Development of a Home-based Self-delivered Prehabilitation Intervention to Proactively Reduce Fall Risk in Older Adults
Phase: NA
Conditions: Mobility Limitation, Aging
Sponsor: University of Florida

Cover Page 
 
O+icial Title: HOMEStudy: Development of a Home-based Self-delivered Prehabilitation 
Intervention to Proactively Reduce Fall Risk in Older Adults    
 
NCT Number: NCT05583578  
 
Document Date:10/18/2023 

IRB Version Date: 3/9/2004 
PI version date: 10/18/2023 
IRB study number: IRB202201802 
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Protocol 
 
1. Project Title 
 
Development of a Home-based Self-delivered Prehabilitation Intervention to Proactively Reduce 
Fall Risk in Older Adults 
 
2. Investigator(s): 
 
Clayton W. Swanson, PhD 
David J. Clark, ScD 
 
Mentor(s): 
Kimberly T. Sibille, PhD 
Todd M. Manini, PhD 
 
3. Abstract: 
The effects of aging are multifaceted including structural and functional impairments of the 
central nervous system which often result in reduced mobility, quality of life, and independence. 
Neurorehabilitation is an effective approach for enhancing motor function, but a challenge for 
this field is the ability to produce sufficient neuroplastic change and lasting behavioral 
improvements. Even in the best clinical settings, it may not be feasible for practitioners or 
patients to dedicate the time and financial resources needed to enact adequate progress. 
Moreover, older adults often do not receive preventative neurorehabilitation. Rather, 
interventions usually follow hospitalization resulting from an adverse event. Development and 
implementation of innovative preventative approaches (prehabilitation) to maintain mobility 
function and independence for aging adults may promote a significant clinical paradigm shift. 
Therefore, the long-term goal of this proposed research is to establish a prehabilitation 
approach to reduce fall risk and preserve mobility function. Prehabilitation has the potential to 
help all older adults particularly prior to major health/life events that are associated with fall risk, 
such as planned surgeries (e.g., joint replacement) and adaptations to ones living environment 
(e.g., moving to a new home). Prior to testing a prehabilitation intervention in those special 
populations, we first seek to conduct a pilot study to develop the protocol, establish feasibility, 
and acquire evidence of preliminary efficacy. Our prehabilitation intervention is designed to be 
self-delivered by individuals in their own home and includes two components: motor imagery of 
complex walking tasks (e.g., movements needed to walk throughout a home), and brain 
neuromodulation via transcranial direct current stimulation (tDCS). Motor imagery incorporates 
both mental imagery and action observation. Mental imagery is the act of mentally rehearsing a 
motor action without physically performing the observed movement(s). Another component of 
motor imagery is action observation, which is the act of visually observing a movement(s) being 
correctly performed. tDCS is a form of non-invasive brain stimulation which delivers a mild 
electrical stimulation via electrodes placed on the scalp. tDCS influences neuronal membrane 
potential, which can make brain neurons more likely to fire in response to a behavioral 
intervention (e.g., motor imagery). Both approaches are intended to promote the effects of 
activity-dependent plasticity and Hebbian learning in the brain (“neurons that fire together, wire 
together”). When motor imagery and tDCS are self-delivered at home with telehealth support, 
there lies the potential to offer a convenient and cost- effective means to proactively improve 
functional mobility in older adults. These approaches may be particularly beneficial for under-
served older adults including those with low socioeconomic status and/or living in rural areas 
where barriers exist in receiving specialized medical services. Thus, home-based therapies offer 

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a unique and pragmatic way to enhance mobility prior to an incident occurring. Moreover, 
through necessity and technological advancements, our capacity to monitor and intervene within 
the home has greatly improved. Providing a necessary framework for new approaches targeting 
mobility and independence for our aging neighbors. To test the following aims for this 
intervention-based pilot study we will collect data from 30 fall prone older adults who will be 
randomly assigned to either an active (i.e., real) or sham (i.e., false) tDCS group.  
4. Background: 
 
Falls are the leading cause of injury related deaths among people over the age of 65. Roughly 1 
in 4 older adults experience a fall annually, with 20-30% of those experiencing moderate- to-
severe injuries, resulting in nearly 30,000 deaths, 3 million emergency room visits, and 800,000 
hospitalizations. Of the falls that occur, 55% happen at home during commonly performed 
activities of daily living. While not all falls require medical attention, those that do, inherit large 
healthcare-related costs with a reported $50 billion spent on fall-related post injury treatments 
for older adults. Aside from expense, diminished mobility within free-living environments poses a 
risk for older adults trying to sustain autonomy and independence. The proposed study is 
significant because falls are largely preventable; however, the current standard of care only 
initiates for recovery, rather than as a preventative measure. Therefore, implementation of 
prehabilitative measures for at risk older adults to safeguard against devastating falls and loss 
of independence are the target population for this research.  
 
For the proposed study, motor imagery (MI) will refer to the combined use of action observation 
and mental imagery. Action observation and mental imagery are frequently implemented to 
promote and enhance motor learning, and particularly effective when practiced in series9. 
Action observation refers to watching another individual perform a task, allowing the observer to 
obtain information about the task requirements and think about the associated motor strategies 
necessary for completion. Mental imagery refers to the mental rehearsing of various actions and 
sensations of a particular task, without physical movement. Studies have shown that practicing 
both types of rehearsing together enhances motor leaning and motor control for upper limb, 
lower limb, and whole-body functional tasks. A recently published report showed that older 
adults recovering from a total hip replacement who engaged in post-surgical MI demonstrated 
greater locomotor improvements two months post-surgery compared to their counterparts 
participating in standard of care rehabilitation. Further, neuroimaging studies have shown that 
MI augments neuronal activity, indicating a robust neural response and exciting possibilities for 
providing safe task-practice and Hebbian neuroplasticity (“neurons that fire together wire 
together”), which involves the reorganization of neural circuits in response to practice and 
experience. We are not proposing that MI is superior to conventional physical practice, but 
rather than MI is a safer alternative for exposing older adults to complex walking conditions in a 
self-delivered home-based intervention. Moreover, we propose that self-administered MI and 
neuromodulation via transcranial direct current stimulation (tDCS) will demonstrate compliance 
and feasibility due to its safety, convenience, and low-cost relative to fall related medical and 
rehabilitation expenses. 
 
