The role of the intracarotid amobarbital procedure in evaluation of patients for epilepsy surgery.

PURPOSE: To examine the role of the intracarotid amobarbital procedure (IAP) in the presurgical evaluation of patients with medically refractory localization-related epilepsy. METHODS: We retrospectively studied 111 patients who underwent cortical resective surgery at our center between 1991 and 1996. In patients with mesial temporal lobe epilepsy (mTLE), a presurgical determination of the epileptogenic zone was compared with localization based on IAP memory asymmetry scores, and with ultimate localization after resective surgery. In patients with neocortical or mesial frontal epilepsy, the IAP was evaluated for evidence of unilateral or bilateral poor memory performance. RESULTS: Of 68 patients with mTLE localized by noninvasive tests, 60 had concordant lateralized memory deficits on IAP. Eight patients had lateralized memory deficits on IAP that were discordant with noninvasive tests and with localization as determined by surgical outcome. All 11 mTLE patients requiring invasive EEG monitoring were correctly lateralized by IAP, including one patient in whom the noninvasive evaluation otherwise provided false lateralization. Of 32 patients with neocortical or mesial frontal lobe epilepsy, 21 displayed memory deficits on IAP. Of 10 patients with bilateral deficits, five had mesial frontal lobe epilepsy. In 13 patients with lateralized memory deficits, seven underwent electrode implantation in the mesial temporal lobe, and four ultimately underwent resection of an epileptogenic mesial temporal lobe in addition to a neocortical resection. CONCLUSIONS: In patients with mTLE, lateralized memory deficits on IAP usually confirm localization provided by noninvasive tests. However, in mTLE not well lateralized by the noninvasive evaluation, and in neocortical or mesial frontal epilepsy, the IAP may provide information regarding localization that ultimately alters surgical management.

Ictal semiology in hippocampal versus extrahippocampal temporal lobe epilepsy.

We have analysed retrospectively the clinical features and electroencephalograms in 35 patients with complex partial seizures of temporal lobe origin who were seizure-free after epilepsy surgery. Two groups were differentiated for statistical analysis: 16 patients had hippocampal temporal lobe seizures (HTS) and 19 patients had extrahippocampal temporal lobe seizures (ETS) associated with a small tumour of the lateral or inferior temporal cortex. All patients in the HTS group had ictal onset verified with intracranial recordings (depth or subdural electrodes). In the ETS group, extrahippocampal onset was verified with intracranial recordings in eight patients and assumed, because of failure of a previous amygdalohippocampectomy, in one patient. Historical information, ictal semiology and ictal EEG of typical seizures were analysed in each patient. The occurrence of early and late oral automatisms and dystonic posturing of an upper extremity was analysed separately. A prior history of febrile convulsions was obtained in 13 HTS patients (81.3%) but in none with ETS (P < 0.0001, Fisher's exact test). An epigastric aura preceded seizures in five patients with HTS (31.3%) and none with ETS (P = 0.0135, Fisher's exact test), while an aura with experiential content was recalled by nine patients with ETS (47.4%) and none with HTS (P = 0.0015), Fisher's exact test). Early oral automatisms occurred in 11 patients with HTS (68.8%) and in two with ETS (10.5%) (P = 0.0005, Fisher's exact test). Early motor involvement of the contralateral upper extremity without oral automatisms occurred in three patients with HTS (18.8%) and in 10 with ETS (52.6%) (P = 0.0298, Fisher's exact test). Arrest reaction, vocalization, speech, facial grimace, postictal cough, late oral automatisms and late motor involvement of the contralateral arm and hand occurred with similar frequency in both groups. These observations show that the early clinical features of HTS and ETS are different.

Intracranial ictal recordings in Mesial frontal lobe epilepsy.

