USAARL Report No. 2011-01
Initial Consideration of the Feasibility and
Optimal Application of Tactile Sway Cueing
to Improve Balance among Persons Suffering
from Disequilibrium
By Angus H. Rupert
Benton D. Lawson
United States Army Aeromedical Research Laboratory
Warfighter Performance and Health Division
November 2010
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Initial Consideration of the Feasibility and Optimal Application of Tactile
Sway Cueing to Improve Balance Among Persons Suffering from
Disequilibrium
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6. AUTHOR(S)
Angus H. Rupert
Benton D. Lawson
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U.S. Army Aeromedical Research Laboratory
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USAARL 2011-01
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USAMRMC
U.S. Army Medical Research and Materiel Command
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14. ABSTRACT
This report explores the use of tactual sway cueing as a compensatory strategy for patients suffering disequilibrium. Sway feedback
systems have the potential to aid Soldiers with traumatic brain injury (TBI) and other patients whose balance has been disrupted by
concussions, labyrinthine diseases, or aging. Several sway feedback approaches are considered and recommendations are made
concerning the steps necessary for the successful transition of promising approaches.
15. SUBJECT TERMS
vestibular, balance, equilibrium, concussion, brain injury, head injury
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a. REPORT b. ABSTRACT c. THIS PAGE
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Loraine St. Onge, PhD
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334-255-6906
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Acknowledgments
The authors thank the following people for their help: a) Art Estrada, for frequent assistance with
various aspects of project management, b) Tony Hughes, for assistance with the rotating room
study described herein, c) Casey Harris and John Chiasson, for timely technical support, and d)
Lori StOnge, for extensive assistance with the preparation of this manuscript.
Table of contents
Page
Introduction ......................................................................................................................... 1
Relevant background findings ............................................................................................ 3
Group consideration of three tactile sway cueing approaches ....................................... ....4
Outcome of the initial group evaluation and subsequent developments ……………….....9
Conclusions and Recommendations ................................................................................. 10
References ......................................................................................................................... 12
iii
Introduction
This report summarizes the findings from the U.S. Army Medical Research and Materiel
Command (USARMC) project, “Using tactile cueing systems in traumatic brain injury (TBI)
patient mental and physical rehabilitation.” The objective of this project was to explore three
different systems for providing tactile sway cueing as a compensatory strategy for patients
suffering from disequilibrium due to TBI. Partly based on the first author’s aviation-related
research on the Tactile Situation Awareness System (TSAS) to prevent spatial disorientation,
other investigators (e.g., Wall & Kentala, 2005; Atkins, 2009) have explored the feasibility of
using TSAS-like systems to provide sway feedback to improve standing balance among patients
experiencing disequilibrium (see this Introduction and the next section on Relevant Background
Findings).
Rather than proceeding with a TSAS-based system as the default approach for tactile cueing,
the first author wished to attain greater objectivity by consulting other experts and asking them to
consider a TSAS-based cueing system versus two other available tactile sway cueing systems.
That first group evaluation to identify the advantages and disadvantages of three sway cueing
systems was the purpose of this USAMRC project, the outcomes of which are described in this
report. This report describes a preliminary qualitative evaluation; further and more objective
evaluations are in progress (see Conclusions and Recommendations).
To achieve the stated purpose of group evaluation of multiple possible alternatives to TSASbased sway cueing, meetings were held with experts from the Veterans Administration, U.S.
Army, U.S. Navy, and U.S. Marine Corps as well as researchers involved in the development of
tactile cueing devices. The meetings sought to evaluate the best forms of tactile cueing to
provide balance rehabilitation for brain injured Soldiers. Feedback from military physical
therapy (PT) experts was incorporated into a plan for future efforts in diagnostics and
rehabilitation, as well as Small Business Innovative Research (SBIR) to support the needed
technologies and assist with transition for widespread use. The following report describes the
outcome of these meetings and the best path forward. We start below with a brief description of
the problem of disorientation.
