The Effects of Targeted Phantom Motor Execution, Prosthetic Embodiment, and Surgical Closure on Phantom Limb Control, and Physical Function in People With Unilateral (Single) Transtibial (Below-the-knee) Amputation
Phase: NA
Conditions: Phantom Limb, Motor Activity, Amputation Stump, Amputation
Sponsor: University of Saskatchewan

1 
 
 
 
 
 
The effects of targeted phantom motor execution, prosthetic embodiment, and 
surgical closure on phantom limb control, and physical function in people 
with unilateral (single) transtibial (below-the-knee) amputation. 
 
 
 
 
 
 
 
 
Study Protocol and Statistical Analysis Plan 
 
 
 
NCT number: Bio_2855 
Document date: July 29th, 2021 
 
 

2 
 
Experimental setup 
This research is a 2-arm, parallel, open label, non-blinded randomized controlled trial comprised of four 
independent but interrelated studies with the same participants. The familiarization phase, enrollment 
verification, obtaining verbal consent to participate, and gathering screening information will be done via 
phone interview. After screening participants, the Medical and Demographic Questionnaire will be 
administered. The participant will be e-mailed a link to complete the following surveys/questionnaires: 
Medical and Demographic questionnaire, Waterloo Footedness Questionnaire to determine their dominant 
lower extremity, and The Survey of Phantom Limb Awareness and Control that is a commonly used 
questionnaire regarding phantom phenomena. The participant can use a smartphone, iPad or computer to 
answer these surveys/questionnaires. Completion of the surveys/questionnaires at the home will respect 
COVID-19 restrictions by diminishing time spent with the researcher. If the participant is not able to 
complete the surveys/questionnaires prior to their first scheduled visit, they will be given the opportunity 
to do at WinPO prior to the physical function evaluation. At the conclusion of the phone interview, the 
researcher will randomly assign participants to the control or exercise groups. Participants in both groups 
will then be scheduled for an in-person baseline visit and an in-person follow up visit at WinPO for data 
collection. The baseline visit will begin with review of expectations and the participant will sign informed 
consent. All information gathered at the phone interview will be reviewed for accuracy. If the participant 
has not answered the questionnaires/surveys prior to their baseline visit, they will be provided an iPad to 
complete the Medical and Demographic Questionnaire, Waterloo Footedness Questionnaire, and The 
Survey of Phantom Limb Awareness and Control. The baseline testing session will be entirely the same for 
participants of both groups. During this session, the researcher will assess participants based on their 
anthropometric variables (i.e. height, weight, body mass index), the morphology of the residual limb (i.e. 
length, circumference, and volume), prosthesis embodiment as measured by TAPES-R and PEmbS-LLA, 
and functional abilities as measured by targeted phantom motor execution and FSST, while recording their 
muscle activities and plantar foot loads. After completion of the baseline testing, the researcher will contact 
Dr. XXXX, to get information with respect to what surgical closure technique was performed for the 
participant.  
There will be a three-week interval between the first and the second (last) testing sessions. Participants 
randomized to the control group will be encouraged to continue with their usual and customary exercise 
program. Participants in the exercise group will be instructed on performing a targeted phantom exercise 
program to be included in their usual and customary exercise program. At the second testing session, the 
same researcher will repeat all baseline measures. All data collection, including screening questionnaires 
and surveys of the study, will be performed through the secure REDCap platform (https://www.project-
redcap.org/). 

3 
 
 
Experimental protocol 
At the beginning of the baseline testing session, the researcher measures participants’ weight and height 
using a scale and stadiometer; the body mass index will be calculated using REDCap programmed formula. 
Then the researcher will survey prosthetic embodiment by asking participants to fill out the revised version 
of the Trinity Amputation and Prosthesis Experience Scales (TAPES-R) and Prosthesis Embodiment Scale 
for Lower Limb Amputees (PEmbS-LLA), which are brief self-administered questionnaires to assess the 
adjustment and interaction of people with amputation to their prosthesis. Then, the researcher will ask 
participants to sit on a chair within parallel bars and remove their prosthesis. The researcher will examine 
the residual limb and places paper skin markers on specific landmarks over their residual limb (i.e. middle 
of the patella, tibial tuberosity, the distal end of the residual limb). Then, participants will stand securely 
inside parallel bars while the researcher captures the shape of their residual limb using a 3D scanner 
(OMEGA Scanner 3D, Willow Wood, Ohio, USA). The morphologic characteristics of the residual limb 
(i.e. length, circumference, and volume) will be recorded. If the participant finds it difficult to stand without 
the prosthesis, the scan will be performed in sitting and note in the assessment. The participant will then 
return to the sitting position and placement for the electromyography (EMG) electrodes (Trigno, Delsys 
Inc., Massachusetts, USA) will be determined on both the intact and amputated limbs based on the standard 
electrode placement guideline. However, for the amputated side, since the length of the muscles has 
changed, the location of the EMG electrodes needs to be determined specifically for each participant based 
on the new muscle bulk and optimal electrical signal activity. Electromyography of the tibialis anterior, 
medial and lateral heads of the gastrocnemius muscle will be recorded for both sides. Electrode locations 
will be marked and photographed to ensure consistency with subsequent testing session recordings. The 
skin will be cleaned using an alcohol pad and electrodes will be attached using paper tape.  
Physical function assessments will be done by performing targeted phantom motor executions and four-
square step test (FSST). Muscle activity will be recorded for the targeted phantom motor executions while 
participants are not wearing their prosthesis. However, the assessment of FSST needs participants to wear 
their prosthesis without EMG recording. The justification for this decision is preventing the risk of injury 
at the skin-prosthesis interface due to electrodes and wires. Foot plantar load will be assessed during 
targeted phantom motor executions and FSST. Participants will rest 2 minutes while sitting in a chair after 
each physical function assessment (4 minutes in total). This time will be used to instruct the participant in 
the testing protocol. Additional time will be provided if requested by the participant. After baseline testing 
is complete, EMG electrodes and sensors for the foot plantar load will be removed. Participants will then 
be informed of their randomization group that was determined earlier (before their baseline assessment) 
using the block and simple randomization techniques.  

