Abstracts

Rationale: Children with partial seizures differ in their seizure semiology, treatment, and etiology from those with a primary generalized epilepsy like childhood absence epilepsy. Yet there may be similarities, for example, in the poorly understood mechanism of seizure initiation. The differences in standard EEG between the two groups are stark. Chaotic measurements are another approach that has been used to describe dynamic systems like EEG. Such measurement can be useful in finding unexplained factors in a dynamic system. Methods: There were 12 children with EEG's meeting the ILAE criteria for childhood absence epilepsy. There were 2 boys and 10 girls. In the partial seizure group there were 20 children. There were 50 seizures selected for the analysis. All data were acquired using Nicolet BMSI hardware to record a 24 channel (EEG) using the international 10/20 of Electrode placement. EEG records were reviewed using 15 mV per millimeter sensitivity with high voltage filter at 15 Hz and low frequency filter set at 1.0 Hz. The F7 channel of the EEG was selected for actual analysis. The EEG seizure data was converted to a .cvs file using Nivue. The .cvs file was read by a MatLab macro and macro for phase space plotting of the seizures. The .cvs file of the seizures was also converted to .dat file for processing by RRChaos to produce the dynamic measures of entropy, eigen values, and for the generation of baseline noise. Results: There are similarities in the pattern of the dynamic systems measurements. These similarities include a shared Eigen value with seizure onset, complex pattern of entropy changes, and reduced dimensionality. Phase space plots also had similar patterns of development. All these chaotic changes were compared to randomized noise controls and were significantly different. Conclusions: These chaotic measures have detected similarities in the dynamics of the EEG, despite clinical differences in their EEG s baseline and the abnormalities, molecular and genetic etiologies, and treatments, and outcomes. Given these similarities, these data suggest that there is a common uderlying systems change in the dynamics of the pathophysiology at the onset of their seizures.