U.S. patent application number 13/311924 was filed with the patent office on 2012-04-19 for method and apparatus for vibrotactile motional training employing cognitive spatial activity.
This patent application is currently assigned to BALANCESENSE LLC. Invention is credited to Karen L. Atkins, Jonathan D. Birck.
Application Number | 20120094814 13/311924 |
Document ID | / |
Family ID | 47351991 |
Filed Date | 2012-04-19 |
United States Patent
Application |
20120094814 |
Kind Code |
A1 |
Atkins; Karen L. ; et
al. |
April 19, 2012 |
METHOD AND APPARATUS FOR VIBROTACTILE MOTIONAL TRAINING EMPLOYING
COGNITIVE SPATIAL ACTIVITY
Abstract
A method and apparatus is disclosed for providing motional
training, such as treatment of disequilibrium and movement and
balance disorders, using cognitive spatial activity and by
providing a subject with vibrotactile feedback in response to an
attempt to perform the spatial activity.
Inventors: |
Atkins; Karen L.;
(Celebration, FL) ; Birck; Jonathan D.; (Portland,
OR) |
Assignee: |
BALANCESENSE LLC
Maitland
FL
|
Family ID: |
47351991 |
Appl. No.: |
13/311924 |
Filed: |
December 6, 2011 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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12201778 |
Aug 29, 2008 |
8092355 |
|
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13311924 |
|
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|
|
60966997 |
Sep 1, 2007 |
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Current U.S.
Class: |
482/142 |
Current CPC
Class: |
A63B 71/0622 20130101;
A63B 2220/836 20130101; A63B 26/003 20130101; A63B 2220/13
20130101; A63B 2220/40 20130101; A63B 24/0062 20130101; A61B 5/486
20130101; A63B 2209/10 20130101; A63B 2220/803 20130101; A63B
2071/0655 20130101; A63B 2024/0096 20130101; G09B 19/0038 20130101;
A63B 2024/0068 20130101; A63B 2208/0228 20130101; A63B 22/18
20130101; G16H 20/30 20180101; A61B 5/1036 20130101; A63B 2071/0663
20130101; A63B 24/00 20130101; A63B 2225/50 20130101; G09B 19/003
20130101; A63B 2230/62 20130101; A61B 5/1116 20130101; A63B
2208/0204 20130101; A63B 2071/0677 20130101; A63H 30/04 20130101;
A63B 2220/18 20130101; A63B 2220/51 20130101; A63B 2225/20
20130101 |
Class at
Publication: |
482/142 |
International
Class: |
A63B 26/00 20060101
A63B026/00 |
Claims
1. A method of providing motional training to a subject,
comprising: (a) providing a force plate having at least one sensor;
(b) providing a controller coupled to the force plate, the
controller being operative to receive input signals from the at
least one sensor and to transmit control signals to a moveable
device; (c) positioning a subject having a center of pressure on
the force plate; (d) shifting the center of pressure of the subject
on the force plate in one or more of forward, rearward and
side-to-side directions, and combinations thereof; (e) receiving
input signals produced by the at least one sensor in response to
step (d); and (f) transmitting a control signal in response to step
(e) which causes the moveable device to move in the same direction
as the shift of the subject's center of pressure.
2. The method of claim 1 in which step (b) includes providing a
controller operative to the transmit control signals to a
radio-controlled vehicle.
3. The method of claim 1 in which step (d) includes beginning with
the center of pressure of the subject at a neutral position
relative to one or more of the forward, rearward or side-to-side
directions, and combinations thereof.
4. The method of claim 3 in which step (f) includes transmitting a
control signal to the moveable device when the subject's center of
pressure shifts to the neutral position which causes the moveable
device to stop.
5. A method of providing motional training to a subject comprising:
(a) providing a force plate having at least one sensor; (b)
providing a controller coupled to the force plate, the controller
being operative to receive input signals from the at least one
sensor and to transmit control signals to a moveable device; (c)
positioning a subject having a center of pressure on the force
plate; (d) shifting the center of pressure of the subject on the
force plate in one or more of forward, rearward and side-to-side
directions, and combinations thereof; (e) defining parameters
within which step (d) may be performed; (f) receiving input signals
produced by the at least one sensor in response to step (d); (g)
transmitting a control signal in response to step (f) which causes
the moveable device to move in the same direction as the shift of
the subject's center of pressure; and (h) providing vibrotactile
stimulation to the subject in the event of a variance between the
input signals and the parameters, the vibrotactile stimulation
being applied at one or more locations on the subject to induce one
or more movements on the part of the subject in order to counteract
the variance.
6. The method of claim 5 in which step (h) comprises providing a
number of vibrotactile actuators each coupled at a different
location on the subject.
7. The method of claim 6 in which step (e) comprises defining the
parameters by determining the maximum extent of shifting of the
subject's center of pressure which is permitted in each of the
forward, rearward and side-to-side directions, and combinations
thereof.
8. The method of claim 7 in which each of the vibrotactile
actuators is associated with the maximum extent of shifting of the
subject's center of pressure in at least one of the forward,
rearward and side-to-side directions, and combinations thereof.
9. The method of claim 8 in which step (h) comprises providing
vibrotactile stimulation from each of the vibrotactile sensors that
are associated with one or more of the forward, rearward and
side-to-side directions, and combinations thereof, wherein the
maximum extent of shifting of the subject's center of pressure is
exceeded.
10. Apparatus for providing motional training to a subject,
comprising: a force plate having at least one sensor, said at least
one sensor being operative to produce input signals in response to
shifting of the center of pressure of a subject positioned on said
first plate in one or more of forward, rearward and side-to-side
directions, and combinations thereof; a radio-controlled moveable
device having a receiver; a controller coupled to said at least one
sensor of said force plate, said controller being operative in
response to receipt of said input signals to transmit control
signals to said receiver thereby causing said moveable device to
move in the same direction as the shift of the subject's center of
pressure.
11. The apparatus of claim 10 in which said at least one sensor
comprises a load cell mounted at each corner of said force
plate.
12. The apparatus of claim 10 in which said radio-controlled
moveable device is a radio-controlled vehicle.
13. The apparatus of claim 10 further including a number of
vibrotactile actuators coupled to said controller, each of said
vibrotactile actuators being adapted to be positioned at different
locations on a subject.
14. The apparatus of claim 13 in which said input signals produced
by said at least one sensor correspond to the direction in which
the center of pressure of the subject is shifted.
15. The apparatus of claim 14 in which the location at which each
of said vibrotactile actuators is positioned on the subject
corresponds to one of said forward, rearward or side-to-side
directions, or to combinations thereof.
16. The apparatus of claim 15 in which said controller is operative
to compare said input signals to a predetermined maximum extent of
shifting of a subject's center of pressure in any one or more of
the forward, rearward and side-to-side directions and combinations
thereof, said controller producing one or more activation signals
in the event of a variance between any of said input signals and
said predetermined maximum extent of shifting of a subject's center
of pressure.
17. The apparatus of claim 16 in which said controller is operative
to transmit an activation signal to each of said vibrotactile
actuators which is positioned on the subject at a location
corresponding to the direction in which shifting of the subject's
center of pressure exceeds said predetermined maximum extent, each
of said vibrotactile actuators when activated being effective to
provide vibrotactile stimulation to a discrete location on the
subject to induce one or more movements on the part of the subject
in order to counteract said variance.
18. Apparatus for providing motional training to a subject,
comprising: a force plate having at least one sensor, said at least
one sensor being operative to produce input signals in response to
shifting of the center of pressure of a subject positioned on said
first plate in one or more of forward, rearward and side-to-side
directions and combinations thereof; a radio-controlled moveable
device having a receiver; a controller coupled to said at least one
sensor of said force plate, said controller being operative in
response to receipt of said input signals to transmit control
signals to said receiver causing said moveable device to move in
the same direction as the shift of the subject's center of
pressure; a number of vibrotactile actuators coupled to said
controller, each of said vibrotactile actuators begin positioned on
the subject at a location corresponding to one of said forward,
rearward or side-to-side directions, or to combinations thereof;
said controller being effective to process said input signals to
determine if there is a variance between the shifting of the
subject's center of pressure and predetermined parameters within
which said shifting is permitted to take place, said controller
being operative to activate one or more of said vibrotactile
actuators in the event of a variance to induce the subject to shift
his or her center of pressure in order to correct said
variance.
19. The apparatus of claim 18 in which said input signals produced
by said at least one sensor correspond to the direction in which
the center of pressure of the subject is shifted.
20. The apparatus of claim 19 in which the location at which each
of said vibrotactile actuators is positioned on the subject
corresponds to one of said forward, rearward or side-to-side
directions, or to combinations thereof.
21. The apparatus of claim 20 in which said controller is operative
to compare said input signals to a predetermined maximum extent of
shifting of a subject's center of pressure in any one or more of
the forward, rearward and side-to-side directions and combinations
thereof, said controller producing one or more activation signals
in the event of a variance between any of said input signals and
said predetermined maximum extent of shifting of a subject's center
of pressure.
