Living body light measuring device

• US 20040171919A1
• Filed: 01/23/2004
• Published: 09/02/2004
• Est. Priority Date: 02/28/2003
• Status: Active Grant

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Yamamoto, Tsuyoshi, Maki, Atsushi
• Granted Patent: US 7,139,597 B2
• Time in Patent Office: Days
• US Class Current: 600/310
• CPC Class Codes: A61B 2562/0233 Special features of optical sensors or probes classified in A61B5/00
• CPC Class Codes: A61B 2562/046 in a matrix array
• CPC Class Codes: A61B 5/0261 using optical means, e.g. infrared light
• 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 5/7207 of noise induced by motion artifacts

Abstract

There has been no device for measuring changes in Hb concentrations associated with activities of the cerebral function of an infant or subject prone to movement during measurement. Removing and reducing any influences of body movement is needed. In the present invention, light is irradiated on the subject'"'"'s head, and changes in Hb concentrations associated with activities of the cerebral function are measured from scattered light which has passed through the head. From this blood circulation movement, a parameter is inputted arbitrarily to judge the body movement component, and feed-back is applied to a stimulus device for giving a stimulus to the subject.

Claims

1. A living body light measuring device comprising:

a light irradiating source for irradiating light into a living body which is a subject of study;

a light condensing detector for condensing living body passage light for detection, when light irradiated by said light irradiating source passes through the interior of said living body,

a stimulus device from which a stimulus is intermittently applied to said subject;

a noise detection device so that if it is detected that said living body passage light detected contains noise associated with body movement of said subject, a signal derived from said living body passage light detected in an arbitrary period is excluded from a measured signal by a signal processor.

4. The living body light measuring device according to claim 1, further comprising:

a band pass filter for causing said measured signal to pass through a predetermined frequency band,

a display screen for inputting a parameter which sets said frequency band of said band pass filter, and where on said display screen, a frequency characteristic of said signal is also displayed at the same time when said band of said band pass filter is set to aid in setting the frequency band of the band pass filter.

5. The living body light measuring device according to claim 4, wherein on said display screen, a signal of a time domain is displayed at the same time.

6. The living body light measuring device according to claim 5, wherein said parameter inputted on said display screen and said display of said signal of the time domain are in synchronization with each other in real time.

7. The living body light measuring device according to claim 1, wherein from an amount of change in an arbitrary time interval in a time domain of a value corresponding to an amount of change in hemoglobin concentration or a change in hemoglobin concentration of said measured signal measured within unit time, a noise level associated with body movement which a signal measured is determined.

8. The living body light measuring device according to claim 7, further comprising:

a criterion value parameter for judging a noise level associated with body movement present in said signal measured;

a graph for representing a characteristic of said criterion value parameter; and

a display screen for displaying a statistic of said characteristic.

9. The living body light measuring device according to claim 7, further comprising:

a display screen for setting a criterion value for judging a noise level associated with body movement present in said signal measured;

and a display screen for displaying a signal graph in the time domain in which said criterion value is reflected in real time.

2. A living body light measuring device comprising:

a light irradiating source for irradiating light into a living body which is a subject of study;

a light condensing detector for condensing living body passage light for detection when light irradiated by said light irradiating source passes through the interior of said living body,

a stimulus device wherein a stimulus is intermittently provided to said subject;

a noise detector from which on the basis of detected noise associated with body movement of said subject in said living body passage light detected, a direction is given to the stimulus device to control a stop and start of the stimulus applied and to control a number of times of said stimulus to be given to said subject which has been programmed in advance and said stimulus application is changed based on the movement of the subject.

10. The living body light measuring device according to claim 2, further comprising:

a band pass filter for causing said measured signal to pass through a predetermined frequency band,

a display screen for inputting a parameter which sets said frequency band of said band pass filter, and where on said display screen, a frequency characteristic of said signal is also displayed at the same time when said band of said band pass filter is set to aid in setting the frequency band of the band pass filter.

12. The living body light measuring device according to claim 2, wherein from an amount of change in an arbitrary time interval in a time domain of a value corresponding to an amount of change in hemoglobin concentration or a change in hemoglobin concentration of said measured signal measured within unit time, a noise level associated with body movement which a signal measured is determined.

14. The living body light measuring device according to claim 12, further comprising:

a criterion value parameter for judging a noise level associated with body movement present in said signal measured;

a graph for representing a characteristic of said criterion value parameter; and

a display screen for displaying a statistic of said characteristic.

3. A living body light measuring device comprising:

a light irradiating source for irradiating light into a living body which is a subject of study;

a light condensing detector for condensing living body passage light to be obtained, for detection, when light irradiated by said light irradiating source passes through the interior of said living body,

a stimulus device from which a stimulus is intermittently given to said subject, and on the basis of noise associated with body movement of said subject in said living body passage light detected by said detector a number of times of a stimulus to be given to said subject which has been programmed in advance will be changed.

11. The living body light measuring device according to claim 3, further comprising:

a band pass filter for causing said measured signal to pass through a predetermined frequency band,

a display screen for inputting a parameter which sets said frequency band of said band pass filter, and where on said display screen, a frequency characteristic of said signal is also displayed at the same time when said band of said band pass filter is set to aid in setting the frequency band of the band pass filter.

13. The living body light measuring device according to claim 3, wherein from an amount of change in an arbitrary time interval in a time domain of a value corresponding to an amount of change in hemoglobin concentration or a change in hemoglobin concentration of said measured signal measured within unit time, a noise level associated with body movement which a signal measured is determined.

15. The living body light measuring device according to claim 13, further comprising:

a display screen for setting a criterion value for judging a noise level associated with body movement present in said signal measured;

and a display screen for displaying a signal graph in the time domain in which said criterion value is reflected in real time.

16. A method for controlling the timing of sound stimulus in an optical imaging system used to image a living body of a subject under study comprising:

setting a predetermined number of sound stimulus applications to be applied over a time period to a subject sufficient to produce a measurement signal from optical radiation applied to the subject which is directed into the subject'"'"'s body and detected by a detector and which shows the subject'"'"'s reaction to the sound stimulus;

detecting in a detector whether said subject'"'"'s body makes a movement by detecting noise in said measurement signal;

stopping the stimulus if body movement noise is detected in the measurement signal by sending a discontinue signal of the sound stimulus under execution currently; and

sending a signal for setting the time of the next sound stimulus to be transmitted to a stimulus control device;

wherein a time period between termination of each sound stimulus and the next sound stimulus presented is adjusted to be a minimal time period to provide a movement free measurement signal in a minimum amount of time including the predetermined number of sound stimulus applications to be applied because no useless sound stimulus time is expended when the subject is moving and is not stabilized.