MXPA99000377A - Intracanal prosthesis for hearing evaluation - Google Patents

Abstract

A hearing evaluation and hearing aid fitting system (22) provides a fully immersed, three-dimensional acoustic environment to evaluate unaided, simulated aided, and aided hearing function of an individual. Digital filtering of one or more signal sources representing speech or other audio-logically significant stimuli according to selected models and digitally controlled signal processing parameters produce a simulated acoustic condition for presentation to a hearing impaired person for hearing evaluation.

Description

INTRACRANIAL PROSTHESIS FOR AUDITORY EVALUATION BACKGROUND OF THE INVENTION TECHNICAL FIELD The present invention relates to auditory evaluation and auditory adjustment of prostheses. Particularly, the present invention relates to an electroacoustic audiometer, for auditory evaluation with prosthesis, with simulated prosthesis or without prosthesis.

DESCRIPTION OF THE STATE OF THE ART The human auditory system processes sounds from a complex three-dimensional space, via the inner, middle, and outer ear, as well as via the trajectories of neuronal complexes that go to the auditory cortex within the brain. A significant percentage of the human population, particularly the elderly, is affected by measurable hearing loss due to various conductive, sensoneuronal, or auditory central disorders. Rehabilitation via a hearing aid is still the only viable option for those types of hearing impairments that can not be medically treated in any other way or cured via surgery.

Advances in hearing aids and adjustment technologies are continually being made. Currently the volume-ear hearing aids, for example the types within the canal (ITE), behind the ear (BTE), inside the canal (ITC), and completely inside the canal (CIC), have increasingly better cosmetic appearance, due to improvements in electronic and mechanical miniaturization. However, it is even more significant the increase in the capacity of the signal processing schemes of auditory prosthesis, such as filtration and multi - band dynamic compression.

Because manufacturers are continually developing new hearing aids with unique signal processing schemes, professionals who prescribe hearing aids face the difficult task of prescribing and selecting from the available selection. a hearing aid for a disabled individual. A cursory glance at the available auditory signal processing schemes reveals an impressive array of categories, sub-categories and associated acronyms that are puzzling most professionals who prescribe hearing aids (see Mueller, HG, A Practical Guide To Today's Bonanza of Underused High-Tech Hearing Products, The Hearing Journal, vol 46, vol 46, no 3, pp 13-27, 1993).

Currently, the optimal prescription of hearing aids remains a difficult goal to achieve in auditory rehabilitation. The fundamental problem is that there are a large number of electrical, acoustic and physical parameters that affect the performance of hearing aids. These parameters include signal processing schemes, electronic circuit settings, hearing aid size, depth of insertion, canal size, patient controls, lifestyle, and related factors that should be considered when prescribing and fitting a hearing aid. . These parameters of hearing aids are not only complex but highly interrelated, but they also vary according to the unique interaction of the auditory apparatus with the individual with hearing impairment.

Generally, the in situ performance characteristics of an auditory prosthesis can not be predicted with conventional adjustment methods and instrumentation. The dissatisfaction among users of hearing aids is partially due to the fact that the hearing aids are not adjusted, which is manifested by the high rate of returns, which often exceed 20%, according to industry reports.

Factors that Contribute to Unsatisfactory Results of Hearing Aids Inaccurate diagnoses by conventional audiometry. The evaluation of the ear is the first step in the prescription and adjustment of a hearing aid. An accurate evaluation of the individual's auditory function is important because the formulas that are prescribed for hearing aids depend on one or more diagnostic data (see Mueller, HG, Hawkins, DB, Northerm, JL Microphone Test Measurements: Evaluation and selection of Auditory Prosthesis, Singular Pubiishing Group, Inc., 1992: Ch. 5).

The process of prescribing hearing aids involves the transfer of diagnostic data into electroacoustic parameters of hearing aids that are used in the selection of hearing aids. Traditional hearing evaluation methods and instruments employ a variety of air conduction transducers to couple the acoustic signals within the ear.

Commonly used transducers include microphones, such as the TDH-39. TDH-49. TDH-50. hearing aids, like ER-3a. v speakers (see Audiometers specification, ANSI-S3.6-1989, American Standars National instítute). A measure of the threshold obtained with these transducers is compared with an average threshold obtained by testing a group of otoligically normal individuals. That middle threshold, by definition, is marked with the hearing volume of zero decibels or OdB HL. With this concept of zero reference, the threshold measurement of ontologically normal persons varies by 20 dB or more. These variations can be attributed to the following factors: 1. Variation due to the type of transducer used and placed in the ear.

In a study by Mowrer, et al discrepancies of 10 dB were found in 36% of the measured thresholds (see Mowrer, DE, Stearns, C, variation of threshold measurement among those who prescribe hearing aids, Auditory Instrument, vol. 43, No. 4, 1992). Another major disadvantage of the measurements obtained when using a traditional transducer is that the results are not interchangeable with the measurements taken with another transducer for a given individual (see Gauthier, EA, Rapisadri, dA, A threshold is a Threshold is a Threshold Auditory Instruments , vol.33, no.3, 1992) 2. Variation due to the calibration methods of transducers that use couplers that do not represent the human ear.

Although newly developed couplers almost achieve the acoustic impedance characteristics of an average human ear, there is still disagreement about the accuracy of the artificial ear (See Katz, J., Book of Clinical Audiology, Third Edition, 1985, pp 126 ). Most current calibration methods rely on 6-cc 0 2-cc couplers that are known to have considerable discrepancies in acoustic characteristics of the human real ear, (see specifications of audiometers, ANSI-S3.6-1989, American Standards National Institute ). Additionally, even if an agreement is reached regarding an average artificial ear, the variation between individuals is significant due to the individual acoustic characteristics of the pinna of the ear, ear canal, shell and to a lesser degree, the head, and the torso (see Mueller, HG, Hawkins, DB, Northern, JL, Microphone Medodas: Auditory prosthesis selection and evaluation. (1992, pp. 49-50) In one study, the variation among the subjects was more than 38 dB over 6 standard audiometric frequencies of sound pressure levels (SPL) in the tympanic membrane of 50 ears of 25 adults (see Valente, M., Potts, L., Valente, M., Vass. ., Variation intersubjects of Real Ear SPL: TDH-39P vs. ER-3a Hearing Aids, In press. JASA). * 3. Conventional audiometric measurement methods do not provide self-calibration means, even though the characteristics of the transducer are known due to the use or damage of the moving diaphragm.

Physicians who use regular methods can not detect gradual changes in transducer sensitivity.

Although the errors caused by the factors described above are not cumulative in all cases, the possibility of substantial errors is always present. Additionally, these errors are not consistent across all frequencies and consequently can not be simply compensated during the adjustment process via a total volume adjustment.

II.- lack of real auditory conditions in the evaluation of hearing with and without prosthesis.

Lack of Binaural Advantage Considerations.

Many studies have shown the advantage of binaural hearing over monoaricular hearing (see Cherry, EC Some Experiments on Recognizing Words with One and Two Ears, JASA, Vol 25, No. 5, 1953, pp. 975-979, Cherry, EC, and Taylor, W, K., Some Additional Experiments on Recognizing Words with One and Two Ears, JASA, Vol 26, 1954, pp. 549-554). These studies have focused on the advantages offered by the Different Binaural Volumes (BMLD) and the Difference of Volumes of Binaural Intelligence (BILD).

Recent studies of BMLD and BILD involve the presentation of signals and noise, in one and two ears in different phases. The detection of tone and intelligibility showed a maximum variation of 15 dB, depending on the signal-to-noise ratio phase. Even though many of these studies suggest the importance of binaural considerations, current hearing evaluation methods, with prostheses and without prosthesis, first deal with monaural tests, for example, checking one ear at a time.

Lack of Specialized Sound Considerations.

When audiometric signals are sent as a conversation or noise to the ear via conventional audiometers and associated transducers, the perception of sound by the subject is not localized at any particular point in space (see Specifications of Audiometers, ANSI-S3.6-1989, American Standarda National Institute). For example, in the audiometric evaluation of a conversation, the volume of the stimulus of the conversation is adjusted for one ear, and the volume of the noise stimulus is adjusted in the opposite ear separately. The test subject perceives sounds inside the head and its location is limited in the left and right directions. This type of signal presentation and perception is intercranial and is different from what humans usually perceive. Recent studies conducted by Bronkhorst and plomp, and Begault, refer to studies of the advantages of previous binaural interaction, using the techniques of localization of audifinos (see Bronkhorst, AW, Plomp, R., The effects of Head-lnded Interaural Time and Level Differences on Speech Intelligibility in Noise, Journal of the Acoustical Society of America, vol 83, No. 4, 1988, pp. 1508-1516, Bronkhorst, AW, Plomp, R., The Effects of Multiple Speech-like Maskers on Binaural Speech Recognition in Normal and Impaired Hearing, Journal of the Acoustical Society of America, Vol.92, No. 6, 1992, pp. 3132-3139, and Bagault, DR, Cali Sign Intelligibility Improvement Using a Spatial Auditory display, Ames Research Center, NASA, Technical Memo 104014, April 1993). The results of these studies conclude that the perception of conversations depends not only on the intensity of volumes or levels, but also on the spatial relationship between sound and noise. 3. Lack of Evaluation Methods in Realistic Hearing Environments.

The intelligibility and discrimination deteriorate with the presence of conversations that share other environmental sounds. Additionally, the acoustic props of a room, for example, walls and objects within the room, play an important role in the filtering process of the source of the original signal. These filtering effects are especially significant for hearing impaired individuals who usually have a limited frequency response and dynamic range in their auditory function.

Current methods that present environmental sounds and by means of conventional transducers do not represent the acoustic reality of the typical auditory condition. The sound material recorded via recorders, compact discs or digital computer tape is subject to the filtering effects of the transducers used and / or the acoustics of the clinical installation room. There are no auditory evaluation methods that can evaluate or predict the auditory behavior of an individual in a specific and realistic scenario.

For example, the auditory behavior of a child with hearing impairment in a typical classroom, and the auditory functioning of the child with a specific hearing aid, for example, hearing aids in the same classroom. This and other auditory experiences are considered facts of life that can not be treated in a clinical setting (see Mueller, H.G. Hawkins, D.B. Northern, J.L. Probe Microphone Measurements: Hearing Aid Selection and Assessment, 1992, pp. 69), lll. Limitations of current methods and equipment to measure real-ear (REM).

In recent years, real hearing measurement (REM) systems were developed to evaluate the on-site performance of an auditory prosthesis. The REM system consists of a test of the response of the ear to free field stimuli, for example, loudspeakers, taken from the membrane of the eardrum. A secondary reference microphone is placed outside the ear canal near the exit opening of the ear canal. The reference microphone is used to calibrate the test probe and to regulate the level of the stimulus as the head moves relative to the free field speaker.

For a complete REM evaluation, the actual auditory response without prosthesis, for example, auditory canal, is measured first. Subsequently, the characteristics of the auditory prosthesis are calculated based on the natural response characteristics of the auditory canal and other criteria (see Mueller, HG, Hawkins, DB Northern, JL Probé Microphone Measurements: Hearing Aid Selection and Assessments, 1992 Ch. 5) When a hearing aid is prescribed, ordered and received on a subsequent visit, the prosthesis is inserted over the probe and adjusted to match the characteristics of the prescribed prosthesis.

