U.S. patent application number 15/247988 was filed with the patent office on 2017-02-09 for system for assessing postural sway and human motion.
The applicant listed for this patent is SWAY MEDICAL LLC. Invention is credited to Chase Curtiss.
Application Number | 20170035343 15/247988 |
Document ID | / |
Family ID | 47627401 |
Filed Date | 2017-02-09 |
United States Patent
Application |
20170035343 |
Kind Code |
A1 |
Curtiss; Chase |
February 9, 2017 |
SYSTEM FOR ASSESSING POSTURAL SWAY AND HUMAN MOTION
Abstract
There is provided herein a system and method for performing a
balance evaluation that utilizes a hand held accelerometer that
measures upper body compensatory and correctional movement. Instead
of testing movement in the waist or lower extremity as is commonly
done, the instant invention measures thoracic trunk sway to
estimate an individual's balance via positional change algorithms.
By holding the measuring device to the chest and performing one or
a variety of balance tests, the instant invention can determine the
amount of sway in the trunk without attached or fixed monitors,
which presents a novel approach to assessing postural sway above
the center of mass.
Inventors: |
Curtiss; Chase; (TULSA,
OK) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
SWAY MEDICAL LLC |
TULSA |
OK |
US |
|
|
Family ID: |
47627401 |
Appl. No.: |
15/247988 |
Filed: |
August 26, 2016 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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13564401 |
Aug 1, 2012 |
9451916 |
|
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15247988 |
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61514211 |
Aug 2, 2011 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61B 2503/10 20130101;
A61B 2562/0219 20130101; A61B 5/6898 20130101; A61B 5/4023
20130101; A61B 5/1116 20130101; A61B 5/1121 20130101 |
International
Class: |
A61B 5/00 20060101
A61B005/00; A61B 5/11 20060101 A61B005/11 |
Claims
1-8. (canceled)
9. A system for assessing a subject's postural stability,
comprising: (a) a handheld computing device, comprising: (1) a
three-axis accelerometer, (2) memory, (3) a screen, and, (4) a CPU
in electronic communication with said screen, said three-axis
accelerometer and with said memory, said CPU at least for executing
a plurality of program instructions stored in said memory, said
plurality of program instructions comprising the steps of: (i)
instructing a subject to clasp a three-component accelerometer
against an upper torso of the subject; (ii) instructing the subject
to perform a task while the three-component accelerometer is so
clasped; (iii) continuously recording an output of said
accelerometer during the subject's performance of said task,
thereby obtaining a plurality of three-component accelerometer
measurements during the performance of said task; (iv) determining
from at least a portion of said plurality of three-component
accelerometer measurements an indicium representative of the
subject's postural stability; (v) using at least said indicium to
determine whether the subject's postural stability is within a
normal range; (vi) if the subject's postural stability is within
said normal range, displaying on said screen an indication that the
subject's postural stability is within said normal range and taking
no further action with respect to the subject; and, (vii) if the
subject's postural stability is not within said normal range,
displaying on said screen an indication that the subject's postural
stability is not within said normal range.
10. The system for assessing a subject's postural stability
according to claim 9 wherein said handheld computer is selected
from the group consisting of an iPhone.RTM., an iPod.RTM., an iPod
Touch.RTM., an Andriod.RTM. cell phone, and a Blackberry.RTM. cell
phone.
11. The system according to claim 9, wherein said task is selected
from the group consisting of a single leg stance test, a tandem
stance test, a tandem gait test, a stationary stance test, a static
postural sway test, a dynamic squat test, a single leg squat test,
a step up test, an up and go test, and a jump stability test.
12. The system according to claim 9, wherein said normal range is
determined from at least one previous performance of the task by
the subject.
13. The system according to claim 9, wherein said normal range is
determined from a plurality of performances of the task by a
plurality of comparable subjects.
