What is the threshold dose of upper limb training for children with cerebral palsy to improve function? A systematic review

Introduction Neuroplasticity is harnessed through high-intensity or high-dose training. Given the costs and time burden for families of children with cerebral palsy (CP), it is important to quantify which rehabilitation training approaches and doses confer the largest clinical gain. The main objective of this systematic review was to determine any threshold dose of upper limb training needed for children with CP to achieve clinically significant functional improvements. Methods This systematic review included studies if they were as follows: randomised controlled trials; participants had a diagnosis of CP or brain injury; mean age of participants was 0-18 years; and intervention was an active upper limb training intervention. Two raters independently extracted data. Data were pooled and analysed using a receiver operator characteristic (ROC) curve and odds ratios to investigate the dose of practice that led to clinically significant gains. Results A total of 74 trials were included in this review. Quantitative analyses included 25 studies (707 participants; age range 18 months to 21 years) for motor function (Assisting Hand Assessment) and 20 studies (491 participants; age range 3 months to 17 years) for individual goal achievement (Canadian Occupational Performance Measure). ROC curve analyses found that approximately 40 hr of practice is needed to improve upper limb motor ability in the unilateral population. For all typographies of CP, individual goals were achieved at a lower dose (14-25 hr) of practice when goal-directed interventions were provided. Conclusion To improve individual goals, children need to practice goals for more than 14-25 hr, combining face-to-face therapy with home practice. To improve general upper limb function (based on evidence in the unilateral population), children need to practice for more than 30-40 hr. Interventions that set functional goals and involve actual practice of those goals lead to goal achievement at a lower dose than general upper limb motor training.