P-EV003. Origin of giant somatosensory evoked potentials (SEPS) in benign adult familial myoclonus epilepsy (BAFME) using principle component analysis

Abstract

Introduction. Both benign adult familial myoclonus epilepsy (BAFME) and Unverricht- Lundborg disease (ULD) belong to progressive myoclonus epilepsy with giant somatosensory evoked potentials (SEPs), but their clinical courses are different from each other. We aimed to delineate the generator source of giant SEP P25 and their high frequency oscillations (HFOs) in patients with BAFME and ULD using principal component analysis (PCA). Methods. PCA was performed on giant SEPs and their HFOs obtained by multi-channel scalp recordings of five patients with BAFME and four patients with ULD. To identify HFOs, SEPs were digitally filtered using a 400–1000 Hz band-pass filter. From the peak latencies of the first or second principal component (PC), we identified the corresponding peaks of original P25 and HFOs near P25 (P25-HFOs). Then, from the polarity and distribution of first and second PCs, the P25 and P25-HFOs were estimated as tangential dipole with phase reversal between frontal and parieto-occipital electrodes or as radial dipole without phase reversal. Results. All five patients with BAFME had P25-HFOs, and both P25 and P25-HFOs were estimated as radial dipole, whereas in all four patients with ULD, P25-HFOs was not present and the estimated components of P25 varied among patients. Conclusion. The generator sources of both P25 and P25-HFOs in giant SEPs in patients with BAFME are radial dipole, which suggests crown origin, and P25-HFOs did not occur in patients with ULD. The generator mechanism of giant SEP P25 and P25-HFOs of BAFME may be different from that of ULD.