APPARATUS FOR AND METHOD OF BIOTIC SLEEP STATE DETERMINING

• US 20080027331A1
• Filed: 10/02/2007
• Published: 01/31/2008
• Est. Priority Date: 03/30/2004
• Status: Active Grant

• Current Assignee: TDK Corporation
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: Suzuki, Takuji, Ouchi, Kazushige, Kameyama, Kenichi
• Granted Patent: US 7,608,046 B2
• Time in Patent Office: Days
• US Class Current: 600/483
• CPC Class Codes: A61B 2562/0219 Inertial sensors, e.g. accelerometers, gyroscopes, tilt switches
• CPC Class Codes: A61B 5/0205 Simultaneously evaluating both cardiovascular conditions and different types of body conditions, e.g. heart and respiratory condition
• CPC Class Codes: A61B 5/02438 with portable devices, e.g. worn by the patient
• CPC Class Codes: A61B 5/11 Measuring movement of the entire body or parts thereof, e.g. head or hand tremor, mobility of a limb for measuring pulse A61B5/02 ;A61B5/1038 takes precedence; motion detection to correct for motion artifacts in physiological signals A61B5/721
• CPC Class Codes: A61B 5/1123 Discriminating type of movement, e.g. walking or running A61B5/1116, A61B5/112 take precedence
• CPC Class Codes: A61B 5/4035 Evaluating the autonomic nervous system
• CPC Class Codes: A61B 5/4809 Sleep detection, i.e. determining whether a subject is asleep or not
• CPC Class Codes: A61B 5/4812 Detecting sleep stages or cycles
• CPC Class Codes: A61B 5/681 Wristwatch-type devices
• CPC Class Codes: A61B 5/6892 Mats
• CPC Class Codes: A61B 5/7239 using differentiation including higher order derivatives

Abstract

A biotic sleep state determining apparatus that determines a sleep state of a subject based on a series of pulse interval data that indicate a time interval of one cycle of a pulse wave of the subject, and on body movement data that indicates a body movement of the subject, the apparatus includes a body movement determining unit that determines that the body movement occurs if a fluctuation amount of the body movement data is greater than a first predetermined threshold, a pulse interval data processor that processes the series of pulse interval data after removing pulse interval data measured in parallel with the body movement data from the series of pulse interval data, if the body movement determining unit determines that the body movement occurs, and a sleep state determining unit that determines the sleep state based on autonomic nerve indexes acquired from the series of pulse interval data processed by the pulse interval data processor.

Claims

1. A biotic sleep state determining apparatus that determines a sleep state of a subject based on a series of pulse interval data that indicate a time interval of one cycle of a pulse wave of the subject, and on body movement data that indicates a body movement of the subject, the apparatus comprising:

a body movement determining unit configured to determine that the body movement occurs if a fluctuation amount of the body movement data is greater than a first predetermined threshold;

a pulse interval data processor that processes the series of pulse interval data after removing pulse interval data measured in parallel with the body movement data from the series of pulse interval data, if the body movement determining unit determines that the body movement occurs; and

a sleep state determining unit configured to determine the sleep state based on autonomic nerve indexes acquired from the series of pulse interval data processed by the pulse interval data processor.

2. The sleep state determining apparatus according to claim 1, further comprising:

an awakening determining unit configured to determine that the body movement occurs during awakening if an occurrence frequency of the body movement determined by the body movement determining unit is equal to or greater than a second predetermined threshold, and that determines that the body movement occurs during sleep if the occurrence frequency of the body movement is smaller than the second predetermined threshold, wherein

the pulse interval data processor that processes the series of pulse interval data after removing the pulse interval data measured in parallel with the body movement data determined as the body movement during sleep from the series of pulse interval data, if the awakening determining unit determines that the body movement occurs during sleep.

3. The sleep state determining apparatus according to claim 2, wherein

the awakening determining unit configured to determine that the body movement occurs during the awakening if the occurrence frequency of the body movement determined by the body movement determining unit is equal to or greater than the second predetermined threshold, and if the pulse interval data is shorter than an average of past pulse interval data during the sleep.

4. The sleep state determining apparatus according to claim 2, further comprising:

an abnormality data remover that removes the pulse interval data measured in parallel with the body movement data determined as the body movement by the awakening determining unit from the series of pulse interval data, if the awakening determining unit determines that the body movement occurs, and

the pulse interval data processor that processes the series of pulse interval data after the abnormality data remover removes the pulse interval data measured in parallel with the body movement data determined as the body movement from the series of pulse interval data.

5. The sleep state determining apparatus according to claim 1, further comprising:

a body movement measuring unit configured to measure acceleration data in three-axis directions as the body movement data; and

a body movement sampling data processor that differentiates the acceleration data in the three-axis directions measured by the body movement measuring unit by time, that obtains differential coefficients of the acceleration data in the three-axis directions, and that calculates a fluctuation amount of the body movement data, the fluctuation amount of the body movement data being a square root of a sum of squares of the differential coefficients of the acceleration data in the three-axis directions, wherein

the body movement determining unit configured to determine that the body movement occurs if the fluctuation amount of the body movement data calculated by the body movement sampling data processor is greater than the first predetermined threshold.

6. A biotic sleep state determining method of determining a sleep state of a subject based on a series of pulse interval data that indicate a time interval of one cycle of a pulse wave of the subject, and on body movement data that indicates a body movement of the subject, the method comprising:

determining that the body movement occurs if a fluctuation amount of the body movement data is greater than a first predetermined threshold;

processing the series of pulse interval data after removing pulse interval data measured in parallel with the body movement data from the series of pulse interval data, if the body movement occurs; and

determining the sleep state based on autonomic nerve indexes acquired from the series of pulse interval data processed.