Mortality after temporal lobe epilepsy surgery

Purpose: To report mortality, after a longer interval, in a cohort of patients with drug‐resistant epilepsy treated by temporal lobe surgery between 1975 and 1995. A previous audit of these patients ending December 1, 1997 observed a standardized mortality ratio (SMR) of 4.5. Methods: We analyzed mortality in a cohort of 306 patients with temporal lobe epilepsy (TLE) who underwent temporal lobe resections between December 1, 1975 and December 1, 1995. Deaths occurring after December 1,1997 and until December 1, 2009 were evaluated. Medical records, death certificates, postmortem examination reports, coroner officer’s reports, and coroner’s inquest reports were sought, and causes of death were ascertained. Sudden unexpected death in epilepsy (SUDEP) cases were identified. Key Findings: In 3,569 person‐years of follow‐up 19 deaths occurred, [SMR 2.00, 95% confidence interval (CI) 1.27–3.13], 14 men (SMR 2.01, 95% CI 1.19–3.39) and 5 women (SMR 1.68, 95% CI 0.70–4.03). On analysis of subgroups, SMRs were significantly elevated in patients with mesial temporal sclerosis (MTS) (SMR 2.50, 95% CI 1.38–4.51), men with MTS (SMR 3.12, 95% CI 1.56–6.25), men with nonspecific lesions (SMR 2.68, 95% CI 1.00–7.09), and right‐sided resections in MTS (SMR 3.33, 95% CI 1.39–8.00). During follow‐up, six SUDEP cases were observed with a rate of 1/595 person‐years. Significance: In this cohort, the risk for premature death in patients undergoing TLE surgery decreased over time but remained above the standard population. Men had a slightly higher risk than women, as did right‐sided resections in MTS, confirming this observation in the original cohort. Although lower, the risk of SUDEP remained. Without up‐to‐date information on seizure outcome, we were unable to directly relate this to mortality.     

Antiepileptic drug withdrawal in patients with temporal lobe epilepsy undergoing presurgical video-EEG monitoring

PURPOSE: To investigate antiepileptic drug (AED) withdrawal during video-EEG monitoring in adult patients with temporal lobe epilepsy (TLE). METHODS: Between 1995 and 1997, 102 consecutive patients with refractory TLE were admitted to the epilepsy monitoring unit for presurgical evaluation. Patients were monitored with ongoing AEDs being rapidly decreased and discontinued in 4-6 days. The monitoring was continued until sufficient numbers of seizures were recorded. Serum AED levels were checked at admission and after the first complex partial seizure (CPS). RESULTS: In all, 89 patients had 429 CPSs (mean, 4.8 per patient), including 156 (36.4%) secondarily generalized. A mean of 153.8 h (16-451 h) was required for completing the monitoring in each patient. Forty-three (48.3%) patients experienced seizure clusters, and eight (9.0%) had generalized seizures that had never occurred or had been absent for years. However, none evolved to status epilepticus. Carbamazepine was the most commonly used AED in 71.9% of patients, followed by valproate and phenytoin. When the first CPS occurred, mean 77.2 h since the beginning of the monitoring, serum levels of these three AEDs were mostly subtherapeutic rather than minimal. CONCLUSIONS: Acute AED withdrawal effectively provoked seizures in TLE patients undergoing presurgical video-EEG monitoring. However, nearly 50% of patients had seizure clusters or secondarily generalized seizures. Serum AED levels were mostly subtherapeutic when the first CPS occurred.     

Depression in temporal lobe epilepsy before epilepsy surgery

PURPOSE: This study examined the association of depression with laterality of epilepsy surgery in patients with temporal lobe epilepsy before standard lobectomy. METHODS: Forty-nine patients presented for EEG telemetry for localization of epilepsy and eventual temporal lobectomy. Patients underwent routine neuropsychiatric evaluation blinded for epileptic focus, including ratings on depression. Patients were grouped according to right (n = 25, M = 10/F = 15) and left (n = 24, M = 13/F = 11) temporal lobectomy. Analysis of variance included side of surgery as grouping variable and sex, general depressive, cognitive depressive, and vegetative depressive symptoms as dependent variables. Chi2 analyses included categoric variables of sex, handedness, education, neuropathologic findings, and current affective disorders. t Tests were performed on variables of age, epilepsy duration, and cognitive function. RESULTS: Right and left temporal epilepsy groups did not differ with regard to sex, handedness, age, duration of epilepsy, education, cognitive function, and neuropathology. Patients with right temporal epilepsy rated higher on general, cognitive. and vegetative depression scores. Women scored higher on general, cognitive, and vegetative depression scores. Current affective disorders were more common in the right temporal epilepsy group. CONCLUSIONS: Depression ratings and diagnoses were more prominent in patients with right temporal lobe epilepsy and in women in particular. The strength of this laterality finding lies in the selection of patients, as all underwent epilepsy surgery. The finding on gender difference partly reflects the higher incidence of depression in women and needs further exploration. The laterality finding contrasts with recent findings in epilepsy, stroke, and trauma that associate depression with left hemispheric lesions. However, our results are consistent with findings in electrically hyperactive lesions such as gelastic and dacrystic epilepsy.     

