Psychological state assessment device, psychological state assessment method

• US 20050154322A1
• Filed: 01/11/2005
• Published: 07/14/2005
• Est. Priority Date: 01/14/2004
• Status: Active Grant

• Current Assignee: National Institute of Information and Communications Technology
• Original Assignee: National Institute of Information and Communications Technology
• Inventors: Eda, Hideo, Sugai, Katsuo, Maesako, Takanori, Kuroda, Yasufumi
• Granted Patent: US 7,231,240 B2
• Time in Patent Office: Days
• US Class Current: 600/504
• CPC Class Codes: A61B 5/14553 specially adapted for cerebral tissue
• 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 5/6814 Head

Abstract

In order to offer a new and useful device in being able to objectively assess the psychological state when a subject performs an assignment, a psychological state assessment device is configured to irradiate a specified measurement site in the brain of a subject with near infrared light of a specified wavelength, to obtain time change data indicating time change data for the amount of blood and/or amount of blood components respectively while performing a task and while at rest, and to assess the psychological state of the subject while performing the assignment based on time change data during the rest period in comparison with time change data while performing the task.

Claims

1. A psychological state assessment device which has a subject perform an assignment that comprises multiple tasks and that sets up a rest, a time during which a task is not given, between a specified task and the following task, and which assesses the psychological state when performing the assignment,

comprising:

a measurement unit that detects specified parameter signals having a correlation to the amount of blood and/or the amount of blood components in a specified measurement site in the brain of the aforementioned subject, and measures the intensity of the parameter signals;

a calculator that calculates the amount of blood and/or amount of blood components based on the parameter signal intensities that the measurement unit measures;

a time change data generator that generates time change data indicating the time changes for the amount of blood and/or the amount of blood components when performing a task and when resting respectively by acquiring sequentially over time the amount of blood and/or the amount of blood components that the calculator calculates; and

an output unit that outputs such that a distinction can be made between time change data while performing a task and time change data while at rest, both of which are generated by the time sequence data generator, and also outputs such that the time change data during a specified rest can be compared with time change data while performing the immediately prior and immediately following tasks; and

configured such that the psychological state of the subject when performing the assignment is assessed based on the aforementioned time change data while at rest.

2. The psychological state assessment device according to claim 1 wherein the aforementioned calculator calculates a baseline corrected amount of blood and/or amount of blood components when performing a task and when resting respectively, based on the parameter signal intensities measured by the aforementioned measurement unit during performance of the task and the parameter signal intensities measured when resting.

3. The psychological state assessment device according to claim 2 wherein the aforementioned calculator calculates the aforementioned baseline corrected amount of blood and/or amount of blood components as the amount of blood and/or the amount of blood components in which baselines are subtracted from the value of the amount of blood and/or the amount of blood components calculated by specified computations based on the parameter signal intensities;

and in relation to the calculated values of the amount of blood and/or the amount of blood components when performing a task, the value of the amount of blood and/or the amount of blood components at the initial time the task is performed is taken to be the baseline, and in relation to the calculated values of the amount of blood and/or the amount of blood components while resting, the value of the amount of blood and/or the amount of blood components at the initial point of rest is taken to be the baseline.

4. The psychological state assessment device according to claim 1 wherein the aforementioned measurement unit irradiates a specified measurement site of the brain with near infrared light of a specified wavelength and measures the intensity of the exiting light, that is the aforementioned parameter signals, that exits from the aforementioned measurement site based on the irradiated light;

and the aforementioned calculator calculates the amount of blood and/or the amount of blood components based on the intensity of the aforementioned exiting light.

5. The psychological state assessment device according to claim 2

the aforementioned measurement unit irradiates a specified measurement site of the brain of the subject with near infrared light of a specified wavelength, and measures the intensity of the exiting light, that is the aforementioned parameter signals, that exits from the aforementioned measurement site based on the intensity of the aforementioned exiting light;

and

the aforementioned calculator comprises;

a light absorbance time change data generator that calculates the light absorbance of a measurement site at a specified wavelength from the intensity of the exiting light measured by the measurement unit, and generates light absorbance time change data indicating the time changes of the light absorbance;

a light absorbance time change data correction unit that conducts baseline correction of the light absorbance time change data that the light absorbance time change data generator generates respectively while performing a task and while at rest; and

a blood amount and/or a blood components amount calculator that calculates the amount of blood and/or the amount of blood components from the light absorbance time change data corrected by the light absorbance time change data correction unit; and

calculates the baseline corrected amount of blood and/or amount of blood components.

6. The psychological state assessment device according to claim 4 wherein the aforementioned measurement unit is a 1-channel device.

7. The psychological state assessment device according to claim 5 wherein the aforementioned measurement unit is a 1-channel device.

8. The psychological state assessment device according to claim 1 wherein the aforementioned calculator calculates the amount of oxyHb and amount of deoxyHb, as the amount of the blood and/or amount of the blood components, in the blood at the aforementioned measurement site.

9. The psychological state assessment device according to claim 1 wherein the aforementioned output unit outputs the waveforms of the time change data while performing a task and while at rest.

10. A psychological state assessment method that has a subject perform an assignment that comprises multiple tasks and that sets up a rest, a time during which a task is not given, between a specified task and the following task, and assesses the psychological state while performing the assignment wherein

time change data when resting is extracted by measuring the intensity of specified parameter signals having a correlation to the amount of blood and/or the amount of blood components of a specified measurement site of the brain of the aforementioned subject, by calculating the amount of blood and/or the amount of blood components based on the parameter signal intensity, and by generating time change data indicating the time changes in the amount of blood and/or the amount of blood components while performing a task and while at rest respectively;

and

the psychological state of the subject when performing the assignment is assessed based on the time change data when resting.

11. A method of measuring brain activity during predetermined assigned tasks to be performed by a subject, comprising:

applying electromagnetic radiation and a magnetic field to provide a composite image of a brain;

selecting a measurement site appropriate to measure oxyHb and deoxyHb from the composite image;

applying sensors to the measurement site of the subject to enable measurement of the amount of oxyHb and deoxyHb;

having the subject perform a test cycle of predetermined assigned tasks with a predetermined rest period provided between the tasks;

measure the oxyHb and deoxyHb during the assigned tasks and the rest period of the test cycle;

calculate changes in the oxyHb and deoxyHb during the test cycle;

calculating a baseline correction value from the changes in oxyHb and deoxyHb based on the relative changes in value from the rest period and the assigned tasks; and

apply the baseline correction value to the measured oxyHb and deoxyHb to determine a psychological state of the subject.