Constraint‐induced movement therapy in children with unilateral cerebral palsy



Unilateral cerebral palsy (CP) is a condition that affects muscle control and function on one side of the body. Children with unilateral CP experience difficulties using their hands together secondary to disturbances that occur in the developing fetal or infant brain. Often, the more affected limb is disregarded. Constraint‐induced movement therapy (CIMT) aims to increase use of the more affected upper limb and improve bimanual performance. CIMT is based on two principles: restraining the use of the less affected limb (for example, using a splint, mitt or sling) and intensive therapeutic practice of the more affected limb.


To evaluate the effect of constraint‐induced movement therapy (CIMT) in the treatment of the more affected upper limb in children with unilateral CP.

Search methods

In March 2018 we searched CENTRAL, MEDLINE, Embase, CINAHL, PEDro, OTseeker, five other databases and three trials registers. We also ran citation searches, checked reference lists, contacted experts, handsearched key journals and searched using Google Scholar.

Selection criteria

Randomised controlled trials (RCTs), cluster‐RCTs or clinically controlled trials implemented with children with unilateral CP, aged between 0 and 19 years, where CIMT was compared with a different form of CIMT, or a low dose, high‐dose or dose‐matched alternative form of upper‐limb intervention such as bimanual intervention. Primarily, outcomes were bimanual performance, unimanual capacity and manual ability. Secondary outcomes included measures of self‐care, body function, participation and quality of life.

Data collection and analysis

Two review authors independently screened titles and abstracts to eliminate ineligible studies. Five review authors were paired to extract data and assess risk of bias in each included study. GRADE assessments were undertaken by two review authors.

Main results

We included 36 trials (1264 participants), published between 2004 and 2018. Sample sizes ranged from 11 to 105 (mean 35). Mean age was 5.96 years (standard deviation (SD) 1.82), range three months to 19.8 years; 53% male and 47% participants had left hemiplegia. Fifty‐seven outcome measures were used across studies. Average length of CIMT programs was four weeks (range one to 10 weeks). Frequency of sessions ranged from twice weekly to seven days per week. Duration of intervention sessions ranged from 0.5 to eight hours per day. The mean total number of hours of CIMT provided was 137 hours (range 20 to 504 hours). The most common constraint devices were a mitt/glove or a sling (11 studies each).

We judged the risk of bias as moderate to high across the studies.

Key results: Primary outcomes at primary endpoint (immediately after intervention)

CIMT versus low‐dose comparison (e.g. occupational therapy)

We found low‐quality evidence that CIMT was more effective than a low‐dose comparison for improving bimanual performance (mean difference (MD) 5.44 Assisting Hand Assessment (AHA) units, 95% confidence interval (CI) 2.37 to 8.51).

CIMT was more effective than a low‐dose comparison for improving unimanual capacity (Quality of upper extremity skills test (QUEST) ‐ Dissociated movement MD 5.95, 95% CI 2.02 to 9.87; Grasps; MD 7.57, 95% CI 2.10 to 13.05; Weight bearing MD 5.92, 95% CI 2.21 to 9.6; Protective extension MD 12.54, 95% CI 8.60 to 16.47). Three studies reported adverse events, including frustration, constraint refusal and reversible skin irritations from casting.

CIMT versus high‐dose comparison (e.g. individualised occupational therapy, bimanual therapy)

When compared with a high‐dose comparison, CIMT was not more effective for improving bimanual performance (MD −0.39 AHA Units, 95% CI −3.14 to 2.36). There was no evidence that CIMT was more effective than a high‐dose comparison for improving unimanual capacity in a single study using QUEST (Dissociated movement MD 0.49, 95% CI −10.71 to 11.69; Grasp MD −0.20, 95% CI −11.84 to 11.44). Two studies reported that some children experienced frustration participating in CIMT.

CIMT versus dose‐matched comparison (e.g. Hand Arm Bimanual Intensive Therapy, bimanual therapy, occupational therapy)

There was no evidence of differences in bimanual performance between groups receiving CIMT or a dose‐matched comparison (MD 0.80 AHA units, 95% CI −0.78 to 2.38).