The sensory systems we use for balance, orientation, and ambulation are the somatosensory
(skin, muscle, joint), vestibular, and visual systems. In our day-to-day activities, these three
sensor systems provide concordant, redundant, and veridical information concerning orientation.
As Helmholtz pointed out in the 19th century, spatial awareness is designed such that each sense
can “happily supply each other’s deficiencies” (Helmholtz, in Warren & Warren, 1968).
The situation changed when humans developed devices permitting them to enter the
aerospace environment, where they lost the benefit of these redundant sensory feedback
systems.Unusual graviotinertial forceenvironments are generated during aerospace operations,
where vestibular and somatosensory cues are misleading and redundancy is lost, making spatial
disorientation more likely. To fly safely in the aviation environment, we rely on inertial sensors
to provide the information normally provided by the vestibular and somatosensory systems. The
information from the aircraft orienting sensors is provided visually on an instrument panel and
1
must be attended to and cognitively interpreted. Many mishaps occur when pilots do not attend
to the visual instruments frequently enough and make inappropriate control inputs, causing the
aircraft impacts the ground.
On earth, orientation information is provided to our central nervous system at lower levels of
awareness continuously and in a highly automated fashion. This permits us to carry out the very
difficult tasks of walking and running with minimal cognitive effort. However, when patients
suffer from sensory maladies (e.g., vestibular disease or injury), a similar failure of sensor
redundancy occurs and disorientation is experienced. In fact, the disorientation experienced by
balance patients has more rapid adverse consequences than that suffered by the disoriented
aviator.
In 1993, an ear, nose, and throat specialist, James Atkins, M.D., (a former U.S. Air Force
[USAF] flight surgeon) and a vestibular rehabilitation physiotherapist, Karen Atkins, Ph.D.,
realized the potential earthbound balance applications of my (Angus Rupert) research on spatial
disorientation in flight, so they invited me to present my work to the balance community. My
colleagues and I had developed a novel approach to reduce spatial disorientation (SD) mishaps in
the aerospace community and assist with situation awareness (SA) by providing orientation
information (e.g., aircraft attitude) through the sense of touch (Rupert, Mateczum, & Guedry,
1990; Rupert, Guedry, & Reschke, 1994; Raj, Suri, Braithwaite, & Rupert., 1998; McGrath,
Estrada, Braithwaite, Raj, & Rupert, 2004). Our solution for the loss of aircraft control was to
provide the orientation sensor information continuously through the sense of touch and utilize
the tactile orientation reflexes developed over millions of years to maintain orientation
intuitively, thereby releasing the cognitive demands of the visual system for other tasks. This
system is known as the Tactile Situation Awareness System (TSAS). The TSAS concept was
first presented in Copenhagen at a 1989 NATO AGARD meeting (Rupert, et al., 1990) and first
flown in 1991 (Rupert, et al, 1994). Research by our group and others indicated that tactile
feedback could improve spatial orientation in real and simulated flight (Rupert, 2000; Cardin,
Vexo, & Thalman, 2006; Curry, Estrada, Grandizio, & Erickson, 2008; Brown, 2009).
Drs. James and Karen Atkins hypothesized that our algorithm for providing pitch and roll
stability in aviation platforms could be applied to balance patients using center-of-gravity
information from a balance platform. Determining whether this solution was feasible would
contribute to the field of vestibular rehabilitation (Herdman, 1999) and constitute something akin
to an “acid test” concerning whether TSAS is intuitive and rapidly interpretable, because the
system would be tested not on select groups of healthy aviators who would have 2 to 30 seconds
to react appropriately to prevent spatial disorientation, but on patients with severe balance
problems whose compensatory reactions would have to be implemented within tens of
milliseconds. Some earlier findings suggested that tactile cueing might work – these are
described briefly below.
