Randomized Clinical Trial of Balance-Based
Torso Weighting for Improving Upright
Mobility in People with Multiple Sclerosis
Neurorehabilitation and
Neural Repair
Volume 23 Number 8
October 2009 784-791
© 2009 The Author(s)
10.1177/1545968309336146
http://nnr.sagepub.com
Gail L. Widener, PhD, PT, Diane D. Allen, PhD, PT, and Cynthia Gibson-Horn, PT
Background. Torso weighting has sometimes been effective for improving upright mobility in people with multiple sclerosis, but parameters for weighting have been inconsistent. Objective. To determine whether balance-based torso weighting (BBTW) has immediate
effects on upright mobility in people with multiple sclerosis. Methods. This was a 2-phase randomized clinical trial. In phase 1, 36 participants were randomly assigned to experimental and control groups. In phase 2, the control group was subsequently randomized into 2
groups with alternate weight-placement. Tests of upright mobility included: timed up and go (TUG), sharpened Romberg, 360-degree
turns, 25-foot walk, and computerized platform posturography. Participants were tested at baseline and again with weights placed according to group membership. In both phases, a physical therapist assessed balance for the BBTW group and then placed weights to decrease
balance loss. In phase 1, the control group had no weights placed. In phase 2, the alternate treatment group received standard weight
placement of 1.5% body weight. Results. People with BBTW showed a significant improvement in the 25-foot walk (P = .01) over those
with no weight, and the TUG (P = .01) over those with standard weight placement. BBTW participants received an average of 0.5 kg,
less than 1.5% of any participant’s body weight. Conclusion. BBTW can have immediate advantages over a nonweighted condition for
gait velocity and over a standardized weighted condition for a functional activity in people with multiple sclerosis (MS) who are ambulatory but have balance and mobility abnormalities.
Keywords: Multiple sclerosis; Physical therapy; Balance; Movement outcomes
I
n a recent sample of 354 middle-aged and older adults with
multiple sclerosis (MS), 93.7% indicated that they had problems with balance and mobility.1 Balance or postural control
requires sensory input (somatosensory, visual, and vestibular),
central integration of sensory information, and selection and
execution of timely motor responses to control head and body
positions for mobility against gravity. Demyelination of various central nervous system connections in people with MS can
affect any of these components of postural control. Cerebellar
ataxia, alone, is a significant cause of balance and gait problems and is present in up to one third of people with MS.2
Weakness, fatigue, tremors, and spasticity, among other factors, were significantly different between 569 fallers and 520
nonfallers in a sample of people with MS. The fallers reported
at least 1 fall in the prior 6 months.3 Physical therapy frequently has a role in helping people compensate for MS-related
impairments and losses in postural control that result in
decreased mobility.4-8
In previous studies and in clinical practice we have seen
improved mobility and postural control with the strategic
placement of small amounts of weight on the torso of people
with MS.9,10 The strategy for this weight placement is called
balance-based torso weighting (BBTW). With BBTW, a clinician places the weights to decrease any balance deviations
observed while a patient stands quietly, reacts to perturbations
at the trunk, walks, and performs transitional movements like
sit to stand. With the weights appropriately placed, patients
seem to have an easier time resisting perturbations and remaining vertical during gait. In a case report,9 results showed that
strategic application of 0.9 kg (2% of the participant’s body
weight) via the BBTW method resulted in increased gait speed,
decreased ataxic movement of the trunk, and less difficulty
turning. A preliminary study of 16 ambulatory participants with
MS showed differences between baseline and BBTW conditions in one or more of the measures of balance and function.10
The purpose of the current study was to test whether the BBTW
system of weight placement affected function when participants were randomized to groups, and whether a standardized
weight placement worked just as well.
Other clinicians have occasionally applied weights to
patients’ trunk, limbs, or assistive devices to help control disordered movement,11-13 but few other researchers have
described the methodical use of weights and their effect on
mobility. Hewer et al14 described the use of 0.2 to 2.0 kg of
weight to control upper extremity intention tremor in people
with cerebellar disease. Morgan15 noted that light weights (1
kg) placed on the lower extremities and (1-2 kg) at the waist
improved gait coordination in people with ataxia (some with
From the Department of Physical Therapy, Samuel Merritt University, Oakland, California (GLW, CGH), and the Graduate Program in Physical Therapy, UCSF/SFSU,
San Francisco, California (DDA). Address correspondence to Diane D. Allen, PhD, PT, 2955 Ramona Street, Palo Alto, CA 94306. E-mail: allendianed@gmail.com.
