WO2006032101A1

WO2006032101A1 - Hearing testing

Info

Publication number: WO2006032101A1
Application number: PCT/AU2005/001456
Authority: WO
Inventors: Robert Henry Eikelboom; Marcus David Atlas; Mark Andrew Gallop; Andrew James Martlew
Original assignee: The Lions Ear And Hearing Institute
Priority date: 2004-09-23
Filing date: 2005-09-23
Publication date: 2006-03-30

Abstract

A computer sound peripheral device (10) for removable attachment to a computer (52,53) to test a subject's hearing. The peripheral device comprises a signal input port (24) for receiving a signal from driver software (55) via the computer, the software operable to select a tone and amplitude of the signal to be generated; a converter (30) for converting the signal representative of the selected tone; an amplifier (32) for amplifying the converted signal; and an output port (14,16) for connection to a set of headphones (36) to be worn by a subject during testing. The amplified signal provided at the output port is within a frequency range and calibrated with an accuracy A and is further within a sound level range and calibrated with an accuracy B. A system to test a subject's hearing is also described where the system comprises a computer, driver software installed on the computer; and a computer sound peripheral device as described above where the device is removably attachable to the computer.

Description

"Hearing testing"

Technical Field

This invention concerns a computer sound peripheral device for removable attachment to a computer to test a subject's hearing. In addition the invention concerns a system, and a method, to test a subject's hearing and a software program.

Background Art

Hearing testing is a common medical test that is performed by an audiologist. An adult's hearing is often tested in the case of age-related or noise induced hearing loss prior to fitting of hearing aids. A child is typically tested when hearing loss is suspected due to poor language development, poor performance at school, or when a child is suffering from middle ear disease.

Testing generally involves the presentation of pure tones or other calibrated sounds through a set of headphones and one ear is tested at a time. The test is carried out in a sound proof booth, or at least in a very quiet environment. The amplitude of each tone is decreased as the subject responds to the sound by activating a press-button. When the subject fails to respond to the sound, the audiologist raises the sound level slightly until the subject indicates that they can again hear the tone. The sound level is raised and lowered a few times to establish this threshold. This procedure follows an established protocol.

The process above describes air conduction testing, that is where sound pressure waves travel down the ear canal, vibrate the tympanic membrane (ear drum) and the three ossicles, which in turn causes the fluid in the cochlear to move over the hair cells. To test the sensori-neural part of hearing, that is the sensing in the cochlear, and the conduction through the nerves to the brain, a vibrating transducer is placed against the temporal bone just behind the ear or against another part of the skull (bone- conduction). This vibration is conducted through the bone to the cochlea.

Audiometers are used in the testing of hearing, both for air-conduction and bone-conduction testing. Typically an audiologist records the results of a test. Audiometers are used to deliver the tones and the frequency and amplitude or the tones must have a high degree of accuracy. Audiometers must be calibrated together with the headphones used in conjunction with the audiometer. Whilst a few portable audiometers are available, they are at best heavy and cumbersome. Desktop audiometers are more common. Disclosure of Invention

In a first aspect, the invention is a computer sound peripheral device for removable attachment to a computer to test a subject's hearing, the peripheral device comprising: a signal input port for receiving a signal from driver software via the computer, the software operable to select a tone and amplitude of the signal to be generated; a converter for converting the signal representative of the selected tone; an amplifier for amplifying the converted signal; and an output port for connection to a set of headphones to be worn by a subject during testing;^' wherein the amplified signal provided at the output port is within a frequency range and calibrated with an accuracy A and is further within a sound level range and calibrated with an accuracy B.

In a second aspect, the invention is a system to test a subject's hearing, the system comprising: a computer operable to generate signals; driver software installed on the computer, the software operable to select a tone and amplitude of a signal to be generated; and a computer sound peripheral device removably attached to the computer, the peripheral device comprising: a signal input port for receiving a generated signal representative of the selected tone from the computer; a converter for converting the generated signal representative of the selected tone; an amplifier for amplifying the converted signal; and an output port for connection to a set of headphones to be worn by a subject during testing; wherein the amplified signal provided at the output port is within a frequency range calibrated with an accuracy A and is within a sound level range calibrated with an accuracy B.

