Six subjects with hemiplegic CP (two female and four male; years old) were included in this study. Two subjects (Subject 4 and Subject 8) were right hemiparetic and the other four subjects were left hemiparetic. Two subjects (Subject 1 and Subject 4) were classified as MACS 1 and the other four subjects (Subject 3, 6, 7, and 8) as MACS 2. Subjects with light impairment of their affected hand that was often hardly noticeable were classified as MACS 1. Subjects classified as MACS 2 had impaired use of their affected hand, but could perform life daily activities adequately through compensatory use of their unaffected hand. Five healthy children (two female and three male; years old) were also included as controls. All the controls were right handed. All children with CP included in this study had a successful MRI scan that identified a single subcortical/cortical lesion affecting their motor area in one of the two cerebral hemispheres. In addition, Subject 3 had undergone a right functional peri-insular hemispherectomy due to intractable epileptic seizures and had a physical shift of 1.3 cm to the right of the brain midline separating the two hemispheres, as verified by the anatomical MRI. The children with CP participated in a 2-week, pirate themed, CIMT camp that took place 5 days a week, 6 h a day, at the Texas Scottish Rite Hospital for Children in Dallas. During CIMT camp, the children took part in group and individual activities such as ball games and painting, focused on improving gross and fine motor skills and increasing independence with activities of daily living under the supervision of occupational therapists. The unaffected arm of each child was immobilized by a removable splint during camp hours, which forced the use of their affected arm during play activities. FNIRS measurements, MACS9 classification, and clinical assessments using the Melbourne assessment of upper limb function,12 and AHA13 of bimanual limb function were performed on each child with CP before, immediately after, and 6 months after therapy. Only Subject 4 missed one fNIRS measurement at 6 months after therapy. The occupational therapists inquired about the children’s affected arm activity levels after therapy and although these varied between subjects no additional therapies or intensive manual training were performed by any subject in the 6 months after CIMT. Control subjects were also measured by fNIRS at the same time points, but no clinical assessments were performed on them. The study was approved by the University of Texas Southwestern Medical Center at Dallas (UTSW) Institutional Review Board protocol (IRB No. 042007-064).