Cerebral blood flow during spike-wave discharges

We used the 133xenon method to assess cerebral blood flow (CBF) during generalized spike-wave discharges in a patient with an uncommon form of generalized epilepsy with persistent spike-wave discharges. CBF measurements were made under four conditions with repeated measures: normal EEG, continuous theta state, continuous spike-wave state at rest, and continuous spike-wave discharges during performance of a cognitive activation task. CBF was mildly reduced (5.7%) during the theta state and decreased further (12%) in the spike-wave state. Although globally diminished, CBF was less decreased in the frontal lobes and more decreased in the parietal lobes during spike-wave discharges. CBF increased to baseline levels during the cognitive activation task. The decrease in CBF suggested that the generalized spike-wave discharges caused a net decrease in cortical metabolic demand and neuronal activity. The differences in lobar CBF during spike-wave discharges may reflect lobar disparities in neuronal firing patterns. The theta state noted is novel and intermediate between normal and spike-wave.