14-18. (canceled)
19. A system for assessing a subject's postural stability,
comprising: (a) a handheld computing device, comprising: (1) a
three-axis accelerometer, (2) memory, (3) a screen, and, (4) a CPU
in electronic communication with said screen, said three-axis
accelerometer and with said memory, said CPU at least for executing
a plurality of program instructions stored in said memory, said
plurality of program instructions comprising the steps of: (i)
instructing a subject to clasp said handheld computing device
against an upper torso of the subject; (ii) instructing the subject
to perform a task while the handheld computing device is so
clasped; (iii) continuously recording an output of said
accelerometer during the subject's performance of said task,
thereby obtaining a plurality of three-component accelerometer
measurements during the performance of said task; (iv) determining
from at least a portion of said plurality of three-component
accelerometer measurements a JERK score indicium representative of
the subject's postural stability, wherein said JERK score is
calculated according to the equation: JERK = 0.1 * [ i = 2 N X i -
X i - 1 ] , ##EQU00002## where X.sub.i is an instantaneous
acceleration recorded from said three-component accelerometer at
time point "i", where X.sub.i-1 is an instantaneous acceleration
recorded from said three-component accelerometer at time point
"i-1", and, where "N" is the total number of instantaneous
accelerations recorded during said task; (v) using at least said
indicium to determine whether the subject's postural stability is
within a normal range; (vi) if the subject's postural stability is
within said normal range, taking no further action with respect to
the subject; and, (vii) if the subject's postural stability is not
within said normal range, staging an intervention with respect to
the subject.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a divisional of co-pending U.S. patent
application Ser. No. 13/564,401, filed Aug. 1, 2012, which
application claims the benefit of U.S. provisional patent
application Ser. No. 61/514,211, filed Aug. 2, 2011, and
incorporates said applications by reference into this document as
if fully set out at this point.
FIELD OF THE INVENTION
[0002] The present invention relates generally to the field of
balance testing and, more particularly, postural sway and
functional movement analysis as a function of a subject's loss of
vestibular or stability control.
BACKGROUND OF THE INVENTION
[0003] The need for more accurate, accessible and cost effective
assessments of balance and vestibular function are well documented
by researchers and medical professionals. Current field evaluation
tools for balance assessment utilize expensive force platforms,
which are not practical for use in settings other than clinical
research. Force platforms have also been questioned for their
accuracy in the true evaluation of balance. The development of
inexpensive electronic devices that can measure center of mass
(COM) movements to estimate balance have been described in several
clinical research projects, however the application of these tools
within a server connected hand-held mobile device, for the purpose
of evaluating medical conditions has been absent. The typical use
of accelerometers to measure postural sway has been limited to
lower body, waist or lumbar movement analysis and have not been
used to analyze thoracic trunk sway. Thoracic sway presents a
completely different measure of compensatory sway, because it
analyzes above center of mass movement and therefore proprioceptive
balance control of the lower extremity and the trunk without the
false compensation of arm or head movement.
[0004] Balance testing has been identified as an important part of
testing in fall risk prevention in the elderly, in prescription
drug interaction, chronic neurological disease management,
traumatic brain injury, stroke and performance testing in work
readiness screening.
[0005] A multi-faceted approach, that incorporates various types of
movement and postural stability measures, has long been needed to
provide a true analysis of function and stability. Thus, the need
exists for a portable, cost effective balance evaluation tool that
measures the essential components of postural stability with
specific equations developed to quantify changes in multiple
testing conditions, acutely, and over time.
[0006] Heretofore, as is well known in the medical and balance
assessment industry, there has been a need for an invention to
address and solve the disadvantages of prior art methods.
Accordingly it should now be recognized, as was recognized by the
present inventors, that there exists, and has existed for some
time, a very real need for a system and method that would address
and solve the above-described problems.
[0007] Before proceeding to a description of the present invention,
however, it should be noted and remembered that the description of
the invention which follows, together with the accompanying
drawings, should not be construed as limiting the invention to the
examples (or preferred embodiments) shown and described. This is so
because those skilled in the art to which the invention pertains
will be able to devise other forms of the invention within the
ambit of the appended claims.
SUMMARY OF THE INVENTION
[0008] An embodiment of the instant invention is a hand-held
balance evaluation system that employs a novel approach to
measuring upper body compensatory and correctional movements for
purposes of evaluating a subject's balance or dynamic movement
without the need of a harnesses, or fixation techniques. The
instant invention in some embodiments uses only a handheld
computing device that instructs, measures, and analyzes a subject's
motion via an accelerometer that is integral the computing device,
and, in some embodiments, communicates with an external server for
data analysis and live data interaction. Instead of testing
movement in the waist or lower body extremity, which is the
protocol used in any clinical research or previously marketed
device using accelerometers, the instant invention measures
anterior thoracic trunk sway to estimate an individual's balance
using positional change algorithms. By asking the subject to hold
the handheld device to the chest while one or a variety of balance
tests are performed, an embodiment of the instant invention can
determine the amount of sway in the trunk without attached or fixed
monitors, which approach presents a novel protocol, testing device,
and data analysis techniques for assessing postural sway.
