Predicting and Evaluating Treatment Response: Evidence Toward Protracted Response Patterns for Severely Impacted Students With Dyslexia.

Great strides have been made in the development of effective methods of instruction for children with dyslexia. However, individual response to treatment varies, and weaknesses persist for some students with dyslexia despite otherwise effective instruction. Continued efforts are needed to support the prospective identification of poor response, particularly in routine intervention settings. The current study addressed whether indicators of dyslexia risk as outlined by hybrid diagnostic models predict response in children who received Tier 3 dyslexia intervention in their schools. The program's efficacy has been previously documented in remediating reading abilities in children with dyslexia. Data were examined from 115 elementary-age children who received routine Tier 3 dyslexia intervention in their schools. Logistic regression revealed powerful effects of preintervention fluency and gender in predicting response, with weaker effects of decoding and rapid naming. Attention-deficit/hyperactivity disorder status also played a role in predicting response. Phonological awareness and listening-reading comprehension discrepancy did not predict response. Profile analyses indicated near- and far-transfer of skill for the adequate response group, whereas growth in the poor response group was limited to near-transfer. Findings support a continuum of severity that may be associated with less robust growth and generalization over the course of the intervention.

The multiple deficit model of dyslexia: what does it mean for identification and intervention?

Research demonstrates that phonological skills provide the basis of reading acquisition and are a primary processing deficit in dyslexia. This consensus has led to the development of effective methods of reading intervention. However, a single phonological deficit is not sufficient to account for the heterogeneity of individuals with dyslexia, and recent research provides evidence that supports a multiple-deficit model of reading disorders. Two studies are presented that investigate (1) the prevalence of phonological and cognitive processing deficit profiles in children with significant reading disability and (2) the effects of those same phonological and cognitive processing skills on reading development in a sample of children that received treatment for dyslexia. The results are discussed in the context of implications for identification and an intervention approach that accommodates multiple deficits within a comprehensive skills-based reading program.

Take Flight: the evolution of an Orton Gillingham-based curriculum.

Thirty years ago in this journal, Aylett Royall Cox reported on the development of Alphabetic Phonics, a revision of the existing Orton Gillingham treatment for children with dyslexia. This paper continues that discussion and reports on the evolution of that curriculum as it is represented in a comprehensive dyslexia treatment program informed by intervention research. The paper describes the curriculum and reports data from a hospital-based learning disabilities clinic that provides qualified support for treatment efficacy and the value of added comprehension instruction. The results are then discussed in the context of current and future issues in dyslexia intervention.

Predicting Growth in Word Level Reading Skills in Children With Developmental Dyslexia Using an Object Rhyming Functional Neuroimaging Task.

An object rhyming task that does not require text reading and is suitable for younger children was used to predict gains in word level reading skills following an intensive 2-year reading intervention for children with developmental dyslexia. The task evoked activation in bilateral inferior frontal regions. Growth in untimed pseudoword reading was associated with increased pre-intervention activation of the left inferior frontal gyrus, and growth in timed word reading was associated with pre-intervention activation of the left and right inferior frontal gyri. These analyses help identify pre-intervention factors that facilitate reading skill improvements in children with developmental dyslexia.

Functional connectivity between the left and right inferior frontal lobes in a small sample of children with and without reading difficulties.

Individuals with dyslexia often demonstrate bilateral inferior frontal lobe activation while performing basic reading tasks. To investigate these findings, functional connectivity analyses were conducted on fMRI data collected from children with dyslexia, who did and did not respond well to treatment, and from non-impaired readers. Analysis of active and resting-state fMRI data across 15 participants revealed functional connections between the inferior frontal regions in non-impaired readers and treatment responders, but not in treatment non-responders. Analyses incorporating DTI data revealed associations with anterior corpus callosum structures. These results suggest that bilateral frontal functional connectivity is normative and may facilitate treatment response.

Brain connectivity in non-reading impaired children and children diagnosed with developmental dyslexia.

Diffusion Tensor Imaging (DTI) was used to investigate the relationship between white matter and reading abilities in reading impaired and non-reading impaired children. Seventeen children (7 non-reading impaired, 10 reading impaired) participated in this study. DTI was performed with 2mm isotropic resolution to cover the entire brain along 30 noncollinear directions. Voxelwise analyses were conducted on data processed through Tract Based Spatial Statistics (TBSS). The data replicated previous results seen across multiple studies and extended findings to include measures of both real word and pseudoword decoding. Negative correlations were observed in the left posterior corpus callosum between fractional anisotropy (FA) values and both measures of decoding. Positive correlations between FA values and real word and pseudoword decoding were observed in the left superior corona radiata. This extension of findings regarding correlations between the corona radiata and reading skills suggests an important direction for future research into the neurological substrates of reading.

Differentiating the neural response to intervention in children with developmental dyslexia.

Developmental dyslexia is associated with functional abnormalities within reading areas of the brain. For some children diagnosed with dyslexia, phonologically based remediation programs appear to rehabilitate brain function in key reading areas (Shaywitz et al., Biological Psychiatry 55: 101-110, 2004; Simos et al., Neuroscience 58: 1203-1213, 2002). However, a non-trivial number of children diagnosed with dyslexia fail to respond to these interventions (Torgesen, Learning Disabilities Research & Practice 15: 55-64, 2000). A cross-sectional fMRI study investigating post-treatment effects was conducted in an effort to better understand differences in brain function between treatment responders and non-responders. Educational testing and brain activation measured after treatment suggested that the reading intervention used in the present study rehabilitated several basic level reading processes in all participants diagnosed with dyslexia. However, activation in the left inferior parietal lobe differentiated treatment responders and non-responders in comparison to non-impaired readers. Children with persistent deficits in single word decoding (treatment non-responders) demonstrated significantly less activation in the left inferior parietal lobe when compared to non-impaired readers.

Verbal and visual short-term memory in children with arithmetic disabilities.

With the exception of the explication of the Nonverbal Learning Disability Syndrome, our knowledge of cognitive characteristics of children with isolated arithmetic (A) disabilities contrasted with those with comorbid arithmetic and reading (AR) disabilities is limited. Of the existing studies, most suggest that visual deficits are characteristic of Subtype A. This study examined short-term memory in 45 children who were classified into these two subtypes. Children in Subtype A displayed better verbal memory on some tasks than children in the AR subtype, but no subtype differences in visual memory were found. Counter to our hypothesis, children in Subtype A did not display relatively poorer visual memory than verbal memory. These results suggest a mixed neuropsychological profile, and the absence of visual short-term memory weaknesses as descriptive of the A subtype.