WO1996013212A1

WO1996013212A1 - Handheld recording audio-visual stethoscope

Info

Publication number: WO1996013212A1
Application number: PCT/FI1995/000568
Authority: WO
Inventors: Tommi Sakari Lukkarinen
Original assignee: Tommi Sakari Lukkarinen
Priority date: 1994-10-28
Filing date: 1995-10-13
Publication date: 1996-05-09
Also published as: EP0788330A1; FI98981C; FI945076A; AU3700595A; FI945076A0; FI98981B

Abstract

The verbal observation methods of auscultative findings of the human body are inaccurate. Various technical solutions have previously been invented for the registration and analysis of auscultative findings. But never before have the invention drawn any special focus on the convenience of the solution. A technical solution to this problem is given in the present invention, the handheld audio-visual recording audio-visual stethoscope. The solution is based on the attachment of the listening means (1), the sound transducer (2) and of the registration circuit (9) onto the portable main unit (3). The present inventional device amplifies, registers and replays sounds. By including a display to the present invention the registered sounds can also be analysed visually.

Description

HANDHELD RECORDING AUDIO-VISUAL STETHOSCOPE

The present invention relates generally to diagnostic auscultation and, more particulary, to 5 handheld recording stethoscopes.

The present invention, as described in the first patent claim, is an small diagnostic device, and designed for use when listening, registering, repeating and visually observing auscultative findings.

10 Auscultation refers to the method of carrying out basic clinical examination of the sounds of the human body; a major part of each doctor's skills. Especially, when exarnining the functioning of a child's heart, auscultation is the foremost examination method. Despite the development of techniques in the field of sound amplifiers and signal processing, the

15 traditional acoustic stethoscope is still the most popular device used in auscultation due to the fact that it is simple and practical to use. However, the acoustic stethoscope does have its weaknesses. When the sound to be heard is weak or the hearing of the observer poor, performing an analysis of the auscultative findings may become di ficult. Noises from the surrounding environment may also affect the procedure. On the other hand, practise and a

20 long experience in clinical examination is needed before a thorough analysis of body sounds can be performed. The strongest defect, however, is the fact that no objective documentation is possible, analysis must be performed verbally. Thus the different judgements given verbally by separate observers may differ to a great extent and an objective analysis of the auscultative findings becomes impossible.

25

Several electronic devices with the purpose of solving the problems dealing with the procedures of listening, registering and analysis of auscultative findings have been invented. The U.S. Pat 5 165 417 introduces a system which automatically detects any additional sounds coming from the lung area. An electronic stethoscope system described in the U.S Pat 4 770

30 189 connects several separate stethoscopes to a central unit. A computer based stethoscope analysis system is presented in the U.S Pat 4720 866. This system changes the detected sounds into electronic signals and uses a frequency analysis method to analyse the registered sounds. The U.S Pat 4428 381 includes a monitoring device through which it is possible to observe the functioning of a prosthetic heart valve. The diagnosis of the respiration system and sounds can be carried out with the use of a device described in U.S Pat 3 990435. A device and method for use in the analysis of heart indication sounds is described in the PCT patent WO 92/03094.

The U.S Pat 5 025 809 describes a recording digital stethoscope, which combines a series of features found in the traditional stethoscope and the registering stethoscope. According to the description the chestpiece of the stethoscope is connected to a tubular pipe which leads the traditional standing air to the case and ear-pieces connected to the end of the tube so that listening of the sounds is done in a traditional acoustic manner. The problem concerning this invention is the fact that the chestpiece and the case containing the electronic system are separate, which makes the device extremely difficult to use.

U.S. Pat. 5 218 969 describes an intelligent stethoscope, which includes an electronic circuit connected parallel with the acoustic stethoscope. The electronic circuit can preview the signals on a display included. Furthermore, a method which makes the differentiation between different heart sounds possible is given. This invention carries a problem similar to the one attached to the U.S Pat 5 025 809. The device is difficult to use because the chestpiece of the stethoscope is separate from the display and the operation controls.