2
Relevant background findings
Circa 2003, as part of a Naval Air Systems Command (NAVAIR) project, we exposed
subjects to a rotating room to look at adaptation and aftereffects associated with motion and
synthetic environments. While the room rotated slowly (at 24 degrees per second [dg/s] or 4
rotations per minute [rpm]), the subjects made single pitch and roll head movements and walked
from one chair to another chair before resting for 45 seconds. After 10 minutes, subjects began
to adapt to the new environment, showing eye reflexes and coordinated walking movements
appropriate to the new rotating environment. When subjects left the room to be tested on the
balance platform and be compared to their performance prior to becoming adapted on the
rotating room, some subjects reported that head movements felt “unusual” or “funny” and made
them unsteady. The subjects did not demonstrate any pre- to post- performance difference on
regular Neurocom Equitest Sensory Organization Tests (SOTs), but did on a modified version of
the SOT 5, in which subjects close their eyes and move their heads while standing on a platform
that measures their center-of-gravity and provides tilt of the platform in the direction the centerof-gravity is shifting. This test has since been incorporated by the manufacturer of Equitest into
the software and is now used by NASA as an objective test to determine when returning
astronauts are safe to fly (Jain, 2010).
Since we had tactile cueing devices readily available from the TSAS aviation projects, we
performed a small pilot test on five experimenters. We placed tactors on rotating-room-adapted
subjects (front and back of torso) and then provided center-of-gravity information from the
platform to the front or back of the torso to indicate which way they were swaying. The subjects
with tactile cueing could maintain upright posture while subjects without tactile cueing could not.
Two important results were obtained from the initial pilot test: first, tactile cueing could be used
reflexively to improve balance performance in compromised individuals, and second, adaptation
to a rotating environment could be used to create a temporary, rapidly reversible, “acute
vestibular insult”. This pilot test was followed by a series of assessments conducted in
cooperation with Dr. Conrad Wall and his student (at the time), Ms. Patricia Schmidt, and
became the basis for subsequent experiments (Wall & Kentala, 2005; Peterka, Wall, & Kentala,
2006). In place of center-of-gravity information from the platform, Dr. Wall substituted small
inertial sensors developed by Draper Laboratory and mounted these on the torso. In the interim
there has been considerable engineering work to develop sensor and tactor technologies to permit
an ambulatory application of tactile feedback. Tactor configurations are explained briefly below.
The approach used in 1991 to maintain straight and level flight in an aircraft was to employ
a 5 by 8 matrix of tactors around the torso at 45 degree spacing starting at the navel. The
configuration of eight columns was selected to accommodate the conditions of pure pitch (fore
and aft), pure roll (left and right), and combined pitch and roll (four intermediate positions on the
torso). The simpler, reduced configuration of providing combined pitch and roll by using two
tactors (front and back and a left and right) simultaneously did not work well since it required
training and cognitive effort to become proficient. In the initial 1991 flights, the matrix
employed five horizontal rows to provide the extent/magnitude of roll and pitch. When the
object was simply to maintain straight and level flight (i.e., the equivalent of upright balance)
only the bottom row was required which led to the development of a single belt for terrestrial
3
applications. The single belt was used for navigation, location of targets, and balance on the
equitest platform.
The single row TSAS (1 by 8) tactor belt was selected by Karen Atkins for her doctoral
dissertation at the College of Allied Health and Nursing, Nova Southeastern University. Atkins’
dissertation concerned the treatment of patients experiencing balance dysfunction. Her
dissertation research was designed to promote sensorimotor brain reorganization during balance
exercises by providing sensitive real-time sway feedback to the patient via touch. It was hoped
that this approach would exploit brain neuroplasticity by fostering sensory substitution (Bach-yRita, 1987), thus helping the patient return to normal postural coordination.