Achieving task-specific improvements to motor behavior requires neuroplasticity. Consistently, 
reviews show that MI in motor behavior and motor learning paradigms facilitate activity-
dependent neuroplastic adaptation. For instance, functional brain imaging studies have 
demonstrated overlapping neural networks (e.g., frontoparietal network) and similar neural 
connectivity patterns in primary motor and motor associated brain regions when comparing 
action observation and mental imagery to physical practice. Further, neurophysiological 
adaptations have shown similar increases between MI and physical practice in cortical and 

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spinal excitability for increasingly complex tasks such as performing wrist flexion and extension 
exercises to shooting a free-throw in basketball. Additionally, neuromuscular activation via 
electromyography (EMG) has been observed during imagined (i.e., instructed to abstain from 
physical movement) dumbbell lifting movements. Demonstrating similar muscle activation 
responses (although different activation amplitudes) for nine upper limb muscles fundamental to 
the movement (i.e., agonist, antagonist, synergist, and fixator muscles). Moreover, differential 
EMG responses were recorded for imagined ‘heavy’ vs. ‘light’ dumbbell lifts. Together indicating 
that MI engages common neural circuits, neurophysiological substrates, and neuromuscular 
activation patterns compared to physical performance, which we propose can be leveraged to 
increase activity-dependent neuroplasticity and influence motor performance.  
 
Transcranial Direct Current Simulation (tDCS) is a safe and non-invasive brain stimulation 
technique which induces a relatively weak electrical current to a targeted region of the brain, 
influencing neuronal membrane potential. In the proposed study we will examine feasibility and 
develop a protocol for combining MI with tDCS in a home-based, self-delivered intervention. The 
rationale for combining tDCS with MI is that this approach might provide a more robust 
activation of the neural circuits important to task performance, thus driving a greater 
neuroplastic response. Therefore, when brain circuits are excited simultaneously by MI and 
excitatory tDCS, those circuits may be strengthened to a great extent through Hebbian 
neuroplasticity. Additionally, tDCS appears to be most effective when applied in conjunction with 
task-relevant neural activity and over multiple sessions (as we propose to do). For instance, 
prior studies have shown that excitatory tDCS occurring during a postural stability (i.e., balance) 
MI paradigm significantly improved postural stability performance. Importantly, prior studies 
report that home-based, self-delivered tDCS (alone, not combined with MI) is safe and feasible. 
This literature has evaluated numerous populations spanning multiple neurological conditions 
and impairments (e.g., Parkinson’s disease, ALS, stroke, multiple sclerosis, Alzheimer’s 
disease, Mild Cognitive Impairment, osteoarthritis, fibromyalgia, and depression). There are now 
several review articles describing best practices for home-based, self-delivered tDCS. Among 
the most recent was a review article titled “Supervised transcranial direct current stimulation 
(tDCS) at home: A guide for clinical research and practice”. The proposed objectives will provide 
the necessary experience and pilot data to justify conducting a more robust future study.  
 
5. Specific Aims: 
Aim 1: Establish the feasibility and acceptability of delivering a telehealth-based motor 
imagery and tDCS intervention for improving mobility. Hypothesis 1: Participants will 
effectively self-deliver the motor imagery and tDCS intervention, based on 80% of participants 
demonstrating high rates of compliance, safety, and the usability of the technology. Structured 
questionnaires will be used to assess each component separately for both motor imagery and 
tDCS. 
Aim 2: Determine the extent to which motor imagery and prefrontal tDCS augments 
objective functional mobility outcomes. Hypothesis 2: Participants who receive active as 
opposed to sham tDCS will demonstrate moderate effect sizes (d ≥ 0.72) for functional mobility 
improvement. Specifically, older adults who receive active tDCS will demonstrate shorter sit-to-
stand duration, reduced postural sway area, shorter 360 ̊ turn duration, shorter timed up and go 
duration, and faster gait speed. 
Aim 3: Determine the extent to which motor imagery and prefrontal tDCS influences 
physical activity intensity and sedentary time. Hypothesis 3: Participants who receive active 
as opposed to sham tDCS will demonstrate moderate effect sizes of d ≥ 0.72 for duration of 
walking bouts, intensity of walking bouts (as measured by metabolic equivalents (METs)), and a 
reduction in total daily sedentary time.  

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6. Research Plan: 
 