Surgery for medically intractable temporal lobe epilepsy during early life

PURPOSE: Temporal lobe epilepsy (TLE) in early life is often a catastrophic disorder with pharmacoresistant seizures and secondary neurological deterioration. there is little data available regarding epilepsy surgery performed in infants and young children and no prior study has focused on tle. METHODS: We analyzed the results of temporal resection for epilepsy as the primary indication in children less than age 5 years who had at least 2 years of follow-up. RESULTS: 20 children (14 males) were identified with a mean age at surgery of 26 months and a mean age at seizure onset of 12 months. Clinical presentation was diverse. Typical psychomotor seizures (n = 4; mean age at surgery 37 months) were followed by prominent motor changes (n = 7; 30 months) and were occasionally isolated (n = 3; 23 months). Epileptic spasms were noted in six patients and were frequently associated with lateralizing features. The interictal EEG was lateralizing in 15 patients and the ictal EEG was lateralizing in 18 patients. Brain MRI provided localizing value in 16 patients, ictal SPECT was concordant in 4/8 cases. Invasive EEG was employed in six cases. At mean follow-up of 5.5 years, 65% of the children were seizure-free and 15% had >90% seizure reduction. Morbidity included infection and hydrocephalus in one case and stroke-related hemiparesis in two cases. Cortical dysplasia was identified in eight children, tumors in eight including two DNET, two ganglioglioma, and four malignant tumors. Hippocampal sclerosis was present in four cases, always as dual pathology. CONCLUSION: TLE presents in early life with varied and severe manifestations. Excisional procedures in this age group are associated with favorable seizure reduction similar to older children and in adults.     

Latency to first seizure after temporal lobectomy predicts long-term outcome

Purpose: Temporal lobectomy is a well‐established treatment for refractory temporal lobe epilepsy, yet many patients experience at least one seizure postoperatively. Little is known about the prognostic significance of the time from surgery to first seizure relapse in predicting long‐term outcome. Methods: In a retrospective analysis of patients who reported at least one complex partial seizure (CPS) or generalized tonic–clonic seizure (GTCS) after anterior temporal lobectomy (n = 268), we used a nominal response logistic model to predict the odds ratio (OR) of a seizure outcome based on length of the latency period from surgery to first postoperative seizure. A modified Engel outcome class scheme was used. We controlled for factors known to influence postoperative outcome, including history of tonic–clonic seizures, intelligence quotient (IQ), preoperative seizure frequency, magnetic resonance imaging (MRI) findings, and history of febrile convulsions. Results: In the univariate analysis, the latency from surgery to the first postoperative disabling seizure was significantly associated with long‐term outcome. Longer latency was associated with higher odds of being seizure‐free or improved (modified Engel’s classes 1, 2, and 3) relative to the unimproved state (class 4) (p < 0.001, 0.001 and 0.004, respectively). Conversely, a shorter latency increased the likelihood of achieving the worst prognosis (class 4) relative to class 1 (p < 0.001). Multivariate analysis yielded similar results. Discussion: Latency to the first postoperative seizure predicts long‐term outcome, with short latencies portending poor prognosis and long latencies portending a good prognosis. This information can be used for patient counseling and may influence decisions regarding reoperation.     

Surgery for temporal lobe epilepsy after cerebral malaria

The most common indication for epilepsy surgery is temporal lobe epilepsy (TLE) which usually is divided into two categories, mesial and lateral TLE. The commonest pathology underlying mesial temporal lobe epilepsy (MTLE) is mesial temporal sclerosis (MTS); we report on a 50-year-old male patient, who contracted cerebral malaria and developed MTLE shortly thereafter. Magnetic resonance imaging (MRI) showed MTS. Surgical treatment was an anteromedial temporal lobe resection with amygdalohippocampectomy. The patient is seizure free, 36 months after surgical treatment. This is the first report describing MTLE-onset subsequent to cerebral malaria and discussing the potential pathophysiological relationship between cerebral malaria and MTS.     