U.S Pat 4 878 501 describes an electronic stethoscope, which contains an electrical amplifying circuit and a radio transmitter. The stethoscope transmits the signals wirelessly to an external registering device. The U.S Pat 4 170 717 and 4254 302 describe an electronic stethoscope, which has an electronic amplifying circuit and adapters which can be used to lead the signal given by the amplifying circuit to an external device for registration or display, connected to the chestpiece of the stethoscope. The problem concerning these solutions (U.S Pat 4 878 501, 4 170 717 and 4 254 302) is the fact that they do not include an internal registration device. Thus, when a doctor needs to register the auscultative findings, s/he needs to control a separate registering device along with handling the stethoscope. Computers may be used to register and analyse auscultative findings. By attaching a sound card and by using a separate listening means with a microphone attached, can the auscultative findings be registered into the memory of the computer in digital form. The problem concerning these commercial solutions is the same as with the previous improved stethoscopes. The registering procedure is performed either by using the keyboard or the mouse attached to the computer and is separate from the listening unit itself.

A closer observation of the previous solutions presents a surprising notion that none of the inventions take the convenient use of the device into account. This applies especially in sound registering situations. Often the chestpiece, which is held close to the part of the body being listened to and which often contains the sound transducer, and the registering circuits are separated from each other. Furthermore, the recording controls are placed in a separate registering unit. The separation of these parts, the chestpiece, the sound transducer and the registering and control means, makes the use of these devices even more complicated compared to the use of the traditional acoustic stethoscope. The reason for this is simply the fact that two hands are needed in the listening procedure; one to use the chestpiece and the other to operate the separate control and registering equipment.

A device designed according to the present invention provides a solution to the practical problems described above by attaching the listening means to a handheld main unit. The handheld main unit includes means which transform acoustic waves into electronic signals, register the signals and display the quantities connected to the signals, and also control these functions and transmit the information to external devices. The characteristic features of the present invention are found in the identification part of the first patent claim.

Several advantages can be achieved through this invention. The function of this device is independent of an external power supply since the power may be supplied from an internal power supply. Sound may be amplified with this invention so that weak sounds can be heard without misinterpretation. The registration of acoustic waves makes it possible to replay sounds again in the same form they were recorded, thus making exact comparing analysis of different sounds possible. Data transmission means make it possible to transmit sounds to external devices so that the information may be registered for a longer period of time to be later used in patient documentation, eg. in follow-up procedures and consultation. When the data transmission is carried out using wireless data transmission methods, the device is separated from other devices and its use made more simple due to fact that the device does not have to be connected through cables and data transmission can be carried out without the user actually performing the routines. The most important benefit of this inventional device, missing from any earlier inventions of the kind, is the intergration of the listening means, the acoustic wave transducer, the control and registration means into one small device. Thus the present inventional device is easy to use, portable and the acoustic waves under examination can be registered and controlled using only one hand with the other left free to perform other relevant functions. With the help of a visual display means the registered information can also be viewed and analysed visually. The display means are attached to the same main unit as the listening means, which makes it possible to view the display in the same direction as the part of the body being listened to, which in turn makes simultaneous analysis of both heard sounds and registered data possible. Further features for analysis can be added to the device through the electronic connections included in the registering means to help the observer make a diagnosis. When noise absorbant material is used to connect the listening means and the main unit, the distractive sounds produced when handling the device which could distract the listening procedure and alter the results of analysis are absorbed. The recording controls are familiar from other recording equipment, eg. video and tape recording devices, which makes it even more easier to become accustomed to the functions and use of this device. The use of normal head phones in place of traditional acoustic earpieces and tubes makes this device comfortable to use and frees the user from constraints affecting the length of tubes caused by absorbant materials used, and gives the user the freedom to select appropriate listening means into use. The following illustrations give a more detailed description of the invention.

FIG. 1 shows the present inventional device from above. FIG. 2 shows a longitudinal cross-section of the inventional device, with one preferred positioning of the parts.

FIG. 3 shows a longitudinal cross-section of one connecting method of the listening means and the main unit.

FIG. 4 shows a block diagram of the registration circuit of the present invention. FIG. 5 shows in detail the control means of the present invention.

FIG. 1 shows the present inventional device viewed from above. Listening means 1 which is pressed against the part of the body being listened to is at the top of FIG. 1. The acoustic wave transducer which transforms the pressure changes on the surface of the body into electrical signals is inside the listening means. Listening means 1 is attached directly to the portable main unit 3. The cover of the main unit has a display means 4, which may be used to view the auscultative finding visually. In addition to this, the control means 5, which are used to control the functions eg. recording, volume, data transmits of the inventional device, are also situated on the cover of the main unit. The data transmission means 6, which is used to transmit data to other data processing devices, is attached to the bottom edge of the main unit. Listening means eg. head phones (not shown in FIG. 1), which are used to listen to recorded or real time sounds are connected to the connector means for listening devices at the bottom edge of the main unit. A connection for external charging devices 8 used to charge the internal power supply, is situated at the bottom of the main unit.

