CIMT has shown great promise in helping children and adults regain lost function in a disabled limb by forcing its use through an intensive motor training program and constraining the unaffected arm with a cast. However, relatively little is known about the underlying mechanisms of CIMT in hemiplegic CP. This project will use an integrated translation model to explore neuroimaging predictors of a positive clinical response to CIMT.

The primary research objective is to evaluate neuroimaging predictors of a positive response to CIMT in children with hemiplegic CP secondary to a middle cerebral artery territory stroke (MCA). A focus on the MCA territory is chosen as (1) it targets children with significant hand impairment who have the potential to benefit from CIMT, (2) is the most common neuropathological subtype, and (3) allows for enhanced homogeneity for the matching of case and comparison groups. The primary research question is: In children aged 7 to 16 years with hemiplegic CP secondary to an MCA stroke, are there neuroimaging predictors of a positive response to CIMT, a positive response being defined by an improvement in the Assisting Hands Assessment (AHA) one month after CIMT?

Neuroimaging predictor variables include laterality index (LI) of the primary M1 and S1 areas on fMRI, IHI evaluated by resting state fMRI, dissociation of the M1 and S1 for the hemiplegic hand measured by fMRI, size and vascular distribution of the MCA lesion with T2 weighted MRI, and white matter tract abnormality with Diffusion Tensor Imaging (DTI). We hypothesize that a negative LI, a non-dissociated M1 and S1, low IHI, small size of infarction, and large size of the contralateral corticospinal tract will predict a positive response to constraint. An evaluation of the neuroimaging predictor variables on the persistence of a positive response to CIMT at 6 months as measured by the AHA will also be explored. A secondary objective will evaluate change in the neuroimaging variables from baseline to one month post CIMT by comparing children in the case group who have received CIMT and a comparison group who are matched on baseline QUEST scores.

Inclusion Criteria:

• Diagnosis of Hemiplegic CP secondary to an MCA infarct
• Age between 7 and 16 years
• Ability to co-operate, understand, and follow simple instructions for neuro-imaging outcome measurement: The functional MRI protocol will require some cooperation and the child will need to lie still in a confined place for approximately 45-60 min.
• No previous CIMT within 12-months of study entry or Botulinum toxin upper limb injections within 6-months of study entry.

Exclusion Criteria:

• None