a2 United States Patent
`US 6,741,712 B2
`(0) Patent No.:
`*May 25, 2004
`Bisgaard
`(45) Date of Patent:
`
`US006741712B2
`
`(54) TIME-CONTROLLED HEARING AID
`
`(56)
`
`References Cited
`U.S. PATENT DOCUMENTS
`
`(75)
`
`Inventor: Nikolai Bisgaard, Lyngby (DK)
`
`(73) Assignee: GN ReSoundA/S, Taastrup (DK)
`
`(*) Notice:
`
`Subject to any disclaimer, the term of this
`patent is extended or adjusted under 35
`U.S.C. 154(b) by 174 days.
`
`This patent is subject to a terminal dis-
`claimer.
`
`(21) Appl. No.: 09/886,329
`
`(22)
`
`(65)
`
`Filed:
`
`Jun. 21, 2001
`
`Prior Publication Data
`US 2001/0055404 Al Dec. 27, 2001
`
`Related U.S. Application Data
`
`(63) Continuation of application No. PCT/DK99/00687,filed on
`Dec. 8, 1999.
`
`(30)
`
`Foreign Application Priority Data
`
`Jant.8,1999.
`
`(DB) seemescen ees eer aevecreneess 1999 00017
`
`(SL)
`
`Tint, C1. ieee ceeccccceeceeeeeeeteaneseneseenneene HO04R 25/00
`
`(62) US. Che: creer sseesceeseeeeer err: 381/312; 381/315
`
`(58) Field of Search 0.0.00. 381/60, 312, 314,
`381/315, 316, 320, 323, 328, 331; 600/559
`
`4,049,930 A *
`9/1977 Fletcher ct al. oe. 381/60
`
`4,777,474 A * 10/1988 Clayton oo... 381/312
`4/1989 GTOOMS oo. eeeeeeees 368/63
`4,821,247 A *
`4,972,487 A
`11/1990 Mangoldetal.
`5,210,803 A
`5/1993 Martin et al.
`6,008,720 A * 12/1999 Honguetal. ......... 340/309.15
`
`* cited by examiner
`
`Primary Examiner—Suhan Ni
`(74) Attorney, Agent, or Firm—Bingham McCutchen LLP;
`David G. Beck
`
`(57)
`
`ABSTRACT
`
`A hearing aid which comprises a sound transducer, an
`analogue-digital converter, a digital processing and adapta-
`tion circuit for the processing of digital signals, correspond-
`ing to audio signals which are received by the transducer,
`storage units for the storage of data and programmesfor the
`digital processing and adaptation circuit, a digital-analogue
`converter and a sound generator. The hearing aid also
`contains a counter, which registers the time for which the
`hearing aid has beenin use, and a non-volatile storage unit
`in which the utilisation time is summedup. ‘The hearing aid
`is arranged in such a manner that a comparison is made
`between the contents of that part of the non-volatile storage
`unit in which the summed-up utilisation time is stored and
`one or more limit values, and so that when one or more of
`the limit values is reached, a special function is initiated.
`
`10 Claims, 2 Drawing Sheets
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`HIMPP 1006
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`INTERFACE
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`HIMPP 1006
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`

`

`U.S. Patent
`
`May 25, 2004
`
`Sheet 1 of 2
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`US 6,741,712 B2
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`WOeaw
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`“WvsoOud
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`JOVAYILNI
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`|‘Bly
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`

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`U.S. Patent
`
`May 25, 2004
`
`Sheet 2 of 2
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`US 6,741,712 B2
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`

`1
`TIME-CONTROLLED HEARING AID
`
`US 6,741,712 B2
`
`2
`The total time for which the hearing aid is used will
`hereby be registered currently in the hearing aid, and when
`one or more limit values are exceeded,in that a limit value
`can be set e.g. for a subscription period, said limit values
`having been previously stored in the hearing aid, a special
`function will be initiated which indicates to the userthat the
`
`subscription period has expired or is nearing expiry. The
`user can hereatter take the steps necessary for extending the
`subscription.