In a third aspect, the invention is a system to test a subject's hearing, the system comprising: a first and a second computer, each remote from, but in communication with the other, the first computer operable to generate signals; driver software installed on the first computer, the software operable to select a tone and amplitude of a signal to be generated; a computer sound peripheral device removably attached to the first computer, the peripheral device comprising: a signal input port for receiving a generated signal representative of the selected tone from the first computer; a converter for converting the generated signal representative of the selected tone; an amplifier for amplifying the converted signal; and an output port for connection to a set of headphones to be worn by a subject during testing; wherein the amplified signal provided at the output port is within a frequency range calibrated with an accuracy A and is within a sound level range calibrated with an accuracy B; and control software installed on the second computer so that the operation of the first computer to test a subject's hearing is under the control of the second computer.

The selected tone may include a calibrated pure tone at different frequencies and different amplitudes. The tone may be, or further include, a warble tone, various noise or combinations of frequencies appropriate to drive a transducer used for hearing testing. Hearing testing includes, but is not limited to, any one or more of air conduction testing, bone-conduction testing, and speech testing. A warble tone is advantageous when testing a subject who has tinnitus.

The sound peripheral device may include an integrated circuit, a USB-audio chip, or the like for generating signals. . The first or second computers may generate the tone in real-time, or may use one or more of a number of stored tones.

The amplified signals provided at the output port may be within a frequency range of 0 Hz to about 12 kHz. The device is operable such that the upper limit of the amplified tones exceeds 12 kHz. Preferably testing is performed in frequency increments, for instance, but not limited to, 250 Hz, 500 Hz, 1000 Hz₅ 2000 Hz, 4000 Hz and 8000 Hz. The ANSI standard requires an accuracy of less than 3%. The frequency of the amplified signals may be calibrated with an accuracy of about 0.5%.

The amplified signals provided at the output port may be within a sound level range of

0 dB to about 95 dB and accurate to within about 2 dB. The harmonic distortion attenuation may be over 50 dB of the first harmonic, exceeding the ANSI standard of 4O dB.

The sound peripheral device may be calibrated according to ANSI standards for audiometric assessment. ^

The sound peripheral device may be a standard, off the shelf, plug and play removable sound peripheral device. The device may be incorporated into a sound card. The peripheral device may include a plurality of ports. These ports may include any one or more of an output port for connection to a transducer suitable for hearing testing of a subject, an output port for voice communication between operators of respective computers, an input audio signal port, a video in port and an input for a means indicative of a subject's response. The input port for a subject's response may receive an indicator device such that a subject undergoing testing can indicate when they have heard a sound.

A USB connection may connect the sound peripheral device to the first computer. Optionally an IEEE 1384 connector, or other like connection, may connect the sound peripheral device to a computer, or the first computer.

The driver software may be remotely operable. The headphones are not limited as to type. For example the headphones may be insert earphones or over-the-ear headphones.

The first and second computers may communicate over the world wide web/internet.

The system may further comprise a server to establish a network connection between the first and second computers. The server may further verify the identity of the respective computers and/or the users of the respective computers. The server may store subjects' biographical and/or clinical history in a database. At least a portion of the database may be accessible from the first computer. Optionally, the second computer may include a database and be further operable to perform the above functions.

The system may further comprise a video device to enable a person located at the second computer to view a subject located at the first computer who is undergoing or who is about to undergo a hearing examination.

The signal representative of the selective tone to be generated, together with voice data and visual data, may be integrated into one stream of information. The information may be prioritised such that the signal representative of the selective tone to be generated and the response from a subject receives priority.

The device/system may further include a sound level meter to monitor the ambient noise levels present at the remote location. In a fourth aspect, the invention is a method for remote testing of a subject's hearing, the method comprising: establishing a connection between a first and a second computer, each remote from, but in communication with the other; operating the second computer to remotely control the operation of the first computer such that the first computer selects a tone and amplitude of a signal to be generated to test a subject's hearing; generating the signal representative of the selected tone; and amplifying the generated signal through headphones worn by the subject whose hearing is being tested; wherein the amplified signal is within a frequency range and calibrated with an accuracy A and is further within a sound level range and calibrated with an accuracy B.

