Resting state signal latency assesses the propagation of intrinsic activations and estimates anti-epileptic effect of levetiracetam in Rolandic epilepsy

Abstract

PurposeWe assessed the potential of resting-state fMRI lag analysis (RSLA) in detecting epileptic activation and in estimating anti-epileptic effects of Levetiracetam (LEV) in Rolandic epilepsy. MethodsForty-three children with Rolandic epilepsy underwent simultaneous EEG-fMRI. They were grouped into LEV vs drug-naïve groups according to their medication, and into patients who showed or did not show central-temporal spike (CTS) discharges during scans. We calculated the lag structure of rs-fMRI for all patients and assessed interactions with drug (LEV vs. drug-naïve) and CTS status (CTS vs. no-CTS). We furthermore assessed correlations between lag values and number of CTS and medication conditions. ResultsRSLA analysis indicated earlier intrinsic activations in bilateral Rolandic areas when CTS occurred. More frequent epileptic discharges were correlated with earlier intrinsic activations (r=-0.46, p = 0.03 left Rolandic). Patients with LEV therapy, on the other hand, displayed delayed intrinsic activity in Rolandic areas compared to drug-naïve patients ConclusionOur RSLA analysis indicated an association between centro-temporal spikes and earlier hemodynamic activations in epileptogenic regions in Rolandic epilepsy, which were counteracted by LEV treatment. As it allows for the mapping of propagation features of intrinsic activity and drug-effects, our findings suggest potential of lag based analyses in detecting focus localization and estimating treatment effects.