What this trial measures

• High Density Electroencephalogram (HD-EEG)Baseline, Day 15, Day 60

  A high-density EEG net placed on participant's heads will be connected to the EEG recording device that measures the electrical potential generated by the participant's brain and recorded on the participant's scalp. After the net is placed on the head, extra leads are placed on the body for measuring electro-cardiography (ECG), electro-oculography (EOG), and electro-myography (EMG). Three tasks will be performed with simultaneous HD-EEG recording in each assessment session on the robot: one is active and passive movements of fingers with the robot; another is robotic vibration of fingers; the third is interactive game playing with the robot. The entire HD-EEG session will last up to 1.5 hours, and the participants will be given multiple breaks throughout the session. Somatosensory and motor evoked responses will be collected and quantified in the form of signal amplitude, power frequency, and localization.

• Transcranial magnetic stimulation (TMS)Baseline, Day 15, Day 60

  TMS is a noninvasive procedure that uses magnetic fields to stimulate nerve cells in the brain in order to map the motor cortex. During the TMS session, the participant will lay down comfortably in a specially designed armchair. The operator will initially place a band around the participant's head that is used for coregistering the participant's anatomy with respect to the location of the TMS coil.

• MRIDay 15

  MRI produces three-dimensional detailed anatomical image of the human brain. The imaging protocol will consist of structural MRI (T1), diffusion MRI (dMRI), and resting-state functional MRI (rs-fMRI) sequences. Scans will be performed on a 3T Siemens Tim Trio (Siemens Healthcare, USA). The entire data collection session will last \~30 min.

• Pegboard TestBaseline, Day 15, Day 60

  This assesses manual dexterity by measuring the time a child needs to transfer 25 cylindrical metal pegs in to 25 holes. The measurement is transfer time in seconds.

• Assisting Hand Assessment (AHA)Baseline, Day 15, Day 60

  The AHA is an evaluation tool that measures and describes how children with an upper limb disability use his/her affected hand (assisting hand) collaboratively with the non-affected hand. The test will be performed for participants up to 12 years of age. The AHA assesses a child's spontaneous and normal way of handling objects when playing. The AHA score ranges from 22 points (hand is not used at all) to 88 points (hand is used as effectively as a normal hand).

• MACS assessmentBaseline, Day 15, Day 60

  The MACS is used to measure children with CP's typical manual performance during daily activities they may encounter. The MACS describes five levels that are determined by a child's own ability to handle objects, and whether or not they need assistance to perform specific activities. The MACS levels form an ordinal scale from I (handles objects easily and successfully) to V (Does not handle objects and has severely limited ability to perform even simple actions).

• Two Point DiscriminationBaseline, Day 15, Day 60

  The Touch Test® consists of two rotating, plastic disks joined together. Around the perimeter of the two disks are plastic rounded tips of the same length and diameter where all tips are paired except one. Paired tips are spaced at standard testing intervals. Participants will place their hands on a table, palms up, and close their eyes. A paired tip or single tip stimulus is applied randomly to the tip of a digit for at least three seconds, and the participant is asked to state whether he/she perceived a one-point or a two-point stimulus. Testing is conducted the same way for the dynamic test, but the stimulus is dragged from the bottom of the finger to the tip. Two-point discrimination is scored as 1 (normal), 2 (fair), and 3 (poor). Monofilament measures touch sensitivity of the tip of all five fingers. Monofilament scores are 1 (normal), 2 (fair), and 3 (poor).

• MonofilamentBaseline, Day 15, Day 60

  Touch sensitivity will be measured at the tip of all five fingers using von Frey monofilaments. The monofilaments consist of a set of plastic filaments with varying diameters. The monofilaments are aligned perpendicular to the skin and pressed down slowly until they started to bend. The monofilaments are held in place steadily for 1.5 seconds before being removed in the same way as they were applied. Participants are instructed to notify the experimenter if they felt any sensation of touch by saying ''yes" or ''no", and are asked to indicate on which finger they felt a sensation by either touching the finger or expressing it vocally. Monofilament scores are 1 (normal), 2 (fair), and 3 (poor).

• ForceBaseline, Day 15, Day 60

  This is measured by Amadeo. This assesses a person's isometric finger and grip strength. The measurement is grip strength in Newton.

• Range of motionBaseline, Day 15, Day 60

  This is measured by Amadeo. This measures the extension and flexion range of individual finger in mm.

• SpasticityBaseline, Day 15, Day 60

  This is measured by Amadeo. This assesses the existence and severity of spasticity with scores of 1 (normal), 2 (fair), and 3 (poor).

• ToneBaseline, Day 15, Day 60

  This is measured by Amadeo. This measures the tension of the finger muscles. Tone scores are measure from 0 (normal) to 4 rigid.

• Hand motion trajectory (aiming & pointing test)Baseline, Day 15, Day 60

  The Aiming \& Pointing test is a computerized task, in which a participant will hold a digitizer pen and slice the digitizer on a tablet to control the movement of a cursor dot to hit a target dot (both dots displayed on a computer/laptop screen). This measures the accuracy of a child's aiming and pointing movements in mm.