PHYSIOLOGICAL AND BEHAVIORAL SENSORS AND METHODS

• US 20120071792A1
• Filed: 09/16/2010
• Published: 03/22/2012
• Est. Priority Date: 09/16/2010
• Status: Active Grant

• Current Assignee: Charles Stark Draper Laboratory Incorporated
• Original Assignee: Charles Stark Draper Laboratory Incorporated
• Inventors: Pfeffer, Lawrence E., Wendelken, Suzanne M., Fulford, Adam T., Webb, Andrea K.
• Granted Patent: US 8,540,651 B2
• Time in Patent Office: Days
• US Class Current: 600/587
• CPC Class Codes: A61B 2562/0252 Load cells
• CPC Class Codes: A61B 2562/046 in a matrix array
• 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 5/1102 Ballistocardiography
• CPC Class Codes: A61B 5/164 Lie detection
• CPC Class Codes: A61B 5/165 Evaluating the state of mind, e.g. depression, anxiety
• CPC Class Codes: A61B 5/4023 Evaluating sense of balance
• CPC Class Codes: A61B 5/6891 Furniture
• CPC Class Codes: A61B 5/70 Means for positioning the patient in relation to the detecting, measuring or recording means
• CPC Class Codes: G01G 19/50 having additional measuring devices, e.g. for height

Abstract

In various embodiments, a physiological or behavioral signal is derived from a vertical force resulting from the entire weight of a subject.

Claims

1. A system for measuring physiological and behavioral signals in a human subject, the system comprising:

at least one force sensor for measuring vertical force imparted by an entire weight of the subject; and

a signal processor for deriving a physiological or behavioral signal from the measured force.

2. The system of claim 1, wherein the at least one force sensor measures only substantially vertical force.

3. The system of claim 1, further comprising a structure for supporting a posture of the subject that includes a substantially vertical thorax.

4. The system of claim 1, further comprising a platform for bearing the subject.

5. The system of claim 4, further comprising a bearing disposed between each said at least one force sensor and the platform, the bearing substantially transmitting vertical force but not torque from the platform to the force sensor.

6. The system of claim 4, wherein the at least one force sensor comprises at least three non-collinear force sensors disposed proximate a periphery of the platform.

7. The system of claim 4, further comprising, disposed entirely on the platform such that its entire weight is supported thereby, at least one of a substantially stationary support or a chair.

8. The system of claim 1, wherein the signal processor comprises at least one calibration module for calibrating the vertical force, thereby substantially eliminating at least one of bias, slope error, hysteresis, or non-linearity from the vertical force.

9. The system of claim 1, wherein the signal processor comprises at least one taring module for subtracting from the vertical force a weight contribution from the platform.

10. The system of claim 1, wherein (i) the at least one force sensor comprises a plurality of force sensors, and (ii) the signal processor comprises a summation module for summing vertical force measured by each of the force sensors.

11. The system of claim 1, wherein the signal processor comprises a high-pass filtering module for removing a steady-state component from a total vertical force measured by the at least one force sensor.

12. The system of claim 11, wherein the high-pass filtering module removes from the total vertical force a spectral component having a frequency below a cardiac frequency of interest.

13. The system of claim 11, wherein the high-pass filtering module comprises a Bessel filter.

14. The system of claim 1, wherein the signal processor comprises a low-pass filtering module for removing, from a total vertical force measured by the at least one force sensor, a spectral component having a frequency above a cardiac frequency of interest.

15. The system of claim 1, wherein the physiological or behavioral signal comprises a ballistocardiogram.

16. The system of claim 1, wherein the signal processor comprises a centroid-calculating module for determining a center of gravity of the subject based on the measured force.

17. The system of claim 16, wherein the physiological or behavioral signal comprises at least one of jitter or hypervigilance.

18. A method for measuring physiological and behavioral signals, the method comprising:

measuring a vertical force imparted by an entire weight of a human subject having a substantially vertical thorax; and

extracting a physiological or behavioral signal from the measured vertical force.

19. The method of claim 18, wherein the physiological or behavioral signal is extracted without sensors attached to the subject.

20. The method of claim 18, further comprising calibrating the measured vertical force to substantially eliminate at least one of bias, slope error, hysteresis, or non-linearity therefrom.

21. The method of claim 18, wherein the subject is supported by a platform, further comprising subtracting from the vertical force a weight contribution of the platform.

22. The method of claim 18, wherein extracting the physiological or behavioral signal comprises removing from the measured vertical force at least one spectral component having a frequency above or below a cardiac frequency of interest.

23. The method of claim 18, wherein extracting the physiological or behavioral signal comprises removing from the measured vertical force a steady-state component corresponding to the entire weight of the subject.

24. The method of claim 18, wherein the physiological or behavioral signal comprises a ballistocardiogram.

25. The method of claim 18, wherein extracting the physiological or behavioral signal comprises determining a center of gravity of the subject.

26. The method of claim 18, wherein the physiological or behavioral signal comprises at least one of jitter or hypervigilance.

27. The method of claim 18, wherein the vertical force is measured by a plurality of force sensors disposed proximate a periphery of and supporting a platform, the platform supporting the subject.

28. The method of claim 18, further comprising at least one of interviewing the subject or subjecting the subject to a cognitive stimulus while measuring the vertical force.