Cognitive outcome following unilateral arterial ischaemic stroke in childhood: effects of age at stroke and lesion location.
OBJECTIVE
Plasticity in the developing brain is a controversial issue. Although language and motor function often recover remarkably well following early brain injury, recent evidence suggests that damage to the developing brain results in significant long-term neuropsychological impairment. Our aim was to investigate the relationship among age at injury, lesion location and intellectual outcome.


METHODS
Using age-appropriate Wechsler scales of intellectual ability, we explored this issue by evaluating a large group (n=145) of children (89 males, 56 females) who experienced unilateral arterial ischaemic stroke during the perinatal period (diagnosed mean 73d, SD 29d), between the ages of 1 month and 5 years (mean 2y 10mo, SD 1y 9mo), or between the ages of 6 and 16 years (mean 11y 1mo SD 3y 6mo). The mean age at assessment was 8 years (SD 3y 10mo) in the perinatal group, 7 years 5 months (SD 2y 9mo) in the 1 month to 5 years group, and 12 years 5 months (SD 3y 9mo) in the 6 to 16 years group. The mean time interval between stroke and assessment was 8 years (SD 18d) for perinatal, 4 years 6 months (SD 1y 5mo) for 1 month to 5 years, and 1 year 4 months (SD 2y 9mo) for 6 to 16 years. The relationship between age at stroke and lesion location (subcortical, cortical, or combined) as it pertains to cognitive outcome was also examined.


RESULTS
Measures of overall intelligence, verbal ability, working memory, and processing speed were significantly lower in children who had had a stroke than in the normative sample (all z>2.5, all p<0.01). The perinatal group performed more poorly than the other two groups on most cognitive measures, regardless of lesion location. The combined lesion location group performed more poorly than those with damage to either cortical or subcortical areas alone. Further investigation revealed different periods of peak vulnerability for subcortical lesions (perinatal) and cortical lesions (1mo-5y).


CONCLUSIONS
Lesion location modulates the relationship between age at stroke and cognitive outcome.
Westmacott
Robyn
R
Department of Pediatrics, Hospital for Sick Children, University of Toronto, ON, Canada. robyn.westmacott@sickkids.ca <robyn.westmacott@sickkids.ca>
Askalan
Rand
R
MacGregor
Daune
D
Anderson
Peter
P
Deveber
Gabrielle
G
D000293:Adolescent; D017668:Age of Onset; D001157:Arterial Occlusive Diseases / Q000150:complications; D001921:Brain / Q000473:pathology*; D002648:Child; D002675:Child, Preschool; D003072:Cognition Disorders / Q000175:diagnosis / Q000209:etiology*; D005260:Female; D005500:Follow-Up Studies; D007839:Functional Laterality; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007360:Intelligence / Q000502:physiology; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008570:Memory, Short-Term / Q000502:physiology; D015999:Multivariate Analysis; D009483:Neuropsychological Tests; D012727:Sex Characteristics; D013223:Statistics as Topic; D020521:Stroke / Q000150:complications* / Q000209:etiology / Q000473:pathology*; D015898:Tomography Scanners, X-Ray Computed; D014705:Verbal Behavior / Q000502:physiology