EP0674462A1 - Device for the fitting of programmable hearing aids - Google Patents

Abstract

Data of the user's hearing deficiency are entered (4) in a processor (3) in which a fuzzy logic module (5) includes a calculator (6) operating on these data and on the equipment characteristic (11) in accordance with a rule base (7) and adjustment data retrieved from an additional memory (10). The calculator performs fuzzification (13), inference (14) and defuzzification (15) and is interfaced (12) to the equipment (2) by wired or wireless transmission (1). The rules may be stored in an EEPROM or on a diskette.

Description

The invention relates to a device for adapting programmable hearing aids, comprising a data processing unit that can be coupled to the hearing aid via a signal transmission, into which data characterizing the hearing loss of the hearing device wearer to be supplied can be entered and wherein the data processing unit can also be supplied with characteristic data of the hearing aid or can be called up from a data carrier of the data processing unit .

It is known to adapt hearing aids to the individual hearing loss of the hearing device wearer to be supplied. Furthermore, a setting of the hearing aid is provided for different listening situations. Programmable hearing aids offer a large number of adjustable parameters which are intended to enable the electro-acoustic behavior of the hearing aid to be optimally adapted to the hearing damage to be compensated for. At the same time, however, the adjustment is becoming more and more difficult for the hearing care professional due to this large number of parameters and the resulting variety of possible setting combinations. This can lead to incorrect fitting of the hearing aid or the non-optimal use of all fitting options.

The object of the invention is to provide a device for adapting programmable hearing aids, which enables the best possible adaptation of the hearing aid to the hearing loss, the adaptation itself being simple to carry out and the hearing device-specific properties being optimally usable, taking into account rules which can be specified by the hearing device manufacturer.

According to the invention, this object is achieved in a device of the type mentioned in the introduction in that the data processing unit has a fuzzy logic module, the processor of which processes the input and / or retrievable data and characteristic data, including processing rules, from at least one rule base according to the principle of fuzzy logic, and provides hearing aid setting data as a result.

Advantageously, the hearing care professional is given the opportunity to adapt the hearing aid by having a programming unit implemented according to the principle of fuzzy logic, which, after inputting the audiometric data and the type of hearing aid to be adapted, proposes optimal and sensibly coordinated settings of all hearing aid parameters . These suggested settings can be taken over completely or modified if necessary after further acoustic measurements.

The fuzzy logic module or the data processing unit is e.g. primarily supplied by the hearing aid manufacturer. The rule set of the module can be supplemented by the user of the adaptation device in such a way that further processing rules for determining the hearing aid parameters can be entered into a data carrier of the module, which are based on the acoustician's special experience.

Advantageous embodiments of the invention are characterized by claims 2 to 6.

Further advantages and details of the invention are explained in more detail below with reference to the exemplary embodiments shown in the figures.

• Figur 1 ein Blockschaltbild einer erfindungsgemäßen Einrichtung zur Anpassung programmierbarer Hörgeräte,
• Figuren 2 bis 4 beispielhafte Darstellungen des Grundprinzips für die Anwendung von Fuzzy-Logik bei der Ermittlung von Anpaßparametern eines programmierbaren Hörgerätes.

Show it:

• FIG. 1 shows a block diagram of a device according to the invention for adapting programmable hearing aids,
• Figures 2 to 4 exemplary representations of the basic principle for the use of fuzzy logic in the determination of adaptation parameters of a programmable hearing aid.

The device according to the invention, shown schematically in FIG. 1, for realizing a fuzzy logic system for determining the adaptation parameters for a programmable hearing aid 2 can be implemented in the form of an independent programming device or in combination with a personal computer or in connection with another data processing system. The device comprises a data processing unit 3 which can be coupled to the hearing aid 2 via an interface 12 for signal transmission 1. The signal transmission 1 can take place via a line connection or also wirelessly. The data processing unit 3 or a programming device external to the hearing aid 2 has a fuzzy logic module 5. This module 5 in turn comprises an arithmetic unit 6 or a processor with components for executing the fuzzy logic operations: fuzzification 13, inference formation 14 and defuzzification 15. Furthermore, the fuzzy logic module 5 contains at least one rule base 7. On a data carrier thereof Processing basis for determining hearing aid setting data is stored in a rule base 7 or this set of rules, the data 4 characterizing the respective hearing loss of the hearing aid wearer to be supplied and the characteristic data 11 of the hearing aid 2 to be programmed in each case to be determined for determining the hearing aid setting data / hearing aid parameters in the determination or Calculation of the hearing aid setting data are included. The data 4 relating to the hearing loss of the hearing impaired is entered via an interface 8 to the computing unit 6 of the data processing unit 3 or of the fuzzy logic module 5. 9 denotes a data carrier for the hearing device-specific characteristic data 11, which is also the data processing unit 3 or is assigned to the fuzzy logic module 5 and the hearing device-specific ones specified by the hearing device manufacturer Characteristic data 11 can be supplied to the computing unit 6 or can be called up by the latter.

