Background: Acquisition of language during development is imperative for lifelong functioning. Perinatal stroke is an ideal human model of developmental neuroplasticity. Many children with perinatal stroke (arterial ischemic stroke [AIS] or periventricular venous infarction [PVI]) have intact language function despite damage to language areas. We examined the strength of functional connectivity of language networks in children with perinatal stroke.
Methods: Participants were recruited from a population-based perinatal stroke cohort and compared to right-handed typically developing controls (TDC). All were scanned at rest using a 3T GE MRI (36 slices, 3.6mm isotropic, repetition/echo time=2000/30ms, 150 volumes, ~6:00). Language networks were identified using a seed based technique measuring blood oxygen level dependent responses in bilateral inferior frontal gyrus (IFG) and posterior superior temporal gyrus (pSTG). Seed-to-seed temporal correlations quantified connectivity. Standardized language outcomes for a subset included measures of vocabulary (WISC-IV Vocabulary) and fluency (NEPSY-II Word Generation Initial Letter).
Results: The population was 68 children aged 6-19 (17 AIS [mean age 14.0±4.1], 15 PVI [12.8±4.0], 36 TDC [12.9±3.6]). Seven of 13 stroke children (54%) scored below the 10th percentile on the word generation task. TDC showed stronger interhemispheric connectivity between frontal (LIFG-RIFG r=0.82±0.3) and temporal (LpSTG-RpSTG r=0.79±0.2) areas compared to intrahemispheric (LIFG-LpSTG r=0.46±0.2; RIFG-RpSTG r=0.39±0.3). For AIS, interhemispheric connectivity between left and right IFG was lower than TDC regardless of stroke side [p<0.001]. For AIS with a left lesion, intrahemispheric connectivity in the right hemisphere appeared higher than TDC [p=0.051]. Connectivity for PVI participants was comparable to TDC. Neither intra- nor interhemispheric connectivity appeared to relate to language function in this simple network.
Conclusions: Functional strength of language networks is altered after AIS but not PVI. Connectivity of larger language networks needs further investigation to explore compensatory mechanisms and may help target language rehabilitation.