Presented at the Neonatal Society 2013 Spring Meeting.
Northam GB1,2, Chong WK2, Adler S1, Rathbone R3,4, Cowan FM3,4, Baldeweg T1,2
1 UCL Institute of Child Health, London, UK
2 Great Ormond Street Hospital, London, UK
3 Imperial College London, London, UK
4 Imperial College Health Care Trust, London, UK
Background: Children with perinatally-acquired focal hemispheric lesions develop normal everyday language, even when lesions are large and encroach on left hemisphere language areas. This may be due to the capacity of the developing brain to compensate by functional reorganisation. However, as language abilities have not been fully characterised in this group (i.e. with formal testing) it is unclear whether subtle deficits persist. We predicted that language scores would be: (i) reduced in children with left hemisphere injury; (ii) associated with injury to perisylvian tissue (including the arcuate fasciculus); and (iii) that this relationship would be modified by reorganisation of language functions to the contralateral hemisphere.
Methods: Two groups were studied: (1) term-born children with perinatal ischaemic or haemorrhagic stroke (n=30, mean age 13.1yrs, 18 males): all were followed longitudinally and had neonatal neuroimaging (many were included in Ricci et al. 2008) and (2) control children, group-matched for parental education, age and sex (n=44). Neuropsychological evaluation of speech, language and intelligence (IQ) was performed together with detailed neuroimaging, including fMRI (to determine language dominance), DWI and volumetric T1-W imaging. Side of lesion was: Left =22, Right=7, Bilateral (L>R)=1. Ethical approval was given by the Institute of Child Health REC and funding was obtained from Action Medical Research UK.
Results: Children with a history of perinatal stroke had IQ scores within the average range (mean 99±14) but 13 points lower than controls. There was no significant change in verbal or performance IQ scores between age 6 and 13 years (current study). Language performance (CELF-3UK scores) was reduced after correcting for non-verbal IQ in children with left-sided injury only. Reorganisation of language functions to Broca’s homologue in the right hemisphere was observed in 44% of children with left-sided lesions. Unexpectedly, neither language scores nor atypical language lateralisation was related to the integrity of the left arcuate fasciculus. Rather, interhemispheric reorganisation was associated with lesions predominantly affecting the extreme capsule/uncinate fasciculus in the left hemisphere. Importantly, there was no difference in language abilities in children with typical (left hemisphere) language dominance versus those with atypical (right) representation.
Conclusion: Children with hemispheric lesions acquired in the perinatal period have language and IQ scores in the average range, but performance is nevertheless significantly lower than controls. Importantly, language ability is not related to lesion location, even when left hemisphere language areas are involved; this is possibly due to compensatory interhemispheric reorganisation in the developing brain.
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Ricci D, Mercuri E, Barnett A, Rathbone R, Cota F, Haataja L, Rutherford M, Dubowitz L, Cowan F. Cognitive outcome at early school age in term-born children with perinatally acquired middle cerebral artery territory infarction. Stroke. 2008 Feb;39(2):403-10.