[0009] In practice, the instant invention could be used, for
example, on the sideline of a high school, college, professional,
etc., contact sports event such as football. A participant who has
been observed to have been involved in a head-jarring collision can
be provided with the hardware component of the instant invention
and instructed to perform one or more simple movement tests, during
which time the movement will be continuously measured by an
accelerometer. The resulting suite of accelerometer readings are
then used to calculate a coefficient that is reflective of the
amount of postural sway observed during the test(s) which, in turn,
can be compared with previous test scores obtained from the same
individual and/or with population norms based on individuals that
might be of approximately the same age, weight, gender, and/or
physical condition, etc., to determine whether or not the that
individual has symptoms that might be consistent with a concussion
or other head injury. In such a case, the instant invention will
preferably generate a signal that can be read by the sports
participant and/or the coach, etc., which signal will indicate that
further testing for a possible head injury is recommended. In a
sports context, the individual would preferably not return to the
game but instead be directed to report to a location where a
medical diagnosis can be made. In other contexts (e.g., testing for
Alzheimer's' disease, evaluating a patient who might be a fall
risk, etc.) depending on the text results the individual might be
referred to a specialist for more extensive testing.
[0010] The foregoing has outlined in broad terms the more important
features of the invention disclosed herein so that the detailed
description that follows may be more clearly understood, and so
that the contribution of the instant inventors to the art may be
better appreciated. The instant invention is not limited in its
application to the details of the construction and to the
arrangements of the components set forth in the following
description or illustrated in the drawings. Rather the invention is
capable of other embodiments and of being practiced and carried out
in various other ways not specifically enumerated herein.
Additionally, the disclosure that follows is intended to apply to
all alternatives, modifications and equivalents as may be included
within the spirit and the scope of the invention as defined by the
appended claims. Further, it should be understood that the
phraseology and terminology employed herein are for the purpose of
description and should not be regarded as limiting, unless the
specification specifically so limits the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] Other objects and advantages of the invention will become
apparent upon reading the following detailed description and upon
reference to the drawings in which:
[0012] FIGS. 1A, 1B, and 1C illustrate embodiments of the instant
invention as it might be used in practice.
[0013] FIG. 2 contains a program operating logic suitable for use
with the instant invention.
[0014] FIG. 3 contains a high-level schematic illustration of a
hardware component of the instant invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0015] While this invention is susceptible of embodiment in many
different forms, there is shown in the drawings, and will herein be
described hereinafter in detail, some specific embodiments of the
instant invention. It should be understood, however, that the
present disclosure is to be considered an exemplification of the
principles of the invention and is not intended to limit the
invention to the specific embodiments or algorithms so
described.
[0016] An embodiment of the invention is a portable balance
assessment tool that uses a self-contained tri-axis accelerometer,
or other motion detection device, together with an associated
microprocessor or other integrated CPU to measure thoracic body
movement over time in order to evaluate stability. One embodiment
uses single foot stance and tandem gait balance conditions, which
are tested through the use of the instant handheld device, which is
designed to measure parameters representative of compensatory
thoracic sway. An embodiment of the inventive software uses a
mobile application that is resident on an easily held hardware
device (preferably the iPhone in this embodiment) to analyze
movement characteristics of the device, which is securely held at
chest level by a subject. The movements of the device in response
to the subject's tests are analyzed and a "balance score" is
computed as set out below.
[0017] In one embodiment, a cognitive assessment is combined with
balance testing that includes simple and choice reaction times,
working memory/information processing and delayed recall memory,
etc. One goal of the cognitive tests is to assess both left
hemisphere brain function with linguistics and right hemisphere
brain function with information processing. These two test
categories are combined with postural stability assessment
(cerebellum function), to make it possible to more fully estimate
function in all three major brain regions.