The REM evaluation and REM-based prescription methods provide considerable improvements over the previous adjustment methods which fell into the combination of audiometric data and 2-cc fit specifications of hearing aids. Although REM offers in situ operation of the hearing aid, it suffers from a large number of fundamental problems, as described below: 1. The test results vary considerably depending on the position / orientation of the speaker to the ear, particularly at high frequencies (see Mueller, HG Hawkins, DB Northern., JL Probé Microphone Measurements: Hearing Aid Selection and Assessment, 1992, pp. 72 -74). 2. The measurements of the real oñido are taken with a specific type of stimulus, orientation and distance of auditory source, and acoustic of the room. The specific conditions of the test may not represent realistic acoustic scenarios such as those faced by prosthetic users. In fact, when using the conventional REM system, an auditory prosthesis can be optimized for a specific condition by concentrating the optimal functioning under other circumstances that may be more important for the individual who uses the hearing aid. 3. An accurate REM system requires carefully placing the test probe into an individual's ear canal. The closer the probe is to the eardrum, the more accurate the results will be, particularly when measuring high frequencies (see Mueller, HG Hawkins, DB Northern., JL Probé Microphone Measurements: Hearing Aid Selection and Assessment, 1992, pp. 74 -79).

Current methods of probe placement are highly dependent on the skill of the operator and the specific length of the channel, which is about 25 mm in average adults. Current REM methods rely on visual observation of the probe. This is especially problematic when a hearing aid is placed in the canal during the prosthesis evaluation process. The only exception to the conventional visual method is found in the acoustic response method developed by Nicolet Corp. For use in the Aurora system (see Chan, J., Geisler, C, Estimation of Eardrum Acoustic Pressure and Ear channel Lenght from Remote Pointers in the channel, J. Acoust, Soc. Am. 87 (3), March 1990, pp. 1237-1247, and US Patent No. 4,809,708, Method and Apparatus for Measuring the Real Ear, March 1989). However, the Nicolet acoustic response method requires two calibration measurements to place the probe in the desired position within the ear canal. 4. The results of REM tests depend considerably on the placement of the eference microphone near the ear. Errors are especially significant at frequencies of 6 KHZ and higher (see Mueller, H.G., Hawkins, D.B., Northern, J.L. Probe Microphone Measurements: Hearing Aid selection and Assessment, 1992, pp. 72-74).

. REM instruments use field sound speakers in a room with ambient noise that often exceeds 50 dB SPL of the standard audiometric frequencies. Therefore, stimulus volumes of 60 dB or more are needed to produce measurements that have sufficient noise signals. This is problematic if low volume acoustic stimuli are required for the characterization of auditory prosthesis performance.

IV. The problem of the correlation between diagnosis, prescribed formula, and real measurements of the ear.

A significant factor that contributes to the results of a hearing prosthesis adjustment is the problem of properly correlating the diagnosed data with the adjustment needs of the individual with hearing impairment. Diagnostic measurements are usually taken in db HL with transducers that are calibrated in 6-cc actuators. The auditory prosthesis specification and performance evaluation employ 2-cc couplers, which do not represent the real ear. The adjustment involves the use of one or more prescriptive formulas, with results that vary as much as 15 dB from the same diagnostic data obtained from standard audiometric frequencies, see Mueller, H.G., Hawkins, D.B., Northern, J.L. I tested Microphone Measurements: Hearing Aid selection and Assessment, 1992, pp. 72-74). These adjustment formulas incorporate conversion factors with static bases that simplify the correlation of the auditory prosthesis requirements for a particular auditory problem. However, it is known that the averaged conversion factors vary considerably with respect to the individual conversion factors measured objectively.

A large number of methods and protocols have been suggested to remedy the errors associated with faults in the evaluation and correlation of data (see Sandberg, R., McSpaden, J., Alien, D., Real Measurement from Real Ear Equipment. Hearing Instruments, Vol. 42 No. 3, 1991, pp. 17-18 Measurement (REM) However, many of these protocols have not been widely accepted due to the limitations of conventional audiometry (REM) equipment and other factors related to the efficiency of the protocols proposed in clinical facilities.

Auditory rehabilitation through the use of hearing aids remains the only viable option for many individuals with hearing impairments who can not be treated medically or otherwise. A complete audiometric evaluation is required before placing a hearing aid. Pure tones and one or more word perception tests are usually included in the basic audiometric test battery. It is also possible to take measurements of the maximum threshold to establish a profile of the auditory dynamic range, in addition to the frequency response profile obtained in the auditory threshold audiogram test. After the audiometric evaluation, a hearing aid is prescribed, selected, ordered and subsequently tested and adjusted after receiving it from the manufacturer or assembled in the clinic. The adjustment or determination of the electroacoustic parameters of a typical hearing aid, involves a combination of measurements objective to achieve the desired characteristics based on one or more prescriptive formulas and subjective measures based on the subjective response of individuals to a conversation and other sounds at different volumes.

Conventional audiometric methods, which use head headphones, inserts, or field headphones, rely on the presentation of acoustic energy to the individual's ear, so that it is not representative of sounds sent under realistic auditory conditions.

Another major disadvantage of conventional audiometric methods is the inability of such methods to accurately and objectively evaluate, in absolute physical terms such as dB SPL, the auditory function of an individual with respect to the interior of the inner ear to correlate the results of the evaluation without prosthesis with the requirements of the hearing prosthesis. An exception is the "mike" probe calibration adjustment system developed by Ensoniq, which only refers to accuracy in the test (see Gauthier, EA, Rapisadri, DA A Threshold is a Threshold is a Threshold ... or is it Hearing Instruments, vol.43, No. 3, 1992).

Additionally, audiometric methods and instruments are not capable of simulating the electroacoustic functioning of one or more conventional and auditory prostheses and of evaluating the simulated function in real acoustic conditions relevant to the unique hearing requirements of individuals. The master hearing prosthesis concept, which gained some popularity in the 70's and 80's, involves an instrument that presents simulated hearing aids to the hearing aid user (see Selection Instrumentation / Master Hearing Aids in Review, Hearing Instruments, Vol. 39, No 3, 1988) Veroba et al (U.S. Patent No. 4,759,070, Patient controlled Master Hearing Aid, Jul. 19, 1988) discloses a patient-controlled hearing aid module, which is inserted into the ear canal and connected to a patient module. test that is inserted into the auditory channel and connected to a module that offers multiple options to process signals, for example, blocks of analog circuits, to the individual. The characteristics of the auditory prosthesis are determined through a tournament process of elimination, while the person with hearing impairment is presented with sounds of real words, reproduced from tapes via a set of headphones located around the head of the person with disabilities. auditory The process of adjusting the system is based on responses from the auditory impaired subject who can continually decide on an alternative signal processing option, and presumably arriving at an optimal setting.

The process of adjustment via the Veroba system, commercially known as the Programmable Auditory Comparator, an essentially absolute product, does not include any objective measurements or calculations to select and adjust the hearing aid. In fact, the whole adjustment process is based on the subjective response of the person with hearing impairment. Clearly, most individuals with hearing impairment can not explore the spectrum of various complexes and interrelated acoustic parameters of a hearing aid under various auditory environments in an adequate manner and time. A serious limitation of Veroba is that it does not teach how the operation of the prosthesis is related to the response of the disabled individual previously determined during the audiometric evaluation process.

An important claim of the Veroba system is the stimulation of a realistic acoustic environment via recorders and loudspeakers located around the head. However, the recorded acoustic signals that are reproduced are subsequently subject to acoustic modifications due to the characteristics of the hearing aids, the position of loudspeakers with respect to the ear and head, and the acoustic characteristics of the room, for example, wall reflections and acoustic absorption. . A realistic hearing condition can not be achieved with the Veroba system, or any other. Additionally, Veroba is not able to manipulate the acoustic condition of its recorded form, for example, by projecting an audio source in a specific place within the three-dimensional acoustic space with a specific acoustic condition.

Another hearing aid simulator, the ITS hearing aid simulator developed by Brakthrough, Inc. offers computer digital audio playback of recordings obtained from the output of various hearing aids (see ITS- Hearing Aid Simulator, Product brochure, Breakthrouh, Inc., 1993) Each recorded segment represents a specific acoustic input, auditory stage, auditory prosthesis model, electroacoustic auditory prosthesis set. The recorded segments require memory space either on the hard disk or in other known ways to store the memory, such as the compact disk memory reader. This approach based on digital recording makes impractical the arbitrary selection of a hearing aid, and the entry of stimuli for the individual with hearing impairment, when all possible combinations are considered. Additionally, the effects of the sizes of the openings of the hearing aids, and the associated occlusion effect, the depth of insertion, the external ears of the individual, can not be simulated with the proposed hearing aid simulator, because it rests on conventional transducers, for example, hearing aids inserts and hearing aids for the head.

For similar reasons, many of the commercially available master hearing aid systems do not have the ability to accurately simulate a hearing aid in a realistic listening environment. Additionally, these systems do not include objective measurement methods to evaluate a simulated prosthesis versus non-prosthetic conditions. For this and other reasons, prescription and virtual hearing aids are adjusted without using a master hearing aid or hearing aid simulator instruments.

The REM equipment in the state of the art allows to measure the acoustic response within the channel. The acoustic stimuli are typically generated by the REM equipment and delivered via a loudspeaker, normally positioned at 0o azimuth, or with two loudspeakers positioned at 45a of azimuth, with respect to the transverse plane of the head. Response measures, for example, field-free to real-ear transfer function, are essentially one-dimensional, because they only have a simple transfer function for each ear in a particular speaker-ear relationship, and for therefore they are not able to establish a multi-dimensional profile of the real response of the ear. Another disadvantage of conventional equipment and methods REM speaker is the lack of real voice stimuli, primarily due to the fact that most of the REM equipment only offers tone-pure, clear tone-pure, voice noise and other similar voice stimuli. These stimuli do not explore responses to particular voice segments that may be important for the disabled individual during prosthetic and non-prosthetic conditions. Recent developments concerning electroacoustic measurements of hearing aids are related to the hearing prosthesis test in more realistic conditions. Real tone signals of pure tones and word-like sounds were used in a recommended test protocol; Spectrogram parts indicating time, for example, compared acoustic electrical energy analysis in dB SPL versus frequency, when comparing auditory prosthesis input and output (see Jamieson, D., Consumer Based Electroacustic Hearing Aid Measures, JSLPA Suppl. 1, Jan. 1993). The limitations of the proposed protocol include: limited acoustic reality due to the specified sound delivery method, via a loudspeaker to a hearing aid in a closed chamber; limited value of spectrogram indications that do not directly indicate the relationship between audibility and discomfort.

Other recent developments include the presentation of three-dimensional sound via overhead head transducers (see Wightman, F.L.