FIG. 2 shows the longitudinal cross-section of the inventional device. At the top of the FIG. 2 there is a cross-section of the listening means 1 with the acoustic wave transducer 2 attached inside. An electret microphone, which is small enough, sensitive, inexpensive and uses low operation voltage can be used as an acoustic wave transducer. The listening means is attached to the main unit 3. The acoustic wave transducer 2 is attached with a thin wires (not shown in FIG. 2) to the registration circuit 9. The registration circuit is connected to the bottom of the main unit 3. There is a wire connection (not shown in FIG. 2) from the display means 4 and control means 5 to the registration circuit 9. Below the display means 4, inside the main unit there is an internal power supply 10 connected to the main unit. An appropriate choice for a power supply is a rechargeable battery. An inexpensive liquid crystal display can be used as a display means and a membrane keyboard can be used as control means. The internal power supply 10 is connected to the registration circuit 9 through wires (not shown in FIG. 2). The bottom of the FIG.2 shows a data transmission means 6 which is connected directly or by wires to the registration circuit 9. For example an infrared module, eg. HSDL 1000, can be used as a data transmission means, so that data transmission between the inventional device and the external data processing device will be carried out wirelessly. Due to the fact that the connector means for listening devices 7 and the external charging device connector 8 overlapp in depth with the data transmision means 6 in FIG.2, the FIG.2 shows only the data transmission means 6. The connector means for listening devices 7 and the external charging device connector 8 are connected to the registration circuit either directly or by wires.

The parts displayed in FIG. 2 can also be placed other alternative positions inside the main unit 3. For example the internal power supply 10 and the registration circuit 9 may be replaced by each other, and the data transmission means, connector means for listening devices and charging device connector can be placed at the sides of the main unit. Nevertheless, it must be noted how the present inventional device is to be held and the parts placed so that the data transmission means, listening means and recharging devices do not distract the use of the device. The advantage of the positioning of the parts in FIG. 2 is the fact that all the connectors are situated at the bottom of the main unit where they do not disturb the use of the device.

FIG. 3 shows a cross-section of one preferred way to connect the listening means and the main unit. The acoustic wave transducer is embedded either totally or partially into the fastening means 12 so that the sensitive head of the acoustic wave transducer is inside the fastening means and the connection pads 17 of the acoustic wave transducer outside the fastening means. There is a cylinder shaped space of air attached from one end to the sensitive head of the acoustic wave transducer and enlarging in conical form at the other end to meet a larger air space 18 inside the fastening means 12. The larger space of air 18 is either in direct contact with the part of body being examined or through a membrane when one is used in the listening means. The FIG. 3 shows a cup 11 which can be attached to the fastening device by screwing. The cup may alternatively be replaced by a membrane attached in similar manner. The cups and membranes used can either be ones available commercially, or models especially designed for use in the device in question.

FIG. 3 shows a solution where the fastening means is embedded into the main unit 13 and attached to the main unit with fastening nuts from the inside. The fastening nuts are screwn into the worms of the fastening means 12. There is a round distance plate 14 in between the fastening nut and the main unit which is designed to secure the listening means onto the main unit. In addition to this, FIG. 3 shows the wires 16 leading to the acoustic wave transducer registration circuit, which are connected to the connection pads 17 of the acoustic wave transducer. The listening means shown in FIG. 3 may also be attached to the main unit using several other methods. For example the fastening nuts 15 and the distance plate 14 on the fastening means may be replaced by screws which are attached to the fastening means 12 from inside the main unit. The listening means can also be glued onto the main unit. The simplest method of attaching the parts from an assembling point of view would be to design a matrix for the main unit where the listening device is a part of the main unit. This would decrease the need of separate components and add to the reliability of the device. Regardless of how the listening device and main unit are attached, the advantage achieved here is before all the fact that the listening means 1 of the stethoscope and the acoustic wave transducer are directly attached to the portable main unit 3, which makes it possible to use this registering stethoscope with only one hand. The fastening means has another function in absorbing distractive noises. When the main unit is handled some distractive noises may transmit onto the acoustic wave transducer and disturb the auscultation. When the fastening device is made out of noise absorbing material the noise transmitted from the main unit to the acoustic wave transducer can be decreased.