784
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Widener et al / Balance-Based Torso Weighting in People with Multiple Sclerosis 785 MS) while larger weights increased ataxic movements. Gillen16
added weight as a stabilizing force for an individual with
ataxia from MS to improve upper extremity function. Clopton
et al17 placed 10% of participants’ body weight at the shoulders
or waists to investigate effects on ataxic gait. The BBTW
method incorporates only the amount of weight required to
improve responses of the patients, often less than 2% of body
weight, which is quite different from the protocols described.
The mechanism behind the therapeutic effects of weighting
is unknown. Some have justified it as a means of joint compression to facilitate muscle cocontraction and increased
stability.12,13,17,18 Others see weight placement as a means for
changing the location of the center of mass and thus the
moment of inertia for a body segment, thereby changing the
biomechanics of a movement.13,15 Patients with ataxia have
difficulty controlling body movements. The weighting may
increase control by increasing the afferent input available
regarding changes in biomechanical relationships between
body segments. However, the increase in afferent input may
have more than a biomechanical effect. It may also be a means
of improving awareness of the weighted body segment so that
the person can concentrate on controlling it.19
Each of these proposed mechanisms for the benefit of
weighting in helping to control movement implies that added
weights must be substantial and sufficient to compress joints,
change the perception of the moment of inertia, increase afferent input, or increase awareness of a body segment. On the
other hand, too much weight seems to result in loss of control
for people with strength or endurance losses.15 The dramatic
effects of the very small amount of weight placement in the
BBTW method, described by Gibson-Horn9 imply that even
subtle changes may be enough to improve performance. It may
be that axial weighting affects an individual’s perception of
body position. Studies have shown that humans can perceive a
change in trunk rotation as small as 0.9 degrees20 and lateral
flexion of less than 3 degrees.21 Some individuals may be able
to adjust their control of upright positioning based on a new
concept of self in space. However, participants with BBTW
have said that they forget they have the weights on so increased
awareness of body parts is unlikely as the mechanism for the
effectiveness of weighting.10 The BBTW methods used in this
study, if effective, will support theories of improved mobility
based on subtle changes in sensory input or perception but not
the concept that joint compression or awareness plays a role in
the effectiveness of weighting.
The specific location of weights seems to change the direction of balance loss, which implies that strategic placement of
weights may optimize the effect on mobility. Lucy and Hayes18
reported a specific improvement in lateral postural sway with
standardized placement of 1.36 kg on each shoulder of participants with ataxia from various diagnoses including MS.
Anterior-posterior sway remained unchanged in the majority
of their participants. It would have been interesting to see if
anterior-posterior weight placement had an opposite effect, or
if people with particular problems with increased sway in one
direction could show greater change if weight placement
focused on the direction of postural instability. Clopton et al17
reported that 2 of their 5 participants showed gait improvement when weights were placed at the shoulders, and 2
showed improvement when weights were placed at the waist.
One participant improved with either location of weight placement. Again, a protocol like BBTW that specifically adjusts
weight placement higher or lower according to patient need
may have a more consistent effect on upright mobility.
This 2-phase randomized clinical trial was designed to test
the BBTW method in people with MS and upright mobility
problems. Our aims were to examine the immediate effects of
BBTW on postural control and upright mobility compared
with an unweighted control group and to compare the effect of
BBTW on postural control and upright mobility with the effect
of standard weight placement of 1.5% body weight divided in
2 and equally distributed laterally at the waist.
The null hypotheses were that no postural control or upright
mobility measures would show a difference with weighting, and
that no differences in postural control or upright mobility would
be noted between people with weight placed according to the
BBTW method compared to those with no weight or to those
with standard weight placement (SWP). Our alternative hypothesis was that BBTW would prove beneficial over the unweighted
condition and that it would differ from the SWP condition in
improving performance on the dependent variables.