`it can be expedient for the
`As disclosed in claim 2,
`special function which is initiated to consist of a deactiva-
`tion of the hearing aid, in that e.g. when the limit value is
`execeded, a disconnection of the hearing aid battery or other
`vital functions in the aid can be effected.
`
`the special function can
`As characterized in claim 3,
`consist of an alarm arrangement, whereby in the event of a
`first limit value being exceeded, the user is made aware that
`the subscription period has expired or is nearing expiry, e.g.
`by the hearing aid emitting a short acoustic signal which is
`possibly repeated. If the subscription is not renewed,this can
`be combined with the deactivation of the hearing aid after a
`second limit value is exceeded.
`
`Finally, as disclosed in claim 4, the exceeding of a limit
`value can initiate a changing of the parameters and/or
`programmes which have influence on the operation of the
`hearing aid, so that an updating of the functionofthe hearing
`aid can take place automatically after a certain period of
`time, either in connection with the expiration of a subscrip-
`tion period or at a random time determined by the dealer or
`the audiologist.
`The renewal of the subscription can naturally take place
`by the user paying a visit to the dealer (audiologist), who
`will update the hearing aid by means of the PC equipment,
`which is normally used when the hearing aid is set for use.
`As disclosed in claim 5, it can be-expedient for this to be
`carried out when the hearing aid is arranged to detect special
`reactivation signals. The detection of such reactivation
`signals, which e.g. can be, coded signals, results in the
`updating of the hearing aid.
`As disclosed in claim 6, this updating can, for example,
`consist of the counter for the summed-up utilisation time
`being set to zero, so that a new subscription period can be
`started, or as disclosed in claim 7, that the stored limit value
`or values are increased corresponding to a new subscription
`period. With the latter method,
`the further advantage is
`achieved that the time counter will thus always contain a
`measure of the total utilisation time.
`
`Morcover, with the updating, it can be expedient for
`further changes to be made in the data and/or the pro-
`grammeswhichare stored in the hearing aid,as disclosed in
`claim 8, whereby an automatic updating of the function of
`the hearing aid is effected. For example, this can be the case
`in connection with new users, where use is made of a
`habituation system. With such a habituation system, there
`will occur a gradual transition from no hearing aid to full
`compensation for the user’s loss of hearing.
`For the user, however, it will be an inconvenience to have
`to visit the dealer/audiologist to have the hearing aid updated
`by means of the PC equipment, which the dealer uses for
`adjustment of the hearing aid.
`As disclosed in claim 9, the hearing aid can therefore be
`supplied with reactivation signals by special audio signals
`being sent to the hearing aid’s microphone. For example,
`this can be effected by the user telephoning to the dealer/
`audiologist, or vice-versa, (for example when the subscrip-
`tion fee for the following period has been paid), andthat the
`audiologist then transfers the code signals via the telephone
`
`This application is a continuation of international appli-
`cation Ser. No. Pct/OR99/00687filed Dec. 8, 1999.
`The invention concerns a hearing aid of the kind which
`comprises a soundtransducer, an analogue-digital converter,
`a digital processing and adjustmentcircuit for the processing
`of digital signals, corresponding to audio signals which are
`received bythe transducer, memory units for the storage of
`data and programmesfor the digital processing and adjust-
`mentcircuit, a digital-analogue converter and a speaker.
`A hearing aid of this known kind is described for
`cxample in the U.S. Pat. No. 4,972,487, which concerms a
`programmable hearing aid which also contains data logging
`means. With this data logger it can be registered how many
`times each programmeis activated, and for how long each
`programmeis used. By the reading out of the data registered,
`an audiologist or a fitter or the like can ascertain for how
`long and how manytimesthe individual user of the hearing
`aid has used the individual programmes over an elapsed :
`period of time.
`Known hearing aids of this kind are normally sold to the
`user as a one-time service at a relatively high purchase price.
`In addition to the hearing aid itself, this purchase price also
`covers an obligation, which the hearing aid dealer
`undertakes, to provide the user with service with regard to
`subsequent adjustment, advice, maintenance etc. for a sub-
`sequent period. which is normally of 3—5 years. All repairs
`are covered by a guarantee of 1-2 years, which thereafter are
`paid for by the user, but these repairs can, however, be
`covered if extra insurance is taken out.
