HEARING AID WITH ACOUSTIC GUIDING MEANS

HEARING AID WITH ACOUSTIC GUIDING MEANS

The present invention relates to hearing aids. The invention more particularly relates to a hearing aid comprising at least one microphone for transforming an acoustic signal surrounding a hearing aid user into an electrical signal, signal processing means for processing the electrical signal into an electrical output signal which is supplied to a receiver generating an acoustical signal into the ear canal of a hearing aid user. The hearing aid comprise an ear plug part prepared for being arranged in the ear canal of a hearing aid user.

In the context of the present disclosure, a hearing aid should be understood as a small, microelectronic device designed to be worn behind or in a human ear of a hearing- impaired user. The hearing aid is adjusted by a hearing aid fitter according to a prescription. The prescription is based on a hearing test, resulting in a so-called audiogram, of the performance of the hearing-impaired user's unaided hearing. The prescription is developed to reach a setting where the hearing aid will alleviate a hearing loss by amplifying sound at frequencies in those parts of the audible frequency range where the user suffers a hearing deficit. A hearing aid comprises one or more microphones, a microelectronic circuit comprising a signal processor, and an acoustic output transducer.

A Behind-The-Ear (BTE) hearing aid is worn behind the ear, and has a housing comprising the major electronics parts behind the ear and an earpiece, called ear plug in the following, for emitting sound to the hearing aid user. The ear plug is worn in the ear, e.g. in the concha or the ear canal. In a traditional BTE hearing aid, a sound tube is used for conducting sound from a loudspeaker or receiver in the housing to the ear plug. In some types of hearing aids the receiver is arranged in the ear plug and is connected through electrical conductors to the housing behind the ear. Such hearing aids are commonly referred to as Receiver-In-The-Ear (RITE) hearing aids. Often the receiver is placed inside the ear canal. This may be referred to as Receiver-In-Canal (RIC) hearing aids. In-The-Ear (ITE) hearing aids are designed for arrangement in the ear, normally in the funnel-shaped outer part of the ear canal. Often the hearing aid is placed substantially inside the ear canal. This may be referred to as Completely-In-Canal (CIC) hearing aids. This type of hearing aid requires a very compact design in order to allow it to be arranged in the ear canal, while accommodating the components necessary for operation of the hearing aid, such as microphones, a microelectronic circuit comprising a signal processor, an acoustic output transducer and a battery.

Hearing aids or ear plugs of hearing aids are made to fit tightly in the ear canal of the hearing aid user in order to achieve an optimum sound amplification without risk of feedback. The inner volume is the volume into which the receiver transmits sound in the inner part of the ear canal delimited by the ear plug or hearing aid.

Any need for air ventilation into the inner ear canal is taken care of by a well controlled ventilation channel, often referred to as a vent. A ventilation channel also has the advantage of reducing any occlusion effect (see explanation in WO-A1-2010/083888 page 1 - 3). The ventilation channel usually has a tubular shape, and the diameter is selected as a compromise between the wish to reduce occlusion and the need to obtain a sufficiently high sound pressure level at the ear drum. The ventilation channel (or vent) is an intentional air leak between the volume in front of the ear drum limited by the ear plug or hearing aid, and the surroundings outside the ear canal.

For hearing aid users it may be difficult to arrange the hearing aid or the hearing aid ear plug correct in the ear canal and to verify that it is correctly placed. In the following, the term ear plug is used to refer to the part of the hearing aid to be arranged in the ear canal. The ear plug may be an ear plug of a behind-the-ear hearing aid or an in-the-ear or a completely-in-canal hearing aid. If the ear plug is not correctly placed in the ear canal an unintended air leak between the space in front of the ear drum and the surroundings may be formed. Such an air leak will increase the risk of feedback and it will reduce the sound pressure level produced by the hearing aid at lower frequencies at the ear drum. The benefits of the hearing aid will therefore be reduced. US 2007/0019817 disclose a hearing aid which by playing an acoustic test signal can measure if the fitting of the ear plug is correct. The test signal measured by a microphone is compared to a reference determined beforehand and stored in the hearing aid. If the test signal detected by the microphone deviates from the reference, information is given to an external unit that the fitting is not correct.

WO 2010/049543 discloses a method of measuring feedback of a hearing aid and, based on a comparison with feedback measured when the ear plug is optimally fitted into the ear canal, deciding if the hearing aid is properly inserted in the ear canal of the hearing aid user.