Kistler, D.J. Headphone Simulation of free-Field Listening. I: Stimulus Synthesis, JASA, vol. 85, no. 2, 1989, pp. 858-867; and Wightman, F.L. Kistler, D.J., Headphone Simulation of free-Field Listening, II Psychophysical Validation, JASA. vol. 85, no. 2, 1989, pp. 858-867; vol. 85, no. 2, 1989, pp. 868-878); These three three-dimensional effects are achieved by recreating the acoustic response within the channel of free-field signals via headphones or loudspeakers (see US Patent No. 4,118, 599, Stereophonic Sound reproduction System, August 26, 1980; 4,219,696 Sound Image Localization Control System, August 26, 198 'US Patent No. 5,173,944, Head Related Transfer Function Pseudo-Stereophony, December 22, 1992; US Patent No. 4,139,728, Signal Processing Circuit, February 13, 1979; and US Patent 4,774,515, Altituded Indicator, Sep. 27 1988). This involves digital filtering of source signals based on head-related transfer function (HRTF). The HRTF function, which is essentially a response without a real-ear prosthesis in three-dimensional space, is a frequency-dependent frequency-dependent delay and frequency measurement that results from head shading, pinna, ear shell and auditory canals. The HRTF function allows the externalization of localized sounds with headphones. The signal sources that are processed with HRFT provide the listener with a free-field listening experience, according to the controls of the signal processing parameters.

The efforts in development and research in three-dimensional audio are mainly focused on commercial music recordings, improvement of recordings and improvement of human-machine interface (see Bagault, DR, Cali Sign Intelligibility Improvement Using a Spatial Auditory display, Ames research Center, NASA Technical Memorandum 104014, April 1993, and Begault, D., Wensel, E., Headphone Localized of Speech, Human Factors, 25 (2), pp. 361-376, 1993) and virtual reality systems (see The Beachtron-Threedimensional audio for PC-campatibles, reference manual, Crystai River Engineering, Inc., Revision D, Nov., 1993). The objective of these three-dimensional audio systems has been limited to simulating situations in a virtual, approximate acoustic environment, because individualized HRFT is not used.

The application of three-dimensional audio in objective measurement of hearing in the auditory canal in conditions with prosthesis, without prosthesis and with simulated prosthesis will be a significant starting point and extremely useful in relation to the known audiometric techniques.

SUMMARY OF THE INVENTION The invention provides an audiometer (VEA), which is a system used in the evaluation of human auditory function with auditory prosthesis, with simulation of prosthesis and without hearing prosthesis. A pair of intra-canal prostheses (ICP) are placed in the two auditory channels of an individual to send acoustic stimuli. A measurement system, partially inserted in the IPC, measures the response conditions within the auditory canal near the eardrum during the auditory evaluation, providing a common reference point to correlate the responses in the assessment conditions without prosthesis, with prosthesis and with simulated prosthesis. It also provides a unique and modular hearing aid that is defined according to the result of the auditory evaluation that includes highly configurable electroacoustic and electronic signal processing elements.

During the evaluation without prosthesis, the system performs audiometric tests, such as pure tone threshold, annoying loud volume levels (UCL), conversation reception threshold, word discrimination. These auditory peripheral tests, as well as other central auditory processes (CAP), evaluate the auditory function of the human in response to acoustic stimuli measured near the eardrum in terms of absolute sound pressure level (SPL), unlike conventional stimuli, which are presented in terms of relative hearing level (HL).

Another significant function of VEA is the ability to synthesize, or create, acoustic signals that are representative of signals received in real-sound environments in a three-dimensional space. This is achieved through the incorporation of various acoustic room filtering effects, atmospheric absorption, expansion loss, atrial septal retention and spectral shape of the external ear and other body effects. For example, an auditory condition in which a teacher who speaks in a classroom, is digitally synthesized and acoustically sent via the ICP to a child to assess their hearing ability with and without prosthesis in a classroom. In addition to the spatial signal of the primary conversation, spatial noise signals from children in class are presented, optionally, to evaluate the discriminating capacity of the child in the presence of environmental noise.

The evaluation method without prosthesis, involves both ears in auditory experiences similar to the sounds heard by humans normally, each ear receiving a part of the acoustic energy according to the relationship between each ear and the different sources of virtual audio. In contrast, conventional audiometric methods present intracranial acoustic stimuli to each of the ears, for example, words to one ear and ambient noise in the opposite ear.

R The simulated prosthesis evaluation of the VEA system is carried out by incorporating an electroacoustic presentation of a desired hearing prosthesis into the digital synthesis of acoustic signals without prosthesis. The electroacoustic parameters of auditory prosthesis stimulation include a microphone, reception and transfer functions, and an amplifier.

Generalized or specific acoustic models are presented digitally at the entrance of the simulated auditory prosthesis process. Specific acoustic models that represent auditory scenarios that are important for the individuals subjected to the evaluation and that can be selected and manipulated by the operator of the clinic, for example, a model with the teacher speaking within a class noise environment model with a specific source-ear relationship. A typical goal in such a scenario is to maximize the intelligibility of words by optimizing the electroacoustic characteristics of the simulated hearing aid. The generalized acoustic conditions represent acoustic scenarios that are associated with normative response data. An example of a generalized model is a list of audiological words, such as W-22, that have a specific noise spatial environment. The results of the evaluation are compared with the general normative data model, stored in the system memory.

The VEA system also stimulates other hearing effects that can not be stimulated by the digital synthesis process due to the unique effects of the individual ear. These effects include the effect of occlusion, size of the aperture and the potential for oscillatory auditory distortion. The occlusion effect is a phenomenon that results from changes in the perceived characteristics of the voice itself when the auditory canal is obstructed with an auditory prosthesis.

Additionally, the VEA system offers a method to measure different acoustic transfer functions in a three-dimensional space, which are incorporated during the different synthesis processes to create virtual acoustic conditions for an individual.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a schematic block diagram showing the major components of the VEA system, including the dual ICP prostheses inserted into the ear canal of an individual; a microphone system; and a computer system, including a digital audio synthesizer module, a module of a digital audiometer, and a virtual acoustic space rating module according to the present invention.

Fig 2 is a schematic block diagram of a digital audio synthesizer module according to the present invention; Fig. 3 is a schematic block diagram of a digital audiometer module, in accordance with the present invention; Fig. 4 is a schematic block diagram of a virtual acoustic space measurement module, according to the present invention; FIG. 5 is a schematic block diagram of a virtual acoustic space measurement system, according to the present invention; Fig. 6 is a perspective view of an adjustable chair used to position the patient's head during the virtual acoustic space test; FIG. 7 is a schematic diagram showing the speech adjustment in a virtual acoustic space measurement system, including transverse flat speakers and sagittal flat speakers, in accordance with the present invention; Fig. 8 is a schematic diagram showing an example of a transfer function transposition at a point 3 of the transfer functions measured at the points nt \ and mi in transverse planes of two dimensions, according to the present invention; Fig. 9 is a schematic diagram showing an example of an embodiment of a real auditory scenario for auditory evaluation conditions without prosthesis, and in particular shows a master-emitter / child-receiver scenario including direct acoustic trajectories PR1 and PL1 and early reflection trajectories PR2 and PL2 for the right and left ears of a child-recipient, according to the invention.

Fig. 10 is a schematic block diagram showing an embodiment of a real acoustic scenario for hearing evaluation conditions without prosthesis, and in particular shows a master-emitter / child-receiver scenario, during an evaluation without prosthesis , according to the present invention.

Fig 11 is a partially sectioned perspective view showing an intra-canal prosthesis (ICP) for an ICP-ITE representing the placement of hearing aids for ears in the superficial ear canal, in accordance with the present invention: FIG. 12 is a partially sectioned perspective view showing an intra-canal prosthesis (ICP) for an ICP-ITC representing auditory prostheses for placement in the channel according to the invention; FIG. 13 is a perspective view showing one end of the intra-canal prosthesis plate (ICP), including probes that attach to the plate and probe placement according to the invention; Fig. 14 is a side view, partially sectioned showing the central ICP module for a two-part ICP configuration, according to the present invention.

Fig. 15 is a side view, partially sectioned showing inserts with adjustable outlet openings and an ICP-ITE sleeve for an ICP-ITE configuration, according to the present invention.

FIG. 16 is a side view, partially sectioned, showing an ICP-ITC sleeve for a two-part ICP configuration, in accordance with the present invention; Fig. 17 is a side view, partially sectioned showing ICP-ITC in two parts, according to the present invention; Fig. 18 is a partially sectioned side view, showing an ICP with programmable output opening, according to the present invention.

Fig. 19 is a side view, partially sectioned showing an auditory prosthesis and direct acoustic coupling method, including direct acoustic coupling via a magnetic attraction method, in accordance with the present invention; Fig. 20 is a side view, partially sectioned showing an auditory prosthesis and a method of direct acoustic coupling to an ICP, including direct coupling via a direct coupling method, according to the invention, Fig. 21 is a side view, partially sectioned showing an auditory prosthesis and a direct acoustic coupling method to an ICP, including a programming and acoustic coupling interface, according to the present invention.

Fig. 22 is a side view, partially sectioned showing an auditory prosthesis and acoustic coupling to an ICP via an acoustic coupler, according to the present invention; Fig. 23 is a schematic block diagram showing an example of an adjustment process, providing the virtual electro-acoustic audiometer system according to the present invention.

Fig 24 shows a graph generated by the computer, showing a module of reference measurements, according to the present invention.

Fig. 25 shows a graph generated by the computer showing an evaluation module without prosthesis, according to the present invention; Fig. 26 shows a graph generated on the computer showing a predetermined prosthesis module, according to the present invention; Fig. 27 shows a graph generated in the computer showing an evaluation module for simulated prosthesis, according to the present invention; Fig. 28 shows a graph generated in the computer showing a prosthesis evaluation module, according to the present invention; Fig. 29 is a linear graphical representation of SPL measurement variations against the distance of the probe from the membrane of the .9. tympanum for tones 5 KHZ and 15 KHZ for an individual, according to the invention.

The. Fig. 30 is a graphical representation of pressure of the SPL measured for 5 KHZ and 15KHZ during the advance of the probe to 6 mm of the tympanic membrane, according to the invention, FIG. 31 is a graphical representation showing the pressure of the SPL measured for 5 KHZ and 15 KHZ during the advance of the probe to 5 mm from the eardrum, according to the invention; Fig. 32 is a graphical representation showing the SPL pressure measured for 5 KHZ and 15 KHZ during the advance of the probe to 4 mm of the eardrum, according to the invention; Fig. 33 is a schematic block diagram showing an example of a teacher-emitter / child-receiver scenario, using a predicted prosthesis evaluation for the right ear, in accordance with the present invention; Fig. 34 is a schematic block diagram showing an example of a teacher-emitter / child-receiver scenario, using a simulated prosthesis evaluation for the right ear, according to the present invention; Fig. 35 is a schematic block diagram showing a simulated hearing aid with directional microphone, in accordance with the present invention; Fig. 36 is a schematic block diagram showing an example of the realization of realistic acoustic scenarios for auditory evaluation conditions with prostheses, according to the present invention; Y Fig. 37 is a schematic block diagram showing an example of the projected and simulated oscillatory auditory distortion of a simulated hearing aid.

DETAILED DESCRIPTION OF THE INVENTION The following definitions should apply to the present description: Window: Refers to a graphic area displayed on the screen of a computer, which represents a set of controls, objects, fields 9 c; of inputs and diagrams, which are grouped in a logical functional form.

