EEG Characteristics of Full-Term Neonatal Seizures Confirmed by Electrical Seizure / 대한간질학회지

PURPOSE: Neonatal seizure is the most significant parameter of neurological insult, however its pathophysiology and diagnostic consensus is still controversial. We performed this study to investigate the characteristics of electroencephalogram (EEG) in neonatal seizures, to validate the efficacy of radiological studies, and to estimate the occurrence of further subsequent epileptic seizures. METHODS: Seventeen patients with full-term neonatal seizure confirmed by electrical seizure were enrolled. Mean birth weight is 3.29 kg, and mean duration of follow-up is 22.7 months. Medical records and EEG were retrospectively reviewed. RESULTS: Subtle seizure is the most common seizure type: subtle seizure in 6 (35%), subtle seizure with focal clonic seizure in 2(12%). In 12 patients (71%), abnormal background activities were observed, and trace discontinua is the most common abnormal finding. Ictal EEGs were mostly localized into unilateral posterior quadrant in 11 (64%), however, the remained were localized into the frontal area. Brain USG did not reveal any abnormal finding in 9 patients (53%), whereas brain MRI didn't in 4 patients (25%). Brain MRI found abnormal findings in 5 out of 9 patients with negative brain USG result. Subsequent epileptic seizures followed in 7 patients (44%). Conclusion: Background activity is still useful as an indirect marker of neonatal seizure. Different generation or propagation mechanism can be suggested in that ictal EEGs were often localized into the frontal area in minor portion. Brain MRI is more sensitive than brain USG, especially in case of cerebral infarct or hypoxic-ischemic encephalopathy.

Reflex seizures induced by micturition: A pediatric case and ictal EEG finding / 소아과

Reflex seizures induced by micturition are rare, and there have been few reports on ictal electroencephalogram (EEG) findings. Here, we report a 7-year-old boy with secondarily generalized partial seizures induced by micturition. The seizures occurred every time he urinated. A few seconds after micturition begun, he toppled down with hand automatism followed by a secondarily generalized tonic posture and loss of consciousness. Ictal video-EEG recording during urination was performed. An ictal EEG demonstrated a polyspike wave discharge onset from the left frontotemporal region, with rapid spread to the right frontotemporal region. He was treated with the antiepileptic drug valproate sodium, which improved seizure control. He remained seizure-free until the last followup for a period of 2 years.

Intracranial Ictal EEG Patterns Predicting the Surgical Outcome and the Yield of Intracranial Electrodes in Patients with Temporal Lobectomy

BACKGROUND: Analysis of intracranial ictal patterns may help to predict surgical outcomes. We investigated intracranial EEG patterns to correlate with surgical outcomes and compared the yield of 'subdural electrodes alone (SE)' versus 'combined depth and subdural electrodes (CDSE)' for ictal lateralization in temporal lobe epilepsy (TLE). METHODS: We reviewed a total of 95 seizures recorded by bilateral temporal depth and subdural electrodes in 25 TLE patients who underwent surgery. We classified surgical outcomes as 'seizure-free' or 'not-seizure-free'. Each seizure was analyzed based on the presence or absence of peri-ictal discharges, ictal distribution, waveform patterns, onset frequency and involved number of electrodes, and interhemispheric propagation time (IHPT). The accuracy of lateralizing seizure foci by CDSE was compared to that by SE. RESULTS: 20 patients (80.0%) were 'seizure-free' and 5 (20.0%) were 'not-seizure-free'. The presence of peri-ictal discharges (p<0.001), distribution of depth only or depth and medial electrodes (p<0.001) and higher onset frequency (p=0.021) were associated with 'seizure-free' outcomes. Ictal onset pattern with fast spike trains was common in 'seizure-free', whereas pattern with rhythmic activity was common in 'not-seizure-free' (p=0.005). SE correctly lateralized in 18 of 20 patients, and incorrectly lateralized in the remaining 2 patients, but CDSE correctly lateralized in all 20 patients. CONCLUSIONS: Some intracranial ictal patterns were significantly correlated with good surgical outcomes. These findings suggest that the analysis of ictal EEG patterns help to predict surgical outcomes. CDSE is more accurate for the lateralization of seizure foci compared to SE.