22. The apparatus of claim 21 in which said controller is operative
to transmit an activation signal to each of said vibrotactile
actuator which is positioned on the subject at a location
corresponding to the direction in which shifting of the subjects
center of pressure exceeds said predetermined maximum extent, each
of said vibrotactile actuators when activated being effective to
provide vibrotactile stimulation to a discrete location on the
subject to induce one or more movements on the part of the subject
in order to counteract said variance.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation-in-part of U.S.
application Ser. No. 12/201,778 filed Aug. 29, 2008 which claimed
the benefit of U.S. Provisional Patent Application Ser. No.
60/966,997 filed Sep. 1, 2007 under 35 U.S.C. .sctn.119(e) for all
commonly disclosed subject matter. U.S. application Ser. No.
12/201,778 and U.S. Application Ser. No. 60/966,997 are expressly
incorporated herein by reference in their entirety to form a part
of the present disclosure.
FIELD OF THE INVENTION
[0002] The present invention relates generally to systems and
methods for providing a subject with motional training and, more
particularly, to a system and method for providing motional
training, such as treatment of disequilibrium and movement and
balance disorders, using cognitive spatial activity and by
providing a subject with vibrotactile feedback in response to an
attempt by the subject to perform the spatial activity.
BACKGROUND OF THE INVENTION
[0003] Balance, or a state of equilibrium, may be described as the
ability to maintain the body's position over its base of support.
In particular, the optimal posture for controlling balance
typically requires maintaining the body's center of gravity (COG)
within the base of support, such as the support frames defined by
the soles. Balance may be divided into static balance and dynamic
balance, depending on whether the base is stationary or moving.
[0004] Disequilibrium and movement and balance disorders can be
debilitating and increase the potential for fall occurrences. A
movement disorder is a condition that prevents normal movement.
Some movement disorders are characterized by lack of movement,
while others are characterized by excessive movement. A balance
control disorder is typically the result of sensory and/or motor
disorders which impair equilibrium control by a subject. Balance
control disorders may be bilateral, i.e., affect a subject on both
left and right sides, or may only be manifested on one side.
Movement and balance disorders may be caused by disorders in the
vestibular, somatosensory, visual or central or peripheral nervous
systems.
[0005] The vestibular system carries sensory information related to
body equilibrium, specifically roll, pitch, and yaw motion oriented
relative to the direction of gravity. Information is generated by
the semicircular canals and maculae in the inner ear, relayed by
the vestibular nerve to the brainstem vestibular nuclei, and
processed by the vestibular nuclei and mid brain with corresponding
muscular contraction and relaxation known as motor output.
[0006] Aspects of the somatosensory system include: 1) perception
of pressure, vibration, and texture, i.e., discriminative touch, 2)
perception of pain and temperature, and 3) proprioceptive
sensation. Proprioception, which is often referred to more
generally as the somatosensory system, involves awareness of
movement derived from muscular, tendon, and joint articular
surfaces provided by the peripheral nervous system and processed in
the parietal lobe of the brain. These interoception senses provide
internal feedback on the status of the body, indicating whether the
body is moving with required effort and indicating where various
parts of the body are located in relation to each other. Thus,
proprioception involves the essential stimuli provided to, or
received by, skin, joints, and/or muscles to maintain equilibrium
or balance control.
[0007] Damage to any part of the central or peripheral nervous
systems may interfere with postural control of sway necessary for
control of balance. Central nervous system processing includes the
brain primary motor cortex responsible for generating the neural
network impulses controlling execution of movement, the posterior
parietal cortex responsible for transforming visual information
into motor commands, the premotor cortex responsible for sensory
guidance of movement and control of proximal and trunk muscles of
the body, and the supplementary motor area responsible for planning
and coordination of complex movements such as coordinated activity
using two hands.
[0008] In particular, vision plays a significant role in balance.
Indeed, up to twenty percent of the nerve fibers from the eyes
interact with the vestibular system. A variety of visual
dysfunctions can cause disequilibrium. These dysfunctions may be
caused directly by problems in the eyes, or may be caused
indirectly by disorders related to stroke, head injury, vestibular
dysfunction, deconditioning, decompensation, or the like.
[0009] The peripheral nervous system generally relates to the
conduction of sensory information, or messages, from the peripheral
nerves to the brain and spinal cord. For example, such sensory
information may indicate that there is a pressure on the sole of a
foot or that a toe is flexed. Sensory information may also indicate
that the feet are cold or that a finger is burned. Peripheral
neuropathy relates to defects in the peripheral nervous system. In
general, damage to the peripheral nervous system interferes with
the communication of messages to the brain and spinal cord.
[0010] Accordingly, the body relies on the interaction of several
systems to control movement, balance, and posture. For example, the
vestibular system in the ears orient upright stance, especially
when the eyes are closed. The cutaneous, proprioceptive sensory
system feels pressure under the feet. In addition, the joint and
muscle spindles are sensitive to joint position and movement.
Moreover, cognition or brain processing estimates the motor
response magnitude. In sum, balance disorders are predominantly
multi-causal with imbalance occurring due to deficits in more than
one sensory, motor, neuro or cortical pathway.
[0011] The cause and extent of any deficits in a subject's movement
and balance control may be determined by assessing the subject's
ability to control movement and balance while performing a number
of standard functional motor tasks, such as standing still, moving
from a sitting position to a standing position, walking, walking on
steps and uneven surfaces, or the like. This assessment may be
achieved by manipulating sensory input and monitoring motor
response. Quantified sensory assessment, for example, may examine
touch-pressure, two-point discrimination, inner ear response to
warm and cold, or visual acuity by reading the print on an eye
chart. Diagnosis may also be determined qualitatively according to
the observations by an examining physician or a physical
therapist.
[0012] After a balance deficit has been diagnosed and quantified, a
physician may prescribe remedial measures to try and bring the
subject's balance control near or within normal limits. In certain
instances, the physician may prescribe medication that reduces the
action of peripheral senses on the brain or enhance neural network
function. Alternatively, the physician may prescribe a course of
physical therapy, which will typically last at least several
months, with the object of training the subject's brain to deal
with a reduced sense of balance when trying to maintain the body
upright and prevent a fall. Normally, neither of these techniques
will have an immediate effect on the subject's balance deficit.
Moreover, medication can have side effects, and can also reduce the
capability of the brain to process balance information from the
peripheral senses. A traditional course of physical therapy
requires a long training period which may extend over more than two
months. These difficulties and limitations associated with
conventional remedial measures for dealing with balance deficits
are most problematic when the subject is older and likely to have a
falling tendency.
SUMMARY OF THE INVENTION
[0013] In view of the foregoing, there is a need for a system and a
method for rehabilitating disequilibrium and movement and balance
disorders. One or more embodiments of the present invention are
directed to systems and methods for motional training, such as for
the treatment of balance disorders, in which vibrotactile feedback
is provided to the subject in response to an attempt by the subject
to perform predetermined motions. In an alternative embodiment,
motional training is provided using one or more cognitive spatial
activities with or without vibrotactile stimulation as feedback
indicative of the effectiveness of the subject in performing the
spatial activity.
[0014] One embodiment provides a method for providing motional
training to a subject, comprising: providing one or more force
plates each having at least one sensor; positioning a subject on
the force plate(s); identifying a predetermined task for the
subject to perform while positioned on the force plate(s) wherein
the predetermined task is defined by one or more parameters;
receiving signals produced by the at least one sensor in response
to an attempt by the subject to perform the predetermined task;
and, providing vibrotactile stimulation to the subject in the event
of a variance between the signals and the parameters defining the
predetermined task in which the vibrotactile stimulation is applied
at one or more locations on the subject to induce one or more
movements on the part of the subject in one or more directions in
order to counteract the variance.
[0015] Another embodiment provides a system for providing motional
training to a subject, comprising: one or more force plates that
support a subject and provides force-plate-sensor signals while the
subject performs at least one predetermined motion, the
force-plate-sensor signals indicating the results of the attempt by
the subject to perform the at least one predetermined motion; and
one or more actuators that are configured to be coupled to the
subject and that provide vibrotactile feedback to the subject
indicating a variance, with respect to one or more directions,
between the at least one predetermined motion and the results of
the attempt by the subject to perform the at least one
predetermined motion, the one or more actuators being spatially
oriented with respect to the subject to indicate the one or more
directions. The embodiment may further comprise one or more
inertial sensors that are configured to be coupled to the subject
and provide inertial-sensor signals while the subject performs the
at least one predetermined motion, the inertial-sensor signals
further indicating the results of the attempt by the subject to
perform the at least one predetermined motion.