Iconized: Refers to an active window that is displayed as a Cone Its operation is disabled, but can be activated by "clicking" on the icon shown on the computer screen. The virtual electroacoustic audiometer (VEA) described here is a unitary instrument that is used in the auditory evaluation with prosthesis, without prosthesis and with simulated prosthesis. VEA offers new methods for adjusting and analyzing hearing aids, using a combination of digital synthesis of realistic acoustic stimuli and response measures within the channel through adjustment and evaluation processes.

Fig. 1 shows the main components of the 15 VEA system prototype. A pair of intra-canal prosthesis (ICP) 22 is inserted into the ear canal 21 of an individual to send acoustic stimuli 25 in a manner similar to those of the hearing aid. Each ICP contains a receiver, for example, a loudspeaker, to transmit acoustic signals to the membrane of the eardrum26. The ICP also contains a probe 24 for measuring the acoustic response that results from the unique interaction of the reception of the acoustic stimulus and the characteristics of the ear canal of an individual. A microphone system consisting of a probe 24 and a microphone probe 23 measures the acoustic signals of the auditory channel 21 and sends electrical signals representative of the acoustic signals. A response board 27 is provided to record a response of the test 20 during several evaluations. auditory Each ICP receiver 22 is electrically connected to the digital audiometer module 19 which provides an interface of several audiometric transducers including the ICP receiver 22 and the probe measurement system.

The module of the digital audiometer is connected to the module 18 of the audio synthesizer and to a module 14 for measuring the virtual acoustic space via several intermodular cables.

The module for measuring the virtual acoustic space includes an output terminal 16 for connecting to a plurality of test speakers. These modules can be contained within a personal computer. 11, which also contains the common accessories of the computer, such as devices for storing memory 17, a monitor 10, a board 12 and a "mouse" 13. The devices for storing memory will be called hereafter as system memory 17. 9? In figures 2, 3, and 4, block diagrams of the digital audio synthesizer, digital audiometer and modules for measuring the virtual acoustic space are shown. In the prototype of the invention, the digital audio synthesizer, the digital audiometer and the modules for measuring the virtual acoustic space are connected to the personal computer by means of the Industry Standard Architecture (ISA) 34 interface and the ISA 39 interface of the computer (See figure 2 as an example). The digital data representing the audio sources are scrambled from the system memory via the interface 24, and are digitally processed by a digital signal processor 33 within the digital audio synchromesh module 18. The digitally processed data is subsequently converted to an analogous form using a digital-analog converter 35 which normally operates at a conversion rate of 44.1. KHZ, or another percentage depending on the signal bandwidth required.

The digital audio synthesizer module also receives analog signals that represent audio signals via the 3.1 input connector coming from external audio sources such as recorders or CD (not shown), the analog signals received are converted to digital signals by the analog-digital converter 32, for signal processing via the digital signal processor 33.

Multiple digital audio synthesizer modules can be used to achieve the system's ability to process digital signals.

This is particularly useful for the synthesis of binaural signals in real time. A large number of digital audio synthesizer modules are connected in cascade by connecting the output 38 of an -o digital audio synthesizer module to an auxiliary input 30, or input 31 of another digital audio synthesizer module. The internal and auxiliary signals are combined within the module in a collector node 36, before the output. In the prototype of the audition, two digital audio synthesizer modules are used. Each module employs a signal processor such as Motorola DSP 5601 digital set at 40 MHZ, the analog output 38, of the digital audio synthesizer module 18 is sent to the mixer 45 of the digital audiometer module 19 (FIG. 3) via a connector 42, the Analog audio signals received in the digital audiometer module are mixed by means of a mixer circuit 45, amplified via an audio amplifier circuit 46 and the impedance is matched and enrouted to several audiometric transducers via an audiometric transducer interface circuit 49. The outputs of the audiometric transducers include ICP s 50 vibrating bones 51 (not shown) a hearing aid 52 (not shown) and other conventional methods for sending sounds to an individual's ear.

The signals amplified from the audio amplifier 46 are also sent to the input 31 of the digital audio synthesizer module from an output connection of the audio amplifier circuit 47. The mixer circuit 45 also includes connections for receiving audio signals from ICP55 microphones, a microphone of the attending physician 56 (not shown), and a patient microphone 57 (not shown), and a microphone amplifier 58.

The external line signals received in the input connectors 53 are also amplified via an amplifier 54 and sent to the mixer circuit 45. A response board interface circuit (KEYPAD) 60 is used to convert the system to the response of the board (KEYPAD) via a connector 59, to record the response of the individual to an acoustic stimulus during the various audiometric evaluation processes. The operator's microphone connected to the digital audiometer module allows the doctor to communicate with the patient through the ICP. The patient's microphone allows the patient to communicate with the doctor during certain audiometric tests that require verbal responses from the patient. The patient's microphone is also used to measure the occlusion effect, as described in more detail below.

N The digital audiometer module also includes a PC 43 busbar connection and an interface circuit 44 that connect the digital audiometer module with the VEA to coordinate the operation of the module at the system level. The VEA also includes a system to measure the virtual acoustic space (Figure 5) that is used to evaluate the acoustic transfer function of an individual. In Figure 4, a block diagram of the module for measuring the virtual acoustic space 14 is shown. The module for measuring the virtual space receives electrical signals, representing different acoustic signals, from the output connector of the digital audio synthesizer module 38 via a set of input connectors 54. The adjustment of the input signal level is completed via the mixer circuit 65, an audio amplifier circuit 66, and an interface circuit 71. The output of the module for measuring the virtual acoustic space is coupled to several loudspeakers 16. The module for measuring the virtual acoustic space also includes a PC 68 bar connector and a PC 57 interface circuit that connect the module to measure the virtual acoustic space with the VEA to coordinate the operation of the model at the system level. Said coordination includes processing information indicative of the position of the patient's head connected to the module from a sensor of the position of the patient's head via a connector 70 and a position sensor interface circuit 69.

An adjustable chair 68 is preferably used to ensure a proper position of the ear within the space being measured, as shown in Figure 6. A vertical leveler 79 adjusts the vertical position of the individual on the chair. A back adjuster 81 adjusts the support of the backrest chair 80. The head support 82 is adjusted to support the head of the individual sitting on the chair. A reference arm of the ear position 84 provides a reference target by pointing out the output openings of the ear canal 83. The reference arm of the ear position 84 is preferably removed from the ear area to minimize acoustic reflection inside. of the ear area during the measurement of the transfer function.

An infrared reading method (not shown) can be used to position and maintain the head in the proper position with respect to loudspeakers 16 (Figure 5; 89-94, fig.7). A light-reflecting object (not shown) is placed just below the ovule of an individual's ear, to reflect the infrared light from the light emitter. A suitable placement of the ear is indicated by the reflected light, which is detected by the interface of the position sensor 69 (Figure 4).

The system for measuring the virtual acoustic space generates several transfer functions that are used during the auditory evaluation process. Generally, the transfer function of a linear system Or define a complex function H (jw) that has magnitude and phase characteristics that are frequency dependent (w). Once the transfer function is determined, the response of the system to an arbitrary input signal can be predicted or synthesized.

The transfer function in the system to measure the virtual acoustic space is obtained from a set of acoustic sources, such as the loudspeaker, placed in a three-dimensional space. The loudspeaker is composed of six 89-94 loudspeakers placed at an equal distance (from the reference of the patient's head 88), as shown in figure 5 and 7) the reference point of the head 88 is defined as the point where the line connecting the centers of the channel exit openings meet 21 auditory.

Four of the speakers for example 89, 90, 91 and 92 are placed in the transverse plane 95 that contain the point of the head 88. The four speakers are placed at the azimuth angles at 0o, 45o, 315o and 260o. respectively as shown in Figure 7. Three of the speakers for example (89, 93, and 94), are placed in the sagittal plane 96 that contains the reference point of the head 88. The loudspeakers 89, 93, and 94 they are placed at the following altitude angles 0o, 45o and - 45o respectively as shown in figure 7.

A9 A set of transfer functions for the configuration of the six speakers shown in Figure 7 allow six pairs, for example: measurements of the left and right ear, frontal measurements where the head is in front of the speaker 89. Six additional pairs of measurements backs are preferably taken when the head is on the side opposite the speaker. According to the above, a set of complete transfer function consists of 12 pairs of measurements representing finite points is a sphere of a radius (d), Of the 12 pairs of measurements, eight pairs are in a transverse plane and six pairs they are placed in the sagittal planp. Two pairs are common to both planes. The pairs contain, not only, individual transfer functions for each ear, but also the interatrial phase relation with respect to each speaker. The training to measure the transfer function with a pair of probes placed near the ear membrane in the unobstructed ear canal will be referred to hereafter as the non-prosthetic transfer function Hua (PNjw), where pn is the place of the speaker n defined by podalways d, .c,? , where d is the distance between the speaker and the reference point of the head as shown in Fig. 7 in A.; ? is the azimuth angle of the sound incidence with respect to the transverse plane as shown in Fig. 7 in A; and you place the angle of altitude with respect to the sagittal plane, as shown in Fig. 7 in B. Hua (Pn, jw) represents the acoustic transfer function that results from the propagation of the sound of the speaker #na membrane of the eardrum when considering various acoustic factors, including loss by atmospheric propagation, effects of the head, torso, neck, pinna, ear shell, ear canal, eardrum membrane, and middle ear impedance. Transfer measurements can also be made with a probe placed on the surface of the ICP plate. In the following, reference will be made to said measurements with Hfp (Pn, jw), which represents the speaker transfer function #na the plate surface (fp) of the ICP (discussed in more detail below), in a representative place of the position of the microphone on the surface of the plate of a simulated hearing aid. Generally a transfer function H (p (d.cc,?), Jw) at an arbitrary point Pd.oc,?, In the space at the coordinates d,?, Oc, can be interpolated from the set of transfer functions measured as shown in Fig. 8. For example, it is known that the sound pressure of an audio source is inversely proportional to the distance under normal atmospheric conditions. Additionally, a transfer function of a point in space can be approximated by the percentage of the two closest measured transfer functions. Fig. 8 shows an example of an approximate transfer function H (i3, jw) interpolated in the transverse plane at point 3 of the transfer functions H (i1, jw) and H (i2, jw), which they are also interpolated from the transfer functions H (m1, jw) and H (m2, jw) measured with speakers # 1 (89) and # 2 (90).

Thus, H (3, jw) = H (m1, jw) + H (m2, jw) / (2 * Lat Q, w) Where Lat (jw) is the atmospheric loss transfer function due to atmospheric absorption and sound scattering.

Similarly, interpolation can be used to approximate any transfer function at an arbitrary point in a three-dimensional space from the percentage of the closest measured transfer functions. The accuracy of the interpolated functions can be improved by taking additional measures of additional speakers and / or head orientations with respect to the hearing aids. The prototype of the invention employs a practical composition between the number of loudspeakers, for example six in the prototype of the present invention, and two individual orientations, for example, an orientation to the front and a back. Furthermore, no interpolation of non-linear transfer function can be more appropriate if it is determined from the statistical data obtained from transfer function measurements of a large number of individuals. 4fi Other measures of transfer functions by the VEA system include two points: (1) the Hicp-rec (jw) transfer function, which represents the ICP receiver for the electroacoustic transfer function within the channel, which is measured by a probe when the ICP is placed inside the auditory canal of the individual; 2) The HICP-mic transfer function (jw), which represents the electroacoustic transfer function of an ICP speaker to the hearing aid microphone during the assessment of the hearing aid; and 3) The HICP-fv transfer function (jw), which represents the acoustic leak, for example, the acoustic auditory distortion of the ICP receiver measured on the surface of the ICP board. The transfer functions that are HUA (PN, JW), HFP (PNJW), HICP.REC (JW), HICP-mic Qw) and HICP, fb (jw) are used in various combinations to digitally synthesize acoustic signals, representing auditory conditions, without prosthesis, with simulated prosthesis or prosthesis, with the realism that is not possible with the conventional methods of evaluation and adjustment.