According to the method of the invention, the first and second computers may communicate over the world wide web/internet. A computer sound peripheral device in accordance with the first aspect, or any embodiment thereof, may generate and amplify the selected tones and may be removably attached to the first computer. The method may further include determining whether the amplified tone was heard by the subject, and if the amplified tone was not heard by the subject increasing the amplitude of the tone. The method may further include recording the threshold hearing of the subject at the tested frequency. The method further include forwarding the results of the hearing test to a third party. The third party may be the subject's local doctor or a referral specialist.

In a fifth aspect the invention is a software program, installable on a first computer and operable to select a tone of a signal to be generated and amplified for the testing of a subject's hearing such that the amplified signal is within a frequency range and calibrated with an accuracy A and further within a sound level range and calibrated with an accuracy B and wherein the operation of the first computer to test a subject's

^' hearing is under the control of a second computer remote from the first computer.

At least an embodiment of the invention provides a new approach to the audiological testing of subject's hearing. Rather than having to co-locate audiologists with subjects, be they in rural or remote areas, the invention requires only 'virtual co- location' by a network link. This greatly reduces the need for audiologists to travel long distances to get to these areas. Inhabitants of such areas or regions which lack on site audiological services can potentially receive much better service.

Advantageously, the sound peripheral devices of at least an embodiment of the invention are relatively small and may be simply plugged and unplugged from a locally based computer. Therefore, the sound peripheral device and headset can easily be shipped back to an appropriate laboratory for periodic calibration.

Brief Description of Drawings

An example of the invention will now be described with reference to the accompanying drawings; in which: Fig. 1 is a schematic diagram of front and rear panels of a sound peripheral device for removable attachment to a computer to test a subject's hearing;

Fig. 2 is a schematic diagram of a system for the remote testing of a subject's hearing which incorporates the sound peripheral device as shown in figure 1 ; Fig. 3 is a flow diagram of the steps required to conduct a remote hearing test; and

Fig. 4 is a schematic illustration of an interface panel of a local computer for use by an audiologist.

Best Mode for Carrying Out the Invention

Figure 1 schematically illustrates the front and rear views of a sound peripheral device 10 which is incorporated into a system (figure 2) for remote hearing testing. The sound peripheral device 10 is provided with a number of input and output ports. On the rear panel of the sound peripheral device 10 are respective audio output ports 14 and 16 for connection to right and left channels of headphone speakers 36, a bone conductor output port 18 for connection to a transducer 38 for hearing testing, an audio output port 20 for voice communication, and a computer port 22 into which a cable may be plugged so as to removably connect the sound peripheral device 10 to a USB connector on the rear of a PC 52 or laptop 53. The front panel of the sound peripheral device 10 includes an audio input port

24, a subject response input port 26 into which a cable from a hand held clicker can be plugged into, and a volume control dial 28.

Contained within the sound peripheral device 10 is a converter in the form of a digital to analogue converter 30 which is capable of receiving a streaming digital signal representative of a pure tone, noise, warble tone, speech or music from a file stored on the hard drive of computer 52, or 53 to which the peripheral device 10 is connected to. The converter 30 converts the received signal into a stereo analogue signal. The computer 52, or 53 is able to generate the pure tones, warbles, as well as various sounds as stated above. The computer 52, or 53 is also able to generate the electrical signals for the transducer 38 used for hearing testing. The converter 30 is communicable with additional interfaces that enable the converter to be connected to other devices, such as general digital input/output (IO) connections. These IO's control analogue audio switches direct the audio to any one or more of the ports 14, 16, 18 or 20, and act as an input for the device plugged into the subject response connector 26. The device 10 further includes an amplifier 32 in communication with the converter 30 to amplify the converted signals representative of the selected tones. The frequency of the amplified tones are calibrated with an accuracy of approximately 3% and the sound level of the amplified tones are calibrated with an accuracy to within about 2 dB. The peripheral device 10 interfaces to the PC 52 via a databus 34. The converter 30 draws power from the bus 34. The system 50 is operable to enable an audiologist to test the hearing of a subject who is at a location remote from the audiologist. The system 50 includes a local computer 56 which communicates over the Internet 59. The remote computer may be a PC 52 or a laptop 53. The connection is fast enough to handle the flow of information between a local and remote computer. A sound peripheral device 10 is connected to each of the remote computers 52, 53.