`For several various reasons, it would be desirable if the
`hearing aids could be sold in connection with subscription
`arrangements in the same wayas e.g. is knownin connection
`with contact lenses, where a start fee is paid upon estab-
`lishing a subscription agreement, after which regular sub-
`scription fees are paid which cover, e.g. an annual check-up
`of the eyesight and continuous deliveries of newlenses.
`For the hearing aid dealer, such an arrangement would
`have the advantage that this would provide a continuous
`income. For the users of the hearing aids, the advantage
`would be that the relatively high one-time service price upon
`acquiring the hearing aid would be spread over a series of
`years, and the users will also have the advantage that
`providing the regular subscription fee is paid, they will be
`ensured that repairs, service etc. of the hearing aid will be
`carried out and moreover, that they will be able to have their
`hearing checked regularly in connection with the subscrip-
`tion.
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`10
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`15
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`However, such a subscription arrangement in connection
`with hearing aids requires that it is possible to stop the
`current services if the user does not pay the subscription
`fees, in the same wayas the regular deliveries of new contact
`lenses can be stopped in connection with lens subscribers.
`This is achieved in a hearing aid of the kind disclosed in
`the introduction which contains a counter element for the
`registration of the utilisation time and a storage unit for the
`storage of this data, and whichis characteristic in that the
`counter element comprises a counter for the registration of
`the time the hearing aid has been used, that the storage unit
`for the storage of this data comprises a non-volatile memory
`in which the utilisation time is summed up, that the hearing
`aid is arranged in such a manner that a comparison is made
`between the contents of that part of the non-volatile memory
`in which the summed-up utilisation time is stored and one or
`more limit values, and that when one or more of the limit
`values is reached, a special function is initiated.
`
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`US 6,741,712 B2
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`3
`connection white the user holds the hearing aid close to the
`telephone receiver. The updating can hereby be effected
`quickly without
`the user having to visit
`the dealer/
`audiologist.
`Other methods by which audio signals can be transferred
`to the hearing aid can be envisaged. For example,
`the
`dealer/audiologist can send a postcard with an audio chip or
`a tape on which the coded audio signals have been recorded,
`or use can be madeofthe Internet to transfer audio signals
`to the user’s hearing aid. After a subscription fee has been
`paid, the user can thus get the coded signals transferred by
`calling an Internet address from a PC. The payment of the
`subscription fee can also possibly be made overthe Internet,
`so that with a single call the user cannot only make the
`paymentbut also get the coded signals transferred to the
`hearing aid.
`In connection with the use of coded audio signals as
`reactivation signals, use can be made, for example, of the
`DTMEFsignals (Dual Tone Multi-Frequency), for example
`well known from the telephone systems, where two simul-
`taneous pure tones are used to signal a digit between 0 and :
`9. Such signals are relatively easy to detect in the hearing
`aid’s digital signal processing circuit, and at the same time
`an ordinary telephone keypad can be used as coding appa-
`ratus.
`
`10
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`15
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`Finally, as disclosed in claim 10, the hearing aid can be 2
`arranged with a number of code keys, pushbuttons or the
`like, so that the reactivation signals can be entered by the
`user. This has the advantage that the code can be sent to the
`user in writing, expressed as the entries, which must be
`made, after which the user himself can key in the code at a
`convenient time.
`
`In both cases it will be an advantage that the code is
`changed from timeto time, so that the user cannot just copy
`a code from a previoussubscription period,e.g. by recording
`the coded audio signals on tape, and use this for the
`subsequent subscription period(s).
`In the following, the invention will be explained in more
`detail with reference to the drawing, where
`FIG. 1 shows a block diagram of a digital hearing aid
`according to the invention, and
`FIG. 2 shows an example of a signal-processing block in
`a digital hearing aid according to the invention.