FIG. 4 shows a block diagram of the registration circuit. The acoustic wave transducer 2 is connected to a preamplifier 20 which amplifies the electric signal coming from the acoustic wave transducer. The preamplifier is connected to a filter 21, which controls the frequency features of the analogical systems. The filter 21 is connected to an analog-digital converter 2 which transmits the filtered analogical signals into digital samples. The analog-digital converter 22 is connected to a microcontroller 26, which processes the digital samples and registers them into a random access memory 28. The random access memory 28 is connected to the microcontroller 26. A digital-analog converter 23 is connected to a microcontroller 26. During the listening process the microcontroller 26 transmits the digital samples to the digital- analog converter 23. The digital-analog converter converts the digital signal back to an analogical form. The digital-analog converter 23 is connected to a conversion noise filter 24 which filters the high frequency noise made by the conversion process. The conversion noise filter is connected to a headphone amplifier 25 which amplifies the filtered signals. The headphone amplifier 25 is connected to the connector means for listening devices 7, to which external headphones may be connected and used to listen to signals coming either from the acoustic wave transducer 2 or sound samples previously registered into the random access memory 28. A data transmission circuit 29 is connected to the microcontroller 26 and to the data transmission means 6. The data transmission circuit 29 converts the digital signals of the microcontroller to correspond to the data transmission standards in use and the signals corresponding to the external data transmission standards so that they are equivalent to those of the microcontroller. The control means 5 which includes the registering control keys, is connected to the microcontroller. When the device is in use the microcontroller reads and controls the modes of the control keys. The display means 4 is also connected to the microcontroller 26, and it can display the functioning mode of the device as well as various information on registered signals. Also connected to the microcontroller 26 is the program memory 27 which includes the functioning program of the device and the power supply controls 30 which shuts down the internal power supply when the device is turned off. a connector means for the external recharging device is also connected to the power supply control 30.

The registration circuit shown in FIG. 4 can be realized in various different ways. The preamplifier 20, filter 21 and analog-digital converter 22 can be made out of separate components, and the same applies for the digital-analog converter 23, the conversion noise filter 24 and head phone amplifier 25. A simpler method would be to use ready-made micro chips with the functioning parts in question intergrated. Examples of such micro chips on the market are CS4215, AD1845 and TLC320AC01, which include the relevant amplifiers, filters and converters. In addition to this the micro chips already include a serial interface, through 5 which the micro chips can be connected to various microcontrollers. Various kinds of microcontrollers can be used, eg. 80C51, TMS7000, 68HC11, H8/500-series, or microcontrollers especially designed to processing digital signals, such as the TMS320 type processors. The read only memory and random access memory can be standard type memory modules (SRAM, DRAM, Flash-RAM). The data transmission circuits and power control 10 realizations can be carried out by ready-made intergrated micro chips (MAX232, MAX878, CS8130), which demand only several external passive components in addition to be able to function. An expert in the field will most certainly find several solutions for the electrical realization of the registering circuit.

15 The control means of the preferred embodiment are described in detail in FIG. 5. The control means include the power switch 50, volume increasing control key 51, volume decreasing control key 52, data transmission key 53, data receiving key 54, additional function key 55, recording key 60, stop key 61, replay key 62, first registration select key 63, and second registration select key 64. When the power switch 50 is pressed for the first time the

20 microcontroller signals the power supply control 30 to supply the device with power and activate the other functions on the registration circuit. When the power switch 50 is pressed for a second time the microcontroller signals the power supply controls to switch the power off from the registration circuit. When the microcontroller is activated it transmits the digital samples coming from the analog-digital converter 22 directly to the digital-analog converter

2523, whereafter the sound signals coming from the acoustic wave transducer can be listened to through listening devices eg. headphones, connected to this device. When the volume increasing control key 51 is pressed the volume increases. When the volume decreasing control key 52 is pressed the volume decreases. Volume increasing may be carried out in various different ways. For example when intergrated micro chips are used, both the

30 preamplifier and the output amplifier can be separately adjusted digitally. On the other hand, when the preamplifier and head phone amplifier are structured from separate components, a separate digitally controlled amplifying connector can be designed for use in these components, and then the amplification can be controlled digitally through a microcontrolle One method of amplifying sound is to multiply the digital samples with an appropriate facto so that when the digital samples are transformed back into analogical form they are either amplified or dampened depending on the quantity of the factor. The multiplication can be carried out using the microcontroller.