There was no evidence that CIMT was more effective than a dose‐matched comparison for improving unimanual capacity (Box and Blocks Test MD 1.11, 95% CI −0.06 to 2.28; Melbourne Assessment MD 1.48, 95% CI −0.49 to 3.44; QUEST Dissociated movement MD 6.51, 95% CI −0.74 to 13.76; Grasp, MD 6.63, 95% CI −2.38 to 15.65; Weightbearing MD −2.31, 95% CI −8.02 to 3.40) except for the Protective extension domain (MD 6.86, 95% CI 0.14 to 13.58).

There was no evidence of differences in manual ability between groups receiving CIMT or a dose‐matched comparison (ABILHAND‐Kids MD 0.74, 95% CI 0.31 to 1.18). From 15 studies, two children did not tolerate CIMT and three experienced difficulty.

Authors’ conclusions

The quality of evidence for all conclusions was low to very low. For children with unilateral CP, there was some evidence that CIMT resulted in improved bimanual performance and unimanual capacity when compared to a low‐dose comparison, but not when compared to a high‐dose or dose‐matched comparison. Based on the evidence available, CIMT appears to be safe for children with CP.

Plain language summary

Constraint‐induced movement therapy in the treatment of the upper limb in children with unilateral cerebral palsy

Review question

Does constraint‐induced movement therapy (CIMT) improve arm and hand use in children with unilateral cerebral palsy (CP)?

What is the aim of this review?

To find out if CIMT helps children with unilateral (hemiplegic) CP to use their hands more effectively.

Key messages

CIMT may work better than another upper‐limb therapy carried out at low intensity (low dose) for improving children’s ability to use both hands together. CIMT appears no more effective than another upper‐limb therapy carried out at a high dose or equal dose. CIMT appears to be safe. More well‐designed research is needed for strong conclusions to be made.

What was studied in the review?

Children with unilateral CP have difficulty using two hands together. Most daily activities need co‐ordinated use of two hands together, so clinicians use CIMT to help children with unilateral CP improve upper‐limb ability. There is no one type of CIMT, although it always involves a constraint (e.g. mitt, sling, cast) on the less affected arm, accompanied by intensive therapy with the more affected arm.

What are the main results of the review?

Thirty‐six studies were found. Children were involved in CIMT from 20 to 504 hours. CIMT studies were divided into three categories.

CIMT compared with a low‐dose comparison group (children had 0 to 25 hours of comparison therapy; and the amount of therapy was much lower than the amount of CIMT)

CIMT may improve bimanual ability (that is, using both hands together; low‐quality evidence) and unilateral capacity (that is, one‐handed ability using the more affected hand; very low‐quality evidence) more than low dose. Three studies reported that a small number of children experienced frustration or refused to wear the constraint, or had reversible skin irritations from casting.

CIMT compared with a high‐dose comparison group (children had more than 25 hours of bimanual therapy or another form of intensive therapy and the amount was less than CIMT)

CIMT appeared no more effective than a high‐dose comparison therapy on bimanual ability (low‐quality evidence) or unimanual capacity (very low‐quality evidence). Two studies reported that some children experienced frustration from participating in CIMT.

CIMT compared with a dose‐matched comparison group (children received the same amount of bimanual therapy as the CIMT group).

CIMT appeared no more effective than dose‐matched therapy on bimanual ability, unimanual capacity (low‐quality evidence) or manual ability (very low‐quality evidence). From 15 studies, two children did not tolerate CIMT and three had difficulty getting used to CIMT.

How up to date is this review?

The review includes studies published up to March 2018.