Study Overview 
This prospective cohort study will incorporate a double-blind, randomized design to assess 
whether home-based MI and active tDCS improves functional mobility and home-based physical 
activity behavior. For this pilot study 34 older adults (aged ≥70 years) with a self-reported risk of 
falling will be randomly assigned to either the active or sham tDCS group. Following the group 
assignment participants will complete six home-based MI intervention visits over a two-week 
period coupled with prefrontal active or sham tDCS. Prior to, and following the home-based 
intervention participants will complete laboratory testing. The first laboratory visit (Baseline Visit) 
will include informed consent, questionnaires, and physical activity monitor placement. The 
second laboratory visit (Pre-Intervention Visit) will include functional mobility testing, 
questionnaires, cognitive testing, and familiarization training for the home-based intervention. 
This visit will also include the removal of the activity monitor. The post-Intervention third 
laboratory visit will include mobility testing, questionnaires, cognitive testing, and application of 
the physical activity monitor for an additional week of activity monitoring. For physical activity 
monitoring participants will wear the activity monitor for 7-9 days prior to and after the 
intervention sessions.  
Up to 34 typical older men and women will be asked to participate in this study. An additional 10 
participants (estimated) may enroll in the intervention but discontinue participation before 
completing the protocol. A larger number (up to 75) may participate in screening by telephone 
and/or onsite but will fail the screening tests and not proceed to the study intervention. 
Participants will undergo the following sequence of events: 
• 
Telephone Screening: Participants will be screened by telephone to determine if they 
meet basic enrollment criteria including age and general health status. If patients 
authorized us to view their medical records, those records may be examined to verify 
absence of exclusion diagnoses, to obtain complete/accurate medication lists. 
• 
Informed Consent and Baseline Visit: Participants who pass the phone screen will be 
invited to participate in on-site baseline visit where informed consent will be obtained.  
Demographic information, physical abilities (i.e., fall risk), cognitive function, 
questionnaires, and health/safety screening will be conducted. This single visit will last 
approximately 1.5 hours. Qualifying participants will be invited to participate in the full 
study. 
• 
Activity Monitor Placement: Participants will have a small and light weight activity 
monitor placed on their right thigh using a clear waterproof adhesive tape at two time 
points during the study. Participants will wear this activity monitor for 7-9 days prior to 
and after the intervention. The monitors are secured in such a way that participants can 
shower and sleep with the monitors secured to their leg.  
 
Pre-Intervention 
Visit (Day 7)
Post-Intervention
Visit (Day 23)
Mobility Testing
Questionnaires
Cognitive Testing 
Activity Monitor 
Placement
Home-based Intervention
(Days 8-22)
Motor Imagery
Active or Sham
tDCS
Baseline Visit 
(Day 0)
Informed Consent
Questionnaires 
Activity Monitor 
Placement
7-9 Days of Activity Monitoring
Questionnaires
7-9 Days of Activity Monitoring
6 sessions over 2 weeks
Return 
Activity 
Monitor
(Day 30)
Mobility Testing
Questionnaires
Cognitive Testing
Training for:
Motor Imagery
tDCS

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• 
Pre-Intervention Visit: Participants will undergo mobility testing while with wearing 
wireless inertial sensors. For mobility testing participants will be asked to complete the 
Mini Balance Evaluation Systems Test (Mini BESTest) which assess 6 different balance 
control systems. Participants will be asked to complete a series of 2-minute walk trials 
either at their natural walking pace, their fast-walking pace, or while performing a 
secondary mental task. Participants will perform a variety of 90-degree, 180-degree, and 
360-degree turns. Participants will complete the clinical test of sensory interaction on 
balance (CTSIB) which is performed by having participants stand with their feet together 
on either a firm or foam surface with their eyes open or closed. Participants will be asked 
to perform the five time sit-to-stand, and the timed up and go test, which requires 
participants to stand up from a seated position then walk three meters, turn around walk 
back to the chair and sit back down. The pre-intervention assessment will last about 2 
hours. Participants will also complete a series of computerized tests assessing cognition. 
Lastly, participants will be trained on how to perform the home-based intervention. This 
will entail how to secure the transcranial direct current stimulation (tDCS) headband, turn 
on and activate the tDCS stimulator, and how to perform the motor imagery paradigm. 
• 
Study Intervention Visits: Participants will attend 6 intervention sessions in which will be 
self-delivered within their own home. They will practice motor imagery tasks comprised 
of watching an individual complete commonly performed motor tasks correctly (i.e., 
standing up and sitting down from a chair, walking throughout a house, turning, walking 
outside) then imagine performing the same task without actually moving their body. 
During this task participants will receive either active or sham transcranial direct current 
stimulation (tDCS) to the frontal portion of their brain. Participants will be asked to 
complete questionnaires about how the motor imagery and tDCS went each day. Each 
session will last approximately 30 minutes. 
• 
Post Intervention Visit: Participants will complete the same testing protocol as the Pre-
Intervention visit. This will include using the wireless inertial sensors to complete the 
Mini-BESTest and measure gait, turning, balance, sit-to-stand, and the timed up and go. 
Participants will complete the same cognitive tests battery as the Pre-Intervention visit 
along with a debriefing questionnaire asking about their thought on the intervention and 
which group (active or sham) they felt they were assigned. Lastly, participants will have 
the activity monitor secured to their thigh for an additional week to measure changes in 
physical activity after completing the intervention. After the week of activity monitoring 
participants will be asked to return the activity monitor to the laboratory.  
_________________________________________________________________________ 
Telephone Screening 
Participants will be screened by telephone to determine if they meet the criteria outlined below. 
Participants who qualify for the study will be informed that any identifiable information collected 
during this study will be securely stored and that they will be given a unique participant 
identification number. Conversely, participants who do not qualify (i.e., screen out) for the study, 
their information will not be stored. 
Inclusion criteria 
• 
Age 70 - 95 years of age 
• 
Self-report having a risk of falling. Fall risk will be determined by asking whether the 
participant has had (and recovered from) a fall related injury in the previous year or had 
fallen two or more times in the previous year or if the participant is afraid of falling 
because of their balance or walking. (This criterion is based on the 2020 NEJM study: “A 
Randomized Trial of a Multifactorial Strategy to Prevent Serious Fall Injuries”)  

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• 
Self-report of “some difficulty with walking tasks, such as becoming tired when walking a 
quarter mile, or when climbing two flights of stairs, or when performing household 
chores.”  
• 
Willingness to be randomized to either study group and to participate in all aspects of the 
study assessment and intervention.  
• 
Living in the community and able to travel to the research site. 
• 
Ability to independently assemble and put on the tDCS headband or incorporate the 
involvement of a willing study partner (e.g., a spouse, family member, or friend) who 
agrees to assist with this task during each home intervention session.  
• 
Access to an internet-connected computer or television capable of playing videos with 
sound located in a quiet area with a comfortable stationary chair.  
• 
Able to provide informed consent. 
 
