Sleep diagnosis device

• US 20090062628A1
• Filed: 05/17/2006
• Published: 03/05/2009
• Est. Priority Date: 05/18/2005
• Status: Active Grant

• Current Assignee: Panasonic Electric Works Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Asahi Matsushita Electric Works Ltd. (Panasonic Holdings Corporation)
• Inventors: Fukushima, Shogo, Nakatsukasa, Aki, Yamamoto, Matsuki
• Granted Patent: US 7,766,841 B2
• Time in Patent Office: Days
• US Class Current: 600/301
• CPC Class Codes: A61B 2562/0219 Inertial sensors, e.g. accelerometers, gyroscopes, tilt switches
• CPC Class Codes: A61B 5/08 Detecting, measuring or recording devices for evaluating the respiratory organs A61B5/0205 takes precedence
• CPC Class Codes: A61B 5/1116 Determining posture transitions
• CPC Class Codes: A61B 5/1135 by monitoring thoracic expansion
• CPC Class Codes: A61B 5/4806 Sleep evaluation A61B5/4821 takes precedence; devices for inducing sleep A61M21/02

Abstract

The sleep diagnosis device 1 of the present invention comprises three-dimensional acceleration sensors 2a and 2b, a posture detector 5 which detects a posture of the patient from a DC component of the three-dimensional acceleration sensors, and a breathing movement detector 4 which detects a breathing movement of the patient from the AC component of the three-dimensional acceleration sensors. The sleep diagnosis device of the present invention can detect the posture (sleeping posture) and the breathing movement of the patient by using one three-dimensional acceleration sensor, so it is possible to reduce the number of sensors. Furthermore, the sleep diagnosis device can detect the breathing movement accurately by the three-dimensional acceleration sensors.

Claims

1. A sleep diagnosis device comprising:

a three-dimensional acceleration sensor,

a posture detector configured to detect a posture of a patient from a DC component of said three-dimensional acceleration sensor,

a breathing movement detector configured to detect a breathing movement of the patient from an AC component of said three-dimensional acceleration sensor.

2. The sleep diagnosis device as set forth in claim 1, wherein

said breathing movement detector includes:

a one-dimensional converting means configured to generate one-dimensional acceleration data from the three-dimensional acceleration data obtained by said three-dimensional acceleration sensor,

an inflection point detecting means configured to detect inflection points of a variation of said one-dimensional acceleration data from the one-dimensional acceleration data generated by said one-dimensional converting means, and

a breathing movement calculating means configured to calculate the breathing movement of the patient from the inflection points of the variation of the one-dimensional acceleration data obtained by said inflection point detecting means.

3. The sleep diagnosis device as set forth in claim 2, wherein

said one-dimensional converting means comprises:

a principal axis calculating means configured to calculate a principal axis of the variation of the acceleration from the three-dimensional acceleration data obtained by said three-dimensional acceleration sensor,

a one-dimensional data generating means configured to generate the one-dimensional acceleration data by projecting the three-dimensional acceleration data onto the principal axis calculated by said principal axis calculating means.

4. The sleep diagnosis device as set forth in claim 3, wherein

said principal axis calculating means is configured to calculate an approximate plane from the three-dimensional acceleration data and to generate a two-dimensional acceleration data by projecting the three-dimensional acceleration data onto the approximate plane and to calculate an approximate line from the two-dimensional acceleration data,

said one-dimensional data generating means being configured to use the approximate line calculated by said principal axis calculating means as a principal axis and to generate the one-dimensional acceleration data by projecting the two-dimensional acceleration data onto the principal axis.

5. The sleep diagnosis device as set forth in claim 3, wherein

said principal axis calculating means is configured to calculate an approximate line by using the three-dimensional acceleration data,

said one-dimensional data generating means being configured to use the approximate line calculated by said principal axis calculating means as a principal axis and to generate the one-dimensional acceleration data by projecting the three-dimensional acceleration data onto the principal axis.

6. The sleep diagnosis device as set forth in claim 2, wherein

said breathing movement calculating means includes a breathing rate calculating means configured to calculate a breathing rate of the patient per unit of time by using a time difference between a certain convex inflection point and the next convex inflection point or a time difference between a certain concave inflection point and the next concave inflection point, out of the inflection points of the variation of the one-dimensional acceleration data.

7. The sleep diagnosis device as set forth in claim 2, wherein

said breathing movement calculating means includes an apnea detecting means configured to detect an interval between adjacent inflection points of the variation of the one-dimensional acceleration data as an apnea interval if a time difference between the adjacent inflection points is greater than a criterion value.

8. The sleep diagnosis device as set forth in claim 7, wherein

said breathing movement calculating means further includes an apnea period detecting means configured to get a start time of the apnea interval as a breathing stop time and get a stop time of the apnea interval as a breathing start time when said apnea detecting means detects the apnea interval.

9. The sleep diagnosis device as set forth in claim 2, wherein

said breathing movement detector includes a breathing strength calculating means configured to calculate strength of a breath by using intensity difference between adjacent inflection points of the variation of the one-dimensional acceleration data.

10. The sleep diagnosis device as set forth in claim 1, wherein

said posture detector calculates a trunk angle of the patient from each component DCy and DCz of the DC component of said three acceleration sensor in a y-axis and a z-axis directions, and calculates a sleeping posture angle of the patient from each component DCx and DCz of the DC component of the three acceleration sensor in a x-axis and z-axis directions, when the x-axis direction is defined as a left-right direction of the patient and the y-axis direction is defined as a body height direction of the patient and the z-axis direction is defined as a thickness direction of the patient.

11. The sleep diagnosis device as set forth in claim 1, further comprises

a heart rate detector configured to detect a heart rate of the patient from the AC component of said three-dimensional acceleration sensor.

12. The sleep diagnosis device as set forth in claim 11, wherein

said heart rate detector detects the heart rate of the patient by filtering a component ACz of the AC component of the three dimensional acceleration sensor in a z-axis direction by a band-pass filter and calculating an inverse of a peak period of the filtered component ACz.