Neuroimaging of decoding and language comprehension in young very low birth weight (VLBW) adolescents: Indications for compensatory mechanisms

Description: Objective Reading problems are more common in individuals born preterm with very low birth weight (VLBW ≤ 1500 g) than in normal birth weight (NBW) term-born peers. We investigated components of reading comprehension in young VLBW adolescents in direct comparison to NBW and measured neural activation within brain regions important for language with the use of functional magnetic resonance imaging (fMRI). We hypothesized that the decoding mechanisms will be affected by VLBW, and expect to see increased neural activity for VLBW which may be modulated by performance and cognitive ability. Methods 13 (11 included in fMRI) young adolescents (ages 12 to 14 years) born preterm with VLBW and in 13 NBW controls (ages 12 to 14 years) were investigated for performance on the Block Design and Vocabulary subtests of the Wechsler Intelligence Scale for Children; and for semantic, orthographic, and phonological processing during an fMRI paradigm. Results The VLBW group showed increased phonological activation in left inferior frontal gyrus, decreased orthographic activation in right supramarginal gyrus, and decreased semantic activation in left inferior frontal gyrus. Block Design was related to altered right-hemispheric activation, and left angular gyrus showed activation increase specific for VLBW with high accuracy on the semantic test. VLBW also showed lower scores on the WISC Block Design test. Conclusions Young VLBW adolescents showed phonological activation increase and semantic activation decrease in left inferior frontal gyrus, however not in overlapping cluster. The increase of activation for phonological decoding and lower Block Design is consistent with our hypothesis for an altered functionality of the phonological processing pathway in relation to impaired cognitive functioning. The results may reflect compensatory mechanisms by recruiting additional brain regions upon altered neural development of phonological decoding for VLBW; also the involvement of left angular gyrus was related to more successful semantic processing for VLBW.

Related article: http://doi.org/10.1371/journal.pone.0185571