[0016] Still another embodiment of this invention comprises
providing a force plate having at least one sensor; providing a
controller coupled to the force plate which is operative to receive
input signals from the at least one sensor and to transmit control
signals to a moveable device such as a radio-controlled vehicle or
other object capable of movement; positioning a subject having a
center of pressure on the force plate; shifting the center of
pressure of the subject on the force plate in one or more of
forward, rearward and side-to-side directions and combinations
thereof; receiving input signals produced by the at least one force
sensor in response to shifting of the subject's center of pressure;
and, transmitting a control signal in response to the input signals
causing the moveable device to move in the same direction as the
shift of the subject's center of pressure. Vibrotactile actuators
may be located at different positions on the subject, each
corresponding to one of the forward, rearward or side-to-side
directions, or combinations thereof, which may be activated by the
controller in the event the input signals vary from predetermined
parameters of the subject's shifting of his or her center of
pressure.
[0017] These and other aspects of the present invention will become
more apparent from the following detailed description of the
preferred embodiments of the present invention when viewed in
conjunction with the accompanying drawings.
[0018] It is understood that although aspects of the present
invention may be described with respect to the treatment of balance
disorders, embodiments may be applied more generally to any type of
motional training. It should also be evident that the systems and
methods described herein may be used for non-medical activities
such as sports, dance, or specific work task training.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019] FIG. 1 illustrates one embodiment of a motional training
system according to aspects of the present invention.
[0020] FIG. 2 illustrates one embodiment of a vibrotactile belt
according to aspects of the present invention.
[0021] FIG. 3 illustrates an example of vibrotactile feedback that
may be employed according to aspects of the present invention.
[0022] FIG. 4 illustrates another example of vibrotactile feedback
that may be employed according to aspects of the present
invention.
[0023] FIG. 5A illustrates a sub-task in a functional task that is
the subject of motional training according to aspects of the
present invention.
[0024] FIG. 5B illustrates another sub-task in the functional task
of FIG. 5A.
[0025] FIG. 5C illustrates a further sub-task in the functional
task of FIG. 5A.
[0026] FIG. 5D illustrates yet another sub-task in the functional
task of FIG. 5A.
[0027] FIG. 6A illustrates a sub-task in a functional task that is
the subject of motional training according to aspects of the
present invention.
[0028] FIG. 6B illustrates another sub-task in the functional task
of FIG. 6A.
[0029] FIG. 7A illustrates program flow and system logic for
motional training according to aspects of the present
invention.
[0030] FIG. 7B illustrates another program flow and system logic
for motional training according to aspects of the present
invention.
[0031] FIG. 7C illustrates further program flow and system logic
for the motional training according to aspects of the present
invention.
[0032] FIG. 8 illustrates another embodiment of a motional training
system according to aspects of the present invention.
[0033] FIG. 9 illustrates an embodiment of a program flow for
motional training according to aspects of the present
invention.
[0034] FIG. 10 is a block diagram of an alternative method and
apparatus for motional training according to this invention;
[0035] FIG. 11 is a drawing similar to FIG. 7a except of the
embodiment shown in FIG. 10;
[0036] FIG. 12 illustrates forward sway of the subject to produce
forward motion of a moveable device, such as a toy car;
[0037] FIG. 13 is a view similar to FIG. 12 except depicting
rearward sway of the subject;
[0038] FIG. 14 is a view similar to FIG. 12 except depicting sway
of the subject to his right as oriented in the drawing; and
[0039] FIG. 15 is a view similar to FIG. 14 except with the subject
shown with a sway to his left.
DETAILED DESCRIPTION
[0040] Embodiments according to aspects of the present invention
provide systems and methods for providing a subject with motional
training. In particular, embodiments provide motional training by
providing a subject with vibrotactile feedback in response to an
attempt by the subject to perform predetermined motions.
[0041] The set of predetermined motions may correspond to a
functional task, while each predetermined motion corresponds to a
sub-task. The act of moving from a sitting position to a standing
position is a known and well documented functional task. Other
examples include standing, reaching for an object, getting out of
bed, and tasks related to gait.
[0042] The embodiments provide spatial orientation and/or timing
feedback cues via a vibrotactile mechanism to guide postural and
mobility decisions. Real time vibrotactile feedback may be provided
to cue appropriate motions by the subject. In addition, such
feedback may also be used to correct abnormal movement that can
occur during functional tasks. Unlike the prior art, the
embodiments recognize that sensory feedback requirements are
context sensitive, and thus employ vibrotactile stimulation that
may vary by type, location, duration, etc. to provide information
that relates closely to each stage of a the functional activity.
Thus, in some embodiments, the vibrotactile feedback is provided
according to specific, and often well-understood, sub-tasks,
thereby restricting the context and simplifying the control
intelligence.
[0043] For example, the approaches to motional training described
herein may be employed to treat balance disorders. Subjects with
balance disorders may be trained to perform basic functional tasks
and sub-tasks, so that the subjects learn balance strategies and
retain the skills needed to prevent falls. In general, aspects of
the present invention take advantage of the brain's ability to
re-organize and re-learn the functional tasks and sub-tasks. Thus,
embodiments provide a tool by which a subject and a therapist may
determine the limits of stability and understand how the subject
can learn/relearn functional tasks and sub-tasks.
[0044] In addition, embodiments allow such tasks to be scripted
from a set of defined sub-tasks tailored to a subject. In other
words, embodiments provide for the design of new tasks or the
concatenation of different sub-tasks together to define more
complex tasks. Of particular interest are functional activities
that involve transitional motion, i.e., the change from one
motional condition to another. For example, the sit-to-stand task
includes several sub-tasks: sit, upper body lean, transition to
upright stance, and steady upright stance. The sequence from one
stage to the next is transitional and thus requires well bounded
temporal (timing) and spatial (kinematical) conditions to be
achieved.
[0045] Moreover, because the object of clinical treatment is the
transfer of knowledge and experience to the subject during the
treatment, and the retention of transferred knowledge, embodiments
facilitate dynamic modifications to accommodate the special needs
of each subject and to adapt dynamically to challenge the subject
to achieve new skill levels when the subject has mastered a certain
tasks. This dynamic process is believed to be related to brain
plasticity. Thus functional activities, after a training and
evaluation period, may be repetitively practiced in a clinical
setting using an environment that adaptively changes task
difficulty as well as the number of tasks. Some embodiments also
contemplate a take-home system that is programmed with the
characteristics and requirements tailored to specific subjects, at
a specific stage in their training or treatment, allowing subjects
to continue balance training therapy in the home environment.
[0046] Referring now to FIG. 1, a motional training system 10
according to aspects of the present invention is illustrated. The
motional training system 10 is operated by a therapist 40 to
provide motional training for a subject 15. As described
previously, in an example application, the motional training system
10 may be employed to treat balance disorders in the subject 15. As
shown in FIG. 1, the subject 15 is situated on force plates 11a and
11b, while a vibrotactile feedback mechanism 16 as well as optional
inertial sensors 12 and 13 are mounted on, or coupled to, the
subject 15. Meanwhile, another vibrotactile feedback mechanism 42
may be mounted on the therapist 40.
[0047] In general, the motional training system 10 may be operated
with a controller 20, which may be any processing device, such as
an intelligent controller, a conventional desktop computer or the
like, that can execute programmed instructions provided on media,
such as computer-readable memory. A visual display monitor 30 and a
keyboard interface 31 may be connected to the controller 20 to
provide a user interface. The therapist 40 may also operate aspects
of the motional training system 10 via a remote interface 41 as
shown in FIG. 1. The force plates 11a and 11b, the vibrotactile
feedback mechanism 16, and the inertial sensors 12 and 13 may
communicate with the controller 20 via conventional wired or
wireless connections. For example, the force plates 11a and 11b may
communicate directly to the intelligent controller 20 using a wired
connection, such as a conventional universal serial bus (USB)
connection or the like. Meanwhile, a wireless data connection 21,
such as Bluetooth or the like, shown in FIG. 1 may allow the
controller 20 to communicate with the vibrotactile feedback
mechanism 16 and the inertial sensors 12 and 13. In addition, the
remote interface device 41 may also use a wireless interface to
connect to other components of the motional training system 10. In
general, wireless communications may be particularly suitable for
components of the motional training system 10 that must move easily
with the subject 15 or the therapist 40.
[0048] The force plates 11a and 11b provide a technique for
measuring body sway in terms of displacement of the center of
pressure (COP), generated by the inherent instability of the
subject 15 standing on the fixed support surface of the force
plates 11a and 11b. The COP is computed from the signals provided
by force transducers which are typically embedded in the corners
the force plates 11a and 11b. The force transducer outputs are
processed to obtain a projection of the resultant forces acting at
the subject's center of gravity (COG) via the force plates 11a and
11b.
[0049] In general, a force plate is a sensor that measures the load
at discrete points mounted beneath a relatively rigid plate. The
load is usually measured using load-cell type sensors, converted
into an electronic voltage signal and sampled using an analog to
digital converter to be in a form suitable for computer or
microcontroller processing. The response from one or multiple force
plates can be combined using known analog to digital and
mathematical algorithms implemented in computer software. The load
cells and measurement conversion electronics in the embodiment of
FIG. 1 may be configured to be accurate for a range of subject
weights, for example from approximately 100 to approximately 300
pounds.
