U.S. patent application number 12/594200 was filed with the patent office on 2010-11-25 for determining stress level based on the performance of the person in a game or puzzle.
This patent application is currently assigned to KONINKLIJKE PHILIPS ELECTRONICS N.V.. Invention is credited to Petronella Hendrika Pelgrim, Privender Kaur Saini, Wilhelmus Johannes Joseph Stut, Evert Jan Van Loenen, Richard Vdovjak, Frank Wartena, Joanne Henriette Monique Westerink.
Application Number | 20100295244 12/594200 |
Document ID | / |
Family ID | 39669866 |
Filed Date | 2010-11-25 |
United States Patent
Application |
20100295244 |
Kind Code |
A1 |
Stut; Wilhelmus Johannes Joseph ;
et al. |
November 25, 2010 |
DETERMINING STRESS LEVEL BASED ON THE PERFORMANCE OF THE PERSON IN
A GAME OR PUZZLE
Abstract
A system and a method are described for determining a stress
level of a person based on the performance of the person in a game
or puzzle. First, in a calibration phase the person is asked to
judge his/her currently experienced stress level (120) and the
person is asked to play (130) a game or puzzle resulting in a
certain performance score. Subsequently in this calibration phase,
the system links (150) the indicated stress level and the
performance score. By repeating these steps a number of times, the
system builds a table linking game performance scores and stress
levels. The calibration phase will be executed initially and once
every while to keep the system calibrated. Subsequently, in an
operational phase, the person is occasionally asked (220) to play a
game. Then, based on the current performance score and on the table
assembled in the calibration phase, the system determines (250) the
current stress level. Depending on the level, and on the period
over which the level continues, the system may undertake some
action (260), such as alerting the person or providing
distraction.
Inventors: |
Stut; Wilhelmus Johannes
Joseph; (Eindhoven, NL) ; Pelgrim; Petronella
Hendrika; (Eindhoven, NL) ; Saini; Privender
Kaur; (Eindhoven, NL) ; Vdovjak; Richard;
(Eindhoven, NL) ; Westerink; Joanne Henriette
Monique; (Eindhoven, NL) ; Van Loenen; Evert Jan;
(Eindhoven, NL) ; Wartena; Frank; (Eindhoven,
NL) |
Correspondence
Address: |
PHILIPS INTELLECTUAL PROPERTY & STANDARDS
P.O. BOX 3001
BRIARCLIFF MANOR
NY
10510
US
|
Assignee: |
KONINKLIJKE PHILIPS ELECTRONICS
N.V.
EINDHOVEN
NL
|
Family ID: |
39669866 |
Appl. No.: |
12/594200 |
Filed: |
April 2, 2008 |
PCT Filed: |
April 2, 2008 |
PCT NO: |
PCT/IB2008/051236 |
371 Date: |
October 1, 2009 |
Current U.S.
Class: |
273/153R ;
273/460 |
Current CPC
Class: |
A61B 5/16 20130101; A61B
5/165 20130101; A61B 5/4884 20130101 |
Class at
Publication: |
273/153.R ;
273/460 |
International
Class: |
A63F 9/00 20060101
A63F009/00 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 4, 2007 |
EP |
07105593.3 |
Claims
1. System for determining a stress level of a person based on the
performance of the person in a game or puzzle, wherein the system
is adapted for: in a calibration phase: executing the steps of
measuring (140) the performance of the person in a game or puzzle
and storing (150) information linking the performance to a given
stress level of the person when playing the game or puzzle, and in
an operational phase, executing the steps of measuring (230) the
performance of the person in the game or puzzle, again and
determining (250) the stress level of the person based on the
measured performance and the information stored in the calibration
phase.
2. System for determining a stress level according to claim 1,
wherein the system is adapted for, in the calibration phase,
executing the steps of measuring (140) the performance of the
person in the game or puzzle and storing (150) information linking
the performance to a given stress level of the person a plurality
of times.
3. System for determining a stress level according to claim 1,
wherein the system is adapted for receiving (120) an indication of
the person of the given stress level in the calibration phase.
