Fall prevention
First Claim
Patent Images
1. A fall prevention device, comprising:
- at least one sensor configured to measure the motion of a user wearing the device;
an alarm; and
a processor programmed to;
determine a value for one or more parameters related only to a gait of the user from the measurements, wherein the one or more parameters includes a forward step size and a lateral step size, and wherein the processor is further programmed to;
integrate horizontal components of the received motion measurements with integral bounds being given by consecutive identified step boundaries to give a start and end position for a step;
determine a norm of the vector connecting the start and end positions to the current value of the forward step size;
define a straight line between the start and end positions;
integrate collected motion measurements occurring during the step to give a series of positions during the step;
determine a distance between each position of the series and the straight line; and
determine a maximum distance of the series of positions as the lateral step size; and
determine a fall risk for the user to trigger a warning of an increased risk of falling, wherein the fall risk is determined from a comparison of the value with a normal value for the one or more parameters determined from motion of the user in which the user is at a normal risk of falling, wherein the determination of the fall risk further comprises;
receive motion measurements over a first period of time when the user is walking normally;
determine a mean μ
of values for the one or more parameters from the motion measurements over the first period of time;
determine a standard deviation σ
of the mean μ
;
receive motion measurements subsequent to the first period of time;
determine a current value a of the one or more parameters from the motion measurements received subsequent to the first period of time;
periodically calculate
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Abstract
A fall risk of a user is determined by collecting measurements of the motion of the user. A value for a parameter related to the gait of the user is estimated from the measurements. The fall risk for the user is determined from a comparison of the estimated value with a normal value for the parameter determined from motion of the user in which the user is at their normal risk of falling.
24 Citations
13 Claims
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1. A fall prevention device, comprising:
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at least one sensor configured to measure the motion of a user wearing the device; an alarm; and a processor programmed to; determine a value for one or more parameters related only to a gait of the user from the measurements, wherein the one or more parameters includes a forward step size and a lateral step size, and wherein the processor is further programmed to; integrate horizontal components of the received motion measurements with integral bounds being given by consecutive identified step boundaries to give a start and end position for a step; determine a norm of the vector connecting the start and end positions to the current value of the forward step size; define a straight line between the start and end positions; integrate collected motion measurements occurring during the step to give a series of positions during the step; determine a distance between each position of the series and the straight line; and determine a maximum distance of the series of positions as the lateral step size; and determine a fall risk for the user to trigger a warning of an increased risk of falling, wherein the fall risk is determined from a comparison of the value with a normal value for the one or more parameters determined from motion of the user in which the user is at a normal risk of falling, wherein the determination of the fall risk further comprises; receive motion measurements over a first period of time when the user is walking normally; determine a mean μ
of values for the one or more parameters from the motion measurements over the first period of time;determine a standard deviation σ
of the mean μ
;receive motion measurements subsequent to the first period of time; determine a current value a of the one or more parameters from the motion measurements received subsequent to the first period of time; periodically calculate - View Dependent Claims (2, 3, 4, 5, 6)
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7. A method of determining a fall risk of a user using a device comprising one or more motion measuring sensors and one or more processors, the method comprising:
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with the one or more motion measuring sensors, collecting measurements of motion of the user; with the one or more processors; estimating a value for one or more parameters related only to a gait of the user from the measurements, wherein the one or more parameters comprises a forward step size and a lateral step size, further comprising; integrating horizontal components of the received motion measurements with integral bounds being given by consecutive identified step boundaries to give a start and end position for a step; determining a norm of the vector connecting the start and end positions to the current value of the forward step size; defining a straight line between the start and end positions; integrating collected motion measurements occurring during the step to give a series of positions during the step; determining a distance between each position of the series and the straight line; and determining a maximum distance of the series of positions as the lateral step size; and determining a fall risk for the user to trigger a warning of an increased risk of falling, wherein the fall risk is determined from a comparison of the estimated value with a normal value for the one or more parameters determined from motion of the user in which the user is at a normal risk of falling, wherein the determining further comprises; receiving motion measurements over a first period of time when the user is walking normally; determining a mean μ
of values for the one or more parameters from the motion measurements over the first period of time;determining a standard deviation σ
of the mean μ
;receiving motion measurements subsequent to the first period of time; determining a current value a of the one or more parameters from the motion measurements received subsequent to the first period of time; periodically calculating - View Dependent Claims (8, 9, 10, 11)
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12. A method of determining a fall risk of a user using a device comprising one or more motion measuring sensors and one or more processors, the method comprising:
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with the one or more motion measuring sensors, collecting measurements of motion of the user; with the one or more processors; estimating a value for one or more parameters related to a gait of the user from the measurements, wherein estimating the value of the one or more parameters includes; identifying a step boundary by identifying clusters of contiguous measurements in the collected measurements in which at least one of; a magnitude of each of the measurements exceeds a threshold; a magnitude of each of the measurements exceeds a threshold, apart from a subset of the measurements whose magnitude is less than the threshold, provided that the subset covers a time period less than a time threshold; and wherein the collected measurements whose magnitude exceeds a first threshold denotes a first measurement in a cluster and a first collected measurement after the first measurement in the cluster whose magnitude falls below a second threshold denotes a last measurement in the cluster, and in which the last measurement is more than a minimum period after the first measurement; wherein the one or more parameters comprises a step size and the step of estimating a value for the one or more parameters comprises computing a double integration with respect to time of the horizontal components of the collected measurements relating to acceleration with integration constants being set to zero at the beginning of the step; wherein the one or more parameters comprises a lateral step size and the step of estimating a value for the one or more parameters further comprises;
defining a straight line between the start and end positions;
integrating collected measurements occurring during the step to give a series of positions during the step;
determining the distance between each position and the straight line; and
determining the lateral step size as the maximum distance in this series; anddetermining a fall risk for the user, wherein the fall risk is determined from a comparison of the estimated value with a normal value for the one or more parameters determined from motion of the user in which the user is at a normal risk of falling.
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13. A fall prevention device, comprising:
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at least one sensor configured to measure the motion of a user wearing the device; and a processor programmed to; determine a value for one or more parameters related only to a gait of the user from the measurements; and determine a fall risk for the user to trigger a warning of an increased risk of falling, wherein the fall risk is determined from a comparison of the value with a normal value for the one or more parameters determined from motion of the user in which the user is at a normal risk of falling, wherein the one or more parameters includes both average forward direction step length and average lateral direction step width over a first period of time when the user is walking normally and a second period of time, and wherein the second period of time is shorter than the first period of time.
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Specification