Figure 4.
Longer epilepsy duration and higher seizure frequency are associated with decreased functional connectivity. (A) Global functional connectivity, estimated by mean imaginary coherence across all brain voxels, is negatively related to epilepsy duration in patients with focal epilepsy (R2 = 0.229, P < 0.001). (B) A negative relationship is also observed between the frequency of consciousness-impairing seizures and mean imaginary coherence (R2 = 0.121, P < 0.01). For A and B, units are arbitrary, n = 61 patients with MTLE and FNE, and line of best fit is shown with 95% CI. (C and D) Regional maps of RSFC regressed by epilepsy duration (C) or seizure frequency (D) reveal a negative relationship to connectivity in the frontal lobes, particularly left prefrontal and orbitofrontal cortex. For C and D, connectivity maps represent linear regression analysis (threshold P < 0.01, FDR-corrected) of alpha-band imaginary coherence in all 61 patients, overlaid on a 3D-rendered template brain.