The problem of these known means for controlling the fitting of a ear plug in the ear canal is, that they can only be applied for measuring if the fitting is correct or not. A more intuitively guidance to the hearing aid user during insertion is not provided.

The above problem is solved by a hearing aid that comprises guiding sound generation means for generating an acoustic guiding signal to be provided for a limited period through said receiver during insertion of the ear plug part into the ear canal, in order to be applied by the hearing aid user to optimize the positioning of the ear plug part.

A hearing aid ear plug is here considered as the part of the hearing aid arranged in the ear canal, i.e. it could be the ear plug of a behind-the-ear hearing aid or the whole of a completely-in-canal hearing aid. The advantage of the solution is that it will provide a simple guidance which is intuitively understandable also for new and elderly hearing aid users. The acoustic guiding signal will become louder and change its timbre (or spectral envelope) at the ear drum as the ear plug is moved into the ear canal towards the correct position and weaker as it is moved out of the ear canal away from the correct position. The sound pressure level at the ear drum of the acoustic guiding signal will thus assist the hearing aid user in arranging the sound exit of the ear plug correctly in relation to the ear canal during insertion of the ear plug. Further, the acoustic guiding signal will assist in correct positioning of the ear plug as the sound heard by the hearing aid user will be shaped by the size of air leaks around the ear plug and the size of the air volume between the ear plug and the ear drum. Changes both in the volume (loudness) as well as in the timbre of the acoustic guiding signal, will assist the hearing aid user in the positioning of the ear plug.

In an embodiment of the hearing aid the guiding sound comprises frequencies in a broad range, i.e. frequencies below 500 Hz and frequencies above 1000 Hz. Here, especially the medium frequency part in the range 1 - 2 kHz will assist the hearing aid user in moving the ear plug from outside the ear into the ear canal towards the correct position. The lower frequencies will subsequently assist the user in detecting if the ear plug is correctly placed inside the ear canal in relation to possible ear leaks, intentional as well as non- intentional air leaks. In an embodiment of the hearing aid the acoustic guiding signal is provided for a given period after the power to the hearing aid is turned on. Then the hearing aid user does not need to do anything to turn off the signal. The time period for which the signal is turned on may be adjustable to the needs of the individual user. In a further embodiment the hearing aid comprises a wireless connection with an external device, such as a remote control, wherein a signal from said external device can initiate the acoustic guiding signal if this is needed at other times than when the hearing aid power is turned on. In an embodiment of the hearing aid the acoustic guiding signal is made up of a number of short signals with intervening pauses in the signal.

In a further embodiment of the hearing aid the ear plug is provided with a further microphone for measuring the sound pressure level in the volume between the ear plug and the ear drum, and, by application of this measuring of the sound pressure level, the hearing aid is adapted for detecting if the ear plug is correctly fitted. In this way it will be possible to provide information of changes in the effective size of the air leak, such that the hearing aid user will know if a given change is improving the fit of the hearing aid ear plug. This will guide the user to optimize the placement of the hearing aid by providing feedback on the effect of a given change. Another embodiment is directed to a method for guiding a hearing aid user in the insertion of an ear plug in order to obtain a correct positioning of the ear plug in the ear canal, and the hearing aid comprises at least one microphone for transforming an acoustic signal surrounding a hearing aid user into an electrical signal. The hearing aid comprise signal processing means for processing the electrical signal into an electrical output signal which is supplied to a receiver generating an acoustical signal into the ear canal of a hearing aid user. The method further comprises arranging an ear plug part in the ear canal of the hearing aid user, and generating an acoustic guiding signal for a limited period through the receiver during insertion of the ear plug part into the ear canal, in order to be applied by the hearing aid user to optimize the positioning of the ear plug part.

An embodiment of this method comprises selecting the frequency range and sound pressure level of the guiding sound or the acoustic guiding signal according to the specific hearing loss of the hearing aid user. Thereby, it will be possible for the hearing aid user to hear the guiding sound also when the ear plug is outside the ear canal, and the guiding sound can be adjusted such that the sound pressure level will not be too high when the ear plug is inserted into the ear canal.

Some embodiments will now be explained in further detail with reference to the figures.

Figure 1 illustrates an in-the-canal hearing aid.

Figure 2 illustrates a block diagram of a method for arranging an ear plug of a hearing aid in the ear canal. Figure 1 shows a completely- in-the-canal hearing aid 1 arranged in the ear canal 11 of a hearing aid user. The hearing aid 1 comprises a receiver 2 for generating an acoustic output in front of the ear drum 10, and an opening 4 for a microphone arranged in order to detect acoustic signals from outside the ear of the hearing aid user, i.e. from the surroundings. The hearing aid 1 further comprises a ventilation channel 5, i.e. an intentional air leak, e.g. for the purpose of reducing occlusion.

