Motor Performance at 18 Months and 6-8 Years in Cooled Survivors Without Cerebral Palsy following Perinatal Asphyxial Encephalopathy

Background: Even in the absence of cerebral palsy (CP), we found significantly lower total MABC-2 scores in children cooled for perinatal asphyxial encephalopathy (PAE) compared to age matched controls at 6-8 years (1). The Bayley Scales of Infant Development 3rd Ed (Bayley-3), commonly used at 18-24 months, yield higher than expected Motor Composite (MC) scores (2) and may not predict later motor performance. Furthermore, the relationship between early school age motor and cognitive function in cooled children without CP, is unknown. We hypothesised that motor performance at 18-24 months would predict motor performance at 6-8 years. Methods: We assessed 28 (20 male), 6-8 year old children without CP, all cooled for PAE using MABC-2 and the WISC-IV. All children had been evaluated at 18 months using the Bayley-3. We calculated the proportion of children with Bayley-3 MC scores <70 and <85 as predictors of motor impairment (MABC-2 <15th/5th centile). Baseline characteristics, Bayley scores at 18 months and WISC-IV scores at 6-8 years for the children with MABC-2 scores > and <15th centile were compared. Results: Median(range) MABC-2 total standard score for the 28 children was 8(1-15). Ten (36%) had MABC-2 total scores <15th centile, including 7(25%) <5th centile. There were no significant differences in clinical characteristics at birth between those children with MABC-2 scores > or < 15th centile. All children with low MABC-2 scores < 15th centile had Bayley-3 MC scores >70 at 18 months and all but one >85. WISC-IV total scores, perceptual reasoning and working memory subscale scores were significantly lower in children with MABC-2 scores <15th centile compared to those >15th centile. Bayley-3 Language, but not Bayley-3 Cognitive composite scores at 18 months, were also significantly lower in children with MABC-2 scores <15 centile at 6 to 8 years. Conclusion: Over a third of children without CP following PAE treated with cooling had some motor impairment at early school age, which was not adequately identified by motor assessment using Bayley-3 at 18 months. Motor impairment in cooled children was associated with language delay at 18 months and difficulties with perceptual reasoning and working memory at early school age. Further investigation of these co-existing deficits and other factors that may influence motor performance at school age in such cohorts is indicated.