Method and device for measuring stress

• US 7,160,253 B2
• Filed: 10/10/2003
• Issued: 01/09/2007
• Est. Priority Date: 11/08/2002
• Status: Active Grant

• Current Assignee: Polar Electro Oy
• Original Assignee: Polar Electro Oy
• Inventors: Nissila, Seppo
• Primary Examiner(s): Marmor, II; Charles A
• Assistant Examiner(s): Toth; Karen E
• Application Number:
  US10/683,450
• Publication Number:
  US 20040111036A1
• Time in Patent Office: 1,187 Days
• Field of Search: 600/509, 600/322, 600/323, 600500-503
• US Class Current: 600/500
• CPC Class Codes: A61B 5/0006 ECG or EEG signals
• CPC Class Codes: A61B 5/0245 by using sensing means generating electric signals, i.e. ECG signals
• CPC Class Codes: A61B 5/16 Devices for psychotechnics using teaching or educational appliances G09B1/00 - G09B7/00; Testing reaction times ; Devices for evaluating the psychological state
• CPC Class Codes: A61B 5/318 Heart-related electrical modalities, e.g. electrocardiography [ECG]
• CPC Class Codes: A61B 5/329 Load diagnosis, e.g. cardiac stress tests
• CPC Class Codes: A61B 5/33 specially adapted for cooperation with other devices
• CPC Class Codes: A61B 5/681 Wristwatch-type devices
• CPC Class Codes: A61B 5/6887 mounted on external non-worn devices, e.g. non-medical devices

Abstract

The invention relates to a method and an electronic device for implementing the method for measuring mental load. The electronic device generates at least two different cognitively loading tasks for the person participating in the measurement, the first task determining a reference level and at least one other task determining the loading capacity level. The electronic device determines the pulse parameters of the person participating in the measurement during the cognitively loading tasks. The electronic device also compares the pulse parameters during the different tasks with each other. Finally, the electronic device generates a value descriptive of the mental load of the person participating in the measurement on the basis of the comparison of the pulse parameters.

Claims

1. A method of measuring mental load, the method comprising:

measuring, by an electronic device, at least one pulse parameter;

generating, by the electronic device, at least two different cognitively loading tasks for the person participating in the measurement, the first task determining a reference level and at least one other task determining the loading capacity level;

determining, by the electronic device, at least two pulse parameters related to the at least two different cognitively loading tasks for the person participating in the measurement;

comparing, by the electronic device, the pulse parameters during the different tasks with each other; and

generating, by the electronic device, a value descriptive of the mental load of the person participating in the measurement on the basis of the comparison of the pulse parameters, the first task used to determine the reference level being based on reflexive action and the at least one other task used to determine the loading capacity level being based on the use of memory.

2. A method as claimed in claim 1, the method further comprising measuring the heart rate variation as the pulse parameter.

5. A method as claimed in claim 1, the method further comprising seeking for a task loading capacity that keeps the number of errors performed by the person participating in the measurement within the desired limits during the tasks.

8. A method as claimed in claim 1, the method further comprising loading cognitively the person being measured by a receiver unit of a heart rate monitor and generating a value descriptive of the mental load of the person participating in the measurement on the basis of a comparison of the pulse parameters.

9. A method as claimed in claim 1, the method further comprising loading, by the means for loading of the electronic device, the person being measured with at least two different cognitively loading tasks, and

generating, by the receiver unit of the heart rate monitor, a value descriptive of the mental load of the person participating in the measurement on the basis of a comparison of the pulse parameters.

3. A method of measuring mental load, the method comprising:

measuring, by an electronic device, at least one pulse parameter;

generating, by the electronic device, at least two different cognitively loading tasks for the person participating in the measurement, the first task determining a reference level and at least one other task determining the loading capacity level;

determining, by the electronic device, at least two pulse parameters related to the at least two different cognitively loading tasks for the person participating in the measurement;

comparing, by the electronic device, the pulse parameters during the different tasks with each other;

generating, by the electronic device, a value descriptive of the mental load of the person participating in the measurement on the basis of the comparison of the pulse parameters; and

measuring the ratio of the heart rate variation to the heart beat rate as the pulse parameter.

4. A method of measuring mental load, the method comprising:

measuring, by an electronic device, at least one pulse parameter;

generating, by the electronic device, at least two different cognitively loading tasks for the person participating in the measurement, the first task determining a reference level and at least one other task determining the loading capacity level;

determining, by the electronic device, at least two pulse parameters related to the at least two different cognitively loading tasks for the person participating in the measurement;

comparing, by the electronic device, the pulse parameters during the different tasks with each other;

generating, by the electronic device, a value descriptive of the mental load of the person participating in the measurement on the basis of the comparison of the pulse parameters; and

using two cognitively loading tasks, the first task used to determine the reference level being an orientation task and the second task used to determine the loading capacity level being a Stroop task.

6. A method of measuring mental load, the method comprising:

measuring, by an electronic device, at least one pulse parameter;

generating, by the electronic device, at least two different cognitively loading tasks for the person participating in the measurement, the first task determining a reference level and at least one other task determining the loading capacity level;

determining, by the electronic device, at least two pulse parameters related to the at least two different cognitively loading tasks for the person participating in the measurement;

comparing, by the electronic device, the pulse parameters during the different tasks with each other;

generating, by the electronic device, a value descriptive of the mental load of the person participating in the measurement on the basis of the comparison of the pulse parameters; and

measuring, before performance of the cognitive tasks, an initial level associated with rest, and, after the tasks, a final level associated with rest such that the person participating in the measurement is quietly in position during the measurement of both the initial level and the final level, and by correcting the measuring result of mental load according to the measured initial level and final level.