Although very little was known about the usefulness of tactile cueing for balance
rehabilitation when Atkins started her dissertation, the rationale for the dissertation topic was
strengthened by the fact that tactile cues had been shown to be localizable with certain variations
in the stimulus provided or the age of the user (Cholewiak & Collins, 2003; Cholewiak, Brill, &
Schwab, 2004). Also, tactile cueing had proven beneficial as an assistance device to yield acute
improvement of gait (Dozza, Wall, Peterka, Chiari, & Horak, 2007) and standing balance among
healthy young and old persons (Peterka, Wall, & Kentala, 2006; Verhoeff, Horlings, Janssen,
Bridenbaugh, & Allum, 2009), as well as patients with central or peripheral vestibular pathology
(Wall & Kentala, 2005; Danilov, Tyler, Skinner, Hogle, & Bach-y-Rita, 2007). Hence, Atkins
took the next step to determine if TSAS could improve balance rehabilitation outcomes, even for
those with significant problems such as stroke-related imbalance. Moreover, Atkins sought to
extend the past findings from the scientific study of balance by vestibular researchers to the
clinical study of balance improvement within the context of physical therapy, which is critical to
the clinical transition of tactile cueing. Atkins’ dissertation (Atkins, 2010) found that TSAS was
beneficial for standing balance therapy and recommended further research to determine the full
array of functional abilities which may be improved.
Group consideration of three tactile sway cueing approaches
The government and its partners conducted extensive hardware development and evaluation
efforts prior to the successful test of the 1 by 8 tactor belt by Atkins (2010) for rehabilitation.
Evaluation of the best tactile stimulus candidates occurred at a meeting held at the Institute of
Human and Machine Cognition (IHMC) in Pensacola, FL in 2009. The primary goal of the
IHMC meeting was to further the development of the “sensory substitution” concept as
forwarded by the late Paul Bach-y-Rita. Dr. Bach-y-Rita proposed that the sense of touch could
be “substituted” for the sense of vision with large arrays of stimulators on the torso to provide,
for example, pictures or letters (Bach-y-Rita, 1987). A group of experts met to experience the
capability of the various tactile candidate systems to improve balance among persons suffering
from disequilibrium. The group consisted of Drs. Anil Raj, Fred Guedry, Wally Grant, Jan
Holley, Ian Curthoys, and Angus Rupert. The three technologies evaluated included: 1) the
tactile tongue interface BrainPort (Wicab, Inc., Middleton, WI); 2) the VideoTact array
(ForeThought Development, LLC); 3) an in-house modified version of TSAS. The panel’s
thoughts are summarized below:
4
a. BrainPort
(1) Summary of features
(a) The BrainPort balance device is composed of two components: the intraoral device
(IOD) and the controller. The IOD is made up of an electrotactile array and a MEMS 3-Axis, ±
2 grams, digital output x-y-z accelerometer (Danilov et al., 2007). A flexible cable connects the
IOD to the controller. The electrically-bioisolated accelerometer senses fore-aft and lateral head
position.
(b) Electrotactile stimuli are delivered to the dorsum of the tongue by the 10 by 10
element electrode array. The IOD array and tether are fabricated as a flexible circuit using
industry-standard photolithographic techniques employing a polyimide substrate. One hundred
conductors in the tether are connected to array electrodes, while the remaining six conductors
provide power and communication links to the accelerometer. The 1.5-millimeter (mm) diameter
electrodes are arranged in a square pattern on 2.32-mm centers. The array footprint is 24 by 24
mm. Each electrode isolated with a 127 nanometer (nm) thick layer of gold. The tether (12-mm
wide by 2-mm thick) connects the electrode array and accelerometer to the controller. The
controller contains an embedded computer (ColdFire MCF5249C, 120 megahertz [MHz], 32-bit
microprocessor), stimulation circuits, user controls, and battery power supply. Custom software
operating on the controller converts signals from the accelerometer in the IOD into a dynamic 2
by 2 electrode pattern of electrotactile stimulation. Control buttons allow the user to preset their
own maximum stimulation intensity level.