Comparison of Cheek Electrode with Sphenoidal Electrodes for Identification of Ictal Onset Activity

BACKGROUND: The sphenoidal electrodes are used to localize epileptiform discharge in temporal lobe epilepsy. However, the insertion of the sphenoidal electrodes is a semi-invasive procedure that is painful and uncomfortable. The sensitivity of sphenoidal electrodes varies depending on the tip position of the wire electrode. We investigated the usefulness of cheek electrodes for the identification of the ictal onset activity in temporal lobe epilepsy, and then compared it with that of sphenoidal electrodes. METHODS: Both the cheek electrodes and the sphenoidal electrodes were positioned and seizure monitoring was performed on 17 patients suffering from complex partial seizures. Remontaging the EEG using the sphenoidal and cheek electrodes produced EEG printouts for each seizure, alternatively. Two neurologists interpreted all of the records independently. The EEGs were used to lateralize and localize the ictal onset activity and time of onset of ictal activity. RESULTS: There were a total of 95 seizures in the 17 patients. The overall amplitude recorded by cheek electrodes was slightly lower than sphenoidal electrodes. But there were no significant differences between these two types of electrodes in detection of ictal onset. CONCLUSIONS: The cheek electrodes are comparable with the sphenoidal electrodes in its effectiveness for the localization of ictal activity in patients with complex partial seizures. It is a relatively comfortable technique. It may replace sphenoidal electrodes for the identification of ictal onset activity in complex partial seizures.

A Case of Status Epilepticus Amauroticus / 대한간질학회지

Ictal blindness is a deficient symptomatology of partial seizure arising from visual cortex and usually short lived. When the blindness is the initial semiology of seizures, epileptic discharge arising from the primary visual cortex is associated. Ictal blindness has been reported in many patients with occipital lobe epilepsy, but prolonged ictal blindness called status epilepticus amauroticus has been reported only in few patients. We report a 45-year-old woman who had suffered prolonged epileptic blindness. The epileptic blindness was accompanied with rapid eyelid blinking and upward turning of head and eyeballs. Motor seizure and mental changes were not occurred. Ictal EEG showed 11-13 Hz repetitive spikes on the right occipital area followed by propagation to ipsilateral temporal area and contralateral occipital area. On T2-weighted MRI, abnormal lesions with high signal intensity were noted within bilateral occipital areas. She had been improved dramatically by loading dose of intravenous phenytoin.

Usefulness of Sphenoidal Electrodes for Localization of Temporal Lobe Seizure Focus : Ictal EEG / 대한간질학회지

PURPOSE: Usefulness of sphenoidal electrodes for detecting mesial temporal seizure foci remains controversial. Our aim is to determine whether sphenoidal electrodes are superior to surface electrodes for EEG localization in patients with mesial temporal lobe epilepsy (TLE). METHODS: We retrospectively reviewed ictal EEGs recorded simultaneously with standard International 10-20 System, subtemporal and sphenoidal electrodes in 92 patients who underwent temporal lobectomy. Patients were divided into mesial (n=67) and neocortical (n=25) TLE. Ictal EEGs were reviewed in a blinded fashion in both longitudinal bipolar and Pz referential montages. RESULTS: Thirty four (13.1%) of 259 mesial temporal seizures were exclusively isolated to sphenoidal electrode at least 3 seconds before involvement of subtemporal electrodes or were localized to temporal lobe on sphenoidal electrode when scalp electrode failed to localize seizure onset, whereas only 2 (2.6%) of 75 neocortical temporal seizures were (p<0.05). The usefulness of sphenoidal electrode was related to the distribution but not the frequency of ictal onset on scalp EEG. CONCLUSIONS: Although isolated or localized sphenoidal seizure onset in patients with mesial TLE are not frequent, sphenoidal electrodes are superior to scalp electrodes for the localization of mesial temporal seizure foci.

