Precision Gait Retraining for Children With Cerebral Palsy
Phase: NA
Conditions: Cerebral Palsy, Gait Disorders, Neurologic
Sponsor: Altec Inc.

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Study Protocol and Statistical Analysis Plan 
 
 
Protocol Title 
Precision Gait Retraining for Children with Cerebral Palsy 
 
Sponsor 
Altec Inc., Natick, MA 01760 
 
ClinicalTrials.gov Identifier 
NCT04717323 
 
Principal Investigator 
Paola Contessa 
 
Version Date 
September 8, 2021 
 
Note: The text below was extracted from the IRB protocols for this study, which were first 
approved on 12/27/2019 for testing at Columbia University and on 07/28/2020 for testing at 
Altec, Inc. 
 
 
 

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Study Protocol 
 
Background  
Cerebral Palsy (CP) is the most common physical disability in the pediatric population, 
resulting in a variety of gait impairments that present functional deficits such as reduced walking 
speed, instability, poor endurance, and in some cases limited or no walking ability. Societal 
impacts are profound and include limited opportunities for socialization, decreased work 
potential, and a lifetime of greater healthcare costs for corrective surgery, orthotics, spasticity 
reduction, and therapy. Effective gait rehabilitation has shown to significantly improve gait, but 
typically requires numerous training sessions with a team of physical therapists and assistants to 
restore coupling between upper- and lower-body segments while also supporting the patient’s 
weight. To relieve the physical therapist of the need to stabilize the patient while augmenting 
limb movement, use of robotic rehabilitation devices to support the patient during gait retraining 
has become increasingly popular and is routinely used in rehabilitation clinics.  
 
Existing robotic rehabilitation devices have two major drawbacks: one is that they constrain 
the trunk and pelvis range of motion to single-plane motion, impeding natural rotation/ 
translation of the pelvis and voluntary execution of natural movements that is necessary for 
effective retraining. The other is that they do not always include the benefits of biofeedback, a 
technology that is underutilized in this population. There is a need to improve robotic 
rehabilitation devices with the ability to support the patient weight (through pelvic assistance) 
while accommodating volitional adaptation of movement and providing biofeedback of trunk 
and limb movement.   
 
Goal of the Overall Study 
Our team of experts in wearable sensor systems and algorithms at Altec, Inc., in collaboration 
with robotics and rehabilitation experts from the RObotics And Rehabilitation Laboratory (ROAR 
Lab) of Columbia University, aim to improve current robotic rehabilitation strategies for CP by 
developing a first-of-its-kind Mobile Pelvic Assist Device (mPAD) for gait retraining. This device 
will provide adaptable guiding forces directly to the pelvis through cable-operated and 
robotically controlled mechanisms to provide rotation and translation of the pelvis in as many as 
6 degrees-of-freedom. The provisional support and guidance to the pelvis in turn frees the 
therapist and child to attend to re-establishing normal limb and trunk movements through 
biofeedback training from advanced wearable sensor technology (surface electromyographic or 
sEMG and inertial measurement unit or IMU sensors). The proposed combination of pelvic 
guidance and biofeedback of adjoining trunk and limb segments will provide adaptability to 
allow the child’s remaining volitional control to be active and allow the therapist to tailor the 
intervention directly to the child’s changing status or specific gait anomalies. 
 
This work is a continuation of the efforts from our collaborators at Columbia University who 
have already succeeded in the design and developments of a Tethered Pelvic Assist Device 
(TPAD) that is uniquely capable of automating the well-established physiotherapy practice of 
using the pelvic location near the center of mass as the focal point for proper stabilization and 
guidance. The study will leverage these successes of a laboratory based TPAD prototype to 
integrate wearable sensors into the TPAD intervention to facilitate gait retraining. 
 
 

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Study Sites 
Data collection will take place in the research laboratories of Altec, Inc. (23 Strathmore Rd. 
01760 Natick, MA) under the supervision of the project PI, Dr. Paola Contessa, and the study 
coordinator, Dr. Serge Roy; and at the CUMC/Harkness Pavilion of Columbia University (180 
Fort Washington Avenue, New York, NY) under the supervision of Dr. Sunil Agrawal. 
 
