Evidence of Functional Changes in Brains After Effective Reading Instruction

Abstract

Source: Shaywitz BA, Shaywitz SE, Blachman BA, et al. Development of left occipitotemporal systems for skilled reading in children after a phonologically-based intervention. Biol Psychiatry. 2004;55:926–933.Strong consensus supports the idea that a reading disability represents a deficit in the ability to understand and manipulate the underlying structure of the smallest units of sounds in a language (phonemes).1 A range of neurobiological investigations shows a failure of left hemisphere posterior brain systems to function properly during reading in children and adults with reading disabilities. 2 Functional magnetic resonance imaging (fMRI) uses blood flow to determine which parts of the brain activate during different types of activity, such as a reading task.3 Evidence of a disruption in the normal reading pathways provides a neurobiological target for reading interventions, and a potential method to assess them. Researchers at Yale University, New Haven, Conn, Syracuse University, NY, and Vanderbilt University, Nashville, Tenn, examined whether the provision of a reading intervention intended to improve awareness of the internal structure of spoken words (phonologic knowledge) would improve reading fluency and have an effect on fMRI.A total of 77 right-handed children aged 6.1–9.4 years were recruited: 37 children (22 boys) with reading disabilities received the experimental intervention (EI); 12 children (7 boys) with reading disabilities received a variety of common, mostly school-based reading interventions (CI); and 28 community controls were children without reading problems (CC). All subjects received fMRI scans before and immediately after intervention. The 37 children in the experimental group received an average of 105 hours (86–115) of intervention over 8 months (September-May), while the other 12 children with reading disabilities received various interventions from 1 to 4 days each week, and lasting between 15 and 50 minutes per day.All 3 groups improved in the primary outcome variable of reading fluency as measured by the Gray Oral Reading Test (GORT), which measures a combination of accuracy and rate. The gain by the EI group was significantly greater than that of the CI group, but the 2 other comparisons (CC/EI, CC/ CI) were not statistically significant. Compared with CI, both CC and EI subjects demonstrated increased activation in left hemisphere regions, including the inferior frontal gyrus and the posterior aspect of the middle temporal gyrus. The results for the CC and EI groups were very similar, suggesting that normal and EI subjects developed reading systems to the same degree.The authors conclude that the nature of the remedial educational intervention is critical to successful outcomes in children with reading disabilities, and that the use of their phonologic reading intervention facilitates the development of the fast-paced neural systems that underlie skilled reading.This study supports the findings of other studies4,5 showing fMRI changes after intensive phonologic and morphologic reading intervention. This is the first study of reading intervention that reports effects on both reading fluency and changes in brain function on fMRI, and the first to compare the fMRI effects of a reading intervention to a control group. The strength of this study is in finding improvement in both reading scores and functional assessment of brain systems. Significant limitations, not fully addressed by the authors, include the non-randomized study design: the EI group was from Syracuse, while the 2 community groups (CC and CI) were from Connecticut. Were the gains due to the phonological nature of the experimental intervention or the differences in the amount of instruction? It is difficult to determine the limitations of current “standard” intervention practices for reading disorders in schools based on a sample of 12 subjects provided with a diverse array of interventions. A stronger argument for superiority of one intervention over another will require a large, randomized study in which all subjects come from the same pool. The authors state that it may be a challenge to enroll subjects, since parents of struggling readers are reluctant to have their children participate in a study unless their children have the possibility of receiving effective reading interventions.