[0018] The human body can be divided into three distinct regions
which move independently under unstable conditions: Foot Ground
Contact (FGC), Waist or Center of Mass (COM) and above COM or
Thoracic Sway (TS). Exaggerated force platform readings have been
found during FGC measurements of healthy elite athletes according
to research by the instant inventor. Force platform readings (which
are conventionally known as the postural sway gold standard) showed
more movements, and therefore more instability, in elite athletes
than the normal population. This is likely due to exaggerated foot
compensation in athletes that is used to maintain balance. This
effect appears to be from trained proprioceptive feedback in the
extremities, and increased stabilization in the joints above the
FGC point (Knee, Hip, Lumbar, Thoracic). Compensatory movements in
less balanced subjects appear to occur above the COM, most notably
in the arms, head and trunk. Although these compensatory movements
are most exaggerated in the arms and head, the movements are
asymmetrical and disjointed from the central kinetic chain, making
them unreliable in the evaluation of postural sway.
[0019] COM sway measurements, using accelerometer readings worn at
the waist, are also potentially an ineffective measurement of
postural sway, because the center of mass acts as a fulcrum for
postural movements. Very little motion typically occurs at the COM,
therefore it does not provide the optimal assessment location for
determining changes in postural control.
[0020] One object of the invention in a current embodiment is to
allow "healthy" individuals to establish normal function and retest
following suspected proprioceptive impairment. The development of a
large database of easily accessed, individualized balance scores
will give each user a very accurate baseline or normal score.
Accumulation of users' scores will also help develop population
norms that can be used for comparative analysis.
[0021] An approach to balance assessment software in this
embodiment includes three variables:
a. Location of measurement--The specific body region targeted
(anterior trunk-collarbone to abdomen). The approach of an
embodiment of the instant invention which utilizes accelerometers
for the purpose of postural sway or movement assessment has not
previously been taught. b. Testing Protocol--Testing a subject with
a server connected hardware device securely pressed against his or
her anterior trunk with testing protocols that might include
performance-based tests such as Static Postural Sway, Tandem
Stance, Tandem Gait, Single Leg Stance, Dynamic Squat, Single Leg
Squat, Step up Test, Up and Go Test, Jump Stability. A key element
to the testing protocol is the real time (or near real-time)
sensing, recording, and analysis of data on the testing device
itself to provide instantaneous analysis of the procedure without
computer connectivity or delayed analysis. c. Stability
Algorithms--Finally, the instant invention in some embodiments uses
custom software algorithms to analyze the subject's movement
patterns and issue a balance score.
[0022] An approach according to the instant invention that utilizes
thoracic sway measurements with a handheld device, instead of using
expensive force platforms to measure FCG movements or poorly placed
accelerometers that must be worn or fixated and analyzed later,
presents a preferred way to analyze changes in balance. The
replacement of "worn" accelerometers in poorly placed locations
(waist, head or arms), with software developed for a hand held
device that most users currently own and use daily, makes the
instant approach to balance assessment a superior assessment tool
for low cost administration.
[0023] The assessment of postural stability is performed according
to an embodiment of the instant invention by using proprietary
algorithms that evaluate the instantaneous acceleration readings
that are acquired from an accelerometer (e.g., the LIS302DL MEMS
accelerometer) or gyroscope of the sort that is typically built
into a hand-held devices such as an iPod Touch, an iPod Nano
(4.sup.th and 5.sup.th generation), and a wide variety of cell
phones including the Apple iPhone, certain Blackberry cell phone
models, certain Nokia cell phone models, and many others
[0024] As is generally indicated in FIGS. 1A, 1B, and 1C, in an
embodiment, subjects are instructed to use both hands to clasp the
hand-held accelerometer equipped device 100 against their chest,
after which they will preferably be instructed to perform one task
or a sequence of progressively more difficult balance tests while
the instant Sway Balance system analyzes postural variables via the
accelerometer in the device 100.
[0025] The readings from the accelerometer will then be used to
provide a numerical/quantitative indication of the subject's
balance during the task(s) and, in some embodiments, a
representation of balance on a scale of 0-100 will be obtained. For
example, a test subject might be presented with a drawing FIG. 1A
on the screen of an iPhone and asked to stand for some period of
time on one foot (i.e., a single foot stance). In other instances,
a drawing similar to that in FIG. 1B might be presented to the user
along with the instructions that he remain as motionless as
possible in a standing position. In other instances, the user might
be shown an image like that in FIG. 1C and stand with his feet in
tandem or to walk some number of steps (or for some time period) in
a straight line. In each case, during the test the accelerometer
will be read continuously, with the resulting data used as is
described below.