[0050] Although the embodiment of FIG. 1 illustrates two force
plates 11a and 11b positioned adjacent to each other to form a
combined area, any number and/or configuration of force plates may
be employed to produce an active area that is sufficiently large to
support the subject 15 while standing and/or performing
predetermined motions as described further below. For example, the
combined area of the force plates 11a and 11b may be greater than
approximately 20 inches by approximately 11 inches.
[0051] Although the sensors used in some embodiments may be limited
to the use of force plates 11a and 11b, the embodiment of FIG. 1
also employs the optional inertial sensors 12 and 13. As
illustrated in FIG. 1, the inertial sensor 12 may be mounted
proximate to the center of gravity (COG) of the subject 15, i.e.,
in the area of the lower back of the subject 15. The inertial
sensor 12 may be mounted according to any suitable arrangement. For
example, the inertial sensor 12 may be incorporated with a belt or
garment worn by the subject 15. Alternatively, the inertial sensor
12 may be incorporated into the vibrotactile feedback mechanism 16
worn by the subject 15. Meanwhile, the inertial sensor 13 may be
mounted higher on the upper body of the subject 12, for example at
the back of the neck proximate to the top of the spine. The
inertial sensor 13 may be incorporated in a garment or accessory
worn by the subject 15. Accordingly, the inertial sensor 12
provides information regarding the orientation and motion of the
COG, while the inertial sensor 13 second sensor provides
information regarding the orientation and motion of the upper body
of the subject 15.
[0052] Commercially available inertial sensors are typically
provided with on-board intelligent processing, real-time signal
filtering, and digital interfacing. In particular, each inertial
sensor 12 or 13 may be a three-axis device that employs
accelerometers and magnetometers. In some embodiments, the
three-axis device may combine three-axis accelerometers with a
magnetometer to provide a tilt sensor. In other embodiments, the
three-axis device may employ gyroscopes to provide higher
resolution than the tilt sensors, which are angular rate limited
due to filtering and may be prone to drift.
[0053] The choice of sensor is based on the resolution and costs
constraints. For example, the measurement of spine angle during a
sit-to stand transition will require less resolution in clinical
systems where the primary body orientation is measured using a
force plate sensor. In this example, an accelerometer or low cost
inertial device will provide sufficient accuracy for this task.
However, for a stand-alone inertial sensor, a precision sensor
(i.e. one that includes three axis accelerometers, gyroscopes and
magnetometers) is preferably used.
[0054] There are some advantages in using multiple inertial
sensors, particularly one mounted at the base of the spine and one
just above the shoulder blades as shown in FIG. 1. Multiple sensors
that are interconnected can be used to null some common mode errors
and can be used to more accurately calculate the relative dynamic
motion of the body trunk located between the sensors.
[0055] There are advantages to combining inertial sensors (or
multiple inertial sensors) with a force plate as shown in FIG. 1,
because a more accurate measurement of COG can be performed.
Balance and specifically the limits of balance during dynamic
activities (and especially large postural changes) will result in a
significant mismatch between COG and COP. Trunk and or limb dynamic
movement can be directly measured with an inertial sensor and used
together with force plate data to obtain an accurate estimation of
body orientation and dynamic motion.
[0056] In general, the motional training system includes one or
more sensors that measure appropriate subject body orientation and
approximate the location of the center of gravity. As described in
detail below, sensor information is used together with knowledge of
various functional activities to predict and compare the actual
body response and posture during various stages of each particular
functional task.
[0057] The selection of sensors may depend on whether the system is
a clinical system or a more portable take-home system. In the
clinical environment, a force plate or multiple force plate sensors
is feasible.
[0058] Referring still to FIG. 1, the vibrotactile feedback
mechanism 16 mounted on the subject 15 may include an arrangement
of vibrotactile actuators as well as a controller and battery.
Suitable vibrotactile actuators include the pancake/coin vibrating
motors commercially available from Jinlong Machinery &
Electronics Co., Ltd. of Wenzhou, Zhejiang, China. The actuators
are designed to be wearable on the body and may produce a strong
displacement, i.e., vibration, within the frequency range of
approximately 30 Hz to approximately 300 Hz. As such, the
vibrotactile feedback mechanism 16 uses the sense of touch, i.e.,
the tactile sensory channel, as a technique for conveying
information to the subject 15.
[0059] The sense of touch is processed via the somatosensory (SI)
cortex in the brain. Various cutaneous sensory regions are mapped
to different areas of the SI cortex, making the sense of touch both
intuitive and implicitly linked to motion. In other words, the
sense of touch is intrinsically linked with the neuro-motor
channel, both at the reflex and higher cognitive regions, and is
thus uniquely tied to orientation and localization.
[0060] Accordingly, the actuators of the vibrotactile feedback
mechanism 16 are arranged and coupled to the subject 15, so that
the actuators provide body-referenced, spatial information to the
subject 15. In particular, a direction or motion is mapped to a
specific vibrotactile actuator, so that activation of the specific
vibrotactile actuator and its associated location provide
information with respect to that particular direction or motion.
Motion may be also conveyed with a vibrotactile feedback mechanism
16 by the sequential and timed activation of a series of
vibrotactile actuators, two or more actuators being spatially
oriented with respect to the subject, so that the associated
location and movement of vibrotactile stimulus provide information
with respect to that particular rate and movement direction.
[0061] It has been demonstrated that tactile cueing is
significantly faster and more accurate than comparable spatial
auditory cues and is stable across a variety of body orientations,
even when spatial translation is required. The vibrotactile
feedback mechanism 16 is therefore an intuitive, non-intrusive
feedback mechanism that may be more preferable to visual and audio
cueing. In addition, temporal information can also be conveyed
through the actuators in the vibrotactile feedback mechanism
16.
[0062] The controller 20 can be operated to drive the vibrotactile
feedback mechanism 16 to provide feedback to the subject 15 during
motional training. This feedback may include spatially oriented and
body-referenced information, temporal information, information
based on sequences or patterns of pulses, as well as information
based on vibration frequency. As described previously, the
spatially oriented and body-referenced information may include
directional information based on the location of the vibrotactile
stimulus. The temporal information may be provided according to
pulse timing, where more rapid pulses indicate a greater urgency.
Information based on vibration frequency may be provided according
to high and low frequencies which can be discerned by the subject
15, where frequencies of approximately 250 Hz may, for example,
indicate a greater urgency and frequencies less than 120 Hz may
indicate less urgency.
[0063] The therapist 40 may interface with the controller 20 via
the screen display 30 and the keyboard 31. However, to make it
easier for the therapist 40 to monitor and assist the subject 15
during the motional training, the therapist 40 may alternatively
use the remote interface 41 to control aspects of the motional
training system 10 as described further below.
[0064] In addition, because the vibrotactile feedback mechanism 16
provides information directly to the subject 15 undergoing motional
training, the motional training system 10 may provide the therapist
40 with a similar vibrotactile feedback mechanism 42 as shown in
FIG. 1. so that the therapist 40 can monitor the information that
the subject 15 is receiving.
[0065] An embodiment of a vibrotactile feedback mechanism 16 is
illustrated in FIG. 2 as a vibrotactile belt 55. The vibrotactile
belt 55 may be worn around the torso by the subject 15 as shown in
FIG. 1. The vibrotactile belt 55 includes a plurality of actuators
51 that are spaced equally around a band 53. As described
previously, in one embodiment, the vibrotactile belt 55 employs an
array of eight tactors. For example, eight actuators may be
employed so that when the subject 15 wears the belt, one actuator
51 is centered on the front of the subject 15, e.g., aligned with
the belly button. Correspondingly, another actuator 51 is aligned
with the spine, another actuator 51 is aligned with the right side
of the torso, and another actuator 51 is aligned with the left side
of the torso. When the actuators 51 are oriented in this manner,
each of the eight actuators 51 may represent a direction relative
to the subject 15 similar to the eight major points on a compass,
i.e., east, west, north, northeast, northwest, south, southeast,
and southwest.
[0066] The vibrotactile belt 55, for example, may be formed with a
band 53 of stretch fabric with a fastener 50, which may include a
hook-and-loop fastener, button, zipper, clip, or the like. A wire
52 extends between each pair of actuators 51 and is of sufficient
of length to allow the band 53 to stretch when worn by the subject
15. In particular, the wire 52 may be looped or coiled and mounted
to the belt 55. The actuators 51 are connected to control
electronics 56 via a wire harness 54. The control electronics 56
may include a microcontroller with analog to digital converters,
circuitry for interfacing with sensors, digital-to-analog
converters, and a series of amplifiers. The actuators 51 are
optimized for exciting the tactile response at the skin. In some
embodiments, the actuators 51 are linear actuators.
