A METHOD AND APPARATUS FOR EUSTACHIAN TUBE DYSFUNCTION ASSESSMENT

Abstract

This invention is about an apparatus and method for positive identification of patients suffering from Eustachian Tube Dysfunction ailment. Eustachian Tube dysfunction is a common ailment which almost 1% of world population suffers. Recent clinical study indicated that some of the Eustachian Tube Dysfunction cases are due to lack of synchronization and synergy of the two muscles responsible for opening Eustachian Tube. The invention teaches a device and method for assessment of Eustachian Tube Dysfunction and identifies patients where dysfunction problem originate from lack of muscle synchronization.

Claims

1. A system for diagnosis of Eustachian Tube Dysfunction ailment, the system comprising: a probe assembly adapted to connect to one or more Eustachian tube related muscles locally over skin inside palatal area, a set of one or more sensors to detect opening of Eustachian tube, a data acquisition unit with one or more signal conditioners to condition incoming and outgoing signals, a processing computer in communication with the data acquisition unit wherein the processing computer executes a software to control operation of the system, a set of one or more sensors to measure nasal pressure; and a pressure generator to increase pressure inside nasal cavity.

2. The system according to claim 1 wherein the probe assembly adapted to connect to one or more Eustachian tube related muscles locally over skin inside palatal area comprises one or more electrodes selected from a subdermal electrode, a surface electrode, an intramuscular electrode, an intraneural electrode, an optical electrode, an optical probe, or a combination of the foregoing electrodes and probes.

3. The system according to claim 1 wherein the set of one or more sensors to detect opening of Eustachian tube comprises one or more sensors selected from a pressure sensor, a distance sensor, or a combination of the foregoing sensors placed on external ear canal of patient.

4. The system according to claim 1 wherein the data acquisition unit with one or more signal conditioners to condition incoming and outgoing signals comprises one or more subsystems to generate outgoing electrical pulses, optical pulses and one or more subsystems to condition incoming electrical pulses, optical pulses or a combination of the foregoing subsystems.

5. The system according to claim 1 wherein the set of one or more sensors to measure nasal pressure comprises one or more pressure sensors selected to be placed nasally to nose, orally to mouth, on a mask covering mouth or a combination of aforementioned locations.

6. A method for diagnosing Eustachian Tube Dysfunction problem by utilizing Eustachian tube muscles comprising a Tensor Veli Palatini muscle, a Levator Veli Palatini muscle and a Tympanic membrane, the method comprising: increasing pressure inside nasal cavity, applying stimulation pulses to one or more Eustachian tube muscles using a probe assembly, monitoring sign of movement of Tympanic membrane; and in case no movement of the Tympanic membrane is observed, repeating the foregoing steps after changing stimulation pulse parameters of the Tensor Veli Palatini and the Levator Veli Palatini muscles.

7. The method set forth in claim 6, wherein increasing pressure inside the nasal cavity is achieved externally by external pressure generator.

8. The method set forth in claim 6, wherein increasing pressure inside the nasal cavity is achieved by patient performing Valsalva maneuver.

9. The method set forth in claim 6, wherein the stimulation pulses are applied to one or more Eustachian tube muscles using the probe assembly electrically.

10. The method set forth in claim 6, wherein the stimulation pulses are applied to one or more Eustachian tube muscles using the probe assembly optically.

11. The method set forth in claim 6, wherein monitoring sign of movement of Tympanic membrane is done by external ear canal sensors.

12. The method set forth in claim 6 wherein in case no movement of the Tympanic membrane is observed, repeating the foregoing steps after increasing amplitude of the stimulation parameters to Tensor Veli Palatini muscle, Levator Veli Palatini muscle or both.

13. The method set forth in claim 6 wherein in case no movement of the Tympanic membrane is observed, repeating the foregoing steps after increasing duration of the stimulation parameters to Tensor Veli Palatini muscle, Levator Veli Palatini muscle or both.