(c) Head position information derived from the accelerometer is used to position the
tactile stimulus pattern on the tongue display (electrode array). The accelerometer data is
acquired at 50 hertz (Hz) for the purpose of feedback to the user. In the current implementation,
mapping the 12-bit data to the 10 by 10 oral tactile array causes ‘binning’ of the output signal
into 2.8-degree increments both lateral (x-axis) and anterior/posterior (y-axis) to individual tactor
rows or columns, to a maximum range of ±14 degrees in each direction. Consequently, high
frequency small amplitude motion signals typically stay within a bin and are not detected by the
user.
(2) Strengths and limitations
(a) Strengths:
1. The tongue is more sensitive than the torso and has a large portion of the sensory
homunculus devoted to processing.
2. The tongue is located very near the brain (for the most rapid possible response to
sway cues).
5
3. Cueing systems designed for the tongue will necessarily be small and ultimately,
ambulatory.
4. The tongue is both a means of sensing touch cues and a means of actively
controlling assistance technologies (e.g., changing gain or sign of the system for different
applications or user states), whereas the torso is more likely to be exploited for passive cutaneous
sensation, or to require manual intervention for changes to the setting of the system. Hence, a
tongue-based system may be well suited to situations where system settings must be changed
frequently, discretely, or by a user without access to full manual control.
(b) Limitations:
1. Research indicates that factors other than distance from the brain account for the
majority of variance in the literature on human reaction time (Welford, 1980).
2. The horizontal top surface of the tongue maps less intuitively to 3-dimensional
external space and is a less obvious substrate for the representation of wide field flow
information concerning one’s body movement through space.
3. The tongue is required for taste and speech, which means that distraction may
occur from these other activities when one is using the display, which requires the user to hold
his or her tongue still against the device.
4. It is somewhat more difficult to create a confidential assistive device using the
tongue unless the current wires going out of the mouth are engineered out of the system.
Fortunately, the later model of Brainport is wireless, but even so, having a device in the mouth
may feel more uncomfortable, distracting, or obvious to others than supplying the cues to some
other area of the body, thereby limiting patient acceptance. Moreover, due to the tiny size of
discrete stimulation points needed for a tongue array, the stimulus is usually electrotactile in
nature, rather than vibrotactile. While the electrotactile application is safe and may be effective,
it may be more difficult for some users to accept.
5. An important limitation to the Brainport solution are that the multi-center trials
have not worked (Goebel, Sinks, Pyle, Brey, Eggers, & Zapala (2008)
6. Subsequent to the evaluations in Pensacola, the Brainport company appears to
have gone out of business, which severely limits equipment procurement and transition
opportunities.
(c) Caveat: It should be noted that one of the system evaluators (Raj) has had more
experience and involvement with tongue-based solutions than any other solutions described
in this report.
6
b. VideoTact
(1) Summary of features
(a) See ForeThought Development, LLC website at www.4thtdev.com/vidtech.html.
(b) A large array of 768 electrotactile tactors arranged in a 24 by 32 matrix
(c) Relatively high resolution array in thin, flexible, abdominal-mounted, laminated
sheet.
(d) Camera-based. The system is designed to interface with a computer-based imagegrabber board to process information from a video camera.
(2) Strengths and limitations
(a) Strengths:
1. Low power consumption.
2. Ambulatory with small computer supporting the stimulator.
3. Control of many stimulus variables: the pulse width, pulse amplitude (for each
phase), inter-pulse null, and the number of pulses per burst are each independently controlled
variables for each tactor.
(b) Limitations:
1. Camera-based recognition algorithms.
2. With current system, only a single plane array is available to cover the typical
abdomen.
3. The primary difficulty experienced with electrotactile arrays is a result of the
narrow band between the threshold for perceiving the stimulus and the experience of painful
stimuli. Although this feature has been improved by maintaining a uniform contact through the
use of electrode pastes, the paste itself is not readily accepted by the user community.
c. TSAS
(1) Summary of features
(a) Vibrating tactors are arranged around the torso to provide sway information via the
location (sway direction) and rate of vibration (sway magnitude). The computer processor used
7
is 3.6 by 3.8 inches, and weighs about 3 pounds. This apparatus is fixed to the tactor belt
garment, which is held on by Velcro. The belt contains the tactors, a controller, and a battery.