In the illustrated exemplary embodiment, in addition to the rule base 7, in which the processing rules of the hearing device manufacturer are stored and can be called up, an additional rule base of the hearing aid acoustician is provided, the data carrier 10 of which gives the hearing aid acoustician the possibility of additional storage of processing rules which are derived from personal experience. The acoustician who adapts the hearing aid can determine, change, or correct the processing rules that can be read into the data carrier 10, while the processing rules of the first rule base 7 specified by the manufacturer should not be changeable.

• die werksseitigen Standardeinstellungen für programamierbare Hörgeräte bzw. die einzelnen Hörsituationen übernehmen oder
• Jeden Parameter des Hörgeräts bzw. der Hörsituation einzeln einstellen/modifizieren.

Advantages of the invention:
So far, hearing care professionals have only been able to adapt a programmable hearing aid either

• accept the factory default settings for programmable hearing aids or the individual listening situations or
• Set / modify each parameter of the hearing aid or the hearing situation individually.

The disadvantage of this procedure is that, in the first case, the individual adaptability of the programmable hearing aid is not used at all, or in the second case, despite great adaptation effort, the hearing aid parameters may not be set optimally or even incorrectly.

• Es ist die optimale und sinnvoll aufeinander abgestimmte Einstellung aller Hörgeräteparameter entsprechend den individuellen audiometrischen Daten des Hörschadens nach allgemein gültigen, vom Hörgerätehersteller vorgegebenen und geprüften Regeln möglich.
• Die Einstellung aller Parameter eines programmierbaren Hörgerätes ist eine komplexe Optimierungsaufgabe, die nicht immer in geschlossener, analytischer Form gelöst werden kann. Vielmehr spielen einzelne, aus der Erfahrung gewonnene Regeln hierbei eine wichtige Rolle. Dabei können sich bei entsprechender Konstellation der Eingabedaten und/oder Regelsätze durchaus auch einander teilweise widersprechende Forderungen für die Einstellung einzelner Parameter ergeben. Die Verarbeitung solcher zum Teil widersprüchlicher Teilergebnisse im Sinne eines Gesamtoptimums ist eine inhärente Fähigkeit der Fuzzy-Logik.
• Die in der Anpaßpraxis ermittelten audiometrischen Daten sind im allgemeinen mit relativ großen Toleranzen behaftet. Ein Anpaßmechanismus, welcher nach dem Prinzip der Fuzzy-Logik arbeitet, ist aufgrund der Fuzzyfizierung der Eingabedaten aber inhärent sehr robust gegenüber solchen Toleranzen, d.h. die unpräzisen Eingabedaten führen nicht oder nur geringfügig zu einer Verschlechterung des berechneten Parametersatzes für die Programmierung des Hörgerätes.

The matching device according to the invention, which is based on the principle of fuzzy logic, is distinguished in particular by the following advantages:

• The optimal and sensibly coordinated setting of all hearing aid parameters is possible in accordance with the individual audiometric data of the hearing damage according to generally applicable rules specified and tested by the hearing aid manufacturer.
• The setting of all parameters of a programmable hearing aid is a complex optimization task that cannot always be solved in a closed, analytical form. Rather, individual rules gained from experience play an important role here. Given a corresponding constellation of the input data and / or rule sets, there may also be partially conflicting requirements for the setting of individual parameters. The processing of such partially contradictory partial results in the sense of an overall optimum is an inherent ability of fuzzy logic.
• The audiometric data determined in the fitting practice generally have relatively large tolerances. A fitting mechanism, which works on the principle of fuzzy logic, is inherently very robust against such tolerances due to the fuzzification of the input data, i.e. the imprecise input data does not or only slightly deteriorate the calculated parameter set for programming the hearing aid.

An exemplary explanation of the use of fuzzy logic in determining fitting parameters of a programmable hearing aid is described below with reference to FIGS. 2 to 4.

