Effect of Brain-Computer Interfaced-Assisted Motor Imagery for Gait Retraining in Stroke Patients
Condition: Stroke
MeSH terms: Stroke
Study type: Interventional

Summary: 
      Currently the process for stroke recovery is slow with majority of its treatments focused
      around physical therapy. Among the many methods employed to facilitate recovery in stroke,
      the use of motor imagery (MI) training may be beneficial towards stroke rehabilitation.

      In the current study, we propose 2 aims. Our first aim is to determine the feasibility and
      efficacy of a novel brain-computer interface-assisted MI train program (BCI-MI) in patients
      with chronic ischemic stroke. This is designed as a proof-of-concept study that only require
      a single-session trial. If patients successfully activate the BCI-MI system without much
      difficulty, our second aim is to enroll patients into a 4-week training program using the
      BCI-MI. Both functional magnetic resonance imaging (fMRI) and transcranial magnetic
      stimulation (TMS) will be done to determine the effects of the 4-week training program.
      Subjects may potentially see improvements in walking gait as preliminary data from previous
      studies have demonstrated positive results.
    

Detailed description: 
      In the first study, we propose 20 subjects who have sustained their first ever haemorrhagic
      or ischaemic subcortical stroke with lower limb impairment more than 9 months prior to study
      enrollment. Subjects will be recruited from the existing patients on the study physician's
      cohort of patients and from referrals from attending physicians. During the initial screening
      visit, it will be ascertained that subject fulfills criteria for participation and informed
      consent will be obtained by study staff. Subjects will be fully briefed in detail regarding
      the experimental procedure, risk and benefits involved and their responsibilities during the
      study.

      Once consent is provided, subjects will undergo a MI-BCI usability session, they will be
      seated comfortably in front of a computer screen. An EEG cap will be comfortably worn over
      the head of the subject to record EEG traces of any activated cortical areas. Subjects will
      then be instructed to perform a mental imagery task whereby they will imagine themselves
      walking properly with their affected leg. The accuracies in classifying correct motor imagery
      from the idle condition from EEG will be recorded for each subject. Subjects who obtain an
      accuracy of more than 57.5% are considered eligible for the MI-BCI training program. Subjects
      eligible for the MI-BCI training will then undergo a series of functional assessments,
      including (1) functional clinical measures (10 meter walk test and Up-to-Go test), (2) gait
      analysis , (3) cortical activity assessment using TMS, and (4) MRI and DTI scan. (5)
      Psychological tests including Beck Depression Inventory, fatigue severity scale, digital span
      test. Before the start of MI-BCI training, subjects will undergo one more MI-BCI session of
      calibration, which will be performed totally the same with BCI usability session to gather
      more valuable data for analyzing. After finishing all 5 assessments and MI-BCI calibration
      session, the MI-BCI training can be started at the frequency of 3 times a week lasting for 4
      weeks. The procedure of MI-BCI training is identical to the one in BCI usability session
      except that a cartoon character in the computer screen will be activated to walk forward if
      subjects successfully perform an accurate mental imagery. Subjects undergoing MI-BCI training
      will be required to perform 160 trials of MI altogether with assigned rest periods (5 mins)
      every 40 trials. Each session will last approximate 45 minutes excluding set-up time. The
      number of times subjects can successfully perform the MI task and the ease in which they are
      able to perform the task will be recorded. Distinct brain signals such as event-related
      desynchronization or synchronization (ERD/ERS) are detectable on EEG for both real and
      imagined motor movements in healthy subjects. Using this technique, MI-BCI, which translates
      the imagination of movements into online commands, provides a promising neural communication
      system for stroke patients who suffer from motor disabilities. We have previously
      collaborated with I2R-A*STAR BCI to design a custom-built BCI software to sync with an EEG
      amplifier. We have demonstrated the efficacy of this custom-built MI-BCI device on upper limb
      stroke impairments, therefore, the procedure and equipment used will be kept identical except
      for the software interface, which shows a cartoon character on the screen. Subjects will
      undergo the same five assessments again at the end of the 4-week's MI-BCI training and 4-6
      weeks after the last session of MI-BCI training, respectively, including (1) functional
      clinical outcome measures (10 meter walk test and Up-to-Go test), (2) gait analysis, (3)
      cortical activity assessment using TMS, and (4) MRI and DTI. (5) Psychological tests
      including Beck Depression Inventory, fatigue severity scale, digital span test.