The term 'local computer' refers to a computer operated by an audiologist or ear specialist. The local computer is located at the audiologist's facility. The term 'remote computer' refers to a computer at some location remote to the location of the local computer, generally an area in which the resident population does not have access to the services of such specialists.

The authentication server 58 is used to establish, communication over the Internet 59 between the local computer 56 and the remote computer 52. The server 58 acts an authenticator in the sense that it establishes the identity of the respective computers 52 and 56. Once the computers have been identified, the server 58 grants permission to the audiologist via a login user-name and password.

The communication between the computers is achieved using the Simple Object Access Protocol (SOAP). This is a protocol specifically developed for distributed computing and makes use of HTTP to transport XML messages. Serialised Java objects transmitted using Java sockets is another possible implementation. Software is installed on the respective computers 52, 56 to enable the audiologist to control the hearing assessment of a subject in a remote location. The respective software runs in a standard Internet browser window, and may be installed and upgraded online.

The audiologist, via the software on computer 56, is^ able to program the software 55 installed on the remote computer 52 to select a specific tone at a specified frequency and amplitude, and in turn, the software 55 prompts the computer 52 to generate in real-time digital representations of that tone. The tone may be a pure tone, warble tone, as well as various sound signals, which can be sent to the peripheral device 10. The local computer 56, or the server 58, houses a database 60 which stores a record of each subject's history including subject demographics and test results. The results from successive tests can be subsequently compared and the results of such tests can be printed and emailed to the subject's doctor.

In addition, a video camera 54 is linked to the remote computer 52, via a USB or IEEE 1384 connector. The video camera 54 enables a one-way visual link so that the audiologist or specialist controlling the hearing test from the site of the local computer 56 can visually monitor the subject.

The data input by the audiologist and which controls the remote computer 52 is transmitted over the Internet 59. Furthermore, data indicative of the responses from the subjects, and two-way voice and one-way video signals are further transmitted over the internet. These data, voice and video transfers are integrated into one stream of data. Tasks are prioritised so that the data to control the audio device 10 receives priority.

Figure 3 schematically outlines the steps involved in performing a generalised hearing test for an adult in accordance with the system 50. An audiologist based in Perth, Western Australia receives a call from a sole, general practitioner in the rural Kimberley region, step 105. The GP has a subject who is required to undergo an air conduction hearing assessment. Information about the subject is exchanged between the audiologist and the GP, step 110. The audiologist, or their assistant creates an electronic file for the subject which is stored in the database. An appointment is also booked for the subject, step 115. At the appropriate time the subject arrives at the GP 's premises for the assessment. A nurse or assistant is present at the doctor's surgery to assist the subject through the test. In this instance, both the local computer at the audiologist's facility and the remote computer at the nurse's premises have a high-speed network connection. The audiologist logs onto their computer 56 and accesses the relevant software.

The software installed on the audiologist's local computer 56 consists of a Graphical User Interface (GUI) 70 as illustrated in figure 4. To start the session, step 120, the audiologist activates the login button provided in the bottom right hand corner of the interface step. Having logged on, the audiologist is able to enter the subject's name and identity details such as gender and date of birth into fields in the top right hand corner of the interface. The audiologist enters his or her name and enters in the information. Any information pertinent to the subject is then retrieved from the database and appears in the upper left-hand corner of the interface 70, step 125.

Meanwhile the nurse connects the sound peripheral device to the computer 52. The software installed on computer 52 where the nurse is located has a GUI (not shown) which enables the nurse to enter subject information as well as displaying basic instruction from the audiologist. Its primary purpose is to control the sound peripheral device 10 and accept inputs, namely subject response, voice data, and video data, to enable the subject and/or the nurse to communicate with the audiologist.

The nurse, via the software, logs onto the Internet and accesses the authentication server 58 to establish communication with the audiologists computer 56, step 130. The nurse via the network connection 59, accesses certain areas of the database to prepare for the assessment and to record subject demographics. The nurse correctly positions the Telephonies TDH 39P headphones on the subject's head, step 135, and plugs the lead of the headphones into the sound peripheral device 10. The nurse generally assists the subject throughout the assessment.

