Clinical Study of a Novel, Body-weight Supported, Balance-perturbation Module During the Rehabilitation of Gait and Balance Impairments Secondary to Stroke: A Multisite Randomized Control Trial
Phase: NA
Conditions: Stroke, Stroke, Acute, Balance; Distorted, Balance; Impairment, Gait, Unsteady
Sponsor: Gaylord Hospital, Inc

NCT05110300 - 1 
 
 
 
 
 
 
 
 
 
 
 
 
 
Official Title: Body-Weight Supported Balance-Perturbations for Post-Stroke Gait and Balance Training 
Rehabilitation: A Multisite Randomized Controlled Trial 
Clinical Trial Number: NCT05110300 
November 6, 2024 
STUDY PROTOCOL AND STATISTICAL ANALYSIS PLAN 
 
 

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1. Methods 
1.1. 
Study design 
This will be a multisite randomized active-comparator controlled clinical trial. Due to the nature of 
the intervention, subjects and investigators will not be able to be masked to the intervention. The 
assessor will not be able to be masked to group assignments, as the presence or absence of 
certain variables in the dataset, namely the perturbation level, will immediately reveal group 
assignment. 
 
Sample Size Estimation and Study Timeline: Using the pilot data, a Cohen’s d effect size of 0.39 
was calculated and a two-tailed power analysis (α=0.05) was conducted. For the observed effect 
size, an estimated sample size of 214 participants would achieve 80% power. Using this estimate, 
and the estimates of the participating sites of the number of potential subjects that could be 
recruited, enrollment is expected to last 12-18 months (Table 1). 
 
Table 1. General Timeline 
Year 1 
Month 
1 
2 
3 
4 
5 
6 
7 
8 
9 
10 
11 
12 
Clinical Trial Registration1 
X 
 
 
 
 
 
 
 
 
 
 
 
Purchasing2 
X 
 
 
 
 
 
 
 
 
 
 
 
Staff Training/Check-in 
X 
 
 
X 
 
 
 
 
X 
 
 
 
Steering Committee meeting 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
Enrollment Target3 
 
12 
12 
12 
12 
12 
12 
12 
12 
12 
12 
12 
Completion Target3 
 
 
12 
12 
12 
12 
12 
12 
12 
12 
12 
12 
Interim data analysis (25% 
and 50% recruitment) 
 
 
 
 
 
 
X 
 
 
 
X 
 
Year 2 
Month 
13 
14 
15 
16 
17 
18 
19 
20 
21 
22 
23 
24 
Staff Training/Check-in 
X 
 
 
 
 
 
 
 
 
 
 
 
Steering Committee meeting 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
Enrollment Target3 
12 
12 
12 
12 
12 
12 
12 
 
 
 
 
 
Completion Target3 
12 
12 
12 
12 
12 
12 
12 
12 
 
 
 
 
Data analysis 
 
 
 
 
 
 
 
 
X 
X 
 
 
Manuscript preparation; 
Poster abstract submission 
 
 
 
 
 
 
 
 
 
X 
X 
X 
Clinical Trial Registration: 
Data updates1 
 
 
 
 
 
 
 
 
 
 
X 
X 
1This study will be registered and maintained at clinicaltrials.gov; Registration will be completed prior to 
recruiting the first subject. 
2If grant funding is able to be attained, purchasing outlined in the grant will be completed in month 1 of the 
award period. 
3Enrollment and completion targets are estimates based on an 18 month enrollment period. For a 12 month 
enrollment period, the enrollment and completion targets would be 18 participants per month, with the 
completion target ending in month 13.  
 
Participants, Settings, and Inclusion/Exclusion Criteria: To participate in this study, participants 
must be recruited at one of the three participating rehabilitation centers: Gaylord Specialty 
Healthcare (Wallingford, CT), MedStar National Rehabilitation Hospital (Washington, DC), or 
Spaulding Rehabilitation Hospital Cape Cod (Sandwich, MA). 
 
