Longitudinal Hammersmith Infant Neurological Examination (HINE) Trajectories in Children with Cerebral Palsy Identified in High-Risk Follow-Up

<b>Background/Objectives</b>: The Hammersmith Infant Neurological Examination (HINE) is a standardized neurologic exam for infants between 2 and 24 months. Scores can be compared to optimality cutoffs as one component to support an early diagnosis of cerebral palsy (CP). Some prognosis is also possible for infants diagnosed with CP. We aimed to understand the longitudinal trajectories of HINE scores in infants who were ultimately diagnosed with CP. <b>Methods</b>: Clinical records were reviewed for children who were diagnosed with CP in two high-risk infant follow-up clinics with HINE scores from at least two visits between the corrected ages of 3 months and 2 years. Trajectories were calculated individually and by group for infants in four categories-term neonatal hypoxic ischemic encephalopathy (HIE), term perinatal arterial ischemic stroke (PAIS), premature infants with brain injury, and "Other" (term infants with congenital malformations and/or congenital hydrocephalus). The changes in HINE scores between clinic visits were compared using linear mixed-effect models with a random intercept, pulling data by diagnostic group across visits and accounting for within-child correlations of scores over the follow-up time. <b>Results</b>: The changes in HINE scores for sixty children (twenty-five with prematurity, eighteen with HIE, seven with PAIS, and ten in the other category) were assessed. The linear mixed-effect models indicated that the infants with PAIS had an estimated 10.8-point increase in total HINE scores after 9 months of age compared to earlier assessments (95% CI [2.5, 19.2]. There was no statistically significant improvement in the scores among the infants in the other brain injury groups. The infants with PAIS had an estimated 2.9-point increase in HINE asymmetry scores after 9 months of age compared to prior visits (95% CI [0.7, 5.1]). None of the other diagnostic categories had statistically significant increases in asymmetry scores over time. <b>Conclusions</b>: The children with PAIS with resultant hemiplegia showed increasing HINE scores throughout the first two years of life. In contrast, the HINE scores remained stable for those children with term HIE, prematurity-associated brain injury, and congenital malformations and/or congenital hydrocephalus diagnosed with CP. Tracking individual changes (or stability) in HINE scores can aid diagnosis, inform prognosis, and guide the design of clinical trials targeting neurologic injury.