According to FIGS. 2 to 4, the structure of processing sizes using fuzzy logic is shown as an example. The first step in implementing a fuzzy logic structure is to define the linguistic variables for their input and output variables. For each of these quantities, their terms are plotted on a numerical scale. The variable size A is shown in units above a numerical value scale over the x axis of the coordinate system. The degree of membership is indicated in the y-axis. The "sharp" value A = 2 on the numerical value scale activates, for example, the term "A is very small" with a degree of 0.6 and the term "A is medium" with a degree of 0.2.

The sharp value A = 2 is described after this fuzzification as a fuzzy value (linguistic variable) A with the following set of statements: $$\begin{array}{c}\begin{array}{c}\text{µ (A is very small) = 0.6;}\\ \text{µ (A is medium) = 0.2;}\\ \text{µ (A is large) = 0.0;}\\ \text{µ (A is very large) = 0.0.}\end{array}\end{array}$$

µ is the "degree of fulfillment" or "degree of truth" of the respective statement.

The further processing of the variables in the interior of the fuzzy logic system, in particular their linking according to the rules of the rules (inference), now takes place in this fuzzy representation.

The result of the entire linking operation is converted back to sharp values at the output of the fuzzy logic system (defuzzification).

Regel 1:

if A ist groß and B ist groß then X ist groß and Y ist groß.

Regel 2:

if A ist klein or B ist groß then X ist mittel.

Regel 3:

if A ist klein and B ist klein then Y ist klein.

Figure 3 shows an overview of the logical structure of a fuzzy logic system that implements the following example set of rules:

Rule 1:

if A is big and B is big then X is big and Y is big.

Rule 2:

if A is small or B is large then X is medium.

Rule 3:

if A is small and B is small then Y is small.

Figure 4 illustrates in graphic form the functioning of this fuzzy logic system:
The two sharp input variables A and B are fuzzified in the manner described above. In this example, the two operators and and or are implemented in the most common way as minimum and maximum formation. Other types of realization generally known from the literature could in principle also be considered for this. The degree of fulfillment of the linking operations now activate the terms of the fuzzy output variables to the respective extent. By superimposing the activated terms of each output variable and forming its centroid, the sharp output variables of the fuzzy logic system result. Known methods can be used to implement this last step (defuzzification).

• Hörschwelle bei verschiedenen Frequenzen
• Unbehaglichkeitsschwelle bei verschiedenen Frequenzen
• Ergebnisse von Sprachverständlichkeitstests mit/ohne Störgeräuschen
• Subjektiver Höreindruck des Schwerhörigen im Sinne von Besser/Schlechter-Entscheidungen bei zu vergleichenden Situationen.

Exemplary embodiment for a fuzzy logic system for determining adaptation parameters of a programmable multi-channel hearing device:
The following parameters can be used as input variables for the fuzzy logic system for determining adaptation parameters:

• Hearing threshold at different frequencies
• Discomfort threshold at different frequencies
• Results of speech intelligibility tests with / without noise
• Subjective hearing impression of the hearing impaired in the sense of better / worse decisions in situations to be compared.

• Trennfrequenzen zwischen den einzelnen Kanälen
• Verstärkung(en)
• AGC-Schwelle(n); Schwelle(n) der automatisch arbeitenden Verstärkungsregelschaltung(en)
• AGC-Kompressionsfaktor(en)
• Peak-Clipping-Schwelle(n) von Begrenzungseinrichtungen
• Filtercharakteristiken (Grenzfrequenz, Flankensteilheit)
• Maximale Verstärkung

Das nachfolgend beschriebene beispielhafte Regelwerk geht davon aus, daß die Unbehaglichkeitsschwelle US und die Hörschwelle HS des Patienten bei verschiedenen Frequenzen ermittelt wurden. (Nomenklatur: "US#1350" steht für Unbehaglichkeitsschwelle bei 1350 Hz)
Der Regelsatz für die Bestimmung der unteren Trennfrequenz UTF könnte dann zB. lauten:

• 1. if (US#1350 - US#350) ist klein then UTF ist ca. 700Hz
• 2. if (US#1350 - US#350) ist groß and (US#1350 - US#700) ist groß then UTF ist größer als 700Hz
• 3. if (US#1350 - US#350) ist groß and (US#1350 - US#700) ist klein then UTF ist kleiner als 700Hz

Der Regelsatz für die Bestimmung der oberen Trennfrequenz (OTF) könnte in analoger Weise angegeben werden mit:

• 1. if (US#2650 - US#1350) ist klein then OTF ist ca. 2000Hz
• 2. if (US#2650 - US#1350) ist groß and (US#2650 - US#2000) ist groß then OTF ist größer als 2000Hz
• 3. if (US#2650 - US#1350) ist groß and (US#2650 - US#2000) ist klein then OTF ist kleiner als 2000Hz.