The sites of stimulation, spacing, and number of tactors have been refined in research such as
that carried out by Cholewiak, Brill, & Schwab (2004). Drawing partially from their work, we
employ a single belt of eight tactors surrounding the waist for the current application.
(b) Mortimer, Zets, and Cholewiak (2007) recommend that optimal tactors should have
a frequency response up to 300 Hz, a displacement output that exceeds 24 decibels (dB), and a
rise time of less than 5 milliseconds (ms). They also recommend that when multiple, wearable
tactors are used the tactors should be small and able to generate a highly localized, punctuate
signal. Such performance is possible with Dr. Zet’s C2 linear-actuated tactors to be employed in
this project. The standard Engineering Acoustics, Inc, (EAI) C2 tactor design yields a rugged,
low profile package with nominal center frequency of 250 Hz. The stimulus is a varying pseudo
sinewave in the range of 31 to 300 Hz. The skin contactor is 0.3 inches diameter and is preloaded when the face of the tactor is placed against the skin. The Eval.2.0 tactor controller is an
integrated control module that is capable of operating up to eight C2 tactors. The controller can
be battery operated and is directly addressed via a RS232 serial or USB interface, using standard
software protocols. Optional features include a Bluetooth wireless adaptor and additional onboard memory using a secure digital (SD) memory card. The Eval.2.0 controller is able to
activate single or multiple C2 tactors under software control. Predefined tactile patterns
(“sequences”) can be stored in the on-board memory and activated with a single command.
Multiple boards may be connected together in a master-slave configuration, capable of
controlling up to 64 tactors. EAI’s Eval.2.0 interface/controller is intended as a commercial offthe-shelf solution to a wide variety of tactile applications, and is well-suited for the current
application.
(2) Strengths and limitations
(a) Strengths:
1. The torso is relatively stable and has a large area dedicated to touch sensation
and thus free for the processing of artificial tactile cues that can easily be exploited for a wide
range of applications beyond the simple cueing of sway in the horizontal plane such as would be
possible using a display on top of the user’s tongue (e.g., torso cueing readily can be used to aid
control of descent and ascent during vertical motions).
2. While tongue sensations are primarily used to control tongue movement relative
to the teeth, palate, and lips (for speech or to assist with eating), torso skin sensations are used
for tasks which have more obvious relevance to body-centric orientation, i.e., to spatially map
the location and motion of the body in space (e.g., pressure on the back in different orientations
or during different accelerations) or of objects on the body (e.g., a mosquito).
3. It is feasible to create a confidential assistive device using the torso. A solution
involving vibrotactile stimulation to the torso is likely to be accepted by patients, provided it is
easy to don, comfortable to wear, and not too noisy or distracting.
8
(b) Limitations:
1. The vibrotactile actuators are acoustically louder and use more energy than
electrotactile solutions.
2. The vibrotactile device is larger than electrotactile solutions.
(c) Caveat: As noted earlier in this report, the first author (Rupert) has had more
experience and involvement with TSAS-based solutions than any other solutions
described in this report.
Outcome of the initial group evaluation and subsequent developments
The group of six evaluators (which included the first author) concluded that, of the three
displays evaluated above, the TSAS display was most ready for further study. As a result of the
evaluations, a single row array was developed by the U.S. Navy and supplied to the U.S. Army
Aeromedical Research Laboratory (USAARL) for flight applications (called “TSAS Lite”) and
to the USAF for navigation and triage (Marco Polo program). Units were also loaned to several
universities for evaluation. One loaned unit was a single-row vibrotactile device selected by Dr.
Atkins for her dissertation work on balance rehabilitation following brain injury. This
technology has proven to be beneficial for rehabilitation of balance following certain kinds of
brain injury.