Methods
Participants were recruited through newsletter ads sent by a
chapter of the National Multiple Sclerosis Society. The following
inclusion criteria for acceptance into this study were: (1) able to
walk 30 feet, (2) difficulty with walking, and (3) afraid of falling. Exclusion criteria were as follows: (1) unwilling to have
balance challenged by a researcher, and (2) timed up and go
(TUG)22 results of less than 8 seconds. The cut-off for the TUG
was chosen to exclude people who had minor difficulty with
walking and thus limit a possible ceiling effect. Figure 1 depicts
the group assignment process. Randomization was stratified
based on performance on the TUG. People who performed the
TUG in 8 to 12 seconds were considered high functioning and
people who performed the TUG in more than 12 seconds were
considered low functioning. Once identified as high or low
functioning, participants drew an opaque envelope from the
high or low functioning pool of envelopes containing the information regarding group assignment. The content of envelopes
was revealed to neither the participants nor the tester. All participants signed informed consent as directed by the Institutional
Review Board of Samuel Merritt University. All participants
answered demographic questions regarding type of MS, time
since diagnosis, number of falls in the past 6 months, and experience with MS-related fatigue. A fall was defined as losing
balance and unexpectedly landing on the floor. All participants
were also measured for strength,23 range of motion (ROM),
and muscle tone24 for flexion and extension at the knees and
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786 Neurorehabilitation and Neural Repair
Figure 1
Research Design With Sequence for Participant Recruitment and Assignment
100
Contacted us
56
Ineligible or
Could not commit
44
Enrolled
3 No shows
3 TUG scores < 8 sec.
38
Subjects
Phase I
Randomized
1 had unrelated
emotional breakdown
19
Control
Phase II
1 TUG score < 8
sec. at BL3
1 unable to follow
directions
19
BBTW
Randomized
10
SWP
8
BBTW
2 TUG scores < 8
sec. at BL3
Abbreviations: TUG, timed up and go; BBTW, balance-based torso weighting; SWP, standardized weight placement; BL3, score at baseline for phase 2.
dorsiflexion and plantarflexion at the ankles to ascertain group
equivalency in these basic measures.
The dependent variables included the following: the TUG22;
the sharpened Romberg25 with time summed across 4 trials in
which participants held the position for a maximum of 30
seconds each with right foot then left foot behind, eyes open
(SREO) and eyes closed (SREC); the timed 360-degree turn
summed across turns to the left and to the right; the 25-foot
walk; and average body sway (in centimeters per second) during 10 seconds of standing with eyes open and then eyes
closed for computerized platform posturography (CPP). The
TUG, sharpened Romberg, 25-foot walk, and CPP were chosen because they were variables used in preliminary testing of
the BBTW in people with MS.10 The 360-degree turn was
chosen because turning had shown change in a case report
with BBTW methods.9 The turn was performed as directed for
the turning item in the Berg Balance Scale (BBS),26 but scored
in the seconds it took to complete a turn, once to the left and
once to the right. All data were collected in the same laboratory space. CPP was performed using a Basic Balance Master
(NeuroCom International, Clackamas, OR). The researcher
(GLW) administering all tests was blinded to test condition.
Body weighting for the BBTW condition followed the procedure established by Gibson-Horn.9 Assessment of balance
included observation of relative amount and direction of sway
during Romberg testing with eyes open and eyes closed. One
researcher (CGH) perturbed (and guarded) the participant with
anterior, posterior, and lateral nudges to the shoulders and
pelvis to identify response latency, amount, and direction of
balance loss. Balance loss was defined as tilt or lean of the
trunk requiring opposing parachute reaction, stepping response,
or manual contact by the researcher to regain center of mass
over the base of support. The researcher applied rotational
force through the shoulders and or pelvis to determine asymmetry in resistance. Small weights were applied to the torso on
a specially constructed vest-like garment that allowed Velcro
application of weights to front, back, or sides of the torso
between the shoulders and waist. The first application of
weights was in a direction to counter the direction of balance
loss and asymmetry of resistance. Balance was reassessed with
the weights in place to determine if greater stability or
decreased response latency was demonstrated. Weights were
adjusted until stability improved with reassessment. The balance assessment took between 10 and 30 minutes (usually less
than 20 minutes) depending on the number of balance-related
errors found. The garment was removed for rest periods, and
redonned for BBTW testing on the dependent variables.
Body weighting for the standard weight placement was
predetermined at 1.5% of the participant’s body weight and
placed at the bottom of the vest, laterally, with half of the
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Widener et al / Balance-Based Torso Weighting in People with Multiple Sclerosis 787 weight on either side of the waist. The garment was removed
for rest periods, and redonned for SWP testing on the dependent variables.