The following variables, for example, can be considered as output variables of a fuzzy logic system for determining adaptation parameters:

• Crossover frequencies between the individual channels
• Reinforcement (s)
• AGC threshold (s); Threshold (s) of the automatic gain control circuit (s)
• AGC compression factor (s)
• Peak clipping threshold (s) of limiting devices
• Filter characteristics (cut-off frequency, edge steepness)
• Maximum gain

The exemplary set of rules described below assumes that the patient's discomfort threshold US and the hearing threshold HS have been determined at different frequencies. (Nomenclature: "US # 1350" stands for discomfort threshold at 1350 Hz)
The rule set for determining the lower crossover frequency UTF could then, for example. ring:

• 1.if (US # 1350 - US # 350) is small then UTF is about 700Hz
• 2. if (US # 1350 - US # 350) is large and (US # 1350 - US # 700) is large then UTF is larger than 700Hz
• 3. if (US # 1350 - US # 350) is large and (US # 1350 - US # 700) is small then UTF is less than 700Hz

The rule set for determining the upper crossover frequency (OTF) could be specified in an analogous manner with:

• 1.if (US # 2650 - US # 1350) is small then OTF is about 2000Hz
• 2. if (US # 2650 - US # 1350) is large and (US # 2650 - US # 2000) is large then OTF is larger than 2000Hz
• 3. if (US # 2650 - US # 1350) is large and (US # 2650 - US # 2000) is small then OTF is less than 2000Hz.

• 1. if (US#350) ist niedrig then AGCU ist niedrig
• 2. if (US#350) ist groß then AGCU ist hoch

Der Regelsatz für die Bestimmung der Verstärkung im unteren Kanal GU könnte lauten:

• 1. if (HS#350) ist niedrig then GU ist mittel
• 2. if (HS#350) ist hoch then GU ist groß

Eine Möglichkeit des Regelsatzes für die Einstellung der Peak-Clipping-Schwelle PCS lautet:

• 1. if (US#350) or (US#1350) or (US#2650) ist niedrig then PCS ist niedrig
• 2. if (US#350) and (US#1350) and (US#2650) ist hoch then PCS ist hoch.

The rules for determining the AGC threshold in the lower AGCU channel could be defined as follows:

• 1. if (US # 350) is low then AGCU is low
• 2. if (US # 350) is large then AGCU is high

The rule set for determining the gain in the lower channel GU could be:

• 1. if (HS # 350) is low then GU is medium
• 2. if (HS # 350) is high then GU is large

One possibility of the rule set for setting the peak clipping threshold PCS is:

• 1.if (US # 350) or (US # 1350) or (US # 2650) is low then PCS is low
• 2. if (US # 350) and (US # 1350) and (US # 2650) is high then PCS is high.

Claims (6)

Device for adapting programmable hearing aids, comprising a data processing unit (3) which can be coupled to the hearing aid (2) via a signal transmission, into which data (4) characterizing the hearing loss of the hearing aid wearer to be supplied can be entered, and wherein the data processing unit also contains characteristic data (11) of the hearing aid can be supplied or can be called up from a data carrier of the data processing unit, characterized in that the data processing unit (3) has a fuzzy logic module (5), the computing unit (6) of which the inputable and / or retrievable data (4) and characteristic data ( 11) processed using the processing rules from at least one rule base (7) according to the principle of fuzzy logic and provides hearing aid setting data as a result. Device according to claim 1, characterized in that the fuzzy logic module (5) contains at least one data carrier (7), on which processing rules for determining hearing aid setting data - from the data (4) and below characterizing the respective hearing loss of the hearing aid user to be supplied Taking into account the respective hearing aid characteristic data (11) - are stored so that they can be called up. Device according to claim 2, characterized in that a storage means, an EEPROM, a floppy disk or the like is provided as the data carrier (7). Device according to claim 1, characterized in that the data processing unit (3) has a data carrier (9) for the hearing device-specific data (11). Device according to Claims 1 and 2, characterized in that the fuzzy logic module (5) contains an additional data carrier (10) on which processing rules which can be entered by the user of the adaptation device for programming the hearing devices for determining the hearing device setting data can be called up and stored. Device according to one of claims 1 to 5, characterized in that the fuzzy logic module (5) contains, as a computing unit (6), a processor which contains components for fuzzification, inference and defuzzification via an interface (8) and from the data carrier (9) feedable data values (4, 11) using the processing rules of the data carriers (7 or 7 and 10).

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