Exclusion criteria 
• 
Diagnosed neurological disorder or injury of the central nervous system, or observation 
of symptoms consistent with such a condition (spinal cord injury, Alzheimer’s, 
Parkinson’s, stroke, etc.) 
• 
A score of 23 or lower on the Montreal Cognitive Assessment (MoCA)  
• 
Contraindications to non-invasive brain stimulation (e.g., metal in head, wound on scalp) 
• 
Use of medications affecting the central nervous system including, but not limited to, 
benzodiazepines, anti-cholinergic medications, and GABAergic medications. 
• 
Severe arthritis, such as awaiting joint replacement 
• 
Cardiovascular disease that is either uncontrolled or limits participants ability to complete 
light aerobic mobility assessments, lung disease requiring supplemental oxygen, or renal 
disease requiring dialysis; uncontrolled diabetes; terminal illness 
• 
Myocardial infarction or major heart surgery in the previous year 
• 
Cancer treatment in the past year, except for nonmelanoma skin cancers and cancers 
having an excellent prognosis (e.g., early-stage breast or prostate cancer) 
• 
Current diagnosis of schizophrenia, other psychotic disorders, or bipolar disorder 
• 
Difficulty communicating with study personnel (including people who cannot speak 
English) 
• 
Uncontrolled hypertension at rest (systolic > 180 mmHg and/or diastolic > 100 mmHg) 
• 
Bone fracture or joint replacement in the previous six months 
• 
Current participation in physical therapy for lower extremity function or cardiopulmonary 
rehabilitation 
• 
Current enrollment in a clinical trial that may influence the results of either study, 
discretion up to the study investigators.  
• 
Clinical judgment of investigative team 
______________________________________________________________________ 
Informed Consent and Baseline Visit 
 
Upon arriving to the research site, participants will undergo informed consent. We will explain 
the full study protocol including transcranial direct current stimulation, motor imagery, activity 
monitor, and the home-based intervention. 
 
All questions from the phone screening will be repeated, and additional health/medical 
screening criteria will be evaluated. This will include: 
• 
Resting blood pressure   

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• 
Height, weight, age, sex, education level, socioeconomic status 
• 
Medical history 
• 
Obtain list of medications that the participant is currently using 
• 
Montreal Cognitive Assessment (MoCA) 
Following the baseline visit, study staff will evaluate performance/responses relative to the study 
enrollment inclusion/exclusion criteria. Individuals who meet all criteria will be invited to enroll in 
the full study.  
Participants who qualify without exemption will be invited to participate. Participants who agree 
to participate will complete a series of questionnaires and have the activity monitor secured to 
their thigh at the end of the baseline visit or at the participants preferred time. The activity 
monitor will be secured to the participant for 7-9 days prior to the pre-intervention study visit.  
Questionnaires: 
• 
Activities Specific Balance Confidence Scale: 16-item questionnaire that gauge’s 
confidence (on a scale of 0-100%) on various balance and walking tasks relevant to 
household and community ambulation. 
• 
Movement-specific Reinvestment Scale: questionnaire that asks about the extent to 
which a person directs conscious attention to control of movement. 
• 
Trailmaking Test – paper-based test where the person must “connect the dots” between 
numbers or between alternating letters and numbers. 
• 
Sleep quality assessed by the Pittsburgh Sleep Quality Index, which is a questionnaire 
about sleep-related habits and experiences. 
• 
Motor Imagery Questionnaire (revised second edition) (MIQ-RS), which is a 
questionnaire asking about one’s ability to imagine performing self-initiated movements. 
• 
Short Form – 36, which is a set of 36 questions aimed at assessing self-reported measures 
of health. 
• 
Katz Index of Independence – is a set of questions aimed at assessing one’s level of 
independence when performing activities of daily living. 
• 
Montreal Cognitive Assessment – is a rapid screen of cognitive abilities designed to 
detect mild cognitive dysfunction. 
At the discretion of the Principal Investigator, any individual may be deemed ineligible for further 
participation in this study if there are concerns about the individual’s capability to perform study 
procedures or if it may be unsafe for the volunteer to participate in the study. Furthermore, 
minor exceptions to the inclusion/exclusion criteria may be permitted at the discretion of the 
Principal Investigator if those exceptions do not influence participant safety. For example, if a 
participant does not have an internet connection but is able to use a USB drive to watch the 
motor imagery videos. This is important to ensure that individuals are not excluded for 
insignificant reasons and to facilitate meeting enrollment benchmarks. 
___________________________________________________________________________ 
 
Pre-Intervention Visit 
 
Mobility Assessment 
Performance on walking tests will be assessed using wireless inertial sensors, force plates, 
and/or an electronic walkway. The wireless inertial sensors are secured to the body using 
Velcro and elastic straps ensuring a snug placement. Data from the wireless inertial sensors is 
wirelessly streamed to a laboratory computer which allows for offline movement calculations. 

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We will use commercially available wireless inertial sensors (Opal by APDM) and software 
(MoveoExplorer by APDM). 
 
Various assessments of mobility performance will be made during the pre-intervention visit. 
Mobility tasks will include assessments of walking, turning, balancing, and sit-to-stand 
performance. For walking, participants will be asked to complete three, two-minute walks at their 
normal, fast, and while performing a secondary cognitive task (such as walking while counting 
backwards by 7’s). Turning tasks will include, 90 degree turns, 180 degree turns and 360 
degree turns. Balance will be assessed using the Mini-BESTest and the Clinical Test of Sensory 
Integration on Balance (CTSIB). The Mini-BESTest is a 14-item test that assess four domains of 
dynamic balance. The CTSIB includes four 30 second balance trials where participants are 
either standing on the firm ground or on a compliant foam pad with their eyes open or closed. 
Sit-to-stand performance will be assessed via the five time sit-to-stand and timed up and go.  
Cognitive Function Assessment 
We will administer the Cognitive Assessment Battery from Cambridge Brain Sciences, which 
includes up to 12 cognitive tests.  All are short, simple, computer-based assessment that assess 
domains of cognitive such as spatial working memory, response inhibition, and reasoning. 
Specific examples include: 
• 
Digit Span Test – determine the longest list of numbers that a person can remember. 
• 
Visuospatial working memory – remember the sequence and location of items that 
appear and disappear from the screen.  
 
