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Poster A2, Wednesday, November 8, 10:30 – 11:45 am, Harborview and Loch Raven Ballrooms

Verbal and Nonverbal Fluency Predicts Volume of the Anterior Cingulate Gyrus

Jennifer E. Schlak1, Hannah L. Travis1, Andrew E. Molnar1, Ruchi Brahmachari1, George W. Hynd2, Michelle Y. Kibby1;1Southern Illinois University-Carbondale, 2Oakland University

Objective: Children with dyslexia may have deficits in verbal fluency compared to typically developing children (Cohen et al., 1999). Researchers suggest that verbal fluency is related to frontal lobe functioning (Frith et al., 1991). The anterior cingulate gyrus is not as commonly associated with dyslexia compared to various regions in the frontal lobes, although the anterior cingulate is part of some frontal lobe networks (Bonelli, & Cummings, 2007). Less is known about fluency in relation to the anterior cingulate. Therefore, the purpose of this study was to perform an exploratory analysis between fluency measures and bilateral anterior cingulate volumes to determine if fluency is related anterior cingulate volume in a mixed sample. Method: Data was collected during a study focused on dyslexia (NIH/NIHCD R01, HD26890). Brain tracing was conducted during a separate grant (NIH/NICHD R03 HD048752). Forty-two children from ages 8 to 12 years completed a neuropsychological battery and an MRI scan. About half had dyslexia (52%). The sample was largely Caucasian (84%) and male (67%). Fluency was measured though NEPSY Design Fluency, as well as the Semantic and Phonemic portions of NEPSY Verbal Fluency. The TONI-3 and CTOPP RAN were included as two non-“executive” measures that may be related to frontal lobe functioning. Not all participants had all measures. Three-dimensional, T1 weighted images were collected via a 1.5T GE Sigma scanner. The cingulate was traced on every slice in the sagittal plane using Crespo-Facorro et al. (1999) as a guideline. Then, the cingulate was separated into three regions, and the anterior region ran from the anterior commissure through the termination of the anterior portion of the cingulate. Inter-rater reliability was > 0.90. Results: Two Backward regressions were used to examine the relationship between Design Fluency, Semantic and Phonemic Fluency, the TONI-3, and RAN with anterior cingulate volume (for both the left and right hemispheres). We found that the TONI-3 (β=-.32, p=.079) and semantic fluency (β=.36, p= .047) predicted right anterior cingulate volume (adjusted R2=-.15, F(2, 26)=3.51, p=.045) in the final equation. No independent variables predicted left anterior cingulate volume. Conclusion: Semantic fluency and the TONI-3 were the only predictors of right anterior cingulate volume. Concerning semantic fluency, some research suggests that this task uses bilateral frontal lobes (Zajac-Lamparsaka et al., 2016). However, there is some evidence to suggest that semantic fluency occurs more often in the left hemisphere (Jones-Gotman & Milner, 1977), even though our study suggests significance for the right hemisphere, This could be due to the nature of our study, as approximately half of the participants had dyslexia. These children could have been compensating for left hemisphere dysfunction by using their right hemisphere more. In terms of the TONI-3, our results show an inverse relationship between right hemisphere volume and nonverbal intelligence. This could be because approximately three-quarters of the population had a clinical diagnosis, which may lead to different results compared to when only controls are used. It also could be spurious, as it was only a trend.

Topic Area: Control, Selection, and Executive Processes

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