WO1999051144A1

WO1999051144A1 - Stress monitoring system

Info

Publication number: WO1999051144A1
Application number: PCT/AU1999/000252
Authority: WO
Inventors: Thomas Michael Park; Greg Cuneo
Original assignee: Thomas Michael Park; Greg Cuneo
Priority date: 1998-04-06
Filing date: 1999-04-06
Publication date: 1999-10-14
Also published as: AUPP283298A0

Abstract

A stress monitoring system comprising a computer work station operable by a user, said work station (1) including an input entry device (5) being manipulable by the user; a skin resistance measurement means (12, 13, 14) arranged in said data entry device for measuring at least a skin resistance of the user; processing means (30) associated with said skin resistance measurement means, for interpreting at least the measured skin resistance of the user in relation to a predetermined value, to establish a level of stress of the user; and output means (3) for outputting the established level of stress of the user.

Description

STRESS MONITORING SYSTEM

Field of the Invention

The present invention relates to monitoring systems and, in particular, discloses an arrangement by which biological stress values can be monitored.

Background Art

Modern workplace and home environments provide for varying levels of stress to be experienced by persons, often irrespective of the nature of activity being performed. These problems can be particularly pronounced in office and similar environs where individuals work, at least in part, with office equipment such as computers, terminals, copying machines and the like.

Increased levels of stress can impact on the health of anyone in the community and also on the productivity of one in the working or home environment or society. It is therefore desirable to identify situations where people become stressed so that corrective and hopefully ameliorating actions can be taken using self feedback or otherwise approaches.

Summary of the Invention

It is an object of the present invention to provide an arrangement by which stress levels can, at least, be monitored.

In accordance with one aspect of the present invention there is provided a system for monitoring stress in a biological entity, the entity being in at least occasional physical contact with an apparatus, said system comprising: detecting means configured within the apparatus for detecting a state of the entity in contact with the apparatus; processing means for processing the detected state, to assess a relative level of stress in the entity; and output means for outputting the relative level of stress of the entity. - 2 -

In accordance with another aspect of the present invention there is provided a stress monitoring system comprising: a computer work station operable by a user, said work station including an input entry device being manipulable by the user; a skin resistance measurement means arranged in said data entry device for measuring at least a skin resistance of the user; processing means associated with said skin resistance measurement means, for interpreting at least the measured skin resistance of the user in relation to a predetermined value, to establish a level of stress of the user; and output means for outputting the established level of stress of the user.

In accordance with still another aspect of the present invention there is provided a method of determining a stress level of a user of a computer workstation, said method comprising the steps of: providing at least two galvanic skin resistance contacts on user manipulatable portions of a data input device of the workstation, measuring a resistance between said contacts whenever said data input device is manipulated by the user in a pre-defined manner, and processing said measured resistance to establish a relative stress level of the user.

In accordance with still another aspect of the present invention there is provided a mouse pointing device comprising: at least two galvanic skin resistance contacts, each being located to be contactable with a single hand of a user of said pointing device; and a conversion device to provide an output signal from said pointing device, corresponding to a biological resistance between each of the contacts.

A system for determining a stress level of a user of a computer workstation, said system comprising: a mouse pointing device associated with the workstation, said mouse pointing device having at least two conductive electrical contacts exposed at a surface thereof - 3 -

and being arranged to enable a closed circuit with a hand of the user to be made whenever said pointing device is manipulated by the user in a pre-determined. manner, each of said contacts being connected to an input of a galvanic resistance measuring device which provides an electrical output signal in accordance with a connected resistance at said input, said electrical output signal being in turn connected to an input of a modulating device which provides an electrical pulsed output signal of varying frequency as a function of said electrical output signal, a processor associated with the workstation for executing a software application program including a subroutine which is called whenever said closed circuit is enabled, said subroutine including a calculation of an actual skin resistance value and a procedure for providing a message on a display associated with the workstation, wherein said calculation includes a subtraction of a reference value of resistance which corresponds to a resistance of the contacts when said closed circuit is not enabled, from said measured value.

Preferably, the input device comprises a mouse, joy stick, telephone handset or car steering wheel or other such devices touched periodically by human hand. Preferably the input device is connected to either a stand alone computer circuit board or computer or a local area network or Internet and the resistance means of measuring a combined resistance of the skin of the user and the case of the input device.

