Summary
The interictal spike discharges present in rolandic epilepsy has a dominant horizontal dipolar topography, centered near the rolandic area. In order to examine the generator configuration of this focus, we investigated the variation of spike topography in 20 children with rolandic epilepsy of childhood by the dipole localization method (DLM). A quantitative measure ("stability index" or SI) of the degree of source fluctuation was devised, based on the consistency of the source parameters (location, direction and magnitude) over contiguous time points. A high SI was associated with overlapping source locations and parallel directions over many time points, while a low SI was seen with poor and variable solutions. At the peak and trough of the spike, the corresponding sources were found to have different locations. If the patients were separated into those with and without neurological findings, the mean times at which stable sources existed were significantly different: 35 and 150 ms respectively after the spike apex. Further, the group without abnormal neurological findings tended to have higher values of SI. These results suggest that such stability analysis allows measurement of the spatial and temporal extents of source estimates. These results further support the hypothesis that the topographic behaviour of a spike focus is closely associated with its clinical characteristics.
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References
Gastaut, H. "Benign" or "functional" (versus "organic") epilepsies in different stages of life: an analysis of the corresponding age-related variations in predisposition to epilepsy. Neurosciences, 1982, 35: 17–44.
Gregory, D. and Wong, P.K.H. Topographic analysis of the centrotemporal discharges in benign rolandic epilepsy of childhood. Epilepsia, 1984, 25(6):705–711.
Lehmann, D. and Skrandies, W. Reference-free identification of components of checkerboard-evoked multichannel potential fields. Electroenceph. Clin. Neurophysiol., 1980, 48:609–621.
Lerman, P. and Kivity, S. Benign focal epilepsies of childhood. In: T.A. Pedley and B.S. Meldrum (Eds.), Recent Advances in Epilepsy. Vol. 3, 1986, 137–156, Churchill-Livingston, New York, N.Y.
Loiseau, P., Pestre, M., Dartigues, J.F., Commenges, D., Barberger-Gateau, C. and Cohadon, S. Long-term prognosis in two forms of childhood epilepsies: typical absence seizures and epilepsy with rolandic (centrotemporal) EEG foci. Ann. Neurol. 1983, 13(6):642–648.
Lombroso, C. Sylvian seizures and midtemporal spike foci in children. Arch. Neurol., 1967, 17:52–59.
Schneider, M. Effect of inhomogeneities on surface signals coming from a cerebral current-dipole source. IEEE Transactions On Biomedical Engineering, 1974, 21:52–54.
Wong, P.K.H., Bencivenga, R. and Gregory, D. Statistical classification of spikes in benign rolandic epilepsy. Brain Topography 1989, 1(2):123–129.
Wong, P.K.H., Baff, M. and Weinberg, H. Source locations in VEP mapping. Brain Topography 1989, 1(2):148.
Wong, P.K.H. and Weinberg, H. Source estimation of scalp EEG focus. In: G. Pfurtscheller and F. Lopes da Silva (Eds.), Functional Brain Imaging. Hans Huber Publishers, Toronto, 1988, 89–95.
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Wong, P.K.H. Stability of source estimates in rolandic spikes. Brain Topogr 2, 31–36 (1989). https://doi.org/10.1007/BF01128841
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DOI: https://doi.org/10.1007/BF01128841