`An example of a digital hearing aid according to the
`invention is shown in block diagram form in FIG. 1. The
`hearing aid, which is indicated in general by the reference
`FIG. 1, contains one or more sound transducers 2 such as
`microphonesand tele-coils. In the example shown, use is
`thus made of two microphones 2a and a tele-coil 2b. The
`analogue signal(s) from the sound transducers 2a and 2b are
`coupled to an analogue-digital conversion circuit 3, which
`contains an analogue-digital converter 4 for each of the
`transducers 2@ and 2b.
`
`The digital signal outputs from the analogue-digital
`converters 4 are coupled to a commondigital conduction bus
`5, which feeds the signals to a digital signal processing and
`adaptation circuit 6. This circuit which, for example, can be
`in the form of a digital signal processor (DSP), and which
`will be described in more detail later, is programmed to carry
`out the necessary operations on the digital signals with the
`object of effecting the necessary adaptation of the signals
`and to adjust the hearing aid for the actual user.
`From the digital conduction bus 5, output signals are fed
`to a digital-analogue converter 12, from which analogue
`output signals are fed to a sound transducer 13 such as a
`speaker.
`the hearing aid contains an external
`Furthermore,
`memory 14 in relation to the digital signal processing and
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`4
`adaptation circuit 6, which in the example shown is an
`EEPROM (Electronically Erasable Programmable Read-
`Only Memory). This external memory 14, which is con-
`nected to the digital conduction bus 5, can be provided with
`programmes,data, parameters etc. that can be entered from
`a PC 16 via an interface 15. For example, this will be the
`case whena new hearing aid is allotted to a concrete user,
`and the hearing aid is adjusted to suit precisely this user, or
`whena usergets his/her hearing aid updated and/or adjusted
`by an audiologist for the user’s actual loss of hearing.
`The digital signal processing and adaptation circuit 6,
`which in the example shown consists of a digital signal
`processor (DSP), contains a central processor (CPU) 7 and
`a numberof internal storage units 8-11, said internal storage
`units containing data and software which are currently
`implemented in the digital signal processing and adaptation
`circuit 6. The circuit 6 thus contains a programme-ROM
`(Read-Only Memory) 8, a data-ROM 9, a programme-RAM
`(Random Access Memory) 10 and a data-RAM 11. The two
`first-mentioned contain programmes and data which consti-
`tute permanent elements in the circuit, while the two last-
`mentioned contain programmes and data which can be
`replaced or overwritten.
`The external EEPROM 14 is normally considerably
`larger, e.g. 4-8 timeslarger, than the internal RAM, which
`meansthat certain data and programmescan be stored in the
`EEPROMfor reading into the internal RAMsfor execution
`when there is need for them, in that these special data and
`programmes can later again be overwritten by the normal
`operational data and operating programmes. The external
`EEPROMcan thus contain a numberof programmes, which
`are used only in special cases, such as e.g. start-up pro-
`grammes.
`In the digital signal processing and adaptation circuit 6,
`the signal processing will be effected in blocks, each of
`which contains a number of signal processing stages and
`data operations. These stages will be executed one by one
`and will be repeated in the individual blocks in the same
`pattern in fixed time frames. This is illustrated in FIG. 2,
`which showsa single signal-processing block in a temporal
`sequence, which sequence is repeated during the whole of
`the hearing aid’s operating period.
`‘The signal processing starts by a Fourier transformation
`of the signals from the time domainto the frequency domain
`being carried out on the sampled digital signals from the
`analogue-digital conversion circuit 3. In the example, use is
`madeof a Fast-Fourier-Transformation (FFT), as illustrated
`at the stage 20. Hereafter, a compression (COMP)is typi-
`cally carried outas illustrated at stage 21, with the object of
`bringing the signals within a desirable processing range. The
`object of this compression is to adapt the signal to the actual
`user, in that those frequencies at which the user has a loss of
`hearing will be raised in relation to the remaining frequen-
`cies in such proportion that the hearing loss will be neutra-
`lised. There is then effected a filtration by means of an
`adaptivefilter (DFS) at stage 22, the object being to suppress
`a possible tendency towards acoustic feedback. Moreover,
`other types of desirable signal processing will be able to be
`effected before the last stage 26 in the block, where an
`inverse Fast-Fourier-Transformation (IFFT) of the signals
`back to the time domain is carried out. As shown in FIG. 1,
`these signals will be fed to the digital-analogue converter 12,
`after which the corresponding analogue signals are fed to the
`speaker 13.
