In situ measurement

This application claims priority of German application No. 10 2007 015 456.0 DE filed Mar. 30, 2007, which is incorporated by reference herein in its entirety.

The present invention relates to in-situ measurement.

In-situ measurement is generally a very complex measurement which is mostly also prone to error and hence produces results which are difficult or even impossible to interpret. This is particularly the case for hearing aids which are open-fitting. The most likely error in in-situ measurement is the use of 2 consecutive measurements (open ear gain and in-situ gain) which are related to one another in order to form a result. The difference between the two measurements gives the insertion gain as the actual measured variable of the in-situ measurement. However, since it is very difficult to ensure that the said two measurements take place under the same conditions, thereby permitting mutual referencing (formation of a difference), the overall result leads to erroneous results. For both the said measurements it is in fact necessary for the in-situ tube to be positioned in the same place in the auditory canal. Otherwise there are different level and phase ratios which prevent the formation of a difference.

As already described in section 1, the in-situ tube is positioned as far as possible in the same place during the OEG and in-situ measurement. However, it (very) frequently happens that when the otoplastic (or the hearing aid, in the case of ITE aids) is inserted the position of the in-situ tube is changed, or the in-situ tube is compressed. As a result, both level and phase ratios change, especially at high frequencies. In hearing aids with open standard ear plugs, the scenario just described occurs even more frequently, since the soft material of the standard ear plugs used, consisting of sound tube and tip (a plug that can be plugged into the sound tube), makes it (almost) impossible to position the in-situ tube identically when performing the OEG and in-situ gain measurement.

FIG. 1 illustrates a hearing aid including an in-situ tube with tip permanently connected; and

FIG. 2 illustrates a hearing aid including an in-situ tube permanently connected to a sound tube.

The sound tube mentioned under section 2 or the tip that can be plugged onto the sound tube is permanently connected to an in-situ tube according to the invention (see FIGS. 1 and 2 in the drawing), so that the exact identical positioning of the in-situ tube is ensured during OEG and in-situ gain measurement. The in-situ tube is thus permanently integrated into the standard ear plug (sound tube and tip). Therefore there is no need to insert the standard ear plug after the OEG measurement to perform the in-situ measurement.

With the invention, the OEG measurement is carried out using the standard ear plug. As a result the position of the in-situ tube for the subsequent in-situ measurement cannot be further changed, which was previously possible and even probable by inserting the standard ear plug after the OEG measurement. Since the tip is as “open” as possible, in the case of a tip (see FIG. 2 ) a measurement of the OEG is likewise involved, although the tip—together with the sound tube—is already in the auditory canal when the in-situ measurement is performed. If in fact comparative OEG measurements are performed, in which the ear is first of all completely open, and in the comparative measurement is closed by an “open tip”, the same result is achieved. Thanks to the inventive action the OEG measurement can thus be measured with the standard ear plug situated in the ear (expanded by the permanently connected in-situ tube). All that is then necessary is to switch the hearing aid on and the in-situ gain can take place with the in-situ tube in exactly the same position. This allows a difference between the two measurements to be formed.

The tube calibration which is customary and necessary for in-situ measurements could be performed as previously with the in-situ tube integrated into the standard ear plug.

After the in-situ measurement has been performed the in-situ tube can be cut off from the rest of the standard ear plug, so that it does not impede the hearing aid wearer in everyday life.

In-situ measurement on hearing aid fittings can be performed more precisely and simply using the invention in the case of an open standard ear plug. The results are “more accurate” thanks to this procedure, since having identical level and phrase ratios makes the formation of a difference more meaningful.