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Abstracts of Poster Presentations / Clinical Neurophysiology 125, Supplement 1 (2014) S1–S339
defined as harmonic driving lasting after the cessation of the flash, in patients with epilepsy? Subjects: Three-hundred and seventy-one patients with epilepsy (194 males), age 37±15 years old (mean ± SD), who visited epilepsy clinic and were recorded electroencephalography (EEG) with photic stimulation, were included. Controls subjects were 6 males and 5 females, age 36±13 years old. Methods: EEG was recorded with scalp electrodes set in International 10-20 system. Photic stimulation was performed by placing the stroboscope in front of the subjects’ eyes which were closed. The frequencies of repetitive photic stimulations were 3, 6, 8, 10, 12, 14, 16, 18, and 20 Hz, each delivered for 10 sec with the pause of 10 sec. Results: Sustained photic driving was notices in 31% of patients with epilepsy and 91% of normal controls. Duration of sustained photic driving was significantly longer in patients with epilepsy (243±59 ms in patients, 161±35ms in controls, p<0.005). By epilepsy classification, the duration was significantly longer in partial epilepsies (frontal lobe epilepsy, temporal lobe epilepsy, and parietal lobe epilepsy) and idiopathic generalized epilepsy than in normal controls (p<0.005). Conclusions: Sustained photic driving is a physiological phenomenon seen in normal subjects. Rarer occurrence or longer duration in patients with epilepsy may associate with their abnormality in synchronization or desynchronization.
P791 A case of temporal lobe epilepsy with sudden diarrhea T. Murai 1 , T. Tohyama 2 , M. Kinoshita 3 1 Kyoto City Hospital, Neurology, Kyoto, Japan; 2 Kyoto Min-iren Chuo Hospital, Psychiatry, Kyoto, Japan; 3 Utano National Hospital, Neurology, Kyoto, Japan Question: Can temporal lobe epilepsy manifest with repeated episodes of sudden diarrhea and loss of consciousness? Methods: A 63-year-old right-handed female presented with chief complaints of sudden diarrhea and loss of consciousness for almost three decades. The first attack occurred in her 30s and similar attacks repeated several times in a year. Her attacks comprised of abrupt abdominal discomfort, diarrhea, sudden emergence of old memories that she had played with her brother in her childhood, and loss of consciousness during defecation. She had no convulsion or automatism and fully recovered in a few minutes. Every time she was transferred to emergency hospital by ambulance, she had examinations such as blood test, head computed tomography, electrocardiogram, abdominal ultrasound, and electroencephalography (EEG), but no specific diagnosis was made. She was admitted to our hospital for further evaluation of epilepsy. Results: Vital signs, neurological examination, and blood tests showed no abnormal finding. During long-term video-EEG monitoring for forty hours she had no habitual event. Interictal EEG showed intermittent irregular delta waves and sharp transients regional left anterio-midtemporal area. Sharp transients were not as outstanding from background activities as to be definite epileptiform discharges, but they were reproducible in morphology and distribution, and appeared not only in sleep but also in awake. Brain magnetic resonance imaging was unremarkable. Brain Single photon emission computed tomography showed decrease of blood flow in left frontal and temporal lobes. Wechsler Adult Intelligence Scale-III showed decline of verbal comprehension. We diagnosed that the patient was suffering from partial epilepsy originating from left temporal lobe. Carbamazepin markedly improved her attacks. Conclusions: Temporal lobe epilepsy can manifest with diverse autonomic symptoms and signs. Abdominal sensations often herald the onset of epileptic seizures. Among them is an uncommon syndrome called abdominal epilepsy, in which gastrointestinal complaints are the primary or the sole manifestation of epileptic seizures. In patients who complain with diarrhea and other autonomic symptoms otherwise unexplained, a possible diagnosis of epilepsy should be considered.
(DTI) and Diffusion Tensor Tractography (DTT) in identifying abnormalities in MRI negative patients with cryptogenic extramesiotemporal focal epilepsies. Methods: 14 patients with cryptogenic extramesiotemporal focal epilepsy were investigated. DTI data was acquired on a GE Signa HDx 3T Scanner, using an acquisition scheme with 64 diffusion weighted directions, a bvalue of 1000m/s2 , 2.4 mm slice thickness and 2 mm in-plane resolution. Fractional anisotropy (FA) maps were investigated for focal changes and asymmetries. Streamline DTT of the whole brain was used as an exploratory method in the absence of a structural lesion and the number of reconstructed streamlines in homologous anatomical areas of the left and right hemisphere were compared. Asymmetries of more than 10% for FA maps and more than 20% for the streamline count were rated as a significant finding. Results: Asymmetries in the number of reconstructed streamlines were found in nine of the 14 patients (64%). In eight of them, these changes were consistent with the clinically suspected seizure onset zone, based on video-EEG-monitoring and nuclear medicine data, however, in two patients DTT indicated more widespread, hemispheric changes, beyond the seizure onset zone. FA maps show asymmetries beyond 10% in only one patient. In two patients, the seizure onset zone was confirmed in the area of DTT abnormalities by intracranial electrodes, the other patients are still awaiting invasive evaluation, including the one with discrepant DTI findings. Conclusions: These preliminary data show the potential role of DTI and DTT as complementary lateralizing and localizing imaging modality in the presurgical evaluation of cryptogenic extramesiotemporal epilepsy patients. We hypothesize, the observed changes reflect migration disorders, where heterotopic neurons disrupt the microstructural order of white matter underlying the seizure onset zone. Follow ups with intracranial electrodes and correlation with histopathology are required for further interpretation of these findings. DTT appears to be more sensitive than FA maps, and this method may be less sensitive in patients with small circumscribed focal pathologies compared to patients with a more widespread pathology.
P793 Consistency over time of electroencephalographic connectivity measures in temporal lobe epilepsy Y. Höller 1,2 , K. Butz 1 , A. Thomschewski 1,2 , P. Hoeller 1,2 , E. Trinka 1,2 Paracelsus Medizinische Privatuniversitaet, Universitaetsklinik fuer Neurologie, Salzburg, Austria; 2 Paracelsus Medizinische Privatuniversitaet, Spinal Cord Injury and Tissue Regeneration Center, Salzburg, Austria
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Objective: Connectivity biomarkers of the EEG have been shown to reflect seizure propagation and to indicate the source of abnormal hyperconnectivity. Nevertheless, it is questionable if these patterns are stable over time
P792 Diffusion tensor imaging and tractography identify structural changes in cryptogenic focal epilepsy J. Goc, E. Hartl, C. Catarino, A.-M. Loesch, J. Remi, S. Noachtar, C. Vollmar University of Munich, Munich, Germany Question: Here we investigate the contribution of Diffusion Tensor Imaging
Figure 1. GGC consistency for patients with right-lateralized TLE. x-axis: 2-40Hz; yaxis: correlations −1 to +1; green: not significant; red: significant correlations (FDRcorrected p<0.00004).