Localization of ictal onset in patients with medically refractory frontal lobe epilepsy is challenging even with intracranial monitoring. We present a series of nine patients with presumed mesial frontal lobe epilepsy in whom successful localization of ictal onset was achieved in most cases. Intracranial electrodes were placed over cingulate and supplementary motor cortex bilaterally, with additional electrodes placed over lateral and inferior frontal lobes as part of an evaluation for epilepsy surgery. Localization of the ictal onset was clearly defined in seven of nine patients and was characterized by a pattern of lower amplitude beta/gamma range frequencies noted in one to four adjacent electrodes arising from cingulate cortex or supplementary motor cortex in six patients. In the remaining patient, ictal onset was characterized by periodic high amplitude spike and slow-wave discharges evolving into a higher voltage faster rhythm. Electrographic onset occurred coincident with or preceded clinical findings. Ictal pattern also did not demonstrate a widespread propagation pattern in most of the recordings in which ictal onset was well localized. Precise localization of ictal onset within the mesial frontal lobe is possible. Rapid propagation to regions within and outside the frontal lobe does not always occur.

Adolescents with active or inactive epilepsy or asthma: a comparison of quality of life.

PURPOSE: We compared quality of life (QOL) in youth with inactive or active epilepsy with that of a similar sample of youth with asthma. We explored 19 different dimensions in three domains (psychological, social, and school) and also determined differences related to illness severity and gender. METHODS: Subjects were 228 adolescents (117 with epilepsy and 111 with asthma). Data were collected from clinic records and from the adolescents, their mothers, and their teachers through questionnaires and structured interviews. Data were analyzed by analysis of covariance. RESULTS: The analysis with all 19 QOL variables indicated a significant difference between the total asthma and the total epilepsy samples (multivariate F = 3.36, p = 0.0001). Further evaluation reflected differences between the epilepsy group and the asthma group on 13 of the 19 QOL variables. When active and inactive epilepsy and asthma groups were compared, youth with active epilepsy were faring worse than all other groups in 10 areas. Moreover, youth with inactive epilepsy were faring worse than those with inactive asthma in four areas. Illness severity and sex differences were more strongly related to QOL in the epilepsy sample than in the asthma sample. Sex-severity interactions suggested that girls with high seizure severity were most at risk for QOL problems. CONCLUSIONS: Youth with active epilepsy generally had the poorest QOL. Severe seizures and female sex were associated with more problems. Sex-severity interactions should be explored in future research.

Intracranial electrophysiologic studies.

The presurgical evaluation of patients with medically refractory epilepsy begins with a thorough noninvasive approach, including ictal monitoring with scalp recording technique. The concept of convergence of evidence is used to determine the adequacy of the noninvasive localization. A variety of intracranial electrophysiologic studies can be employed when the noninvasive evaluation is insufficient. Intracranial studies are used for precise identification of eloquent cortex. The ultimate lines of resection are then designed to include as much of the epileptogenic zone as possible, while excluding areas of eloquent cortical function.

Childhood epilepsy and asthma: comparison of quality of life.

We report results from the first data collection on an ongoing longitudinal study aimed at describing the natural history of adaptation to childhood epilepsy and asthma in children and their families. We studied 136 children with epilepsy and 134 children with asthma aged 8-12 years. Data were collected from the children, their mothers, and their school teachers through interviews, school records, and questionnaires. The two samples were compared on four domains of quality of life: physical, psychological, social, and school. Data were analyzed by a 2 x 2 between-subjects multivariate analysis of covariance with type of illness (epilepsy or asthma) as the independent variable and length of time since onset of illness as a covariate. A significant main effect was noted for illness [multivariate F (15, 236) = 11.36, p < 0.001]. Our major finding was that children with epilepsy had a relatively more compromised quality of life in the psychological, social, and school domains. In contrast, children with asthma had a more compromised quality of life in the physical domain. Our findings suggest that attention simply to seizure control in the clinical setting will not address the full range of quality-of-life problems of children with epilepsy.

Correlates of behavior problems in children with epilepsy.

We report results from the first part of an ongoing longitudinal study aimed at identifying the relative contributions of demographic, seizure, and family variables in the prediction of behavior problems in children with epilepsy. We studied 127 children with epilepsy aged 8-12 years and their mothers. Self-report questionnaires, interviews, and medical records were data sources. Backward and forward stepwise elimination procedures using multiple regression indicated five variables that contributed significantly to prediction of behavior problems: female gender, family stress, family mastery, extended family social support, and seizure frequency. These factors accounted for 29% (p < 0.001) of the variation in behavioral problems. Findings suggest that family variables are important correlates of behavior problems and should be considered in clinical management of children with epilepsy.