Typically, the means for outputting the level of stress can include a real-time display associated with the computer workstation whereupon the attention of the user is immediately drawn to an increase or change in stress levels. Alternatively, or additionally, the output means can include forming a computer readable record of stress levels over time for subsequent review.

The invention in another aspect relates to an interface to enable development of software for an application to make use of the electronic data collected. - 4 -

Brief Description of the Drawings

A preferred embodiment of the present invention will now be described with reference to the drawings in which:

Fig. 1 is a schematic illustration of the preferred embodiment;

Fig. 2 is a enlarged illustration of the mouse of Fig. 1;

Fig. 3 is a schematic block diagram representation of the salient components of the preferred embodiment; and

Fig. 4 is a diagram representing the data processing steps associated with the preferred embodiment.

Detailed Description

Fig. 1 shows a computer system or workstation 1 including a computer module 2 to which is connected a display 3 for outputting display information to a user and a keyboard 4 which acts as an input data entry device operable by the user. A further data entry device shown in Fig. 1 comprises a mouse 5 connected to the computer module 2 via a connection 7. The computer module 2 also includes a loudspeaker 6.

As seen in Fig. 2, the mouse 5 comprises a body casing 8 shaped for holding by the hand of the user and includes a number of buttons 9 and 10 manipulable by the fingers of the user to provide data input to the computer module 2. Traditionally, persons using mouse devices rest the palm of the hand on a surface 11 of the body casing 8 thereby enabling the tips of their fingers to manipulate the buttons 9 and/or 10.

In the preferred embodiment, a number of electrical contacts 12, 13 and 14, not necessarily visible, are arranged on respective ones of the buttons 9 and 10 and the surface 11. The electrical contacts 12,13,14 are configured to create an electrical circuit between the palm and the fingers during normal use of the mouse 5. In this manner, when for example the user clicks on the button 9, an electrical circuit is formed between the contacts 12 and 14 thus allowing an electrical current to flow therebetween and through the hand of the user. Having manipulated the mouse 5 in this - 5 -

or another pre-defined manner, the level of electrical current is then able to be determined giving an indication of the specific skin resistance of the user.

It is desirable to provide a conductive paint over the surface of the mouse casing, to reduce the resistance in parallel with the current flow through the hand of the user as described above.

A conductive paint on the surface of the input device casing 8 provides conduction over the input device. The characteristics of the design of the paint together with the internally stored circuit board are such as to provide isolation internally from the high voltage shunting electrode (the casing is acting as this electrode). This electrode shunts high voltage resulting from the current flow from the hand of the user as described above. The design of this isolation prevents electrical damage which would otherwise be caused by electromagnetic inductance.

Referring to Fig. 3, the mouse 5 is shown schematically with the surface contacts 12, 13 and 14 each being connected, via connection 16 to a galvanic skin resistance machine 17. The machine 17 is an electronic device configured to provide an output 18 proportional to the skin resistance of the user.

As seen in Fig. 3, the galvanic skin resistance output 18 is connected to modulation input of a pulse width modulation (PWM) device 19, which is also input with an oscillatory signal provided from a voltage controlled oscillator (VCO) 20. In this manner, the actual value of galvanic skin resistance measured by the machine 17 is used to modulate the pulse width of the oscillatory signal output from the VCO 20.

As seen in Fig. 3, the mouse 5 also includes mouse position circuits 15 well known to those skilled in the art, that are also coupled via the cable 7 to the computer module 2.

As further seen in Fig. 3, the cable 7 connects via a plug 22 to a socket 23 of the computer module 2. The output of the PWM 21 is coupled to unused wire circuits present in the cable 7 for connection to the computer module 2. The signals derived from the mouse 5 are buffered to the computer module 2 via an input/output (I/O) device 24 which typically provides a number of interrupt requests (IRQ1 RQ2) to a - 6 -

controlling microprocessor 25. In this embodiment, IRQ1 may represent signals derived from the mouse position circuits 15 and IRQ2 may represent signals derived from the PWM 19 including representative values of galvanic skin resistance.

The microprocessor 25 is connected to a memory unit 29 which may, for example, include hard disc and semi-conductor memory components and, which includes an application program 30 and a log file 31. A clock 28 is also supplied to the microprocessor 25 to assist the operation thereof. As also illustrated, the microprocessor 25 includes two outputs, one to the loudspeaker 6 for the sounding of various alarms and the like and another to the display 3, better seen in Fig. 1.

