Body movement monitoring system and method

• US 7,141,026 B2
• Filed: 10/01/2001
• Issued: 11/28/2006
• Est. Priority Date: 10/05/2000
• Status: Expired due to Term

• Current Assignee: EPFL - Ecole Polytechnique Federale de Lausanne
• Original Assignee: EPFL - Ecole Polytechnique Federale de Lausanne
• Inventors: Aminian, Kamiar, Najjafi, Bijian
• Primary Examiner(s): Hindenburg, Max F.
• Assistant Examiner(s): FOREMAN, JONATHAN M
• Application Number:
  US10/398,462
• Publication Number:
  US 20040015103A1
• Time in Patent Office: 1,884 Days
• Field of Search: 600587-595
• US Class Current: 600/595
• CPC Class Codes: A61B 2503/08 Elderly
• CPC Class Codes: A61B 2562/0219 Inertial sensors, e.g. accelerometers, gyroscopes, tilt switches
• CPC Class Codes: A61B 5/1116 Determining posture transitions
• 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 5/1127 using markers
• CPC Class Codes: A61B 5/6823 Trunk, e.g., chest, back, abdomen, hip
• CPC Class Codes: A61B 5/726 using Wavelet transforms
• CPC Class Codes: A63B 23/0244 with signalling or indicating means, e.g. of incorrect posture, for deep-breathing exercises
• CPC Class Codes: G08B 21/0446 worn on the body to detect changes of posture, e.g. a fall, inclination, acceleration, gait

Abstract

The present invention relates to a system and a method for monitoring body movement, in particular but not exclusively for evaluating the falling risk and/or for monitoring sitting, standing, lying, walking and running periods. The system is characterized by the fact that it comprises means for determining the time of postural transition.

Claims

1. A body movement monitoring system comprising:

a sensor to be attached to a trunk of a subject,

processing means for deriving information from said sensor,

display means for displaying said information to an operator,

wherein said system includes means for determining the time of postural transition by calculating a trunk tilt θ

by integrating an angular rate signal measured by said sensor, calculating sin θ

, and obtaining the postural transition corresponding to the minimum peak of sin θ

.

2. A monitoring system according to claim 1 wherein the sensor comprises a miniature gyroscope.

3. A monitoring system according to claim 1 wherein said system includes means to determine the duration and the type of postural transition.

4. A monitoring system according to claim 1 comprising an alarm which is activated when the quality of postural transition is behind a threshold.

5. A monitoring system according to claim 1 comprising furthermore a vertical accelerometer.

6. A monitoring system according to claim 5 comprising furthermore a forward accelerometer.

7. A method for measuring the time of postural transition comprising:

attaching a sensor to a trunk of a subject,

processing information from said sensor,

displaying said information to an operator,

determining the time when a postural transition occurs, wherein a trunk tilt θ

is first calculated by integrating an angular rate signal measured by said sensor, sin θ

is then calculated, and the postural transition corresponds to the minimum peak of sin θ

.

8. A method according to claim 7 wherein a duration of postural transition is determined based on the duration between the maximum peaks of sin θ

which occur before and after the instant of postural transition.

9. A method according to claim 7 wherein the method further determines a duration and a type of postural transition and wherein falling risk is determined by a combination of three parameters comprising an average and standard deviation of transition duration and an occurrence of abnormal successive transition.

10. A method according to claim 7 further comprising monitoring and measuring physical activity via a vertical accelerometer.