Introduction: In term infants, therapeutic hypothermia for hypoxic-ischaemic encephalopathy (TH-HIE treatment) can improve and prevent dyskinetic cerebral palsy (CP). Dyskinetic CP can be assessed by the phenotype and also by the Dyskinesia Impairment Scale (DIS; i.e. the summed score for dystonia (DIS-D) and choreoathetosis (DIS-C)(1)), which is interpretable against the age-related values in healthy children.(2) In a cohort of (pre)school children, who had previously received TH-HIE treatment, the association between phenotypic and quantitative assessment is still unknown.

Methods: From an eligible group of previously treated TH-HIE children (UMCG; 2009-2012), we included all (pre)school children that consented to participate (n=21). Three paediatric neurologists and seven investigators provided phenotypic and quantitative assessment (DIS), respectively. We associated motor phenotype with quantitative DIS scores and also with parental reports about the child's global cognitive functioning.

Results: Phenotypic motor outcomes were: normal (n=18), mildly abnormal (n=2; i.e. discretely ataxic) and abnormal (n=1; cerebral palsy (CP) with spasticity and dystonia). The normal and mildly abnormal phenotypic subgroups revealed similar DIS scores, which were lower than dyskinetic CP scores (mean difference: 65 points; p<0.05)(1) and higher than in healthy, age-matched control children (mean difference: 19 points; p<0.05)(2). The child with CP revealed pathological DIS scores and impaired cognitive functioning, demanding a special school.

Conclusion: In (pre)school children with relatively favourable TH-HIE treatment outcomes, DIS scores are generally interpretable as non-pathologic, but still higher than in age-matched controls. Future studies may indicate whether these potentially "sub-optimal" DIS scores could suggest subtle neurological abnormalities later in life.

References:

1. Monbaliu E, Ortibus E, De Cat J, et al. The Dyskinesia Impairment Scale: a new instrument to measure dystonia and choreoathetosis in dyskinetic cerebral palsy. Dev Med Child Neurol. 2012;54(3):278-283

2. Kuiper M, Brandsma R, Vrijenhoek L, et al. Physiological Movement Disorder-like Features during typical motor development. Eur J Paediatr Neurol. 2018;22(4):595-601.