On the Biological Foundations of Language: Recent Advances in Language Acquisition, Deterioration, and Neuroscience Begin to Converge

In this paper, experimental results on the study of language loss in pro- dromal Alzheimer’s disease (AD) in the elderly are linked to experimen- tal results from the study of language acquisition in the child, via a tran- sitional stage of Mild Cognitive Impairment (MCI). Recent brain imag- ing results from a pilot study comparing prodromal AD and normal ag- ing are reported. Both, behavioral results and their underlying neural underpinnings, identify the source of language deficits in MCI as break- down in syntax–semantics integration. These results are linked to inde- pendent discoveries regarding the ontogeny of language in the child and their neural foundations. It is suggested that these convergent results ad- vance our understanding of the true nature of maturational processes in language, allowing us to reconsider a “regression hypothesis” (e.g., Ribot 1881), wherein later acquisition predicts earliest dissolution.