Bilateral epileptogenesis in temporal lobe epilepsy due to unilateral hippocampal sclerosis: A case series.

INTRODUCTION: Bitemporal epilepsy (biTLE), a potential cause of failure in TLE surgery, is rarely associated with unilateral HS and could be suggested by not lateralizing ictal scalp EEG/interictal PET-FDG findings. We evaluated the proportion of biTLE in a population of drug-resistant TLE-HS subjects who underwent intracranial investigation for lateralizing purpose. METHODS: We retrospectively included all consecutive refractory TLE-HS patients and not lateralizing ictal scalp EEG/interictal PET-FDG findings, investigated by intracranial bilateral longitudinal hippocampal electrodes. Demographic characteristics, electroclinical findings and seizure outcome were evaluated. RESULTS: We identified 14 subjects (7 males; mean age 39.5 years; mean age at disease onset 14.4 years), 7 of them had biTLE diagnosed after intracranial investigations. In the remaining 7 with unilateral epileptogenesis (uniTLE) anterior temporal lobectomy was performed (6/7 were in Engel class I). Preoperative neuropsychological assessment differentiated biTLE from uniTLE, as it was normal in six uniTLE patients but only in one with biTLE (p < 0.05). CONCLUSIONS: Not lateralizing ictal scalp EEG and functional imaging findings in TLEHS should alert about the possibility of a true biTLE also in presence of unilateral findings at MRI. Intracranial investigations with bilateral longitudinal hippocampal electrodes can localize the EZ with a good risk-benefit profile. Consistently with the warning on memory functions in TLE patients explored by using longitudinal hippocampal electrodes, further studies are needed to better define the optimal investigation strategy.

Long-term seizure outcome in frontal lobe epilepsy surgery.

PURPOSE: The purpose of this study was to report long-term seizure outcome in patients who underwent frontal lobe epilepsy (FLE) surgery. METHOD: This retrospective study included 44 consecutive subjects who underwent resective surgery for intractable FLE at IRCCS NEUROMED (period 2001-2014), followed up for at least 2 years (mean: 8.7 years). All patients underwent noninvasive presurgical evaluation and/or invasive electroencephalography (EEG) monitoring when nonconcordant data were obtained or epileptogenic zone was hypothesized to be close to the eloquent cortex. Electroclinical, neuroimaging, surgical data, and histology were compared to seizure outcome. RESULTS: Mean epilepsy duration was 19 years; mean age at surgery was 31.6 years. Preoperative magnetic resonance imaging (MRI) showed a frontal lesion in 86.4 % of cases. Scalp video-electroencephalography (VEEG) monitoring detected a focal ictal onset in 90% of cases. Twenty-seven patients (61.4%) underwent invasive recordings. Resections involved dorsolateral (47.7%), medial (9%), orbital (13.6%), and rolandic (13.6%) region. Lobectomy within functional boundaries was performed in the remaining 7 cases (16%). Transient and permanent neurological deficits were observed in 2 and 3 cases, respectively. Histology revealed focal cortical dysplasia (45.5%), World Health Organization (WHO) I-II grade tumors (15.9%), gliosis (22.7%), vascular malformations (4.5%), Rasmussen encephalitis (6.8%), and normal tissue (4.5%). At last observation 68.1% of patients were in Engel's class I, 11.4% in class II, 9% in class III, and 11.4% in class IV. A favorable outcome was associated with focal ictal scalp EEG onset (p = 0.0357). CONCLUSION: Surgery is a safe treatment option in drug-resistant FLE with a satisfying long-term outcome. These data highlight the importance of an appropriate selection of potential surgical candidates.

Possible autoantibody-negative limbic encephalitis after anterior temporal lobectomy for hippocampal sclerosis.

PURPOSE: Amnestic syndromes are acknowledged to be associated to bilateral hippocampal damage. MATERIALS AND METHODS: We briefly report the case of a young man who underwent anterior left temporal lobectomy for a medically refractory temporal lobe epilepsy due to hippocampal sclerosis with an excellent seizure and neuropsychological outcome. Approximately 10 years later, he presented with a subacute severe global amnesia and neuroimaging findings of a damage involving the contralateral mesial temporal lobe structures. RESULTS: A diagnosis of a possible autoimmune encephalitis was made. CONCLUSIONS: Due to its peculiarities (compared with other cases of bilateral temporal lesions, the damage occurred on two distinct occasions), this case might contribute to shed light on the issue of the possible contralateral reorganization of memory processes subserved by the mesial temporal lobe structures chronically involved in epileptogenesis.