When the recording key 60 is pressed the microcontroller registers the samples coming fro the analog-digital converter into the random access memory 28. The microcontroller contin registering the samples until the stop key 61 is pressed or until the memory space reserved f the signal is full. When the replay key 62 is pressed the microcontroller scans the samples in the random access memory and transmits them to the digital-analog converter 23, and after the conversion 23, the filtering process 24 and amplification 25 they can be heard through th headphones attached to the connector means for listening devices. The microcontroller continues to repeat the registered sound samples until the stop key 61 is pressed or until all t samples have been repeated.

When the first registration select key 63 is pressed the microcontroller changes a memory address indicator used in the recording and repeating process to indicate the previous memo address. When the second registration select key 64 is pressed the indicator is changed to th position showing the following memory address. Using the memory space by dividing it into separate memory addresses several sound samples may be registered into one random access memory.

When the data transmission key 53 is pressed the microcontroller starts a data transmission process with an external device using the data transmission circuit 29. When the data recievi key 54 is pressed the microcontroller transmits digital information between the microcontroll and an external device. Standard data transmitting methods may be used in these processes. I addition FIG. 5 shows an additional function key 55 which can be used to perform other functions. For example by pressing the additional function key 55 a sound sample may be viewed visually on the display panel and the function of the control keys converted so that they can be used to observe certain parts of the sound sample in particular, or the additional function key can activate an analysis of the sound sample with the results of the analysis appearing on the display panel.

An expert in the field of electrical engineering and design will certainly find different variations for the control devices. The control keys can be adapted for example from devices already familiar to users, such as number and control keys on calculators or telephones. Independent of the positioning of the control devices the appropriate control and registering functions have to be able to be performed with this inventional device.

The present inventional device may be carried out in several different variations. The simplest solution is to design the device to function as a certain computer connected remote control. The control devices may consist of for example the recording key, the registering circuit may have been replaced by wires attached to the data transmitting means from the acoustic wave transducer, external headphone set and recording key. A wire is used as a data transmitting means. Due to the fact that the registration circuit contains only passive connections all the active eletronics is situated in the external data processing devices, which in this case may be a computer equipped with a sound card. Because current computer sound cards all contain microphone and headphone interfaces, the acoustic wave transducer and and the external headphones can be attached to these interfaces directly through the data transmission means. In addition to this most computers also contain a port which normally is used to connect a game control to the computer. Here the interface in question can be used to transmit the control signal given by the recording key to the computer. The device functions in the way described as follows. The computer processes a program which controls the sound card and the recording process. The program continuously scans the sound signals coming from the data processing interface to the microphone interface and transmits the signals back to the external head phones through the data transmitting means of the device. The program scans the functioning of the recording key in the same manner. When the user presses the recording key on the device, the state of the port changes and the program begins to register the signals into the memory of the computer. The registering process continues until the user frees the recording key. The program can be used to determine the destination of the incoming sound, to repeat and observe the visually registered sounds.

The simple device solution described above may be enlarged modularily. First of all other registration control keys can be added to the device, such as replay, first and second registration select keys. When active electronics is applied to the registration circuit, such as preamplifiers, an internal power supply and power switch will become necessary. The volume control can be adapted by adding a headphone amplifier which is equipped with a volume control. When it is necessary for the device to be able to register and repeat sounds digitally without an external data processing device such as a computer, the registration circuit must include a prefilter, an analog-digital converter, a microcontroller, a digital-analog converter, a conversion noise filter, and a random access memory. Then the analogical signals can be converted into digital form and registerd into the memory. When the registered sounds are replayed the sounds are converted back into analogical form and transmitted to the head phone amplifier. The processes are controlled by the microcontroller. Furthermore, a display can be attached to the main unit, through which the registered data may be observed visually.

Despite the fact that only few applications have been presented, an expert in the field may find various other combinations of the device which still are in the scope of the claims. The figures and descriptions presented above are not designed to give limits to the present invention but t illustrate the invention in question.

Claims

I CLAIM:

1. A handheld audio-visual registering device designed to register and audio- visually display sounds coming from the parts of the body under examination, such as the heart and the respiration organs, comprising; a listening means (1), which contains a sound transformer means (2) for transforming sound pressures into electrical signals, for receiving said sounds coming from the parts of the body; and a main unit (3) which contains a registration means (9) for registering electrical signals; control means (5) for controlling the registeration procedure, a data transmission means (6) for transmitting registered signals to and from other data handling devices; characterised by the said listening means (1) and the said main unit (3) are essentially and conveniently an intergrated whole.

