1. Can birth asphyxia result in learning difficulties without cerebral palsy?
Ben Lloyd
Consultant Paediatrician
Royal Free Hospital, London
AvMA 19th September 2007
Ben Lloyd
Consultant paediatrician

2. Seamus

3. Timetable Definitions of birth asphyxia + cerebral palsy
Criteria to be met to link birth asphyxia + cerebral palsy
Current consensus about impairments after birth asphyxia
Evidence to challenge this consensus
Summary of my view of the current situation

4. What is birth asphyxia
Impaired placental gas exchange causing hypoxia (low oxygen level), high carbon dioxide levels and acidosis
Hypoxia and acidosis cause impaired cardiac function which causes impaired brain circulation (ischaemia)

5. What is cerebral palsy
A motor impairment due to a non progressive lesion in the developing brain
Not necessary to have any learning difficulties - but usually have some

6. Necessary criteria to link cerebral palsy to birth asphyxia
No antenatal cause
No postnatal cause
Evidence of fetal distress
Poor condition at birth
Metabolic acidosis at birth
Encephalopathy in first hrs/days of life
Four limb cerebral palsy
Characteristic MR changes

7. John Severe dyskinetic cerebral palsy No antenatal or postnatal damage
Terminal bradycardia because of abruption
Severe encephalopathy
By 12 months diagnosed as dyskinetic cerebral palsy
MR scan - characteristic changes following acute, near total hypoxic-ischaemic insult

8. Christine No antenatal or postnatal damage
Some fetal distress due to prostin - disputed how much fetal distress
Apgars 7 & 9 - no active resuscitation
Moderate and prolonged encephalopathy
Cerebral palsy - considered to be hemiplegia

9. Christine - part 2
Asymmetrical quadriplegia (4 limbs involved) - not hemiplegia (arm + leg on same side)
MR - showed asymmetric watershed damage
Good condition at birth due to autoresuscitation

10. One lesson from Christine’s case
Clinical features can be misleading.
MR scan often crucial in establishing causation

11. Annie Water birth - significant fetal distress
Poor condition at birth. Acidosis
Significant encephalopathy
Normal development at 10 months
Two and a half years old - delayed speech but normal motor development

12. Annie - part 2 MR scan showed extensive watershed damage
Annie’s learning difficulties can be confidently attributed to birth asphyxia

13. One lesson from Annie’s case
The MR scan can show asphyxial damage in children who have no cerebral palsy

14. Current consensus in relation to learning difficulties and asphyxia
“It is feasible to apply an asphyxial cause to this small group of children only if the relevant perinatal criteria are met and if there is evidence of hypoxic-ischaemic damage to the brain on imaging”
Lewis Rosenbloom - Clinical Risk 1996

15. Professor Charlene Robertson’s work
Has written papers from the 1980s onwards showing that learning difficulties are common after birth asphyxia
Papers not very clear about how many of these children did not have cerebral palsy and about how many had undergone CT or MR scanning

16. Summary of Prof Robertson’s findings
Studied 407 children with moderate HIE who did not have cerebral palsy
40 of the 407 (10%) had DQ/IQ of less than 70 - significant cognitive impairment - versus 2.3% background rate
Very little scanning evidence

17. What Professor Robertson’s work contributes
Learning difficulties (without cerebral palsy) are common after birth asphyxia and encephalopathy - about 10%
BUT no evidence to challenge Lewis Rosenbloom’s assertion that in such cases there must be an abnormal MR scan in order to establish causation

18. What is needed to overturn current consensus
Large follow up study of survivors of asphyxia and encephalopathy
Needs to be to at least school age
Needs to include MR scans

19. A paper from Hammersmith Hospital
68 asphyxiated babies. 15 died. 19 had cerebral palsy. 34 others - studied, at age around 5-6.
3 children with IQ under 80.
1 child (IQ 76) had normal MR scan

20. Conclusions from Hammersmith Hospital paper
Small study - just 34 children
Children young - school performance may worsen
Evidence could be used to either support or challenge the current consensus

21. Two papers from Sweden
Starting cohort - all 684 Swedish babies with apgar of less than seven in 1985
56 of these developed encephalopathy; 43 agreed to be studied.
15 had cerebral palsy; so 28 in study

22. Swedish study - part 2
All 28 interviewed on phone; 11 had IQ testing; 8 had MR scans
5/28 had IQ less than 70
In all, 11/28 had mild learning disability or borderline intelligence vs 2/15 sibling controls

