Method for adjusting a hearing aid with high-frequency amplification

Abstract

It should be possible to quickly and effectively adjust a hearing aid even in the high-frequency range above 8 kHz. For this purpose it is provided that an open-loop gain measurement is carried out in the upper frequency range and a maximum amplification or a frequency-dependent maximum amplification curve is fixed. This maximum amplification in the high-frequency range should not be exceeded. The hearing aid wearer can then optionally select one of a plurality of amplification curves located there below. In the low-frequency range a conventional amplification adjustment is carried out for example by a prescriptive audiogram-based formula. A hybrid adjustment procedure that is easy to carry out is thereby provided for the entire frequency range.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will now be described in more detail with reference to the accompanying drawings, in which:

FIG. 1 shows a flow diagram for carrying out a method according to the invention for the adjustment or setting of a hearing aid and

FIG. 2 shows smoothing of amplification curves at the boundary between lower and upper frequency ranges.

DETAILED DESCRIPTION OF THE INVENTION

The following exemplary embodiments described in more detail constitute preferred embodiments of the present invention.

According to FIG. 1 conventional amplification adjustment takes place first of all in the lower frequency range or in the base frequency range [0-fb] according to steps S1 and S2. For this purpose loudness impressions are recorded by a hearing aid wearer in step S1, so an amplification adjustment can be carried out on the basis of the subjectively perceived loudness. Alternatively an audiogram of the patient is taken, so the hearing threshold thereof is known.

According to step S2 the amplifications or amplification curves which are to be implemented in the hearing aid are calculated from the loudness scaling or the audiogram. For this purpose prescriptive adaptation formulae are used which, for example, are known by the names NAL-NL1, DSL-I/O. Company-specific formulae as well as a loudness normalization may also be used for the amplification calculation. Ultimately an amplification curve or a family of amplification curves is obtained for the lower frequency range [0-fb Hz]. The base limit frequency fb lies, for example, at 6 kHz.

For the upper frequency range [fb-fg Hz] where fg is for example 12 kHz, what is known as an open-loop gain measurement (OLG measurement) is now carried out according to step S3. This OLG measurement can also be extended to the lower frequency range. For the OLG measurement the signal path of the hearing aid is interrupted for example, test sounds of various frequencies are digitally generated in the hearing aid, output via the hearing aid earpiece and the digital level of the signal again received by the hearing aid microphone(s) determined upstream of the interruption point. The difference from the original digital level of the test stimulus is the open-loop gain (OLG) with the aid of which the maximum possible amplification without feedback whistling (feedback limit) may be quantified. This determination of the maximum amplification corresponding to step S4 takes place for each frequency or each desired frequency band in the high frequency range [fb-fg]. A certain spacing [feedback reserve, preferably 6-12 dB] is advantageously maintained from the feedback limit to avoid feedback whistling even in the event of slight changes in the feedback path in everyday life.

The reduction in feedback susceptibility is optionally reduced by notch filters or other narrow band filters. Alternatively or additionally feedback reductive algorithms, such as oscillation detection and adaptive notch filters or feedback compensators, can be used. In each case the amplification range may be expanded hereby.

While taking account of the feedback limit (maximum amplification) and the feedback reserve a plurality of optional amplification curves are determined in step S5. For example the amplification curves consist of the maximum possible amplification in the upper frequency range Gmax (f) and reduced amplifications, derived therefrom, in the desired number. Percentage reduced curves for example, such as 75% Gmax (f), 50% Gmax (f), etc., may thus be provided. The amplification in the high-frequency range can be exactly adjusted using a plurality of bands, in particular by using a filter bank. Explicitly no prescriptive or loudness-based adjustment methods are therefore used in the high-frequency range.

The amplification curves from the low-frequency and high-frequency ranges would, as a rule, merge discontinuously. Smoothing of the discontinuous transition of the amplification stages is therefore carried out from the base frequency range to the high frequency range at f=fb according to step S6. Smoothing takes place for example by weighted addition within a frequency band [f1-f2], where f1<fb and f2>fb. In a specific example the following could apply: fb=6 kHz, f1=4 kHz and f2=8 kHz. A continuous amplification curve is therefore obtained for all amplification curves in the entire frequency range [0-fg].

In step S7 the hearing aid wearer chooses a variant that is suited to him or her from the whole family of amplification curves. For this purpose he is presented with sound examples or he can make the selection using the everyday acoustic environment. In both cases hearing situations, such as music, speech or the like, can be used (cf. step S8).

If the hearing aid wearer comes to the conclusion that the amplification in the high-frequency range is not suited to him or her, the amplification in the high-frequency range is varied according to step S5. The amplification curves of high-frequency and low-frequency ranges are subsequently smoothed again in step S6 and the hearing aid wearer can then evaluate the newly obtained amplification curve again in step S7.

If, finally, an amplification curve is okay for the hearing aid wearer this amplification curve is permanently implemented in the hearing aid. However, following selection of the amplification curve another automatic amplification increase may optionally also take place with time. The hearing aid wearer may thus gradually adjust, i.e. acclimatize, to the new hearing impression.