4. System for determining a stress level according to claim 1,
wherein the system is adapted for measuring the given stress level
in the calibration phase.
5. System for determining a stress level according to claim 1,
wherein the system is adapted for executing the calibration phase
initially and repeating it, periodically.
6. System for determining a stress level according to claim 1,
wherein the system is adapted for performing (260) an action
towards the person if the determined stress level in the operation
phase is high.
7. System for determining a stress level according to claim 6,
wherein the system is adapted for performing (260) the action
towards the person if the determined stress level in the operation
phase is high over a period of time.
8. System for determining a stress level according to claim 6,
wherein the action is the generation of an alert.
9. System for determining a stress level according to claim 6,
wherein the action is providing distraction to the person.
10. System for determining a stress level according to claim 1,
wherein in the operational phase the system is adapted for inviting
the person to play the game or puzzle in time slots with a similar
activity level of the person.
11. System for determining a stress level according to claim 10,
wherein in the operational phase the system is adapted for inviting
the person to play the game or puzzle at a similar time of the
day.
12. System for determining a stress level according to claim 1,
wherein the game is a word memory game comprising neutral words and
emotional words.
13. System for determining a stress level according to claim 1,
wherein the game is having the person naming colors in which words
are printed.
14. Method for determining a stress level of a person based on the
performance of the person in a game or puzzle, comprising the
following steps: in a calibration phase: measuring (140) the
performance of the person in a game or puzzle and storing (150)
information linking the performance to a given stress level of the
person when playing the game or puzzle, and in an operational
phase, measuring (230) the performance of the person in the game or
puzzle, again and determining (250) the stress level of the person
based on the measured performance and the information stored in the
calibration phase.
15. A computer program comprising computer program code means
adapted to perform the steps of claim 14, when said program is run
on a computer.
16. A computer program as claimed in claim 15 embodied on a
computer readable medium.
17. A carrier medium carrying the computer program of claim 15.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Technical Field
[0002] The present invention relates to a system, method and
software for determining a stress level of a person.
[0003] 2. Description of Related Art
[0004] Several surveys show that many people suffer from stress at
work. For example, a survey by Northwestern National Life indicates
that 40% of workers report that their job is very or extremely
stressful. A survey by Yale University indicates that 29% of
workers report that they feel quite a bit or extremely stressed at
work. According to Anderson et al, high stress yearly generates a
cost of $136 per employee, making stress very expensive for
employers.
[0005] According to the National Institute for Occupational Safety
and Health (NIOSH, see http://www.cdc.gov/niosh/stresswk.html), job
stress can be defined as the harmful physical and emotional
responses that occur when the requirements of the job do not match
the capabilities, resources, or needs of the worker. Job stress can
lead to poor health and even injury. Common complaints include loss
of concentration, mood and sleep disturbances, upset stomach, and
headache.
[0006] An important way to reduce the costs of stress and to
improve the well-being of people at work is to detect in an early
phase whether a person has stress. When detecting stress in an
early phase, measures can be taken on time, such as solving
stressful working conditions or helping a person to cope with
demanding job conditions.
[0007] Currently there are many ways to measure stress. A first
known approach is to use self-report questionnaires. Still other
known methods include interviews, or observations of a person, such
as delayed reaction times or heightened tendency to procrastinate.
In a more advanced stage the number of mental or physical
complaints can be counted in order to determine the severity of
these complaints.
[0008] According to other known approaches stress is determined by
measuring a physiological parameter of a person. For example,
stress can be measured by determining the level of the hormone
cortisol in the blood. Cortisol is a corticosteroid hormone that is
involved in the response to stress.
[0009] WO2006/105085 A2 discloses measuring a breathing pattern of
a person with a sensor and giving auditory or visual feedback
corresponding to the relaxation pattern of the person.
[0010] The mentioned approaches all have drawbacks for the
person-under-test. First of all, he or she must explicitly do a
test that is not a natural part of his or her daily life. According
to some of the known approaches the person is subjected to tests
that only a professional can do. In some cases this means that the
person-under-test must even go to a laboratory or a professional
infrastructure like a laboratory to be subjected to testing.
