Group Stability and Reading Profiles of Students With Dyslexia: A Double-Deficit Perspective

This study examined the Double-Deficit Hypothesis (DDH) by classifying students with dyslexia into four distinct groups, comparing group differences on text-level reading tasks, and examining group stability across one school year (fall to spring). Elementary students (N = 109) were administered measures of reading fluency, reading comprehension, and phonological processing across the school year. DDH group membership was determined by the presence of phonological awareness deficits (PD), naming speed deficits (NSD), double-deficits (DD) in both skills, or no deficits for typically developing (TD) readers. The McNemar test was used to determine the stability of DDH group membership. Analysis of covariance was used to compare DDH groups on text-level reading tasks at each time point after controlling for gender. Overall, reading profiles across the fall DDH groups were congruent with DDH theory, but instability was found in the reading patterns and group membership across time. Nearly half (47.71%) of participants changed DDH groups across the school year, and reading skill differences between the single-deficit groups dissipated in the spring. Results provide partial support for the DDH subgroups. More research is needed to understand the utility of the DDH subtypes for future assessment and intervention practices.