Our work depends on volunteers who offer their time to come and participate in our research. We work with schools and thank the leadership, staff, students, and families of the following schools for engaging in our research and research-related activities:
In March 2016, CSL graduate students led a 10th grade science class from the Siena School in a four-day workshop on brain anatomy and imaging methods. Visit The Synapse Project for a write-up of the event.
Thirty-two students from the Jemicy School participated in our research studies. As a result of this, we learned the following:
Changes in Reading Ability and Brain Structure after Instruction
Georgetown University Medical Center Update
This study, published in NeuroImage in 2011, examined whether improvements in reading ability were accompanied by changes in brain structure after a reading intervention in eleven children with dyslexia. The intervention focused on the relationship between letters (and groups of letters) and the sounds they make. It used a 'multi-sensory' approach that included mental tracing of letters while simultaneously naming the letter. This increased in difficulty to multiple letters and syllables as the intervention went on. Read more...
The children in the study showed marked improvement in several reading and reading-related skills (including word naming and passage comprehension) after eight weeks of instruction. Importantly, the improvements were maintained, as there was no decrease in these gains in the eight weeks after the intervention ended. In terms of brain structure, four areas showed increased volume at the end of the intervention as compared to the start. These areas include those involved in memory and mental imagery. Like the improvements in reading skills, these changes in brain structure were maintained after the intervention ended.
Some of the reading skills improvements were found to be correlated with the changes in brain structure. Improvement in phonemic awareness (identifying the sounds within words) was related to increased volume in a part of the brain called the precuneus, which is involved in mental imagery (which is used in the intervention). Improvement in another reading skill, pseudo-word reading (words that can be read but are not real; e.g., lome), was related to increased volume in part of the cerebellum, which can be active during various language-related tasks.
The results of the study show that intense instruction can have positive outcomes in improving reading skills in children who are having trouble learning to read. The improvements last after the instruction period is over, hopefully allowing for future improvement with continued exposure to reading. These reading improvements are accompanied by changes in the brain that may help us further understand how individuals with dyslexia read and how to better improve their reading.
Brain Anatomy of Dyslexia Is Not the Same in Men and Women, Boys and Girls
This study, published in Brain Structure and Function in 2013, is the first to examine anatomical differences, specifically gray matter volume, in the brains of females with and without the common reading disability developmental dyslexia. Read more...
Previous studies of brain anatomy in dyslexia have been confined to all-male or male-dominated samples because the prevalence of dyslexia is 2 to 3 times higher in males than in females; yet the results have been generalized to all people with dyslexia, male and female. In this new study, involving a total of 118 participants, when men with and without dyslexia were contrasted with non-dyslexics, anatomical differences were seen in temporal-parietal cortex, consistent with prior reports. However, the novel parallel comparison of women with and without dyslexia revealed differences not in brain regions associated with language function, but instead in areas that control sensory and motor function. Sex-specific differences in dyslexia were seen not only in adults, but also in children, suggesting that females with dyslexia have their own unique neuroanatomical differences across the lifespan.
Our results raise important questions about whether the etiology of dyslexia is different in males and females and suggest that researchers and practitioners need to consider female dyslexics as a group separate from male dyslexics.
Abnormal Visual Motion Processing is a Consequence and not a Cause of Developmental Dyslexia
There is a longstanding debate about whether the visual symptoms observed in developmental dyslexia (attributed to dysfunction of the visual magnocellular system and measured here via brain activity underlying visual motion perception) have a causal role in this common learning disability. In this study, published in Neuron in 2013, we found a correlation between magnocellular visual system function and reading ability in normal controls. Read more...
We also found a weakness in magnocellular visual system function in dyslexia (as reported in our Nature paper in 1996). However, we provide two types of new evidence that dyslexia is not caused by this magnocellular deficit as has been widely claimed.
First we show that when dyslexic children are compared to younger children matched on reading ability ("reading-level-matched design"), there is no longer a difference between dyslexics and controls, questioning the causality of visual system differences. Secondly, following a language-based reading intervention program, brain activity in the magnocellular system is coupled with reading gains in the dyslexics.
These data demonstrate that the visual magnocellular deficits observed in dyslexia are not the cause of dyslexia. Further, they counter the hypothesis that magnocellular problems are a symptom of dyslexia per se (i.e., co-existing with the language-based problems that drive the reading deficits); rather, they are the consequence of not learning to read, because learning to read mobilizes the visual magnocellular system.
Finally, our observation that gains in reading are followed by changes in brain regions subserving visual motion perception makes an important and independent contribution to a small body of work that has begun to demonstrate that the culturally-imposed process of learning to read results in experience-dependent plasticity in brain areas outside of the reading network.
Dyslexia Impacts Mathematical Processing