`The block described above consisting of a group of
`stages will, for example, have a temporal sequence which
`extends over 4 ms, so that the block will be repeated every
`
`

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`5
`4 ms. If, for example, the sampling frequency is 16 kHz,
`during the course of 4 msthere will be collected 128 samples
`which are stored in the data-RAM 11. The block oriented
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`US 6,741,712 B2
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`6
`by the supply of audio signals to the microphones 2, or by
`signals which are generated by means of a code keypad in
`the hearing aid being introducedinto the hearing aid’s signal
`circuit. Finally, the reactivation signals can naturally be fed
`directly to the hearing aid, e.g. by an audiologist using a PC
`16 and an interface 15, such as shown in FIG. 1. However,
`this naturally requires that the hearing aid user visits the
`audiologist with his/her hearing aid, or gives the audiologist
`access to the aid in another manner.
`
`If this involves audio signals whichare transferred to the
`hearing aid’s microphones,this can be carried out e.g. over
`a normal telephoneline, in that the hearing aid user can hold
`the hearing aid up against the telephone handsct, so that the
`microphones in the hearing aid can receive the sound from
`the telephone receiver. The coded signals can also be trans-
`ferred to the hearing aid user in other ways, e.g. in the form
`of tape recordings or audio chips with the desired code
`sequence which can be sent to the user as ordinary mail.
`The audio signals can also be transferred to the user’s
`hearing aid via the Internet, in that after the subscription fee
`has been paid, the user can call an Internet address from
`his/her PC and have the code signals transferred. The
`paymentof the subscription fee can possibly also take place
`over the Internet, so that both the payment and the transfer
`of the coded signals to the hearing aid can be effected with
`a single call by the user.
`If a code keypadis used on the hearing aid, in its simplest
`form this can consist solely of two keys with which the
`hearing aid users can enter a code sequence, which has been
`sent to them. More than two keyscan, of course, be used for
`the entering of code sequences, such as e.g. a telephone
`keypad of the kind normally used.
`In the fitting of a user with a hearing aid, the dealer/
`audiologist will have provided the hearing aid with the
`programmes and the data, which are necessary for its
`operation. There will thus be entered the programmes and
`data which control the signal adjustment with the view to
`compensating for the user’s hearing loss for at least a first
`period. Moreover, among otherthings,at least the maximum
`utilisation time for the first subscription period will be
`entered and,
`if a habituation system is used where the
`compensation is to be gradually increased, the data and/or
`the programmes, whichare to be used in the signal process-
`ing for at least the following period.
`When the hearing aid is switched on by the user and
`taken into use, thefirst thing to be entered from the external
`EEPROM 14 will be a start-up programme which, among
`other things, checks whether the summed-up utilisation time
`(stored in the “hour counter” storage unit), has exceeded one
`or more of the stored limit values forthe utilisation time. If
`this is the case, this will result in the initiation of a special
`programme which,if a subscription period has expiredoris
`about to expire, can e.g. execute an alarm or signalling
`function,e.g. in the form of a series of audio signals, and/or
`which can deactivate the hearing aid e.g. by breaking the
`connection to the speaker, after which the normal operating
`programme will not be initiated.
`If none of the stored limit values have been exceeded, an
`operating programme will
`read in from the external
`EEPROM, after which the hearing aid will function in the
`normal manner.
`
`In the updating of the hearing aid, i.e. when the hearing
`aid detects a series of reactivation signals, a special pro-
`grammewill be initiated in the digital circuit which checks
`whether the coded signal is that which is expected (ie.
`corresponding to a code which is stored in the EEPROM),
`and in such case among other things an updating of the
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`signal processing will thus be carried out on such a group of
`128 samples,starting with a Fast-Fourier-Transformation in
`stage 20.
`In addition to the already described examples of types of
`signal processing, the block in FIG. 2 will further comprise
`three system operations or programmes, which are repeated
`every fourth millisecond.
