CEREBRAL BLOOD-FLOW DURING SPIKE-WAVE DISCHARGES

We used the (133)xenon method to assess cerebral blood now (CBF) durin g generalized spike-wave discharges in a patient with an uncommon form of generalized epilepsy with persistent spike-wave discharges. CBF me asurements were made under four conditions with repeated measures: nor mal 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 globall y diminished, CBF was less decreased in the frontal lobes and more dec reased in the parietal lobes during spike-wave discharges. CBF increas ed to baseline levels during the cognitive activation task. The decrea se 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 lob ar disparities in neuronal firing patterns. The theta state noted is n ovel and intermediate between normal and spike-wave.