Focus of Attention Effects on Motor Performance and Learning in Individuals Post Stroke During Seated Lateral Weight Shifting: A Two-phase Feasibility Study
Phase: NA
Conditions: Cerebrovascular Accident
Sponsor: Western Carolina University

Focus of attention in individuals post-stroke 
Focus of attention effects on motor performance and learning in individuals post stroke 
during seated lateral weight shifting: A feasibility study 
 
December 21, 2020 
 
Ashley Watamura Hyatt, PT, DPT, NCS 
Assistant Professor 
Department of Physical Therapy 
Western Carolina University  
3971 Little Savannah Road  
Cullowhee, NC 28723 
awhyatt@email.wcu.edu  
 
Ann Medley, PT, PhD 
Professor, Director 
School of Physical Therapy 
Texas Woman’s University 
5500 Southwestern Medical Ave. 
Dallas, TX 75235-7299 
smedley@twu.edu  
 
 
Corresponding author: 
Ashley Watamura Hyatt, PT, DPT, NCS, 3971 Little Savannah Road, Cullowhee, NC 28723,       
717-682-9710, awhyatt@email.wcu.edu  
 
 
The authors have no conflict of interest to declare.   
 
Keywords: Stroke, focus of attention, motor learning, seated weight shifting 
 
IRB approval: 
Western Carolina University, reference number 949671-4 
Mission Health, reference number 1124795-3 

* BodiTrak. Model BT1526-8578. Vista Medical Ltd 55 henlow Bay Unit #3, Winnipeg, MC R3Y 1G4 
† iPad. Apple Inc. 1 Apple Park Way Cupertino, CA 95014 
‡ Body Align Pro. serial number 86300861. Motion Unlimited Corporation California. 4362 Modoc Road Unit B Santa 
Barbara CA 93110.   
1 
Focus of attention effects on motor performance and learning in individuals post stroke 
during seated lateral weight shifting: A feasibility study 
Protocol 
Study design 
This was a two phase feasibility study exploring appropriate management, setting, 
participants including inclusion and exclusion criteria, attrition rates, protocol, and 
retention. Outcome data for each stage were collected during baseline, acquisition, short-
term, and long-term retention. The study was approved by the Institutional Review Board 
at both Western Carolina University, reference number 949671-4, and Mission Health 
Systems, reference number 1124795-3. Minimal exertion during the activity was the only 
potential harm for this study. All participants provided written informed consent prior to 
data collection. There were no outside funding sources.  
Study Participants 
During Phase I, participants with history of a chronic stroke (>6 months) and ability to sit 
statically without physical assistance were eligible for the study. Individuals with severe 
hemineglect (star cancellation test <44/54) or inability to follow multistep commands 
were excluded. There were no issues with these criteria during the first phase, so the same 
criteria were used to recruit participants with acute stroke in an inpatient rehabilitation 
setting for Phase II. Unfortunately, some qualified participants were unable to complete the 
task so throughout the study exclusion criteria was modified to individuals with orthopedic 
issues that limited their ability to weight shift including severe hip or back pain, individuals 
with other neurologic conditions such as dementia, and individuals with contraversive 
pushing.  