Intracranial Ictal Electroencephalographic Patterns in Parietal Lobe Epileptic Seizures : Correlation with Surgical Outcome

BACKGROUNDS: Parietal lobe epilepsy is uncommon and its intracranial ictal EEG findings have not been well elucidated. We investigated the ictal EEG patterns of epilepsy originating from the parietal lobe and its adjacent areas recorded by intracranial subdural electrode arrays. METHODS: The following intracranial ictal EEG patterns from twenty patients who underwent epilepsy surgery for medically intractable parietal lobe epilepsy were studied: 1) Anatomical ictal onset area [pure parietal (PP), combined parietal and extraparietal, such as fronto-parietal, temporo-parietal, etc. (EP)], 2) localization within the parietal lobe, 3) extent of the ictal onset zone, 4) the number of ictal onset zones, 5) frequency and waveform of ictal onset rhythms, and 6) type of spreading. RESULTS: Twelve patients (60%) were seizure-free (5 from PP, 7 from EP) and 8 were with persistent seizures (3 from PP, 5 from EP). Eight patients (40%) had ictal onset from PP and 12 were from EP. There were! Significant correlations with surgical outcome (p<0.05) in two variables: extent of ictal onset zone and type of spread. Patients with focal onset zones (n=9) showed better outcomes (eight are seizure-free) than those with wide ictal onset zones (4 out of 7 are seizure-free). Patients with slow spreading patterns showed better outcomes (12 from 16 are seizure-free) than those with fast spreading outcomes (all of them had persistent seizures). CONCLUSIONS: The extent of ictal onset zones correlates with surgical outcomes. The patterns of intracranial ictal EEG are helpful in predicting the surgical outcomes for parietal lobe epilepsy. (J Korean Neurol Assoc 19(5):478~484, 2001)

Differentiation of Temporal Lobe Epilepsy by Scalp Ictal EEG and Its Correlation with Surgical Outcome / 대한간질학회지

PURPOSE: Ebersole and Pacia recently introduced a classification of scalp ictal EEG in temporal lobe epilepsy (TLE). So we investigated whether scalp ictal EEG without sphenoidal electrode can differentiate mesial TLE from neocortical TLE and can be predictive of surgical outcome after temporal lobectomy. METHODS: A consecutive 77 patients (male 43, female 34) with TLE were included who had temporal lobectomy after the comprehensive presurgical evaluation. The patients with mesial TLE were 59 and those with neocortical TLE 18. The total 358 seizures were analyzed using bipolar and monopolar montage without sphenoidal electrodes. Scalp ictal EEGs were categorized into 3 types based on Ebersole and Pacia's classification and then were evaluated with regard to the differentiation of TLE and its correlation with surgical outcome. RESULTS: 1) Out of the total 77 patients, type 1 pattern was observed in 23 (30%), type 2 in 51 (65%), and type 3 in 3 (5%). The number of patients with mesial TLE were 17 (74%) out of 23 with type 1, 41 (80%) out of 51 with type 2, 1 out of 3 with type 3. Type 1 pattern was relatively specific (74%) but not sensitive (30%) for mesial TLE. Also the lesion location of neocortical TLE with type 1 onset was not limited to medial temporal area. 2) Scalp ictal EEG patterns were significantly correlated with surgical outcome only in the subgroup of mesial TLE (p=0.006) but not in neocortical TLE. Type 1 onset pattern in mesial TLE was associated with favorable outcome comparing to type 2 onset. CONCLUSIONS: Scalp ictal EEG onset pattern cannot accurately differentiate mesial TLE from neocortical TLE. However, its onset pattern can be predictive of surgical outcome.

Nonconvulsive Status Epilepticus of Frontal Origin: 2 Cases

Nonconvulsive status epilepticus (NCSE) of frontal origin is rare. The symptoms are unusual and different from that of temporal origin which makes it difficult to be diagnosed. We report two cases with NCSE of frontal origin. The first case was a 17-year-old girl who presented indifference and reduced word fluency, responsiveness, and facial expres-sion daylong with intermittent unresponsiveness and slight rightward eye and head deviations. Confusion was not noted. Electroencephalogram (EEG) showed the recurrent 2 Hz spike-wave ictal discharges on the left frontal area, sometimes spreading to the opposite side. The second case was a 57-year-old woman who had a medically intractable epilepsy. During long-term Video/EEG monitoring, the continuous 2 Hz spike-and-wave complexes were noted on the right hemisphere and the left frontal area. At that time, neurological examination including cognitive functions was normal except for a mild jaw tremor. No confusion was noted. However, she looked depressed, inactive, and affectively indifferent. Intravenous lorazepam injection abolished status EEG activities as well as clinical symptoms. Ictal single photon emission computed tomography (SPECT) showed an increased perfusion in the right frontal lobe. Cortical dysplasia was pathologically diagnosed after a right frontal lobectomy.