Monaz: Hello, I'm Monaz Mehta, editor in the Cochrane Editorial and Methods department. Cerebral palsy is the most common form of childhood disability, and there are several Cochrane Reviews of therapies that might help the children and their families. These include a review on constraint-induced movement therapy, which was updated in April 2019. We asked lead author Brian Hoare from Monash Children’s Hospital in Australia to tell us about this treatment, and the evidence on its effects.

Brian: A large proportion of children with cerebral palsy, or CP, have unilateral CP, which is also known as hemiplegic CP. This affects muscle control and function on one side of the body and is the focus of our review. Children with unilateral CP find it difficult to use their hands together and will often disregard the more affected arm. Constraint-induced movement therapy, or CIMT, aims to increase use of this arm and improve how children with unilateral CP use their two hands together to perform daily tasks. It’s based on two principles: restraining the use of the less affected arm (for example, using a splint, mitt or sling) and intensive therapeutic practice of the more affected arm.
In our Cochrane review, we look at direct comparisons of CIMT and comparisons against other interventions, which we analyzed in groups depending on the relative dosage of those other interventions. Among a range of outcomes, we were particularly interested in evaluating the effect of CIMT on how children with unilateral CP use their two hands together, which goes by the technical term: bimanual performance.
We found 36 randomised trials from 19 countries, making CIMT the most highly studied intervention in children with CP. There was enormous diversity among the trials including a broad range of constraint devices, models and dosage of therapy; outcome measures; settings; and comparison interventions. The average age of children in the studies was 6 years, with the youngest being just 3 months old and the oldest, 19. While the average duration of the CIMT provided was about 130 hours, there was significant variation; ranging from 20 hours to just over 500 hours; and the duration of daily intervention sessions also varied widely, from 30 minutes to 8 hours. The average length of programs was 5 weeks. 
When assessments were done immediately following intervention, we found low-quality evidence that CIMT is more effective than a low dose comparison for improving bimanual performance. However, it was not more effective for improving bimanual performance when compared with a high dose or dose-matched intervention. A small number of children were unable to tolerate CIMT due to frustration and lack of acceptance of the constraint device, with nine children out of nearly 500 in the trials being unable to continue CIMT. However, overall, CIMT appears to be a safe intervention for children with unilateral CP.
In summary, CIMT may work better than other arm therapy carried out at low intensity for improving children’s ability to use both hands together, but it appears no more effective than other therapies carried out at a high dose or equal dose. The specific mode of CIMT is a lesser issue than implementation of a carefully-targeted and well-supported therapy program. Families should feel confident that, on average, active engagement in a well-defined, intensive program of CIMT or bimanual therapy at an intensity greater than "usual care" can lead to improvements in their child’s hand performance. The challenge now is for clinicians to identify potential barriers and enablers for implementation of these approaches and to bring them into their clinical practice.

Monaz: If you would look to find out more about the various types of CIMT in Brian’s review, you can find the full version online. Just go to Cochrane Library dot com and run a simple search for 'CIMT and CP'.