The Speech/Language Genetics Lab in the College of Health Solutions at Arizona State University focuses on the interactions among genetic variations, brain structures and functions, biomarkers, and communication behaviors.

Why do we care? Because some day, this knowledge will lead to the development of earlier, more preventive, and more finely tuned intervention approaches for individuals with severe speech, language, and reading disorders. Improving outcomes is the ultimate goal.

Among our current lab members is a Ph.D. student who is enrolled in ASU's new Ph.D. concentration "Translational Genetics of Communication Abilities (TGCA)," several honors students enrolled at Barrett The Honors College who are working on thesis projects, as well as several other honors students and research assistants. All are actively and competently working on projects related to the genetic and behavioral studies of speech, language, and reading disorders. Our lab isn't made of instruments and data, it's made of the people who make it all happen! You guys rock!

Here are a few examples of our work:

In a sample of adults with dyslexia and adults with probable histories of severe speech sound disorders, we showed that they had difficulty with the sequential order of things, for instance they tended to imitate nonwords with the sounds in the nonwords out of order, and when they were reading nonwords, they tended to say the words with the letters out of order (Peter et al., 2017; Peter, 2017). We hypothesize that this sequential processing deficit is a biomarker of both dyslexia and apraxia and that it results from various genetic variations that change the way the cerebellum works. We are currently in the process of analyzing MRI data from individuals with dyslexia to show direct evidence of cerebellar changes.

In a sample of adults with dyslexia and typical controls, we showed that many of the adults with dyslexia had an atypical electrophysiological brain response to the second tone in a set of two tones (Peter, McCollum, Daliri & Panagiotides, 2019). Typically, when we hear two tones in rapid succession, our brains respond to the first tone with a strong evoked response potential (ERP) but much less so to the second tone - our brains suppress the response to the second tone because it is repetitive, and this suppression happens were quickly, within the first 100 milliseconds after the onset of the tone. Some individuals with dyslexia are not able to suppress the novelty response until later, at 200 milliseconds. Our ERP study adds a high-resolution temporal account of diminished neural adaptation to a recent MRI account of the same phenomenon (Perracchione et al., 2016).

Copy-number variations (CNVs) are chromosomal changes where small sections of a chromosome are missing or duplicated. Where a piece of chromosome was deleted, the person carries just one copy of that section instead of the typical two copies; a duplication leads to three copies instead of two. We all carry many of these CNVs and most of them have no effect on our health and abilities whatsoever. In some cases, however, we found that CNVs can cause disorders of speech and/or language. We described a child who was missing one entire copy of the BCL11A gene on chromosome 2 had childhood apraxia of speech (Peter et al., 2014), and two children who were missing pieces of chromosome 6 had childhood apraxia of speech and some difficulties with verbal expression (Peter et al., 2017).