Children with reading disability can demonstrate different behavioral patterns or different reading disability profiles. Characterizing these profiles could be important for understanding the reason(s) for reading disability. Large samples sizes are often necessary for profile studies and for that reason researchers may try to pool data from many different research sites. Unfortunately, there is often missing data in large multi-site data sets that can be problematic for identifying different reading profiles, especially when the missing data are critical for differentiating between the reading profiles. We collected test scores from previous studies on reading development and disability to create a large data set. We tested different approaches for dealing with missing data to statistically estimate the missing data using a synthetic data set where we knew the reading profile for each case and then demonstrated the effectiveness of the methods with the real data (726 subjects). These methods can now be used to examine if there are reading disability profile differences in brain anatomy in this data set, for example. In addition, these methods can also be used for identifying profiles when there is missing data in other large data sets. You can read about the details of this study in our manuscript: Reading Profiles in Multi-Site Data with Missingness, which was published online in Frontiers in Psychology. https://www.frontiersin.org/articles/10.3389/fpsyg.2018.00644/full
Cognitive Persistence
The motivation to overcome adversity is critical for achieving goals in life. We recently developed a persistence metric to assess the ability to overcome adversity during a cognitive task. This metric is based on Wisconsin Card Sorting Task (WCST) performance. The WCST is typically used to measure whether people can learn new rules and shift their behavior. This requires working memory and problem solving skills. It also requires persistence. People have to overcome the adversity of finding out that they have made an error on the task and figure out how to make a correct response. We describe this method for measuring cognitive persistence in a recent article published in the journal Neuropsychologia. We also demonstrate that cognitive persistence predicts brain activity in frontal cortex during a challenging word recognition task. This measure could be important for understanding who is working their hardest to perform a task and perhaps predict who will benefit most from interventions.
Gray Matter Predictors of Reading Disability
As described in a recent eNeuro manuscript, we examined the consistency of gray matter findings from published reading disability studies and then attempted to replicate those findings in a relatively large multi-site dataset. This study was part of a larger project to establish methods for multi-site studies. Orbitofrontal and superior temporal sulcus gray matter volume was consistently lower in people with reading disability compared to controls across published studies and in the multi-site dataset. Results from the multi-site dataset were due to reading disability cases with relatively low total brain volume. It appears then that the most consistent gray matter findings in the reading disability literature are driven by cases with low total gray matter volume. Interestingly, the orbitofrontal and superior sulcus gray matter effects were in locations where migrational errors were observed in post-mortem brains from people who had reading disability,; migrational errors that were most pronounced for a case with the lowest brain weight (Galaburda et al., 1985) . For those also interested in multi-site methods, please consider eNeuro manuscript as an example of how to deal with missing data across different research sites.
Bilateral Perisylivan Syndrome Case with a Dyslexia Profile
As part of our project to develop methods for multi-site studies, we unexpectedly received data collected from a child with Bilateral Perisylvian Syndrome (BPS). This was unexpected for a dataset involving children with dyslexia because BPS often presents with epilepsy, mental retardation, and motor impairments. This case did not exhibit these more severe phenotypes and instead had relatively specific deficits on measures of phonological processing tasks compared to higher level language and cognitive abilities. This observation is important because it shows that the BPS clinical profile can include relatively mild impairments that includes reading disability. Additional details about this case and BPS have been published in the journal Cortex. 