For children who have experienced an arterial ischemic stroke, long-term outcomes are often uncertain. Recovery is believed to depend on stroke severity, timing of treatment and initiation of appropriate therapy. In a study published in the June issue of the Journal of Child Neurology, however, Christine Hajek, PhD, a postdoctoral researcher at Nationwide Children’s Hospital, and her colleagues determined that the outcomes of pediatric stroke could be more complex in origin than previously thought. In fact, lingering effects of stroke may impact future cognitive function like other pediatric chronic illnesses—even those that don’t directly involve the brain.
“Chronic illness itself may have effects on cognitive function that do not necessarily require a central nervous system insult. Our data suggest that lower cognitive scores among children with stroke are likely related to the combination of neurological impairment following stroke and the presence of chronic stroke-related illness,” says, Dr. Hajek, lead author of the study. “The outcome of pediatric stroke is more complex than previously recognized—it’s affected by a variety of factors.”
Unlike previous research on the topic, this study compared children with a prior arterial ischemic stroke to children with asthma. The study was the first to include a comparison group comprised of children with a chronic illness not affecting the central nervous system, a distinction that allowed the researchers to determine how stroke affects cognitive outcome compared to chronic illness in general.
The study enrolled 51 participants up to 14 years of age at both Nationwide Children’s and Royal Children’s Hospital in Melbourne, Australia. The team examined stroke lesion location and volume to determine whether these factors could predict cognitive outcomes following a stroke. Both groups of children then completed a series of pediatric cognitive performance tests to compare cognitive abilities.
The approach offered some new insights. “We expected both stroke severity and lesion volume to be related to cognitive outcome, but this was not always the case,” says Dr. Hajek. Greater stroke severity and lesion volume resulted in lower cognitive scores only in certain functional categories. Both study groups scored significantly lower on the cognitive tests than the normative population, but the stroke group scored only slightly lower overall than the asthma group.
These findings point to the need for more in-depth analysis of the effects of stroke on general cognitive outcome, social outcome, and verbal and nonverbal functioning, according to Dr. Hajek. The published study was part of a larger project in which she and her colleagues collected data to examine social and cognitive outcomes after stroke.
“Research examining outcomes following neurological insults, such as stroke, provides insight into how the developing brain functions and recovers after injury,” says Dr. Hajek. “We are interested to learn more about possible predictors and which factors lead to greater impairment.”
By gaining a better understanding of the biological mechanisms and predictive factors at play in the recovery process, it may be possible to improve the treatment and rehabilitation of these patients, Dr. Hajek notes. “In a clinical setting, assessment of clinical and neuropsychological functioning is imperative to determine which children are exhibiting stroke-related deficits and need accommodations at home or at school.”
Hajek CA, Yeates KO, Anderson V, Mackay M, Greenham M, Gomes A, Lo W. Cognitive outcomes following arterial ischemic stroke in infants and children. Journal of Child Neurology. 2013 Jun 11.
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