WO2020100155A1 - Dispositif audiomètre portatif et procédé associé - Google Patents

Dispositif audiomètre portatif et procédé associé Download PDF

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Publication number
WO2020100155A1
WO2020100155A1 PCT/IN2019/050201 IN2019050201W WO2020100155A1 WO 2020100155 A1 WO2020100155 A1 WO 2020100155A1 IN 2019050201 W IN2019050201 W IN 2019050201W WO 2020100155 A1 WO2020100155 A1 WO 2020100155A1
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WO
WIPO (PCT)
Prior art keywords
audiometer
test
hand held
audio
subject
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PCT/IN2019/050201
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English (en)
Inventor
Dr Amrit DIXIT
Original Assignee
Dixit Dr Amrit
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
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Application filed by Dixit Dr Amrit filed Critical Dixit Dr Amrit
Publication of WO2020100155A1 publication Critical patent/WO2020100155A1/fr

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    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B5/00—Measuring for diagnostic purposes; Identification of persons
    • A61B5/12—Audiometering
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B2560/00—Constructional details of operational features of apparatus; Accessories for medical measuring apparatus
    • A61B2560/02—Operational features
    • A61B2560/0204—Operational features of power management

Definitions

  • the present invention relates to a hand held apparatus for checking the hearing capabilities of a person. More particularly, the present invention relates to a low cost architecture of Audiometer by use of differential pressure sensor and thin film structure with increased accuracy using DSP controllers.
  • a skilled operator adjusts and controls the audiometer system, thereby sending different types of audio signals either through earphones, loudspeakers or bone vibrators, to a subject who is commonly sitting in a quiet room (sound treated).
  • the subject is requested to provide a response whenever he/she hears the sound on the test ear, either by activating a switch connected to a pilot light, or by raising his hand or by any other visible or audible means.
  • the audiologist or the operator looks for the response of the subject. The procedure is followed for all the frequencies and responses are noted down as thresholds of hearing.
  • the audiometer presents to the subject automatically changing tone frequencies while the intensity of the signal is controlled by the subject by means of a push button switch activating a motor controlling the motion of an intensity attenuator.
  • the subject responses are also automatically recorded by means of a writing pen moving over a chart as the test progresses. While the Bekesy method is considered by those skilled in the art of audiology as a major advance, it still requires the presence of a skilled operator and the use of rather sophisticated mechanical systems [US Patent 4,107,465]
  • An improved computerized audiometer for testing the hearing of one or more of a variable number 40 of people at the same time and generating programming for a programmable hearing aid is provided [US Patent 4,489,610]
  • the audiometer includes at least one head set and control switch for use by the person being tested, a tone generator for applying a selected sequence of tones of varying frequency and amplification to the head set under the control of a central processing unit, a memory for storing the results of the test for analysis by the central processing unit, and output means adapted to program a hearing aid in accordance with the results of said analysis when coupled thereto.
  • the tone generator may be adjustable to reflect the results of such feedback.
  • the audiometer may be under the control of an operator provided with a display and keyboard coupled to the central processing unit. Local and remote printers, data storage and modem devices may be provided [US Patent 4,489,610] This system is having a number of features which are required in audiometric devices but the device is too much bulky and not easy to operate.
  • a combination otoscope and audiometer provided with conventional lighting means and an unobstructed viewing passage for visually inspecting the ear canal of a subject.
  • the hand held instrument is also provided with a calibrated electronic circuit that automatically produces a sequence of tones of different frequencies and intensities, together with means for transmitting these tones to the subject ear.
  • the circuit includes timing means for precisely controlling the duration of each tone. Neither the production of the tones nor the duration thereof is under the control of the operator.
  • the exterior of the instrument is provided with indicators in the form of light emitting diodes to tell the operator when each tone is being transmitted to the subject ear [U.S. Patent No. 4,567,881]
  • the device is good for initial inspection of the ear canal and ear screening. It will not provide complete audiometer functions as required.
  • a test probe for impedance audiometer is discussed which is used for hearing loss.
  • a hearing testing method permits the testing of infants and others who cannot respond and provides an accurate and rapid test for others.
  • a group of pure tones at selected amplitudes and frequencies is played, through earphones, to a subject.
  • Electrodes connected to the subject head detect the subject brainwaves which are evoked responses to those tones.
  • the brain waves are amplified, averaged according to the tone frequencies, automatically analysed on a statistical basis using the’t’ test, and used to display a profile of the subject hearing ability [U.S. Patent No. 3,799,146]
  • the device is based on the response coverage from the brain waves. The accuracy depends on the signal generated by the nerve system on playing of pure tones on the ear.
