A systematic review of MRI studies of language development from birth to two years of age

Abstract

Volumetric brain growth in humans is most dramatic during the first two years of life. It is also the time when linguistic abilities develop at a rapid pace. Maturation of language skills requires the co-operation of multiple brain regions simultaneously. However, there is a lack of information about the timing of developmental changes among brain areas that are considered the most essential to early speech production and how these structural features correlate to cognitive performance. In this review, we collected language-related child magnetic resonance imaging studies carried out with healthy normally developing infants from birth to 2 years of age from 2012 onwards. 11 articles were identified for the final review. Cortical language related areas of the brain include frontal and temporal regions. Many studies implicate a volumetric leftward asymmetry of the brain as a determinant of language skills, yet with marked variance in the available studies. Temporal and frontal region volumes had positive correlations to cognitive test scores. The maturation of language related white matter pathways seemed to correlate positively to cognitive test scores, but there was no consensus among the reviewed papers. The review highlights that the number of MRI studies of language development in the first 2 years of life is relatively small, with variable number of participants. Small sample size and cross-sectional study design limit the conclusions. Future studies would benefit from a longitudinal design, multimodal imaging approach and larger sample sizes to form a more complete picture of the development of structural language-related brain regions.