Furthermore, at the time of performing the tests the person may
have suffered from stress for a longer time and complaints may have
become severe enough to need actual professional intervention.
[0011] It is an object of the invention to provide a system and
method for determining the stress of a person that may be
integrated in his or her normal routine.
SUMMARY OF THE INVENTION
[0012] This and other objects of the invention are achieved by a
system according to claim 1, a method according to claim 14 and a
computer program according to claim 15. Favorable embodiments are
defined by the dependent claims 2-13 and 16-17.
[0013] According to an aspect of the invention a system is provided
for determining a stress level of a person based on the performance
of the person in a game or puzzle. In a calibration phase the
performance of the person in a game or puzzle is measured and
information is stored linking the performance to a given stress
level of the person when playing the game or puzzle. Subsequently,
in an operational phase, the performance of the person in the game
or puzzle is measured, again. The stress level of the person is
determined based on the measured performance and the information
stored in the calibration phase.
[0014] The game-based test according to the invention is easier
accessible to a person than tests needing professional tools. By
integrating the stress test in a pleasant and normal activity like
playing a game, people are likely to be less disturbed. For this
reason, the test results are likely to better reflect a person's
condition. Furthermore, playing a game not only is a means to
detect the stress level, but at the same time may help to reduce
stress, to relax, to increase concentration, to reduce mental
fatigue, and to make the person's memory function better as is
described in more detail in the co-pending patent application EP
06124905.8. The invention can be applied in any environment where
people suffer from stress. It can be used at home, but also in the
office environment in order to detect and reduce stress and to
improve the mental health of workers. The game-based test according
to the invention preferably is complementary to known tests that
need professional tools.
[0015] Preferably, in the calibration phase the steps of measuring
the performance of the person in the game or puzzle and storing
information linking the performance to a given stress level of the
person are executed a plurality of times. For example, the
calibration phase may last for a month during which the person
repeatedly plays games, for example once a day. The system measures
the person's performance at each game, and relates this to the
given level of experienced stress of the person. In this way the
system can calculate the person's average game performance for each
experienced stress level.
[0016] The system preferably is adapted for receiving an indication
from the person of the given stress level in the calibration phase.
In this way, the given stress level is obtained in a very easy way
without the need of any additional equipment.
[0017] Alternatively, the system is adapted for measuring the given
stress level in the calibration phase. The given stress level may
be measured by measuring a physiological parameter of the person,
which is indicative of stress, in a known way. Examples are the
body temperature or Galvanic Skin Response. Thereto the system
needs to be provided with or connected to suitable sensors.
[0018] Preferably, the system is adapted for executing the
calibration phase initially and repeating it, periodically. The
calibration phase may be repeated every few weeks or months to keep
track of learning and experience effects.
[0019] According to an embodiment the system is adapted for
performing an action towards the person if the determined stress
level in the operation phase is high. Since, according to experts
short-lived or infrequent episodes of stress pose little risk,
preferably the action towards the person is not performed in case
of an incidental high stress measurement but only if the determined
stress level in the operation phase is high over a period of
time.
[0020] The action towards the person may be the generation of an
alert for the person. For example, the system may inform the person
of the continued high stress level and it may be suggested to take
measures or to contact a professional for further tests or
advise.
[0021] Alternatively, the action is providing distraction to the
person. The distraction aims to relax the person. It may be
inviting the person to play a different game which is more relaxing
than the game that is used for stress determination, to show
relaxing pictures or to play relaxing music or to generate certain
scents, etc.
[0022] For reasons of consistency in the operational phase the
system is adapted for inviting the person to play the game or
puzzle in time slots with a similar activity level of the person.
This is preferably a "low stress" time slot because it is easier to
detect a low performance in a "low stress" time slot than in a
"high stress" time slot. The time slots with similar activity level
may be at a similar time of the day, for example right after
lunch.
[0023] The system may use known games to determine the stress or
special games may be designed for this purpose. According to a
preferred embodiment the game is a word memory game comprising
neutral words and emotional words. Research has revealed that in a
normal, i.e. non-stressed population the emotional words should be
recalled better. However, this is not the case for people
experiencing stress. They recall fewer emotional words, whereas
their performance on recall of neutral words is not deterred. So,
the person's performance in this game can be used to determine
his/her stress level.
