Measurement system for living bodies

• US 20040077960A1
• Filed: 06/10/2003
• Published: 04/22/2004
• Est. Priority Date: 10/22/2002
• Status: Active Grant

• Current Assignee: Hitachi, Ltd., Hitachi Medical Corporation (Hitachi, Ltd.)
• Original Assignee: Hitachi, Ltd., Hitachi Medical Corporation (Hitachi, Ltd.)
• Inventors: Maki, Atsushi, Kiguchi, Masashi, Tanaka, Naoki
• Granted Patent: US 7,022,083 B2
• Time in Patent Office: Days
• US Class Current: 600/504
• CPC Class Codes: A61B 5/0086 using infrared radiation
• CPC Class Codes: A61B 5/1455 using optical sensors, e.g. spectral photometrical oximeters
• CPC Class Codes: A61B 5/486 Bio-feedback A61B5/375 takes precedence

Abstract

A satisfactory averaged signal can be obtained with only a small number of repetitions of measurement in the measurement of responses to a stimulus given to a living body. A low-frequency biological fluctuation is extracted and a stimulus is presented to the living body in synchronism with the phase of the extracted fluctuation.

Claims

1. A measurement system for living bodies comprising:

a measurement unit for measuring the internal state of a subject body;

a signal extraction unit for extracting a biological fluctuation component contained in a signal obtained by the measurement unit;

a stimulus timing determination unit for determining the timing of presentation of a stimulus or instruction to the subject body on the basis of the biological fluctuation component extracted by the signal extraction unit;

a stimulus/instruction presentation control unit for controlling the presentation of a stimulus or instruction such that the presentation occurs at the time determined by the stimulus timing determination unit; and

a stimulus/instruction presentation unit for presenting a stimulus or instruction to the subject body in accordance with a control signal from the stimulus/instruction presentation control unit.

2. The measurement system for living bodies according to claim 1, wherein the signal extraction unit extracts a low-frequency component of the signal measured by the measurement unit.

3. The measurement system for living bodies according to claim 2, wherein the low-frequency component is in the range between 0.01 Hz to 0.5 Hz.

4. The measurement system for living bodies according to claim 1, wherein the signal extraction unit outputs a current value of the living body fluctuation component which is the value of the signal measured by the measurement unit at the current time when the signal has been subjected to fitting with a polynomial of degree n in a time window length T (seconds) that is set from the present to the past (n=an integer of 3 or more;

0.01≦

(n−

1)/2T≦

0.5).

5. The measurement system for living bodies according to claim 1, wherein the stimulus timing determination unit determines the timing of presentation of a stimulus or instruction to the subject body on the basis of the phase of the living-body fluctuation component extracted by the signal extraction unit.

6. The measurement system for living bodies according to claim 1, wherein the stimulus timing determination unit presents a stimulus or instruction to the subject body alternately at the maxima and minima of the living-body fluctuation component extracted by the signal extraction unit.

7. The measurement system for living bodies according to claim 1, wherein the stimulus timing determination unit presents a stimulus or instruction to the subject body at the maxima and minima of the living-body fluctuation component extracted by the signal extraction unit such that the number of presentation of the stimulus or instruction at the maxima equals the number of presentation of the stimulus or instruction at the minima.

8. The measurement system for living bodies according to claim 1, wherein the measurement unit comprises:

a light irradiation unit for irradiating near infrared light to the head skin of the subject body; and

a light detection unit for detecting the intensity of living-body transmitted light that has been transmitted through the subject body.