Evaluation of the Impact of Laterality on Brain Activation During a Virtual Mirror Therapy Task in Healthy Subjects
Condition: Healthy
Study type: Observational

Summary: 
      The aim of this study is to investigate the differences in brain activation in healthy
      subjects during virtual mirror therapy tasks, depending on the laterality of the task. It
      seems that mirror therapy-related brain activation is greater when the visual feedback
      represents the non-dominant hand. The aim of this study is to highlight brain activation
      profiles during the use of virtual mirror therapy according to the lateralization of the
      feedback.
    

Detailed description: 
      Stroke frequently leads to upper limb deficit. The recovery of motor skills depends on many
      factors including laterality. The literature shows that cerebral activation during motor
      tasks differs depending on whether one is right-handed or left-handed and whether one uses
      the dominant hand or not. These differences probably lead to different recovery mechanisms
      depending on the side of the lesion and the laterality. An imaging technique is particularly
      suitable for exploring these different mechanisms: fNIRS (Functional Near Infra Red
      Spectroscopy). This method allows (like fMRI) to study cerebral neurovascular coupling. It is
      based on the fact that an activated brain region increases its local blood flow. Oxygenated
      (HbO) and deoxygenated (HbR) hemoglobin absorb infrared light and it is then possible to
      identify the cerebral cortical regions involved in a given task. This technique therefore
      makes it possible to study cerebral activation under more ecological conditions than fMRI and
      is thus particularly suitable for exploring rehabilitation techniques.

      This research aims to study and compare in healthy subjects, using an fNIRS apparatus, the
      brain regions involved in a virtual mirror therapy task according to the laterality of the
      task.

      The investigations will be carried out by the principal investigator or by specialized
      technicians from the neurology functional exploration department.

      The acquisition has a duration of 15 minutes, it begins with a rest period of 120 seconds,
      which corresponds to the baseline. two different tasks are performed during the acquisition
      for each subject:

        -  observation of visual feedback of the right hand (RVF)

        -  observation of visual feedback of the left hand (LVF)

      The design is a block design, each task, which has a duration of 20 seconds, is carried out
      10 times per acquisition. There is therefore a total of 20 tasks whose order will be
      randomized.

      Before each acquisition, the movements of the right and left hands (finger flexion and
      extension) are recorded by a camera integrated in the virtual mirror therapy tool. Movements
      are performed at a frequency of 0.5 Hz which appears to be the optimal frequency for
      observing cortical activation using a metronome.

      Between periods of movement, the subject is in a rest position for a period from 15 to 25
      seconds.

      The instructions given to each subject are to observe the visual feedback on the screen and
      not to perform any movement during the acquisition.

      After recruiting the subjects, the study investigator will check the inclusion and exclusion
      criteria.

      If the subject can integrate the protocol, the acquisition will then be planned.

      On the day of the acquisition, the fNIRS acquisition helmet (Brite MKII) will be installed by
      a specialist technician and instructions will be given. The recording is then made.
    

Intervention name(s): Left virtual mirror therapy task; Right virtual mirror therapy task
Intervention type(s): Device; Device
Intervention description(s): the participant is seated on a chair facing the screen of the virtual mirror therapy device. both hands resting under the screen. The participant is asked, for each block of 20 seconds, to observe the visual feedback of the virtual left hand on the screen (flexion / extension movements of the fingers at 0.5 Hz).; the participant is seated on a chair facing the screen of the virtual mirror therapy device. both hands resting under the screen. The participant is asked, for each block of 20 seconds, to observe the visual feedback of the virtual right hand on the screen (flexion / extension movements of the fingers at 0.5 Hz).
Observational model: Cohort
Time perspective: Prospective
Sampling method: Non-Probability Sample
Study population: 
        right handed healthy subjects aged between 18 and 60
      
Keywords: mirror therapy; laterality; cortical activation; functional near-infrared spectroscopy; upper limb