Classifications

• • 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
  • A61B5/121—Audiometering evaluating hearing capacity
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
  • A61B5/00—Measuring for diagnostic purposes; Identification of persons
  • A61B5/68—Arrangements of detecting, measuring or recording means, e.g. sensors, in relation to patient
  • A61B5/6801—Arrangements of detecting, measuring or recording means, e.g. sensors, in relation to patient specially adapted to be attached to or worn on the body surface
  • A61B5/6813—Specially adapted to be attached to a specific body part
  • A61B5/6814—Head
  • A61B5/6815—Ear
  • A61B5/6817—Ear canal

Definitions

• the present invention relates to a dual channel otoacoustic emission device wherein the otoacoustic emission test that is an objective measurement method of recording sounds formed spontaneously or by an audio stimulus in normal or healthy inner ears is made more functional so as to be utilized in researches in relation to auditory physiology and by using a domestic software and hardware in a different algorithm with the data which is obtained from empirical studies.
• Prior Art Sound is a mechanical wave that can spread throughout a material environment. Intensity of the sound is known as decibel, while the rate per second of a vibration is known as frequency.
• Cochlea that is our organ of hearing, codes sounds as intensity and frequency in the inner ear. This coding process is performed by the cochlea-specific cellular structures.
• Various auditory theories have been put forward in coding of the sounds depending on said cellular structures. A theory which has been already recognized by many researchers and they have compromised on is, the travelling wave theory that was suggested by Von Bekesy (travelling wave theory- The Nobel Prize in Physiology or Medicine-1961). According to this theory; the cochlea has a constant "maximum vibration level" per each audible frequency on basilar membrane.
• the field with the maximum vibration amplitude in high frequencies is basal region of the cochlea while the field with the maximum vibration amplitude in low frequencies (as the frequency of auditory energy decreases) of the basilar membrane is apex.
• Basilar membrane is stiffer and narrower in the basal region on the other hand it becomes more flexible and larger towards the apex. It has a different maximum vibration field for each frequency due to its said structural characteristic.
• Bekesy suggested that the amplitude of region with the maximum vibration is proportional to the intensity of an auditory stimulus in addition to said findings.
• Frequency selectivity of the inner ear that is the organ of hearing is described in accordance with the travelling wave theory of Von Bekesy. Studies conducted have shown that this theory has failed to fully explain frequency selectivity of the cochlea however; any other hypothesis or theory has not been put forward in order to fully explain frequency selectivity of the cochlea instead of said theory.
• the cochlea provides nonlinear responses and its sensitivity against the sounds increases as the intensity of stimuli decreases. Bekesy says depending on his observations that frequency distribution or selectivity in the cochlea is performed through the basilar membrane that shows different mechanical characteristics in the cochlea. On contrary, all cellular structures within the cochlea show different frequency-specific mechanical characteristics.
• Otoacoustic emissions are the sounds generated by the normal cochlea and can be generated spontaneously or as a response to an acoustic stimulus.
• Otoacoustic emissions are low-level sounds that are generated as a reflection of active processes in the cochlea and can be measured through the outer ear channel. They were initially defined by Kemp in 1978. It is believed that the otoacoustic emissions reflect activities of active biological mechanisms and thereby provide normal auditory fine sensitivity, sensitive frequency selection and wide dynamic range. These evidences obtained show that this mechanism (at least in mammals) is with outer hair cells. When the outer hair cells disappear or are demolished; auditory sensitivity decreases at the rate of 40-60 dB, mark of frequency selectivity curve increases or disappears, an extraordinary increase in responses to auditory stimuli and responses with stimulus level is observed.
• otoacoustic emission is generated by the vibration of the tympanic membrane and said signal can be measured with a sensitive microphone.
• Measurement of otoacoustic emissions is a sensitive indicator in assessment of peripheral auditory function. It makes possible both to determine cochlear component in hearing losses and to objectively follow the minute changes in the state of cochlea, which cannot be detected by means of other audio logical methods. These are easy and fast to apply. They can be easily tolerated by patients. They are non-invasive tests which are based on objective results. OAEs can be easily measured.