Other efforts are underway to determine the best use of this device. The various academic,
commercial, and military efforts described in this report are yielding important technology
transitions. The prototype rehabilitation technology, developed by Electrical Acoustics
Engineering and partly an offshoot of DoD-funded programs to reduce aviation disorientation
mishaps, is now being improved to serve as a fully functional clinical device ready for field use.
This report concludes by identifying some key transition areas and by listing our
recommendations for the next steps in development.
One application of this device would be to assist military personnel experiencing mild
traumatic brain injury (mTBI) following exposure to improvised explosive devices (Lawson &
Rupert, 2010), the majority of whom show evidence of vestibular pathology (Balaban & Hoffer,
2009; Hoffer, Gottshall, Balaban, & Balough, 2010). The rehabilitation technology described
herein should aid wounded warriors as well as other patients whose balance has been disrupted
by causes not restricted to explosions, such as labyrinthine disorders, diabetes, sports injuries,
traffic injuries, injuries associated with experience as a prisoner of war (Sausen, Clark, Ambrose,
Mitchell, Stiney, & Bower, 2001), or normal sensory degradation associated with aging (Luxon,
in Baloh & Halmagyi, 1996; Baloh & Honrubia, 2001; Tanielan & Jaycox, 2008; Krejcova &
Cerny, 1989; Wikstrom, Naik, Lodha, & Cauraugh, 2009; Bonnet, Carello, & Turvey, 2009).
Improved measures and countermeasures are important for restoring the functional ability of
patients with these problems.
9
Relevant work is being initiated concerning these issues by the authors of this report, EAI,
and Dr. Atkin’s company, BalanceSense. These efforts are supported by U.S. Army-funded
projects, a congressionally-directed project, and SBIR projects. Also, a series of workshops is
being initiated by the Coalition Warfare Program, which will bring together international subject
matter experts to finalize the best practices for clinical implementation of the technology.
Conclusions and Recommendations
This report explored the use of tactile sway cueing as a compensatory strategy for patients
suffering disequilibrium. Sway feedback systems have the potential to aid Soldiers with MTBI
and other patients whose balance has been disrupted by concussions, labyrinthine diseases, or
aging. Several sway biofeedback approaches were evaluated and their strengths and limitations
identified. A TSAS-based system was selected for further study by the first author and five other
system evaluators. The six evaluators were unanimous in their recommendations, but it should be
noted that the first author (Rupert) has had more experience with TSAS-based solutions than any
other solution. Recommendations are made below concerning the necessary steps remaining in
the development and successful transition of this technology:
a. Develop portable balance assessment tool and tactile feedback device based on center-of
gravity information from a posturography platform. Involve the PT community as the
lead for more extensive and more objective comparison and modification of available
approaches, leading to development and refinement of an optimized cueing device.
b. Obtain U.S. Food and Drug Administration (FDA) approval for a predicate device to
deliver to the PT community for vestibular rehabilitation.
c. Develop an SBIR to incorporate audio and visual enhancements to improve the current
state-of-the-art device.
d. Develop a SBIR/Small Business Technology Transfer Research (STTR) to deliver
hardware permitting accurate and dynamic center-of-gravity information in real time.
e. Initiate via Army Research Office (ARO) a Multiple University Research Initiative
(MURI) to begin a multisegmental postural control algorithm incorporating multisensory
feedback loops as prostheses for ambulatory personnel.
f. Develop a device/application which models and simulates acute vestibular injury to
permit rapid evaluation of new devices intended for treatment of mTBI.
As of the present date, the authors are involved in funded efforts addressing items a through
c above and are initiating conversations and proposals geared towards items d through f. We
believe that tactual sway cueing has an important role to play in future military balance testing,
rehabilitation, and assistance following mTBI and are working to promote the transition of this
10
technology to the military and civilian sectors. Since the much larger issue of falls is partially
addressed by this same assessment/rehabilitation technology, the goal is to involve other
agencies, especially the National Institutes of Health, for a coordinated approach to
accomplishing the above goals and recommendations.
11
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