14. The method set forth in claim 6 wherein in case no movement of the Tympanic membrane is observed, repeating the foregoing steps after increasing the difference between starting time of the stimulation to Tensor Veli Palatini muscle and the Levator Veli Palatini muscle.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0019] FIG. 1 shows location of Eustachian tube muscles mTVP and mLVP as it is seen from the mouth of the patient. This the location where the signals are picked up and stimulation is applied;

[0020] FIG. 2A shows the neurological signals mLVP and mTVP of a subject with healthy Eustachian tube activity;

[0021] FIG. 2B shows the neurological signals mLVP and mTVP of a subject with dysfunctional Eustachian tube;

[0022] FIG. 3 shows functional block diagram of the Eustachian tube dysfunction assessment device;

[0023] FIG. 4A shows a patient during assessment test with sensors and electrical stimulation leads connected;

[0024] FIG. 4B shows a patient during assessment test with sensors and optical stimulation leads connected;

[0025] FIG. 5 shows the software flow chart of the operation of the device;

[0026] FIG. 6 shows shape of signals applied to mTVP, mLVP to stimulate the muscles;

[0027] FIG. 7 shows the output of the sensor reading indicating Eustachian tube activity when muscles of Eustachian tube are stimulated electrically or optically.

DESCRIPTION

[0028] The operation of the present invention will now be described with the aid of the figures. The purpose of the invention is to diagnose the Eustachian tube dysfunction cases and identify the ones that are suffering because of neurological disorder of Eustachian tube (ET) muscles. As it is explained in the background section of this document, so far Eustachian tube dysfunction (ETD) ailment has been an ill-defined condition with little knowledge about the underlying cause. The invention is intended to diagnose ETD condition in patients and identify the category of patients who have healthy ET muscles and ET valve mechanism, but suffering from ETD because of disorder of neurological signals received by the muscles. Identification of these patients is important because these patients may benefit from neurological therapy. The invention does this by stimulating Eustachian tube muscles of the patients while monitoring pressure in the external ear canal. Stimulation is done from an easily accessible and identifiable location without causing excessive pain or discomfort to patients. FIG. 1 shows electromyography (EMG) signal pick up locations for Levator Veli Palatini muscle (mLVP) 10 and Tensor Veli Palatini muscle (mTVP) 12. Number 15 shows the location of Hamulus Pterygoids which is not apparent visibly inside the mouth of the patient, but palpable by experienced physicians. Identification of location of Hamulus Pterygoids is important for accurately locating mLVP and mTVP muscles.

[0029] The amplitude, periodicity and phase difference between the two signals received from locations 10 and 12 tell important information about the health of Eustachian tube activity. FIG. 2A shows activity of healthy Eustachian tube signals, mLVP signal (20) and mTVP signal (30) as they are observed on a computer screen. In healthy subjects with no ETD symptoms, signal 20 is observed to be bigger in signal amplitude than signal 30, and signal 20 always starts before signal 30. FIG. 2B. shows mLVP and mTVP signals for an ETD case where mTVP signal 30 is bigger in signal amplitude than mLVP signal 20 and signal 30 starts before signal 20. This is a neurological disorder. Clinical trials indicated that at least some of the ETD cases is related to this type of neurological disorder. Clinical study indicated that when this type of patients are stimulated by a 0.02 msec. duration external pulses with 0.2 mV amplitude, the Eustachian tube of the patient opens. This is an indication that this type of patients have intact muscular system and likely to respond to neuromodulation therapy for curing the ailment. It is the objective of this invention to diagnose and identify this kind of patients.

[0030] FIG. 3 shows the main components of the invention. EMG signals mLVP and mTVP are received from the patient and connected to block 110 through probe assembly 105 which receive and amplify the mLVP, mTVP EMG signals. Block 110 is an incoming signal conditioner that amplifies mLVP, mTVP signals. Block 120 is an outgoing signal conditioner used for generating external stimulation pulses to open the Eustachian tube. Block 130 is another outgoing signal conditioner that generates optical pulses to stimulate the muscles. The blocks 110, 120 and 130 are connected to data acquisition block 140 which converts received signals into digital form and give it to block 180 which is the Computer. Block 190 is software and controls the actions of the instrument. Block 150 is a pressure generator which provides low pressure air required for the testing process. Block 160 is a nasal pressure sensor which measures the pressure inside nasal cavity. Block 170 is external ear canal sensor placed in the ear of the patient.

[0031] FIG. 4A shows the connection of the EMG electrodes and sensors to the patient during a typical diagnostic session. Number 105 shows probe assembly with mLVP and mTVP subdermal electrodes together with the reference electrodes. Number 170 is the external ear canal sensor and number 160 is the nasal pressure sensor. 140 is the data acquisition system where the probe assembly 105 is connected via signal conditioner blocks. Computer 180 and the software 190 together controls the stimulation pulses and monitors external ear canal sensor 170 and nasal pressure sensor 160 to assess the dysfunction level.

