Abstracts

Rationale: The symptomatogenic zone/network producing seizures with frenetic motor automatisms (hypermotor seizures) is not well understood. We examined ictal cerebral blood flow in patients with hypermotor seizures using single photon emission computed tomography (SPECT) to identify significant cortical and subcortical hyperperfusion patterns. Methods: All patients injected with premixed 99mTc-hexamethyl-propylene-amine-oxime (HMPAO) during a hypermotor seizure during presurgical epilepsy evaluation between 2000 and 2005 were identified. Spatial pre-processing and statistical analysis were performed of their ictal-interictal 99mTc-HMPAO-SPECT using statistical parametric mapping (SPM 2). 99mTc-HMPAO-SPECT of the patients with right epileptogenic focus was transposed right to left in order to evaluate all patients as a single group. Hyperperfused regions with corrected cluster-level significance p<0.05 (voxel threshold p=0.01, extent threshold≥125) were considered significant. Results: Seven patients aged 16 to 43 years with frontal (n=4) or temporal (n=3) ictal onset were studied. 99mTc-HMPAO was injected 5-54 seconds (mean 22 seconds) after seizure onset. Mean seizure duration was 63 seconds (range 9 - 157 seconds). SPM analysis showed two clusters of significant hyperperfusion; one involving bilateral frontomesial regions, cingulate gyrus, caudate and corpus callosum, another involving ipsilateral temporal pole, mesial temporal structures, fronto-orbital region, insula and basal ganglia (Figure 1). Conclusions: While hypermotor seizures can occur in patients with epileptic foci in various brain regions, activation of both frontal and temporal cortex seems to be involved in the generation of this semiology. We suggest that hypermotor seizures result from seizure spread to a brain network involving anterior mesial frontal, cingulate, orbitofrontal and temporal cortex.