2. A handheld audio-visual registering device according to Claim 1, characterised by the said listening means (1) is attached to the said main unit (3) with a fastening means (12), which is designed to absorb acoustic vibrations with the purpose of preventing distracting noise, eg. caused by handling the main unit, from being carried to the said listening means (1) from the said main unit (3).

3. A handheld audio-visual registering device according to Claim 1 or 2, characterised by the said registration means (9) contains a memory means (28), such as a Flash-type random access memory, for recording the said registered signals.

4. A handheld audio-visual registering device according to Claim 1, 2 or 3, characterised by the data transmitting means (6) for transmitting the data wirelessly with the help of eg. electromagnetic radiation, infrared radiation or ultrasound.

5. A handheld audio-visual registering device according to Claim 1, 2, 3, or 4, characterised by the said registering means (9) contains an indicator means (4), such as a graphical display, for analysϋng the registered signal visually. 6. A handheld audio-visual registering device according to Claim 1, 2, 3, 4 or 5 characteris by the said registering means (9) contains a connector means (7) for connecting an external listening means, such as head phones, for monitoring the registered signal.

5 7. A handheld audio-visual registering device according to Claim 1, 2, 3, 4, 5 or 6 characterised by the said main unit (3) contains an internal power supply means (10), such a rechargeable battery or alkali battery, for supplying power the the said registering means (

8. A handheld audio-visual registering device according to Claim 1, 2, 3, 4, 5, 6 or 7 10 characterised by the said control means (5) form a plane figure.

9. A handheld audio-visual registering device according to Claim 1, 2, 3, 4, 5, 6, 7 or 8 charaterised by the said control means (5) include at the least a recording key (60).

15 10. A handheld audio-visual registering device according to Claim 1, 2, 3, 4, 5, 6, 7, 8, or 9 characterised by the said control means (5) include a registration selection key (64).

AMENDED CLAIMS

[received by the International Bureau on 25 March 1996 (25.03.96); original claims 1,2 and 4-8 amended; remaining claims unchanged (2 pages)]

1. A handheld audio-visual registering device designed to register and aurally and visually represent acoustic waves coming from the parts of the body under examination, such as the heart and the respiration organs, comprising; a receiving means (1) for receiving said acoustic waves coming from the parts of the body, the said receiving means contains an acoustic wave transformer means (2) for transforming acoustic waves into electrical signals; and a main unit (3) which contains a registration means (9) for registering electrical signals and a control means (5) for controlling the registeration procedure; characterised by the said receiving means (1) and the said main unit (3) are essentially and conveniently integrated in such a way that the whole device is operable with one hand and the said control means (5) may be seen simultaneously at the location of the registering.

2. A handheld audio- visual registering device according to Claim 1, characterised by the said receiving means (1) is attached to the said main unit (3) with a fastening means (12), which is designed to absorb acoustic vibrations with the purpose of preventing distracting noise, eg. caused by handling the main unit, from being carried from the said main unit (3) to the said receiving means (1).

4. A handheld audio-visual registering device according to Claim 1 or 2 or 3, characterised by the said registration means (9) contains a data transmission means (6) for transmitting registered signals to and from other data handling devices.

5. A handheld audio- visual registering device according to Claim 4, characterised by the said data transmitting means (6) transmits the data wirelessly with the help of eg. electromagnetic radiation, infrared radiation or ultrasound.

6. A handheld audio-visual registering device according to Claim 1, 2, 3, 4 or 5, characterised by the said registering means (9) contains an indicator means (4), such as a graphical display, for analysing the registered signal visually.

7. A handheld audio-visual registering device according to Claim 1, 2, 3, 4, 5 or 6 characterised b the said registering means (9) contains a connector means (7) for connecting an external listening means, such as head phones, for monitoring the registered signal.

8. A handheld audio-visual registering device according to Claim 1, 2, 3, 4, 5, 6 or 7 characterised by the said main unit (3) contains an internal power supply means (10), such as a rechargeable battery or alkali battery, for supplying power to the said registering means (9).

9. A handheld audio-visual registering device according to Claim 1, 2, 3, 4, 5, 6, 7 or 8 charaterise by the said control means (5) include at the least a recording key (60).

10. A handheld audio-visual registering device according to Claim 1, 2, 3, 4, 5, 6, 7, 8, or 9 characterised by the said control means (5) include a registration selection key (64).