Abstracts

Structural imaging studies describe late maturation of fronto-temporal regions involved in the integration of language and thought in normal children with an age-related decrease in gray matter but increase in white matter volumes (Gogtay et al., 2004; Sowell et al., 2003). This study examined if the impaired discourse skills or thought disorder found in children with cryptogenic complex partial seizures (CPS) (Caplan et al., 2006) is related to abnormal volumes of frontal and temporal regions associated with language compared to age and gender matched normal children., 28 children with CPS and 34 children without epilepsy, aged 5-16 years completed brain MRI scans at 1.5 Tesla. Tissue was segmented and total brain, frontal lobe, frontal parcellation and temporal lobe volumes were computed. Thought disorder measures, IQ, language scores, and seizure information were also obtained on each patient., ANOVAs of the thought disorder scores with demographic, IQ, and language variables in the model revealed significantly higher thought disorder scores ([underline]F[/underline][sub]1,57[/sub] = 14.02, [underline]p[/underline] [lt] .004), as well as larger orbital frontal white matter volumes ([underline]F[/underline][sub]1,49[/sub] = 4.57, [underline]p[/underline] [lt] 0.03) in the CPS compared to the normal group. General linear models with thought disorder, demographic variables, IQ scores, and language scores as predictors demonstrated a trend for higher thought disorder scores to be related to larger gray matter volume of the orbital frontal gyrus (OFG) (F [sub]1,29[/sub] = 3.84, p [lt] .05) in the normal group. In the CPS group including also seizure variables in the model, we found a significant association of higher overall thought disorder scores with smaller gray (F [sub]1,17[/sub] = 13.75, p [lt] .002) and white matter volumes (F [sub]1,17[/sub] = 4.55, p [lt] .05) in the OFG, smaller white matter volumes of superior temporal gyrus (STG )(F [sub]1,16[/sub] = 24.54, p [lt] .0001), and larger gray matter volumes of Heschel[apos]s gyrus (HG) (F [sub]1,21[/sub] = 6.86, p [lt] .02)., Given the low base rate of thought disorder in normal children, our findings imply that impaired maturation of OFG (i.e., larger gray matter volumes) might be related to abnormal discourse skills in normal children. However, the findings in the CPS subjects with thought disorder, suggest that the discourse deficits of these children might reflect increased vulnerability of language related brain regions, STG and HG, as well as OFG to the impact of CPS on normal development., (Supported by NS32070 and MH067187.)