The microprocessor 25 is configured to implement the application program 30 in order to service interrupt requests derived from the galvanic skin resistant circuits formed within the mouse 5.

Fig. 4 provides a schematic flowchart of various computer implemented steps 40, contained within the application program 30.

At a first step 41, an interrupt is received from the I/O device 24 and assessed by step 42 as to whether or not it is a valid interrupt. For example, a rising edge value on the interrupt line may be used to start a clock 43 and a falling edge of the interrupt used to stop the clock 43. In this manner, the pulse width modulation of the oscillatory signal by the galvanic skin resistance is converted into a computer readable number based on particular number of clock cycles counted by the counter 43, input with clock pulses from the clock 28. For high levels of accuracy, the clock 28 typically operates at a substantially higher frequency than that of the VCO 20. The output of the counter 43 represents a measured resistance 44 at the surface of the mouse 5. This measured resistance 44 is required to be corrected for any intrinsic resistance in the casing 8 of the mouse 5. That intrinsic resistance is represented by a constant 45 which is subtracted in step 46 from the measured resistance 44. A subtraction reveals an actual value of skin resistance 47. The skin resistance 47 is then supplied to a stress determining step 48 where the skin resistance 47 is compared with a number of predetermined levels of stress 49. In this particular embodiment, four levels of stress are indicated, those being "undetectable", "low", "moderate", and "high". The determining step assesses within which range of the levels the skin resistance falls and outputs a stress level 50 indicative of the level of stress at that particular time of the user of the computer system 1. The stress level 50 can be immediately output in realtime via step 51 to the user. For example, this may entail causing the production of a display of characters, such as those shown at 55 in Fig. 1, on the computer display screen 3. In this fashion, the user of the computer system 1 is immediately appraised as their level of stress and then may personally take action to compensate for those levels of stress. Alternatively, the real-time output can be via the computer loudspeaker 6 which can sound a predetermined style of alarm interpretable by the user as indicative of the level of stress. This alarm may be, for example, various tones or pulses at different amplitude levels.

The stress level output 50 can also be provided to various data logging procedures 52 which provide an ongoing record of the level of stress of the user. As shown, the data logging procedures 52 include a step 53 for determining a cumulative average of stress levels over a period of time established by a timer 54. For example, the period of time may be ten minutes and various measured stress values over that ten minute period averaged by the step 53. At the end of the period, the average stress value is output to the data log file 31 together with information typically including the date, time of day, and an identification number of the computer system 1. In this manner, the data log file 31 can be subsequently reviewed to assess a change in levels of stress over time for the particular user or users of the computer system 1.

The foregoing describes only one embodiment of the present invention and modifications, obvious to those skilled in the art, can be made thereto without departing from the scope of the present invention. For example, a specific alternative application of this technology may include the incorporation of the galvanic skin resistance contacts in the steering wheel of a motor vehicle. In this manner, similar circuits such as those shown in Fig. 3 (omitting the mouse position circuits) can be used to assess the level of stress of the driver of the motor vehicle. Again, stress could be output in real-time for review by the driver and/or recorded in a data log file on subsequently examination. Such an arrangement may highly advantageous for drivers of public transport utilities, such as buses and trains. For example, such examination can reveal not only the level of stress experienced by the driver, but also the period the driver was actively driving. A similar situation exists in office environments where the productivity of workers (eg. word processing operators) can be monitored by a local area network interrogating periodically (eg. daily) the data log file for any one computer terminal. In such situations, the monitoring can not only be taken at the mouse, but also at the computer keyboard via an often used key (eg. spacebar, return enter).

Another specific alternate application of this technology can include the incorporation of the galvanic skin resistance contacts of a handset of a telephone. In this manner, similar circuits such as those shown in Fig. 3 (omitting the mouse position circuits) can be used to access the level of stress of the telephone user.

The applications described can also be activated by the Internet, especially as its developments expand in the field of voice transmission, either conventionally or in wireless mode or other wireless applications. This can be seen from the dotted connection 61 in Fig. 3 which provides data transfer between a Universal Asynchronous Receiver Transmitter (UART) 62 to a load area network (LAN) or the Internet 60.