`The object of the programme 23 (Reg. Time) is to
`register the utilisation time for the hearing aid, and it
`functions by usc of two storage units “counter” and “hour
`counter”) in data-7RAM 11. When the programme 23 is
`executed,
`it will read the contents of the storage unit
`“counter” and increase the value by 1. With a run-through
`time for a block of 4 ms, an hour will have elapsed when the
`contents of the storage unit “counter” has reached up to the
`value 900,000. When this happens, the programme 23 will
`cause the storage unit “counter” to be set to zero, and the ;
`“hour counter” storage unit to be increased by 1. At the same
`time, the programmewill ensure that the new value of the
`storage unit “hour counter”ts transferred to a corresponding
`storage unit (hour counter) in the external EEPROM 14. The
`actual number of hours for which the hearing aid has been 2
`in operation will thus always be able to be read out from the
`external memory 14.
`The programme24 (Prog. change check) serves to check
`whether a change should be made to another programme,
`e.g. if the “hour counter” storage unit has reached one of the
`stored limit values, or if the user by the activation of an
`external pushbutton causes an interrupt with the view to
`changing between two or more conditions or programmes.
`The object of the Programme 25 (Check DTMF)isto test
`whether the data which is currently being handled in the
`block contains signals which will give rise to the implemen-
`tation of an updating of the hearing aid, such as e.g. a
`zero-setting of the “hour counter” storage unit in the internal
`data-RAM 11 and in the external EEPROM 14, or an
`updating of the limit values which are stored in the external
`EEPROM 14, and possibly a changing of other data in the
`data-RAM 11, the program-RAM 10 and/or the external
`EEPROM 14. These signals, which in the following are
`referred to as reactivation signals, can be any form of coded
`signals which can be recognized during data processing by
`the programme25.
`For example, use can be made of the well-known DTMF
`signals (Dual Tone Multi-Frequency), where two simulta-
`neous pure tones are used to signal a given digit between 0
`and 9. In an FFT-basedstructure as that described above,it
`is relatively simple to test whether there are DITMFsignals
`in those signals, which are fed into the digital signal pro-
`cessing and adaptation circuit 6 from the microphones 2.
`The programme 25 can thus detect such DTMEFsignals and,
`providing a given combination is detected, can activate a
`special programmestored in the external EEPROM 14. The
`special programmecan, for example, reset to zero the “hour
`counter” storage unit in the internal data-RAM 11 andin the
`external EEPROM 14 and/or set a new maximum value for
`the utilisation time, which maximum value can be stored in
`the external EEPROM 14. Finally, by transferring changes
`from the external EEPROM 14 to data-RAM 11 and
`program-RAM 10, the special programmecan carry out an
`updating or changing of the data and/or programmesfor the
`digital signal processing.
`The reactivation signals, such as e.g. DTMFsignals, can
`be introduced in the signals from the sound transducers,e.g.
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`US 6,741,712 B2
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`7
`in the form of a
`stored limit values will be effected, e.g.
`writing-up for the expiry of the next subscription period, or
`alternatively a setting of the summed-up utilisation time to
`zero. Moreover, e.g. when a habituation system is used, a
`changing of the parameters and/or programmes which are
`used for the signal processing will take place, e.g. by the
`selection from the EEPROM of new data and/or pro-
`grammes which are to be used in connection with the
`operating programme. Finally, a new code can possibly be
`selected for the reactivation signals, and this code will then
`be that which is expected to be used at the next updating of
`the hearing aid.
`The said limit valucs for the utilisation time can be
`
`10
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`15
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`determined in different ways. For example, an upper limit
`value can be entered which corresponds to the lifetime it is
`desired to give the hearing aid, e.g. 3 years. Such a deter-
`mination is encumbered with considerable uncertainty, in
`that the user pattern is not known. Normally, the daily use
`will be estimated to be 16 hours, so that an upperlimit of 3
`years will correspond to a summed-up utilisation time of ;
`approx. 18,000 hours. After a certain period of time, during
`a service visit to the dealer/audiologist, the utilisation time
`can, however, be read out from the hearing aid to a PC
`programme, andsince the date on which the hearing aid was
`taken into use is known,this provisionalutilisation time can
`be used to estimate the average daily use with greater
`precision, so that new limits can then be entered with a
`greater degree of certainty.