Video, photos, and voice recordings 
 
During this study, videos and/or photos may be taken during to document the functional abilities 
of participants, and for possible use in research presentations or education. We may also use 
voice recordings to capture performance on cognitive assessments such as a verbal fluency 
task performed during walking. At the time of consent, participants will choose what their 
videos/photos/recordings can be used for. We will avoid capturing images of the participants’ 
faces and will obscure or delete any such images. 
___________________________________________________________________________ 
 
Home-based tDCS and Motor Imagery Visits 
 
Motor Imagery Task 
Each of the six motor imagery sessions will include roughly 35 minutes of action observation 
and mental imagery (combined, termed motor imagery) task practice. Participants will be asked 
to sit in a quite location without distraction, on a sturdy chair (not a recliner) in front of a 
computer or television screen. The motor imagery tasks are generated from the clinically based 
functional mobility assessments, which demonstrate strong psychometric properties and 
resemble activities of daily living (e.g., sit-to-stand, 360 ̊ turn, walking and turning, and 
balancing). Additionally, we will incorporate ecologically applicable walking environments such 
as navigating outside spaces (e.g., the home, parking lots, community parks). On their computer 
or television screen participants will actively watch a video of each task being performed 
correctly from both a first- and third-person perspective. Then participants will be instruction to 

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mentally imagine performing the task (Figure 2). Participants will practice action observation 
(“seeing the movement”), and mental imagery (“mentally rehearsing the feelings of the 
movement”) in separate but related trials. This sequence facilitates the vividness of the motor 
imagery practice. For action observation, participants will familiarize themselves to the task by 
watching a video of the test being performed correctly from both perspective (total duration of 1 
min). Participants will then imagine performing the task via action observation from the 1st 
person perspective (1 min) and 3rd person perspective (1 min). Participants will then be 
instructed to close their eyes and imagine performing 
the task via mental imagery, from the 1st person 
perspective then the 3rd person perspective, each for 1 
minute. This will provide participants roughly 5 minutes 
of motor imagery practice per task for a total duration 
of 35 minutes. Participant will be able to pause the 
program between trials if a break or rest is needed. 
 
Home-based tDCS during Motor Imagery Practice  
Participants will be randomized and counterbalanced 
(i.e., equal numbers in each group) to receive either 
active or sham tDCS, which will be delivered 
simultaneously during the motor imagery practice 
sessions. Home-based and self-delivered tDCS has 
been shown to be safe and feasible for both 
neurologically impaired and healthy populations. A 
Soterix Clinical Trials tDCS unit will be used for 
delivery of stimulation. Figure 3 illustrates the tDCS 
head gear, which is easy to place, user friendly, and very 
lightweight. Participants will be provided single-use 
“SNAPpad” sponge electrodes (5x7 cm) which are 
individually sealed and come pre-saturated with the optimal 
amount of conductive saline solution. The electrode 
sponges snap onto a pre-configured “SNAPStrap” head 
gear, which is adjustable for each participants head size 
ensuring a secure and consistent fit for all of the motor 
imagery intervention sessions. To ensure consistency of 
electrode placement throughout the intervention 
participants will be provided hands on instruction during the 
pre-intervention visit and will also be provided instructional 
documentation (i.e., picture diagrams and videos). This will 
ensure participants are familiar with snapping the 
electrodes and placing the headgear while they are at 
home. Participants will also be provided instruction for 
operating the handheld tDCS unit. The unit is very user 
friendly and has large easy to read numbers and interface. 
Figure 2: example of at home 
intervention set-up 
Action Observation
Mental Imagery
tDCS
Instructed to 
imagine standing 
up out of a chair
5 minutes of 
motor imagery (MI)
practice per task
Figure 3. tDCS headband in 
the optimal placement for 
intervention visits 

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Each participant will be given six 
unique (one for each intervention 
session) 5-digit number sequences 
which will be used to initiation the 
stimulation for each intervention 
session. The unique number 
sequences are created using a 
third-party to ensure double-blind 
randomization. Therefore, neither 
the participant nor the researchers 
will know which participants are 
receiving active or sham 
stimulation. 
Active tDCS: Twenty minutes of 
2.0mA direct current through two 
biocarbon rubber electrodes 
encased in saline soaked 5cm2 
sponges placed over the frontal 
cortices at F3 and F4 (based on 
the international “10-20 system” of 
standardized brain electrode 
placement). 2.0mA was  
Sham tDCS: Sham stimulation is 
performed with the same device 
and all procedures will be identical 
except for the duration of 
stimulation. Participants will receive 30 seconds of 2.0mA of direct current stimulation at the 
beginning of each rehabilitation session. Since participants habituate to the sensation of tDCS 
within 30-60 seconds of stimulation, this procedure provides the same sensation of active tDCS. 
Telehealth Support: To ensure participants can place the headband and initialize each tDCS 
session the study staff will coordinate with the participant to ensure a staff member is available 
by telephone to answer any questions. 
Questionnaires: 
• 
CHAMPS Physical Activity Questionnaire for older adults, which assesses weekly 
frequency and duration of various physical activities typically undertaken by older adults. 
• 
Daily Vividness of Imagined Tasks Questionnaire – is a set of questions aimed at 
assessing ones ability to imagine the tasks during the home-based study sessions 
• 
tDCS Sensation Questionnaire – is a set of question assessing the amount of sensation 
for various feelings a participant felt during the tDCS session.  
 
