Child stroke survivors have time on their side

A baby just a week old is three times more likely to suffer a stroke than an adult who smokes and suffers from diabetes and hypertension.

That makes stroke one of the top 10 killers of children, and we don’t know why.

But we do know that the window for recovering motor skills following brain damage from a stroke is open wider for children than for adults, and research at the Murdoch Childrens Research Institute and the University of Melbourne is now finding out just how wide that window is.

The results so far are good news, suggesting that child-stroke victims keep recovering and benefitting from rehabilitation well after a stroke has hit, when for an adult the potential for recovery is concentrated in a narrow window of just three-to-six months. But that means children need more monitoring and long-term rehabilitation.

The longitudinal study of 64 Australian child stroke victims could for the first time provide worried parents and their health practitioners more certainty on the outlook for children recovering from stroke.

“What these results suggest is that children need an individualised approach to their care and rehabilitation, which is guided in part by their age at the time of the stroke, and they need to have their progress monitored in the long term by a multidisciplinary team,” says lead researcher, occupational therapist and PhD student Ms Anna Cooper.

The ongoing study, published in US journal Pediatrics, focused on children who had suffered acute ischemic stroke (AIS), which is when the blood supply to the brain is constrained by an artery blockage such as a blood clot. Strokes can also be caused by a ruptured blood vessel. The risk of AIS is about 1 in 4,000 for babies less than 30 days old, falling to 2-to-8 in every 100,000 in older children.

The researchers found that the children in the study were continuing to show signs of recovery 12 months on from the stroke.

For babies however the extent of any impairment was still emerging because before four months of age babies move largely by reflex. That means that any damage affecting motor skills may not be observable until they are older.

“Children are continuously developing and changing, and they are experiencing environmental and social changes in their lives that can all affect the trajectory of their recovery from stroke,” says Ms Cooper who is based at MCRI and the University of Melbourne, and works at the Royal Children’s Hospital.

The researchers are continuing to track the 64 children to further monitor their recovery trajectory and the factors that may influence it.

The children in the study, who had all been diagnosed with acute ischemic stroke, were recruited between December 2007 and November 2013. Of these, 27 were aged less than 30 days, a further 19 were preschoolers, and 18 were school-aged.

Ms Cooper says the study will help shed light on how well babies recover from stroke compared to older children. In many cases, older children face having to relearn various motor skills impaired by the stroke. However in babies these skills won’t have been learned before the stroke.

“A six year-old who suffers a stroke may have to be relearning how to walk, whereas a baby has to recover from an impairment that will affect their walking without knowing how to walk in the first place. So they may be having to learn from a compromised position.”

But alternatively being so young may help. Ms Cooper says there is debate over whether the greater “plasticity” of a baby’s brain, which makes it easier to adapt, may actually help them overcome a stroke impairment in learning motor skills compared to older children relearning those skills.

The results of the study so far suggest that preschoolers may have the best combination of plasticity and learned behaviour for recovery.

“They may be the age group where there is an optimal balance between greater brain plasticity and less vulnerability,” the researchers say in their paper.

Ms Coopers say she hopes the results will inform guidelines now being developed to better inform health practitioners and parents by giving them more idea of what sort of impairment they can expect to see in children as they grow, and what their trajectory for recovery is likely to be.

“At the moment, when a child has a stroke we can’t tell the parents what is going to happen in terms of motor function because it is really unclear. But with this research we hope to eventually be in a position to tell parents what they can anticipate,” says Ms Cooper.

“I think that will be really helpful and empowering for parents.”

Banner image: US Air Force photo/Staff Sgt Taylor L. Marr