4 
 
Collected data for the morphology of the residual limb, phantom phenomena, TAPES-R, PEmbS-LLA, 
physical function assessments, and muscle activities of the first session are baseline data and will be used 
for comparison to the results of the same measurements of the second session. After the first session, 
participants in the exercise group will be enrolled in the targeted phantom limb exercise program in addition 
to continuing with their usual and customary post-amputation care while participants of the control group 
will continue with their usual and customary post-amputation care. Participants in the exercise group will 
be trained on the targeted phantom limb exercise program and will have specific training sessions for three 
weeks at participants’ homes via Zoom (https://zoom.us/). The researcher will make Zoom video calls to 
supervise participants and get assurance that all instructions are followed. After three weeks, participants 
of both groups will attend the test center for the second testing session. For both testing sessions, the same 
researcher captures the shape of the residual limb, surveys the phantom phenomena, TAPES-R, and 
PEmbS-LLA, assesses physical function, and conducts EMG investigations. 
 
 
Data analysis and statistics 
Different levels of comparisons will be done to explore the impact of the targeted phantom motor execution 
program on phantom phenomena and physical function of people with TTA. Before starting analyses, the 
normality of distribution of the quantitative variables will be assessed by the Shapiro-Wilk test. Since there 
are two groups of participants, whether participants are matched on their demographic and clinical 
characteristics will be explored using independent t-test and chi-square statistics. Based on our expectation 
of normality of distribution for the quantitative variables, if it is the case, parametric statistical tests will be 
used. An independent t-test will be used to compare quantitative variables within-subjects for the amputated 
and non-amputated sides. Similarly, Mann-Whitney test and Chi square test will be used respectively to 
compare ordinal and nominal categorical variables within-subjects for the amputated and non-amputated 
sides. An independent t-test will be analyzed to compare quantitative variables between the two groups. 
Similarly, Mann-Whitney test and Chi square test will be used respectively to compare ordinal and nominal 
categorical variables between the two groups.  
Two-way analysis of variance can be used to compare the simultaneous effect of groups assignment and 
prosthesis embodiment on PLC. Similarly, Friedman’s two-way analysis of variance will be used to 
compare the simultaneous effect of group assignment and surgical closure on PLC.  
Spearman’s correlation coefficients will be calculated to explore the potential relationship of phantom 
phenomena responses with participants’ characteristics (i.e. age, weight, height, body mass index, length 
of the residual limb, the circumference of the residual limb, time after amputation, and years of prosthesis 
use). Moreover, the potential relationship of the phantom phenomena responses with participants’ gender, 
type of surgery, and footedness will be explored by point-biserial correlation assessment. The potential 

5 
 
relationship of the phantom phenomena responses with participants’ prosthesis type will be explored by 
partial eta square correlation assessment.  
The linear regression analysis will be used to predict the effect of predictors / independent variables (i.e. 
clinical and demographic characteristics, and participants group) on outcomes / dependant variables (i.e. 
participants’ physical function variables). Logistic regression analysis will be used to predict model of 
phantom phenomena based on participants’ clinical and demographic characteristics, participants’ group 
and physical function measures. Prior to regression analysis, regression assumptions including the 
normality, linearity, homoscedasticity (i.e. having equal variances in residuals of the predictors), and 
absence of multicollinearity (i.e. strong linear correlation between predictors as indicated by the average of 
the variance inflation factor (VIF) greater than 1) will be checked. For all statistical analyses, a p-value less 
than 0.05 will be considered statistically significant. The effect size and confidence intervals will be 
reported alongside other results to provide better judgment for the potential effects. All data will be analyzed 
offline using IBM SPSS software (Version 22.0, IBM Corp, New York, USA).