Procedure
For phase 1, both groups were tested for a baseline (BL1)
on all dependent variables. The experimental group had a
15-minute rest and then underwent the BBTW assessment to
determine weight placement on the garment. After another
30-minute rest (in case the BBTW procedure was fatiguing),
the experimental group was retested on all dependent variables. The control group also had a 30-minute rest between the
baseline (BL1) and second testing (BL2). Because some people having BBTW may have carry-over effects, phase 2 only
examined participants from the first control group. For phase
2, participants from the control group from phase 1 returned
on another day and were tested on the dependent variables for
another baseline (BL3). Phase 2 participants were then randomly assigned to 1 of 2 alternate condition groups. Only
participants in the BBTW group received balance assessment.
After 30 minutes of rest, one group received BBTW, and the
other group received SWP. Participants were then tested again
on all dependent variables.
Blinding of the tester in both phases for test condition on all
dependent variables was accomplished by having participants
don an oversized black t-shirt to hide the presence or absence
of the BBTW or SWP garment. Participants in phase 2 were
unaware of the test condition, whether BBTW or SWP.
Data analyses were performed with SPSS version 15.0
(SPSS Inc, Chicago, IL). Analyses to determine the significance of the differences between groups at baseline (with α =
0.05) included the following:
1. t tests for differences in mean age or years with the
diagnosis of MS;
2. the Mann-Whitney U test for differences in the median
Expanded Disability Status Scale27 (EDSS) score; and
3. χ2 tests for differences in frequency of people claiming
falls or fatigue, or between numbers of females, numbers
of people with different types of MS, numbers of people
designated as high functioning, and numbers of people
with strength, range of motion, and tone impairments.
The data from the dependent variables were expected to
have an abnormal distribution because of the sample size and
expected movement dysfunction, so data analyses were performed with nonparametric statistics. The Wilcoxon signed
ranks test was used to test the paired differences between baseline and second testing for each group in each phase. The
Mann-Whitney U test was used to test differences in the average change in performance between groups in each phase.
The family-wise α was set at 0.10 for each group of tests.
Bonferroni’s correction thus resulted in α = 0.02 for each of the
dependent variables in each group. The alpha was set liberally
because advocating a potentially ineffective but low risk treatment (a type 1 error) is less of a problem to the clinical community than missing a potentially useful treatment when few
treatments have documented effectiveness in this population. All
paired differences and the group differences between the BBTW
and control groups in phase 1 were assessed using 1-tailed tests
because the intervention was expected to make a positive change
in these dependent variables. For phase 2, group differences were
assessed using 2-tailed tests because BBTW and SWP were alternative interventions and the direction of the difference was not
proposed.
Results
Groups were similar with respect to age, years with the
diagnosis of MS, EDSS scores, number of participants claiming one or more falls in the past 6 months, number claiming
MS-related fatigue, and gender (Table 1). Chi-square tests
revealed no significant difference (P > .05) between groups in
numbers of participants with the different types of MS (secondary progressive, primary progressive, or relapsing-remitting),
impairment of knee extension or ankle dorsiflexion ROM, or
at least mild hypertonicity in one of the knee or ankle directions of movement (Table 2). The number of people designated
as high functioning tended to be higher in the experimental
group than in the control group in phase 1 (P < .06), but the
number of people who had less than 4 on a manual muscle test
of any knee or ankle muscle group also tended to be higher in
the experimental group (P = .05). The average weight applied
for the BBTW condition was 0.5 kg. The average weight
applied for the SWP condition was 1 kg.
Test-retest reliability estimates were calculated from the
control group data from BL1 to BL2 (both performed on the
same day). The TUG and 25-foot walk were single scores, so
the intraclass correlation coefficients (ICCs) were performed
as model 3, type 1. The ICCs were 0.98 and 0.96 for the TUG
and the 25-foot walk, respectively. The other variables were
combined scores across trials (eg, right, left, eyes open or
closed), so the ICCs were performed as model 3, type k. The
sharpened Romberg ICC was 0.73, the 360-degree turn was
0.96, and the CPP was 0.80. There were no statistically significant differences between day 1 and day 2 in mean baseline
performances. ICCs ranged from 0.86 to 0.97 for the 5 variables when comparing BL2 and BL3.
In phase 1 (Table 3), participants with the BBTW showed
significant improvement over baseline in the TUG (P < .001),
25-foot walk (P < .001), sharpened Romberg (p < .02), and the
360-degree turns (P < .004). Participants in the control group
showed no significant difference between BL1 and BL2 on any
variable. The 25-foot walk revealed a statistical difference in
change scores between the experimental and control groups (P =
.01) with an average 8.5% improvement for the BBTW group
versus no improvement for the control group (Figure 2).