* BodiTrak. Model BT1526-8578. Vista Medical Ltd 55 henlow Bay Unit #3, Winnipeg, MC R3Y 1G4 
† iPad. Apple Inc. 1 Apple Park Way Cupertino, CA 95014 
‡ Body Align Pro. serial number 86300861. Motion Unlimited Corporation California. 4362 Modoc Road Unit B Santa 
Barbara CA 93110.   
2 
Investigators 
Although the principal investigators were both faculty members at Western Carolina 
University, one of which was a licensed physical therapist, the other investigators were 
student physical therapists. During Phase I, each investigator filled one of three roles 
during data collection for the entire phase: script reading, computer management, or 
patient guarding. Lack of cross-training created difficulty in data collection, therefore in 
Phase II investigators were trained for all roles. Different student groups conducted each 
phase of the feasibility study and were trained primarily by the previous student group. 
Inconsistencies with both instruction and data collection persisted suggesting changes in 
investigator training are necessary prior to a randomized controlled study.   
Setting 
Phase I was conducted with individuals with a chronic stroke in two different outpatient 
clinics. Findings from this phase showed no significant differences between the focus of 
attention groups. These findings along with previous findings in the chronic stroke 
population in other studies12,10,11 suggest there may be more significant differences seen in 
those with acute stroke. Muckel and Merholz were able to show differences in performance 
in focus of attention in those with acute stroke during a similar weight shifting task.15 
Based on these findings, Phase II was conducted in the inpatient rehabilitation setting.  
Recruitment and retention  
Twelve adults with chronic stroke (mean age 61.4 + 13.8 years; 6 months to 13 years post-
unilateral stroke) with good trunk control (Function in Sitting Test mean score 51 + 
2.9/56) were recruited for Phase I. Recruitment of participants was primarily from 

* BodiTrak. Model BT1526-8578. Vista Medical Ltd 55 henlow Bay Unit #3, Winnipeg, MC R3Y 1G4 
† iPad. Apple Inc. 1 Apple Park Way Cupertino, CA 95014 
‡ Body Align Pro. serial number 86300861. Motion Unlimited Corporation California. 4362 Modoc Road Unit B Santa 
Barbara CA 93110.   
3 
outpatient settings, local physical therapy clinics or physician offices, located in a rural 
area, thus the sample size was limited. 
To allow for recruitment of a larger sample than in Phase I, Phase II was conducted in an 
inpatient setting. Participants were recruited via staff physical and occupational therapists 
at the facility. Twenty-six adults post-acute stroke (mean age 61.8+17, 1-10 weeks post 
unilateral stroke), with good trunk control (Function in Sitting Test mean score 51.3+4.4 
out of 56) were recruited.   
Randomization and blinding 
During Phase I, stratified randomization was used based on gender.  Results from a 2013 
study showed significant differences between gender during focus of attention trials 
suggesting the potential need for randomization based on gender.18 Group allocation was 
randomly selected for the first male and first female participants. Each following 
participant was alternately placed in either the internal or external focus of attention 
group. During Phase II, gender-based stratification was not used, to explore whether the 
intervention groups would naturally be comparable based on gender, age, BMI, and 
Function in Sitting Test scores. Instead, a blocked randomization with a random number 
generator (blocks of 10) was used to determine the order of focus group allocation. A 
blinded statistician and a graduate assistant performed the random number generation 
and placed the group assignments into separate envelopes, which were then sealed. Group 
assignment remained in sealed envelopes until after baseline measurements were 
completed. The participants and statistician were blinded for both phases of the feasibility 
study.  
Procedures 

* BodiTrak. Model BT1526-8578. Vista Medical Ltd 55 henlow Bay Unit #3, Winnipeg, MC R3Y 1G4 
† iPad. Apple Inc. 1 Apple Park Way Cupertino, CA 95014 
‡ Body Align Pro. serial number 86300861. Motion Unlimited Corporation California. 4362 Modoc Road Unit B Santa 
Barbara CA 93110.   
4 
During Phase I, individuals in both groups sat unsupported on a hi-lo mat table which was 
adjusted so participants were sitting at 90 degrees hip and knee flexion with feet shoulder 
width apart. Tape marks were used to mark initial set up ensuring standardized 
positioning for each trial. Following baseline trials, all participants watched the same 
instructional video describing lateral weight shifting. The instructions included correct 
mechanics that should be used when weight shifting laterally with focus on correct form 
needed for the movement.  
Testing included baseline, acquisition, short term retention (5 minutes later), and long-
term retention (7-10 days later). Participants performed three trials of seated weight 
shifting to each side at all timepoints. During acquisition, the internal focus group was 
instructed to “shift your weight as much as possible towards your right or left hip without 
using your arms”. The external focus group sat with targets one arm length away at 
shoulder height and were instructed to “shift your body weight as much as possible 
towards the blue/orange target without using your arms.”  During baseline and retention 
trials, adults were instructed to “lean as far as you can to the right/left without using your 
arms.”  During Phase II, the protocol was similar except 6 trials were performed for 
acquisition to potentially improve motor learning, which was not significant in Phase I per 
retention data. Other changes to the protocol included allowing participants to move their 
feet when weight-shifting.  Instructions were also revised. The external focus group was 
told to “move your shoulder as close to the blue/orange target as possible”, while the 
internal focus group was told to “shift your body weight as much as possible towards your 
right/left hip without using your arms.” These instructions were too dissimilar and had 