In figure 9, for example, an acoustic environment is created with a teacher-emitter 101 and a child-receiver 102 in the following manner: With direct acoustic trajectories PR1 and PL1, and reflection paths PR2 and PL2 for the left and right ears of the child 102. These trajectories are represented by interpolated transfer functions of the child transfer functions 102, previously measured. The acoustic embodiment of the environment of Figure 9 is shown in Figure 10, in which the digital audio register 107 representing the speech of the teacher is taken from the memory of the system 106 and processed digitally by the digital signal processor 114. The digital signal processor carries out the signal processing Hua (PR1, jw) 108, Hua (PL1, jw) 110, Hua (PR2, jw109 and Hua PL2, jw) 111, which represent the trajectories PR1, PL1, PL2 , respectively. The path processes of the left and right ear are added at nodes 112 and 113 and subsequently processed with the inverse transfer functions, 1 / ICP-rec-RT (jw116 and 1 / Hicp-rec-Lt (jW) ( 104) for the left and right receivers of ICP 119/120 respectively.

The reverse transfer functions are performed to cancel the acoustic transfer function that occurs between the ICP receiver and the residual volume of the ear canal, as the sound is sent. The processed right and left digital signals are converted to analog signals by means of the digital-to-analog converter 115 and conducted to the left and right ICPs via the audiometric interface circuit 117. To the process of projecting a virtual audio image to a The receptor in a particular space in a three-dimensional space, as in the case of the teacher-emitter-child-receiver, is called spatialization.

Aa Alternately, live voice signals can be used by the attending physician via the operator's microphone, instead of digital audio data, for spatialization and sending to the receiver using the ICP pair. The volume and virtual position of the spatialized audio source are under control of the virtual audiometer system of the present invention, as explained in more detail below. The transfer function measurements of linear systems that do not vary in time, such as Hua functions (pnjw), Hfp (pnjw), Hicp-rec (jw), Hicp-mic (jw) and Hicp-fb (jW), typically employ separate or pure tone acoustic stimuli. Other stimuli include conversation noise, white noise, and other conversation-like sound signals. The semi-random sound sequence and other signals have been used to reduce the time traveled to compute the transfer function. The computational methods include: Fast Fourier Transformation (FFT), Maximum Length Sequence (MSL), and Time-delay Spectrometry (TDS) (see Rife D., Vanderkooy, J., Transfer-Function Measurement with Maximum-Length Sequences, J., Audio Engineering Soc., Vol.37, No. 6, June 1989, pp. 418-442). The advantages of the MCL and TDS measurements include the reduction of the reflection effects of the room on the transfer function. Another important component of the measurement of the transfer function that is used in the present invention is the direct path transfer function.

AQ In the prototype of the invention the probes of the VEA microphones are calibrated at the reference point of the head when the VEA is installed for the first time. In the clinical facilities these calibration data, stored in the system memory, are subsequently used during the measurement of the transfer function to correct the unique frequency response characteristics of each of the microphones and the unique acoustic characteristic of the fourth.

Fig. 11 is a perspective view, partially sectioned, showing an intra-canal prosthesis (ICP) for an ICP-ITE representing auditory prostheses for placement on the surface of the auditory canal; Fig. 12 is a perspective, partially sectioned view showing an ICP for an ICP-ITC representing auditory prosthesis for placement deep within the ear canal; FIG. 13 is a perspective view, showing one end of the ICP surface plate, including probe tube holders on the surface of the plate and placement of the probe; Fig. 14 is a side view, partially sectioned, showing the central module ICP for a two-part configuration of the ICP; Fig. 15 is a side view, partially sectioned showing inserts with adjustable outlet openings for an ICP-ITE; Fig. 16 is a side view, partially sectioned showing a sleeve for a two part ICP configuration; Fig. 17 is a side view, partially sectioned showing a complete assembly of an ICP-ITC in two parts. Fig. 18 is a side view, partially sectioned showing an ICP with a programmable exit orifice; Fig. 19 is a side view, partially sectioned showing an auditory prosthesis and a method for direct acoustic coupling to an ICP, including direct acoustic coupling via magnetic attraction method fig. 20 is a partially sectioned side view showing an auditory prosthesis and a method for direct acoustic coupling to an ICP, including direct acoustic coupling via an acoustic coupler method; Figure 21 is a side view, partially sectioned showing an auditory prosthesis and a method for direct acoustic coupling, including an interface for programmable acoustic coupling. Fig. 22 is a side view, partially sectioned, showing an auditory apparatus and its acoustic coupling to an ICP, according to the present invention.

In the subsequent figures, those elements of the invention which are common to several prototypes have a common numerical indicator, for example, the ICP of Figures 11 and 12 have a receiver 136, while the container 129 of the prototype of Fig. 11 is different from the prototype container 152 of Figure 2.

The intra-canal prosthesis (ICP) shown in FIGS. 11-22, consists primarily of a receiver 136, a receiver port 149, a probe 133 inserted in the channel 134 inserts 128 inserted into the outlet channel 130 a microphone probe 131 a surface plate 122, and a container made of flexible material, like acrylic. The ICP is designed to represent physical electro-acoustic characteristics of a desired type of hearing aid, with the exception of the generation and processing of the signal that is carried out by the audio synthesizer board of the computerized virtual electroacoustic audiometer system. Figures 11 and 12 show ITE and ITC ICP representing auditory prostheses that are placed on the surface and depth of the canal, respectively. The receiver 136 used in the prototype of the present invention (manufactured by Knowles Corp. of Itasca, Illinois) was chosen for its acoustic characteristics, which are similar to the receivers used in commercially available hearing aids, as well as for its characteristics of very Little noise at the exit. The variations of the ISP receiver of the simulated hearing prosthesis receivers are stored in the VEA system memory as a transfer correction function, used during several simulation processes. The probe 133, preferably made of silicone material and with a diameter of about 1 ml, is inserted into the channel 139 of the ICP as shown in FIGS. 11-22.

An output channel 130 is provided for pressure equalization in the ICP-ITC versions having inserts deep within the channel (figures 12 and 17), and for accommodating the inserts for the ICP-ITE version having insertion in the superficial canal (Figures 11 and 15). In the ICP-ITE versions, an open channel allows the insertion of several inserts into the channel to achieve the acoustic characteristics desired in the place. For example, an insert of a relatively long diameter can be used to reduce the occlusion effect resulting from the increase in the perceived volume of the individual's own voice. On the other hand, an insert with the smaller exit opening can be used to eliminate the acoustic leak of the receiver via the insert. A miniature connector 138 and a connector plug 123 electrically connect the ICP to the VEA system by means of the connector cable 125. The VEA system, in conjunction with the probe system with microphone, allows to measure the effects of occlusion versus types of output aperture and ICPs , as explained later. The ICP also contains two probe holders 124 and a positioning handle 126 for positioning the probe, as shown in FIGS. 11, 12, and 17. FIG. 13 shows in more detail the illustration of the surface plate 122 including the tube holders of the surface plate 124. In the fig, an ICP / ITS sleeve 156 and an ear prosthesis microphone position 132 are also shown. This configuration is used when measuring the acoustic leakage and transfer functions of the surface plate.

F, 9, The ICP container (129, fig.11; 152 fig.11 is preferably made of a flexible material to provide an acoustic and comfortable seal.) A variety of ICP versions can be accumulated to a variety of channel sizes For example, a smaller container is more suitable for pediatric function, while a larger container is suitable for adults who have large canals.The ICP, shown in Figures 11 and 12 is preferably disposable to avoid contamination caused by individuals who have infected ear canals.

An alternative prototype to the invention provides a configuration of two parts of the ICP as shown in FIGS. 14 to 17. A central part 169 (Fig. 14) is inserted into a variety of disposable sleeves 177 as shown in Figs. 15 and 16. This option provides an economical alternative to the configuration shown in FIGS. 11-13 because only the sleeve component is disposable. The central part 179 is encapsulated in a protective material, preferably having semi-flexible properties. A capacitor 167 can be used to filter out extraneous electromagnetic signals that cause audible noise.

The sleeve portion shown in FIGS. 15 and 16 is typically made of flexible material, such as a soft acrylic so that the ICP fits comfortably in a variety of ear sizes and shapes. Fig. 16 shows a suitable sleeve for inserts in the deep channel that represent types of hearing prosthesis ITC and CIC. It is also shown in fig. 16 an acoustic baffle system 186 that provides an acoustic seal while the ICP is inserted into the ear canal.

Fig. 15 shows an ICP sleeve for superficial insertions in the canal representing types of ITE hearing aids. The central part of the ICP is inserted into the sleeve cavity 179 of any ICP, including those shown in FIGS. 15 and 16. The specific size of the ICP sleeve selected by the attending physician depends on the test performed, the size of the individual's channel, and the requirements of the hearing aid simulation. In fig. 17 shows an example of the combined parts of a central ICP and an ICP manga representing an ICP esamble, ITC.

Fig. 18 shows a variation of the output opening mechanism where the size of the aperture is electronically controlled and adjusted (see Zdeblick, K., A Revolutionary Actuator For Microstructures, Sensors Magazine, eb., 1993). This is completed by using a programmable microbalance 193 (such as the NO-300 manufactured by Redwood Microsystems of Redwood City, California) which contains a silicone diaphragm 194 to regulate the size of the exit opening that joins the channel of the .C opening output 197 via the micro-valve port 195. The normal size of the output aperture ranges from a range of .032 and 1.5mm, according to the voltage level supplied from the virtual electroacoustic auread module in response to the operator's test selections. The ICP is also used in a novel way to test a new type of hearing aids adapted to the ICP interface, as shown in fig. 19-22. Unlike the conventional hearing aids and auditory evaluation methods that typically employ remotely placed speakers to send acoustic signals to the hearing aid microphone, the ICP of the present invention presents direct acoustic signals to the hearing instrument microphone 211. 214. The acoustic coupling of the present invention has minimum distance intervals of less than 15mm.

Figs. 19 and 21 show a prototype of the invention wherein the acoustic coupling is carried out by a magnetic attraction method. In said method, the ICP receiver 136 is coupled to the hearing aid microphone 211 by the magnetic attraction between the magnetic disk 206 on the final receiver of the ICP and another magnetic disk 209 near the microphone port of the hearing aid 210, which it is part of the surface plate 218 of the hearing aid 214, as shown in FIG. 19. A sealing ring 205 provides an acoustic seal to minimize leakage in the coupling. It also provides a ? pen of the battery of the hearing aid 221, a control of the hearing aid 219 a circuit of the hearing aid 212, and a channel with exit opening of the hearing aid 217, which represents the conventional components of an apparatus of hearing prosthesis.

