Usefulness of Neuroimaging Studies for Localization of the Epileptogenic Focus in Patients with Frontal Lohe Epilepsy Manifesting as Complex Gestural Automatisms

Abstract

Purpose: The goal of this study was to evaluatc the usefulness of ncuroimaging studies for localization of thc epileptogenic focus in patients with frontal lobe epilepsy (FLE). The clinical manifestations werc complex partiel seizures, characterizedd by kicking and thrashing, groaning, occurrence in clusters, being brief (lasting for <40 seconds), and cnding with minimal postictal confusion. Methods: Thc subjects werc 7 patients, aged 1040 ycars (mean agc, 24.3), with complex partial seizurcs, undergoing preoperative evaluations for intractable seizures. All seizurcs wcre documcuted as conforming to complcx geslural automatism by simultaneous EEG‐VCR recordings. We asscssed the clinical features, interictal and ictal electroencephalograms (EEGs), and results of magnetic resonance imaging (MRI), and interictal PVTc ethyl cysteinate dimcr (ECD) singlc photon emission computed tomography (SPECT). Additionally, we studied ictal ECD SPECT findings in 4 patients. We compared the usefulness of EEG, MRI, and SPECT for localization of thc cpileptogenic focus. Results: Thc patients comprised 6 nialcs and I female. The agc at seizurc onset was 1–25 years (mcan, 10.5). One patient had a family history of febrilc seizures and another of anoxia at birth. One patient had a history of ideas of persecution and refercnce. The results of neuropsychological evaluation revealed that their full intelligence quoticnt varied from 51–1 I I (mcan 88). Seizure frequencics at initial consultation varied from monthly to daily in thc 7 patients. Thrce of the 7 patients undcrwent surgical resection of the fronial lobe, and 2 of the 3 became frce of the intractable scizures. lnterictal dischargc such as spikcs or sharp waves were localized at F3 in 2 patients and at F4 in 5 patients. Ictal discharge at the onset of a paltcrn in scalp EEG recordings in 2 pati waves wcre seen at the left frontal lobe in I bilaterally in patient. The ictal scalp EEG recordings of the remaining 3 patients were distorted by electromyographic and movement artifacts. Finally, it was determined that the ictal scalp EEG is not always helpful for the localization of the epileptogenic focus. MRI revcaled focal cortical dysplasia in 2 patients: in the right middle frontal gyrus in I, and left basolateral frontal lobe i n the other. Interictal ECD SPECT revealcd no hypoperfused area in any of the 7 paticnts. We obtained ictal ECD SPECT i n 4 paticnts in cooperation with colleagues who controlled the violent movements of the patient during a seizure. In all 4 cases, ictal ECD SPECT revealed hypcrperftision in the frontal lobe, in the left frontal area in 2 patients and the right frontal area in 2 patients. Three of the 4 patients had undergone epilepsy surgery. Thc 2 patients who had cortical dysplasia underwent cxcision of the lesion and had excellent seizure control. The remaining I paticnt who had no abnormal CT findings continued to have seizures wcckly even after resection of the right orbitofrontal cortex. Conclusions: It is difficult to localize the epileptogenic focuin cases of complex gcstural automatism. The diagnostic yield in our study was maximal with ictal ECD SPECT even though thc seizure pattern could not be diagnosed clearly due to interference by electromyographic waves. A combination of MRI and ictal ECD SPECT is the key to localization of the cpileptic focus in casc of FLE with complex gestural automatism.