In phase 2, examination of baseline scores (BL3) revealed
3 additional participants who had TUG test scores of less than
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788 Neurorehabilitation and Neural Repair
Table 1
Participant Characteristics for Randomly Assigned Groups
Phase 1
Control (n = 18)
Age in years, mean (SD)
Years with diagnosis, mean (SD)
EDSS, median (range)
Number (%) claiming falls in past 6 months
Number (%) claiming MS-related fatigue
Number (%) female
Phase 2
BBTW (n = 18)
P Value
SWP (n = 9)
BBTW (n = 6)
P Value
55.7 (7.5)
13.2 (10.1)
4.5 (2-5)
14 (77.8)
16 (88.9)
16 (88.9)
.40
.96
.41
.66
.23
.23
53.2 (10.9)
12.0 (7.5)
4.5 (2-5)
6 (60)
6 (60)
7 (70)
53.3 (8.8)
15.0 (16.0)
5.0 (3-5)
8 (100)
6 (75)
5 (62.5)
.99
.61
.41
.09
.64
1.00
53.2 (9.7)
13.3 (11.7)
5.0 (2-5)
16 (88.9)
12 (66.7)
12 (66.7)
Abbreviations: BBTW, balance-based torso weighting; SWP, standardized weight placement; EDSS, expanded disability status scale.
Table 2
Number with Type of Multiple Sclerosis or Specified
Impairments for Randomly Assigned Groups
Phase 1
Phase 2
Control BBTW (n = 18) (n = 18)
SWP BBTW
(n = 9) (n = 6)
Secondary progressive MS
Primary progressive MS
Relapsing remitting MS
Unknown type of MS
Number high functioning: 8-12 seconds on TUG
Number with <4/5 strength
for any knee flexion or
extension or ankle
dorsiflexion muscle group
Number with knee extension less than full range
Number with ankle dorsiflexion less than neutral
Number with at least mild
hypertonicity at knee or ankle
2
2
10
4
9
4
4
10
0
13
1
1
5
3
3
1
1
5
1
3
10
13
4
5
8
8
5
2
7
8
4
3
17
17
9
5
Abbreviations: MS, multiple sclerosis; BBTW, balance-based torso weighting; SWP, standardized weight placement; TUG, timed up and go.
8 seconds. Elimination of these participants in our analyses
(consistent with initial exclusion criteria) resulted in 9 participants in the SWP group and 6 participants in the BBTW group.
Participants with BBTW improved over BL3 in the TUG (P =
.01). Participants with SWP improved over BL3 in the 25-foot
walk (P = .004). The TUG test revealed a statistical difference
in change scores between the 2 groups (P = .01) with an average 9% improvement for the BBTW group versus 1.5%
improvement for the SWP group (Figure 3).
Discussion
The null hypotheses could be rejected. The BBTW groups
showed changes in the weighted conditions and showed
greater change than the unweighted control and SWP groups
in a measure of mobility. The lack of difference between
groups across more variables in phase 1 may reflect the relatively high standard deviation in the performance of unweighted
control participants at baseline and second testing in the TUG,
turns, and CPP (see Table 3); however, the mean across these
control participants showed no significant improvement with
second testing on any variable. When these same control participants were provided with alternative weight placements in
phase 2, the improvement in mobility variables by both the
SWP and BBTW groups indicate that weighting can be effective even when not placed in a patient-specific manner. The
SWP group did not show better change in performance, however, on any variable compared to the BBTW group. The
advantage for the BBTW group may have been both the
patient-specific location of the weight and the relatively
smaller amount of weight perhaps resulting in less fatigue, a
common problem for people with MS.
In this study, sharpened Romberg performance proved to be
highly variable, with a test-retest ICC of 0.73 in our control
group. In reliability testing of participants with MS who were
unable to hold a single-leg stance, Fry and Pfalzer28 found that
tandem stance had an ICC of 0.63, with a confidence interval
that crossed zero, indicating even higher variability in this test.
In contrast, Frzovic et al29 reported Spearman rho values of
0.86 and 0.93 for same day test-retest reliability of right and
left legged tandem stance respectively in people with MS.
Compounding the high variability on this test, many participants in our study could not perform the sharpened Romberg
with eyes closed. The sharpened Romberg was included
because it showed change with the BBTW in a previous study,
but the previous sample included people with TUG scores
below 8 seconds and thus higher functioning.10 Future testing
of ambulatory people with MS and lower function might
eliminate the sharpened Romberg testing, at least in the eyes
closed condition and possibly also in the eyes open condition.