[0067] This vibrotactile belt 55 may also employ additional
sensors, such as direction sensors (not shown), which operate with
the control electronics 56 and interface with the system controller
20, for example via the wireless data connection 21. Additional
directional sensors may be used to determine the orientation of the
subject 15 with respect to the force plates 11a and 11b to be used
by the intelligent controller in motional tasks described
hereinafter for the determination of vibrotactile feedback 16.
Further, additional directional sensors may be used to determine
the orientation of the subject with respect to the therapist 40 and
to allow the vibrotactile feedback mechanism 42 on the therapist 40
to indicate the position of the vibrotactile feedback mechanism 16
on the subject. The position of the vibrotactile feedback mechanism
16 may be indicated to the therapist 40 in a format that is
independent of or dependent on the orientation of the therapist
40.
[0068] FIG. 3 illustrates a screen display 67 that may be shown by
the controller 20 on the display monitor 30. The screen display 67
provides a view 60 that shows the center of pressure (COP) 63 of
the subject 15 as determined via the force plates 11a and 11b or
derived from combinational sensors. The view 60 also shows a
training region that corresponds to an area in which the subject is
expected to perform a predetermined motion as a part of motional
training on the force plates 11a and 11b. Accordingly, the screen
display 67 may be used to monitor activity by the subject 15 on the
force plates 11a and 11b, and to provide visual feedback to
complement the information provided by the vibrotactile feedback
mechanism 16. In addition, the screen display 67 may be employed to
set parameters or thresholds for operation of the vibrotactile
feedback mechanism 16.
[0069] As FIG. 3 further illustrates, the view 60 also shows
information relating to the vibrotactile feedback mechanism 16. In
particular, the view 60 shows a series of eight segments, or zones,
61 around the perimeter of a representation 64 of the subject 15.
The subject 15 is facing in a direction indicated by the arrow 65
in FIG. 3. Each segment 61 corresponds to an actuator 51 on the
vibrotactile feedback mechanism 16. In the embodiment of FIG. 3,
there are eight segments corresponding to eight actuators on the
vibrotactile feedback mechanism 16. As described previously, the
vibrotactile feedback mechanism 16 may be oriented so that one of
the eight actuators 51 is centered on the front of the subject 15,
another actuator 51 is aligned with the spine, another actuator 51
is aligned with the right side, and another actuator 51 is aligned
with the left side. Therefore, the segment 160 shown in FIG. 3 may
correspond with the actuator 51 on the front of the subject, the
segment 164 may correspond with the actuator 51 aligned with the
spine, and segments 162 and 166 correspond with the actuators 51 on
the right and left sides, respectively. Each segment 61 includes an
are 62 that represents an adjustable threshold for each
corresponding vibrotactile actuator 51. In other words, the width
of the arc 62 as well as the length of the segment 61 may be
configured to set thresholds that determine when the actuators 51
are activated to provide feedback. If, for example, the COP 63 of
the subject 15 moves to a region beyond a segment 61 and arc 62,
the corresponding vibrotactile actuator 51 may be activated. In
other words, when there is a variance between the determined
location of the COP 63, a vibrotactile actuator is activated.
Similarly, in another example a vibrotactile actuator 51 may be
activated until the COP 63 of the subject 15 moves to a
corresponding region beyond a segment 61 and arc 62. Thus, the
segments 61 and arc 62 may correspond to thresholds that define the
boundaries for movement by the subject 15. The thresholds are
selected so that information regarding movement of the subject
relative to these thresholds provides useful information during
motional therapy.
[0070] It is noted that movement of the COP 63 can be caused when
the subject sways, and movement by foot or other significant
movement is not required. As such, the example embodiment
illustrated by FIG. 2 can assess static balance.
[0071] During an example operation of the motional training system
10, the subject 15 attempts to move according to one or more
motions defined as a part of the motional training, e.g., moving
from a sitting position to a standing position to test static
balance. These predetermined motions may make up all or part of a
functional activity. The force plates 11a and 11b react to the
attempt by the subject 15 to move according to the predetermined
motions. In particular, the force plates 11a and 11b determine
corresponding movement of the COP 63 and communicate this
information to the controller 20. As discussed previously,
thresholds may be visually defined on the display monitor 30 via
the controller 20 in terms of segments 61 and arcs 62. In one
embodiment, if the intelligent controller 20 determines that the
COP 63 has moved beyond any of the segments 61 and past any of arcs
62, the controller 20 activates the actuator 51 corresponding to
the segment 61. Thus, the subject 15 receives a vibrotactile
stimulus, or feedback, when there is a variance between the
location of the COP 63 and the segments 61 and the arcs 62.
[0072] Before operation, the COP 63 is initially zeroed, or reset,
to align the axes 66 and the segments 61 over the COP 63. However,
the axes 66 may also be zeroed after a subset of the predetermined
motions during the motional therapy. The therapist 40 may zero the
axes 66 and segments 61, for example, via the therapist remote
interface 41 while monitoring the subject's attempt to perform a
set of predetermined motions. The motional training system 10
allows the subject 15 to sequentially move from one region to
another according to the set of predetermined motions, e.g. from a
sitting position to a standing position and so on. Zeroing allows
to each region, i.e., a subset of the predetermined motions.
Otherwise, the thresholds would only apply to the set of
predetermined motions as a whole.
[0073] FIG. 4 illustrates another view 70 that may be provided on
the screen display 67. The view 70 is also a top view that shows a
representation 64 of the subject 15, a COP 77 of the subject 15, a
target area 71, and navigation limits 72. The COP 77 is initially
zeroed or reset to locate the axes 75 and 79 over the COP 77.
[0074] The predetermined motions corresponding to a functional
activity may require the subject 15, and thus the COP 77, to move
from one area to another. Accordingly, in some embodiments,
vibrotactile cueing may be employed to guide the subject 15 to the
specific target area 71. In particular, using the motional training
system 10, the subject 15 is encouraged via vibrotactile cueing to
move his COP 77 until it reaches the target zone area 71.
Vibrotactile cueing may initially activate the actuator 51 that
corresponds to the segment facing the target 71. The activation of
that actuator 51 causes the subject to turn toward the target area
71. Movement to the target area 71 may require the COP 77 to
traverse an intermediate zone 78. Vibrotactile pulses may be
modulated to indicate the range to the target area 71. For example,
the vibrotactile feedback with a frequency of 250 Hz and duration
of 300 ms may be pulsed initially at 0.1 Hz, pulsed at 1 Hz in the
intermediate zone 78, and then pulsed at 5 Hz when the target area
71 is reached. Alternatively, vibrotactile pulses may be modulated
to indicate the rate at which the COP 77 is approaching the target
area 71. For example, the vibrotactile feedback with a frequency of
250 Hz and duration of 300 ms may be pulsed initially at 0.1 Hz,
pulsed at between 1 Hz and 5 Hz based on the rate of COP 77
movement during movement in the intermediate zone 78, and then
pulsed at 5 Hz when the target area 71 is reached.
[0075] Directional or navigation feedback may also be provided to
the subject 15 using adjacent actuators 51. For example, if the COP
77 shown in the view 70 moves off target, i.e., out of the
intermediate segment 78, into the adjacent segment 73 defined
between segments 72 and 74, the corresponding actuator 51
associated with the segment 73 may be pulsed at a low frequency 15
Hz amplitude modulation to indicate that the subject is off target.
Alternatively, directional feedback can be provided by activating
the actuator 51 that corresponds to the segment 76, which is the
segment on the opposite side of the intermediate segment 78. In
this case, the vibrotactile cueing is provided as a "tether" and
signals the subject 15 to move in the direction of the vibrotactile
stimulation. As shown in the view 70, the representation 64 of the
subject 15 positioned in the segment 73 would be drawn back to the
segment 78 as the representation 64 moves toward the segment 76 in
response to the activation of the actuator 51 corresponding to
segment 76.
[0076] Further vibrotactile feedback can be communicated to the
subject 15 to indicate to the subject is that the target area 71
has been reached. This vibrotactile feedback, for example, may
include pulsing two front actuators 51 alternately, and then
pulsing one back actuator 51. The subject 15 may learn the various
messages associated with the vibrotactile feedback before the start
of the motional training.
[0077] Once the target 71 has been reached, the therapist 40 may
also elect to move the axes 79 and 76 to the new location 71 and
revert to the view 60 as shown in FIG. 3. Alternatively, the
therapist may elect to guide the subject to a new target. Indeed
the new target may be the initial starting position.
