Abstracts

Rationale: Abnormalities in amygdala volume are described in pediatric mood (Rosso et al., 2005) and anxiety disorders (Milham et al., 2005), as well as in attention deficit hyperactivity disorder (ADHD) (Plessen et al., 2006), in adults with temporal lobe epilepsy and psychopathology (Satishchandra et al., 2003), and in rats with genetic absence epilepsy (Bouilleret et al., 2009). Given the high rate of anxiety disorders and ADHD in childhood absence epilepsy (CAE) (Caplan et al., 2009), this study compared amygdala volumes in children with CAE to age- and gender-matched normal children, and examined the relationship of amygdala volumes with psychopathology in the CAE group. Since amygdala volume increases during late childhood, albeit more prominently in boys than girls (Giedd et al., 1996), we also compared gender effects on amygdala volumes in the CAE and normal groups. In addition, we determined if amygdala volumes were associated with seizure variables within the CAE group. Methods: Twenty-six children with CAE and 23 normal children, aged 6.6 - 15.3 years, underwent magnetic resonance imaging (MRI) at 1.5 T. The tissue of these MRI images was segmented and total brain volume and amygdala volumes, obtained from manual tracings, were computed. The Kiddie Schedule for Affective Disorders and Schizophrenia was administered separately to each child and parent, and all participants completed the Children Depression Inventory and the Multidimensional Anxiety Scale for Children. In addition, the parents of all participants completed the Child Behavior Checklist, and provided demographic and seizure-related information. Results: Analyses of covariance controlling for demographic variables and total brain volume demonstrated no significant amygdala volume and asymmetry differences between the CAE and normal groups. Gender differences in amygdala measures were similar for the CAE and normal subjects. The CAE children with ADHD had significantly smaller amygdala volumes compared with those with no psychopathology (Wilcoxon test statistic= 50, exact p<0.02) and with those with affective/anxiety disorder diagnoses (Wilcoxon test statistic= 73, exact p<0.05). Moreover, a general linear model revealed that increased seizure frequency, but not other seizure variables, was significantly related to greater amygdala asymmetry (F(1,23) = 9.26, p <0.006) in the CAE group.