The audiologist conducts the test according to standard clinical procedures. The audiologist is able to establish selective control parameters, step 140, such as setting and adjust the tones via the frequency window 72 on the GUI 70. The audiologist is able to ramp the frequency up or down by clicking on the touch pad cursors 74. An on- off tone warble touch pad 76 is provided as well as an interrupt, on-off touch pad 78. Similarly an amplitude window 80 is provided so that the audiologist can ramp the amplitude up or down by way of the touch pads 82. The amplitude is ramped in increments of either 10 dB or 5 dB. An external source on-off touch pad 84 is further provided. A masking amplitude window 88 is provided and able to be turned on and off 90. Again the audiologist is able to ramp the masking up or down by way of the touch pads 92.

In this instance, the audiologist indicates that the amplitude and frequency data is for the purposes of air conduction testing by touching sub screen 98 to get the desired display. The audiologist communicates to the nurse and subject, via the audio communication channel, general information about the procedure and indicates which ear is to be initially tested. To activate this channel, the audiologist presses the 'talk- over' button 95. The audiologist activates the touch pad 96 to indicate that the right ear is to be tested first. The audiologist is able to save 100 these settings, and the data indicative of these settings is stored on the subject's file in the database 60. A suitable frequency is selected as a starting point. Initially masking is not applied. The threshold for that frequency is then determined.

Having set the required start frequency and amplitude and communicated to the subject that the test is to begin, step 145, the audiologist activates the present tone touch pad 94 which then transmit the appropriate data to the software installed on the remote computer 52, step 150. The software 55 installed on the remote computer 52 accepts instructions from the local computer 56 to select the required tone. The computer 52 responds by generating a signal representative of the tone and the signal is streamed to the converter 30. The converter 30 receives the streaming signal and converts it into a stereo analogue signal. The analogue signal is amplified and played through the headphones worn by the subject, step 155.

In circumstances where the subject detects the tone, step 160, the subject responds by activating the hand clicker (not shown). This response is then transmitted over the Internet to the software installed on the audiologist's computer which responds by visually 79 and audibly alerting the audiologist.

The audiologist checks to determine whether the threshold has been determined for the particular frequency being tested. If the threshold has not been determined, step 165, then the audiologist increases or decreases the amplitude 82, step 170. Initially the amplitude is increased in 10 dB steps and thereafter in 5 dB steps up and down. This procedure is continued until the threshold is determined. Then, the audiologist checks to determine if the subject has been tested at all the required frequency steps within the test frequency range of 500 Hz to 10 kHz. If all frequencies have not been tested the audiologist instructs the software on the nurses computer to select a tone at an increased or decreased frequency, step 180. Otherwise, if all the frequencies for the right ear have been tested, the procedure from step 145 is repeated with masking applied. Thereafter, the procedure is repeated for the left ear, with and without masking.

The threshold of hearing for the subject at each frequency is recorded against the subject and stored in the database. The audiogram is displayed on the screen 78 as the results are recorded.

The test may then be repeated for bone conduction, initially masked and then unmasked.

At the completion of the assessment the subject is free to leave. The audiologist's assessment of the subject is emailed to the subject's doctor. At least annually, the sound peripheral device and headphones are packaged off to a laboratory for calibration purposes.

The above described device and system may provide new opportunities for audiologists to provide services to areas in need of audiological services, while not imposing on them the costs of travel and accommodation. This is particularly relevant to communities in sparsely populated areas which generally have inadequate access to health care. Although one embodiment of the invention has been discussed, it should be appreciated that such an embodiment is only one of the many utilising the principles of the invention. In an alternative embodiment, the system may further be utilised to enable rural health workers to obtain services from specialists based in city locations. A rural health worker having taken images of the ear canal and eardrum of a subject, is subsequently able to record a clinical history on the remote computer. These images are then able to be transmitted to the authentication server. The authentication server software alerts a specialist to access the subject images and data via a standard Internet browser. The specialists assessment of the subject is made on-line, and sent back to the health worker via an e-mail. If necessary the specialist may instruct the rural health worker to request that the subject be taken to their local facility so as to have a hearing test performed on line.

Another embodiment may be the testing of subjects located in metropolitan area sites, in a similar model to that used for pathology and radiology. Whilst the example has been described in relation to a subject attending the facilities of a nurse, if the subject is immobile, or within a nursing home for instance, the nurse or GP may take the audio device together a computer laptop to the subjects place of residence. It should be appreciated that not all locations currently have broadband access or access to other high speed network connections. In such instances In another embodiment the peripheral device may have an integrated circuit which has the ability to store or generate some or all of the digital representations of the various sound signals.

