Aspects of hand use development in infants aged 4 to 18 months with or at risk of cerebral palsy: a longitudinal study

BACKGROUND AND OBJECTIVE Promoting hand use is a key goal in the rehabilitation of infants with or at risk of cerebral palsy (CP). To inform treatment planning, this study aimed to describe aspects of hand use development in these infants aged four to 18 months. METHOD Longitudinal design with repeated measurements using the Hand Assessment for Infants (HAI) from four to 12 months of age. At 18 months of age, the Assisting Hand Assessment (AHA), Both Hand Assessment (BoHA), Peabody Developmental Motor Scale (PDMS-2), and mini-MACS (Manual Ability Classification System) were applied. Descriptive statistics identified developmental trajectories for hand use. Linear mixed models estimated growth curves among infants diagnosed with CP. Associations between HAI scores at six and 8 months and outcomes at 18 months were examined using Spearman rank correlation and regression analyses. RESULTS In total, 41 infants with or at risk of CP participated. Developmental hand use trajectories for each infant showed a clear pattern, with trajectories clustering according to manual ability at 18 months, classified by mini-MACS level for infants with CP (bilateral [n = 17], unilateral [n = 12]) and as "typical manual ability" for infants without CP (n = 12). Growth curve, defined by CP subtype and mini-MACS level at 18 months, showed modest differences between groups in the early months, relatively weak linear improvement in HAI scores over time in infants with higher mini-MACS, steeper gains over time in infants with lower mini-MACS, and a similar pattern with overlapping confidence intervals for the two CP subtype within the same mini-MACS level. A strong negative correlation was found between HAI scores and mini-MACS level. Regression analyses demonstrated a statistically significant and positive association between HAI scores and BoHA, AHA, or PDMS-2 subtest (Visual-Motor Integration) scores. DISCUSSION HAI scores at 6 months of age may indicate the subsequent development of hand use up to 18 months of age. This contributes important knowledge to early treatment planning. The results must be interpreted with caution due to the small sample size. Larger studies are needed before firm conclusions are made.