. A central controller 601 issues commands to the piston actuator 602 to cause the piston 606 to adjust position, where the displacement 618 is measured and reported to the controller 601. The controller 601 also reads a pressure measurement 616 of the pressure generated in the speculum tip 116 that is transmitted from the chamber 608 to the speculum tip 116 through the hose 112.

[0058] In an exemplary embodiment, the piston diameter 606 is selected to have the same approximate diameter as a pediatric (or adult) tympanic membrane. The displacement of the piston 606 is adjusted and the pressure 110 is measured. For small pressure changes and a sealed system, the output value of the displacement measurement 618 can be considered an indicator of tympanic membrane movement. Therefore, for movement of the piston 608 that produces a small change in the measured pressure 616, the displacement of the piston 606 can be considered an indicator of tympanic membrane movement. In one example, the displacement of the piston 606 is swept and the breakpoints in the measured pressure measurement 616 frequency response are recorded, which frequency breakpoints represent the excitation frequencies at which the mobility of the tympanic membrane 124 is adversely affected by the adjacent fluid mass, which prevents high-frequency modulation of the tympanic membrane 124. View 650 shows an alternative diaphragm pressure actuator 603, wherein when a current is generated which causes a permanent magnet 656 to attract or repel, a voice coil 660 with a wire 658 is actuated, thereby displacing the diaphragm 652 relative to a flexible support 654 which provides a high frequency response for the diaphragm 652 in the enclosed space 608, coupled to the speculum tip 610 as before, or the excitation generator may be enclosed in Figure 1 in the speculum tip 116 or is enclosed in an adjacent housing 114.

[0059] Illustrative examples are provided for understanding the present invention, the scope of which is set forth in the following claims.

[0060] Although preferred embodiments of the present invention have been shown and described herein, it will be apparent to those skilled in the art that these embodiments are provided by way of example only. Without departing from the present invention, those skilled in the art will now expect many variations, changes and replacements. It should be understood that the various alternatives of the embodiments of the present invention described herein may be used to implement the present invention. It is intended to limit the scope of the present invention by the following claims, and thus encompass methods and structures and their equivalents within the scope of these claims.

Claims

1. An acoustic otoscope, comprising: (i) a speculum tip for coupling to the ear canal; (ii) a pressure sensor coupled to the speculum tip for estimating pressure in the speculum tip and providing one or more pressure sensor measurements; (iii) an excitation source for generating a dynamic volume or pressure, wherein the excitation source is coupled to the speculum tip for generating the dynamic volume or pressure in the ear canal; and (iv) a controller coupled to the excitation source, wherein the controller is configured to receive the one or more pressure sensor measurements and compare the pressure measurement output waveform with the excitation source input waveform to output an exudate metric.

2. The acoustic otoscope of claim 1, wherein the controller is configured to output the exudate metric based on one or more differences obtained by subtracting a scaled pressure measurement output waveform from the excitation source input waveform.

3. An acoustic otoscope as described in claim 2, wherein the exudate metric is derived based on one or more differential values, wherein the one or more differential values ​​have an increased magnitude compared to subsequent differential values ​​following a step change in pressure or volume.

4. An acoustic otoscope as described in claim 2, wherein the exudate metric is derived based on one or more differences, wherein the one or more differences have an elevated amplitude of a low frequency pressure or volume excitation compared to an amplitude of a high frequency pressure or volume excitation.

5. The acoustic otoscope of claim 1, wherein the one or more differences are averaged over at least 4 acquisition cycles.

6. The acoustic otoscope of claim 2, wherein the scaled pressure measurement output waveform includes a scaling factor wherein a midpoint value of the one or more pressure sensor measurements is substantially equal to a midpoint input value of the excitation source input waveform.

7. The acoustic otoscope of claim 1, wherein the excitation source input waveform is sinusoidal.

8. The acoustic otoscope of claim 1, wherein the excitation source input waveform is trapezoidal.

9. The acoustic otoscope of claim 7, wherein the sinusoidal excitation source input waveform and the pressure measurement output waveform are collected at several frequencies to determine a corner frequency.

10. The acoustic otoscope of claim 9, wherein the exudate metric comprises a comparison of the corner frequency to a threshold frequency corresponding to one or more of a normal tympanic membrane, viral fluid adjacent to the tympanic membrane, or mucoid fluid adjacent to the tympanic membrane.

11. The acoustic otoscope of claim 1, wherein the excitation source comprises a movable diaphragm, a movable piston, or a differential pressure source coupled to the speculum tip via a hose.

12. The acoustic otoscope of claim 1, wherein the excitation source comprises a diaphragm or a piston enclosed in the speculum tip or speculum tip holder.

13. The acoustic otoscope of claim 1, wherein the excitation source is coupled to a higher or lower air pressure source through one or more valves controlled by an excitation input.

14. An acoustic otoscope, comprising: a speculum tip configured to form a seal when inserted into the ear canal; an excitation source coupled to the speculum tip and configured to adjust pressure within the ear canal; a pressure sensor coupled to the speculum tip and configured to measure the pressure within the ear canal; as well as a controller coupled to the pressure sensor and configured to (i) generate an excitation source input waveform and (ii) receive a pressure measurement output waveform; Wherein the controller is configured to simultaneously compare the pressure measurement output waveform with the excitation source input waveform to form an exudate metric.

15. The acoustic otoscope of claim 14, wherein the excitation source is configured to cause a volume change or a pressure change in the ear canal.

16. The acoustic otoscope of claim 14, wherein the excitation source is a moving diaphragm.

17. The acoustic otoscope of claim 14, wherein after establishing a monotonic sequence of first, second, and third thresholds, the exudate metric is used to detect a non-diagnostic speculum tip leak when: (i) when the pressure measurement to excitation waveform transfer function is below said first threshold; (ii) when the high frequency transfer function of the pressure measurement to the excitation waveform is below the third threshold; (iii) when a negative pressure response is detected where the excitation source is a volume regulating piston or diaphragm returning to its original position; or (iv) When no change in the pressure measurement is detected in response to the excitation waveform.

18. The acoustic otoscope of claim 14, wherein the excitation source input waveform is a sinusoidal curve and the exudate metric is based on a frequency response function The corner frequency in , where: ΔP(f) is the pressure amplitude at multiple discrete frequencies; ΔV(f) is the volume excitation amplitude at multiple discrete frequencies; The corner frequency is when the response function is less than the value at higher frequencies. The frequency f at time.

19. An acoustic otoscope as described in claim 14, wherein the excitation source input waveform is a trapezoidal waveform, and the exudate measure is based on the difference between the excitation source input waveform and the pressure measurement output waveform, and wherein the pressure measurement output waveform is scaled to the midpoint of the excitation source input waveform.

20. The acoustic otoscope of claim 19, wherein the midpoint is the earliest time point at which the slope of the pressure measurement output waveform changes to 1 / 4 or less of its initial value, or is a half-interval point, whichever occurs first.

21. The acoustic otoscope of claim 20, wherein the exudate metric is based on a maximum amplitude of the difference waveform prior to the midpoint.

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