[0078] Embodiments of the present invention may be employed to
treat stroke subjects with Pusher Syndrome. These subjects suffer
from disturbed body orientation that drives both conscious
perception of body orientation and abnormal muscle activation
patterns or synergies. For example, subjects with Pusher Syndrome
may perceive that their bodies are oriented in an upright position
when in fact their bodies may be leaning by as much as 20 degrees
towards the side of the brain lesion. When sitting or standing, the
nonparetic extremities push lateral balance to the hemiparetic
side. The phenomenon is present in approximately 79% of all acute
strokes that resolves to 10% by 6 months (early intervention may
eliminate Pusher Syndrome altogether), and is present in both left
and right sided CVA. Subjects with Pusher Syndrome may have a
normal perception of visual vertical, but they may be unable to
perceive that their body posture may be leaning severely.
Observations suggest that Pusher Syndrome affects the neurological
pathway that is integral to sensing orientation of gravity and
controlling upright body posture.
[0079] Treatment of subjects with Pusher Syndrome can be achieved
by employing the vibrotactile feedback mechanism 16 to provide the
subject a reference for body-orientation. If the subject shows a
tendency to lean to a particular side, the length of the segment
arc 62 corresponding to the opposite side is adjusted to be closer
to the COP 63. The vibrotactile feedback mechanism 16 is set to
activate the corresponding actuator 51 if the COP 63 moves over a
particular segment arc 62. For example, if a subject leans to the
right, segment 166 on the left side as shown in FIG. 3 is defined
to provide a smaller threshold relative to the COP 63. In the
normal maladapted stance, the subject feels vibrotactile feedback
on the left side unless the subject leans further towards the
right. The therapist can therefore use the invention to provide an
additional sensory feedback reference which can be used for
neurological retraining. A similar effect can be achieved using the
technique described with reference to FIG. 4. In this case, a
target 71 is configured on the left hand side of the subject, e.g.,
on axis 75, and used as a goal for the subject to shift their
weight from the initial maladapted state 77 towards postural
correction. In each example, the therapy may be practiced and
repeated over several sessions, including various other tasks to
enrich and diversify the learning environment. The therapist 40 may
also adapt the segment thresholds and target locations in each of
the examples, based on the subject performance during this
task.
[0080] FIGS. 5a, 5b, 5c and 5d depict an example of a sequence of
predetermined motions that define a functional transitional
movement task. The transition from a sitting position to a standing
is an extremely important functional activity. FIGS. 5a, 5b, 5c and
5d illustrate the sub-tasks that make up this functional task. The
motional kinematics for this particular functional task are
described by Patrick D. Roberts and Gin McCollum (Dynamics of the
sit-to-stand movement, Biological Cybernetics, Volume 74, Number
2/January, 1996). This reference shows that some of the sub-tasks
may be conditionally stable or unstable. The embodiment provides a
technique for guiding the subject 80 through the sequence of
sub-tasks and providing feedback to the subject 80 to help the
subject 80 complete the functional task. The embodiment further
provides a technique for repetitively guiding the subject 80
through a sub-activity to help the subject 80 learn the
sub-activity.
[0081] FIG. 5a shows a subject 80 initially at rest in a sitting
position on a chair 81 disposed on a force plate 82. The subject
wears a vibrotactile belt 106 around his torso. An inertial sensor
103 may be mounted at the lower back of the subject 80 and an
inertial sensor 84 may be mounted at the upper shoulder of the
subject 80 to provide additional information. Specifically, the
spine angle, bend and other postural information from the inertial
sensors 103 and 84 may be helpful in determining subject
transitional motion characteristics.
[0082] FIG. 5a also shows a corresponding top view 83 of the force
plate area. The view 83 may also be shown as a screen display on
the display monitor 30, and may be used by the therapist 40 to
monitor activity and/or configure a training region. In addition,
the view 83 may provide visual feedback that complements the
vibrotactile feedback received by the subject 80. The subject is
orientated to face in the direction shown by arrow 100. The chair
takes up an area 88. While seated, the subject COP 87 is located
within the chair area 88. System axes 104 and 85 are initially
defined to coincide with a static stable seating. It should be
noted that the COP data and vibrotactile belt 106 can easily be
used to provide the subject 80 with postural feedback while seated.
If the COP 87 moves outside a predefined segment, i.e. a variance
occurs; the corresponding body referenced tactile transducer can be
used to alert the subject 80 to correct his or her posture. In this
case, the limits of the segment need to be close to the axes 85 and
104 as the excursion of a subject's COP 87 during sitting is
relatively small.
[0083] FIG. 5b shows the next sub-task in the sequence. In
particular, the subject 80 moves from the sitting position on a
chair 81 to an upper body forward lean position 97. The subject 80
is guided into the lean position 97 by the intelligent controller
20 based on measurement of the patient 80 COP 87 and sensor
information. In particular, the intelligent controller 20 may
provide vibrotactile cueing by activating the actuator of
positioned at the front of the subject 80.
[0084] FIG. 5b shows a corresponding top view 83 of the force plate
area. The subject 80 is orientated to face in the direction shown
by arrow 100. The COP 89 of the subject 80 is shown with axes 85
and 104. It is desirable to guide or cue the subject 80 to move his
COP 89 onto a target area 90. During the process of translating the
COP 89 towards the target area 90, it is also desirable that the
COP 89 stay within moving bounds 91 and 92. If the COP moves
outside the bounds 91, vibrotactile feedback is then applied to the
subject to correct the translation. The target region 90 may be set
to shapes other than a circle, such as a rectangle, and may be
positioned off the axis 104 to counter any subject asymmetrical
tendencies.
[0085] FIG. 5c shows the next further sub-task in the sequence. In
particular, the subject 80 transitions to an initial stance 96
after moving from a sitting position on the chair 81. An additional
vibrotactile feedback mechanism 107 may be mounted on the subject's
upper body. Lean is no longer encouraged and the subject 80 is
guided to a stable balance by the intelligent controller 20 by
providing vibrotactile cueing. The subject 80 is also guided to
regain upright posture. The sensors 84 and 103 may be used to
determine the spine trunk lean angle and provide this information
to the controller 20. The controller 20 then provides vibrotactile
feedback 106, preferably via a pattern of vibrotactile signals
representing a message. Alternately an additional vibrotactile
feedback 107 can be used to provide directional cueing i.e. a
vibrotactile stimulus on the neck, shoulders or upper body to guide
the subject 80 to move towards the stimulus and regain upright
stance. A tactile message is thus a reminder to the subject 80 and
eliminates the need for a verbal instruction.
[0086] FIG. 5c shows a view 83 of the force plate area. The subject
is orientated to face in the direction shown by arrow 100. The COP
94 is aligned with axes 104 and 85. When compared to the initial
position of the axes shown in FIG. 5a, these axes have shifted in
the direction of the arrow 100. Vibrotactile feedback can be
applied to the subject 80 according to the technique described with
reference to FIG. 3. Various segments 95 represent areas beyond
which a body referenced vibrotactile signal is applied to indicate
to the subject that the threshold has been exceeded in a particular
zone, i.e., a variance has been created.
[0087] FIG. 5d shows the subject 80 who has attained an upright
stance 102. The forward lean no longer exists and the subject 80 is
now be assisted in quiet stance. The controller 20 provides
vibrotactile cueing 98 when the COP 94 moves beyond the defined
thresholds. The inertial sensors 84 and 103 may be employed to
confirm spine angle. The inertial sensor 84 may also provide
heading (or trajectory) information to the controller 20 and
provide corrective feedback if the subject is not facing in the
direction of the arrow 100.
[0088] FIG. 5d also shows a corresponding view 83 of the force
plate area. The subject faces in the direction shown by arrow 100.
The axes 85 and 104 coincide with the initial location of the COP
94. Similar to view 60 of FIG. 3, the view 83 shows a series of
segments 95 that indicate the thresholds for movement of the COP 94
and determine when the appropriate vibrotactile actuator is
activated.
[0089] FIG. 5e illustrates another sub-task in the sit-to stand
functional task. After completing the sub-tasks described
previously, the subject 80 now performs a full body turn to the
right and resumes a stable stance. The subject 80 is guided through
a turn to the right through vibrotactile cueing. In particular, one
or more actuators on the right side of the subject 80 are activated
to initiate a turn to the right. The inertial sensor 103 may
provide heading data to the controller 20.
[0090] FIG. 5e also shows the corresponding view 83 of the force
plate area. The subject faces in the direction shown by arrow 101.
The vibrotactile belt 98 is orientated in the direction that the
subject is facing, so that the front segment now corresponds with
the segment 105 shown in the view 84. Similar to the view 60 of
FIG. 3, the view 83 shows a series of segments 95 that also
indicate the thresholds for movement of the COP 94 and determine
when the appropriate vibrotactile actuator is activated.
[0091] Referring now to FIG. 6a, an example of a functional task
110 is illustrated where a subject 111 stands on a force plate 113
and reaches for a target object 116. The vibrotactile belt 112
provides feedback to guide the subject 111 through the task 111.
The corresponding top view 114 also shown in FIG. 6a is similar to
the view 60 of FIG. 3. The view 114 shows a series of segments 120
that indicate the thresholds for movement of the COP 120 and
determine when the appropriate vibrotactile actuator is activated.
