Prefrontal mediation of the reading network predicts intervention response in dyslexia

Abstract

A primary challenge facing the development of interventions for dyslexia is identifying effective predictors of intervention response. While behavioral literature has identified core cognitive characteristics of response, the distinction of reading versus executive cognitive contributions to response profiles remains unclear, due in part to the difficulty of segregating these constructs using behavioral outputs. In the current study we used functional neuroimaging to piece apart the mechanisms of how/whether executive and reading network relationships are predictive of intervention response. We found that readers who are responsive to intervention have more typical pre-intervention functional interactions between executive and reading systems compared to nonresponsive readers. These findings suggest that intervention response in dyslexia is influenced not only by domain-specific reading regions, but also by contributions from intervening domain-general networks. Our results make a significant gain in identifying predictive bio-markers of outcomes in dyslexia, and have important implications for the development of personalized clinical interventions.

Keywords: Dyslexia; Intervention; Intervention response prediction; Prefrontal cortex; fMRI.

Figure 1. Left ventral MTG has greater connectivity to right IFG in DYS-R > DYS-NR

(a.) In DYS-R > DYS-NR, left ventral MTG activation correlates with right IFG activation, an area which has previously been implicated in long-term reading gains (Hoeft et al., 2011). (b.) Scatterplot of intervention response (BR ss change) and direct connectivity between the left ventral MTG and right IFG regions. Results displayed at p-corrected < 0.05 (p-uncorrected < 0.005; k = 107).

Figure 2. In DYS-R > DYS-NR, left dlPFC activation has greater interactions with reading network connectivity

(a.) In DYS-R > DYS-NR, a one-unit increase in dlPFC activation corresponds with increased correlations in the reading network, including between left ventral MTG and left IPL (top), left IFG and right IFG (bottom), and left IFG and L IPL (not shown). (b.) The interaction effect seen in (a.) is also reflected in a continuous measure of response, as shown by a scatterplot of intervention response (BR ss change) and the interaction between dlPFC activation and connectivity between the seed areas represented in (a.). Results displayed at p-corrected < 0.05 (p-uncorrected < 0.005; k = 107).