• Ail requirements consist of speakers including a microphone and providing a probe. Fine acoustic responses including OAEs are collected and displayed by a computer. OAEs are particularly preferred in auditory function researches of newborns, children, elderly, patients with severe conditions to whom ototoxic drugs are administrated, foreign language speakers and mature people who do not provide enough cooperation for subjective tests. A stimulated OEA can be recorded in all ears having normal or near-normal hearing ability. Emissions cannot be generated when outer hair ceils are structurally damaged or fail to function. Furthermore, transmission function of the middle ear is also important in terms of OAE detection. Because both the acoustic stimulus and the sounds generated by the cochlea have to pass through the middle ear.
• Stimulated otoacoustic emissions result from transient stimuli such as clicks (1 kHz-4 kHz) or tone pip-tone burst (frequency-specific). Generally, a stimulus of approx. 80 dB SPL is used. Emission responses generated by the cochlea are measured with the sensitive microphone in ear channel and averaged by being removed from background noise. Non-linear responses are considered during examination of the signals; linear response of acoustic probe and the outer ear duct is cancelled. Non-linear stimulus consists of a quadrumvirate.
• first three stimuli are presented in the same phase while the fourth one is presented in the reversed phase and as having a 3 times more amplitude relative to those of the first three ones.
• Otoacoustic emission test is a test method that can assess hearing ability of an individual in a very short time and can provide clear information about the cochlea. Therefore, it is a measurement method that has a clinically high software value and is a must for all training and research hospitals, maternities, state hospitals and medical collages.
• Otoacoustic emissions are an objective test method that provides information about the state of cochlea in the inner ear. Because the structures enclosing the organ of hearing is covered by a bone capsule, any surgical and medical intervention is performed with some limitations despite the current developing and improving technology. Clinical assessment of physiological changes in cochlea is performed with the otoacoustic emission test and thereby objective information on hearing of an individual can be obtained.
• the otoacoustic emission used with an imported software is used with a high cost in our country as a measurement method that has a clinically high software value and is a must for ail training and research hospitals, maternity facilities, state hospitals and medical colleges.
• cost is much higher. Therefore, there would be an important profit for our country if domestic software and hardware components were produced.
• the otoacoustic emissions are an objective measurement method that is clinically high-value and particularly used in newborn hearing screening processes.
• This test method can be performed through a computer together with a software and interface connections.
• This test battery is used in our country by totally being imported from abroad and with a significantly high cost.
• This is a type of device that is a sine qua non requirement in all institutions including maternities, health research and application centers and the public hospitals union.
• These measurements can be performed in newborn hearing screening with a hierarchical organization (such as 1 st , 2 nd , 3 rd Step). It gives a very high amount when calculating the cost.
• the prior art probes which have been already used are a type of probe that can be only inserted into one ear at once, allows measuring and fails to completely fit in the ear in a stabilized manner.
• the prior art measurement method of otoacoustic emission test was used in a single channel design, in other words by making measurement first in one ear and then in the other ear.
• the present otoacoustic emission method is an objective test method that can assess hearing in a non-invasive manner.
• a sound is recorded firstly from one ear via a miniature microphone and speaker within the probe inserted in the ear and then from the other ear by inserting the same probe in the other ear.
• the sound reaches at the cochlea that is the organ of hearing within the inner ear by transiting the outer and middle ear via the speaker. Sounds reflected from the cochlea via the microphone are measured as emissions.
• Cochlea is capable of frequency-specific coding and analyzing the sound.
• Basilar membrane within the cochlea has an important role in sound coding or analysis. High-frequency sounds lead to vibrations at the end (basal), while middle frequency sounds lead to vibrations at the middle part (middle) and low frequency sounds lead to vibrations towards the last part (apex) of the cochlea.
• the sound transmitted via the speaker can be a click-stimulus type or frequency- specific. While the click stimulus only evokes a certain part (500 Hz-4000 Hz) of the cochlea, frequency-specific stimulus receives responses by stimulating each frequency region separately in a range of 1000 Hz between 10000 Hz. Click stimulus is the commonly used stimulus type and also very common in newborn hearing screening.