To be eligible for study participation, subjects must meet the following Inclusion Criteria: 
• 
Admitted to one of the listed study locations for inpatient rehabilitation following either 

NCT05110300 - 3 
 
ischemic or hemorrhagic stroke and medically stable for the therapy program. 
• 
Be 18 years of age or older. 
• 
Discharge date of 10 days or longer at study consent 
• 
Have at least a moderate fall risk or better, shown by an admission BBS score of 21/56 
or greater. 
o Patients that score below 21 or are non-ambulatory will not be considered for this 
study.  
o Patients that are emergently re-admitted to acute care and subsequently re-
admitted to the stroke rehabilitation program will be reassessed for 
appropriateness of continuation in the study on a case by case basis.  
o Patients that progress to a BBS score of 21 or greater during their stay, and have 
a set discharge date of 10 days or longer, can be approached for study 
recruitment.  
• 
Appropriate cognition  
o Able to read and understand the consent, in English or a language available by 
translator services, based on the judgment of the clinical team, either by using 
outcomes measures, i.e. SLUMS ≥ 20, or through clinical evaluations and team 
discussion. Eligibility will ultimately be decided by the treating physician and/or in 
combination with the participant’s clinical team. 
• 
Ability to tolerate and actively participate in at least 2 and up to 6 study related BWSS 
therapy sessions. 
o Study related therapy sessions will last a minimum of 15 minutes, up to 30 
minutes in the BWSSs.  
 
Those who present with one or more of the following Exclusion Criteria will not be eligible for study 
participation:  
• 
Cognitive deficits that would disrupt the ability to provide informed consent as described above 
• 
Active enteric infection control precautions 
o Subjects would be eligible once precautions are lifted 
• 
Ongoing orthostasis 
• 
Uncontrolled hyper/hypotension  
• 
Active seizures  
• 
Spinal stabilization with the use of Halos 
• 
Unstable skin structures (i.e. skin grafts) 
• 
Chest tubes 
• 
Unstable rib or lower extremity fractures 
• 
Severe osteoporosis  
• 
Subjects where pressure around the abdomen, thighs, groin, or shoulders is contraindicated  
• 
New limb amputations 
• 
Vestibular disorders that may impact balance 
• 
Premorbid conditions that may impact balance 
• 
Patients requiring more than 50% high flow oxygen as consistent with inpatient therapy 
guidelines 
• 
Subjects who weigh more than 450 pounds, per the structural limitations of the ZeroG system 
• 
Anyone belonging to a vulnerable population as described below, including subjects under the 
age of 18 and who are or might be pregnant 
 
Equipment and Instruments: Several pieces of equipment and outcome instruments will be 
needed for this study. The ceiling-track mounted, FDA listed, ZeroG body weight support system 

NCT05110300 - 4 
 
BWSS (Aretech LLC, Ashburn, VA) and the Training Responses in Postural Rehabilitation (TRiP) 
balance perturbation module (Aretech LLC, Ashburn, VA) will be the primary pieces of equipment 
required to complete this study. All study locations already have the ZeroG BWSS and TRiP 
module installed. 
In addition to the equipment, several outcome measurements will be collected throughout 
the study duration. Balance specific measurements that will be collected include the BBS, an 
objective balance measure, and the Activities Specific Balance (ABC) scale, a subjective patient 
reported measure. When appropriate for the patient, an admission BBS is collected within 72 
hours of admission at all study locations by the patient’s primary therapist. This admission 
evaluation will be used to initially identify potential subjects with an admitting BBS of 21 or greater; 
this will be used as the pre-intervention assessment (pre-assessment) during data analysis. When 
patients are discharged, a follow-up BBS is typically collected at all study locations. However, 
discharge may not always occur in a timely fashion after the conclusion of the study. To address 
this, a post-intervention assessment (post-assessment) will be collected within 48 hours of the 
last study session if not already collected by the participant’s primary therapist during that time. 
The patient reported ABC scale will be collected during the informed consent process and 
immediately following the last study session.  
To evaluate gait, the objective self selected 10 Meter Walk Test (10MWT) assessment will 
be conducted. If not already conducted during the participant’s admission evaluation, a 10MWT 
pre-assessment will be conducted by site investigators within 48 hours prior to the first study 
session. A post-assessment 10MWT will be collected within 48 hours of the last study session if 
not already collected by the participant’s primary therapist during that time. 
 
