Clinical Trial Details
— Status: Completed
Administrative data
| NCT number |
NCT05138211 |
| Other study ID # |
REFLEX_HemipareticEMG |
| Secondary ID |
|
| Status |
Completed |
| Phase |
N/A
|
| First received |
|
| Last updated |
|
| Start date |
October 18, 2021 |
| Est. completion date |
April 30, 2022 |
Study information
| Verified date |
October 2022 |
| Source |
Spanish National Research Council |
| Contact |
n/a |
| Is FDA regulated |
No |
| Health authority |
|
| Study type |
Interventional
|
Clinical Trial Summary
Hemiparetic gait is characterized by strong asymmetries that could severely affect the
quality of life of stroke survivors. This asymmetry is due to motor deficits in the paretic
leg and the resulting compensations in the non-paretic limb.
In this study, the investigators aim to evaluate the effect of actively promoting gait
symmetry in hemiparetic patients by assessing the motion and muscular activity of both
paretic and non-paretic lower limbs. To this end, the investigators use a unilateral active
Knee-Ankle-Foot Orthosis able to assist the paretic limb of hemiparetic patients during gait.
The system is able to synchronize its action with the movement of the unassisted joints,
promoting a natural and intuitive interaction. The device generates assistance to induce a
healthy gait pattern on the paretic leg.
The hypothesis is that a proper and natural interaction between the user and the exoskeleton
would enable the patients to consider the robot action as a part of their own gait
capability, improving their gait quality as consequence. Hemiparetic asymmetry is not only
due to impairments in the affected limb, but also it is the consequence of biomechanical
compensatory mechanisms that might arose in the non-paretic leg. The aim of this study is to
assess the adaptation process of the subject to the exoskeleton assistance, and to evaluate
the effects of such human-robot interaction in both paretic and non-paretic legs.
Description:
- Materials: The investigators have developed a Knee-Ankle-Foot orthosis (KAFO) composed of
two joints aligned to the knee and ankle of the user. The length of its bars and the
positions of its braces can be tailored to the anthropometry of different users. The knee
joint is actuated by a DC brushless motor EC-60 flat 408057 (Maxon ag, Switzerland) coupled
with a harmonic drive CSD-20-160-2AGR (Harmonic Drive LLC, EE.UU.). The transmission ratio of
1:60 of this system enables the application of a mean torque of 35Nm. The ankle joint of the
prototype remains non-actuated and unlimited, enabling its free movement in the sagittal
plane. The total weight of the KAFO is about 4kg.
The prototype is equipped with sensors that provide information on system variables that are
used for its control in real-time, such as the flexion angle of the robot joint or the
interaction torque between user and robot. In addition, the gait kinematic of the user is
measured by Inertial Measurement Units (IMUs) and the contact of both feet with the floor by
Force Sensing Resistors (FSRs).
The system uses an Adaptive Frequency Oscillator to estimate the continuous gait phase of the
contralateral limb and synchronically assists the paretic leg by inducing a healthy gait
pattern. The action of the robot depends on the gait phase of the assisted leg: during the
stance phase, the robot reinforces the limb so the system composed of the leg and the
exoskeleton can load the user's weight and not collapse, while during the swing phase the
robot guides the limb's movement according to the Assisted-As-Needed (AAN) paradigm creating
a force tunnel around the prescribed trajectory.
- Procedures:
The experimental protocol is divided in three sessions. During all of them, the patient will
walk on a treadmill commanded by the physiotherapist while wearing a safety harness to avoid
falls and while wearing the robotic exoskeleton in the paretic leg. During the second and
third sessions, electromyography will also be acquired by using surface electrodes (Trigno
System, Delsys Inc.) and according to the SENIAM guidelines. The muscle activity of Rectus
Femoris, Biceps Femoris Long Head, Tibialis Anterior and Medial Gastrocnemius of both legs
will be measured through this method. Each experimental session is described next:
1. - Training session: The patient will wear the robotic exoskeleton to familiarize with
the action of the device. Comfortable and maximum velocities will be identified for each
subject.
2. - Ramp Velocity Session: the session will be divided into five trials: (a) Pre, the
patient will not wear the device; (b) Free, the patient will wear the robot but it is
mechanically decoupled so it will enable the free knee movement; (c) Active, the robot
will assist the gait until 75% maximum gait velocity ; (d) MaxActive, the robot will
assist the gait until maximum gait velocity ; and (e) Post, the patient will repeat the
Pre condition. Velocity will increase from a comfortable velocity to the maximum and
then come back to the comfortable one.
3. - Random Velocity session: the session will be divided into the same trials than the
Ramp Velocity Session.
The difference between RampVel and RandomVel sessions will be the sequence of gait speeds at
which the patient will walk. During RampVel, five velocity steps will be defined from
comfortable to maximum velocity with or without exo (depending on the trial) and coming back
to comfortable velocity. During RandomVel, the same range of velocity will be used, but
defining five steps in the whole range and setting them in a random order. In both sessions,
each gait speed step will last one minute, therefore, all trials will last five minutes.
Trials Free, Active and MaxActive will be also randomly ordered in each session.
Between trials, patients will rest during 10 minutes to avoid summation effects. Each session
will occur in different days, leaving 1 or 2 days in between.
- Intervention providers A physiotherapist and an engineer will be present during the trials.
The first will be responsible of assessing the basal gait of the subjects and evaluating
his/her state while the assistance is provided. The engineer will be responsible of managing
the device and recording the data.
Both researchers monitor fidelity to the intervention by direct supervision.
- Modes of delivery The protocol is provided to one participant at a time. Each patient
completes the protocol once.
- Location Hospital Beata María Ana (Madrid, Spain)
- Tailoring and modifications The protocol remains unaltered across applications. The only
adaptation to patients is the choice of the comfortable and maximum gait speeds for the
trials.
