Reference material for Hammersmith Infant Neurological Examination scores based on healthy, term infants aged 3 to 7 months

Abstract

Objective To provide a valid, continuous reference interval, including a 10 th percentile cut-off, for Hammersmith Infant Neurological Examination (HINE) scores based on 3-7 months old term infants with weight appropriate for gestational age. Study design In a prospective study we examined 168 Norwegian infants at one timepoint with HINE at 3-7 months of age. In 134 of these infants Ages and Stages Questionnaire was completed by their parents at two years of age to ensure typical motor development. We calculated a reference interval for HINE scores with the 10 th percentile as cut-off for age-dependent optimal scores. Results The best fitting mean model for HINE total score was 78.1358+9659.231*1/age 2 -5104.174*LN(age)/age 2 , which explained 49.8% of the variance. The HINE total score 10 th percentile cut-off corresponded to 52.1 points at age 12 weeks, 55.6 points at 16 weeks, 59.0 points at 20 weeks, 61.8 points at 24 weeks and 63.8 points at 28 weeks. We found an excellent intra-class correlation coefficient of 0.953 (0.931-0.968) between two examiners. The infants had a typical motor development at two years follow-up. Conclusion We have presented a valid, continuous reference interval and a 10 th percentile cut-off for HINE scores for infants aged 3 to 7 months.