Extratemporal Foci Research Articles

Cerebellar stimulation for seizure control: 17-year study.

Since 1974, 32 seizure patients have undergone chronic cerebellar stimulation (CCS); 27 have been contacted with 9 (7 spastic, 2 epileptic) continuing to use CCS for an average of 14.3 years (10-17 years). 6 (67%) are seizure-free and 3 (33%) have a reduction of seizure frequency. In the last 2 years, 2 other patients with spastic seizures, who were using CCS for 13 years, died of respiratory illness; 1 had been seizure-free and the other had a reduction. Of the remaining 16 patients (12 spastic, 4 epileptic) who did use CCS for an average of 8.3 years (2-14 years) and now have nonfunctioning stimulators, 5 (31%) continue to be seizure-free, 7 (44%) have a reduction and 4 (25%) have no change or a slight increase. Overall, 23 (85%) patients have benefitted from CCS. Stimulation charge densities were 0.9-2.5 microC/cm2/phase delivered at 10-180 pulses/sec to bilateral electrode pads on the superomedial cerebellar cortex. CCS is relatively safe and nonablative, and could be offered for patients with intractable seizures originating from bilateral or extratemporal foci.

Surgical treatment of epilepsy: our experiences with 34 children

Surgical treatment of medically intractable epileptic fits in children is highly specialized, owing to the specific etiology of epilepsies in this age group and the epileptogenic property of the brain in childhood. In our series of 340 patients operated on for medically intractable epileptic seizures, there were 34 (10%) patients up to 15 years of age (the youngest was 2 years old; mean age was 11 years). This group of patients comprises four subgroups: 9 patients with temporal foci, 6 patients with extratemporal foci, 16 patients with infantile hemiplegia and epilepsy, and 3 patients with epilepsia partialis continua (Kozhevnikov's disease). Preoperatively, detectable brain lesions were present in 30 (88%) cases, a much higher frequency than in adult surgical series. Postoperative follow-up so far is 1-14 years (mean, 4 years). Surgical outcome in this group of 34 patients is as follows: 21 (62%) are seizure-free, 8 (23%) have improved, and 5 (15%) have shown no improvement.

Comparison of bitemporal and unitemporal epilepsy defined by depth electroencephalography

Of 166 consecutive patients studied with depth electroencephalography (EEG), 87 had seizures arising from one temporal lobe and 23 had seizures arising independently from each temporal lobe. We retrospectively reviewed and compared those patients with unitemporal and those with bitemporal seizures. There was no statistically significant differences between the two groups in terms of age at onset of seizures, duration of epilepsy, localization of scalp EEG abnormalities, surgical results, or pathological findings. The bitemporal group, however, had significantly fewer patients with a history of febrile seizures (p less than 0.025). Two patients with bitemporal seizures were later found to have extratemporal lesions, and one an extrahippocampal temporal lesion, on magnetic resonance scans; one patient's extratemporal lesion was resected and all habitual seizures stopped. These findings suggest that a single pathophysiological process accounts for unitemporal and some bitemporal epilepsy, but that independent onset of seizures from each temporal lobe detected by depth EEG may also indicate extratemporal foci.

Temporal lobectomy in patients with bitemporal epilepsy defined by depth electroencephalography

Patient selection for temporal lobectomy was reviewed for 23 patients with seizures that arose independently from each temporal lobe as detected by depth electroencephalography (EEG). Although neuropsychological testing, interictal EEG findings, imaging studies, and subclinical seizures were also considered, all patients offered temporal lobectomy had (1) at least 50% of the clinical seizures originating from the lobe to be resected, (2) adequate contralateral memory on testing with amobarbital, and (3) no clear evidence of an extratemporal focus. Eleven patients underwent temporal lobectomy. Pathological findings were considered positive in all nine specimens reviewed. Nine patients had no seizures, one had greater than 75% reduction in seizure frequency, and 1 had 50 to 75% reduction. Pathological features and clinical outcome were similar in the 6 patients with fewer than 80% and the 5 patients with at least 80% of seizures originating from the resected lobe. Thus, having fewer than 80% of seizures originate from one temporal lobe should not be an absolute contraindication for temporal lobectomy.

Significance of Bisynchronous Spike‐Waves in Patients with Temporal Lobe Spikes

We examined the clinical significance of bisynchronous spike-wave complexes which appear in EEGs of some patients with focal spikes in one or both temporal lobes. Few features distinguished patients with bisynchronous spike-waves from those with only focal temporal spikes: a higher incidence of patients with more than two grand mal seizures a year (43 vs. 7%) and a younger age at last recording (22.5 vs. 28.3 years) were the only statistically reliable factors. Proportion of patients with complex partial seizures (CPS) (100%), age of CPS onset, incidence of febrile convulsions, intellectual level, and normal neurologic examination were features common to the two groups. In contrast to other studies which did not exclude influencing variables such as extratemporal spike foci, our group with bisynchronous spike-waves fared equally well after temporal lobectomy as did patients with temporal spikes alone. All 6 patients with spike-waves obtained a reduction of at least 50% in seizure frequency and 5 of the 6 (83%) had a greater than 90% reduction. Sixteen of 17 patients (94%) without spike-waves had a reduction of at least 50% and 14 of the 17 (82%) had a greater than 90% reduction of seizures.

