Poster Session F, Tuesday, March 26, 8:00 – 10:00 am, Pacific Concourse
Volumetric Differences of the Thalamus in Developmental Dyslexia
Mykayla Jeter1, C. Nikki Arrington1, Robin Morris1; 1Georgia State University
Learning and attention disorders are the most common issues impacting learning in school-aged children. Research indicates that developmental dyslexia(DD) and Attention Deficit Hyperactivity Disorder(ADHD) are associated with structural brain differences such as decreased volume in thalamic nuclei compared to typically developing readers(TDR). The aim of the current study was to further evaluate volumetric differences of the thalamus in children with DD only, and DD+ADHD. It was hypothesized that children meeting study criteria for co-morbid DD+ADHD would have reduced thalamic volume compared to children with DD only, and TDR. As part of a larger study, we assessed volumetric differences in the thalamus of 127 elementary-school aged children (male=72, mean age=9.13) obtained from structural brain images processed through Freesurfer software. Participants were classified into one of three groups (TDR, DD, and DD+ADHD) based on study diagnostic criteria using reading tests and ADHD behavioral ratings. A one-way ANOVA was conducted to compare the volumetric differences in the left and right thalamus between groups. A significant difference in left thalamus volume was found, F(2,124)=4.54,p<.05,ղ2=.068,HSD=401.32. Post hoc comparisons indicated a significant difference between DD and TDR groups only. No other significant differences were found. Results indicate thalamic volume in co-morbid DD+ADHD was not different from the volume in DD only, while DD volume decreased compared to TDR children. Previous research indicates the left hemisphere of the brain as the primary center for reading and language networks supported by left hemisphere thalamic nuclei. Decreased volume in this brain structure may contribute to reading impairments in DD.
Topic Area: NEUROANATOMY