Temporal pole abnormalities detected by 3 T MRI in temporal lobe epilepsy due to hippocampal sclerosis: No influence on seizure outcome after surgery.

PURPOSE: To assess the clinical significance of temporal pole abnormalities (temporopolar blurring, TB, and temporopolar atrophy, TA) detected by using 3 Tesla MRI in the preoperative workup in patients with temporal lobe epilepsy due to hippocampal sclerosis (TLE-HS) who underwent surgery. METHODS: We studied 78 consecutive patients with TLE-HS who underwent surgery and were followed up for at least 2 years. Based on findings of pre-surgical 3 Tesla MRI, patients were subdivided in subgroups according to the presence of TB or TA. Subgroups were compared on demographic, clinical, neuropsychological data and seizure outcome. RESULTS: TB was found in 39 (50%) patients, while TA was found in 32 (41%) patients, always ipsilateral to HS, with a considerable degree of overlap (69%) between TB and TA (p=0.01). Patients with temporopolar abnormalities did not significantly differ from those without TB or TA with regard to sex, age, age of epilepsy onset, duration of epilepsy, history of febrile convulsions or birth complications, side of surgery, seizure frequency at surgery, presence of GTCSs, and, in particular, seizure outcome. On the other hand, TB patients show a less frequent family history of epilepsy (p<.05) while age at epilepsy onset showed a trend to be lower in the TB group (p=.09). Patients with temporopolar atrophy did not significantly differ from those without TA on any variable, except for age at epilepsy onset, which was significantly lower for the TA group (p<.05). History of birth complications and longer duration of epilepsy also showed a trend to be associated with TA (p=.08). Multivariate analysis corroborated the association between temporopolar abnormalities and absence of family history of epilepsy and history of birth complications. CONCLUSIONS: High-field 3 T MRI in the preoperative workup for epilepsy surgery confirms that temporopolar abnormalities are frequent findings in TLE-HS patients and may be helpful to lateralize the epileptogenic zone. Their presence did not influence seizure outcome.

Temporal pole abnormalities in temporal lobe epilepsy with hippocampal sclerosis: Clinical significance and seizure outcome after surgery.

PURPOSE: To assess the clinical significance of temporal pole abnormalities (temporopolar blurring, TB, and temporopolar atrophy, TA) in patients with temporal lobe epilepsy (TLE) and hippocampal sclerosis (HS) with a long post-surgical follow-up. METHODS: We studied 60 consecutive patients with TLE-HS and 1.5 preoperative MRI scans who underwent surgery and were followed up for at least 5 years (mean follow-up 7.3 years). Based on findings of pre-surgical MRI, patients were classified according to the presence of TB or TA. Groups were compared on demographic, clinical, neuropsychological data, and seizure outcome. RESULTS: TB was found in 37 (62%) patients, while TA was found in 35 (58%) patients, always ipsilateral to HS, with a high degree of overlap (83%) between TB and TA (p<0.001). Patients with TB did not differ from those without TB with regard to history of febrile convulsions, GTCSs, age of epilepsy onset, side of surgery, seizure frequency, seizure outcome, and neuropsychological outcome. On the other hand, they were significantly older, had a longer duration of epilepsy, and displayed lower preoperative scores on several neuropsychological tests. Similar findings were observed for TA. Multivariate analysis corroborated the association between temporopolar abnormalities and age at onset, age at surgery (for TB only), and lower preoperative scores on some neuropsychological tests. CONCLUSIONS: Temporopolar abnormalities are frequent in patients with TLE-HS. Our data support the hypothesis that TB and TA are caused by seizure-related damages. These abnormalities did not influence seizure outcome, even after a long-term post-surgical follow-up.

Acute postoperative seizures and long-term seizure outcome after surgery for hippocampal sclerosis.