The hearing aid of figure 1 could also have been an in-the-ear hearing aid which is partly in the canal and partly in the concha. It could also have been a behind-the-ear hearing aid with an ear plug. Often the receiver is arranged in the ear plug part as illustrated in figure 1. But in the case of a behind-the-ear hearing aid the receiver may also be arranged in the behind-the-ear part and the sound guided to the ear plug part through a sound tube. The ventilation channel 5 is an option which is often preferred due to its advantages, e.g. in relation to occlusion. However, if a high gain is necessary due to a profound hearing loss, a ventilation channel may be avoided since a higher sound pressure at the eardrum can be obtained without the ventilation channel. A ventilation channel 5 may have different forms or shapes.

A well defined acoustic guiding signal provided by the receiver 2 can be applied for guidance of the hearing aid user during insertion of the ear plug. This could be by providing a well defined sound in a broad frequency spectrum during a limited period when the ear plug is inserted into the ear canal. Such a sound would become familiar to the hearing aid user who would learn to position the ear plug in the ear canal by relying on changes in the sound.

The acoustic guiding signal will be louder the closer the ear plug gets to the ear drum. I.e. the sound pressure level will be higher. Further, the frequency of the acoustic guiding signal will be shaped by the size of air leaks around the ear plug and by the size of the air volume between the ear plug and the ear drum. The acoustic guiding signal will thus assist the hearing aid user in arranging the sound exit of the ear plug correctly in relation to the ear canal during insertion of the ear plug. After a little practice with insertion of the ear plug while hearing this acoustic guiding signal the hearing aid user will learn how the volume and timbre of the acoustic guiding signal should be when the ear plug is correctly positioned in the ear canal. The hearing aid user will also become familiar with the gradual change during insertion of the sound of the acoustic guiding signal leading to a correct placement of the ear plug.

The acoustic guiding signal could be generated on an integrated circuit e.g. the integrated circuit also comprising the signal processing means. A generator of the acoustic guiding signal may be included on this circuit.

Figure 2 shows a block diagram of an embodiment of a method according to the invention. The first step 20 is to turn on the power to the hearing aid. The next step in figure 2 is to generate a guiding sound by the receiver. This guiding sound is applied as the acoustic guiding signal.

The hearing aid may be set up to initiate the acoustic guiding signal when the power is turned on, e.g. with a short delay of a few seconds e.g. 1 - 3 seconds. The duration of the acoustic guiding signal should be such that the hearing aid user has sufficient time to arrange the ear plug in the ear canal. This could be in the range 10 - 25 seconds, but preferably this time is adjustable during the fitting of the hearing aid. During hearing aid fitting it should also be possible to select whether the acoustic guiding signal should be applied or not. The generated guiding sound or the acoustic guiding signal may be within a given frequency range. The acoustic guiding signal typically has a relatively broad frequency distribution covering both the 200 - 1000 Hz range as well as the 1 - 2 kHz range. Preferably, the frequency range below 500 Hz and the range above 1000 Hz are covered. The acoustic guiding signal may be provided as a continuous sound or it may be modulated e.g. to a series of short "beep" or "doing" sounds or even transient sounds like clicks. The third step 22 in figure 2 is to insert the ear plug into the ear canal. The fourth step 23 is to move the ear plug until the guiding sound or the acoustic guiding signal becomes familiar. The familiar sound could be learned by the hearing aid user during fitting of the hearing aid, where the hearing aid fitter places the ear plug in the correct position and the acoustic guiding signal is played.

The fifth step 24 is that the guiding sound or acoustic guiding signal is stopped. As mentioned this may happen after a preset time, but the signal could also be stopped by the hearing aid user, e.g. by a remote controlling device.

It may also be possible to initiate the acoustic guiding signal by the hearing aid user without having to switch power to the hearing aid off and on again. This could be done by a switch on the hearing aid, or it could be done by a signal from a remote control or from another unit wirelessly connected to the hearing aid.

It should be possible to switch off the means for initiating the acoustic guiding signal when turning on power to the hearing aid. This will often be relevant when the hearing aid user has learned to arrange the ear plug correctly without the need for the acoustic guiding signal. Switching off these means may be performed by the hearing aid fitter.