23. MR findings in Swedish study
Eight underwent MR scans - not clear who did and who did not undergo MR
Three had periventricular leucomalacia
One had watershed damage

24. Diffusion Tensor Imaging Nagy and coworkers
8 survivors of moderate HIE without CP
3 had IQ<70; 3 had IQ >70 but <85
4 had normal conventional MR scan
DTI (specific for white matter damage) showed abnormalities in all 8 - controls had fewer abnormalities

25. Conclusions from Swedish studies
Learning difficulties with no cerebral palsy are common after birth asphyxia
At least some children with learning difficulties probably had normal conventional MR scans
Many/most/all children with normal conventional MR scans had abnormal findings on diffusion tensor imaging

26. Quantitative MR studies Gadian and coworkers
Five babies suffered severe hypoxia-ischaemia
All now have severe memory problems
No cerebral palsy
Conventional MR normal
Quantitative MR studies showed severe hippocampal atrophy in all cases
Brain 2000:123;

27. My own experience - part 1
I have reviewed 350+ cases in which birth asphyxia has been queried as a cause of a child’s impairments
In just over 100 of these cases were the impairments caused by asphyxia

28. My own experience - part 2
12 children with learning difficulties and no cerebral palsy following birth asphyxia+ encephalopathy
All had negative family histories

29. My own experience part 3
Of the 12 children with learning difficulties and no cerebral palsy:
2 had obvious asphyxial damage on MR
6 had normal MR scans
4 have not undergone an MR scan

30. How many normal MR scans would you expect if Lewis Rosenbloom is right?
Robertson reported that 9.8 % of survivors had an IQ<70 vs 2.3% expected in general population
Thus, would expect some to have normal MR scans - because the asphyxia was coincidental
If Lewis Rosenbloom is right then would expect ratio of abnormal to normal scans to be 9.8:2.3 - ie 4.3:1

31. My own experience
If Lewis Rosenbloom is right (and Prof Robertson’s numbers are right) one would expect ratio of abnormal to normal MR scans of children with learning difficulties after birth asphyxia to be 4.3:1 - ie most would have abnormal scans
In my very small series (but larger than any published series of children with LDs after asphyxia/encephalopathy) of eight children the ratio is 2:6 - ie most had a normal scan

32. Quantitative MR studies Gadian and coworkers
Five babies suffered severe hypoxia-ischaemia
All now have severe memory problems
No cerebral palsy
Conventional MR probably normal
Quantitative MR studies showed severe hippocampal atrophy in all cases
Brain 2000:123;

33. Diffusion Tensor Imaging Nagy and coworkers
9 survivors of moderate HIE without CP
3 had IQ<70; 3 had IQ >70 but <85
4 had normal conventional MR scan
DTI (specific for white matter damage) showed abnormalities in all 9 - controls had fewer abnormalities

34. Role for specialised MR
Diffusion Tensor Imaging - not yet available. Needs more research before could cite in Court.
Quantitative examination of the hippocampus - is available in UK. Consider for children with memory problems

35. Seamus Severe acute near total asphyxia due to shoulder dystocia
No heart beat for seven minutes
Very severe encephalopathy
“Normal” at 18 months - according to professor of developmental paediatrics
Age six - learning difficulties and clumsiness

36. Seamus - part 2
Age 17 significant learning difficulties - particularly memory.
Normal size head
No motor deficit
Intelligent parents
Normal MR scan. I advised further study.

37. Seamus part 3
Quantitative study of hippocampus undertaken by Professor Gadian’s team
Significant hippocampal atrophy found
Seamus’s impairments likely to be caused by substandard obstetric care

38. The next few years
More studies of survivors of asphyxia + encephalopathy with MR results will be published
DTI and other newer MR techniques will become available
I consider consensus will shift

39. Questions?

40. Summary - 1
Most babies whose brain is damaged by birth asphyxia will have frank cerebral palsy and an abnormal MR scan
Some babies whose brain was damaged by birth asphyxia will have learning difficulties but no cerebral palsy. Some/many will have an abnormal conventional MR scan

41. Summary - 2
If clinical features (perinatal + family history) are supportive, then a child with learning difficulties but no cerebral palsy should undergo a conventional MR scan
If conventional MR scan normal and poor memory consider quantitative study of hippocampi via Professor Gadian
Consensus likely to change in next few years Just wait.