Alternatively, the view 114 may be employed to provide vibrotactile
cueing which guides the subject 111 through the necessary sub-task
movements with the vibrotactile belt 112.
[0092] FIG. 6b illustrates the subject 111 reaching for the target
object 116 while standing on a force plate 113. Inertial sensors
117 and 130 may provide additional information about bend angle and
posture. A controller 20 uses the force plate 113 and sensor
information to provide sub-task specific vibrotactile feedback to
the subject 111 with the vibrotactile belt 112.
[0093] FIG. 6b also shows the corresponding top view 114 with the
subject 111 facing in direction 131. Similar to the view 60 of FIG.
3, a series of segments 132 indicate the thresholds for movement of
the COP 120 and determine when the appropriate vibrotactile
actuator is activated.
[0094] FIGS. 7a, 7b, and 7c show program flow and system logic for
the motional training system 10. The program flow includes three
main routines; a test shown in FIG. 7a for new subjects to
determine whether they will be suitable candidates for vibrotactile
guided training, a scripting routine, and configuration tool for
therapists trainers to design their own functional movement tasks
as shown in FIG. 7c and a series of functional movement tasks as
shown in FIG. 7b. The functional tasks 274 include tasks and
sub-tasks, sensor measurements, processing, visual and vibrotactile
feedback data, adaptive changes to the tasks and feedback
parameters, database storage, and retrieval of information. A
feature in the operation of the program and system is the ability
to adapt the task for the subject and also adapt the vibrotactile
thresholds and feedback. These adaptations are completed
automatically by the system using an assessment of the subject
performance in the task.
[0095] FIG. 7a illustrates the program control logic for a test 250
and a start-up step 251 for the determination of subject or user
suitability for vibrotactile guided motional training. Subject data
is either selected or entered at step 262. A database 252 is
employed to store, retrieve and collect subject information as well
as specific components and data related to vibrotactile guided
motional training activities. New subjects undergo initial training
at step 263, e.g., a therapist shows the subject how the
vibrotactile actuators activated during movement by the subject. In
particular, the segment thresholds as described previously are set
to cause activation of particular actuators when the subject moves
his COP in a corresponding direction for defined distances or
thresholds as described hereinbefore. The subject is instructed,
for example, to lean to the side and activate a corresponding
vibrotactile actuator in step 264. If the subject fails to comply
or is unable to reach the threshold to activate the particular
actuator within a time threshold 254, e.g., approximately about 5
seconds, the system may alert the therapist and move the threshold
for activation closer to the COP. The time threshold may be
normalized for subject age and ability. If the subject is able to
activate the particular actuator, however, the subject is then
instructed to move and activate another actuator in step 255. Each
subsequent activation of a particular vibrotactile actuator should
also be activated within a similar time threshold 256, to that set
during the initial movement test 254. If the subject fails to
activate 50% of the actuators, for example, at a default threshold
261, the system may determine in step 257 that the subject is not
suitable for vibrotactile guided training. Subjects who are able to
show sufficient competence may move onto other functional tasks in
step 258.
[0096] FIG. 7b shows the program control logic for vibrotactile
guided motional training 270. The therapist may employ two modes: a
program scripting mode 271 and a subject activity mode 272. The
program scripting mode 271 allows the therapist to configure and
program new functional tasks that are stored in a system database
252. The subject activity mode 272 may use this database 252.
Vibrotactile guided motional training may include sub-tasks 273,
which may be defined according to the types of vibrotactile
feedback techniques described with reference to FIG. 3 or 4. The
particular vibrotactile feedback mode and sub-task 273 may be
chosen by the therapist for subject task activity 275. Sub-task
vibrotactile guided training is completed to ensure that the
subject masters and practices the necessary mobility skills for
functional tasks.
[0097] The definitions of the functional tasks and sub-tasks,
together with subject data, and user defined parameters are stored
in a system database 252 and may be accessed 279 for the selection
of a functional task 274. The system also permits multiple tasks
275 to be concatenated to create more complex functional task
sequences. Once the task 274 and task combination have been
selected, the functional activities are commenced 276. Depending on
the activity the therapist may adjust various parameters for task
or sub-task performance based on a visual assessment of the
subject. For example, the therapist may change a threshold to
encourage a subject to lean in a reach task. In other embodiments,
the functional activity may be programmed to automatically adapt
based on the context and performance of the subject in a particular
set of tasks. Activities may be repeated 277 until completion 278.
The performance of the subject during the functional activities may
be stored for later evaluation and assessment in database 252.
[0098] FIG. 7c illustrates the program control logic for defining
and scripting motional tasks 290. The sensor thresholds as well as
the vibrotactile feedback may be configured by the user or
therapist for a particular activity or adapted for the specific
needs of a subject. In multiple or complex tasks, the display may
migrate from one mode to another as described hereinbefore. Tasks
can be either set to default 281 or programmed to therapist defined
parameters 285. The functional tasks can be chosen from a menu of
standard activities 282 or be user defined 285. Multiple tasks may
be concatenated and stored in the database 252. In user selected
functional activity scripting, it may also be further desirable to
select 285 timing, temporal, vibrotactile and display. Further,
adaptation of the vibrotactile, display and timing thresholds may
be selected 287. Adaptation criteria may be based on the subject's
performance during the scripted motional activities and the subject
achieving user defined metrics. For example, the pre-defined
sensitivity thresholds for a functional activity, such as that
described in FIG. 3, can be adapted at a user determined rate,
based on how quickly and how often a vibrotactile display threshold
is reached.
[0099] FIG. 8 shows a motional training system 120 on a subject
121. Sensors 125, 126 and 127 may be used to provide postural and
gait information to an intelligent controller 124. The user can
select various functional tasks and program modes via a wrist
display 122 or in an alternate embodiment, the intelligent
controller 124 may preempt the subject and recognize a limited set
of functional activities. Sensor signal gesture recognition
algorithms can be used for this purpose. User assistance during
dynamic tasks is provided by a vibrotactile belt 123, controlled by
the intelligent controller 124. In another embodiment of this
invention, the transitional motion assistive device 120 may be
configured with limited sensors or even without sensors. In this
configuration the activities are cued in open loop i.e. the system
acts to provide subject specific temporal, body referenced cues. In
all embodiments, it is anticipated that the therapist programs
subject specific parameters into the intelligent controller
124.
[0100] FIG. 9 shows a program flow diagram 370 for motional
training. The program flow includes the step 360 of measuring a
suite of sensors to obtain body kinematics information, for example
COP and COG. A database 361 is pre-programmed to contain subject
data and subject specific parameters, such as timing data, subject
needs, specific cueing information and vibrotactile thresholds. The
database 361 may also contain a set of gesture recognition
parameters that are associated with a particular subject's movement
parameters during previous motional activities. Subject functional
movement tasks 362 may be either automatically recognized by the
movement patterns determined from the sensor measurements 360 using
the intelligent processor, or input by the subject or therapist
using an interface device, for example a remote interface device 41
or wrist display 122 as described hereinbefore. Thus, the system
knows what task 363, e.g., sit-to-stand, reach, walk and turn, or
other pre-defined task, is being performed. The therapist enters
subject specific parameters 373 into the database 361. The system
thus uses the subject specific parameters stored in the database
361 to determine vibrotactile feedback display parameters.
Vibrotactile guided motional assistance during specific tasks
provided 364. The subject's performance during the functional
activity tasks may also be measured and stored 374 in the database
361, allowing adaptive re-programming of the assistive steps as
well as a record of subject compliance with the established
protocols. Analysis of the database can be performed in real time
by the therapist, or stored for subsequent downloading. Downloading
and analysis may also be completed remotely using the internet and
related approaches.
[0101] Referring now to FIGS. 10-15, an alternative embodiment of
the method and apparatus of this invention is shown. In the
embodiments described above in connection with a discussion of
FIGS. 1-9, directional or navigation feedback is provided to the
subject 15 in response to an attempt to perform a selected activity
such as stand, sit-to-stand, reach, bend, walk and turn,
bed-to-stand, squats and others. In order to enhance subject
interest and avoid the tedium that can arise from repetitive
motions, it is desirable to incorporate cognitive spatial
activities in the rehabilitation process. Certain features of the
embodiment of FIGS. 10-15 are common to those described in FIGS.
1-9, and the same reference numbers are therefore used in FIGS.
10-15 to identify common structure.