  • An evoked response audiometer in which the subject is presented with a continuous auditory signal which is amplitude modulated and the evoked brain potentials of the patient (EEG) are recorded. The potentials are amplified and filtered and are averaged over a number of sampling periods to improve the signal to the noise ratio. The averaged signals are then analysed to determine the amplitude and phase of the main components of the response to determine whether phase locking has occurred. The phase of the main components is then plotted against variation of the modulating frequency and the gradient of the plot provides the latency of the response from which neurological and other factors of significance to the hearing of the subject may be determined.
  • the sound pressure level of the auditory signal is also varied and the amplitude and phase of the response plotted against these changes to provide an indication of the sensitivity of the hearing of the subject
  • US Patent No 4,462,411 The device is similar to the above device where the brainwaves are analysed to get the response of the subject. Again it can be said that the response may be false because of the unknown nature of the signals generated in the brain. One can falsely detect the signal and correlate with the audiometric function and the result may vary.
  • a further method of auditory testing has been proposed in which a computer is used to present the tones to the subject in a programmed sequence and record his responses.
  • a computer is used to present the tones to the subject in a programmed sequence and record his responses.
  • U.S. Pat. No. 3,809,811 and Canadian patent 950,106 In this type of instrument, the triggering of different intensities and frequencies by the programming circuit is entirely dependent upon the feedback from the subject responses, through his actuation of a“YES” button, but calling for a relatively complex electronic circuitry.
  • An interface for providing an appropriate dynamic range for audiometric testing comprising:
  • This device operates over wireless control.
  • the architecture of the device is bulky in nature and cannot be taken out easily. The wireless controls for this type of sensitive testing may not be appropriate.
  • a home hearing test for use with a conventional home audio system comprising an audio player and a set of headphones connected to the audio player.
  • the home hearing test includes an audio medium such as a compact disc playable in the audio player and containing a calibration tone recorded at a predetermined decibel level and a number of pre-recorded sequences of tones. Each sequence has tones recorded at different decibel levels and decreasing by a step value.
  • the home hearing system includes a calibration device for calibrating the output of the audio system to the ears of a person wearing the headphones against the predetermined decibel level of the calibration tone [US Patent 5,928,160]
  • the audio range provided by the device for audiometer testing is very limited and the functions available are very less.
  • the device is to perform hearing test or audiometry and a method for identifying
  • Audiometer systems which are available in the market are bulky and costly. There are models which are cheaper but they have very less features. A good Audiometers is the one which provides a rapid result or real time results, graphical displays showing the input and output waveforms like differential pressure curve, expiration volume time curve and flow volume loop. These features are very necessary for the medical professional to understand the typical conditions of the subject. In the medical field it is prominent that the cost of the device decides the reach of the device to common man. Hence it is a major requirement to bring the cost down so that more number of people can get diagnosed easily.
  • the primary object of the invention is to reduce the complex architecture of Audiometer by using differential pressure sensor and thin film structure.
  • Another object of the invention is to provide a hand held Audiometer which is light weighted and easy to operate.
  • Another object of the invention is to provide a hand held Audiometer at a lower cost with high accuracy using DSP controllers.
  • Hearing is important. It is the sensory channel by which we are connected to other people, warned of impending dangers, and entertained by music and laughter. Good hearing enables us to perceive the laughter of friends, the cries of a baby, and the breeze rustling through the trees. Without it, we feel isolated from the world round us, and frustrated by our inability to fully understand the flurry of activity that surrounds us. Man is a social creature, and hearing is critical to his ability to function as such.
  • Audiometry is performed to check the status of an individual’s hearing and identify the type and amount/ degree of hearing loss if any. The conditions mentioned below may cause hearing impairment.
  • Audio-logical investigations help us to diagnose the nature of deafness and localize the site of disorder.
  • the method by which subject hearing sensitivity can be determined is termed as audiometry.
  • auditory stimuli with varying intensity levels are presented to the person who responds to these stimuli.
  • the minimum intensity level of these stimuli to which consistent responses are obtained is taken as the threshold of hearing.
  • the subject hearing sensitivity can be estimated by obtaining an audiogram.
  • An audiogram is a plot of threshold intensity versus frequency. Then the best- suited medical/ surgical treatment or hearing aid / assistive devices can be prescribed.
  • This disclosure aims to provide a hand held light weight device for performing the hearing test at an affordable price.
  • a hand held audiometer for detecting a hearing loss of a person, comprising a power supply; a keyboard control unit including a keypad for input signals; a subject response controller including a push button component in order to provide input subject response; a sine wave generator configured for reference sine wave generation; an audio amplifier and attenuator configured to control the amplitude of the pure tone sine wave; a display control block for controlling a graphical display; a test selection mode configured for selection control for the air and bone conduction test; an air conduction means transmission of the pure tone audio signal to air conduction headphones; a bone conduction means for a bone vibrator and a microcontroller including audio peripherals i.e. microphone and audio DAC with speaker and their individual controls configured for controlling the pure tone wave generation with different frequencies and amplitudes and also to perform audiogram test.