PURPOSE: To assess the incidence and the prognostic value of acute postoperative seizures (APOS) in patients surgically treated for drug-resistant temporal lobe epilepsy due to hippocampal sclerosis (TLE-HS). METHODS: We studied 139 consecutive patients with TLE-HS who underwent epilepsy surgery and were followed up for at least 5 years (mean duration of follow-up 9.1 years, range 5-15). Medical charts were reviewed to identify APOS, defined as ictal events with the exception of auras occurring within the first 7 days after surgery. Seizure outcome was determined at annual intervals. Patients who were in Engel Class Ia at the last contact were classified as having a favorable outcome. RESULTS: Seizure outcome was favorable in 99 patients (71%). Six patients (4%) experienced APOS and in all cases their clinical manifestations were similar to the habitual preoperative seizures. All patients with APOS had unfavorable long-term outcome, as compared with 35 (26%) of 133 in whom APOS did not occur (p<0.001). CONCLUSIONS: Our study suggests that APOS, despite being relatively uncommon in patients undergoing resective surgery for TLE-HS, are associated with a worse long-term seizure outcome. Given some study limitations, our findings should be regarded as preliminary and need confirmation from future larger, prospective, multicenter studies.

Serial postoperative awake and sleep EEG and long-term seizure outcome after anterior temporal lobectomy for hippocampal sclerosis.

OBJECTIVE: To test if postoperative prolonged awake and sleep EEG monitoring predict long-term seizure outcome in patients operated for drug-resistant temporal lobe epilepsy due to hippocampal sclerosis (TLE-HS). METHODS: This longitudinal study includes 107 patients with MTLE-HS who underwent anterior temporal lobectomy (ATL), were followed for at least 5 years (mean 8.3, range 5-12), had postoperative EEG after 2 months and at least one prolonged video-EEG monitoring during both wakefulness and sleep after 12 and 24 months. At each follow-up visit, the presence of interictal epileptiform discharges (IED) was determined, and seizure outcome was evaluated. RESULTS: Sixty-six patients (62%) remained free from auras and seizures throughout the follow-up period. Twenty-six (24%), 22 (21%), and 16 (16%) patients had IED at the 2-month, 12-month, and 24-month follow-up, respectively. The presence of IED at each time point was found to be associated with seizure or aura recurrence. Sleep recording contributed to the identification of patients with IED, as half of patients with IED displayed anomalies in sleep EEG only. In multivariate analysis, the presence of IED 2 months after surgery was found to be associated with seizure or aura recurrence independent of pre-operative factors consistently reported as outcome predictors in the literature. CONCLUSIONS: The presence of IED in serial postoperative EEG including sleep recording may predict long-term seizure outcome after ATL for TLE-HS. Serial postoperative EEGs may contribute to outcome prediction and help making decision about medication withdrawal in patients operated for TLE-HS.

Prognostic significance of acute postoperative seizures in extra-temporal lobe epilepsy surgery.

OBJECTIVE: This study aims to assess the prognostic value of acute postoperative seizures (APOS) in patients surgically treated for drug-resistant extra-temporal lobe (ET) epilepsy. METHODS: We studied 77 consecutive patients with ET epilepsy who underwent epilepsy surgery and were followed up for at least 2 years (mean duration of follow-up 6.2 years, range 2-14). Medical charts were reviewed to identify APOS, defined as ictal events with the exception of auras occurring within the first 7 days after surgery. Seizure outcome was determined at annual intervals. Patients who were in Engel Class I at the last contact were classified as having a favourable outcome. RESULTS: Seizure outcome was favourable in 47 patients (61%). The occurrence of APOS and incompleteness of resection were found to be independently associated with unfavourable outcome in a multiple regression model including all preoperative factors identified as outcome predictors in univariate analysis. Duration of illness was the only independent preoperative predictor of APOS. CONCLUSIONS: Our study suggests that APOS may predict long-term outcome in patients undergoing resective surgery for ET epilepsy. Given some study limitations, our findings should be regarded as preliminary and need confirmation from future larger, prospective, multicentre studies. SIGNIFICANCE: Caution may be required in the clinical management of patients experiencing APOS.

Prognostic significance of serial postoperative EEG in extratemporal lobe epilepsy surgery.

