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PS-28-7 Dipole patterns of interictal epileptiform discharges on routine EEG recording
Postersesston 28. Epilepsy (1)
IPS-28-71
Dipole patterns of interictal eplleptlform discharges on routine EEG recording
Yew-Long Lo, Shih-Hui Lim 1, Winston Lim, Meng-Cheong Wong. Department of Neurology, SGH Brain
Centre, Singapore; 1Department of Diagnostic Radiology, Singapore General Hospital, Singapore
S155
tients, whose causes could not be determined, 2 had the pathological evidence of meningitis. [Conclusion] Although meningitis/encephalitis (suspicion) was the most frequent estimated cause, Meningitis was pathologically proved at a lower frequency, and age-related changes were thought to be a cause. The incidence of MTS was high in intractable cases. AHS was often observed, other than brain tumors.
Objectives: To examine routine EEGs of patients with interictal epileptiform discharges (IEDs), for the presence of dipoles, and whether these dipoles correlate with temporal vs. extratemporal focality. Background."The presence of dipoles (detected using sphenoidal electrodes and non-cephalic reference during long term E E G monitoring) amongst patients with temporal IEDs is associated with mesial temporal sclerosis (MTS). However, the presence of dipoles in routine E E G recordings has not received much study. Methods: EEGs of patients with clearcut focal, unilateral IEDs were retrospectively analyzed. EEGs were recorded digitally using scalp (with T1 & T2), without sphenoidal electrodes, under routine conditions. Presence and distribution of dipole were determined using different references including contralateral ear and scalp electrodes furthest from the IEDs. MRI scans were reviewed for the presence of MTS. Findings: All 17 patients with unilateral temporal IEDs and 87/159 (55%) of their IEDs examined showed the presence of a dipole. Negative pole was maximum over anterior temporal electrodes. Positive pole was maximum over the contralateral centro-parietal region. Of 13 patients with extratemporal IEDS and their 134 unilateral extratemporal IEDS, none showed the presence of dipole (p < 0.000001). MTS was present in 9 of 11 (82%) patients with unilateral temporal IEDs examined by MRI. Only I of 5 (20%) patients with unilateral extra-temporal IEDs had MTS. Conclusions: Dipoles can be detected in routine EEGs without using sphenoidal electrodes and noncephalic references. Their presence correlates with unilateral temporal IEDs, and suggests underlying MTS.
[ PS-28-81 Relationship between imaging and pathological features and clinical factors in surgical cases of temporal lobe epilepsy Hideji Uesugi, Hiroyuki Shimizu 2, Masaya Oda 3, Hiroshi Matsuda 1, Nobutaka Arai 3, Hiroshi Nakayama 3, Takeyoshi Maehara 2. Department of Psychiatry, Japan;
1Department of Radiology, National Hospital for Mental, Nervous and Muscular Disorders, Japan; 2Department of Neurosurgery, Japan; 3Department of Pathology, Tokyo Metropolitan Neurological Hospital, Japan Sixty-two patients who had no attacks after surgery were used as subjects. The mean age at surgery was 28.9 -t- 10.1 years. MR images (3 mm slice) and SPECT (PET) were performed. [Results] (1) On MRI, mesial temporal sclerosis (MTS) was detected in 48 of 52 patients (92%); 32 (62%) had high-signal intensity on T2-weighted images; 31 (60%) had atrophy; 5 had calcified lesions; 2 had cystic lesions. On SPECT, abnormal cerebral blood flow was noted in 33 of 36 patients (92%). (2) On pathological observation, Ammon's horn sclerosis (AHS), tumors, and gliosis in lateral temporal were detected in 43, 10, and 6, respectively, whereas 2 showed no abnormalities. MRI were abnormal in 35 of 36 AHS patients (97%). The 2 patients with normal pathology showed both high-signal intensity and atrophy on MRI. (3) Diseases estimated to be causes of TLE were meningitis/encephalitis (or suspicion of these diseases) in 24 patients (39%), injuries at birth in 5, and none in 33. Of the 24 patients estimated to have meningitis/encephalitis as a cause, only 6 had the pathological evidence of meningitis. Of the 33 pa-
] PS-28-9 ] Clinical outcome of surgical resection of the lesion identified by MRI for refractory epilepsy Kouzo Moritake 1, Yoshifumi Matsumoto 1, Junko Hatta 1, Haruhiko Kikuchi z. l Department ofNeurosurgery, Shimane
Medical University, Japan; 2 Kyoto UniversityMedical School, Japan Soon after its introduction, we have developed a protocol for the surgical treatment of epilepsy which uses MRI as the primary diagnostic tool for identifying the lesion to be resected. Whether or not a lesion identified by MRI is an epileptogenic focus is determined by non-invasive method, including ictal E E G analysis with sphenoid electrodes. If epileptogenesis confirmed, we proceed to craniotomy. We localize the lesion intraoperatively, and use electrophysiologic and hemodynamic studies to confirm that we have the true source of the seizures. Resective surgery was undertaken in 37 cases. Their age at surgery ranges from 2 to 51 (mean 18) years, and duration of their seizure disorder was from one to 41 (mean 10) years. Dominant site of the brain resection was not temporal but extratemporal. Major pathological findings of resected specimens were gliotic and hamartomatous lesions. In both temporal and extratemporal resection groups, clinical outcome was excellent in about 60% and good in 30% of surgical cases. Postoperatively no patient suffered permanent neurological deficit or complication. MRI is considered to contribute to extending indication of the surgical treatment of epilepsy and improving its clinical outcome, especially in extratemporal resective surgery.
