Patent Application
20090274314
This application claims priority of German Patent Application No. 10 2008 021 613.5 DE filed Apr. 30, 2008, which is incorporated by reference herein in its entirety.
The invention relates to a method for determining a degree of closure in a hearing device and a hearing device for determining a degree of closure.
To accommodate the aesthetic requirements of a wearer of a hearing device, said hearing device is to be as inconspicuous as possible on the wearer from the outside. The miniaturization of the hearing devices thus necessary on the one hand and as versatile a functional range as possible on the other hand as well as a high-quality processing of the signals needed to improve the audibility within the hearing devices represent different requirements.
With hearing devices, a closure effect, the so-called occlusion, which is perceived by the wearer as unpleasant, may occur, since the space for a pressure equalization hole, the so-called vent, is frequently not sufficiently large. As a result of this closure effect, the actual voice of the hearing device wearer sounds louder and hollow. The occlusion effect takes place for instance by means of an in-the-ear hearing device inserted into the ear or by means of an otoplastic of a behind-the-ear hearing device.
Vents with a diameter of up to 1 mm are almost exclusively used to equalize the pressure when inserting an in-the-ear hearing device into the ear and/or into a part of the hearing device to be inserted into the ear. These small vents are also used to equalize the pressure in the case of temporally short pressure fluctuations in the surroundings, like for instance may occur in an aeroplane, when closing doors, in an elevator or when swallowing. Vents with a larger diameter have a huge influence on the low tone frequency path, but nevertheless also reduce the occlusion effect in the auditory canal, if the hearing device is positioned in the ear or on the auricle and therefore at least partially blocks the outer auditory canal.
All bores and channels in a hearing device are to be regarded acoustically as “long tubes” and exhibit low pass characters, i.e. they may allow low frequencies to “escape”. Bores with a larger diameter have greater cut-off frequencies and a more minimal damping. In this way a necessary sound separation function between a receiver of the hearing device or a radiating sound tube and an ambient microphone can however no longer be fulfilled in the vicinity of the ear from a certain acoustic amplification, as a result of which acoustic feedback occurs, a “whistling”. This acoustic feedback also depends on the diameter of the vent.
To measure the degree of occlusion, an open loop gain measurement can be implemented for instance as in the patent application DE 10 2006 042 083 A1. With this, the open loop amplification is determined by way of the frequency between a receiver and a microphone, which rests against the side facing away from the auditory path and is compared with stored reference curves.
To counteract the occlusion, the acoustic feedback but also other acoustic problems in the case of a hearing device, methods and apparatuses are known, which record the acoustic conditions in the exterior auditory canal using an auditory canal microphone and make a signal processing available within the hearing aid device. The patent application DE 10 2006 047 965 A1 specifies a method in this regard. The sensation of occlusion in the case of a hearing device wearer can be reduced with the aid of this active occlusion reduction despite a small vent diameter. In order to adjust the active occlusion reduction to the acoustics of the individual auditory canal of the hearing device wearer, an initialization measurement must be carried out on the ear of the wearer. This measurement is to indicate the effectiveness of the occlusion reduction. Due to the complexity and the depth of incoming measurement data, an appropriate interpretation by means of a hearing device acoustician is difficult and/or not possible, since the knowledge needed for the active occlusion reduction is understandably not available to him/her.
An object of the invention is to specify a method and an apparatus, with which an interpretation of the initialization measurement, in particular for a hearing device acoustician, is easily possible.
In accordance with the invention, the set object is achieved with a method and a hearing device as claimed in the claims.
The object is achieved by a method for determining a degree of closure in a hearing device comprising at least one auditory canal microphone and at least one receiver. The method includes an in-situ measurement of a transmission function between the receiver and the auditory microphone, a comparison of the measured transmission function with previously determined reference values and/or curves and a determination of an effective vent diameter from the comparison, with the effective vent diameter specifying the degree of closure. The previously determined reference values and/or reference curves may have been determined theoretically or empirically for instance. This is advantageous in that a very apparent and easily interpretable variable, namely the effective vent diameter, is available instead of a very abstract result of an initialization measurement. This is also understandable for a hearing device acoustician.
In a further embodiment, the hearing device may comprise active occlusion suppression. A transmission function with switched-off active occlusion suppression can be measured, the measured transmission function can be compared with a maximum effect of the active occlusion suppression and a theoretical, maximally effective vent diameter can be determined from the comparison. As a result, it is possible to determine which maximum improvement is theoretically possible by means of active occlusion suppression.
In one development, the hearing device may include an active occlusion suppression, a first transmission function with a switched-off active occlusion suppression and a second transmission function with a switched-on active occlusion suppression can be measured, a first and a second effective vent diameter can be determined, the first can be compared with the second effective vent diameter and a quality factor of the active occlusion suppression can be determined from the comparison. This is advantageous in that active occlusion suppression can be evaluated easily.
A quality measure of the active occlusion suppression can preferably be determined from a comparison of the theoretical, maximally effective vent diameter using the second effective vent diameter. This determines the scope in which active occlusion suppression can in practice achieve its theoretical effects.
In a further embodiment, the hearing device can be switched to implementing the in-situ measurement and determining an effective vent diameter in a measuring mode. Outer influences are as a result eliminated.
The effective vent diameter for information and/or documentation can also be output by way of a hearing device interface. The value is thus easily accessible for a hearing device acoustician for instance.
In a further embodiment, the method can be exclusively implemented with means of the hearing device. This is advantageous in that no additional measuring devices are needed.
A hearing device for determining a degree of closure with at least one auditory canal microphone and at least one receiver is also specified, with the hearing device including a control and storage unit for implementing the method, with the receiver and the auditory canal microphone being linked to the control and storage unit.
In one development, acoustic measuring signals can be output by the receiver.
In a further embodiment, the acoustic measuring signals output by the receiver and/or reflected in the auditory canal can be recorded by the auditory canal microphone.
Further details and advantages of the invention are apparent from the explanations below of several exemplary embodiments with reference to schematic drawings, in which:
The key components of hearing devices are principally an input converter, an amplifier and an output converter. The input converter is normally a receiving transducer e.g. a microphone and/or an electromagnetic receiver, e.g. an induction coil. The output converter is most frequently realized as an electroacoustic converter e.g. a miniature loudspeaker, or as an electromechanical converter e.g. a bone conduction hearing aid. The amplifier is usually integrated into a signal processing unit.
This basic configuration is illustrated in
In the case of an inserted hearing device, measuring signals and/or measuring signal sequences are emitted by the receiver 2 into the auditory canal 9 in order to determine a degree of closure in the in-the-ear hearing device 10. These measuring acoustic signals are reflected in the auditory canal 9 and on the eardrum and then reach the auditory canal microphone 1. The control and storage unit 4 evaluates these measuring signals received by the auditory canal microphone 1 by determining a transmission function from the measuring signals received by the auditory canal microphone 1 and comparing these with stored reference transmission functions and/or reference values. The control and storage unit 4 calculates an effective vent diameter EV from this comparison. The effective vent diameter EV is a theoretical measure for the occlusion suppression. It specifies how large the diameter of a physical vent has to be in order to generate the same occlusion suppression effect. The reference data stored in the control and storage unit 4 was either determined theoretically or originates from empirical examinations and/or measurements.
Effective vent diameters EV can be determined with or without switched-on active occlusion suppression.
A flow chart of an additional method is shown in
| Number | Date | Country | Kind |
|---|---|---|---|
| 102008021613.5 | Apr 2008 | DE | national |
