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 prodromal Alzheimer's disease (AD) in the elderly are linked to experimental results from the study of language acquisition in the child, via a transitional stage of Mild Cognitive Impairment (MCI). Recent brain imaging results from a pilot study comparing prodromal AD and normal aging are reported. Both, behavioral results and their underlying neural underpinnings, identify the source of language deficits in MCI as breakdown in syntax-semantics integration. These results are linked to independent discoveries regarding the ontogeny of language in the child and their neural foundations. It is suggested that these convergent results advance 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.