Objective To compare efficacy of constraint-induced movement therapy (Baby-CIMT) with bimanual therapy (Baby-BIM) in infants at high risk of unilateral cerebral palsy (UCP).

Study design Single-blind, randomized-comparison-trial that had the following inclusion criteria: (i) asymmetric brain lesion (ii) absent fidgety General Movements, (iii) Hammersmith Infant Neurological Examination below cerebral palsy cut-points, (iv) entry at 3 to 9 months corrected age (CA), and (v) >3 point difference between hands on Hand Assessment Infants (HAI). Infants were randomized to Baby-CIMT or Baby-BIM, which comprised 6 to 9 months of home-based intervention. Daily dose varied from 20 to 40-minutes according to age (total 70-89.2 hours). Primary outcome measure was the HAI post intervention, with secondary outcomes Mini-Assisting Hand Assessment and Bayley III cognition at 24-months CA.

Results 96 infants (51 male, 52 right hemiplegia) born median at 37-weeks’ gestation were randomized to Baby-CIMT (n=46) or Baby-BIM (n=50) and commenced intervention at a mean 6.5 (SD 1.6) months CA. There were no between group differences immediately post-intervention on HAI (mean difference [MD] 0.98 HAI units, 95% confidence interval [CI] 0.94-2.91; p=0.31). Both groups demonstrated significant clinically important improvements from baseline to post-intervention (Baby-BIM MD 3.48, 95%CI 2.09-4.87; Baby-CIMT MD 4.42, 95% CI 3.07-5.77). At 24 months, 64 infants were diagnosed with UCP (35 Baby-CIMT, 29 Baby-BIM). Infants who entered the study between 3 and 6-months CA had greater change in HAI Both Hands Sum Score compared with those who entered at ≥6-months CA (MD 7.17, 95% CI 2.93, 11.41, p=0.001).

Conclusion Baby-CIMT was not superior to Baby-BIM, and both interventions improved hand development. Infants commencing intervention at <6 months CA had greater improvements in hand function.