• Frequency-specific stimulus type (tone pip-tone burst) is a stimulus type that is typically used in clinical examinations but not used in newborn hearing screening.
• these stimulus types transmit the stimulus - high frequency sounds from the basal of the cochlea, low frequency sounds from the apex of the cochlea- and record depending on the same.
• records are taken from a limited region of the cochlea, there are some delays in responses of the stimulus or ail frequency bands within the cochlea cannot be assessed effectively.
• the otoacoustic emission device is developed by making frequency algorithm of the otoacoustic emission test that assesses hearing as an objective test method more efficient and utilizing a domestic software.
• the invention provides assessing the inner ear due to a different algorithm use, obtaining more information about the cochlea and also performing simultaneous dual ear measurement.
• the present invention relates to an otoacoustic emission device wherein auditory measurement can be performed from both ears simultaneously.
• Advantages of the present invention are as follows:
• test time is particularly important for children as the times when the children are relaxed are relatively short. Because cables of the microphone and the speaker are within a shielded channel (2A) and the device is connected to the test box by means of a connector (3A) as shown in Figure 2, drawbacks associated with cable malfunctions will be avoided.
• the device can sense different situations and display them to the user during the test time,
• the present device can immediately detect when the probe placed in the outer ear channel is displaced during testing, ambient noise is increased or the device is disconnected from the probe or the computer.
• the device can perform simultaneous dual ear testing.
• the device is operated via wireless communication. Due to the wireless communication, there will be no need for connection cables between the OAE measurement device and hardware box and thereby total cost will be reduced.
• the software of the device has mobile and desktop and also 32 bit and 64 bit versions and thereby it can be operated in different operating systems.
• Figure 1 is a block diagram of an electronic circuit board.
• Figure 2 is a design of a stethoscope-type, dual channel probe.
• Figure 3 is the software architecture.
• AD9832 Digital Signal Generator AD9832 Digital Signal Generator
• Interface module 2B.
• the test method according to the present invention comprises preparing a hardware board ( Figure 1) by registering it to perform a simultaneous measurement for both ears ( Figure 3). This method shortens the total time of testing. Test time is particularly important in newborn infants in terms of healthy measurement of hearing. As test time is longer, the test battery is affected by environmental sounds and physiological noises, whereby it gives faulty negative values since it analyzes measurements by using a sensitive microphone.
• a different design including, apart from the software, a sensitive microphone and a probe ( Figure 2) that receives measurement records from the ears via a speaker system, is provided.
• the probe of the invention except the software, is a type of probe that is inserted in both ears in a similar manner with a stethoscope ( Figure 2), which remains therein in a totally stabilized manner and is particularly advantageous in newborn hearing assessments in terms of measurement and time.
• the present device is portable and actuated via wireless communication (2) ( Figure 1), Its portable design particularly ensures in situ measurabiiity in neonatal units.
• the invention provides a record method from ail frequency bands of the cochlea with Fourier analysis ( Figure 1) together with the stimulus method based on the principal of taking records from the entire cochlea by modulating the frequency algorithm of the present test method.
• the otoacoustic emission device receives further information from the cochlea by recording the sounds from the cochlea or the inner ear.
• Logic of the changes in the software or frequency algorithm is based on that when the sound waves or waves pass from an environment to another environment having a different physical density, velocities and wavelengths of the frequencies change instead of the frequencies themselves. Therefore, different frequency algorithm of our invention ensures a more efficient performance for the otoacoustic emission test.
• a stethoscope-type probe comprising a miniature speaker that is a dual channel speaker or which can perform recording for both ears simultaneously and a microphone is used.
• Figure 1 two versions of the software of the device; including both mobile and desktop versions in 32 and 64-bits is provided.
• the present invention consists of two different parts. First one of these is the hardware and the other one is the software: 1. HARDWARE
