New Zealand Leads the Way in Identifying Brain Damage in Premature Babies
New Zealand researchers have gained international recognition for a study that uses Magnetic Resonance Imaging (MRI) to
detect brain injury in very preterm infants.
The team’s findings will be published next week in the prestigious New England Journal of Medicine by Canterbury
researchers Associate Professor Lianne Woodward (University of Canterbury), Dr Nicola Austin (Christchurch Women’s
Hospital), New Zealander Associate Professor Terrie Inder (St Louis Children’s Hospital) and colleagues from Australia.
Dr Inder was also the recipient of the Neurological Foundation’s Senior Clinical Fellowship in 1998 and continued her
work in Australia and now the USA.
Using MRI to monitor the brain development of babies born prematurely will improve the early identification of children
at risk of serious neurodevelopmental problems such as cerebral palsy, severe cognitive delay, vision and hearing
problems.
The project, co-funded by the Neurological Foundation, highlighted that New Zealand neurological research was at a
world-class level, said Neurological Foundation director Max Ritchie.
“To be published in what is considered the world’s leading medical journal is recognition of the considerable talent and
hard work the research team has put in on this study,” he said.
The study involved tracking the development from birth to age two years of 167 babies born very premature (30 weeks or
less) at either Christchurch Women’s Hospital in New Zealand or the Royal Women’s Hospital in Melbourne, Australia. As
part of the study, detailed information was collected about each infant’s neonatal course, with all infants undergoing
an MRI scan at 40 weeks gestation, the age at which most infants would typically be born. At age two years, 96% of the
infants were re-contacted and assessed by a team of developmental and medical specialists for a range of serious
neurodevelopmental problems, including cerebral palsy, severe cognitive delay, severe psychomotor delay, vision and
hearing impairment.
The study compared the clinical usefulness of abnormal findings on an MRI scan, particularly in the white matter or
cabling networks of the brain, with other measures that are currently used, including gestational age at birth,
ultrasound abnormalities and measures of infant health during their hospital stay. The results of their study showed
that MRI was superior to all other measures in predicting outcome.
Dr Woodward said that the study’s findings from this large Australasian sample confirmed the high rates of
neurodevelopmental impairment found in other follow up studies of children born very preterm relative to term born
children
By age two years (corrected for gestational age at birth), 17 percent of infants showed severe cognitive delay, 10
percent showed severe psychomotor delay, 10 per cent had cerebral palsy and 11 percent had clinically significant visual
or hearing impairments.
“Having a premature baby can be an extremely stressful and worrying time for parents, with questions about their child’s
future often being at the forefront of their minds. It is important that we be able to help them plan for their child’s
and family’s future, as well as identifying as accurately as possible, those children who are at greatest risk. This is
essential if we are to ensure they get the help and support they need.”
Dr Austin, Clinical Director of the Neonatal Unit at Christchurch Women’s Hospital said that predicting the future after
premature birth is difficult based on clinical parameters alone. We know that extremely premature babies (<28 weeks) have a higher incidence of later problems, but only a few other factors such as postnatal steroid use and
severe abnormality on ultrasound appear to be clinically significant long term. Fortunately only a small number of our
babies have either of these factors. What this follow-up study tells us is that if a baby’s MRI scan is normal we can be
confident in reassuring parents that their child’s outcome will be good. However, if a baby’s MRI scan shows clear signs
of abnormality then we, can with a high degree of confidence say that this child ought to be at least monitored
following hospital discharge or be referred to early intervention.”
However Dr Woodward, said it was important to note that although more than half of the children with moderate to severe
white matter abnormalities on their neonatal MRI scan showed some form of severe neurodevelopmental limitation by 2
years of age, a number of these children were also doing quite well.
“This finding is promising and really reiterates what we already know in terms of children’s development. That is, that
development is influenced by a large number of factors of which early brain development whilst clearly important, is but
one. Other factors such as the quality of parenting, early attachment relationships, the home environment, and the
availability of educational support when needed, will also be important in determining these children’s futures, just as
with all children.”
“Two years of age is also very early to be making strong statements about a child’s development so continued monitoring
of our study children’s development is a high priority. This is also important given that we know from previous studies
that many of the problems faced by very premature children, including learning and behavioural difficulties, only become
more obvious when children are confronted by the performance and behavioural demands of the education system.
“Whilst these results are promising in terms of the early detection of high risk premature children, this is only one
piece of an important puzzle. Now that we can identify these children, we need to develop research based strategies to
help them and their families in early childhood and at school.”
ENDS