Post Visits 
 
Participants will return to lab approximately 1 day after completing the home-based tDCS and 
motor imagery protocol. The Post-Intervention visit will be very similar to the Pre-Intervention 
visit, including each of the components listed above in the Pre-Intervention Visit section along 
with one additional questionnaire. After the mobility, cognitive assessments, and questionnaire, 
the activity monitor will again be placed on participants thigh for 7-9 additional days of activity 
monitoring. At the conclusion of the 7-9 days (depending on whether the day falls on a 
weekend) participants will be asked to drop off the activity monitor to the laboratory.  
Figure 4. Operating the tDCS unit.  
A) participant will first be instructed to press the 
power button, then number 1 – ‘stimulation’. B) Upon 
placing the headband (shown in Figure 3) 
participants will be provided information regarding 
the contact quality (good, moderate, poor), and 
instructed to press the # sign. C) participants input 
the individualized stimulation code followed by the # 
sign to initiate the stimulation. 

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Questionnaire: 
• 
Debriefing Questionnaire – is a set of question asking whether the participant felt like the 
stimulation and motor imagery influenced their performance. Also, this questionnaire 
asks participants to guess which group they felt they were randomized to. 
 
 
Possible Discomforts and Risks: 
 
For the laboratory-based mobility assessment there is a risk of falling. Falls can lead to injuries 
ranging from minor to serious. It is also possible that participants could experience 
musculoskeletal injury such as an ankle sprain. It is possible that the participant may experience 
fatigue, soreness, and discomfort due to physical activity associated with this study. These are 
unlikely to be worse than what he/she would experience due to increased physical activity 
outside of our study. These are normal responses to exercise and most discomfort would 
generally disappear within a matter of days.  
 
There is a risk that participants may find cognitive and functional tests challenging or 
uncomfortable if they have difficulty succeeding with the tasks.  Participant may feel embarrassed 
if they perform poorly on cognitive tests. Participants may skip any question that they do not wish 
to respond do. 
 
Transcranial direct current stimulation (tDCS) has been used by many prior studies and has an 
excellent record of safety and tolerability. The most often reported effect is tingling or itching 
sensations at the site of electrode placement, which may be accompanied by redness of the skin.  
Some people also report headache or a feeling of fatigue.  All these effects dissipate quickly, and 
tDCS has not been reported to have prolonged negative consequences.  A recent literature 
review article compiled data from all tDCS clinical studies performed from 1998 to August 2010.  
Of 209 studies (172 articles, encompassing almost 4000 subjects), active tDCS and sham tDCS 
did not differ in the frequency of adverse effects that were observed. The most common adverse 
effects were headache, itching, burning sensation (without actual injury), discomfort and tingling, 
occurring in 10-40% of patients regardless of treatment group. Additionally, numerous reviews 
have demonstrated that self-delivered home-use of tDCS is safe and feasible.  
 
This study involves laboratory based physical activity including functional mobility assessments. 
As with all physical activity, there is a risk of adverse events such as injury to 
muscles/bones/joints, cardiovascular events, and falling. To mitigate fall risk participants will be 
continuously spotted by trained research personnel during laboratory based functional mobility 
testing. Specifically, to ensure safety for participants while turning, research personnel will first 
place a gait belt around the waist of participants for best spotting practices. Additionally, personnel 
will be within arm’s reach, facing the participant while moving in the opposite direction of the turn 
to ensure the ability to provide multiple points of contact (i.e., hip and shoulder support) in cases 
of lost balance. Physical activity also may lead to discomfort such as fatigue and muscle soreness 
which are normal occurrences with exercise. This study also involves cognitive assessments. 
There is a risk that participants will be unhappy or embarrassed with their perceived performance 
during the assessments. There is also a slight risk that personal, or health information could be 
revealed inappropriately or accidentally. Depending on the nature of the information such a 
release could upset or embarrass the participant. There are no alternative procedures for this 
study. The only alternative is not to participate. Research participants are free to withdraw at any 
time, with no negative repercussions. 
 

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There is a slight risk that the medical grade adhesive used to secure the activity monitors to the 
thigh might cause skin irritation or a rash. In such instances participants will be asked to stop 
wearing the activity monitor.  
 
8. Possible Benefits: 
 
There is no direct benefit to the participant. 
 
9. Conflict of Interest: 
 
None. 
 
10. Statistical analysis and sample size calculations 
This pilot study is designed to assess feasibility and acceptability of a telehealth-based motor 
imagery and tDCS intervention (aim 1) and to acquire preliminary data to plan and conduct 
power analyses for a larger study (aims 2 and 3). To assess feasibility and acceptability, 
summary statistics will be assessed for compliance, safety, usability, and recruitment measures. 
For aim 2 and 3 we are not hypothesizing statistical significance between active and sham tDCS 
groups but rather anticipate that effect sizes will support a directional effect. Based on the UF 
Older Americans Independence Center (OAIC) Biostatistics Core’s recommendations, we will 
use the following statistical design:  
 
For Hypothesis 1: the future statistical design to inform feasibility and acceptability will be based 
on 80% of participants demonstrating compliance, safety, and usability of technology.  
 
For Hypothesis 2: the future statistical design that will be informed by the present pilot data is a 
two-sample t- test to investigate the pre- and post-intervention functional mobility outcome 
differences for both the active and sham tDCS groups. To assess the size of the observed 
effects between active and sham tDCS, Cohen’s d values will be reported for each functional 
mobility response variable. Effect sizes will be defined as small (d = 0.20), medium (d = 0.50), 
and large (d = 0.80).  
 