[0026] Turning next to FIG. 3, a preferred hardware aspect 100 of
the instant invention will include a CPU 105 (microprocessor,
computer chip, etc.) and some amount of volatile or nonvolatile
memory 110 (collectively "memory", hereinafter) into which program
instructions and accelerometer readings may be stored and from
which they may be recalled again. In this embodiment, CPU 105 will
be in electronic communication with a tri-axis accelerometer 115
and with a display device 120 which will preferably be integral to
the device 100. In some embodiments, the display device 120 will be
used to communicate to the subject information such as task
instructions, test results, etc. The inventive device 100 in some
embodiments will include a hardware port 125 to allow electronic
communication with the device 100 when it is docked with a laptop
or desktop, etc. The port 125 might be, by way of example only, a
USB port, a Firewire port, a proprietary interface port (e.g., the
Apple.RTM. iPhone.RTM. 30 pin connector), etc. In other
embodiments, the hand-held device 100 might have a Bluetooth, WiFi,
cell phone, or other communications device to allow the CPU105 to
communicate wirelessly with a remote computer 150.
[0027] In some embodiments the results of previous balance tests
for this same subject can be accessed on the mobile device itself
with an interactive graphical representation of current and
previous scores. Detailed group and organizational analyses can be
accessed through, for example, a web portal that would make it
possible to receive test data and analyze it in order to identify
important trends within a population. The web portal will be
configured to provide a rich database for evaluating the
effectiveness of implemented interventions, the difference between
subjects taking alternative medications, or any potential
differentiator that could have an impact on balance.
[0028] In an embodiment, the measured quantity that is used to
determine the amount of subject movement is referred to as JERK
(m/s3 or g/s), which is the change in acceleration or the
derivative of acceleration with respect to time. This value is used
to estimate the amount of movement, or lack of movement, in order
to determine the stability of the subject. In this embodiment, by
taking the summation of the absolute value of the instantaneous
acceleration at two different time points, a Jerk score can be
computed. In one embodiment, the Jerk score over some period of
time will be calculated via the formula:
JERK = 0.1 * [ i = 2 N X i - X i - 1 ] , ##EQU00001##
where X.sub.i is instantaneous acceleration recorded at time point
"i". That is, X.sub.1 is the initial instantaneous acceleration in
the vertical direction as recorded at a first time point, X.sub.2
is the instantaneous acceleration recorded at some later time time
point "2", etc. In some embodiments, the interval between
successive measurements will be 0.1 seconds, although the selection
of other time intervals (including non-uniformly spaced time
intervals that might be used, for example, to sample more
frequently when the subject is moving more rapidly) is certainly
possible and well within the ability of one of ordinary skill in
the art. In some embodiments N, the number of instantaneous
acceleration measurements, will be 100 and the instantaneous
acceleration will be measured over a period of 10 seconds.
[0029] In a preferred embodiment, the acceleration will be
determined as deviation from the vertical gravity vector of -9.8
m/s.sup.2 or -1 g-force. That is, if the accelerometer (e.g., the
sort of one found in an iPhone) or other measuring device is held
still and completely vertical, the acceleration will be a -1
g-force in the "Y" axis direction due to gravity and 0 g-force for
the X and Z axes. In some preferred embodiments, the instantaneous
acceleration will be adjusted to eliminate the effect of gravity,
which can be assumed to be a constant. Any tilt or movement in the
measuring device will be reflected in a change in the instantaneous
acceleration, which will be represented as a higher JERK value.
[0030] In a preferred embodiment, a recording frequency of 10 hertz
over a 10 second period will provide 99 changes in instantaneous
acceleration, providing 99 JERK scores for each of the three
directional axes (medial-lateral ("ML") or X-axis,
anterior-posterior ("AP") or Z-axis, and superior-inferior ("SI")
or Y-axis). The 99 Jerk scores may be filtered based on a
sensitivity threshold, normalized and sorted for paired samples
comparison, analyzed by taking the sum, standard deviation,
skewness, variability, correlation or any number of other
established statistical evaluation of the data in order to provide
a total stability score for a preferred 10 second test period.