Subject identification, recruitment, and pre-assessments: As described above, qualifying patients 
will initially be screened/identified through internal reports generated at each study site 
summarizing admission BBS scores for recently admitted patients. Screening will continue until 
the target number of participants have completed the study and/or the pre-determined statistical 
guidelines have been met. After initial screening, the additional inclusion/exclusion criteria will be 
considered with attending physician approval and the patient approached for consent. After 
collecting informed consent, participants will be asked to complete an ABC scale pre-assessment. 
If it was not already conducted by the participant’s primary physical therapist at admission, a 
10MWT pre-assessment will be conducted within the 48 hours prior to the first treatment session. 
The admission BBS score will be counted as the participants’ BBS pre-assessment. Study 
procedures and assessments will be conducted according to the general timeline shown in Table 
2. 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

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Table 2. Schedule of Study Procedures and Assessments 
Procedure 
Admission Screening 
Pre-
Intervention 
Treatment Sessions 
Post-
Intervention 
1 
2 
3 
4 
5 
6 
BBS 
X 
 
 
 
 
 
 
 
 
X 
Report generation 
X 
 
 
 
 
 
 
 
 
 
Informed consent 
 
X 
 
 
 
 
 
 
 
 
Participant group assignment  
 
 
X 
 
 
 
 
 
 
 
Collection of demographic and 
other secondary information 
as described below1 
 
 
X 
 
 
 
 
 
 
X 
Additional stroke information1 
 
 
X 
 
 
 
 
 
 
X 
ABC scale 
 
 
X 
 
 
 
 
 
 
X 
10MWT 
 
 
X 
 
 
 
 
 
 
X 
BWSS Control Intervention 
 
 
 
X X X X X X 
 
BWSS-P Intervention 
 
 
 
X X X X X X 
 
TRiP/Perturbation level 
recording 
 
 
 
X X X X X X 
 
System on-time/off-time 
recording 
 
 
 
X X X X X X 
 
Data transfer 
 
 
 
 
 
 
 
 
 
X 
1The described information can be collected, as available, any time after the subject has consented to the study, but 
before de-identified data is transferred to the Lead Site. 
 
Subject assignment: Consented subjects will be assigned to either the BWSS Standard 
Intervention (Control) Group or BWSS with Balance Perturbations (BWSS-P) Intervention Group 
according to a pre-generated randomized assignment sheet. Each randomized assignment sheet 
will consist of equal BWSS Control and equal BWSS-P assignments whose order has been 
randomized using the random list generator at https://www.random.org/lists/. Co-Investigators at 
each site, who will not be delivering the study interventions directly, will be given a unique list with 
a number of assignments that is in proportion to the number of subjects expected to be recruited 
at the site; additional assignment lists will be generated if needed. These co-Investigators will be 
responsible for communicating group assignments to study therapists delivering the intervention, 
and for ensuring that randomization and treatment order is maintained. It is expected that if the 
assignment scheme is not maintained for whatever reason, that they will report the incident to the 
steering committee, described below, and how it was/or still needs to be rectified. No matter group 
assignment, all consented subjects will be asked to conduct all pre- and post-assessments.  
 
BWSS Standard Intervention Control Group: The BWSS control group will conduct at least 2 and 
up to 6 study related therapy sessions. Study related therapy sessions will last a minimum of 15 
minutes up to 30 minutes. Study sessions will be completed over a 2 to 3 week period as part of 
the subject’s inpatient therapy program. Each session must have an active time of at least 15 
minutes in the system to be included, up to 30 minutes for each session. To be as pragmatic and 
clinically relevant as possible, treatment sessions will be incorporated directly into the participants’ 
normal care. Furthermore, we are allowing participants to complete 2 to 6 sessions as dictated 
by short or unexpected changes to the discharge planning timeline. During each session, 
participants will conduct balance exercises, including: marching, side-stepping, retro-ambulation, 
step-taps, and step-ups. They will also conduct various standard gait exercises, including: 
ambulation over the ground, going up and down stairs, and performing sit-to-stand transitions. 
Each of the 2 to 6 study sessions will be part of the subject’s normal course of therapy. As this is 
an active clinical comparison, clinical parameters and progression, other than those described 

NCT05110300 - 6 
 
above, will be determined by the treating therapist (i.e. percent body weight support and use of 
assistive devices) to ensure success and appropriate challenge to the subject.  
 
