Neuroplasticity: why the
early years matter most

The brain's capacity to rewire itself, its neuroplasticity, is greatest in the first years of life. Like many fundamental abilities, the capacity to build hand skills is greatest in this period, so effective therapy should target these years. Much conventional therapy, however, relies on structured movements performed over set repetitions to reach a desired outcome. A young child will not follow a programme of that kind, so reaching them calls for a different kind of practice.

Hand use develops in the early years and into the first years of school

• The longest study of its kind followed 171 children with unilateral cerebral palsy from 18 months to 18 years, with 1,197 repeated assessments of how well they used their affected hand in two-handed tasks. Almost all of the improvement in use of the affected hand happened between 18 months and about five years of age, extending to around seven for the most affected children. (Eliasson et al., 2023)
• From about seven years to eighteen, bimanual performance remained relatively stable across every ability level. (Eliasson et al., 2023) The authors' own recommendation is that hand motor training is delivered in the early preschool period.
• This is not the same as saying training after this point does not work. Intensive, goal-directed upper limb training produces measurable gains in school-aged children and adolescents (Sakzewski et al., 2014; Burgess et al., 2025).

Language is the familiar version of the same principle. A child exposed to a second language from birth acquires it without apparent effort. The same person at thirty can still become fluent, but it takes deliberate study, many more hours, and the result is rarely as complete. Hand function behaves similarly. Improvement after the early window is not impossible, it simply costs far more practice to achieve less.

Why the window exists

• The pathway that carries fine hand control from brain to hand is not fixed at birth. In early infancy both sides of the brain project to both hands, and the connections that survive are the ones that are used. Those that are not used are withdrawn. (Eyre, 2007)
• This makes early hand use competitive rather than passive. Where one side is weaker, the stronger side takes territory the weaker side would otherwise have kept, and the weaker projections are progressively lost. The mechanism has been described as an amblyopia of the corticospinal system, the motor equivalent of a lazy eye. (Eyre et al., 2007)
• The clinical implication is that early activity is not simply practice, it is what determines which connections are kept. This is why international guidance now recommends intervention begin in the first two years rather than waiting for a settled diagnosis. (Morgan et al., 2021)

Therapy has to fit the age it is aimed at

• You cannot easily instruct a young child through sets of repetitions. Development at this age comes from the child's own exploration: attempting different strategies, making errors, and keeping the ones that work. Movements that produce a rewarding result are repeated, and repetition is what strengthens the connection. (Rahlin et al., 2019)
• Practice therefore has to leave room for spontaneous exploration and active problem-solving rather than correcting movement patterns towards a template. (Rahlin et al., 2019)
• This is a shift away from the older view of development as something a therapist coaches a child through. Child and environment are better treated as one interacting system: what a child does depends on what the objects around them invite them to do. (Rahlin et al., 2019)

Conclusion

The evidence points to the importance of early intervention, driven by the peak in neuroplasticity in a young child's brain. That window is open from infancy through the first years of school.

This constrains what the intervention can look like. A young child will not follow a prescribed programme, and the mechanism that builds their hand skills does not require them to. What it requires is frequent, self-directed, trial-and-error practice on tasks the child finds worth doing. The design problem is therefore how to put something in a young child's hands that makes them want to keep going.