Neurobiological bases of reading disorder part II: The importance of developmental considerations in typical and atypical reading.

Black, Jessica M.; Xia, Zhichao; Hoeft, Fumiko

Decoding-based reading disorder (RD; aka developmental dyslexia) is one of the most common neurodevelopmental disorders, affecting approximately 5-10% of school-aged children across languages. Even though neuroimaging studies suggest an impairment of the left reading network in RD, the onset of this deficit and its developmental course, which may include constancy and change, are largely unknown. There is now growing evidence that the recruitment of brain networks underlying perceptual, cognitive, and linguistic processes relevant to reading acquisition varies with age. These age-dependent changes may in turn impact the neurocognitive characteristics of RD observed at specific developmental stages. Here, we synthesize findings from functional and structural magnetic resonance imaging studies to increase our understanding of the developmental time course of the neural bases underlying (a)typical reading. We first provide an overview of the brain bases of typical and atypical (impaired) reading. Next, we describe how the understanding of RD can be deepened through scientific attention to age effects, for example, by integrating findings from cross-sectional studies of RD at various ages. Finally, we accent findings from extant longitudinal studies that directly examined developmental reading trajectories beginning in the preliterate stage at both group and individual levels. Although science is at the very early stage of understanding developmental aspects of neural deficits in RD, evidence to date characterizes RD by atypical brain maturation. We contend that exploring the developmental trajectories of RD will contribute to a greater understanding of how neural systems support reading acquisition. Further, we propose and cite evidence that the etiology of RD can be better investigated by distinguishing primary deficits from secondary impairments unfolding along development. These exciting and modern investigatory efforts can also indirectly contribute to a centered practice of early and accurate identification and optimal intervention to support the development of foundational pre-literacy skills and fluent reading. In sum, integrating a developmental understanding into the science and practice of reading acquisition and intervention is both possible and necessary.

READING disability; DYSLEXIA; CHILDREN with dyslexia; NEUROBIOLOGY; READING; LITERACY; NEURAL circuitry; COGNITIVE processing of language

Language & Linguistics Compass, 2017, Vol 11, Issue 10, pn/a

1749-818X

Academic Journal

10.1111/lnc3.12252