Abstracts

Efforts to block seizures using electricity have been restricted to alternating charged-balanced currents. The ability of non-balanced charges (DC) to reset oscillations[apos] phases and their therapeutic applications have been amply demonstrated in cardiology. A method for automated delivery of DC for seizure blockage and preliminary results are presented., Broad-band ECoG (DC-10 kHz) recorded from rats treated with 3-MPA is fed into a PC with an algorithm that quantifies DC (0-0.5 Hz) and AC (15 Hz-2 kHz) seizure components, to which certain constraints are applied to maximize sensitivity and specificity or speed of detection. A novel window-based [quot]rhythmicity index[quot] (RI), was added to the stimulation logic. The algorithm[apos]s output triggers local DC pulses to the epileptogenic zone. Tissue histology of stimulated vs. non-stimulated tissue is being performed., DC stimulation was reliably/timely delivered in response to DC shifts and AC seizure components, which usually follow the slow shifts.
Single or brief ([lt]100 ms) high frequency ([gt]100 Hz) DC pulses blocked seizures (Fig. 1AB). RI narrowed the stimulation [quot]phase-space[quot] increasing efficacy., Local DC stimulation for seizure blockage appears promising and should be explored further. Detection of DC and AC activity, which requires broad-band capabilities, expand the window during which stimulation may be delivered, potentially enhancing efficacy. Susceptibility to seizure blockage may depend on the instantaneous value of RI.[figure1], (Supported by a grant from the Epilepsy Project. Experiments were performed using Synamps2 loaned by Compumedics/Neuroscan, El Paso, TX.)