[0031] In some embodiments, an acceleration threshold will be
applied to eliminate "jitter" or small deviations in acceleration
that could be due, for example, to the limits of measurement
accuracy of the accelerometer. That is, depending on the hardware
even if an accelerometer is kept perfectly still (e.g., it is
resting on a table) in some instances it will still report minute
instantaneous acceleration changes. Thus, in some embodiments the
manufacturers sensitivity values that have been reported for MEMS
or other brand accelerometers will be subtracted from each JERK
value to ensure that movement occurring at each point in time is
dependent upon device movement alone and is not biased by potential
sensitivity variations and recording errors. As a specific example,
the device sensitivity of the current version of the iPhone
accelerometer has been reported to be 0.0196 g-force per
measurement and, as such, it might be useful to discard any
measured acceleration changes that are smaller than this number and
to only analyze the values that are more clearly a result of device
movement by the user.
[0032] In some embodiments, following completion of a test battery,
the user will be provided with a balance score based on the
conditions performed, which may be immediately compared to user
selected population normative values. The analysis of normative
data from a live synched server provides a rich database for
comparison of balance scores to self-selected peers. This
interactive database of balance scores is novel in the balance
assessment market, as previous comparison tools use outdated
normative values that do not adjust and do not allow the user to
more accurately compare to their self-selected peer group.
[0033] The balance score set out above has been developed using
motion assessment of all three directional axes and over multiple
conditions for a given protocol. In an embodiment, the single
balance score may be compared with previous test results, which
previous test results can be used to establish a baseline for a
given subject. A baseline might be given as an "overall score" or
average balance score for all baseline tests, and a "normal range"
which will be a provided in some embodiments, which normal range
might be based on the number of tests taken and the variability of
the tests taken previously. In an embodiment, statistical
confidence intervals will be used to establish the normal range
associated with each user. In some cases, to establish an adequate
baseline the subject may be asked to perform four trials of a given
protocol. In some embodiments, the confidence intervals will be
based on data have been acquired from multiple subjects, preferably
subjects that are comparable in some sense (e.g., within the same
age range, participants in the same sporting activity (e.g.,
football players), etc.).
[0034] The "current score" that might be provided to the user will
typically be the most recently administered test score and can be
compared to the "normal range" to determine if it falls outside of
the confidence interval and therefore should be red flagged as a
"likely impaired" test result. Preferably, the subject will be
asked to retake the balance test following a failed test (one that
is outside the normal range) to ensure that the failed test is not
just an outlier.
[0035] Turning next to FIGS. 1A-1C, according to a preferred
embodiment of the instant invention, the drawings depict the
placement of the handheld device in its current embodiment and
three testing protocols (standing sway FIG. 1B, tandem stance FIG.
1C, single foot stance FIG. 1A) that users might be asked to
perform. Users are instructed to place the device against their
chest directly under their collarbone and then perform a balance
test based on a given protocol.
[0036] FIG. 2 contains an operating logic suitable for use with the
instant invention. According to one embodiment, a first step will
be to provide an accelerometer/CPU combination (to include
providing an iPhone or other readily available device) to the
subject (step 205). Broadly speaking there are two instances in
which the subject might be tested. First, the subject might be
tested during a period when he or she is believed to be functioning
normally in order to obtain, for example, baseline measurements
from one or more tests for later comparison with a subsequent test
by the same or a different subject. A second instance when the
subject might be tested, of course, would be in cases where the
subject has experienced some sort of incident or intervention that
might impair that subject's balance.
[0037] Next, preferably the subject will be instructed as to which
test will be performed and how to perform such a test (step 210).
Of course, this step might be delivered verbally by the test
administrator or via instructions delivered via computer (e.g.,
displayed on the face of the cell phone) or printed instructions.
One component of those instructions will be to require that the
subject take the accelerometer in hand and hold it firmly against
his or her upper torso (e.g., chest) as is generally indicated in
FIGS. 1A-1C.
[0038] The accelerometer will then be readied (e.g., the sensing
and recording program might be activated by the test monitor or the
subject) and the subject asked to begin the current test (step
213).
[0039] As the subject performs the test, the instant invention will
continuously read (step 215) values from the three-component
accelerometer that is preferably a part of the measuring device,
where "continuously" means at closely spaced time intervals. As has
been indicated previously, one sample interval suitable for use
with the instant invention is 0.1 second spacing or ten times a
second. Clearly, other sampling intervals (sample rates) could
readily be used and those of ordinary skill in the art will readily
be able to adapt the foregoing when the sample rate is higher or
lower than the examples given herein.
[0040] Next, and preferably, the instantaneous acceleration
(X.sub.i) will be calculated from the three-component measurement
that is a part of the preferred hardware component (step 220).