The above-mentioned smoothing or adjustment of the amplification curves in the high-frequency range and the low-frequency range can be described in more detail with reference to FIG. 2. Firstly the amplification target curve 1 for quiet levels, the amplification target curve 2 for medium levels and the amplification target curve 3 for loud levels are obtained by prescriptive adjustment, for example by the formula NAL-NL1. These amplification target curves are used in the lower frequency range up to 4 kHz (cf. steps S1 and S2). An OLG measurement is also performed over the entire frequency range and a maximum amplification 4 established by taking account of a feedback reserve (cf. steps S3 and S4).

In the higher frequency range from about 6 kHz the amplification is fixed according to a different adjustment method. For example the high-frequency fractions should be constantly amplified according to curve 5. Since the maximum amplification curve 4 intersects with the target curve 1 at about 4 kHz and with the amplification curve 5 at about 8 kHz, amplification for loud levels is limited to the maximum amplification in the range between 4 and 8 kHz. For medium and quiet levels interpolations are carried out in the range between 4 and 6 kHz which connect the amplification curve 5 or the maximum amplification curve 4 at about 6 kHz to the target amplification curve 2 or the target amplification curve 3 at 4 kHz. This results in the interpolation sections 6 and 7. A smooth transition from the respective amplification curve 1, 23 in the low-frequency range to the amplification curve 5 in the high-frequency range may thus be ensured.

Amplification in the high-frequency range can be varied according to arrow 8. An amplification curve 9 in the high-frequency range can, for example, equally be selected thereby. In this case this curve 9 is not obtained by division of the maximum amplification curve 4 by a constant factor according to the above-mentioned example either, rather the example of FIG. 2 is intended to show that the amplification curves in the high-frequency range can also be obtained by methods other than by constant division. Interpolation transitions to the target amplification curves 1 to 3 are also used for the amplification curve 9 in the frequency range between 4 kHz and 6 kHz.

Claims

1.-6. (canceled)

7. A method for adjusting an amplification of a hearing aid, comprising: adjusting the amplification of the hearing aid in a lower frequency rang;performing an open-loop gain measurement in an upper frequency range adjoining the lower frequency range;determining a frequency dependent maximum amplification curve in the upper frequency range using the open-loop gain measurement; andadjusting the amplification of the hearing aid in the upper frequency range using the maximum amplification curve.

8. The method as claimed in claim 7, wherein the amplification of the hearing aid in the lower frequency range is prescriptively adjusted or adjusted based on a loudness impression of a wearer of the hearing aid.

9. The method as claimed in claim 7, wherein feedback susceptibility of the hearing aid is reduced by a narrow band filter or a feedback reduction algorithm.

10. The method as claimed in claim 7, wherein an amplification curve below the maximum amplification curve is calculated in the upper frequency range and is merged to an amplification curve in the lower frequency range.

11. The method as claimed in claim 7, wherein a plurality of amplification curves below the maximum amplification curve are calculated in the upper frequency range.

12. The method as claimed in claim 11, wherein one of the amplification curves is selected and merged to an amplification curve in the lower frequency range.

13. The method as claimed in claim 12, wherein a wearer of the hearing aid is exposed to a sound and interactively selects the one amplification curve.

14. The method as claimed in claim 7, wherein the amplification of the hearing aid in the lower or upper frequency range is automatically increased with time.

15. The method as claimed in claim 7, wherein a maximum amplification is determined in the upper frequency range using the open-loop gain measurement.

16. The method as claimed in claim 7, wherein the upper frequency range is above 6 kHz or 8 kHz.

17. A hearing aid to be worn by a hearing aid wearer, comprising: a first processing unit that adjusts an amplification of the hearing aid in a lower frequency range;a measurement unit that performs an open-loop gain measurement in an upper frequency range adjoining the lower frequency range; anda second processing unit that determines a frequency dependent maximum amplification curve in the upper frequency range using the open-loop gain measurement.

18. The hearing aid as claimed in the claim 17, wherein the amplification of the hearing aid in the lower frequency range is prescriptively adjusted or adjusted based on a loudness impression of the hearing aid wearer.

19. The hearing aid as claimed in the claim 17, wherein feedback susceptibility of the hearing aid is reduced by a narrow band filter or a feedback reduction algorithm.

20. The hearing aid as claimed in the claim 17, wherein an amplification curve below the maximum amplification curve is calculated in the upper frequency range and is merged to an amplification curve in the lower frequency range.

21. The hearing aid as claimed in the claim 17, wherein a plurality of amplification curves below the maximum amplification curve are calculated in the upper frequency range.

22. The hearing aid as claimed in the claim 21, wherein one of the amplification curves is selected and merged to an amplification curve in the lower frequency range.

23. The hearing aid as claimed in the claim 22, wherein the hearing aid wearer is exposed to a sound and interactively selects the one amplification curve.

24. The hearing aid as claimed in the claim 17, wherein the amplification of the hearing aid in the lower or upper frequency range is automatically increased with time.

25. The hearing aid as claimed in the claim 17, wherein a maximum amplification is determined in the upper frequency range using the open-loop gain measurement.

26. The hearing aid as claimed in the claim 17, wherein the upper frequency range is above 6 kHz or 8 kHz.