Additionally, the prototype of the invention shown in FIG. 21 provides a programmable auditory prosthesis circuit 253 that allows dynamic testing and ITE, via control signals sent by the VEA on a cable 257. FIG. 21 shows an electrically programmable hearing aid with a programmable cable 257 that connects the hearing prosthesis circuit to the VEA of the present invention. These hearing aids contain circuits that are programmable or adjustable by electrical signals. The programming interface shown on the surface plate is adapted to program the route of electrical signals to the auditory prosthesis circuit. The programming interface on the surface plate is carried out via the battery container, which is adapted to conduct electrical signals to the hearing prosthesis circuit. The programming signals and the interface methods are unique for the model of auditory prosthesis chosen by the specification of the auditory prosthesis circuit used. The programming signals and interface methods are known to those skilled in the art, dedicated to the design of prostheses. Other programmable hearing aids that are commercially available use ultrasonic or infrared signals with the appropriate signal interface circuits within the hearing aid.

A method of auditory acoustic coupling couples the ICP receiver 132 to the microphone of the hearing aid 211 via an acoustic coupler 243 as shown in FIG. 20. The extended microphone port 242, unique in the present invention, also acts as a handle to facilitate the insertion and removal of the hearing aid 214 during normal use.

Another prototype of the present invention, shown in FIG. 22, employs an acoustic coupler 290 adapted for insertion into the microphone port 299 of the hearing aid 214. The microphone port has a recess to accommodate an acoustic coupler 291.

Another method of acoustic coupling (not shown) employs a suction ring to couple the ICP receiver to conventional hearing aids that are not equipped with special interface parts.

An important advantage of the direct acoustic coupling of the present invention is to improve the percentage of signal with respect to noise in the microphone of the hearing aid, while the prosthesis is being evaluated or adjusted. This is basically completed by the acoustic isolation of the hearing aid microphone from the environmental noise of the fourth via its coupling to the ICP.

The hearing aids of the present invention also employ a probe channel to allow probe insertion and subsequent acoustic measurement within the channel by the probe measurement measurement system as shown in FIGS. 19-22. The conventional method for making measurements within the canal with a hearing aid involves placing probes under the hearing aid, which causes the probe to be crushed, thus affecting the accuracy of the measurement. Additionally, placing the bass probe of the auditory parts creates an acoustic leak path that causes oscillatory auditory distortion. The channel of the probe of the present invention also provides an improved method for introducing a probe while the hearing prosthesis is placed within the ear canal.

The sequence of these faces as highlighted in fig. 33 represents a unique adjustment process of the present invention. The adjustment process offered by the virtual electroacoustic audiometer system in the prototype of the present invention is implemented in five phases .. (1) reference measurements 264, (2) hearing evaluation without prosthesis 265, (3) assessment of the predetermined prosthesis 266, (4) evaluation of prosthesis Simulated RQ (267), and (5) evaluation with prosthesis 268 ,. However, the individual phases or the components of each phase can be administered individually, or in another sequence, as is adjustable for the individual subjected to the auditory evaluation. Each process phase is implemented in a graphic module, as shown in Figures 24-28. The first phase, for example, reference measurements, is implemented by a reference measurement module (Fig. 24) that contains a window with the reference measurements (shown in Fig. 24) and a model window of signal (shown iconized in fig, 24) The reference measurements window allows the measurement of several transfer functions that are subsequently used, through the adjustment process.

The transfer function without prosthesis Hua (Pn, jw) described above, is measured when choosing the option of 3D-REUR (Response Without Prosthesis of Real Ear of 3 dimensions) The measurements are obtained from the frontal orientations (front speaker # 1) or rear (with your back to speaker # 1), depending on the selected option: Front / Rear. The transfer functions of the left and right ears can be carried out either in the sagittal or transverse plane. Fig.24 shows a set of 8 pairs (pn w) of transfer functions in the transverse plane. The measurement is carried out when placing the individual "N in a manner centered on the formation of loudspeakers (discussed above) and place the right and left probes in the respective auditory channels.

Another new function of the invention is the ability to measure and quantify the occlusion effect of the simulated auditory prosthesis, as well as the fitted hearing aid. However, before the occlusion measurement is taken, a reference measurement should be made with the canal without obstruction. The procedure briefly described herein, requires that the individual utters a vowel, preferably a vowel with a lot of energy content is its low frequency spectrum, such as "ee". A measurement is taken with the probe placed near the eardrum. The measurement of the occlusion effect, for example when there is no obstruction, is stored to measure the reference of the occlusion effect with the clogged auditory canal, using the ICP hearing aid, as explained above.

The transfer function of the surface plate Hfp (pn w) is measured by selecting the Surface Board Response option. The ICP is placed inside the ear and the probe is placed in the microphone position 132 of the surface plate, as shown in Fig. 13. For the real ear transfer function, the ICP receiver, Hicp-rec is measured when the Calibrate ICP option is chosen. This requires that the tube be inserted into the channel of the ICP probe, and the tip of the tube near the eardrum membrane.

To facilitate the proper placement of the probe in the ear canal during the different calibration and response measurements, a novel method is used to optimize said probe placement within the channel, and specifically to minimize the effects of the waves remaining in the channel auditory due to wave reflections from the eardrum. The trajectories of the waves that remain dependent on the frequency are well characterized and are known to those skilled in the art. The new method of the invention involves the acoustic presentation of a dual tone, one at a low frequency in the range of 1kHz to 5kHz, and the second at a range of 15 kHz to 20 kHz. The acoustic response to the tone signals sent either via the speaker or the ICP receiver, which are dependent on the measurement, is measured continuously by a probe system with microphone and shown on the monitor, as shown in Figures 30-32. .

The acoustic response in an ear of an individual for each tone, shown in fig. 29, shows a characteristic increase in the response to low frequency and a decrease in the response to high frequency as the probe approaches the tympanic membrane. The descent occurs approximately 5 mm from the tympanic membrane in the 15 kHz tone. The monitoring of the relative response characteristics during the insertion of the probe provides a visual method and with the assistance of a computer to indicate the proper placement of the probe, as shown in the spectra of Figures 30-32. The end of this procedure is generally indicated when there is a significant decrease, commonly exceeding 15 dB as shown in fig. 31, followed by a significant increase in the high frequency, for example, in response to the second tone.

The low frequency, for example, response to the second tone, shows only a small increase within 3 dB, as the probe is inserted closer to the tympanic membrane. Although the approximation distance of the tip of the probe to the tympanic membrane is possible with this procedure, the object of this procedure is to place the probe in such a way that the least amount of permanent waves are present in the frequencies of interest during the measurement of the transfer function. For example, if a non-prosthetic response measurement of more than 6kHz is desired, inserting the probe until a 15kHz response decrease is detected ensures that measurement errors do not exceed 2.5dB at 6kHz. Accuracy can be increased by selecting higher frequencies for the second tone, although this increases the possibility of advancing the probe too far, which results in touching the surface of the tympanic membrane, an event that is not dangerous but can be uncomfortable Other combinations of tones can be used, including simple, triple, composite signals, to implement the procedure described above consisting of constantly measuring the response to different acoustic stimuli and detecting an appropriate stopping point during the progress of the probe, paying little attention to the distance of the probe from the tympanic membrane. The proper position of the probe will be referred to hereinafter as the reference point of the probe. A second phase, evaluation without prosthesis, is implemented by the evaluation module without prosthesis, shown in figure 25, which consists of an analysis window without prosthesis, which is shown open in figure 25; a spatialization window., which is also shown open; a sale of signal model, it is shown iconized; an audiometric evaluation window, also shown iconized.

The window of analysis without prosthesis allows several measurements and samples of hearing evaluation without prosthesis, while the ICP is inserted into the auditory canal. Measurements include audiogram spectrum, distortion, time analysis, spectogram and 2-CC curves. The stimuli, the measurement methods and the signals associated with these tests are known to those skilled in the art. However, the spectogram of auditory capacity is a new form that is unique in the present invention.

The spectogram of the auditory capacity is a spectrum that shows the audibility of a signal with respect to the auditory profile of an individual and the forms of critical audibility of an acoustic signal. The audibility spectrogram is essentially a three-dimensional matrix represented in a two-dimensional scheme that indicates signal dynamics (time), and Critical Audition Regions (CAR) vs. frequency, as shown in Fig. 25 The CARs are specific to each signal segment that is selected from the signal model window. The CARs of a segment of a conversation are defined by the forms of critical sound, such as the energy of significant formats in vowels, the energy of fundamental frequencies in voices, the energy of sounds of non-periodic frequency, and other criteria that are known to affect intelligibility, detection, or identification, depending on the selected signal model.

The Audibility Spectogram is the result of the combination of signal spectrograms analyzed and the CARs defined, and the spectrograms measured with a probe, computed and compared with the measured auditory profile of an individual in CARs. The values of the spectogram that fall below the auditory threshold are named Values Below the Threshold (B-Threshold) that defines the region of the outer profile, and the values of the spectrograms that exceed the uncomfortable volume level (UCL9 of an individual are nominated as Strong Uncomfortable Volume Levels (A-UCL), which defines the most internal contour regions.Color-code output signals are shaded at the contour for the speech signals.However, any type of acoustic signal may be assigned to CARs and the corresponding audibility spectrogram based on the auditory profile of a specific individual The objective of the audibility spectrogram is to provide a means to make graphs, quickly, that indicate the hearing dynamics received from acoustic signals taking in consideration of the auditory profile of the individuals and the critical hearing forms of a signal model. rticulatmente important in the process of optimization of adjustment during the evaluation of certain prosthesis, simulated prosthesis, and without prosthesis. The spatialization window allows selecting the way to present the signal, either spatially or in intracranial modes. The spatialized mode presents selected sources and ambient signals to be sent to both ears via the ICP's inserted according to the selected spatial relationship of head, sources, environment, and boundaries, as shown in Fig. 25. The spatial relationships they include the distance between the audio source and the reference point of the head (d) angle of azimuth, and angle of altitude (.

Several individuals and calibrations of transfer functions are used to synthesize audio signals with realistic hearing effects. Select signal sources and their corresponding volumes from the Signal Model window (not shown). On the other hand, the intracranial mode offers a conventional sound presentation method where the signals selected were selected signals and the corresponding volumes are sent without spatialization to one or both ears.

The Signal Model Window allows the selection of source and ambient signals and their corresponding volume. The selection source can be pure tone type, conversation, music, or any sign of audiological importance. Environmental signals are commonly words, environmental noise and other signals of audiological importance. The level of the signals selected in the spatialized mode is preferably in dB SPL calibrated at 1 meter from the source in the free field. In-channel acoustic response measurement is preferably shown in dB SPL, as measured by the probe microphone system. In the intracranial mode, environmental and source signals are conducted to the left, right ear, or both as in traditional audiometry. The level of the signals selected in the intracranial mode is preferably in dB SPL. Additionally, measurements taken via the microphone probe system can be made as needed to ensure that the probe and the ICP remain properly positioned in the ear canal. .