[0024] According to an alternative embodiment the game is having
the person naming colors in which words are printed. The word list
will be chosen to include "neutral" as well as "highly relevant"
words. These "highly relevant" words should be in the domain of the
"work related stress". In case that the person is stressed the
reaction times for naming the color will be longer for the highly
relevant words.
[0025] According to a further aspect of the invention a method is
provided for determining a stress level of a person based on the
performance of the person in a game or puzzle, comprising the
following steps:
[0026] in a calibration phase: measuring the performance of the
person in a game or puzzle and storing information linking the
performance to a given stress level of the person when playing the
game or puzzle, and
[0027] in an operational phase, measuring the performance of the
person in the game or puzzle, again and determining the stress
level of the person based on the measured performance and the
information stored in the calibration phase.
[0028] Preferably, the method according to the invention is
implemented by means of a computer program.
[0029] These and other aspects of the invention will be apparent
from and elucidated with reference to the embodiments described
hereinafter.
BRIEF DESCRIPTION OF THE DRAWINGS
[0030] The invention will be better understood and its numerous
objects and advantages will become more apparent to those skilled
in the art by reference to the following drawings, in conjunction
with the accompanying specification, in which:
[0031] FIG. 1 shows a flow chart of the steps that are executed
during the calibration phase in an embodiment of the system
according to the invention.
[0032] FIG. 2 shows a flow chart of the steps that are executed
during the operational phase in an embodiment of the system
according to the invention.
[0033] FIG. 3 shows an example of game performance as a function of
time.
[0034] FIG. 4 shows a block diagram of an exemplary embodiment of
the system according to the invention.
[0035] Throughout the figures like reference numerals refer to like
elements.
DETAILED DESCRIPTION OF THE PRESENT INVENTION
[0036] Referring now to FIG. 1, the steps that are executed during
the calibration phase in an embodiment of the system according to
the invention will be described.
[0037] Before the system can determine a person's stress level via
his/her game performance, it should be calibrated. This is due to
the fact that every person performs differently under different
levels of stress. A possible way to calibrate is to let the person
repeatedly play games over a sufficiently long period of time, for
example once a day during a month and to let the user indicate the
amount of stress experienced before the start of each game. The
system measures the person's performance at each game, and relates
this to the amount of experienced stress as indicated by the
person. In this way the system can calculate the person's average
game performance or score for each experienced stress level. For
example, the person reaches an average score of 800 points in the
"no stress" situation, 600 points at "medium stress", and 400
points at "high stress".
[0038] In order to calibrate the system, after the step of
initialization 100, it is determined in step 110 if it is time to
perform a calibration measurement. If it is not, step 110 is
repeated. If it is time for a calibration measurement, in step 120
the person is requested to indicate the amount of stress
experienced before starting to play the game. For example, the
person may be prompted to indicate if he/she has no stress, medium
stress or high stress. Alternatively, the level of stress may be
measured by measuring a physiological parameter of the person,
which is indicative of stress, in a known way. Examples are the
body temperature or Galvanic Skin Response. Thereto the system
needs to be provided with or connected to suitable sensors.
[0039] Thereafter, in step 130 the person plays the game. In step
140 the game performance or score is determined. To enable the
system the measuring of a person's stress level, various game
performance indicators may be used. Depending on the game, the
following performance indicators are useful (but other indicators
may be useful as well): the score (i.e. number of points) in a
game
[0040] the time needed to complete a game
[0041] the level reached in a game
[0042] the number of errors made in a game
[0043] the number of objects (e.g. balls) that the person can deal
with simultaneously
[0044] the speed of objects (e.g. balls) that the person can deal
with
[0045] the percentage of correct answers (in e.g. a crossword
puzzle)
[0046] the time needed to start/enter/continue a game in a set of
alternating games.
[0047] These performance indicators can be used both for
calibrating the system, and for detecting stress in the subsequent
operational phase, that will be described herein after.