BWSS-P Intervention Group: The BWSS-P intervention group will also conduct 2 to 6 study 
sessions over a two-week period. Each session must have an active time of at least 15 minutes 
in the system, up to 30 minutes for each session. Participants in the BWSS-P group will conduct 
the same balance and gait exercises as the control group, however, these sessions will include 
eight perturbations, two in each direction (lateral left, lateral right, anterior, and posterior). 
Perturbations will occur while static/standing (lateral, anterior, posterior) and dynamically while 
ambulating (anterior, posterior). Each of the 2 to 6 study sessions will be part of the subject’s 
normal course of therapy. As this is an active clinical comparison, clinical parameters and 
progression, other than those described above, will be determined by the treating therapist (i.e. 
percent body weight support and use of assistive devices) to ensure success and appropriate 
challenge to the subject. The TRiP or perturbation level will be progressed to the point of loss of 
balance, or very near loss, without recovery. The perturbation level should then be then 
decreased by one level for treatment. All 8 perturbations will occur at this level until it is clinically 
appropriate to progress again. The intensity of TRiP perturbation ranges from level 1 to 10, 
minimal to maximum, respectively. 
 
Post-Assessments: After the completion of the subjects’ final BWSS session before discharge, 
investigators will conduct an ABC and 10MWT post-assessment no longer than 48 hours following 
the final session. Follow-up BBS are often completed prior to discharge as part of 
patient/participant’s standard of care. However, in the case that there is an unexpected delay or 
there is a significant length of time until the participant’s discharge, a post-assessment BBS will 
be conducted no longer than 48 hours following the last session. 
 
Data Analysis: Data were analyzed using GraphPad Prism (version 10; GraphPad Software, 
Boston, MA) and RStudio (version 4.2.2, Posit Software, PBC, Boston, MA]) using the car 
package.1  
Descriptive data is reported as mean (95% confidence interval). If hypothesis testing was done, 
data were reported with a p-value, and significance was set at α=.05. The primary outcome 
measures used in our analyses were the BBS, ABC, 10MWT, CMS GG0130 Mobility scores, 
and CMS GG0170 Self-care scores. Data were determined to be missing completely at random 
and were dealt with via complete case analysis and mixed-effects analysis as applicable. Data 
were also assessed for violations in assumptions of their given tests, and were dealt with via 
non-parametric analysis as necessary.  
Categorical data was analyzed using Chi-square testing. Unpaired t-tests or Mann-Whitney U 
tests were utilized as necessary to evaluate between-group differences in continuous outcome 
variables. 
Analysis of covariance (ANCOVA) was used to account for between group differences while 
controlling for covariates.2,3 To evaluate if there were differences between pre- and post-
intervention data, a 2-way analysis of variance (ANOVA) was utilized, with mixed-effects 
analysis being utilized when data was missing. Differences in average improvement by number 
of sessions completed were evaluated using a 2-way ANOVA. Differences in outcome measure 
between testing sites were analyzed using one-way ANOVA or Kruskal-Wallis testing. Multiple 
comparisons were analyzed using, Fisher’s, Dunn’s, Tukey’s multiple comparison tests as 
appropriate. 
 

NCT05110300 - 7 
 
References: 
1. 
Fox J, Weisberg S. An R companion to applied regression. Third edition. Los Angeles 
London New Delhi Singapore Washington, DC Melbourne: SAGE; 2019.  
2.  
Parametric ANCOVA and the Rank Transform ANCOVA When the Data are 
Conditionally Non-Normal and Heteroscedastic - Stephen F. Olejnik, James Algina, 1984 
[Internet]. [cited 2024 Apr 4]. Available from: 
https://journals.sagepub.com/doi/10.3102/10769986009002129 
3.  
Conover WJ, Iman RL. Analysis of Covariance Using the Rank Transformation. 
Biometrics [Internet]. [Wiley, International Biometric Society]; 1982 [cited 2024 Apr 4];38(3):715–
724. Available from: https://www.jstor.org/stable/2530051