[0102] As schematically illustrated in FIG. 10, the motional
training system 400 of this embodiment includes a system controller
402, a moveable device controller 404, a force plate 406, a
moveable device 408 and a vibrotactile feedback mechanism 16. The
vibrotactile feedback mechanism 16 preferably comprises a
vibrotactile belt 55 having a number of vibrotactile actuators 51
as described above in connection with a discussion of FIGS. 1 and
2. The vibrotactile feedback mechanism 16 is preferably connected
to the controller 402 via a wireless data connection, represented
by line 410 in FIG. 10, such as Bluetooth or the like. The force
plate 406 may comprise two plates 11a and 11b as shown in FIG. 1,
or a single plate, which preferably communicates directly with the
controller 402 via a wired connection such as a universal serial
bus (USB) 412. The force plate 406 (or plates 11a, 11b) is
essentially a sensor that provide a means for measuring body sway
in terms of displacement of the COP of a subject 15 standing on the
force plate 406. Preferably, the force plate 406 includes a
load-cell type of sensor 414 mounted at each corner which
collectively measure load applied by the subject 15 and convert it
into an electronic voltage signal which is sampled using an
analog-to-digital converter to be in a form for processing by the
controller 402. See also FIGS. 12-15.
[0103] The system controller 402 may be any processing device, such
as a conventional desktop computer, capable of executing programmed
instructions provided on media such as computer-readable memory.
The controller 402 may be coupled via a USB connection 416 to the
moveable device controller 404 or any other suitable connection. In
the illustrated embodiment, the moveable device 408 is depicted in
FIGS. 12-15 as a radio-controlled car 418 whose operation is
controlled by a conventional radio frequency (RF) controller
identified as the moveable device controller 404 in FIG. 10. As is
well known in the art, so-called radio controlled cars are
self-powered model cars, typically including small electric motors
powered by rechargeable batteries, which include a receiver that is
responsive to an RF signal from a transmitter contained in the RF
controller. Depending on the complexity of the RF controller, its
transmitter is effective to send signals to the receiver in the toy
car causing it to move forward, to move rearward, to turn left, to
turn right or to execute combinations of these directional
movements.
[0104] In the embodiment illustrated in FIG. 10, the system
controller 402 and moveable device controller 404 are depicted as
separate components coupled to one another via a USB connection
416. A wireless connection, shown as line 420 in FIG. 10, couples
the moveable device controller 404 to the moveable device 408. It
is contemplated that the system 400 of this invention may be
adapted for use with essentially any type of "moveable device,"
e.g. toy vehicles, toy animals and the like, and the toy car
depicted in FIGS. 12-15 is for purposes of illustration only.
Further, since different types of moveable devices may be employed
with the system 400, it is desirable to use the device controller
sold with a particular moveable device and couple it to the system
controller 402. However, it should be understood that the moveable
device controller 404 may be incorporated into and made an integral
part of the system controller 402, if desired.
[0105] The operation of the system 400 is illustrated with
reference to FIGS. 11-15. Initially, as shown in FIG. 11, a test
routine may be performed on the subject 15, which is similar to
that described in connection with a discussion of FIG. 7a, to
determine if he or she is a suitable candidate for cognitive
spatial activities. A start-up step 424 is followed by the
selection or inputting of subject data represented by box 426. The
subject data may be stored, retrieved and collected from a database
428. Once the subject data is entered, the system 400 determines
whether the subject is "new," or has participated in the cognitive
spatial activity previously, as represented by box 430. The subject
may proceed to the activity if he or she has done so previously, as
denoted by box 432. If the subject is new, however, he or she is
given instruction regarding how to create movement of the car 418,
as explained below, within parameters determined by the therapist.
See box 434. After attempting the cognitive spatial activity,
denoted as a "skill test" in box 436, subjects are either
characterized as not suitable for this type of therapy, as at box
438, or they are permitted to continue to the performance of such
activity. See box 440.
[0106] As noted above, the force plate 404 (or plates 11a, 11b)
employed in the system 400 of this embodiment provides a means for
measuring body sway in terms of displacement of the COP of a
subject 15 standing on the force plate 404. This feature of the
invention herein is employed to control the movement of the car 418
in each of a number of directions, i.e. forward, rearward,
side-to-side and combinations thereof. Preferably, when the subject
15 stands in an upright or neutral position, the system controller
402 is operative to cause the moveable device controller 404 to
transmit a "stop" signal to the car 418 so that it remains in a
fixed position. In response to motion of the subject 15 in a
forward direction, i.e. in the orientation of the subject 15 as
depicted in FIG. 12, the sensors 414 associated with the force
plate 406 send an input signal to the system controller 402
representative of a shift in the COP of the subject 15 in the
forward direction. The "motion" of the subject 15 in this context
refers to a leaning or swaying motion in the forward direction. The
system controller 402, in turn, directs the moveable device
controller 404 to transmit an RF control signal to the receiver in
the car 418 which causes it to move in the forward direction
represented by arrow 442 in FIG. 12. Forward motion of the car 418
ceases when the subject 15 returns to the neutral position.
Similarly, the car 418 may be moved in a rearward direction,
denoted by the arrow 444 in FIG. 13, in response to swaying motion
of the subject 15 in the rearward direction.
[0107] Viewing the car 418 in the same direction as would the
subject 15 standing on the force plate 404, as illustrated in FIGS.
14 and 15, the car 418 may be controlled to make a right-hand turn
represented by arrow 446 when the subject 15 leans or sways in a
side-to-side direction to his or her right, or to make a left-hand
turn denoted by arrow 448 when the subject leans or sways in a
side-to-side direction to his or her left. The system controller
402, moveable device controller 404 and car 418 all function in the
same manner as described above in connection with discussion of
FIG. 12 to effect the rearward motion, a right-hand turn and a
left-hand turn of car 418 schematically illustrated in FIGS.
13-15.
[0108] Additionally, if permitted by the software in the moveable
drive controller 404, the car 418 may be made to move in directions
that combine forward motion, rearward motion, a right-hand turn
and/or a left-hand turn shown in FIGS. 12-15. By analogy to the
points of a compass, and assuming the front of the subject 15
corresponds to a "northerly" direction, the car 418 may be made to
move in a generally northeasterly direction, for example, when the
subject 15 leans or sways in a forward direction and to his or her
right at the same time. Similarly, the car 418 may be moved in a
generally southwesterly direction by a combined movement of the
subject 15 in a rearward direction and to his or her left.
Northwesterly and southeasterly movements of the car 418 are also
possible by combined movement of the subject 15 forward and to his
or her left, and rearward and to his or her right,
respectively.
[0109] It is contemplated that the therapist may begin
rehabilitative activities employing the system 400 of this
invention by instructing the subject 15 to perform simple forward
and rearward movements of the car 418 and/or right-hand and
left-hand turns. As the subject 15 progresses in his or her
therapy, and if space permits, the therapist may choose to create a
"course" on which the car 418 must be "steered" by the subject 15.
Any number of different variations or how the subject 15 may be
tasked with moving the car 418 may be employed by the therapist to
add variety, interest and a measure of enjoyment to the
rehabilitation process using the system 400 of this invention.
[0110] While the system 400 may be operated without a vibrotactile
actuator mechanism 16, it is believed that particularly for
subjects 15 who are relatively early on in the rehabilitation
process it is advisable to equip them with a vibrotactile belt 55
having a number of vibrotactile actuators 51. In the same manner
described in connection with a discussion of FIG. 3, the system
controller 402 may be configured by the therapist to create a
series of eight segments or zones 61 each corresponding to one of
eight vibrotactile actuators 51 mounted on the vibrotactile belt 55
which may be worn around the torso of the subject 15. Each segment
61 includes an are 62 that represents an adjustable threshold for
each corresponding vibrotactile actuator 51. The width of each arc
62, and the length of each segment 61, collectively define
parameters within which the subject 15 is permitted to move without
exceeding the threshold at which a corresponding vibrotactile
actuator 51 is activated. Preferably, in response to input signals
from the force plate 404 representative of the shift of the COP of
a subject 15 in effecting motion of the car 418, the system
controller 402 functions to compare such signals to the parameters
noted above. In the event of a variance between such parameters and
the actual swaying or leaning movement of the subject 15 in
attempting to move the car 418, the system controller 402 is
operative to send an activation signal to the associated
vibrotactile actuator 51 to alert the subject 15 that he or she has
exceeded the permissible extent of movement. For example, if a
subject 15 leans to far forward in an effort to produce forward
motion of the car 418, the system controller 404 sends an
activation signal to the vibrotactile actuator 51 located at the
front of the subject 15 thus inducing he or she to lean in the
opposite, rearward direction in order to avert a loss of balance or
a fall.
[0111] While the invention has been described with reference to a
preferred embodiment, it should be understood by those skilled in
the art that various changes may be made and equivalents
substituted for elements thereof without departing from the scope
of the invention. In addition, many modifications may be made to
adapt a particular situation or material to the teachings of the
invention without departing from the essential scope thereof.
[0112] For example, the connections between components of the
apparatus illustrated in FIGS. 10-15 are described above as being
wired or wireless. It should be understood that each of these
connections could be either wired or wireless and the invention is
not intended to be restricted to one or the other.
[0113] Therefore, it is intended that the invention not be limited
to the particular embodiment disclosed as the best mode
contemplated for carrying out this invention, but that the
invention will include all embodiments falling within the scope of
the appended claims.
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