Cognitive functioning in children after haemorrhagic stroke

Hemorrhagic stroke accounts for almost half of all childhood strokes and is associated with neurological impairment and poorer quality of life. Despite this, research examining cognitive outcomes after hemorrhagic stroke in children is lacking. While still under-researched, cognitive function after ischemic stroke has received relatively greater attention in recent years. Studies examining children with ischemic stroke have generally reported near normal mean IQ, but skewed towards the lower end of the average range and lower than control groups and standardized test norms. A small number of studies have also found deficits in higher level cognitive domains including attention, executive function, processing speed, and working memory. One study that examined long-term cognitive function in 31 children with hemorrhagic stroke reported 50% had cognitive impairment, while outcomes reported by other studies in this population have been limited to global neurological function, which fails to capture the subtlety of cognitive deficits. In the first study to measure cognitive function in children with intracerebral hemorrhagic stroke over time, Murphy et al. reported that while verbal comprehension and perceptual reasoning improved over a 2-year period, the same trajectory was not observed for processing speed and working memory. Processing speed scores were in the average range at 1 and 2 years’ post-stroke, but the interquartile ranges showed low performance. Raw scores for working memory showed improvement over time; however, age-normed percentiles showed these children did not progress to age expectations and their performance remained well below that of their peers at both 1 and 2 years’ post-stroke. Early brain injury research has shown that deficits may emerge or worsen with time as a child develops and cognitive demands increase. Children may fail to make age-appropriate developmental gains and appear to ‘grow into deficits’. Similar findings have been reported in a study of children with neonatal ischemic stroke. During preschool, cognitive performance did not differ to normative expectations. However, at school age, poorer performance was observed for Full-scale IQ, working memory, and processing speed. Like the findings reported in the study by Murphy et al., Westmacott et al. found that children’s raw scores improved, indicating no actual regression in cognitive skills but rather, declines in standardized scores reflecting slower gains over time as compared to same-age peers. Results for Murphy et al. suggest that after pediatric hemorrhagic stroke cognitive skills do not necessarily improve progressively over time. In fact, recovery patterns may vary, with some cognitive domains showing a decline. For example, studies examining general intellectual ability often document improvement to within the average range, while those assessing higher level cognitive skills, such as working memory and processing speed, describe lack of gains, reflecting greater vulnerability. Many of these complex cognitive skills are not easily observable in younger children and deficits may not be evident in routine early, clinical follow-up but gradually emerge over time as the child fails to meet developmental expectations. Interestingly, results from Murphy et al. indicate an improvement in children’s raw scores with time; so, while a child makes progress, they may not be making age-appropriate gains. These findings highlight the importance of monitoring children after hemorrhagic stroke and the need for comprehensive neuropsychological evaluation to assess change over time.