Interictal cerebral metabolism in partial epilepsies of neocortical origin.

We performed interictal [18F]fluorodeoxyglucose positron emission tomography (FDG PET) in 24 patients with partial epilepsy of neocortical origin. Two-thirds of patients had regions of hypometabolism. The zone of intracranially recorded electrographic ictal onset was always located in a region of hypometabolism, in those with hypometabolism. Hypometabolic regions in partial epilepsies of neocortical origin were usually associated with structural imaging abnormalities. Regional hypometabolism occasionally occurred without localizing ictal scalp EEG and cerebral magnetic resonance imaging findings, however. FDG PET may be useful in directing placement of intracranial electrodes for presurgical evaluation of refractory neocortical seizures.

Presurgical evaluation for partial epilepsy: relative contributions of chronic depth-electrode recordings versus FDG-PET and scalp-sphenoidal ictal EEG.

One hundred fifty-three patients with medically refractory partial epilepsy underwent chronic stereotactic depth-electrode EEG (SEEG) evaluations after being studied by positron emission tomography (PET) with 18F-fluorodeoxyglucose (FDG) and scalp-sphenoidal EEG telemetry. We carried out retrospective standardized reviews of local cerebral metabolism and scalp-sphenoidal ictal onsets to determine when SEEG recordings revealed additional useful information. FDG-PET localization was misleading in only 3 patients with temporal lobe SEEG ictal onsets for whom extratemporal or contralateral hypometabolism could be attributed to obvious nonepileptic structural defects. Two patients with predominantly temporal hypometabolism may have had frontal epileptogenic regions, but ultimate localization remains uncertain. Scalp-sphenoidal ictal onsets were misleading in 5 patients. For 37 patients with congruent focal scalp-sphenoidal ictal onsets and temporal hypometabolic zones, SEEG recordings never demonstrated extratemporal or contralateral epileptogenic regions; however, 3 of these patients had nondiagnostic SEEG evaluations. The results of subsequent subdural grid recordings indicated that at least 1 of these patients may have been denied beneficial surgery as a result of an equivocal SEEG evaluation. Weighing risks and benefits, it is concluded that anterior temporal lobectomy is justified without chronic intracranial recording when specific criteria for focal scalp-sphenoidal ictal EEG onsets are met, localized hypometabolism predominantly involves the same temporal lobe, and no other conflicting information has been obtained from additional tests of focal functional deficit, structural imaging, or seizure semiology.

Focal functional anatomy of dorsolateral frontocentral seizures.

We compared 6 patients with dorsolateral frontocentral seizures to 7 patients with temporal lobe seizures. We determined general seizure location by structural lesions in 7 patients, bilateral depth electrodes in 4, and EEG and semiology in 2. We then mapped seizure cortex and essential cortex using chronic ECoG arrays. Two ECoG patterns were similar in frontal and temporal seizures. Focal patterns were near lesions and resections. Regional patterns were distant from lesions but not associated with worse surgical outcome. "Dipolar" seizure patterns occurred in one-half of frontal patients with maps like somatosensory evoked responses, consistent with focal seizure anatomy and involvement of sensorimotor cortex. Dipole location estimates were near centers of seizure cortex determined by lesions, semiology, and outcome. Six temporal patients had focal excisions that gave significant seizure reduction in all. All frontocentral patients had focal excisions that significantly reduced seizures except in 1 patient with progressive disease. We conclude that dorsolateral frontocentral seizures have focal functional anatomy that can be predicted by ictal ECoG.

Ictal localization of temporal lobe seizures with scalp/sphenoidal recordings.

We assessed the reliability and accuracy of scalp/sphenodial recordings for ictal localization by retrospectively analyzing 706 noninvasive ictal recordings from 110 patients who subsequently underwent stereoencephalographic evaluation. Strictly defined unilateral temporal/sphenoidal ictal patterns correctly predicted findings of depth electrode examination in 82 to 94% of cases. These strictly defined predictive patterns could be detected with excellent interrater reliability. The patterns are misleading in only a minority of cases, but cannot be used in isolation for definite ictal localization.