* BodiTrak. Model BT1526-8578. Vista Medical Ltd 55 henlow Bay Unit #3, Winnipeg, MC R3Y 1G4 
† iPad. Apple Inc. 1 Apple Park Way Cupertino, CA 95014 
‡ Body Align Pro. serial number 86300861. Motion Unlimited Corporation California. 4362 Modoc Road Unit B Santa 
Barbara CA 93110.   
5 
participants thinking about different body areas, shoulder as opposed to hip. The external 
focus instructions were also mixed since the shoulder was mentioned.  
Outcome measures  
A 32X32 array BodiTrak* pressure mat with an 18.125 in x 18.125 in sensing area (1,024 
sensors) was used to measure lateral excursion of center of pressure during each trial for 
both phases. The pressure mat has a 200 mmHg calibration range and up to 150 Hz 
sampling frame rate. During Phase II, a 9.5” X 7.31” X 0.37” 4th generation iPad†, with a 9.7-
inch retina display, was used to record videos of each trial. The iPad has a 1080p HD video 
and 1.2 MP photo camera with autofocus and a 2.4 aperture with video stabilization. From 
this footage, shoulder alignment was measured during seated lateral weight shifting using 
the Body Align Pro app‡, trademarked on Nov. 28, 2014. Markers were placed at the 
acromion bilaterally. Each trial was recorded, and snap shots of the furthest lateral weight 
shift were uploaded into the software. The software then allowed angles to be drawn using 
a line from acromion to acromion compared to a horizontal plumb line (see Figure 1). This 
measurement was used to evaluate the participants ability to move their trunk in 
accordance with the instructions given, keeping their shoulders parallel to the horizontal. 
Validity and reliability tests are currently being conducted for this measurement method. 
Insert Figure 1.  
Data analyses 
To summarize participant characteristics, descriptive data included means and standard 
deviations for continuous variables and counts for categorical variables. Percentages were 
reported to specify whether recruitment and retention goals were met based on power 
analysis. For Phase I, a 2 (group) X 4 (time) repeated measures mixed model ANOVA was 

* BodiTrak. Model BT1526-8578. Vista Medical Ltd 55 henlow Bay Unit #3, Winnipeg, MC R3Y 1G4 
† iPad. Apple Inc. 1 Apple Park Way Cupertino, CA 95014 
‡ Body Align Pro. serial number 86300861. Motion Unlimited Corporation California. 4362 Modoc Road Unit B Santa 
Barbara CA 93110.   
6 
used to examine the whether the demonstration, instructions, and set up differentiated 
between focus of attention groups at the different timepoints of the study. Phase II utilized 
both a 2 (group) X 3 (time) and 2 (group) X 4 (time) mixed model ANOVA to analyze the 
relationship of focus of attention on performance during the different timepoints. Data 
including long term retention trials were examined separately due to high attrition rates. If 
the sphericity assumption was violated, Huynh-Feldt (H-F) and Greenhouse Geisser (G-G) 
corrections were used to correct the degrees of freedom to report F values. When the 
overall model was significant, the post hoc pairwise comparison was used, with a 
Bonferroni correction, to examine differences between every two timepoints in each group. 
Adverse events would be counted as any falls or health issues requiring medical attention 
such as a cardiac event.