I PS-28-i 01 Photoparoxysmal responses in patients with video game induced seizures Masahisa Satoh 1, Takeo Takahashi 2. l Department of Pediatrics, Niigata City General Hospital, Japan; 2 Yaotome Clinic, Sendai, Japan Over the past 5 years, we have experienced 21 patients (M/F = 17/4, mean age 13 years) who had seizure(s) while playing TV games. Of 21 patients, 16 were epileptics and 5 were diagnosed as situationrelated seizure. By using 15 and 20 Hz flicker frequencies, we performed the following E E G activation: visual stimuli of (1) stroboscopic white flicker, (2) red flicker, (3) flickering dot pattern, and (4) flickering grating pattern. To obtain visual stimuli of (2) to (4), we utilized stroboflickers of R-21, DU-22, and GO-22, respectively, made by Nihon Kohden. A stroboscopic white flicker stimulation was ineffective, whereas those of(2) to (4) elicited generalized photoparoxysmal responses (PPRs) in 9 patients (41.3%); a red flicker stimulation elicited PPRs in 7 patients (33%); a flickering dot pattern stimulation elicited PPRs in 3 patients (15%); a flickering grating pattern stimulation elicited PPRs in 2 patients (10%). These results suggest that visual stimuli of red flicker and flickering geometric patterns may be useful in E E G diagnosis of video game induced seizures.
IPS-28-71
Dipole patterns of interictal eplleptlform discharges on routine EEG recording
Yew-Long Lo, Shih-Hui Lim 1, Winston Lim, Meng-Cheong Wong. Department of Neurology, SGH Brain
Centre, Singapore; 1Department of Diagnostic Radiology, Singapore General Hospital, Singapore
S155
tients, whose causes could not be determined, 2 had the pathological evidence of meningitis. [Conclusion] Although meningitis/encephalitis (suspicion) was the most frequent estimated cause, Meningitis was pathologically proved at a lower frequency, and age-related changes were thought to be a cause. The incidence of MTS was high in intractable cases. AHS was often observed, other than brain tumors.
Objectives: To examine routine EEGs of patients with interictal epileptiform discharges (IEDs), for the presence of dipoles, and whether these dipoles correlate with temporal vs. extratemporal focality. Background."The presence of dipoles (detected using sphenoidal electrodes and non-cephalic reference during long term E E G monitoring) amongst patients with temporal IEDs is associated with mesial temporal sclerosis (MTS). However, the presence of dipoles in routine E E G recordings has not received much study. Methods: EEGs of patients with clearcut focal, unilateral IEDs were retrospectively analyzed. EEGs were recorded digitally using scalp (with T1 & T2), without sphenoidal electrodes, under routine conditions. Presence and distribution of dipole were determined using different references including contralateral ear and scalp electrodes furthest from the IEDs. MRI scans were reviewed for the presence of MTS. Findings: All 17 patients with unilateral temporal IEDs and 87/159 (55%) of their IEDs examined showed the presence of a dipole. Negative pole was maximum over anterior temporal electrodes. Positive pole was maximum over the contralateral centro-parietal region. Of 13 patients with extratemporal IEDS and their 134 unilateral extratemporal IEDS, none showed the presence of dipole (p < 0.000001). MTS was present in 9 of 11 (82%) patients with unilateral temporal IEDs examined by MRI. Only I of 5 (20%) patients with unilateral extra-temporal IEDs had MTS. Conclusions: Dipoles can be detected in routine EEGs without using sphenoidal electrodes and noncephalic references. Their presence correlates with unilateral temporal IEDs, and suggests underlying MTS.
