# US 2009/0260426 A1 · Determining Postural Stability

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- Number: US 2009/0260426 A1
- Document ID: US20090260426A1
- Status: Published application
- Kind: A1
- Application number: 12/323,912
- Filed: 2008-11-26
- Published: 2009-10-22
- Earliest claimed: 2007-11-28
- Assignees: Massachusetts Institute of Technology; President and Fellows of Harvard College
- Inventors: Erez Lieberman; Katharine E. Forth; William H. Paloski
- Web page: https://patentgrep.com/patent/US20090260426A1

## CPC

- A61B 5/1036: {Measuring load distribution, e.g. podologic studies}
- A61B 5/0022: {Monitoring a patient using a global network, e.g. telephone networks, internet}
- A61B 5/1038: {Measuring plantar pressure during gait}
- A61B 5/1116: {Determining posture transitions}
- A61B 5/1117: {Fall detection}
- A61B 5/1118: {Determining activity level}
- A61B 5/1123: {Discriminating type of movement, e.g. walking or running (A61B5/1116, A61B5/112 take precedence)}
- A61B 5/4023: {Evaluating sense of balance}
- A61B 5/6807: {Footwear}
- A61B 5/6829: {Foot or ankle}
- G01G 19/44: for weighing persons
- G01G 23/3735: {using a digital network}
- G16H 40/67: for remote operation
- G16Z 99/00: Subject matter not provided for in other main groups of this subclass
- A61B 2503/40: Animals
- A61B 2562/0247: Pressure sensors
- A61B 2562/046: in a matrix array
- A61B: DIAGNOSIS; SURGERY; IDENTIFICATION (usefulness limited to only animals A61D)
- G01G: WEIGHING (sorting by weighing B07C5/16)
- G16H: HEALTHCARE INFORMATICS, i.e. INFORMATION AND COMMUNICATION TECHNOLOGY [ICT] SPECIALLY ADAPTED FOR THE HANDLING OR PROCESSING OF MEDICAL OR HEALTHCARE DATA
- G16Z: INFORMATION AND COMMUNICATION TECHNOLOGY [ICT] SPECIALLY ADAPTED FOR SPECIFIC APPLICATION FIELDS, NOT OTHERWISE PROVIDED FOR

## Abstract

A method for determining postural stability of a person can include acquiring a plurality of pressure data points over a period of time from at least one pressure sensor. The method can also include the step of identifying a postural state for each pressure data point to generate a plurality of postural states. The method can include the step of determining a postural state of the person at a point in time based on at least the plurality of postural states.

## Claims

### Claim 1

A method for determining postural stability of a person, the method comprising:
acquiring a plurality of pressure data points over a period of time from at least one pressure sensor;
identifying a postural state for each pressure data point to generate a plurality of postural states; and
determining a postural state of the person at a point in time based on at least the plurality of postural states.

### Claim 2 (depends on 1)

The method of claim 1, wherein the postural state is at least one of a static postural state or a dynamic postural state.

### Claim 3 (depends on 2)

The method of claim 2, wherein the person is in the dynamic postural state when moving from a first static postural state to a second static postural state.

### Claim 4 (depends on 2)

The method of claim 2, further comprising determining that the person is posturally stable or posturally unstable based on a number of times the person is in the dynamic postural state.

### Claim 5 (depends on 2)

The method of claim 2, wherein the plurality of postural states follows a punctuated equilibrium, a continuous series of static postural states defining an equilibrium.

### Claim 6 (depends on 5)

The method of claim 5, further comprising determining that the person is posturally stable or posturally unstable based on a number of distinct equilibria.

### Claim 7 (depends on 2)

The method of claim 2, wherein determining the postural state of the person at the point in time is based on at least probability of transitioning between the static postural state and the dynamic postural state.

### Claim 8 (depends on 7)

The method of claim 7, further comprising calculating the probability of transitioning between the static postural state and the dynamic postural state based on the plurality of postural states of the person over the period of time.

### Claim 9 (depends on 1)

The method of claim 1, further comprising acquiring at least one of an acceleration or a location of the person over the period of time.

### Claim 10 (depends on 1)

The method of claim 1, further comprising determining a range of postural stability states based on the plurality of pressure data points.

### Claim 11 (depends on 1)

The method of claim 1, wherein determining comprises using a machine learning technique on the plurality of pressure data points to generate the plurality of postural states.

### Claim 12 (depends on 11)

The method of claim 11, wherein determining comprises using a Hidden Markov Model on the plurality of pressure data points or applying Bayesian segmentation to the plurality of pressure data points to generate the plurality of postural states.

### Claim 13 (depends on 1)

The method of claim 1, wherein acquiring comprises acquiring a plurality of pressure data points from at least one pressure sensor on at least one of a shoe, a sock, a sole insert, a cane, a crutch, a walker, a walking aid, a prosthetic leg, or a robotic leg.

### Claim 14 (depends on 1)

The method of claim 1, wherein each of the plurality of pressure data points reflects a location of a center of mass of the person at a point in time.

### Claim 15 (depends on 14)

The method of claim 14, wherein identifying comprises grouping a selected set of the plurality of pressure data points as corresponding to a static postural state based on the location of the center of mass of the person of each of the plurality of pressure data points.

### Claim 16 (depends on 1)

The method of claim 1, wherein determining comprises determining in real time, a subsequent postural state of the person based on the plurality of pressure data points.

### Claim 17 (depends on 1)

The method of claim 1, wherein determining comprises determining a current postural state or a subsequent postural state of the person by based on the plurality of pressure data points, wherein the plurality of pressure data points were acquired during a previous period in time.

### Claim 18

A method for determining postural stability, the method comprising:
acquiring at least a first pressure data point and a second pressure data point from at least one pressure sensor;
identifying a first postural state and a second postural state based on the first and second pressure data points; and
determining a postural state at a point in time based on at least the first postural state and the second postural state.

### Claim 19 (depends on 18)

The method of claim 18, wherein determining comprises determining a subsequent postural state of a person.

### Claim 20 (depends on 18)

The method of claim 18, wherein identifying comprises identifying the first postural state as static or dynamic and the second postural state as static or dynamic.

### Claim 21 (depends on 20)

The method of claim 20, wherein determining comprises determining a subsequent postural state of a person based a probability of transitioning between the static postural state and the dynamic postural state.

### Claim 22 (depends on 18)

The method of claim 18, further comprising determining that a person is posturally stable or posturally unstable based on at least the identified first postural state and the identified second postural state.

### Claim 23 (depends on 18)

The method of claim 18, wherein acquiring comprises acquiring a plurality of pressure data points from at least one pressure sensor on at least one of a shoe, a sock, a sole insert, a cane, a crutch, a walker, a walking aid, a prosthetic leg, a robotic leg, a vehicle, or an axle connected to at least one wheel.

### Claim 24

A system for determining postural stability of a person comprising:
at least one pressure sensor coupled to the person that acquires a plurality of pressure data points over a period of time;
means for identifying a postural state for each pressure data point;
means for generating a plurality of postural states of the person over the period of time; and
means for determining a postural state of the person at a point in time based on the plurality of postural states.

### Claim 25 (depends on 24)

The system of claim 24, wherein the postural state of a person is one of a static postural state or a dynamic postural state.

### Claim 26 (depends on 24)

The system of claim 24, wherein each pressure data point corresponds to a center of gravity of the person at a point in time.