In contrast, the average CPP tests showed minimal response to
weighted conditions in this study. One reason for this lack
might be that the average CPP for the experimental group in
phase 1 was 0.5 cm/second, which is the cut-off designated by
the manufacturer for “normal sway.” The other groups also
had averages close to this number. The lack of change might
be evidence of a ceiling effect.
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Widener et al / Balance-Based Torso Weighting in People with Multiple Sclerosis 789 Table 3
Mean (Standard Deviation) Value on Dependent Variables for Control and Experimental Groups in Phase 1
and Standard Weight Placement and Balance-Based Torso Weighting Groups in Phase 2
Phase 1
Control (n = 18)
TUG (seconds)
25-foot walk (seconds)
Sharpened Romberg (seconds held)
360-degree turn (seconds)
CPP (cm/second)
Phase 2
Experimental (n = 18)
SWP (n = 9)
BBTW (n = 6)
BL1
BL2
BL1
BBTW1
BL3
SWP
12.4 (3.6)
7.4 (2.2)
14.4 (21.2)
10.1 (4.3)
0.8 (0.4)
12.1 (3.6)
7.4 (2.2)
13.8 (18.8)
9.5 (4.1)
0.7 (0.3)
11.0 (2.7)
7.0 (2.0)
26.7 (26.6)
7.8 (2.8)
0.5 (0.2)
10.4a (2.4)
6.4a,b (1.6)
33.2a (28.0)
6.8a (2.4)
0.5 (0.2)
13.0 (3.8)
7.8 (1.8)
15.7 (26.2)
9.5 (4.0)
0.7 (0.3)
12.8 (4.0)
7.2a (1.8)
16.6 (26.8)
9.2 (4.4)
0.6 (0.2)
BL3
13.6 (3.4)
7.9 (2.3)
17.6 (26.3)
11.4 (5.4)
0.8 (0.3)
BBTW2
12.4a,b (3.0)
7.7 (2.0)
18.4 (21.3)
10.6 (5.7)
0.8 (0.4)
Abbreviations: BL1, baseline of Phase 1; BL2, second testing of control group in Phase 1; BL3, baseline of Phase 2; BBTW1, experimental group with balancebased torso weighting applied, Phase 1; BBTW2, group with balance-based torso weighting applied, Phase 2; SWP, group with standard weight placement applied,
Phase 2; TUG, timed up and go; CPP, computerized platform posturography.
a
Testing in weighted condition showed a significant improvement over baseline.
b
Testing in BBTW condition showed significantly different improvement over alternative condition in that phase of testing.
Figure 2
Phase 1, the 25-Foot Walk: Results of 18 Control Participants (Designated 1-18) at Baseline (BL1) and
Time 2 (BL2), and 18 Experimental Participants (Designated 19-36) at Baseline and With the
BBTW Revealed a Statistical Difference in Change Scores Between the Groups (P < .01)
14
12
Seconds
10
8
6
4
2
0
1
4
7
10
13
16
19
22
25
28
31
34
Subjects
BL1
BL2
BBTW
Abbreviation: BBTW, balance-based torso weighting.
The 25-foot walk is one of the standard timed walk tests
used in research for people with MS. The results of our study
suggest that weighting may have a positive effect on gait
velocity. We observed an 8.5% improvement in the experimental group. The TUG test, while not a standard MS test, is
used by many rehabilitation specialists because it contains sit
to stand transfers, gait, and turns, many of the daily activities
a person with MS might encounter. We found a significant difference between the alternate weighting groups in this functional variable, with a 9% improvement for the BBTW group.
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790 Neurorehabilitation and Neural Repair
Figure 3
Phase 2, TUG: Results of 9 Control Participants (Designated 1-9) at Baseline (BL3) and With SWP
and 6 Experimental Participants (Designated 10-15) at Baseline and With BBTW Revealed a
Statistical Difference in Change Scores Between the Groups in Favor of BBTW (P = .01)
25
20
Seconds
15
10
5
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
Subjects
BL3
SWP
BBTW
Abbreviations: TUG, timed up and go; SWP, standardized weight placement; BBTW, balance-based torso weighting.
The improvements in upright mobility scores, as an immediate
effect of BBTW, compare favorably with improvements noted
in other reports of balance interventions in MS. For example,
Wiles et al6 reported an 8% improvement in walking speed
after 2 sessions of physiotherapy a week for 8 weeks. It would
be interesting to see if use of weighting along with active
intervention would increase this effect in a shorter time.