[ PS-28-81 Relationship between imaging and pathological features and clinical factors in surgical cases of temporal lobe epilepsy Hideji Uesugi, Hiroyuki Shimizu 2, Masaya Oda 3, Hiroshi Matsuda 1, Nobutaka Arai 3, Hiroshi Nakayama 3, Takeyoshi Maehara 2. Department of Psychiatry, Japan;
1Department of Radiology, National Hospital for Mental, Nervous and Muscular Disorders, Japan; 2Department of Neurosurgery, Japan; 3Department of Pathology, Tokyo Metropolitan Neurological Hospital, Japan Sixty-two patients who had no attacks after surgery were used as subjects. The mean age at surgery was 28.9 -t- 10.1 years. MR images (3 mm slice) and SPECT (PET) were performed. [Results] (1) On MRI, mesial temporal sclerosis (MTS) was detected in 48 of 52 patients (92%); 32 (62%) had high-signal intensity on T2-weighted images; 31 (60%) had atrophy; 5 had calcified lesions; 2 had cystic lesions. On SPECT, abnormal cerebral blood flow was noted in 33 of 36 patients (92%). (2) On pathological observation, Ammon's horn sclerosis (AHS), tumors, and gliosis in lateral temporal were detected in 43, 10, and 6, respectively, whereas 2 showed no abnormalities. MRI were abnormal in 35 of 36 AHS patients (97%). The 2 patients with normal pathology showed both high-signal intensity and atrophy on MRI. (3) Diseases estimated to be causes of TLE were meningitis/encephalitis (or suspicion of these diseases) in 24 patients (39%), injuries at birth in 5, and none in 33. Of the 24 patients estimated to have meningitis/encephalitis as a cause, only 6 had the pathological evidence of meningitis. Of the 33 pa-
] PS-28-9 ] Clinical outcome of surgical resection of the lesion identified by MRI for refractory epilepsy Kouzo Moritake 1, Yoshifumi Matsumoto 1, Junko Hatta 1, Haruhiko Kikuchi z. l Department ofNeurosurgery, Shimane
Medical University, Japan; 2 Kyoto UniversityMedical School, Japan Soon after its introduction, we have developed a protocol for the surgical treatment of epilepsy which uses MRI as the primary diagnostic tool for identifying the lesion to be resected. Whether or not a lesion identified by MRI is an epileptogenic focus is determined by non-invasive method, including ictal E E G analysis with sphenoid electrodes. If epileptogenesis confirmed, we proceed to craniotomy. We localize the lesion intraoperatively, and use electrophysiologic and hemodynamic studies to confirm that we have the true source of the seizures. Resective surgery was undertaken in 37 cases. Their age at surgery ranges from 2 to 51 (mean 18) years, and duration of their seizure disorder was from one to 41 (mean 10) years. Dominant site of the brain resection was not temporal but extratemporal. Major pathological findings of resected specimens were gliotic and hamartomatous lesions. In both temporal and extratemporal resection groups, clinical outcome was excellent in about 60% and good in 30% of surgical cases. Postoperatively no patient suffered permanent neurological deficit or complication. MRI is considered to contribute to extending indication of the surgical treatment of epilepsy and improving its clinical outcome, especially in extratemporal resective surgery.
I PS-28-i 01 Photoparoxysmal responses in patients with video game induced seizures Masahisa Satoh 1, Takeo Takahashi 2. l Department of Pediatrics, Niigata City General Hospital, Japan; 2 Yaotome Clinic, Sendai, Japan Over the past 5 years, we have experienced 21 patients (M/F = 17/4, mean age 13 years) who had seizure(s) while playing TV games. Of 21 patients, 16 were epileptics and 5 were diagnosed as situationrelated seizure. By using 15 and 20 Hz flicker frequencies, we performed the following E E G activation: visual stimuli of (1) stroboscopic white flicker, (2) red flicker, (3) flickering dot pattern, and (4) flickering grating pattern. To obtain visual stimuli of (2) to (4), we utilized stroboflickers of R-21, DU-22, and GO-22, respectively, made by Nihon Kohden. A stroboscopic white flicker stimulation was ineffective, whereas those of(2) to (4) elicited generalized photoparoxysmal responses (PPRs) in 9 patients (41.3%); a red flicker stimulation elicited PPRs in 7 patients (33%); a flickering dot pattern stimulation elicited PPRs in 3 patients (15%); a flickering grating pattern stimulation elicited PPRs in 2 patients (10%). These results suggest that visual stimuli of red flicker and flickering geometric patterns may be useful in E E G diagnosis of video game induced seizures.