Claims

CLAIMS:

1. A system for monitoring stress in a biological entity, the entity being in at least occasional physical contact with an apparatus, said system comprising: detecting means configured within the apparatus for detecting a state of the entity in contact with the apparatus; processing means for processing the detected state, to assess a relative level of stress in the entity; and output means for outputting the relative level of stress of the entity.

2. A system as claimed in claim 1, wherein said detecting means includes two or more galvanic skin resistance contacts arranged upon the apparatus, to detect at least a resistance state of said entity in physical contact between each of said contacts.

3. A system as claimed in claim 2, wherein said processing means assesses said relative level of stress by subtracting a known value of resistance of said apparatus between said contacts, from a total resistance measurement taken between each of said contacts.

4. A system as claimed in any one of the preceding claims, wherein said output means is operable in real time in relation to said detecting by said detecting means.

5. A system as claimed in any one of the preceding claims, wherein said output means includes an audio alarm arranged to sound whenever said relative level of stress reaches a pre-determined value.

6. A system as claimed in any one of the preceding claims, wherein said output means includes a data logging arrangement for recording a duration of contact of the entity with the apparatus, and/or a cumulative average relative stress level of the entity over a pre-determined period of time.

7. A system as claimed in any one of the preceding claims, wherein said apparatus is a mouse.

8. A system as claimed in any one of the preceding claims, wherein said apparatus is a joystick.

9. A system as claimed in any one of the preceding claims, wherein said apparatus is a keyboard.

10. A system as claimed in any one of the preceding claims, wherein the apparatus is a motor vehicle steering device .

11. A stress monitoring system comprising: a computer work station operable by a user, said work station including an input entry device being manipulable by the user; a skin resistance measurement means arranged in said data entry device for measuring at least a skin resistance of the user; processing means associated with said skin resistance measurement means, for interpreting at least the measured skin resistance of the user in relation to a predetermined value, to establish a level of stress of the user; and output means for outputting the established level of stress of the user.

12. A system as claimed in claim 11, wherein the input device is a mouse and said skin resistance measurement means includes at least two conductive electrical contacts for measuring at least, a galvanic skin resistance of the user, each of said contacts being respectively located to be contactable with a finger and a palm of the user, respectively.

13. A system as claimed in claim 11 wherein the input device is a joystick and said skin resistance measurement means includes two or more galvanic skin resistance contacts each being arranged to make contact with different regions of a human operator's hand.

14. A system as claimed in any one of claims 11 to 13, wherein said skin resistance measurement means, said processing means and said output means are operable in a real time, to alert the user of the need to take action to reduce the established level of stress.

15. A system as claimed in any one of claims 11 to 14, wherein said output means is arranged to display a visual signal to indicate that said established level of stress is of a value which is undetectable, low, moderate or high.

16. A system as claimed in any one of claims 11 to 15, wherein said output means further includes a data logging arrangement for providing a record of said level of stress level the user over a predetermined period of time.

17. A method for determining a stress level of a user of a computer workstation, said method comprising the steps of: providing at least two galvanic skin resistance contacts on user manipulatable portions of a data input device of the workstation, measuring a resistance between said contacts whenever said data input device is manipulated by the user in a pre-defined manner, and processing said measured resistance to establish a relative stress level of the user.

18. A mouse pointing device comprising: at least two galvanic skin resistance contacts, each being located to be contactable with a single hand of a user of said pointing device; and a conversion device to provide an output signal from said pointing device, corresponding to a biological resistance between each of the contacts.

19. A system for determining a stress level of a user of a computer workstation, said system comprising: a mouse pointing device associated with the workstation, said mouse pointing device having at least two conductive electrical contacts exposed at a surface thereof and being arranged to enable a closed circuit with a hand of the user to be made whenever said pointing device is manipulated by the user in a pre-determined manner, each of said contacts being connected to an input of a galvanic resistance measuring device which provides an electrical output signal in accordance with a connected resistance at said input, said electrical output signal being in turn connected to an input of a modulating device which provides an electrical pulsed output signal of varying frequency as a function of said electrical output signal, a processor associated with the workstation for executing a software application program including a subroutine which is called whenever said closed circuit is enabled, said subroutine including a calculation of an actual skin resistance value and a procedure for providing a message on a display associated with the workstation, wherein said calculation includes a subtraction of a reference value of resistance which corresponds to a resistance of the contacts when said closed circuit is not enabled, from said measured value.