FALL DETECTION

• US 20120101770A1
• Filed: 04/27/2010
• Published: 04/26/2012
• Est. Priority Date: 04/27/2009
• Status: Active Grant

• Current Assignee: Board of Trustees of The University of Illinois, Mayo Foundation For Medical Education And Research (Mayo Clinic)
• Original Assignee: Board of Trustees of The University of Illinois, Mayo Foundation For Medical Education And Research (Mayo Clinic)
• Inventors: Kaufman, Kenton R., Gilbert, Barry K., Grabiner, Mark D.
• Granted Patent: US 8,990,041 B2
• Time in Patent Office: Days
• US Class Current: 702/141
• 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 5/1117 Fall detection
• CPC Class Codes: A61B 5/7275 Determining trends in physiological measurement data; Predicting development of a medical condition based on physiological measurements, e.g. determining a risk factor
• CPC Class Codes: G16H 50/20 for computer-aided diagnosis, e.g. based on medical expert systems

Abstract

A fall detection device may be uniquely associated with a wearer. The fall detection device may predict whether a fall event is imminent based on kinematic information of the wearer'"'"'s body. The device may also confirm whether the wearer actually experienced a fall event based on additional kinematic information.

Claims

1. A device, comprising:

at least one kinematic sensor that measures kinematic information associated with a wearer of the device, the kinematic information including threshold kinematic information and fall event kinematic information; and

a controller that analyzes the threshold kinematic information to determine whether a threshold indicative of a postural disturbance is satisfied, and determines whether a fall event is imminent based on the fall event kinematic information.

2. The device of claim 1 wherein the at least one kinematic sensor includes one or more of an accelerometer, a magnetometer, a pressure sensor, an altimeter, a velocity sensor, an angular velocity sensor or a gyroscope.

3. The device of claim 1 wherein the threshold kinematic information includes at least one of a displacement, a velocity, an acceleration, or a jerk.

4. The device of claim 3 wherein the threshold kinematic information includes at least one of a linear kinematic term or a rotational kinematic term.

5. The device of claim 1 wherein the fall event kinematic information includes at least one of a displacement, a velocity, an acceleration, or a jerk.

6. The device of claim 5 wherein the fall event kinematic information includes at least one of a linear kinematic term or a rotational kinematic term.

7. The device of claim 1 wherein the controller further determines a fall direction based on the threshold kinematic information.

8. The device of claim 7 wherein the fall event kinematic information includes an acceleration in the fall direction.

9. The device of claim 7 wherein the fall event kinematic information includes an acceleration in the fall direction measured at a first predetermined time, a vertical displacement measured at a second predetermined time, and a vertical displacement measured at a third predetermined time.

10. The device of claim 1 wherein the kinematic information further includes confirmatory kinematic information.

11. The device of claim 10 wherein the controller further confirms whether the wearer has actually experienced a fall event based on the confirmatory kinematic information.

12. The device of claim 10 wherein the confirmatory kinematic information includes at least one of a maximum vertical deceleration and a vertical displacement measured at the time of the maximum vertical deceleration.

13. The device of claim 10 wherein the confirmatory kinematic information includes at least one of an anteroposterior (AP) acceleration, a medial-lateral (M/L) acceleration, and a vertical (z) acceleration.

14. The device of claim 10 wherein the controller further generates a fall event signal if the fall event is confirmed.

15. The device of claim 1 wherein the threshold kinematic information includes at least one of an anteroposterior (AP) acceleration, a medial-lateral (M/L) acceleration, and a vertical (z) acceleration.

16. The device of claim 1 wherein the controller determines whether a fall event is imminent by generating a Wald-Anderson classification statistic based on the fall event kinematic information.

17. The device of claim 16 wherein the controller determines that a fall event is imminent if the Wald-Anderson classification statistic is less than 0, and determines that a fall event is not imminent if the Wald-Anderson classification statistic is greater than 0.

18. The device of claim 1 wherein the controller determines whether a fall is imminent based on a discriminant function of the fall event kinematic information.

19. The device of claim 18 wherein the discriminant function is a linear discriminant function or a quadratic discriminant function.

20. The device of claim 18 wherein the discriminant function is a Wald-Anderson classification function.

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39. A device, comprising:

at least one kinematic sensor that measures threshold kinematic information associated with movement of a wearer of the device, the threshold kinematic information including at least one of a linear acceleration or a rotational acceleration;

a controller that identifies a time of postural disturbance at which the threshold kinematic information satisfies a threshold indicative of a postural disturbance that may lead to the user experiencing a fall event; and

at least one kinematic sensor that measures fall event kinematic information associated with movement of the wearer subsequent to satisfaction of the threshold, fall event kinematic information including at least one of a linear acceleration at a first predetermined time after the time of postural disturbance;

wherein the controller further predicts whether the user will experience a fall based on the fall event kinematic information.

40. The device of claim 39 wherein the at least one kinematic sensor that measures threshold kinematic information and the at least one kinematic sensor that measures fall event kinematic information include the same kinematic sensor.