[0048] In step 150 the measured performance is linked to the stress
level that the person indicated in step 120 and both these
parameters are stored. In step 160, the system checks if there are
more calibration measurements needed. If this is the case the
system loops back to step 110. If not, the calibration phase is
finished in step 170. In this way, the system builds up a table
linking game performance scores and stress levels.
[0049] Once the system has been calibrated to a person, it can in a
so called operational phase relate the performance of this person
in a game session to his/her calculated average score for each
experienced stress level. This is shown in FIG. 2.
[0050] After initialization (step 200) it is determined in step 210
if it is time to determine the stress level of the person. If this
is the case, the system invites the person to play the same game
that was played during the calibration phase. This game is played
by the person in step 220. After the game the person's performance
is determined (step 230) and stored (step 240). In step 250 it is
determined if an action should be taken towards the person. If the
performance stored in step 240 correspond to medium or high stress
for a longer period of time (e.g. during a week), the system
determines that action should be taken. An example of such a
situation is shown in FIG. 3. FIG. 3 shows the performance (P) as a
function of time (t). Area 310 (the highest performances)
corresponds to scores that were measured during the calibration
period when the person indicated that he/she had no stress. Area
320 corresponds to scores that were been measured during the
calibration period when the person indicated that he/she had medium
stress. Area 330 (the lowest performances) corresponds to scores
that were measured during the calibration period when the person
indicated that he/she had high stress. FIG. 3 shows 8 scores that
were measured in the operational phase, i.e. after the system was
calibrated. The first 4 scores in the upper area indicate that the
person had no stress at these moments. However, the next 4 scores
in the lower area suggest that the person had high stress.
[0051] In step 260 the system may inform the person about his/her
high stress level and may suggest to take measures or to contact a
professional for further tests and advise. Note that the system
need not inform the person about an incidental performance that may
indicate stress. Alternatively or additionally, in step 260 the
system may provide distraction to the person. The distraction aims
to relax the person. For example, the person may be invited to play
a different game which is more relaxing than the game that is used
for stress determination, to show relaxing pictures or to play
relaxing music or to generate certain scents, as is described in
more detail in the co-pending patent application EP 06124905.8.
[0052] In step 270 it is determined if calibration measurement(s)
should be repeated. If this is the case, steps 120-160 of FIG. 1
are executed, again. If not, the system loops back to step 210. The
calibration should be repeated every few weeks or months in order
to keep track of learning and experience effects.
[0053] According to experts and the National Institute for
Occupational Safety and Health (NIOSH), short-lived or infrequent
episodes of stress pose little risk. But when stressful situations
go unresolved, the body is kept in a constant state of activation,
which increases the rate of wear and tear to biological systems. It
therefore appears sufficient to perform the test once a day. For
reasons of consistency, it is preferred to play the game at the
same moment and preferably in a `low stress` time-slot. For
example, the person can be invited to play the game right after
lunch or early in the morning when no meetings are planned. The
reason for this is that it is easier to detect a low score in a
low-stress time-slot than in a high-stress time-slot.
[0054] The person's electronic calendar and/or to do list can be
used by the system to determine the best time for both the
calibration measurements as well as the measurements during the
operational phase. The same calendars can also be used to find high
stress times, which can be interrupted by games to avoid build-up
of stress.
[0055] Any type of game may be used in the system according to the
present invention. However, it is preferred to use games derived
from known psychological tests for the purpose of measuring stress.
These games will be more resistant to factors of boredom or
experience. A different type of game may be used to play in order
to relax, have fun, and provide a mental break from continued
pressure.
[0056] Now, two examples will be described of games that are very
suitable for the stress determination according to the present
invention Stress causes impairments in memory retrieval. A game can
be devised in which people have to learn a list of words that they
have to recall later that day or the next day. This list of words
can be set up such that it contains neutral as well as emotional
words (negative and positive). Neutral words could be words like
window, forest, mountain, buildings, kangaroo, etc. So any word
that is not related to the stressful situation. In case that the
stressful situation is work, emotional words could be: traffic-jam,
computer, deadline, presentation, report, meeting, stress,
colleagues, lunch, coffee-break, etc. So any word that reasonably
is related to work. The human mind protects itself from threats by
a number of mechanisms. One of the mechanisms is selective memory.
