A systematic review of MRI studies of language development from birth to 2 years of age

Neurocognitive functions supporting language development start to develop well before first words are spoken during the first years of life. This process coincides with the initial growth spurt of the brain. While the core components of the language network are well characterized in adults and children, the initial neural correlates of language skills are still relatively unknown. We reviewed 10 studies identified via a systematic search that combined magnetic resonance imaging and language-related measures in healthy infants from birth to 2 years of age. We aimed to describe the current knowledge as well as point out viable future directions for similar studies. Expectedly, the implicated cerebral areas included many established components of the language networks, including frontal and temporal regions. A volumetric leftward asymmetry of the brain was suggested as a determinant of language skills, yet with marked interindividual variation. Overall, temporal and frontal brain volumes associated positively with language skills. Positive associations were described between the maturation of language related white matter tracts and language skills. The language networks showed adult-like structural similarities already in neonates, with weaker asymmetry compared to adults. In summary, we found some evidence that the language circuit described in older age groups is also associated to language skills during the first 2 years of life. However, across the reviewed studies there were no systematic neural correlates of language skills, which is partly explained by a modest number of studies, scattered representation of ages in measurements and the variance in the used methods.

Automated summary

The neurocognitive functions supporting language development start to develop well before first words are spoken during the first years of life. While the core components of the language network are well characterized in adults and children, the initial neural correlates of language skills are still relatively unknown. Studies combining magnetic resonance imaging and language-related measures in healthy infants from birth to 2 years of age have shown that volumetric leftward asymmetry of the brain, temporal and frontal brain volumes, and maturation of language related white matter tracts are all positively associated with language skills. However, there is a lack of systematic neural correlates of language skills due to a modest number of studies, scattered representation of ages in measurements and the variance in the used methods.