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Brain injury and its consequences in extremely premature babies. John Wyatt Perinatal Brain Protection and Repair Group University College London. Survival of babies 23-25 weeks gestation UCLH 1981-2000 (as percentage of admissions to NICU). Riley et al. Acta Paediatrica 2008; 97:159-65.
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Brain injury and its consequences in extremely premature babies John Wyatt Perinatal Brain Protection and Repair Group University College London
Survival of babies 23-25 weeks gestation UCLH 1981-2000 (as percentage of admissions to NICU) Riley et al. Acta Paediatrica 2008; 97:159-65
Percentage of surviving extremely preterm infants with neurodevelopmental impairment at 1 year of age, UCLH 1981-2000 Riley et al. Acta Paediatrica 2008; 97:159-65
Neurodevelopmental outcome at 8 years of age < 28 weeks 28 – 32 weeks (n = 137) (n = 445) Disability 23% 12% Brain lesion detected 48% 22% by ultrasound Vollmer et al, Pediatrics 2003, 112, 1108-1114
EPICURE nationwide study of all babies in UK and Ireland, born 22-25 weeks gestation in 1995. Assessment at 6 years of age Out of 241 survivors: • 15 were unable to walk due to cerebral palsy • 27 had severe learning difficulties • 4 blind and 7 severe hearing loss • Total of 32 had any severe disability Marlow et al. NEJM 2005; 325: 9-19
Cognitive (IQ) scores for ex-premature infants at 6 years of age compared with class mates
Rate of cortical development is maximal between 22 weeks and term
Rate of synaptic development • ~ 1011 neurons in CNS • Each neuron develops ~ 103 synapses • Therefore total of ~ 1014 synapses created – majority are formed between 22 and 40 weeks of gestation = ~ 5 x 1011 synapses per day =~ 3 x 108 synapses per minute!
Cranial MRI scans at 14 years in a cohort of ex-preterm infants MRIEx-preterm Term controls Normal 23% 71% Equivocal 21% 24% Abnormal 56% 5% Stewart et al, Lancet 1999, 353: 1653-1657
MRI abnormalities in ex-preterm adolescents at 14 years • MRI abnormalities correlated with abnormal behaviour scores. • MRI abnormalities did not correlate with IQ, with neurological signs or with need for extra educational help.
Grey matter changes in ex-preterm adolescents Nosarti et al, Brain 2002, 125, 1616-1623
White matter changes in ex-preterm adolescents Nosarti et al, Brain 2002, 125, 1616-1623
Changed brain microstructure following developmental care programme Als et al. Pediatrics 2004, 113, 846-857
Possible mechanisms of improved outcome following perinatal brain injury • Cell differentiation and replacement from neuronal and glial precursor stem cells • Refinement and selection of dendritic synaptic connections • Rerouting of white matter connections • Development of alternative cortical processing strategies
Conclusions • White matter injury in extremely premature infants is the most important cause of long term neurodevelopmental disability. • The developing central nervous system has remarkable potential for repair and compensation following perinatal injury • New therapeutic approaches are required to translate experimental findings into practical therapies whilst babies are undergoing intensive care and following discharge from hospital
Centre for Perinatal Brain Protection & Repair Obstetrics & Gynaecology, Paediatrics & Child HealthMedical Physics & Bioengineering UCL NHS Trust Chiara Nosarti Fran O'Brien Claire Price Larry Rifkin Kate Riley Nikki Robertson Maeve Rooney Simon Roth Teresa Rushe Al Santhouse Alison Skinner Faraneh Vargha-Khadem Brigitte Vollmer Acknowledgements Ann Stewart Osmund Reynolds Matt Allin Topun Austin Jenny Baudin Alan Connolly David Edwards Michelle de Haan Angela Huertas-Ceballos David Gadian Robin Murray Brian Neville