Early developmental trajectories of the impaired hand in infants with unilateral cerebral palsy.

Aim: To identify developmental trajectories of impaired hand function in infants aged 3 to 15 months with unilateral cerebral palsy (CP).

Method: Sixty-three infants (37 male; median gestational age 37 weeks [interquartile range 30-39.1 weeks]) recruited as part of a randomized trial with a confirmed diagnosis of unilateral CP were included. All infants received early upper limb therapy. The Hand Assessment for Infants (HAI) was completed at baseline and until 12 to 15 months corrected age. Group-based trajectory modelling identified groups with similar trajectories of development of impaired hand function. Multinomial logistic regression determined associations between demographic variables and trajectory membership.

Results: The three-group trajectory model comprised 'low' 29%, 'moderate' 35%, and 'high' 36% functioning groups. The relative risk ratio of being in the low or moderate relative to high group increased by 16% (95% confidence interval [CI] 1.02-1.32) and 14% (95% CI 1.01-1.29) respectively for each 1 week increase in gestational age. Males were more likely to be in the low relative to high group (relative risk ratio 7.22; 95% CI 1.6-32.5).

Interpretation: Three distinct trajectories of development of the impaired hand were identified. Males and infants born closer to term age were at higher risk of being in a low group with little improvement over time, despite receiving early intervention.