`Whatis claimedis:
`
`1. A hearing aid which comprises a sound transducer, an
`analogue-digital converter, a digital processing and adapta-
`tion circuit for the processing of digital signals, correspond-
`ing to audio signals which are received by the transducer,
`storage units for the storage of data and programs for the
`digital processing and adaptation circuit, a digital-analogue
`converter, a sound generator, a counter element for the
`registration of utilization time, and a storage unit for the
`storage of utilization time, wherein the counter element
`contains a counter which registers that time for which the
`hearing aid has been in use, that the storage unit for the
`storing of the utilization time comprises a non-volatile
`memory unit in whichthe utilization time is summedup,that
`the hearing aid is arranged in such a mannerthat a com-
`parison is made between the contents of that part of the
`non-volatile memory unit in which the summed-up utiliza-
`
`40
`
`8
`tion time is stored and one or more limit values, and that
`when one or more of the limit values has been reached, a
`special function is initiated.
`2. The hearing aid according to claim 1, wherein the
`special function which is initiated when a limit value is
`reached is a deactivation of the hearing aid.
`3. The hearing aid according to claim 1, wherein the
`special function which is initiated when a limit value is
`reached is an alarm function.
`
`4. The hearing aid according to claim 1, wherein the
`special function which is initiated when a limit value is
`reached is a changing of parameters and/or programs which
`are stored in the digital processing and adaptation circuit.
`5. The hearing aid according to claim 1, wherein the
`digital adaptation and signal processing circuit is arranged to
`detect
`the presence of reactivation signals in the digital
`signal flow and, depending on the presence of such signals,
`to initiate one or more special functions.
`6. The hearing aid according to claim 5, wherein the
`hearing aid is arranged in such a mannerthat upon detection
`of a reactivation signal, a zero-setting is carried out of that
`part of the non-volatile memory unit in whichthe utilization
`time is summed up.
`7. The hearing aid according to claim 5, wherein the
`hearing aid is arranged in such a mannerthat upon detection
`of a reactivation signal, there is carried out an increase of
`one or more of the limit values with which the summed-up
`utilization time is compared.
`8. The hearing aid according to claim 5, wherein upon
`detection of a reactivation signal, a changing of parameters
`and/or programs is also carried out.
`9. The hearing aid according to claim 5, wherein the
`hearing aid is arranged in such a mannerthatthe reactivation
`signals are introduced into the hearing aid’s digital signal
`flow, this being effected by supplying special audio signals,
`corresponding to the reactivation signals,
`to the hearing
`aid’s transducer.
`10. The hearing aid according to claim 5, wherein the
`hearing aid is arranged in such a mannerthatthe reactivation
`signals are introduced into the hearing aid’s digital signal
`flow, in that the hearing aid has a numberof code keys with
`which a special code, corresponding to the reactivation
`signals, is fed into the hearing aid.
`
`
`
`

`

`UNITED STATES PATENT AND TRADEMARKOFFICE
`CERTIFICATE OF CORRECTION
`
`PATENT NO.—: 6,741,712 B2 Page 1 of 1
`
`
`DATED
`: May 25, 2004
`INVENTOR(S): Nikolai Bisgaard
`
`It is certified that error appears in the above-identified patent and that said Letters Patent is
`hereby corrected as shownbelow:
`
`
`Column 2
`Line 38, replace “can be, coded signals,” with -- can be coded signals,--
`
`
`Column 3
`Line 1, replace “connection white” with -- connection while --
`Line 46, delete “FIG.”
`
`
`Column 7
`Lines 40 and 42, delete “that”
`
`
`Column 8
`Line 1, delete “that”
`
`Signed and Sealed this
`
`Fourteenth Day of December, 2004
`
`om WEae
`
`
`
`JON W. DUDAS
`Director of the United States Patent and Trademark Office
`
`