[0032] FIG. 4B shows another embodiment of the invention where optical stimulation is used for stimulating mTVP, mLVP muscles instead of subdermal EMG stimulation electrodes. Optical nerve stimulation is an alternative way of stimulating muscles and it is well known by specialists. It is especially useful for patients with needle phobia who have needle anxiety. Number 135 indicates optical stimulation probes used for mLVP and mTVP stimulation. The figure also shows an alternative way of measuring pressure through mask 165 which covers both nose and mouth of the patient. Nasal pressure sensor 160 is installed on the mask 165. Yet another alternative method is placing the pressure sensor 160 in the mouth of the patient while patient keeps the mouth closed.

[0033] FIG. 5 shows flowchart of the operation of the invention. Diagnosis and assessment operation starts by computer reading electrical signals coming from mLVP and mTVP electrodes while patient is at rest. Block 210 shows where reading and recoding the mLVP, mTVP signals is done for minimum of 150 seconds. The reading and recoding activity can extend up to 300 seconds. As a next step, the recorded signals are displayed on the computer screen in block 220.

[0034] In another embodiment of the system reading signals (210), and displaying signals (220) may be omitted and operation of the system may start from block 230 directly.

[0035] In the next phase of the assessment, pressure generator is started (230) and maximum of 50 daPa pressure is applied to nasal cavity of the patient through nasal pressure sensor pathway. Pressurization of nasal cavity continues until pressure reaches 50 daPa (240). 50 daPa pressure level is considered mild pressure level which is tolerable by most patients. In another embodiment of the system, the pressure level may be adjustable for those patients who may find 50 daPa uncomfortably high.

[0036] As a next step, the stimulation pulses are applied to the patient in block 250. Stimulation is given either electrically or optically to mLVP and mTVP muscles. As a first step, only mTVP muscle is stimulated with electrical signal of 0.2 mV amplitude pulse with 0.020 msec. duration. During the application of the pulse, external ear canal sensor output is monitored. Opening of ET is seen as a distinct change in the output of external ear canal sensor output with at least 10 daPa pressure change (270). If the pressure change in not observed, the stimulation step is repeated after changing parameters (280). During this step, both mLVP and mTVP are stimulated by 0.2 mV pulses while mLVP receives longer duration pulse which lasts 0.040 msec. while mTVP receives 0.020 msec. duration pulse. The mLVP muscle stimulation pulse is applied 0.020 msec. before the mTVP pulse is applied. During the stimulation, the external ear canal sensor is monitored again for at least 10 daPa pressure change. If no pressure change is observed, the signal amplitude is increased to 0.3 mV and stimulation is repeated. Although these are the recommended parameters based on the clinical trials, in another embodiment of the invention, the pulse amplitude and pulse duration is made adjustable for finding the best pulse pattern for the patients. Block 260 shows the step where the test results are displayed.

[0037] FIG. 6 shows the shape of the stimulation pulses applied to mLVP and mTVP muscles. In FIG. 6, axis 480 shows time in Seconds and axis 490 shows signal amplitude in Volts. Item 440 is mTVP pulse which starts at 450, lasts for 0.020 seconds and finishes at 470. The amplitude of the signal 420 is 0.2 mV. If mTVP (440) signal fails to open ET, the process is repeated with mLVP (430), then with mTVP (440) and mLVP (430) together. When both mLVP and mTVP stimulated together, starting time 435 of mLVP should be before the starting time 450 of mTVP. In the FIG. 460 is the finishing time of mLVP signal. 410 and 420 show signal amplitude of mLVP and mTVP signals.

[0038] The ETD assessment of the patient is based on the results of the aforementioned test results. [0039] The following are the assessment categories: [0040] Type 0: ET does not open under no circumstances after all test patterns, [0041] Type 1: ET opens without external stimulation [0042] Type 2: ET opens with only mTVP stimulation with minimal pulse parameters, [0043] Type 3: ET opens with both mLVP and mTVP stimulations with minimal pulse parameters, [0044] Type 4: ET opens with both mLVP and mTVP stimulations with increased pulse parameters.

[0045] Medical interpretations of these types are beyond the scope of this document but they broadly define the ETD assessment level.

[0046] FIG. 7 shows the type of pressure change expected in external ear canal sensor output during opening of ET. Vertical axis 300 shows the pressure in daPa range, while horizontal axis 330 shows time scale. Item 310 shows the instant of ET opening at time indicated by 320. Normally 320 is the time of application of the stimulus when pressure change (AP) of at least 10 daPa is observed.