Next, and preferably, a numerical estimate of the derivative of the
acceleration (JERK) will be calculated. A preferred way to do this
calculation requires at least two successive measurements hence, in
the example of FIG. 2, the derivative step (230) will not be
reached until there are at least two values available to use in the
computation. Note that, although the example of FIG. 2 suggests
that the derivative might be calculated in real (or near-real) time
as the data values are collected, obviously that could be done at
any point including after the testing has been concluded.
[0041] Next, and continuing with the example of FIG. 2, if the test
is not at an end (the "NO" branch of decision item 235), the
preferred operating logic will branch back to the start and begin
data collection again. Otherwise, the numerical value of the JERK
coefficient will preferably be calculated (step 240).
[0042] In some embodiments, the subject may be asked to perform
either a different test or repeat the same test (decision item
245). If that is the case (the "YES" branch of this decision item),
the operating logic will preferably branch again to the top and the
subject will be instructed again, etc.
[0043] Otherwise, the instant invention will preferably analyze and
report the data collected (step 250) and stop. In some embodiments,
as has been discussed previously, the JERK coefficient(s) or a
similar indicium of the user's postural sway and/or stability
during the test(s) will be compared with a baseline measurement for
that same subject or with a population norm. In an embodiment, the
indicium or indicia will be presented to the subject by displaying
a message on display of the instant testing device 100 that
indicates that the subject has been shown to have normal or
abnormal postural stability, as the case may be (e.g., "PASS" or
"FAIL"). In some instances, the JERK coefficient will be reported,
without or with some measure of how it compares with the baseline
measurement or population norm (e.g., the subject's score might be
shown as a point on a standard normal distribution, compared with
the mean/standard deviation of the population, etc.). Those of
ordinary skill in the art will readily be able to devise reports to
communicate the test results to the subject, which test results
might appear on the testing device 100 and/or elsewhere.
[0044] Finally, in some embodiments if the subject's score is
within normal limits (the `NO" branch of decision item 255), the
instant invention will terminate. In some embodiments, users that
are within plus or minus two standard deviations (or three, etc.)
of the average for subjects of the same general type will be
determined to be "normal". In other instances, the subject will be
determined to be "normal" if the currently measured score is within
the range defined by previous measurements of the same subject
(e.g., that subject's baseline measurements).
[0045] Otherwise, (the "YES" branch), when an abnormal,
questionable or out of range score is reported an intervention will
be staged. In the case that the subject is a football player, the
intervention might consist of preventing the player from returning
to the game and sending him or her to a medical station for further
testing to determine whether or not that individual has experienced
a concussion. If the test subject is, for example, elderly, the
intervention might consist of sending the subject to additional
testing for Alzheimer's disease, dementia, etc. Finally, where the
results are questionable (e.g., in instances where the subject does
not understand or refuses to follow instructions), the intervention
might consist of asking the subject to retake the test(s),
determining that the subject is not within normal limits, etc.
[0046] Other potential embodiments of the invention could include
using trunk movement analysis in other stable or unstable
environments that could be static (as described in the single foot
stance of the current invention) or dynamic (as described in the
tandem gait condition). The use of anterior trunk movement analysis
could also pertain to functional conditions such as to evaluate
consistency of training movements (squat, jump, running, cutting)
or detailed analysis of sport specific movements (throwing a
football, shooting a basketball, dribbling a soccer ball, specific
martial arts kicks or punches) where the device may be fixated
instead of held, to the anterior trunk. These examples are by no
means exhaustive, but rather examples of specific movements to
portray intent of evaluation.
[0047] Not only does the further evaluation of movements in sport
present a potential use for this invention, but also balance
evaluation in other populations such as a tool for Alzheimer's
screening, Chemobrain analysis, occupational function screening,
drug and sobriety test, drug and pharmaceutical testing, sports
concussions, physical therapy/orthopedic injury and any other
condition or environment where trunk movement, vestibular function
or balance could be tested.
[0048] Thus, the present invention is well adapted to carry out the
objects and attain the ends and advantages mentioned above as well
as those inherent therein. While the inventive device has been
described and illustrated herein by reference to certain preferred
embodiments in relation to the drawings attached thereto, various
changes and further modifications, apart from those shown or
suggested herein, may be made therein by those skilled in the art,
without departing from the spirit of the inventive concept the
scope of which is to be determined by the following claims.
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