It is envisioned that with such a system, audiological assessment could be offered to residents residing in areas where there is a shortage of audiologists and could be offered to residents in rural and remote areas, mining sites and prisons. This will advantageously create export income, provide links to international clinics and practitioners, and help surgeons attract overseas subjects. Furthermore, it is envisioned that the system will be a very valuable resource for ear surgeons in that they will be able to offer some aspects of pre- and post-surgical assessment of their subjects, avoiding the need for long distance travel.

It will be appreciated by persons skilled in the art that numerous variations and/or modifications may be made to the invention as shown in the specific embodiments without departing from the spirit or scope of the invention as broadly described. The present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive.

Claims

CLAIMS:

1. A computer sound peripheral device for removable attachment to a computer to test a subject's hearing, the peripheral device comprising: a signal input port for receiving a signal from driver software via the computer, the software operable to select a tone and amplitude of the signal to be generated; a converter for converting the signal representative of the selected tone; an amplifier for amplifying the converted signal; and an output port for connection to a set of headphones to be worn by a subject during testing; wherein the amplified signal provided at the output port is within a frequency range and calibrated with an accuracy A and is further within a sound level range and calibrated with an accuracy B.

2. A device according to claim 1, where the converter is operable to convert signals representative of calibrated pure tones at a range of frequencies and a range of amplitudes.

3. A device according to claim 2, where the converter is operable to convert signals having frequencies within the range of 0 to about 12 kHz and with amplitudes within the range of 0 dB to about 95 dB.

4. A device according to any one of the preceding claims, where the converter is operable to convert signals representative of warble tones.

5. A device according to any one of the preceding claims, where the device is operable to drive a transducer for hearing testing.

6. A device according to any one of the preceding claims, where the converter is operable to convert signals from a file stored on the computer.

7. A device according to any one of the preceding claims 1 to 5, where the converter is operable to convert signals from the computer as they are generated.

8. A device according to any one of the preceding claims, where the amplified tones provided at the output port are within a frequency range of 0 Hz to about 12 kHz.

9. A device according to claim 8, where the frequency of the amplified tones are calibrated with an accuracy of less than about 3%.

10. A device according to claim 9, where the frequency of the amplified tones are calibrated with an accuracy of about 0.5%.

11. A device according to any one of the preceding claims 8 to 10, where the amplified tones provided at the output port are within a sound level range of 0 dB to about 95 dB.

12. A device according to claim 11₅ where the sound level of the amplified tones are calibrated with an accuracy to within about 2 dB.

13. A device according to claim 1, where the device is able to be calibrated according to American National Standards Institute standards for audiometric assessment.

14. A device according to any one of the preceding claims, where the device is a removable, plug and play device.

15. A device according to claim 14, where the device is incorporated into a sound card.

16. A device according to any one of the preceding claims, further comprising one or more of an output port for connection to a transducer suitable for hearing testing of a subject, an input audio signal port, and an input port for receiving a response from a subject.

17. A device according to any one of the preceding claims, where the driver software is remotely operable.

18. A system to test a subject's hearing, the system comprising: a computer operable to generate signals; driver software installed on the computer, the software operable to select a tone and amplitude of a signal to be generated; and a computer sound peripheral device removably attached to the computer, the peripheral device comprising: a signal input port for receiving a generated signal representative of the selected tone from the computer; a converter for converting the generated signal representative of the selected tone; an amplifier for amplifying the converted signal; and an output port for connection to a set of headphones to be worn by a subject during testing; wherein the amplified signal provided at the output port is within a frequency range calibrated with an accuracy A and is within a sound level range calibrated with an accuracy B.

19. A system according to claim 18, where the converter is operable to convert signals representative of calibrated pure tones at a range of frequencies and amplitudes.

20. A system according to claim 19, where the converter is operable to convert signals representative of frequencies within the range of 0 Hz to 12 kHz and with amplitudes within the range of 0 dB to about 95 dB.

21. A system according to any one of claims 18 to 20, where the converter is operable to convert signals representative of warble tones.

22. A system according to any one of claims 18 to 21, where the computer is operable to drive a transducer for hearing testing.