A specific selection of types of source and environmental signals, volumes and spatialization mode is defined as a model signal. One or more model signals can be selected, recorded, and retrieved by the system for analysis and presentation purposes. A model signal can represent an individual acoustic signal / stage or combination, including words, noise, music, pure tones, hidden noise, composite signals and other significant audible signals.

The audiometric evaluation window, shown iconized, allows different conventional audiometric measurements to be taken. This includes threshold audiogram, maximum comfort level (MCL), uncomfortable volume level (UCL), conversation reception threshold (SRT), and different audiometric measures known to audiology technicians. However, differently from conventional audiometry, where the transducers are calibrated in several acoustic couplers and the measurements are made in terms of relative auditory volume (HL), the end method measures the response within the channel, in terms of absolute sound pressure level (SPL).

Another form of the invention relates to the modes of presentation of the audiometric signal. As described above, the spatialized or intracranial hearing modes selected from the spatialization window affect not only the selected presentation of the Model signal window, but also the Audiometric Evaluation window. For example, a list of standard audiological words such as NU6 or W22, commonly used in conventional speech audiometry, may be presented in conventional intracranial mode, or alternatively, in the single spatialized mode of the present invention.

The signaling process of a spatialized evaluation without prosthesis involves the transfer function without prosthesis Hua (pnjw), interpolated, based on the selections of the spatialization window, and the transfer function Hicp-rec (jw). The implementation of a signal process of an evaluation without particular spatialized prosthesis is shown in Fig. 10.

The third phase, the predetermined prosthesis evaluation, is implemented by the predetermined prosthesis evaluation module.

This module, shown in Fig. 26, allows the operator to select a hearing aid and predetermine its behavior without involving the individual with hearing disability. The module consists of a selection window / Auditory prosthesis adjustment, in open mode; a Default Analysis window (shown open); a Model Signal Window, shown iconized; a spatialization window, shown iconized; and the Audiometrica evaluation module. The model signal windows, spatialization, and Audiometric evaluation are essentially identical to those described in the evaluation phase without prosthesis.

The Selection / Adjustment of Hearing Prosthetics window allows the selection of an auditory prosthesis and subsequently its adjustment. The default selection / adjustment results are displayed in the selected schemas of the adjacent Default Analysis window. The selection of hearing aids can be automatic or manual, depending on the option selected Automatic Manual. Automatic selection involves selecting one or more hearing aids based on the selected adjustment algorithm, and other criteria selected by the patient and physician. The methods and formulas of conventional adjustment are provided, such as POGO, Berger, and NAL-I I. 7n The prototype fitting method is the dynamic audibility method, which employs a rational one in such a way that the Audibility Spectogram is optimized. This corresponds to the schemes that maximize the Up-Threshold contour areas while minimizing the contour areas of the Down-Threshold (B-Thresh) and the Up-Uncomfortable (A-UCL) auditory levels. The models of hearing aids that better match the models of hearing aids are automatically recovered from the system's memory.

Alternatively, a manual selection can be made by choosing one or more models of hearing aids from the available model list. An auditory prosthesis model contains all the necessary electroacoustic parameters that are used for the signal processing of a signal model. The results of the signal process are used in the Predetermined Analysis window, for analysis and signaling purposes. The hearing prosthesis parameters of a selected hearing prosthesis model are adjusted manually or automatically depending on the Auto / Mandual adjustment option and the selected adjustment method.

There is usually a unique set of auditory prosthesis control parameters for the selected hearing aid model. In the example Fig. 26 with the selected GigiLink 100 hearing aid model, the control parameters are: volume control (VC), low frequency cut (LFL), compression threshold (TK), microphone type (MIC) ), Receiver Type (REC), and Aperture Size selection, which reflects the size of the ICP output aperture inserted. If a different exit opening size is selected, either manually via the opening selection of insertion output, or electronically via the selection of the programmable micro-valve, a new transfer function Hicp-spkr (jw) is measured, for improve the accuracy of the analyzes.

The default analysis window is essentially identical to the analysis window if prosthesis, described above, with the exception of the signal processor model that includes the transfer function measured on the surface plate (292.293; Fig. 33), the transfer function of hearing aid Hha (jw) (294; Fig. 33) and the ICP receiver measured for the real ear transfer function Hicp-rec (jw) for hearing aids (295; Fig.33). The transfer function is typically non-linear and varies depending on the selected hearing aid. The transfer function of the total hearing aid Hha-t (jw), normally includes microphone transfer functions Hmicíjw), hearing prosthesis circuit Hha-rec (jw), and receiver Hha-rec (jw). The transfer function Hha (jw) differs from Hha-t (jw) by excluding the hearing aid receiver and, instead, by including the Hrec-corr receptor correction transfer function (jw), which defines the difference between the receiver of predetermined hearing aid and the ICP receiver used. This correction transfer function Hrec-corrQw) is typically a linear transfer function and is supplied by the VEA system.

Fig. 33 shows the process of analysis of the predetermined prosthesis for a right ear with prosthesis and left ear without prosthesis for a master / talking, child / listening scenario. The results of the digital signal process are stored in the memory of the system 106 for analysis and for display.

The analysis of the predetermined data in the system memory includes the audibility analysis described above. The schemes include an Audibility spectogram that indicates the hearing profiles in Threshold-Low, Threshold-High and High UCL with respect to the critical hearing regions (CRAs). Fig. 26 shows an improvement of hearing in the predetermined prosthesis condition vrs the condition without prosthesis shown in Fig. 25, for example, areas of contour of High Threshold increased.

Another unique predictive measure of the present invention is the measurement of the occlusion effect caused by the insertion of the ICP into the auditory canal which is characterized by the perceived amplification of the person's own voice. The present invention provides a method for objectively and objectively measuring the magnitude of the occlusion effect. The subjective method is carried out by asking the individual who uses the ICP to evaluate their own voice when speaking. If the answer is inconvenient for the candidate for the hearing aid, another alternative PCI should be considered that represents a different hearing aid.

The objective method involves measuring the response via the probe system in the obstructed auditory canal and subtracting the reference measurement from the obstruction effect, for example, measuring the auditory canal without obstruction, as described above.

The microphone of patient 57, external to the left ear, is normally used to record the individual's own voice during occlusion effect measurements to ensure constant intensity volume while both the measurement of the obstructed auditory canal and the measurement are carried out. of the non-obstructed auditory canal (see Mueller, HG, Hawkins, DB, Northern, JL :, Probe Microphone Measurements: Hearing Aid Selection and Assessment, 1992, pp.221-224). A unique way of the present invention is to eliminate not only the constant voice intensity requirement, but also the constant speech spectrum characteristics.

This is done by adjusting the measure of the occlusion effect calculated by the difference in the spectral characteristics of the individual's own voice.

It is known in the field of audiology that deep insertion of the hearing aid substantially reduces the occlusion effect, particularly at low frequencies in the range of 125 to 1000 Hz. Therefore, a smaller ICP, resulting in a prosthesis smaller auditory, can be used for the subsequent evaluation phases.

The obstruction effect created by two types of ICP, for example, ICP-1TC and ICP-ITE, is shown in the scheme of Fig. 27. This scheme represents an important obstruction effect due to ICP-ITE vrs ICP-ICP of an individual. This is expected, since the ICP-ITE transfer measure creates a larger residual volume, and the clogging effect is directly proportional.

The advantage of measuring the ICP at the reference point of the probe is that all measurements taken are independent of selected ICP or its placement in the ear canal. However, to present accurate spatialized sounds to the individual, it is required to measure the Hicp-re (jw) transfer when a new ICP is selected and inserted into an individual's ear canal.

Another measure unique to the invention is that of auditory acoustic distortion caused by acoustic leakage from the ICP receiver to the surface plate of the ICP, when simulating an auditory prosthesis receiver. The transfer function Hicp-fb (jw) (338; Fig. 37, for example, amplitude and phase response, is measured on the surface plate, as described above, The aperture created by removing the probe from the probe channel of the ICP is preferably obstructed during the measurement of auditory distortion to prevent acoustic leakage due to the probe channel.

An important application of the transfer function is the simulation, and consequently the prediction, of oscillatory feedback of the simulated auditory prosthesis. This undesirable oscillatory auditory distortion manifests in the form of whistling, which interferes with the normal functioning of the hearing aid. The predetermination and simulation of the oscillatory auditory distortion of a simulated auditory prosthesis is carried out by incorporating the ICP auditory distortion transfer function Hicp-fb (jw) 337, as shown in Fig. 37.

Oscillatory auditory distortion may be audible to the individual carrying the ICP via the ICP receiver. Oscillatory auditory distortion can also be measured via the ICP microphone system in conjunction with the VEA system. This procedure allows the operator to adjust the simulated auditory prosthesis in particular, the increase, frequency response, exit opening size, so that the oscillatory auditory distortion is eliminated or minimized. Similarly, the VEA system can be used to automatically select a hearing aid alternative or alter the set of auditory prosthesis parameters, so that the oscillatory auditory distortion is minimized or eliminated.

The analysis window of the predetermined prosthesis also includes other analyzes and its corresponding diagrams of Audiogram, Distortion, Time Analysis, Espectogram, Curve 2-cc. These are standardized measures and schemes that are known to the technicians in the field. The 2-cc coupling curves involve the conversion of in-channel measured responses to 2-cc coupling curves, using 2cc real-ear conversion formulas. Standard signal models, such as pure tones are commonly involved in 2-cc coupling measurements (see Auditory Prosthesis Characteristics Specification, ANSI-S3.22-1987, American Standards National Institute). Other methods of evaluation include the measurement of the Articulation Index (Al) in the following conditions: with prosthesis, without prosthesis and with simulated prosthesis.

One objective of the predetermined prosthesis module is to objectively predict the performance of a selected hearing aid, a selected hearing aid parameter and the individual's auditory profile, without the participation of the individual with hearing impairment.

The fourth phase, evaluation of simulated prosthesis, is implemented by the simulated prosthesis evaluation module, as shown in Fig. 27. This module allows the operator to select and optimize one or more hearing aids and stimulate auditory characteristics. The module consists of a hearing prosthesis simulation window, shown open, a Simulated Prosthetics Analysis window, shown open, a Model Signal window, shown iconized. The Model Signal, Spacialization, and Audiometric Evaluation windows are essentially identical to those described above. The Simulated Prosthetics window is essentially the same as the Select / Adjust Auditory prosthesis window of the Hearing Prosthetics Evaluation module. Similarly, the Simulated Protesis analysis is essentially identical to the Default Analysis window.

A greater difference in the evaluation module of simulated prostheses in the capacity of the module to synthesize simulated prosthesis conditions, and the presentation of auditory results to the individual with auditory disability. Another significant difference is that the analysis 7ft carries out the module based on measured data, instead of predetermined data. The response is obtained via the measuring system of the microphone probe, with the end of the probe placed at the reference point of the probe, as described above.

An example of a simulated prosthesis signal process, shown in Fig. 34, includes the auditory transfer function Hha (jw) which includes the transfer function Hrec-corr (jw), and the function of transfer of superficial plates Hfp (pn , jw) to simulate the prosthesis of the ear ,. The results of the process are converted to analog signals via the converter from digital to analogue 115 and driven to the left and right ICPs, 119 n and 120 respectively, inserted into the ear canals of an individual.