      The timed up-and-go test is a measurement of mobility. It includes a number of tasks such as
      standing from a seating position, walking, turning, stopping, and sitting down. For the test,
      the person is asked to stand up from a standard chair and walk a distance of approximately 3
      meters, turn around and walk back to the chair and sit down again. The 10 meter walk test is
      a test of walking speed. Timed up-to-go test and 10 meter walk test will be assessed by
      certified physical therapist or trained research staff, and will take approximate 30 minutes
      including set-up time.

      Gait analysis is the systematic study of locomotion. It will be performed in NUH, by a
      certified medical technician or a trained research staff. Subjects will be required to wear
      shorts and the whole trial process might be video-recorded for future analyzing the quality
      of subjects' movement (face will not be captured and consent will be obtained in advance).
      Markers might be worn at various points of reference of the body such as iliac spines of the
      pelvis, ankle malleolus, and the condyles of the knee. Electromyography (EMG) sensors might
      be worn at the area of quadriceps femoris,hamstring, gastrocnemius and tibialis anterior
      muscles for both legs. Gait parameters of temporal and spatial measures and joint kinematics
      will be recorded while the subject is walking along the walkway with a force platform,
      according to the instruction of the medical technician or the trained research staff. Each
      session will last approximate 1 hour including set-up time.

      TMS will be performed to investigate the mechanisms of this training on cortical plasticity
      as indexed by cortical excitability changes. For the MEP study, we will initially adjust TMS
      intensity to achieve a baseline MEP in the tibialis anterior muscle of the leg to about 1 mV
      peak-to-peak amplitude before intervention. Stimulation intensity will be kept constant for
      each subject throughout the study. The MEPs will be recorded in a computer for off-line
      analysis. We will record 10 MEPs for each time and average their peak-to-peak amplitude. For
      the paired pulse stimulation, a first subthreshold conditioning stimulus will be applied,
      followed at a variable interstimulus interval (ISI), by a second suprathreshold stimulus. We
      will use the following ISIs - 2, 3, 4, 6, 9, 10, 12, 15 ms. The percentage of change for each
      ISI before and after treatment will be calculated from the MEPs and will therefore important
      to measure changes in intracortical facilitation and inhibition. Each session will last
      approximate 1 hour including set-up time.

      MRI/DTI scan will be performed at CIRC, NUS. Prior to the scan, all patients will be briefed
      of the test procedure and safety aspects. A medically-trained physician will be on standby
      throughout the procedure. All participants will be scanned on a 3-T GE scanner using a
      standard radiofrequency head coil. Head motion was minimized by foam padding and
      forehead-restraining straps. A T1-weighted high-resolution scan and a set of axial fluid
      attenuated inversion recovery images will be acquired. T1-weighted and fluid attenuated
      inversion recovery images will be realigned and spatially normalized into images of isotropic
      voxel size implemented in Matlab. Each session will last approximate 1 hour including set-up
      time.

      A research staff will administer Beck Depression Inventory (BDI), Fatigue Severity Scale
      (FSS), forward and backward digit span for controlling for confounding effect of cognitive
      improvement in this study.
    

Intervention name(s): MI-BCI
Intervention type(s): Device
Intervention description(s): Subjects will be seated comfortably in front of a computer screen. An EEG cap will be comfortably worn over the head of the subject to record EEG traces of any activated cortical areas. If subjects are able to activate the device and are agreeable to participate in the second phase of the study, they will be enrolled in a 4-week BCI-MI training program of 12 sessions. Subjects will be required to perform 160 trials of MI altogether with assigned rest periods (5 mins) every 40 trials. Each session will last approximate 45 minutes excluding set up time.
Intervention model: Single Group Assignment
Masking: None (Open Label)
Primary purpose: Treatment
Keywords: Stroke; lower extremeties; Brain-computer interface; Motor imagery; Rehabilitation; TMS