OBJECTIVE: To assess the prognostic value of postoperative EEG in patients surgically treated for drug-resistant extra-temporal lobe (ET) epilepsy. METHODS: We studied 63 consecutive patients with ET epilepsy who underwent epilepsy surgery and were followed up for at least 2 years (mean duration of follow-up 6.2 ± 2.3 years, range 2-12). Follow-up evaluations were performed 2, 12, and 24 months after surgery, and included standard EEG (at 2 months) and long-term video-EEG monitoring during both wakefulness and sleep (at 12 and 24 months). Seizure outcome was determined at each follow-up evaluation, and then at yearly intervals. Patients who were in Engel Class I at the last contact were classified as having a good outcome. RESULTS: Seizure outcome was good in 39 patients (62%). The presence of interictal epileptiform discharges (IED) in postoperative EEG at each time point was found to be associated with poor outcome. The strength of this association was greater for awake plus sleep recording as compared with awake recording alone. In a multiple regression model including all pre- and post-operative factors identified as predictors of outcome in univariate analysis, the presence of early (2 months after surgery) EEG epileptiform abnormalities was found to be independently associated with poor seizure outcome. CONCLUSIONS: Postoperative IED may predict long-term outcome in patients undergoing resective surgery for ET epilepsy. SIGNIFICANCE: The increase in risk of unfavourable outcome associated with EEG epileptiform abnormalities detected as early as two months after surgery may have substantial practical importance. Serial postoperative EEGs including sleep recording may add further predictive power and help making decision about antiepileptic drug discontinuation.

Memory outcome 2 years after anterior temporal lobectomy in patients with drug-resistant epilepsy.

PURPOSE: Memory decline is often observed after anterior temporal lobectomy (ATL), particularly in patients with dominant hemisphere resections. However, the follow-up length has been 1 year or less in most studies. Our aims were to examine postoperative memory changes over a longer period and to identify baseline demographic and clinical predictors of memory outcome. METHODS: We administered material-specific memory tests at baseline, and 1 and 2 years after surgery to 82 consecutive right-handed patients (52% males) who underwent ATL for drug-resistant temporal lobe epilepsy (TLE) (35 left, 47 right) after a non-invasive presurgical protocol. Repeated measures multivariate analysis of variance (RM-MANOVA) was used to examine the relationship between changes in memory tests scores over time and side of TLE and pathology. Also, standardized residual change scores were calculated for each memory test and entered in multiple linear regression models aimed at identifying baseline predictors of better memory outcome. RESULTS: RM-MANOVA revealed a significant change in memory test scores over time, with an interaction between time and side of surgery, as 2 years after surgery patients with RTLE were improved while patients with LTLE were not worse as compared with baseline. Pathology was not associated with changes in memory scores. In multiple regression analysis, significant associations were found between right TLE and greater improvement in verbal memory, younger age and greater improvement in visuospatial memory, and male gender and greater improvement in both verbal and visuospatial memory. CONCLUSIONS: Our results suggest that the long-term memory outcome of TLE patients undergoing ATL without invasive presurgical assessment may be good in most cases not only for right-sided but also for left-sided resections.

Drug-resistant temporal lobe epilepsy due to cavernous malformations.

OBJECT: Supratentorial cavernous angiomas may be associated with drug-resistant focal epilepsy. Surgical removal of the malformation may result in seizure control in a number of patients, although in most studies a long history and high frequency of attacks have been recognized as indicators of unfavorable seizure outcome. In the literature, there are no clear indications regarding the optimal diagnostic presurgical workup and the surgical strategy for this particular subgroup of patients with symptomatic epilepsy. In this paper the authors focus on the preoperative workup and the surgical management of the disease in eight consecutive patients undergoing surgery for drug-resistant temporal lobe epilepsy (TLE) due to cavernous malformations (CMs), and the relevant literature on this issue is also reviewed. METHODS: Preoperatively, all patients were assessed using a noninvasive protocol aimed at localizing the epileptogenic zone on the basis of anatomical, electrical, and clinical criteria. The presurgical assessment yielded an indication for lesionectomy in two cases, lesionectomy plus anteromesial temporal lobectomy in four cases, and lesionectomy plus extended temporal lobectomy in two cases. At follow-up examinations, seizure, neuropsychological, and psychiatric outcomes were all evaluated. Seven patients were categorized in Engel Class IA (seizure free), and one was categorized in Engel Class IB (occasional auras only). No adverse effects on neuropsychological or psychosocial functioning were observed. CONCLUSIONS: Epilepsy surgery can be performed with excellent results in patients with intractable TLE caused by CMs. Noninvasive presurgical evaluation of these patients may enable a tailored approach, providing complete seizure relief in most cases.

