Neural origins of childhood apraxia of speech: state-of-the-art, future directions, and implications for models of speech motor control

<p>In the last several decades a series of neuroimaging and neurophysiological studies have aimed toidentify neuroanatomical sites and networks that may be responsible for the speech problems ofchildren with childhood apraxia of speech (CAS), a disorder that has long been viewed as havinga central (neurological) origin involving brain motor mechanisms responsible for planning andprogramming sequences of speech sound movements. The aim of this narrative review was toassess the results of this body of literature in order to gauge the current state of our knowledgeconcerning the brain structures and mechanisms that may be responsible for the core praxicfeatures of CAS. Our review indicates that the existing neuroimaging database shows littleconvergence across studies, in terms of the statistically significant anomalies reported byindividual studies, the regional or network anomalies emphasized in the conclusions sections ofindividual studies; and the reported hemispheric lateralization of anomalous brain regions ornetworks. We discuss the likely sources of this heterogeneity, consider possible interpretations,and point to future research directions guided by recent advances in our understanding of speechneuromotor control.</p>