For Hypothesis 3: the future statistical design that will be informed by the present pilot data is a 
two-sample t- test to investigate the pre- and post-intervention physical activity time, intensity, 
and sedentary time differences for both the active and sham tDCS groups. To assess the size of 
the observed effects between active and sham tDCS, Cohen’s d values will be reported for 
physical activity time, intensity, and sedentary time. Effect sizes will be defined as small (d = 
0.20), medium (d = 0.50), and large (d = 0.80).  
____________________________________________________________________________ 
Data and Safety Monitoring Plan 
Adverse Event Reporting 
Adverse events will be reported according to the guidelines of the University of Florida 
Institutional Review.  
Reporting within 5 days of the PI becoming aware will apply to adverse events that meet all the 
following criteria: 
• 
Serious 
• 
Unexpected 
• 
Related or the Relationship is “more likely than not”  

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Adverse events will be added to the cumulative event table and reported at continuing review 
when they meet either of the following criteria: 
• 
Serious (but expected) and related or the relationship is “more likely than not”. 
• 
Unexpected (but not serious) and related or the relationship is “more likely than not”. 
A serious adverse event is any adverse event that results in any of the following outcomes:   
• 
death,  
• 
a life-threatening adverse event,  
• 
inpatient hospitalization or prolonging existing hospitalization,  
• 
a persistent or significant disability/incapacity,  
• 
or a congenital anomaly/birth defect.   
Important medical events that may not result in death, be life-threatening, or require 
hospitalization may be considered a serious adverse event when the event may jeopardize the 
patient or subject and/or may require medical or surgical intervention to prevent one of the 
outcomes listed in the definition above. 
An unexpected adverse event is any adverse event that is not consistent with the current 
investigator brochure, protocol, consent form, or is not part of the normal disease progression.  
In addition, known adverse events may occur more frequently than expected.  If so, then this 
meets the definition of “unexpected” and must be reported to the IRB. 
Protection Against Risk 
Staff training: All personnel will be thoroughly trained in the study procedures by the Principal 
Investigator or other appropriate member of the research team and will complete all required 
trainings concerning human subjects research at the University of Florida. 
Health monitoring and medical response: Volunteers at risk of health problems due to recent 
history of medical conditions (e.g., serious cardiac or serious pulmonary conditions) will be 
excluded, as noted above in the inclusion/exclusion criteria. Any adverse events will be 
recorded and monitored as required by our University of Florida Institutional Review Board. 
Subjects will be able to terminate a study session at their request at any time without prejudice. 
Minimization of risk during neurorehabilitation and assessments will be accomplished by 
monitoring vital signs, with prescribed criteria for termination of the testing session. Vital signs 
will be monitored before, during and after assessment.  Contraindications for participation will 
include resting heart rate >100 bpm or <50 bpm, resting systolic blood pressure >180 mmHg or 
<100 mm Hg or resting diastolic blood pressure >100 mmHg.  Indications to terminate physical 
activity will include subject complaints of shortness of breath, light-headedness, dizziness, 
confusion, severe headache, dyspnea or onset of angina. If any of these conditions are greater 
than mild or persist after rest, the patient’s primary physician will be called, and patient referred 
for evaluation. If the patient complains of angina at rest, loss of consciousness occurs, or 
cardiac arrest, emergency medical services through 911 will be called immediately.  Portable 
defibrillators are available. 
Confidentiality: Data will be used only in aggregate and no identifying characteristics of 
individuals will be published or presented. Confidentiality of data will be maintained by using 
research identification numbers that uniquely identify each individual. Safeguards will be 
established to ensure the security and privacy of participants’ study records. Appropriate 
measures will be taken to prevent unauthorized use of study information. Data other than 
demographic information will not use names as an identifier. The research ID number will be 
used. The research records will be kept in a locked room in the study site. The files matching 

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participants' names and demographic information with research ID numbers will be kept in a 
locked file that uses a different key from that of all other files. Only trained and certified study 
personnel will have access to these files, and they will be asked to sign a document that they 
agree to maintain the confidentiality of the information.  Electronic records will be stored on 
password protected network server maintained by the university information technology 
department.  In compliance with the Health Insurance Portability and Accountability Act (HIPAA) 
and the Standards for Privacy of Individually Identifiable Health Information of the Department of 
Health and Human Services, we access personal health information and medical records only 
after receiving signed informed consent. 
Safety during laboratory mobility testing: Participants will wear a gait belt during all mobility 
related tasks. This will better enable the therapist and/or assistants to provide support in the 
event of a loss of balance.  Falls will be tracked and reported to the PI and IRB even if there is 
no injury associated. 
 
Home-based tDCS Safety: Our protocol uses stimulation parameters that are considered 
standard practice, and have been used safely in prior research. The most common side effects 
of tDCS are slight itching, tingling, and reddening of the skin under the electrode. Participants 
typically habituate to itching or tingling sensations within 60 seconds of stimulation. To minimize 
risk associated with tDCS, participants will be asked to monitor and report any discomfort 
following tDCS stimulation sessions. If stimulation sensation is uncomfortable, participants will 
be instructed to remove the tDCS head strap and stop the stimulation. 
 
tDCS has been used extensively in both lab-based and home-based intervention protocols. 
Therefore, safety is well established, and guidelines are available to promote safe usage in both 
settings. A recent review article was published in the leading neuromodulation journal Brain 
Stimulation, entitled “Supervised transcranial direct current stimulation (tDCS) at home: A 
guide for clinical research and practice”. This publication developed an 8-item list of 
recommendations for home-based delivery of tDCS. Here we describe how the proposed study 
addresses each of these points:  
 
1. Electrode Placement: Consult the literature and consider carefully how to best position 
the electrodes to achieve the desired effect. 
The F3-F4 (as designated by the “10-20 system” of standardized brain electrode 
placement) electrode montage that we will use has been widely studied. Based on 
current density models, F3-F4 electrode placement delivers broad and roughly 
symmetrical current flow to the anterior frontal lobes. The intensity and duration settings 
are believed to produce net excitation under both the anode and cathode electrodes 
based on transcranial magnetic stimulation and MRI- based connectivity analysis in 
prefrontal cortex findings.  
2. Monitoring: Participants receiving tDCS remotely should be monitored for as many 
sessions as reasonable to assure that the experimental protocol is being followed 
precisely. 
We will implement this monitoring using a developed plan. This begins by having a 
familiarization session which will occur during the pre-intervention study visit in the 
laboratory. Here the research staff will carefully train the participant to set up the tDCS 
electrodes and headgear. This process is facilitated by using Soterix SNAPpad 
electrodes and SNAPstrap headgear, which are specifically designed for simple home-
based self-administered tDCS. Participants will be asked to take a photo of themselves 
(i.e., a selfie) with the electrode and headgear set up at each session then email/text 