If the microphone of the predetermined hearing aid is of a directional type, the separate microphone transfer functions, which represent its directional properties, are employed, as shown in FIG. 35. A digital audio file 107 is retrieved from the system memory. 106 and is processed with the surface plate transfer functions Hfp (p1, jw) (310; Fig 35) and Hfp (P2, jw) (312; Fuig.35), where p1 and p2 represent two points in space Three-dimensional The signal pathways from p1 to p2 can represent direct and primary reflective trajectories, respectively. The secondary relective trajectories p3, p4 ..., pn (not shown) can be represented in a similar manner in the digital signal process.

The results of each step of the surface plate transferecnia function are subsequently processed with the auditory prosthesis circuit transfer function Hha-cir (jw) 322, Hrec-corr (jw) 324, as shown in Fig. 35 . The resulting processed digital signal is converted into an analog signal, via the digital to analog converter 115 and conducted to the appropriate ICP within the auditory channel via the audiometric transduction interface 117.

The simulated hearing aid analysis window includes the measurement and corresponding diagram of Audiogram, Distortion, Time Analysis, Spectomogram, Hearing Spectogram, 2-cc Curve, Obstruction Effects, and Auditory Distortion Analysis. These measurements are essentially identical to those described above in the default analysis window. This process is based on the ability of the system to compute an auditory prosthesis prescription based on a prescription of selected formula / rational adjustment. This selected hearing aid can be adjusted and the results analyzed with or without the participation of the hearing impaired individual. an An objective of the hearing prosthesis module is to optimize, in an objective and subjective manner, the operation of a hearing aid selected according to the response of the probe within the measured channel, as a function of the selected signal model, of the auditory prosthesis parameter, the auditory profile of the individual and the subjective responses to the audible signals presented.

A unique form of the present invention is the ability to compute the characteristics of a simulated, monaural or binaural hearing aid system that produces natural sound perception and an improved sound localization capability for the disabled individual. This is accomplished by selecting the simulated auditory prosthesis transfer function that produces, in conjunction with the plate-surface transfer function, a combined transfer function that matches the transfer function without prosthesis of each ear. The requirement to match normally includes phase and frequency responses. However, the magnitude of the response is expected to vary, since most individuals with hearing impairment require amplification to compensate for hearing loss.

Once the processes of selection and optimization of hearing prosthesis have been carried out via the simulation of the VEA system, the characteristics of the simulated auditory prosthesis are transferred to specifications of auditory prosthesis for its manufacture or assembly. Manufacturing specifications include: auditory prosthesis components simulated by the VEA system, including the microphone and receiver, shape and size of the hearing aid according to the selected ICP, auditory prosthesis circuit blocks and circuits; placement of auditory prosthesis parameters; and size and type of exit opening. One objective of the VEA system is to provide a detailed specification to the manufacturer to manufacture a mono or binaural that equals as much as possible the chosen simulated hearing aid. The order of the hearing aid is carried out in the Order menu shown in Fig. 27 which provides an impression of the detailed specification of the hearing aid.

The final step in the process, the assessment of the prosthesis, is represented by the prosthesis evaluation module shown in Fig. 28. This module consists of a Prosthetics Evaluation window, shown open, a Prosthetics window analyzed, shown open; an Audiometric Evaluation window, shown iconized; a Signal Model window, shown iconized, a Spatialization window, shown iconized. The last three windows are essentially identical to the windows of the evaluation of the predetermined prosthesis and evaluation of the simulated prosthesis, the window of evaluation of the prosthesis allows the electronic adjustment of the parameters of the hearing prosthesis manufactured as in the case of a programmable hearing aid, shown in Fig. 21, or showing the adjustment of the suggested parameters in the case of manually adjusted hearing aids. Shown in Fig.20.

The prosthesis analysis window is similar to the window of analysis of the steps of the evaluation process of simulated prosthesis, predetermined and without prosthesis, except that the measurements and the corresponding schemes reflect the response of the auditory apparatus inserted inside the auditory canal of the individual instead of reflecting the synthesized or predetermined signal, for example, simulated prosthesis response analysis.

Realistic, synthesized acoustic signals are presented in the hearing aid by coupling spatialized sounds directly to the microphone of the hearing aid, as shown in Figures 19-21. The surface plate transfer function, Hfp (Pnjw), and the transfer function supplied from ICP receiver to microphone Hicp-mic Qw) are used in the processes of digital synthesis, as shown in Fig. 36. A file of digital audio 107 representing an audio source at the location in the space pn is retrieved from the memory of the system 106 for processing with the field-free surface plate transfer function Hfp (Pn, jw) 340, 342 for the left ears and right, individually. Other parallel processes that reflect the filtering of additional audio sources or filtering of reflective paths, are shown collectively in the striped rectangles 341, 343, are added with the right nodes 112 and left 113. The output of the added nodes is subsequently processed to Equalizing the ICP receiver for the purpose of coupling the hearing aid microphone by applying the reverse transfer function 1 / Hicp-mic (jw) 344, 345. The acoustic signals sent to the microphone 350 of the auditory prosthesis 351 represent spatialized signals with characteristics selected and controlled by the VEA system operator via the Spatialization, Signal Module, and Audiometric Evaluation windows.

The electroacoustic tests of the hearing aid, coupled to the ICP as described above, can also be carried out externally to the ear canal, for example, 2-cc measurements can be taken by connecting the receiver output of the hearing aid to the hearing aid. 2cc coupler input. The ICP, in conjunction with the signal generation capability of the VEA, can produce various acoustic stimuli as an output during the evaluation of auditory prosthesis based on the 2-cc coupler. Similarly, the 2-cc coupler measurements can be carried out in the ICP, for example, a simulated hearing aid, by connecting the output of the ICP receiver to the input of the 2-cc coupler.

The invention not only solves the current problems of adjustment and diagnosis, but also provides bases for new tools that are audiologically significant. For example, the ability of the system to synthesize realistic acoustic conditions, both for simulated prostheses and prostheses, can be used as an auditory rehabilitation tool where the hearing ability of the disabled individual is enhanced by interactive training. In this application, the person with hearing disability receives spatial signals that represent spoken words with environmental noise. Although the words may be audible as determined from the hearing measurements and methods described above, these words may not be intelligible to untrained individuals with disabilities. Depending on the verbal response, or the response recorded via a response key, the VEA system can provide visual or acoustic auditory distortion to the disabled individual, which indicates whether the response is appropriate. The objective of this new test is to teach disabled individuals how to improve word perception and intelligibility beyond mere listening. Another test of the present invention determines the ability of an individual to locate a sound on a three-dimensional spatial plane. One example is the detection of the minimum audibility angle (MAA), which tests the ability of the individual to detect, in degrees, the minimum angular separation of pure tones vs. frequency (see Mills, AW, On the Minimum Audible Angle, Journal of Acous, Soc of Am. 30: 237-246, 1956). Additionally, the localization capacity of the individual can be compared, under conditions with prosthesis, without prosthesis and with simulated prosthesis.

The invention also makes it possible to determine the ability of the individual to detect sound movements in a plane or three-dimensional space. For example, the sound of an object can be synthesized to represent a movement in a particular geometric and frequency pattern. The ability of the disabled individual to detect movement can be assessed. Additionally, the ability to detect the movement of the individual can be compared, under conditions with prosthesis, without prosthesis and with simulated prosthesis.

Although the present invention is described in relation to the prototype, those skilled in the art will readily appreciate that other applications may be substituted without departing from the scope of the present invention. Therefore, the invention should not be limited exclusively to the Claims included below.

Rfi

Claims (23)

1. - A system for the evaluation of auditory function in humans, comprising: an intracanal prosthesis to reproduce synthesized acoustic signals and to measure the in-canal acoustic response near the eardrum, to perform an auditory evaluation, prosthesis prescription auditory, simulation of auditory prosthesis, and adjustment of auditory prosthesis.

2. The System of Claim 1, wherein said system simultaneously provides signals and measurement.

3. - A method to evaluate the human auditory function, including the steps of: Reproduce synthesized acoustic signals and measure the acoustic response within the canal near the eardrum to perform: an auditory evaluation, hearing prosthesis prescription, prosthesis simulation auditory, and adjustment of auditory prosthesis.

4. - The method of claim 3, further comprising the step of directly and acoustically coupling the intracanal prosthesis to an auditory prosthesis microphone for evaluation of hearing prosthesis.

5. -An intracranial prosthesis comprising: a receiver to transmit acoustic signals to the membrane of the eardrum of individuals; and a microphone system for transmitting acoustic signals from said auditory channel and for providing electrical signals representative of said acoustic signals.

6. The intracranial prosthesis of Claim 5, further comprising: means for placing a tube within the ear canal to minimize the effects of outgoing waves to measure a desired bandwidth

7. - The intracranial prosthesis of claim 5, further comprising: a ventilation channel to equalize the pressure of said intracranial prosthesis.

8. - The intracranial prosthesis of claim 7, said ear canal further comprising: inserting a selected air passage to vary the acoustic characteristics of said intracranial prosthesis.

9. - The intracranial prosthesis of Claim 8, wherein the air passage is preferably long to reduce or eliminate the occlusion effect; and alternatively that the air passage is preferably small, to reduce or eliminate the acoustic leakage of said receiver.

10. The intracranial prosthesis of Claim 5, wherein the probe microphone system comprises: a probe tube; and a probe microphone to measure the acoustic response resulting from the unique interaction between the acoustic stimuli produced by said receiver and the characteristics of the auditory canal of the individual.

11. - The intracranial prosthesis of claim 5, further comprising: a container adapted for placement in the superficial auditory canal, said container representing auditory prostheses to be placed on the surface of the auditory canal.

12. - The intracranial prosthesis of claim 5, further comprising: a container adapted for placement in the deep auditory canal, said container representing auditory prosthesis to be placed in the depth of the ear canal.

13. - The intracranial prosthesis of Claim 5, further comprising: a central portion; and a mango portion.

14. - The intracranial prosthesis of Claim 13, wherein said handle is disposable.

15. - The intracranial prosthesis of Claim 5, further comprising: an acoustic baffle to provide an acoustic seal.

16. - The intracranial prosthesis of Claim 7, further comprising: A ventilation channel that is electronically adjustable in situ.

17. - The intracranial prosthesis of claim 5, further comprising: Directly and acoustically coupling the intracanal prosthesis to an auditory prosthesis microphone for the evaluation of auditory prosthesis.

18. - The intracranial prosthesis of Claim 17, wherein the direct acoustic coupling is carried out by magnetic attraction.

19. - The intracranial prosthesis of Claim 17, wherein the direct acoustic coupling is carried out by an acoustic coupler.

20. - The intracranial prosthesis of Claim 5, further comprising a positioning handle

21. The intracranial prosthesis of Claim 5, further comprising: at least one probe holder on a surface plate of the intracranial prosthesis for measuring the surface plate transfer function.

22. The intracranial prosthesis of Claim 5, further comprising: at least one probe holder on a surface plate of the intracranial prosthesis for measuring the acoustic feedback transfer function.

23. - A system for simulating an auditory prosthesis, comprising: an intracranial prosthesis to reproduce acoustic signals and to measure the acoustic response in the ear canal near the eardrum, said intracanal prosthesis configured to simulate the physical and electroacoustic characteristics of an auditory apparatus . 99