  • a keyboard control unit including a keypad for input signals
  • a subject response controller including a push button component in order to provide input subject response
  • a sine wave generator configured for reference sine wave generation
  • Figure 1 illustrates a Block Diagram of audiometer in accordance with the present invention
  • Figure 2 illustrates an Audiogram for the test (AC) in accordance with the present invention
  • Figure 3 illustrates an Audiogram for the test (BC) in accordance with the present invention
  • Figure 4 illustrates an Experimental circuit arrangement for Signal generation & Audiogram in accordance with the present invention
  • Figure 5 illustrates a Flow Chart of the Working of presented audiometer in accordance with the present invention
  • Figure 6 illustrates an Audiogram Framework in accordance with the present invention
  • Figure 7 illustrates a 4x4 Matrix keypad Layout in accordance with the present invention
  • Figure 8 illustrates a Front Panel of the Audiometer Device in accordance with the present invention
  • Figure 12 is a photographic representation of a Complete Audiometer in accordance with the present invention.
  • Audiometer and Hearing Test Audiometer is used to measure the ability of a subject to hear at specific frequencies. Fundamental to this measurement is pure tone measurement. The audiometer is used to generate pure tone signals at specific frequencies within the 250 Hz to 8 kHz range. For each frequency the level of loudness is incremented from soft to loud. The subject is asked at which point he/she starts to hear the sound, which will then represent the subject hearing threshold at that frequency. The final result is plotted as an audiogram that will be interpreted by medical professionals to determine proper treatments.
  • the hearing threshold is frequency dependent. Hence, SPL corresponding to a given HL varies with frequency. Intensity levels in audiometers are indicated in HL. Table 1 gives the dB SPL (dB HL) threshold values of a normal person for standard frequencies. The "0 dB" hearing level in audiometry is a modal value derived from a large population of normal persons. Normal values for auditory thresholds were defined by the International Standards Organization (ISO) in 1984. These values are derived from large population studies of normal adults 18-30 years of age. The following table gives the dB SPL values corresponding to 0 dB HL for standard frequencies.
  • ISO International Standards Organization
  • An audiogram is a plot of threshold intensity versus frequency.
  • the intensity scale in HL increases downwards, and hence the audiogram resembles like an attenuation response, a lower point on the audiogram indicating higher loss.
  • a typical audiogram (dB HL vs. frequency graph) comparing normal and impaired hearing is shown in Fig.3.
  • the dip or notch at 4 kHz, or at 6 kHz signifies noise-induced hearing loss.
  • HL denote louder threshold levels. Those above 0 dB HL are expressed in negative decibels and are less intense.
  • An audiogram comprises of four separate curves. They are right ear air conduction (AC), right ear bone conduction (BC), left ear AC, and left ear BC. The symbols used on most audiograms are X - left air conduction, O - right air conduction.
  • the objective of the invention is to develop a low cost hand held audiometer device which will work in conjugation with the hearing aid.
  • the audiometer will use the audio capability of the hearing aid to generate pure tone sine wave and perform hearing test. This will reduce the hardware requirement for dedicated audiometer setup and PC etc.
  • the audiometer device is having a 2.4” TFT screen for displaying the audiometer setup, control and audiogram.
  • the device is having a 3*4 matrix keypad to provide the control facility for hearing test.
  • a response switch is provided to collect the subject hearing response.
  • the power supply is to provide the power to the device. It may be a battery connection, power bank, USB connection from the PC etc. The input required is 5V supply. Power control section controls the different peripherals connected to the systems like graphical display, keyboard, subject response circuitry, audio amplifier and attenuation circuitry etc.
  • the keyboard control includes the keypad input buttons which is used for the audiometer control. It enables the user to control the audiometer functions for hearing test.
  • the input selection includes start of test, selection of amplitude, frequency, air conduction test, bone conduction test, right and left channels, data locking and print etc.
  • the subject response controller is a circuitry which is having a push button component used for the indication of the subject response while listening to the pure tone.
  • the LED light connected to the subject response controller get ON’ and when the switch is released the LED OFF’ condition occurs.
  • Sine wave generator is responsible for the reference sine wave generation. This will be sent for the pure tone with selected amplitude and frequency. Similarly the noise generator circuit will generate the noise if required.
  • Audio amplifier and attenuator control the amplitude of the pure tone sine wave.
  • Air conduction means transmission of the pure tone audio signal to air conduction headphones.
  • SD Card Interfacing [0073] The present hand held audiometer is equipped with SD card module which stores the tested data in text file (.txt). Once the testing for air conduction (AC) and bone conduction (BC) for both the ear are performed, the amplitude points are generated on screen simultaneously. The audiogram is generated and displayed on TFT screen when one presses the‘print’ button; the audiogram data for AC and BC are saved in the SD card attached with the audiometer. The audiogram of every test is appended in the same text file.
  • AC air conduction
  • BC bone conduction
  • the audiometer is battery operated.
  • the hand held device is useful for portability.