Specific Aims 
A series of treadmill and over ground walking experiments will be performed with and 
without the TPAD device. These experiments will demonstrate that: 
1) For testing at Altec, Inc. - Wearable technology for measuring body kinematics is effective 
at characterizing gait in controls and/or CP individuals and can be used to provide biofeedback 
during gait.  
2) For testing at Columbia University - Sensor-based biofeedback in conjunction with guiding 
forces applied to the pelvis can be used to facilitate gait retraining in children with CP. 
 
Protocol 
For testing at Altec, Inc.: The subjects will first stand on a treadmill during stationary 
operation and a) stand quietly in place and b) step in place. We will then familiarize the subjects 
with walking on a moving treadmill at the lowest speed and increase the speed until reaching the 
most comfortable walking speed for the subjects. We may include trials where the treadmill speed 
is increased or decreased smoothly in a manner that is comfortable for the subjects, including 
starting from quiet standing or decreasing speed to quiet standing. The subjects will be notified 
before each transition. A monitor (computer or tablet) may be placed in front of the subject to 
display real time biofeedback of body movement or muscle activation from the wearable sensors 
to inform them on how well they are performing the task in the form of visual cues, acoustic cues, 
or more interactive videogames. At the end of each trial, subjects will be administered a brief 
Likert-type questionnaire to survey their perceived level of engagement in the biofeedback. After 
the treadmill tasks, subjects may be asked to walk a 10-meter distance, turn around, and return 
to the starting point on level ground within the laboratory.  
Each trial will be 1-5 minutes long with frequent rest periods. Trials will be performed first 
while holding onto the treadmill support bars and again without holding on (only if the subject 
is comfortable doing so). The subjects will be closely guarded at all times and will be instructed 
that they can hold onto the bars at any time. For additional safety, both the subject and researcher 
will have access to an emergency shutoff switch that stops the treadmill belt from moving. 
 
For testing at Columbia University: The subjects will wear a pelvic brace over shorts and walk 
on a treadmill at a comfortable speed to warm up. Springs and cables will then be attached to the 
brace to apply a gentle force on subjects’ pelvis. The subjects will then be asked to walk on a 
treadmill at the same speed. The force magnitude will be monitored and maintained using 
motors. After this period, springs and cables will be detached from the brace and the subject will 
be asked to walk at the same speed. Overground measures (or over a specialized pressure mat 
that collects gait parameters) may be repeated while cables are attached to the brace and either 
no force or a gentle force is applied to the pelvis. The force magnitude will be monitored and 
maintained using motors.  
Subjects may be asked to repeat these procedures in one session or for up to 5 consecutive 
days. Visual feedback will be provided on a computer screen in front of the patient during the 
treadmill tasks. The feedback will be given based on each individual subject's gait parameters. 

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Involvement of Human Subjects 
Children and adults (male/female; ≥6 y.o.), including healthy controls and individuals with 
CP, will be recruited. 
 
Sex considerations: We plan to recruit equal numbers of males and females to assess possible 
differences between men and women with regards to the expected outcomes of this work. 
 
Age considerations: The proposed work includes children because CP is a congenital disorder 
that typically results in a progressive gait disorder from childhood into adulthood. Gait 
intervention is most effective when started young, or at least before a child’s motor 
developmental sequence has fully matured. We will therefore include children ≥6 y.o. (refer to 
Inclusion/Exclusion criteria for more details). Children younger than 6 will be excluded because 
they are likely to be unable to follow the instructions and comply with the protocol requirements. 
 
Racial/Ethnic origin considerations: We plan to recruit a subject population that includes equal 
participation of minorities and is representative of the racial and ethnic diversity of the greater 
Boston (for testing at Altec, Inc.) and New York regions (for testing at Columbia University). 
 
Recording apparatus: A 16-sensor Trigno Wireless data acquisition system (Delsys Inc., Natick, 
MA) designed for detecting sEMG and IMU signals from single hybrid wireless sensors (TrignoIM 
sensors) will be used for the gait recording sessions. TrignoIM sensors will be located on the body 
during these experiments to record sEMG and IMU signals as described in the Sensor Locations 
section below. Passive reflector markers will be located on anatomical bony landmarks for motion 
capture that will be used to validate sensor-based recordings. Sensor signals from TrignoIM 
sensors will be sampled at 2000 samples/sec using EMGWorks software (Delsys Inc., Natick, MA), 
and interfaced over USB to a PC workstation for post processing. Recordings from motion capture 
data will be triggered from the EMGworks software so that biomechanical variables can be 
compared temporally for accuracy. Footswitch sensors or a pair of shoes with pressure pads may 
be used to record foot pressure while walking. 
 