Authors’ conclusions

Implications for practice

This review found weak evidence that, compared with an intervention carried out at low intensity, constraint‐induced movement therapy (CIMT) is more effective at improving bimanual performance and unimanual capacity in children with unilateral cerebral palsy (CP). CIMT appears no more effective, however, than another upper‐limb therapy that is carried out intensively (i.e. the intensive, high‐dose and dose‐matched comparison interventions). The 17 low‐dose comparison interventions were generally not described in sufficient detail to provide a clear indication of the nature of the intervention, although interventionists in nine studies were occupational therapists, implying that an upper‐limb intervention was included. In contrast, the majority of high‐dose and dose‐matched comparison interventions were intensive, bimanual interventions that were therapist‐led and more clearly defined. Consequently, the outcomes of this review provide support for the implementation of well‐defined, time‐limited, goal‐directed blocks of CIMT or bimanual therapy at an intensity greater than low‐dose comparison interventions (i.e. the intensive, high‐dose and dose‐matched interventions). The challenge now for clinicians is to implement these outcomes into clinical practice and to identify potential barriers and enablers for implementation in their local context (Sakzewski 2014b). Generally speaking, CIMT did not appear to impact body structure and function outcomes, such as grip strength, muscle stiffness and spasticity, and had no consistent effect on quality of life. Although there was minimal research on participation outcomes, it is hypothesised that CIMT and bimanual interventions may not have a direct effect on children’s participation (Imms 2016a).

Although we were unable to examine the impact of different modes of delivery of CIMT, such as signature CIMT (sCIMT), modified CMIT (mCIMT) or hybrid CMIT (hCIMT), our review shows that CIMT can be implemented in a range of modes and settings, that constraint can be achieved using various devices, and the accompanying intervention can be delivered by interventionists other than therapists, including parents and students. Our review indicates that the specific mode of CIMT intervention is a lesser issue than implementation of an intensive, carefully‐targeted and well‐supported programme. However, maintenance of treatment fidelity is essential. Clinicians should ensure that the two key ingredients across all models of CIMT are maintained: 1) restraint of the well‐functioning upper limb (irrespective of device/type); and 2) intensive, structured training (irrespective of type) (Eliasson 2014a). The mean number of hours of CIMT provided across studies was 129 hours (range = 20 hours in Yu 2012 to 504 hours in Sung 2005). We did not identify any study that concluded that short‐term constraint methods, such as occasional hand holding, were effective. No study provided CIMT for a period longer than 10 weeks. Clincians, therefore, should view CIMT as a relatively short‐term intervention that is provided for a defined period, and carefully evaluate outcomes before and after implementation using valid and reliable measures.

The high‐dose and dose‐matched comparison interventions, predominantly intensive occupational therapy and bimanual interventions, offer evidence‐based options for families. As with CIMT, these interventions should be implemented with adherence to intervention fidelity, including the nature of intervention and dose.

It is important for clinicians to educate children and families about the outcomes of this review. CIMT appears to be a safe intervention for children with unilateral CP. Families should feel confident that, on average, active engagement in a well‐defined, intensive program of CIMT or bimanual therapy can lead to improvements in bimanual performance and unimanual capacity. Discussions with families will include the magnitude of the benefit, the uncertainty of long‐term benefits of the blocks of intervention, and the need to continually monitor children’s upper‐limb function and occupational performance to identify appropriate timing of further episodes of intensive, upper‐limb interventions or implementation of alternative means of achieving child‐ and family‐centred goals. It should be emphasised that not all children respond to CIMT (Hoare 2015). The challenge remains for researchers to identify the most appropriate of these interventions to implement with individual children. This review was not able to identify the characteristics of children who could be advised to participate in one or the other of CIMT or bimanual interventions. In the meantime, clinicians should consider the specific goals for individual children and families and choose the most developmentally appropriate, family‐centred, and convenient of these approaches (Hoare 2017). Factors, in addition to child and family characteristics and preferences, which may impact of intervention selection include therapist expertise, costs of implementing the intervention, funding and service delivery models, and resource availability.

Implications for research

The current evidence for CIMT in children with unilateral CP mostly comprises small studies at high or unclear risk of bias, and that use a wide range of outcome measures. Larger, more rigorous and more adequately reported randomised controlled trials (RCTs) in the future should aim to develop sequentially knowledge of the effect of CIMT in children with unilateral CP. Future research is required to address three high‐priority areas for future CIMT research identified by expert consensus (Eliasson 2014a). These are: 1) the effect of age on the treatment effect; 2) the effect of repeated CIMT; and 3) the minimum dosage of CIMT required to impact outcomes. Our findings also indicate that there are no further advantages to be gained by conducting studies of CIMT compared with low‐dose interventions. Efforts to tease out optimal dosage, age effects and other critical questions must focus on intensive delivery of both CIMT and comparison interventions. We also recommend that future studies of CIMT in children with CP undertake cost‐benefit analyses, to determine the impact and cost‐effectiveness of the diverse models of upper‐limb intervention, to assist with future knowledge translation.