In case of remembering words, humans tend to block the words that
arouse negatively, like the emotional words, even when they might
be positive like coffee-break or lunch. In a normal population the
emotional words should be recalled better. However, this is not the
case for people experiencing stress. Fewer emotional words should
be recalled, whereas performance on recall of neutral words should
not be deterred. See, for a more details on the relationship
between stress and memory retrieval "Impaired memory retrieval
after psychosocial stress in healthy young men (2005)" by.
Kuhlmann, S., Piel, M. and Wolf, O. T. Journal of Neuroscience,
25(11). 2977-2982.
[0057] Reaction time measurements will reveal whether people are
experiencing stress. There are many variants to the Stroop task,
and there are a few mechanisms by which it can work to expose
people experiencing stress or not. One such mechanism is the
attentional bias. A Stroop task could be to have the person name
the colors in which words are printed. The word list will be chosen
to include "neutral" as well as "highly relevant" words. These
"highly relevant" words should be in the domain of the
psychopathology, which in the present case is "work related
stress". When a person has a certain pathology, words related to
that pathology momentarily over-arouse that person. When somebody
has overweight and is trying to lose weight, the word `diet` is
going to send a `rush` through his/her body without that person
being able to do anything about it. Similarly, when a person is
stressed chronically, there will be certain words that will send a
surge through his/her mind and momentarily block him/her from doing
anything else, such as naming a color. This can be measured by
reaction-times (in milliseconds). So the same emotional (highly
relevant) and neutral words as above can be used in this Stroop
task. Only in this case the nature of the task will activate a
different mechanism. Reaction times for naming the color will be
longer for highly relevant (emotional) words. For more information
on Stroop tasks, see "The emotional Stroop task and
psychopathology" (1996). Williams, J. M. G., Mathews, A., and
MacLeod, C. Psychological Bulletin. 120(1), July 1996, 3-24. More
variations of the Stroop task can be devised. These tasks can be
easily translated into a game-like format.
[0058] According to a preferred embodiment of the system the test
is implemented on a computer, such as a PC, Xbox, Playstation,
mobile phone, PDA, etc. Since the test is personal, the computer
should have means such that the person can identify him/herself or
should be a personal computer. FIG. 4 illustrates an exemplary
computer system 400 for implementing the steps according to FIG. 1.
It shows a processor 410, a memory 420, a display 430, an input
means 440, which may be a keyboard and a mouse, and communication
means 450. In this exemplary embodiment the processor 410 executes
instructions stored in the memory 420, for executing the steps
shown in FIGS. 1 and 2. The input means 440 are used to control the
game. The communication means 450 can be used for exchanging
information with external systems (e.g. for adding new games). The
display 430 is used to show the game to the person, to inform the
person about his/her game performance, and (if needed) suggest the
person to take measures or to contact a professional for further
tests and advise.
[0059] The invention can be resumed as follows: A system and a
method for determining a stress level of a person based on the
performance of the person in a game or puzzle. First, in a
calibration phase the person is asked to judge his/her currently
experienced stress level and the person is asked to play a game or
puzzle resulting in a certain performance score. Subsequently in
this calibration phase, the system links the indicated stress level
and the performance score. By repeating these steps a number of
times, the system builds a table linking game performance scores
and stress levels. The calibration phase will be executed initially
and once every while to keep the system calibrated.
[0060] Subsequently, in an operational phase, the person is
occasionally asked to play the game. Then, based on the current
performance score and on the table assembled in the calibration
phase, the system determines the current stress level. Depending on
the level, and on the period over which the level continues, the
system may undertake some action, such as alerting the person or
providing distraction.
[0061] As will be recognized by those skilled in the art, the
innovative concepts described in the present application can be
modified and varied over a wide range of applications.
[0062] Accordingly, the scope of patented subject matter should not
be limited to any of the specific exemplary teachings discussed,
but is instead defined by the following claims.
[0063] Any reference signs in the claims shall not be construed as
limiting the scope thereof.
* * * * *
References