Sensor locations: The skin area of each sensor location will be prepared using alcohol wipes to 
cleanse the skin surface and repeated tape peels to remove possible superficial contaminants (oil; 
dead skin) so as to improve signal quality. We anticipate placement of no more than 16 sensors 
at any one time on muscle locations such as: gluteus medius, upper-back (trapezius), elbow 
flexors (biceps brachii), hip flexors (rectus femoris), knee extensors (vastus lateralis), and ankle 
dorsiflexors/plantarflexors (tibialis anterior and gastroc-soleus) musculature. 
 
Inclusion/Exclusion Criteria 
 
CEREBRAL PALSY 
 
Inclusion criteria: 
- Adults or Children (age≥6 y.o.) 
- Male or Female 
- Confirmed diagnosis of Cerebral Palsy by a neurologist 
- CT or MRI imaging consistent with clinical presentation 
- Clinical evidence of preserved cognition as determined by the child’s neurologist 

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- Clinical evidence of Mild to Moderate spastic (pyramidal) diplegia as determined by the 
child’s neurologist 
- Gross Motor Function Classification System (GMFS) GMFCS Level II (“walks with 
limitations. Limitations include walking long distances and balancing, but not as able as Level I 
to run or jump; may require use of mobility devices when first learning to walk, usually prior to 
age 4; and may rely on wheeled mobility equipment when outside of home for traveling long 
distances.” 
- Spasticity being controlled by pharmaceutical or surgical correction; or has Modified 
Ashworth scale (MAS) = 0-2 (“More marked increase in muscle tone through most of the ROM 
but affected part(s) easily moved 
- Ambulatory without assistive devices (except for long distances or on uneven terrain) 
- No allergies to skin tape such as Band-Aid 
 
Exclusion criteria: 
- Inability to follow simple instructions in English, or through a Spanish-speaking translator 
- Medical history of other neurological conditions 
- Medical history of cardiac or respiratory complications, or disorders that would place the 
subject at risk for conducting the different motor activities 
- Contractures present in lower limb – evaluated based on Tardieu Scale test where joint range 
of motion is measured during slow velocity movements and where contracture is operationally 
defined as being present if the angle at the end of range is 5-10 degrees less than full range at 
ankle; and 5-20 degrees less than full range at hip and knee 
- Skin disorders that result in open lesions or hyper-sensitive/fragile skin, preventing the use 
of medical-grade adhesive tapes to secure the sensors to the skin 
- Unable to provide Informed Consent from subject and Assent from parent or guardian using 
English ICF 
 
CONTROLS 
 
Inclusion Criteria: 
- Adults or Children (age≥6 y.o.) 
- Male or Female 
- Able to walk independently and without assistive devices 
- No history of musculoskeletal or neurological disorders 
- Able to follow directions in English 
 
Exclusion Criteria:  
- Non-English speaker 
- Unable to walk independently and without assistive devices 
- Medical history of neurological or musculoskeletal conditions (arthritis, spondylosis, etc.) 
- Inability to follow simple instructions 
- Unable to provide informed consent in English 
 
Recruitment Process   
(For testing at Altec, Inc.) Subjects with CP meeting the Inclusion/Exclusion criteria will be 
recruited primarily through posting and flyers at pediatric and adult rehabilitation centers 
working with this population in the greater Boston area which will be publicly displayed and 

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circulated. Control subjects meeting the Inclusion/Exclusion criteria will be recruited primarily 
through posting and flyers in the immediate area around Altec, Inc. at local cafes, shopping malls, 
and fitness centers. 
(For testing at Columbia University) Research flyers will be placed in outpatient practice 
offices, and study info will be listed on the RecruitMe website. Further, pediatric individuals with 
cerebral palsy will be recruited through clinicaltrials.gov listing. 
 
Informed Consent 
All subjects will be properly informed of the purpose of the study by the research team at 
Altec, Inc. or Columbia University. The prospective subjects will have the opportunity to read an 
IRB-approved informed consent form outlining the experimental procedures, risks, and rights as 
a human subject and see the actual equipment demonstrated to them. Written consent will be 
obtained from adults, written parental consent and assent will be obtained from pediatric 
participants. A signed and dated copy of the consent form will be provided to each subject/parent. 
All researchers involved in the experimental procedures and analysis of human subject data as 
outlined in this proposal have training certification on file and are familiar with the appropriate 
Federal guidelines regarding the use of human subjects for research. 
 