Inadequate reporting of both CIMT and comparison interventions was common and substantial in this review. We recommend that future trials use the Template for Intervention Description and Replication (TIDieR) checklist and guideline for reporting interventions (Hoffmann 2014). The TIDieR checklist guides study authors to provide details on the rationale for the interventions included in the study, materials required, procedures followed, and to specify who provided the intervention, modes of delivery, where, when and how much intervention was provided, any intervention tailoring available, modifications made to the intervention during study implementation, and planned and actual intervention adherence or fidelity. This information can be provided as supplementary information or included in a published trial protocol. A full description of all comparison interventions is required.

We located 86 published papers or abstracts (range 1 to 10 per study) reporting findings from the 36 studies included in this review. During the literature search and data extraction process, it was frequently difficult and time consuming to establish whether a publication resulted from an existing study and was a duplicate; reported a separate set of outcomes or contained a subgroup of participants; or was a unique study by the same group of authors. In the Agreements and disagreements with other studies or reviews section of this review, we have identified that other researchers have not recognised multiple publications from the same study and have inadvertently synthesised findings from duplicate publications of the same study. To avoid confusion, future studies of CIMT should consider publishing a single manuscript for reporting study results. At the very least, each publication emanating from the same study using the same cohort or subgroups of children should explicitly refer to previous publications and clearly articulate the relationship of the publication to the study as a whole. Trial registration is frequently mandatory and publication of a study protocol is becoming more common ‐ both will assist systematic reviewers and others synthesising evidence to identify and accurately analyse and interpret findings.

We recommend that all authors of trials investigating CIMT in children with CP follow the CONSORT guidelines for reporting RCTs (Schulz 2010) and the extended HARMS guidelines for reporting adverse events (Ioannidis 2004). Although relatively few adverse events potentially related to the CIMT were reported, only 50% of included studies reported monitoring this outcome and the absence of adverse events cannot be confirmed. Implementation of a standardised method of recording and reporting adverse events would ensure more consistent and deliberate reporting.

The choice of outcome measure should be carefully matched to the expected effect of the intervention in all research evaluating health‐related interventions. We strongly recommend future studies use reliable outcome measures that have been validated for children with CP and their families and are matched to the aims of CIMT ‐ improving unimanual capacity and bimanual performance. Understanding its impact on individualised goals related to self‐care and ability to complete other everyday activities is also relevant to consider. Fifty‐seven outcome measures were used by the 36 included studies included in this review and over half of these were used in a single study. This severely limits the ability to pool data for meta‐analysis, slowing the development of further knowledge in this area of research. Uniform follow‐up periods after completion of CIMT could also be adopted to enable more accurate meta‐analysis of studies. Studies should adhere to the standardised procedures for the administration and scoring of outcome measures. When these procedures are modified, the validity and reliability of the outcome is not maintained and the integrity of the measure is threatened (Eliasson 2014a). Unless studies are investigating the cumulative and longitudinal effects of multiple blocks of CIMT or bimanual therapy (or both), outcome measures should also reflect the potential impact of a short‐term intensive block of upper‐limb activity level intervention. Although CIMT has demonstrated domain‐specific changes in quality of life in some studies included in this review, a single block of CIMT does not aim to change multi‐dimensional constructs such as quality of life (Gilson 2014) or participation (Adair 2015Imms 2016b). Selection of outcome measures in future studies of CIMT should reflect this and efforts should also be made to minimise the potential for assessment burden for children and their families. Research has also repeatedly demonstrated there is no evidence that CIMT either improves, or leads to deterioration in, body function and structure outcomes. Studies could justifiably avoid adding to assessment burden and research waste by refraining from further measurement of these types of variables.

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