Few studies have used other sensory input as a method of
modifying postural control and function in people with MS.
Schulfried et al30 compared a single bout of whole body vibration (WBV) with a placebo of transcutaneous electrical nerve
stimulation (TENS) in people with MS and walking difficulties. They found no significant differences between groups
immediately after WBV in functional reach, TUG, or sensory
organization testing. The 0.6 second improvement in TUG
scores for the 6 people in the WBV group, although it did not
reach statistical significance, compares with the 0.6 second
improvement in TUG scores with BBTW in phase 1 of the
current study but is less than the 0.9 second improvement in
phase 2. Neither study included other rehabilitation techniques
along with the sensory input.
This study design controlled for some learning effects possible with repeated testing, a possible source of improvement.
Participants in the phase 1 control group performed the activities
required by the dependent variables at baseline and second testing,
and again for a second day baseline and intervention testing with
weight placement according to group designation. No significant
differences were noted in any variables between the baseline and
second testing in phase 1, or between baseline for phase 1 and
baseline for phase 2. Learning did not have a significant effect on
performance over the 4 repetitions of testing in this study.
Limitations
This was a relatively small pilot study in a sample of participants with MS and acknowledged balance deficits. The results
cannot be generalized to the function of all people with MS. On
the other hand, it is possible that people with balance and mobility abnormalities resulting from pathologies other than MS may
also benefit from this technique. Only one of the variables in
each phase of the study showed a significant difference between
groups. The significant improvements between BL1 and BBTW
in phase 1 and trends in some variables across groups also
seemed to favor BBTW, however. Further research might investigate the characteristics of people with MS or other pathologies
who benefit most from weighting with the BBTW system when
Downloaded from nnr.sagepub.com at UNIV OF DELAWARE LIB on January 8, 2015
Widener et al / Balance-Based Torso Weighting in People with Multiple Sclerosis 791 assessed across a more focused set of variables. Future studies
will need to assess the repeatability of the balance assessment
for weight placement; this was not needed in this study since
only 1 person performed all balance assessments.
Only immediate effects were examined in this study. Longterm effects of weighting or any carry-over after weighting is
removed were not evaluated. Further research might investigate carry-over effects, or determine whether weighting is an
orthosis that improves function only while applied or an intervention that changes function because people can practice or
exercise differently during the application period. Such differentiation could enhance our understanding of the mechanism behind any changes in mobility noted with weighting.
Assessment for BBTW could take up to 30 minutes and
seemed to be fatiguing for participants, possibly affecting performance even after a 30-minute total rest time. In addition,
the activities and perturbation required during balance assessment could have had positive effects. Future research might
need to incorporate the balance assessment portion of the protocol for all groups, whether or not participants are assigned to
get weight application.
Although group assignment was randomized and no differences were noted in EDSS scores, strength, ROM, or tone
between control and BBTW groups at baseline, the BBTW
group in phase 1 may have had higher functioning. A total of
13 out of 18 participants in the BBTW group performed the
TUG in less than 12 seconds, compared to 9 out of 18 in the
control group, meaning that perhaps an over-all ceiling effect
limited the ability of participants in the BBTW group to show
change compared to the control group.
Conclusion
Weighting the torso can produce an immediate change in
upright mobility, with some advantage noted by participants
who had torso weighting applied with the BBTW system.
People with MS who are ambulatory but have balance or
mobility abnormalities may benefit from this intervention.
Acknowledgment
This study was funded by the National Multiple Sclerosis
Society, grant PP1052.
References
1.Peterson EW, Cho CC, von Koch L, et al. Injurious falls among middle
aged and older adults with multiple sclerosis. Arch Phys Med Rehabil.
2008;89:1031-1037.
2.Weinshenker BG, Issa M, Baskerville J. Long-term and short-term outcome of multiple sclerosis: A 3-year follow-up study. Arch Neurol.
1996;53:353-358.
3.Finlayson ML, Peterson EW, Cho CC. Risk factors for falling among
people aged 45 to 90 years with multiple sclerosis. Arch Phys Med
Rehabil. 2006;87:1274-1279.
4.Lord SE, Wade DT, Halligan PW. A comparison of two physiotherapy
treatment approaches to improve walking in multiple sclerosis: a pilot
randomized controlled study. Clin Rehabil. 1998;12:477-486.