Factors associated with generic and disease-specific quality of life in temporal lobe epilepsy.

PURPOSE: We aimed at further elucidating the association between quality of life (QOL) and sociodemographic factors, clinical seizure factors, depression and anxiety in drug-resistant temporal lobe epilepsy (TLE). METHODS: We studied 106 consecutive adult right-handed patients (mean age 35.4 +/- 9.7; 50% males; IQ> or = 70) with drug-resistant unilateral (59% right) TLE (70% hippocampal sclerosis, 30% tumors or other lesions), who underwent a comprehensive non-invasive pre-surgical protocol. They completed the Beck Depression Inventory (BDI) and the State Form of the Spielberger State-Trait Anxiety Inventory (STAI). To measure QOL, we used both a generic instrument, the WHOQOL-100, and a disease-specific instrument, the 31-item quality of life in epilepsy (QOLIE-31). Multiple linear regression analysis was used to examine the relationship between each QOL domain and age, gender, education, side of TLE, duration of epilepsy, seizure frequency, and level of depression and anxiety. RESULTS: Severity of depressive symptoms was significantly associated with lower scores across most QOL domains. Depression was consistently the strongest predictor of lower scores on almost all QOL domains. Also, severity of anxiety symptoms was significantly associated with lower scores across many QOL domains. Independent significant relationships between QOL and sociodemographic or clinical epilepsy variables were limited in number and strength. CONCLUSIONS: Our findings suggest that QOL in TLE might be substantially affected by the presence and severity of depressive symptoms and, to a lesser degree, of anxiety symptoms. While clinical seizure variables had a weaker association with QOL, the absence of seizure-free patients might have obscured a relation between seizure frequency and QOL. Healthcare professionals should be aware of the significance of patients' emotional state and of the role it plays for their QOL. Adopting a biopsychosocial approach might be useful to address patients' needs.

Postoperative EEG and seizure outcome in temporal lobe epilepsy surgery.

OBJECTIVE: To assess the prognostic value of scalp electroencephalogram (EEG) after epilepsy surgery, we investigated whether postoperative EEG abnormalities (interictal epileptiform discharges, IED; interictal slow activity, ISA) were associated with seizure outcome and other patient characteristics after resective surgery in patients with temporal lobe epilepsy (TLE). METHODS: Sixty-two patients with medically refractory TLE who underwent surgery were studied. Patients were categorized according to etiology (mesiotemporal sclerosis vs. tumors/cortical dysplasias); extent of surgical resection (extensive vs. limited); and amount of preoperative IED on wake EEG (oligospikers, <1 IED/h, vs. spikers). Patients were also classified as seizure-free (SF) or having persistent seizures/auras (not-SF) during follow up visits 1 month and 1 year after surgery. Preoperative 60-min interictal EEGs were evaluated for IED and ISA, and compared to postoperative wake EEGs. RESULTS: Seizures/auras persisted in 16/62 (25.8%) patients at 1 month and in 8/62 (12.9%) at 1 year follow up. ISA was not significantly related to outcome. Of 42 patients with EEG negative for IED at 1 month, 4 were not-SF; at 1 year, one of 44 such patients was not-SF. IED was significantly associated with seizure/aura persistence in patients categorized as mesiotemporal sclerosis and with extensive surgery. Oligospikers and spikers on preoperative EEG showed no differences in the postoperative seizure outcome, excellent in both cases; moreover, the presence of postoperative IEDs indicated auras/seizures persistence apart from the preoperative EEG spike frequency. CONCLUSIONS: Our study showed that the presence of IED of postoperatve EEG strongly indicates seizure/aura persistence. Therefore, serial EEGs should be included in postoperative follow up schedules as a crucial tool in evaluating seizure outcome.