Personality correlates of chronic, unstable epilepsy

AbstractThe present study included 60 males with unstable epilepsy despite therapeutic levels of anticopulsants. They were middle age or older (x = 45.6 years; s.d. = 11.1), with chronic documented seizures (X = 17.1 years; s.d. = 13.2). When type of EEG abnormality was considered, significant differences were found on two individual MMPI scales. Scale L was significantly higher in patients with right temporal lobe abnormalities compared to left temporal foci. The group with generalized EEG findings also scored higher on L compared to those with left temporal, extratemporal and normal EEG patterns. In addition, those with right temporal lobe EEG abnormalities and the group with extratemporal foci scored significantly higher on scale Pd than those with generalized, left temporal or normal EEGs. No differences were found on the MMPI when chronicity, trauma or age at onset were considered. Thus, subtle personality differences as measured by the MMPI were found only when type and laterality of the EEG abnormalities were controlled.

Type I/II complex partial seizures: no correlation with surgical outcome.

Three complex partial seizure (CPS) types have been described based upon the behaviors seen at the onset of the ictal event. Type I CPSs are preceded by a motionless stare and have been correlated with a temporal focus, whereas Type II CPSs are not preceded by a motionless stare and have been correlated with an extratemporal focus. A third type of CPS, temporal lobe syncope, has been correlated with bilateral mesial temporal foci. We examined the utility of this CPS classification system in predicting surgical outcomes by reviewing our patients who had undergone surgical excision of their epileptogenic foci for the treatment of medically refractory CPSs. Forty-six consecutive patients were evaluated, with the seizure focus ultimately found to be temporal in 41 and frontal in 5. All 5 patients with frontal foci had Type II CPSs; of the 41 patients with temporal foci, 20 had Type I and 21 had the Type II CPSs. Twenty of 26 patients with Type II CPSs and 18 of 20 patients with Type I CPSs had a good or excellent outcome. Although our data suggest that patients with frontal foci have Type II CPSs, the reverse is not true. Furthermore, CPS type is not correlated with the surgical outcome, since there was no significant difference between the CPS type and the category of surgical outcome.

Clinical features and ictal patterns in epileptic patients with EEG temporal lobe foci

AbstractThe clinical features and subjective ictal phenomena in 270 epileptic patients with electrographic temporal lobe foci are reported. The ictal manifestations observed in 199 of these patients are described and compared with those in epileptic patients with extratemporal foci reported previously. Sixty‐four percent of the patients reported historical data of possible etiological importance, but one could be reasonably certain of the cause in only 27%. Eighty‐three percent of the patients reported auras, 80% exhibited localized motor activity, and 95% demonstrated automatic behavior. Compared to patients with extratemporal foci, the patients reported here had a higher incidence of visceral (41%), complex (52%), and olfactory‐gustatory (13%) auras and of automatic behavior. On the other hand, no ictal phenomenon was unique to patients with temporal localization. The data do not support the concept of an association between “temporal lobe epilepsy” and violence.

Electrophysiological correlates of pathology and surgical results in temporal lobe epilepsy.

Routine pre-operative EEG studies as well as direct brain recording and stimulation carried out during operations were analysed for 59 patients subjected to a standard unilateral anterior temporal lobectomy for the treatment of epilepsy. All patients in the present series were 16 years old or older at the time of operation, which was invariably carried out under local scalp analgesia only. Electrophysiological findings was correlated with pathological changes noted in the resected temporal lobes, and with the effects of surgery upon seizure activity. Pre-operative EEG data correlated with each of four pathological categories when sphenoidal electrodes and intravenous barbiturate narcosis were emplyed. Thirty of 31 patients with mesial temporal sclerosis demonstrated medial temporal primary spike foci, frequently with independent contralateral and extratemporal secondary foci. In addition, one-third of these patients demonstrated unilateral focal decreased barbiturate-induced fast activity in the corresponding sphenoidal to ear channels. Twelve patients with other specific medial focal lesions (mostly hamartomas) also had medial temporal primary foci, often with independent contralateral secondaries but never with extratemporal foci. Two patients in this group also demonstrated focal decreased fast activity in the appropriate sphenoidal-ear channel. Both of these groups did very well post-operatively with respect to their epilepsy. Five patients with large temporal convexity cicatrices antedating seizures all demonstrated lateral temporal primary spike foci without independent secondary foci or focal decreased fast activity and did not do as well post-operatively as the first two groups. Eleven patients had only non-specific changes in the resected temporal lobe and in general did not benefit from surgery. Various combinations of primary and independent secondary spike foci were seen. Only this group demonstrated diffuse or bifrontal spikes during initial EEG recording, and basal mid-line spikes with intravenous thiopentone. Pecilar sharp notched spike were also very common in this group, but not unique to it. Focal decreases in barbiturate-induced fast activity were not noted.