23. A system according to any one of the preceding claims 18 to 22, where the converter is operable to convert signals from a file stored on the computer.

24. A device according to any one of the preceding claims 18 to 22, where the computer generates the signal in response to instructions from the driver software.

25. A system according to any one of the preceding claims 18 to 24, where the amplified tones provided at the output port are within a frequency range of 0 Hz to 12 kHz.

26. A system according to claim 25, where the frequency of the amplified tones are calibrated with an accuracy of less than about 3%.

27. A system according to claim 26, where the frequency of the amplified tones are calibrated with an accuracy of about 0.5%.

28. A system according to any one of the preceding claims 25 to 27, where the amplified tones provided at the output port are within a sound level range of 0 dB to about 95 dB.

29. A system according to claim 28, where the sound level of the amplified tones are calibrated with an accuracy to within about 2 dB.

30. A system according to claim 18, where the device is able to be calibrated according to American National Standards Institute standards for audiometric assessment.

31. A system according to any one of the preceding claims 18 to 30, where the device is a removable, plug and play device.

32. A system according to claim 31, where the device is incorporated into a sound card.

33. A system according to any one of the preceding claims 18 to 32, further comprising one or more of an output port for connection to a transducer suitable for hearing testing of a subject, an input audio signal port and an input port for receiving a response from a subject.

34. A system according to any one of the preceding claims 18 to 33, where the driver software is remotely operable.

35. A method for remote testing of a subject's hearing, the method comprising: establishing a connection between a first and a second computer, each remote from, but in communication with the other; operating the second computer to remotely control the operation of the first computer such that the first computer selects a tone and amplitude of a signal to be generated to test a subject's hearing; generating the signal representative of the selected tone; and amplifying the generated signal through headphones worn by the subject whose hearing is being tested; wherein the amplified signal is within a frequency range and calibrated with an accuracy A and is further within a sound level range and calibrated with an accuracy B.

36. A method according to claim 35, further comprising determining whether the amplified signal was heard by the subject, and if the amplified signal was not heard by the subject modifying the amplitude of the signal. ,

37. A method according to claims 35 or 36, further comprising recording the threshold hearing of the subject at the tested frequency.

38. A method according to any one of claims 35 to 37, further comprising forwarding the results of the hearing test to a third party.

39. A software program, installable on a first computer and operable to select a tone of a signal to be generated and amplified for the testing of a subject's hearing such that the amplified signal is within a frequency range and calibrated with an accuracy A and further within a sound level range and calibrated with an accuracy B and wherein the operation of the first computer to test a subject's hearing is under the control of a second computer remote from the first computer.

40. A system to test a subject's hearing, the system comprising: a first and a second computer, each remote from, but in communication with the other, the first computer operable to generate signals; driver software installed on the first computer, the software operable to select a tone and amplitude of a signal to be generated; a computer sound peripheral device removably attached to the first computer, the peripheral device comprising: a signal input port for receiving a generated signal representative of the selected tone from the first computer; a converter for converting the generated signal representative of the selected tone; an amplifier for amplifying the converted signal; and an output port for connection to a set of headphones to be worn by a subject during testing; wherein the amplified signal provided at the output port is within a frequency range calibrated with an accuracy A and is within a sound level range calibrated with an accuracy B; and control software installed on the second computer so that the operation of the first computer to test a subject's hearing is under the control of the second computer.

41. A system according to claim 40, further comprising a server to establish a network connection between the first and second computers.

42. A system according to claim 41, where the server is operable to verify the identity of the respective computers and/or the users of the respective computers, and to store subjects' biographical and subjects' clinical history in a database.

43. A system according to claim 41, where at least a portion of the database is accessible from the first computer.

44. A system according to any one of claims 40 to 43, further comprising a video device to enable a person located at the second computer to view a subject located at the first computer who is the subject of a hearing examination.

45. A system according to claim 44, where control data which at least controls the tone generated, together with voice data and visual data, are integrated into a single stream of information.

46. A system according to claim 45, where the control data further includes data representative of a response from a subject undergoing testing.

47. A system according to claim 46, where the information is prioritised such that the control data and the response from the subject receives priority.

48. A system according to any one of claims 40 to 47, further comprising a sound level meter to monitor the ambient noise levels present at the remote location.