  • the device can be taken out for hearing test very easily. It can be used with the external power source like USB adapter, Mobile charger etc., and simultaneously with the internal battery power.
  • the on/off switch is provided so as to switch on/off the audiometer when required.
  • Microcontroller is the main component of the whole assembly.
  • the microcontroller controls the above activity. All the programming is done onto the microcontroller.
  • the communication to display in the graphic control, audio control, amplitude control etc. is sent by microcontroller.
  • the features of the microcontroller are listed in the below sections. Similarly the various features of audio control are also discussed in the sections below.
  • the head phones are placed over the subject ears.
  • the Pure-tones are presented to one ear at a time.
  • the other ear will be isolated from the test ear.
  • the test will be done between 250Hz to 8kHz range of audio frequency. Whenever subject will hear the beep sound, he will eventually press the switch. That will indicate on the audiometer device by blinking of LED. So, the user or the audiologist will set that point for respective value of amplitude and frequency.
  • The‘X’ for left ear in blue color and ⁇ ’ for right ear in red color is marked against the threshold levels of the subject. If there is a difference of more than 40dB in two ears, the better ear is masked to rule out its participation and the masked thresholds across the frequency range are obtained for the poorer ear.
  • Bone Conduction 1BQ Bone Conduction 1BQ
  • the microcontrollers used for the audiometers are based on an atmel atmega256. It has 54 digital input/output pins (of which 15 can be used as PWM outputs), 16 analog inputs, 4 UARTs (hardware serial ports), a 16 MHz crystal oscillator. It contains everything needed to support the complete system.
  • Another microcontroller used for the audio control is STM32F4.
  • This board is equipped with audio peripherals i.e. microphone and audio DAC with speaker. All the audio related works are performed in this. Pure tone wave generation with different frequencies and amplitudes are covered in this. The communication from Atmel microcontroller for different instructions to perform audiogram test is implemented in it.
  • Figure 4 shows the experimental setup of the audiogram development. It consist of microcontroller development board, amplifier stage, interrupt switch for user response and earphone of 10 ohm impedance and 108 ⁇ 4dB /mW sensitivity.
  • FIG. 5 illustrates the flow chart of the functioning of the audiometer programming. Audiogram Display Framework
  • the audiometer display is shown in the figure 6.
  • the status of the selected pure tone can be seen. i.e. air conduction/ bone conduction, right/ left channel, amplitude levels in dBHL, frequency component being played, tone on/off signal and finally audiogram. This will help the user/ audiologist to recognize the state of the audiometer and can control accordingly.
  • the manual mode of operation is implemented with the help of 4x4 keypad.
  • the figure 7 displays a logical implementation of various functions on keypad.
  • the device performs different task according to the key pressed. Various factions of the key are described below:
  • Step 1 Make connections of board. Connect to power supply. Plug the headphone and subject response switch.
  • Step 2 Place the headphone to ear of the subject. Instruct the Subject. Inform about switches to subject. Start with 1000Hz at 40dBHL right ear if there is no better ear. The sequence should be 1000, 2000, 4000, 8000 and recheck at 1000, 500, 250 Hz respectively.
  • Step 3 Power ON the switch and press start button of keypad.
  • the air conduction sound on 250Hz at OdBHL will start to play on right ear when the user/ audiologist press the ON button.
  • Step 4 Ask the subject if he is able to hear the tone and give response by pressing the switch once start to listen the tone.
  • Step 5 If there is no response from the subject then press the Amp+ switch to increase the amplitude level and check for the subject response.
  • Step 6 Repeat the process till the subject is able to hear the signal/tone.
  • Step 7 Once the response is obtain then again check the hearing level by pressing the Amp- key to confirm the hearing level.
  • Step 8 If the audiologist is satisfied with the subject response then lock the data by pressing Lock key. The data will be recorded and plotted over TFT.
  • Step 9 Now press the Freq+ to change the frequency and shift to the other frequency and again repeat the above process.
  • Step 10 Once all the frequency data is collected then ask the subject to put earphone on left ear. And press the ACL key on keypad.
  • Step 11 Now again perform the above steps for the left ear hearing levels. Once all the frequency data are recorded change the headphone and put the bone conduction vibrator. Step 12: Similarly perform the above test as per the recommendation and lock the thresholds levels for different frequency and ear.
  • Step 13 After the completion of the test press the print button to generate the audiogram image in the TFT display.
  • the test can be performed as per the requirement of the user/ audiologist.
  • the sequence of testing etc. is on manual control.
  • the final output the invention is a low cost, handheld audiometer.
  • the invented audiometer will provide the rapid result of hearing test thresholds level of air conduction and bone conduction.
  • the invented device shows the result on the color graphical display.
  • the generated audiogram is shown with the required symbols.
  • the severity in terms of nerve degradation and types of the diseased can be recognized by the device.
  • the device is easy to handle and operate.
  • the structure and functionality is very simple and can be operated by a person having education up to high school after basic training.
  • the cabinet is made in such a way that it can be handled and made portable easily.
  • the local battery setup is provided to power the audiometer standalone. It can also be connected to power bank, Personal Computers and power adapter.
  • Figures 8 and 9 shows the front panel of the audiometer and complete audiometer system.

