Abstracts

Rationale: Idiopathic generalized epilepsies (IGE) are associated with attention and memory deficits that contribute to poor quality of life. We previously showed that self-reported levels of exercise during leisure-time (PEL) correlated positively with performance on a modified flanker task (FT) in a sample of IGE and control participants without epilepsy (HCs). In the current study, we investigated group differences in FT brain activation in a subset of participants who underwent functional magnetic resonance imaging (fMRI). We hypothesized group differences in frontal lobe activation involved in attention, and that higher levels of PEL would be associated with better cognitive performance and decreased fMRI activation.

Methods: Twelve participants with IGE and twelve sex-/age-matched HCs underwent 3T fMRI. Standard fMRI processing and statistical modeling were performed using AFNI. Single-subject general linear modeling was performed to model response to congruent (CON) and incongruent (INC) conditions on FT and to contrast CON vs. INC. Two-sample t-tests (covarying for seizure frequency) were performed to assess fMRI group differences. Signal was extracted for each fMRI cluster showing significant group differences. Participants completed the Baecke Questionnaire to assess PEL levels and the Montreal Cognitive Assessment (MoCA) and Hopkins Verbal Learning Test – Revised (HVLT-R) to assess cognition. Spearman correlations determined relationships between PEL and cognitive performance; only measures showing significant group differences were assessed for relationships with FT fMRI activation. Whole-brain correlations with FT fMRI response and PEL were also performed.

Results: There were no significant group differences in age, sex, years of education, or body mass index. MoCA, PEL, HVLT-R and FT accuracy scores were consistently higher in HCs than IGE participants. IGE participants also exhibited slower reaction times than HCs in FT conditions. PEL showed a negative correlation with reaction time on CON (r=-0.54, p=0.008) and INC (r=-0.52, p=0.011) conditions. Compared to HCs, IGE participants showed decreased activation in the left superior frontal gyrus/superior medial gyrus during CON and INC conditions, and also decreased activation in the right superior frontal gyrus during INC (Figure 1A-B). Activation in these brain regions were not correlated with PEL but showed consistent negative correlations with FT reaction times (r< -0.43, p< 0.05 for all). Whole-brain correlations showed a positive association between PEL and response to INC in the right superior parietal lobule, and response to INC-CON in the cerebellum (Figure 1C).