Changes in epileptic spike configuration associated with attainment of seizure control.

This study provides preliminary evidence that computer-derived parameters of interictal spike waveforms can be used to assess seizure hazard in a quantitative manner. Thirteen children with spike foci and simple or complex partial seizures were studied before and during treatment with carbamazepine or phenobarbital; spike parameters were determined from 5- to 30-minute electroencephalographic samples obtained during non-rapid eye movement sleep. Measurements included spike amplitude, duration, and sharpness, and a mathematical combination of these three parameters (the composite spike parameter). Achievement of seizure control was associated with a decrease in spike amplitude, duration, and composite spike parameter, and an increase in normalized sharpness, compared to baseline values. These results suggest that this method may provide a prospective means for estimating drug efficacy that can be applied shortly after attainment of steady-state serum drug levels.