Abstract

L'invention concerne un audiomètre portatif, comprenant une alimentation électrique ; une unité de commande par clavier comprenant un pavé numérique pour des signaux d'entrée ; un dispositif de commande de réponse de sujet comprenant un élément de bouton-poussoir afin de permettre l'entrée de la réponse de sujet ; un générateur d'onde sinusoïdale configuré pour générer une onde sinusoïdale de référence ; un amplificateur et un atténuateur audio configurés pour commander l'amplitude de l'onde sinusoïdale de tonalité pure ; un bloc de commande d'affichage pour commander un affichage graphique ; un mode de sélection de test configuré pour une commande de sélection pour un test de conduction aérienne et osseuse ; une transmission de moyen de conduction aérienne du signal audio de tonalité pure à des écouteurs à conduction aérienne ; un moyen de conduction osseuse pour un vibreur osseux et un microcontrôleur comprenant des périphériques audio, c'est-à-dire un microphone et un CNA audio pourvu d'un haut-parleur et leurs commandes individuelles configurées pour commander la génération d'onde de tonalité pure à différentes fréquences et amplitudes et également pour effectuer un test d'audiogramme.
PCT/IN2019/050201 2018-11-16 2019-03-13 Dispositif audiomètre portatif et procédé associé WO2020100155A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
IN201821043305 2018-11-16
IN201821043305 2018-11-16

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WO2020100155A1 true WO2020100155A1 (fr) 2020-05-22

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Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5197332A (en) * 1992-02-19 1993-03-30 Calmed Technology, Inc. Headset hearing tester and hearing aid programmer
US20080121038A1 (en) * 2006-03-01 2008-05-29 Otovation, Llc Portable audiometer enclosed within a patient response mechanism housing

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5197332A (en) * 1992-02-19 1993-03-30 Calmed Technology, Inc. Headset hearing tester and hearing aid programmer
US20080121038A1 (en) * 2006-03-01 2008-05-29 Otovation, Llc Portable audiometer enclosed within a patient response mechanism housing

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