Potential Risk and Protection against Risk 
The identifiable risks, which fall into the category of less than minimal physical risks, are 
described below. 
 
1. The primary medical risk includes possible irritation to the skin caused by securing and 
removing the sensors from the skin. The risk is comparable to having a Band-Aid on the skin for 
2 hours and peeling it off. To mitigate this risk, the skin will be inspected before and following 
removal of the sensors and wiped using an alcohol swab. An over-the-counter skin moisturizing 
cream will be available should the subject feel any irritation or dryness at the sensor locations. 
 
2. Some temporary tiredness and muscle fatigue may result from performing the walking 
activities. This risk is similar to a light exercise session and will be minimized by offering frequent 
rest periods and breaks for hydration and rest. 
 
3. Risks of falls. Walking on a treadmill can expose an individual to the risk of falling and 
injuring themselves. This risk is mitigated by constant supervision from a study researcher or 
physiotherapist, frequent breaks, and choice of comfortable walking speed. 
 
4. The risk of electric shock is highly unlikely and greatly minimized because the sensors 
used in this study are wireless and designed to completely isolate the subject from sources of 
electrical current. These circuits ensure subject safety in compliance with United States and 
European EN60601 safety standards for medical instrumentation. They are in compliance with 
CE and FDA Medical Device Standards for allowable leakage currents. 
 
5. A subject may feel slight discomfort during walking when wearing the brace. The brace 
is connected mechanically using springs. Though highly unlikely, a spring could break and stop 
the treadmill suddenly but the chances of this are slim. Subjects and researchers will have ‘Stop’ 
buttons to stop the experiment at any time. 

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6. The risk of infection from respiratory viruses such as COVID-19 may be increased when 
spending considerable amount of time in closed spaces, such as offices and laboratory space. To 
mitigate this risk, precautions following state and CDC guidelines will be followed including: 1) 
phone and in-person screening of the research participants and any researcher involved in data 
collection ahead of testing and on the day of testing using the questionnaire attached; 2) 
temperature check upon arrival; 3) requirement for all individuals involved to maintain at least 
6 feet of physical distance as much as possible, and wear a mask at all times; 4) no more than 3 
individuals including the research participant involved in the data collection at all times; 5) 
perform testing in large spaces; 6) require frequent hand-washing and use of gloves when hands-
on contact is required; 7) cleaning and disinfecting of all testing equipment and high-contact 
surfaces using approved disinfectants before and after each data collection. 
 
6. Confidentiality risk: The file linking subjects’ name to codes will be in paper form and will 
be stored in a locked file cabinet along with signed consent forms. All sensor data will be stored 
on the lab servers for at least 3 years in a password protected folder regarding this project. Access 
will only be available to those working on the project. For cases where data are shared between 
Columbia and Altec, Inc. only de-identified, raw data will be shared. This removes risk that a 
patient's privacy may be compromised. In case the subject gives explicit permission to take photo 
and video recordings during the experiment these will be stored in the password protected 
project folder on the lab servers. All digital data will be identified only by subject codes.  
 
Potential Benefits to the Subjects 
There are no anticipated benefits for subjects in this study aside from the potential benefits to 
the population of individuals with CP in need of improved robotic rehabilitation devices for gait 
retraining if our results lead to a more effective system. 
 
Alternatives to Participation 
This study does not involve medical diagnostics or treatments for which alternatives should 
be offered. 
 
 
 
Data & Statistical Analysis Plan 
 
A series of signal acquisition and processing software will be developed to analyze gait 
temporal metrics and range-of-motion from wearable sensors. We will validate these metrics by 
comparing them to those derived using concurrent motion capture data – considered a gold-
standard. We will adopt a repeated measures design (student’s t-test statistic) which will be 
corrected for possible errors associated with multiple comparisons.  
Testing of pelvic guiding forces and biofeedback is not designed for efficacy, but for 
preliminary prototype studies and early development of concepts. Mixed-design analysis of 
variance followed by post-hoc analysis will be used to determine the effect of the TPAD and 
mobile TPAD on walking.