Cortical and Biomechanical Dynamics of Ankle Robotics Training in Stroke
Condition: Cerebral Stroke
MeSH terms: Stroke
Study type: Interventional

Summary: 
      Reduced mobility is often a long-term problem facing those who have chronic leg weakness
      resulting from stroke. Recent innovations in stroke therapy have applied motor learning
      principles to improve motor skills through regular practice of activities using the weaker
      limb. Because the ankle provides critical torques for normal walking and mobility function,
      impairments at the affected ankle pose a major limitation to achieving optimal mobility
      recovery. To address this we have developed a novel ankle robot (Anklebot) to enhance
      physical therapy for improving walking and mobility after stroke. This computer controlled
      device provides assistance when users cannot complete a movement, but will not assist if the
      user is active.

      Motor learning requires active involvement in task-related practice to mediate brain
      plasticity. While voluntary movement is important to remodel motor control circuits, the
      brain mechanisms of reward and motivation also can play an important role. Core brain
      networks involved in reward and motivation increase a person's involvement with their
      surroundings, to focus attention and to prompt one to approach reward and avoid punishment.
      This increased involvement and the elevated emotions associated with it have been shown to
      enhance performance, memory and learning.

      The purpose of this study is to investigate responses of brain and motor behavior of stroke
      patients who use the Anklebot during a 3-week / 3-session/week motor learning based training.
      These responses are compared to a 3-week delayed entry period in which the participants will
      perform an at-home walking program of equal time. After the 3-week delayed entry walking
      program, subjects are divided into low and high reward-feedback groups. The low
      reward-feedback group receives the Anklebot training with only immediate feedback on target
      successes, without cumulative scores and with minimal social interaction with the
      researchers. The high-reward group receives cumulative scores and ongoing social support, are
      eligible for prizes during each session and at the study's completion. All subjects play the
      games as noninvasive electroencephalography and electromyography record brain and muscle
      activity. In addition to analyzing brain information before and after the Anklebot training,
      ankle motor control and walking functions are also assessed immediately before and after the
      first and last robotic training sessions.
    

Detailed description: 
      After informed consent is obtained, this pilot study will require at least eleven visits for
      all subjects. The first visit will entail screening and eligibility tests that last about 3
      hours and will occur at the VAMC (Veteran's Administration Medical Center) in the Geriatric
      Assessment Clinic (GAC). The second and third visits will last approximately 3 hours at the
      VAMC Human Motor Performance Laboratory and will involve collection of noninvasive EEG,
      surface EMG and ECG, and practice of ankle movements by using the ankle robot to play video
      games. In addition measures of gait and balance function will be assessed pre- and post- the
      Anklebot training. For the next 3-weeks the subjects will take part in an at-home, monitored
      (log) walking program. The next seven visits (the training program) entail further practice
      of ankle movements by using the ankle robot to play video games, collection of motor control
      data but not the collection of any electrophysiological data.. Visit eleven (final) is the
      same as visits 2 & 3.

      Visit 1: Screening evaluations include review of medical records, medical and neurologic
      examinations to determine eligibility. Clinical evaluations will also include the Mini Mental
      State Exam (MMSE) and the Center for Epidemiologic Study (CES-D). Clinical suspicion or
      evidence on these screening instruments of dementia, depression, or other cognitive deficits
      that could interfere with the study will preclude further study evaluation and prompt
      referral to psychiatry or other appropriate health professional for further evaluation. The
      Automated Neuropsychological Assessment Metrics (ANAM) is also administered as a
      comprehensive neuropsychological tool for measuring multiple facets of neuropsychological
      processes that pertain to cognitive function and motor learning. In addition participants
      will be asked to walk 10 meters 3 times across a gait measuring mat at their preferred speed
      while in a safety harness and accompanied (not assisted) by an experienced research
      assistant. This will help determine their deficit severity for grouping during data analysis.
      Finally, a standard neurological examination is conducted by medically credentialed staff.

      Visit 2 & 3 & 11: After study enrollment and medical screening, subjects will be tested with
      the Anklebot while EEG, EMG, and heart rate (ECG) are recorded.