5.Rodgers MM, Mulcare JA, King DL, et al. Gait characteristics of individuals with multiple sclerosis before and after a 6-month aerobic training
program. J Rehabil Res Dev. 1999;36:183-188.
6.Wiles CM, Newcombe RG, Fuller KJ, et al. Controlled randomised crossover trial of the effects of phsiotherapy on mobility in chronic multiple
sclerosis. J Neurol Neurosurg Psychiatry. 2001;70:174-179.
7.Gutierrez GM, Chow JW, Tillman MD, et al. Resistance training improves
gait kinematics in persons with multiple sclerosis. Arch Phys Med Rehabil.
2005;86:1824-1829.
8.Smedal T, Lygren H, Kjell-Morten M, et al. Balance and gait improved in
patients with ms after physiotherapy based on the Bobath concept.
Physiother Res Int. 2006;11:104-116.
9.Gibson-Horn C. Balance-based torso-weighting in a patient with ataxia and
multiple sclerosis: A case report. J Neurol Phys Ther. 2008;32:139-146.
10.Widener GL, Allen DD, Gibson-Horn C. Balance-based torso weighting
may enhance balance in persons with multiple sclerosis: Preliminary evidence. Arch Phys Med Rehabil. 2009;90:602-609.
11.O’Sullivan SB. Multiple sclerosis. In: O’Sullivan SB, Schmitz TJ, eds.
Physical Rehabilitation. 5th ed. Philadelphia, PA: F. A. Davis Company;
2007:777-818.
12.Stockmeyer SA. An interpretation of the approach of rood to the treatment
of neuromuscular dysfunction. Am J Phys Med. 1967;46:900-956.
13.Goff B. The application of recent advances in neurophysiology to miss
rood’s concept of neuromuscular facilitation. Physiother. 1972;58:409-415.
14.Hewer RL, Cooper R, Morgan MH. An investigation into the value of
treating intention tremor by weighting the affected limb. Brain.
1972;95:570-590.
15.Morgan MH. Ataxia and weights. Physiother. 1975;61:332-334.
16.Gillen G. Improving activities of daily living performance in an adult with
ataxia. Am J Occup Ther. 2000;54:89-96.
17.Clopton N, Schultz D, Boren C, et al. Effects of axial loading on gait for
subjects with cerebellar ataxia: preliminary findings. Neurol Report.
2003;27:15-21.
18.Lucy SD, Hayes KC. Postural sway profiles: normal subjects and subjects
with cerebellar ataxia. Physiother Can. 1985;37:140-148.
19.Holmes G. The cerebellum of man. Brain. 1939;62:1-30.
20.Taylor JL, McCloskey DI. Proprioceptive sensation in rotation of the
trunk. Exp Brain Res. 1990;81:413-416.
21.Jakobs T, Miller JA, Schultz AB. Trunk position sense in the frontal plane.
Exp Neurol. 1985;90:129-138.
22.Podsiadlo D, Richardson S. The timed “up & go”: a test of basic functional
mobility for frail elderly persons. J Am Geriatr Soc. 1991;39:142-148.
23.Kendall FP, McCreary EK, Provance PG. Muscles: Testing and Function.
4th ed. Baltimore, MD: Williams & Wilkins; 1993.
24.Bohannon R, Smith M. Interrater reliability of a modified Ashworth scale
of muscle spasticity. Phys Ther. 1987;67:206-208.
25.Lanska DJ, Goetz CG. Romberg’s sign: development, adoption, and adaptation in the 19th century. Neurol. 2000;55:1201-1206.
26.Berg K, Wood-Dauphinee S, Williams JI. Measuring balance in the
elderly: preliminary development of an instrument. Physiother Can.
1989;41:304.
27.Kurtzke J. Rating neurological impairment in multiple sclerosis: an
expanded disability status scale (edss). Neurol. 1983:1444-1452.
28.Fry DK, Pfalzer LA. Reliability of four functional tests and rating of perceived exertion in persons with multiple sclerosis. Physiother Can.
2006;58:212-220.
29.Frzovic D, Morris ME, Vowels L. Clinical tests of standing balance: performance of persons with multiple sclerosis. Arch Phys Med Rehabil.
2000;81:215-221.
30.Schulfried O, Mittermaier C, Jovanovic T, et al. Effects of whole-body
vibration in patients with multiple sclerosis: a pilot study. Clin Rehabil.
2005;19:834-842.
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