• Communication for generating sound frequency, sensing sound signals, applying, measuring filters and transferring the data obtained to computer is provided by an electronic hardware board to be designed uniquely.
• the electronic hardware board is designed as a micro controller based integrated (3B) system.
• a block diagram of the system designed is presented in Figure 1.
• the circuit board is formed with a micro controller (3)/ two AD9832 frequency generators (5,6) controlled by a Digital Signal Processor (DSP), a LM 1972 Signal attenuator (13) and a 16 bit 50 ksps (4) Anaiog-to-Digital Converter (ADC).
• DSP Digital Signal Processor
• ADC Anaiog-to-Digital Converter
• the frequency (7-12) and the trigger signals (14,15) that are required for the test to be applied are determined by the computer software and transmitted to the micro controller (3) via communication.
• the micro controller controls desired frequencies and output power settings of these frequencies with the AD9832 frequency generators (5,6) and the LM1972 attenuator (13).
• Frequencies generated (18) are transmitted to speakers that are specifically designed on the probe (16) inserted in ears.
• the sound reflected is sensed by the microphone that is specifically arranged in the same probe (16).
• An exemplary probe is shown in Figure 2,
• the microphone which is integrated into the probe (16) senses sound signals reflected from the inner ear. Since the signals sensed by the microphone are quite weak, these signals should be amplified and also isolated from possible noises. To this aim; the signal received by the microphone is subjected to amplification (12), low pass (10) and high pass (11) filters in various orders. When the signal is prepared analogously, it is connected (3) to inputs of a high speed Analog-to-Digitai Converter (ADC). Thereby, the sound signal reflected is converted into digital signals by the micro controller (3) following its registration via ADC. Digital information obtained is transmitted to the computer through a preferred communication channel (1,2) so as to be processed.
• ADC Analog-to-Digitai Converter
• OEA software has a modular configuration and operates on a relational database. Considering these basic requirements and software experiences, optimum architecture for the software to be materialized is determined; a four- layer configuration including data access, filtering, analysis and data base is modeled. Furthermore, layers are divided into their modules according to functions of the applications. During the development process of the software, Delphi software development environment and Microsoft SQL Server relational database are utilized; by taking the current software licenses and software abilities into consideration.
• OAE software is designed in order to meet the following criteria:
• the software developed is formed of 4 main modules.
• the main architecture of the software is represented in Figure 3. for communicating with the User (IB).
• the main form is displayed on the screen when the software is started up and access to the other forms is performed on this form (3B-9B).
• Input/Output flOB ⁇ Moduie for communicating with the device and for performing of data processing. Synchronization between data and the device, data base (11B), file (12B) and reporting (13B) is performed by means of this module.
• System Objects (14B):Module for controlling the function and procedures of the entire system.
• the user is not capable of having access to this module, the module can only be accessible by using services and it operates in the background (15B, 16B).
• This module performs processes of generating graphics in the software ( ⁇ 7 ⁇ ), ensuring that the program is parallel (18B), arranging the data and organizing ail processes.
• Algorithm fl9B Module for storing and operating all mathematical algorithms. It is divided into 2 sub modules including the statistics (20) and digital signal processing (21B).
• the otoacoustic emission tests developed according to the present invention are objectively applied for individuals including newborn infants, children, the individuals whose hearing abilities should be assessed sensitively (individuals taking ototoxic drugs, individuals with sudden hearing loss, etc.), the individuals that fail to respond or give misleading results in hearing tests which are routinely conducted in health centers which have a wide institutional use and patient profile such as maternities, the public hospitals union, the health research and application hospitals, the training and research hospitals, the private health institutions and hospitals, the institutions providing audioiogy education, medicine collages.

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Publications (2)

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Family Applications (1)

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• 2016
  • 2016-12-28 TR TR2016/19885A patent/TR201619885A2/tr unknown
• 2017
  • 2017-12-20 WO PCT/TR2017/050683 patent/WO2018208266A2/en active Application Filing
  • 2017-12-20 AU AU2017413947A patent/AU2017413947A1/en not_active Abandoned

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