      First, subjects will be fitted with a stretch-lycra cap that houses 64 recessed EEG sensors
      formed from tin. The participant's skin will be lightly abraded or rubbed with the end of a
      Q-tip at each sensor site to remove oil and dead epidermal tissue to establish good
      conductance of the EEG signal. The skin will not be broken. Using a blunt applicator attached
      to a syringe, an FDA-approved non-toxic conducting gel will then be applied through an
      opening in each of the 64 recording sensors to establish continuous contact of the gel
      between the skin at the recording sites and the corresponding sensors. Recording sensors will
      also be positioned on the skin above and below the left eye to monitor eye movements as well
      as on both ear lobes to serve as "non-brain" reference sites. A ground electrode site will be
      applied in the frontal region. The eye-channel and reference sites will be lightly abraded
      with a pad, rubbed with alcohol, and prepared with the conducting gel to enable continuous
      connection between the scalp and the sensor surface. Also, surface EMG electrodes will be
      applied to tibialis anterior, gastrocnemius, and, if needed, the peroneal muscles of the
      paretic leg. Leads for ECG recording will be applied bilaterally to locations immediately
      inferior to the clavicles.

      Once the set-up is complete, subjects will be asked to walk 10 m over an instrumented gait
      mat to record gait parameters during 3 preferred and 3 fastest walking trials. Subjects will
      be asked to repeat these walking tasks while performing a concurrent cognitive task
      consisting of solving and verbally reporting answers to simple arithmetic problems. They will
      wear a gait belt and be attended closely by research staff as they walk and receive seated
      rests as required to prevent fatigue. A second test will measure balance control by recording
      30 second trials of postural sway during quiet standing on a force plate. Three balance
      conditions include eyes open, eyes closed, and eyes open while performing a concurrent
      cognitive task consisting of solving and verbally reporting answers to simple arithmetic
      problems. Seated rests will be provided as needed.

      After baseline functional testing participants will be seated in a chair and the ankle robot
      will be attached to their paretic leg by means of an orthopedic knee brace and an orthopedic
      shoe. Pads and cushioning will be applied as needed for proper fitting, and the knee brace
      will be mounted to the chair for stability. The leg will rest on a cushioned support with the
      knee at 45 degrees and the foot free to move.

      Once the set-up is completed, subjects will be asked to "play" a series of videogames by
      plantar- or dorsi-flexing the paretic ankle to move a corresponding cursor on a computer
      screen in order to hit slowly moving targets. The first game is about two-minutes duration
      and is played without robotic assistance to assess subjects' baseline motor control and
      ability. Subsequently, 6 games of about 4-minutes duration will provide differing levels of
      robotic support to guide or encourage the subjects to complete the prescribed ankle
      movements. The nature and amount of robotic support will be varied across the session to
      promote short-term motor learning and control of the paretic ankle. Upon completion of the
      performance-based training series, a repeat of the two-minute unassisted game completes the
      session.' Finally, subjects will be asked to repeat the postural sway and walking tests as
      before.

      Visits 4-10: participants will be seated in a chair and the ankle robot will be attached to
      their paretic leg by means of an orthopedic knee brace and an orthopedic shoe. Pads and
      cushioning will be applied as needed for proper fitting, and the knee brace will be mounted
      to the chair for stability. The leg will rest on a cushioned support with the knee at 45
      degrees and the foot free to move.

      Once the set-up is completed, subjects will be asked to "play" a series of videogames by
      plantar- or dorsi-flexing the paretic ankle to move a corresponding cursor on a computer
      screen in order to hit slowly moving targets. The first game is about two-minutes duration
      and is played without robotic assistance to assess subjects' baseline motor control and
      ability. Subsequently, 6 games of about 4-minutes duration will provide differing levels of
      robotic support to guide or encourage the subjects to complete the prescribed ankle
      movements. The nature and amount of robotic support will be varied across the session to
      promote short-term motor learning and control of the paretic ankle. Upon completion of the
      performance-based training series, a repeat of the two-minute unassisted game completes the
      session. During these training sessions no electrophysiological data will be acquired, only
      motor control data acquired by the Anklebot itself.
    

Intervention name(s): Anklebot (Ankle Robot)
Intervention type(s): Device
Intervention description(s): Impedance controlled ankle robot provides assistance as needed for participants to perform ankle movements while playing a video game, is used to assist stroke patients to enhance motor recovery
Allocation: Randomized
Intervention model: Factorial Assignment
Masking: None (Open Label)
Primary purpose: Treatment
Keywords: EEG; Robotics (ankle); Motor-learning; Brain Plasticity