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message the photo to study staff. This will allow staff to view these photos (generally on 
the same day) and provide corrective feedback if necessary.  
3. Tolerability: Adverse events must be recorded. Well-defined procedures should outline 
how to address typical and atypical reported adverse events. If a participant is unable to 
tolerate the pre-specified amperage of stimulation and the study design does not permit 
reduction of the dose, then the participant must be prevented from moving forward in the 
study.  
tDCS protocols have been used on many thousands of research participants around the 
world and have not been linked to serious side effects. Our protocol uses stimulation 
parameters that are considered standard practice and have been used safely in our 
laboratory’s prior research. The most common side effects of tDCS are slight itching, 
tingling, and reddening of the skin under the electrodes. Participants typically habituate 
to these sensations within 30-60 seconds of stimulation. For every session, participants 
will complete a questionnaire that asks about the presence and severity of side effects. 
From prior experiments within our laboratory typical side effects include mild sensations 
of burning or tingling at the stimulation site (e.g., rating of 3 or less on a 10- point scale), 
and/or a mild headache. The latter may be due more to tightness of the headgear 
assembly rather than to the tDCS itself. If a participant is unable to tolerate or for any 
reason does not like the stimulation, we will prevent the participant from continuing the 
study. For such instances they will be documented and included for feasibility outcomes.  
4. Dose: Dose is optimized based on study hypothesis (brain target) and prior work in the 
literature. 
In the present study we will deliver both active and sham tDCS. For active stimulation we 
will deliver twenty minutes of 2.0mA direct current will be administered through two 
biocarbon rubber electrodes encased in saline soaked 5x7 cm sponges placed over the 
frontal cortices at F3 and F4 (based on the international “10-20 system” of standardized 
brain electrode placement). Current inflow will occur on the right (F4), and outflow on the 
left (F3) frontal cortices. 2.0mA was chosen based on prior research demonstrating that 
this parameter helps to reduces neuronal membrane polarization. Sham stimulation is 
performed with the same device and all procedures will be identical except for the 
duration of stimulation. The sham group participants will receive 30 seconds of 2.0mA 
direct current stimulation at the beginning of each rehabilitation session. Since 
participants habituate to the sensation of tDCS within 30-60 seconds of stimulation, this 
procedure provides the same sensation as active tDCS in the absence of any 
meaningful dose of stimulation. It is therefore a highly effective sham procedure. 
5. Training: Standardized training for both the research staff and research participant 
should be required and outlined by the protocol. 
Personnel involved with administering tDCS will receive comprehensive training from Dr. 
Swanson (Principal Investigator) or Dr. Clark (Study Mentor). This will include extensive 
practice of head measurements on foam head models and on other lab members, to 
ensure proper location of stimulation electrodes. They will also have thorough training in 
the use of all related equipment/supplies.  
The research participants will undergo a more focused training pertaining to placement 
of stimulation electrodes and operation of the stimulation device. This process is 
facilitated by using Soterix SNAPpad electrodes and SNAPstrap headgear, which are 
specifically designed for simple home-based self-administered tDCS. Likewise, the 
stimulator itself is designed for ease of use. The participant only needs to enter a six-
digit code on the keypad to initiate the pre-programmed stimulation dosage. We will also 
create training videos that participants can watch at their leisure to review study 
procedures. These videos will be posted online, and if requested provided on a USB 
flash drive.  

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6. Environment: Participants ought to complete treatment sessions in a distraction-free 
setting. 
Participants will be instructed to ensure that the motor imagery/tDCS environment is free 
from unrelated distractions. Pets must be confined to a separate room. Non-study 
related entertainment devices including televisions, radios, or portable music devices 
cannot be used during training. The participant must refrain from conversations so as not 
to be distracted during the training tasks.  
7. Evaluation: Specific research outcomes assessment should be conducted at time points 
decided a priori. 
As described in the Research Plan the primary outcomes are to establish feasibility of 
home-based self-delivered tDCS (Aim 1) and to determine whether active tDCS along 
with MI enhances functional mobility (Aim 2) and physical activity intensity and sedentary 
time (Aim 3).  
8. Minimum Device Specifications: Device monitoring that blocks or moderates stimulation 
if impedance is too great to conduct a current as intended between the electrodes. 
Medical grade materials should be used in the production of any device build that is 
used for research or clinicians. Doses should be delivered by devices with precision and 
accuracy. Device should have a capacity for researchers and clinicians to pre-program 
and lock the dosage that will be delivered to users. Safety features should be 
implemented into a device build to ensure that essential protections are provided to the 
patient. These include the ability to abort a session or limiting the device’s ability to 
stimulate in situations of high resistance. The device should be user friendly and intuitive 
as appropriate for patients with disability (i.e., those with limited vision or cognitive 
ability. Examples include large fonts and texts used on the device and clear indication as 
to how to abort stimulation sessions).  
All the device specifications mentioned here are included in the stimulation device that 
we will use for our study. Our device is manufactured by Soterix Medical Inc, which is a 
worldwide leader in tDCS equipment. We will use the “1x1 tDCS mini-CT” device, which 
is specifically design for convenient and safe at home-delivery of tDCS in clinical trials. 
 
Questionnaire administration: Questionnaire data are collected in secure spaces where the 
interview cannot be overheard. Participants will be informed that they are not required to answer 
questions that they do not wish to answer.