7. A method of measuring mental load, the method comprising:

measuring, by an electronic device, at least one pulse parameter;

generating, by the electronic device, at least two different cognitively loading tasks for the person participating in the measurement, the first task determining a reference level and at least one other task determining the loading capacity level;

determining, by the electronic device, at least two pulse parameters related to the at least two different cognitively loading tasks for the person participating in the measurement;

comparing, by the electronic device, the pulse parameters during the different tasks with each other;

generating, by the electronic device, a value descriptive of the mental load of the person participating in the measurement on the basis of the comparison of the pulse parameters; and

measuring the pulse variation during at least one physically loading task and correcting the measuring result of mental load according to the result obtained from at least one physically loading task.

10. An electronic device for measuring mental load, the electronic device comprising:

a heart rate monitor including means for measuring at least one pulse parameter;

means for loading the person to be measured with at least two different cognitively loading tasks, the first task determining a reference level and at least one other task determining the loading capacity level, wherein

the electronic device is arranged to

determine at least two pulse parameters related to the at least two different cognitively loading tasks for the person participating in the measurement,

compare the pulse parameters during the different tasks with each other, and generate a value descriptive of the mental load of the person participating in the measurement on the basis of the comparison of the pulse parameters, the first task used to determine the reference level being based on reflexive action and the at least one other task used to determine the loading capacity level being based on the use of memory.

11. An electronic device as claimed in claim 10, wherein the means for loading the person to be measured with at least two different cognitively loading tasks are part of the heart rate monitor.

12. An electronic device as claimed in claim 10, wherein the electronic device is arranged to measure the heart rate variation as the pulse parameter.

15. An electronic device as claimed in claim 10, wherein the electronic device is arranged to seek for a task loading capacity that keeps the number of errors performed by the person participating in the measurement within the desired limits during the tasks.

18. An electronic device as claimed in claim 10, wherein the electronic device is a heart rate monitor comprising a receiver unit for cognitively loading the person being measured and for generating a value descriptive of the mental load of the person participating in the measurement on the basis of the comparison of the pulse parameters.

19. An electronic device as claimed in claim 10, wherein the electronic device comprises means for cognitively loading the person being measured and a heart rate monitor receiver unit for generating a value descriptive of the mental load of the person participating in the measurement on the basis of the comparison of the pulse parameters.

13. An electronic device for measuring mental load, the electronic device comprising:

a heart rate monitor including means for measuring at least one pulse parameter;

means for loading the person to be measured with at least two different cognitively loading tasks, the first task determining a reference level and at least one other task determining the loading capacity level, wherein

the electronic device is arranged to

determine at least two pulse parameters related to the at least two different cognitively loading tasks for the person participating in the measurement,

compare the pulse parameters during the different tasks with each other, and generate a value descriptive of the mental load of the person participating in the measurement on the basis of the comparison of the pulse parameters, wherein the electronic device is arranged to measure the ratio of the heart rate variation to the heart beat rate as the pulse parameter.

14. An electronic device for measuring mental load, the electronic device comprising:

a heart rate monitor including means for measuring at least one pulse parameter;

means for loading the person to be measured with at least two different cognitively loading tasks, the first task determining a reference level and at least one other task determining the loading capacity level, wherein

the electronic device is arranged to

determine at least two pulse parameters related to the at least two different cognitively loading tasks for the person participating in the measurement,

compare the pulse parameters during the different tasks with each other, and generate a value descriptive of the mental load of the person participating in the measurement on the basis of the comparison of the pulse parameters, wherein the first task used to determine the reference level is an orientation task and the at least one other task used to determine the loading capacity level is a Stroop task.

16. An electronic device for measuring mental load, the electronic device comprising:

a heart rate monitor including means for measuring at least one pulse parameter;

means for loading the person to be measured with at least two different cognitively loading tasks, the first task determining a reference level and at least one other task determining the loading capacity level, wherein

the electronic device is arranged to

determine at least two pulse parameters related to the at least two different cognitively loading tasks for the person participating in the measurement,

compare the pulse parameters during the different tasks with each other, and generate a value descriptive of the mental load of the person participating in the measurement on the basis of the comparison of the pulse parameters, wherein the electronic device is arranged to measure an initial level associated with rest prior to performing the tasks, and a final level associated with rest after the tasks such that the person participating in the measurement is quietly in position during the rest, and to correct the measuring result of mental load according to the measured initial level and final level.

17. An electronic device for measuring mental load, the electronic device comprising:

a heart rate monitor including means for measuring at least one pulse parameter;

means for loading the person to be measured with at least two different cognitively loading tasks, the first task determining a reference level and at least one other task determining the loading capacity level, wherein

the electronic device is arranged to

determine at least two pulse parameters related to the at least two different cognitively loading tasks for the person participating in the measurement,

compare the pulse parameters during the different tasks with each other, and generate a value descriptive of the mental load of the person participating in the measurement on the basis of the comparison of the pulse parameters, wherein the electronic device is further arranged to measure the pulse variation during at least one physically loading task and by correcting the measuring result of mental load according to the result obtained from the physically loading task.