Memory functions following surgery for temporal lobe epilepsy in children

Surgical treatment appears to improve the cognitive prognosis in children undergoing surgery for temporal lobe epilepsy (TLE). The beneficial effects of surgery on memory functions, particularly on material-specific memory, are more difficult to assess because of potentially interacting factors such as age range, intellectual level, left-handedness, type of surgery and seizure outcome. This study investigated memory functions in 20 right-handed children who had left or right-temporal lobe surgery - including hippocampectomy - and became seizure-free. The neuropsychological evaluation included tests measuring verbally and visually mediated episodic memory, everyday memory as well as attention/working memory and language/semantic memory. We also assessed the relationships between age of seizure onset, general cognitive ability and memory functions. Children with TLE showed poor memory efficiency before surgery that tended to improve about 1 year after surgery. We found a material-specific memory effect, especially after surgery-9 (out of 12) children with left TLE had worse verbal memory results while 5 (out of 8) with right TLE had worse visual memory results. Post-operatively, most children had poor everyday memory performance on the Rivermead Behavioural Memory Test. No significant relationship was observed between episodic memory scores and age of epilepsy onset but children with early onset remained with lower Performance IQ values, Rey's figure copy scores and naming performances after surgery. Surgery significantly improved all the attention/working memory scores, some verbal episodic memory tasks and naming test performances. A different pattern of episodic and semantic memory limitations related to left or right TLE was observed.     

What is the current evidence on decision-making after referral for temporal lobe epilepsy surgery?: A review of the literature

OBJECTIVES: Many patients thought to have temporal lobe epilepsy, are evaluated for surgical treatment. Decision-making in epilepsy surgery is a multidisciplinary, phased process involving complex diagnostic tests. This study reviews the literature on the value of different tests to decide on whether to operate. METHODS: Articles were selected when based on the consensus decision whether to perform temporal lobe surgery, or on the consensus localization or lateralization of the epileptic focus. The articles were scrutinized for sources of bias as formulated in methodological guidelines for diagnostic studies (STARD). RESULTS: Most studies did not fulfill the criteria, largely because they addressed prognostic factors in operated patients only. Ten articles met our inclusion criteria. In most articles, a single test was studied; SPECT accounted for five papers. Unbiased comparison of the results was not possible. CONCLUSION: Surprisingly little research in epilepsy surgery has focused on the decision-making process as a whole. Future studies of the added value of consecutive tests are needed to avoid redundant testing, enable future cost-efficiency analyses, and provide guidelines for diagnostic strategies after referral for temporal lobe epilepsy surgery.     

Efficacy of temporal lobe surgery for epilepsy in patients with negative MRI for mesial temporal lobe sclerosis

Epilepsy surgery is a successful treatment for refractory temporal lobe epilepsy (TLE). Reports suggest fewer seizure-free outcomes for patients with TLE and who have a negative brain MRI (nMRI) for mesial temporal sclerosis. Data were collected prospectively from patients with nMRI who underwent temporal lobe surgery for TLE characterized by unilateral ictal temporal lobe seizure onset based on a scalp video electroencephalogram or invasive subdural electrode recordings. A total of 86 patients were followed for at least 24 months after surgery. Outcome was evaluated using the Engel classification. Seizure control was obtained by 55% (47/86) of patients (Class [CL]-I), 27% (23/86) showed significant improvement (CL-II) and 19% (16/86) were deemed surgical failures. Shorter duration of epilepsy, later onset of seizures, and ictal theta rhythm (5-7 Hz) were the most significant predictors of postoperative seizure control. Although hypometabolism on positron emission tomography scan and significant memory disparity (>2.5/8) were not significant prognosticators independently, cumulatively they were predictors for favorable outcome.     

Prognosis after temporal lobe epilepsy surgery: the value of combining predictors

Purpose: Although several independent predictors of seizure freedom after temporal lobe epilepsy surgery have been identified, their combined predictive value is largely unknown. Using a large database of operated patients, we assessed the combined predictive value of previously reported predictors included in a single multivariable model.
Methods: The database comprised a cohort of 484 patients who underwent temporal lobe surgery for drug-resistant epilepsy. Good outcome was defined as Engel class 1, one year after surgery. Previously reported independent predictors were tested in this cohort. To be included in our final prediction model, predictors had to show a multivariable p-value of <0.20.
Results: The final multivariable model included predictors obtained from the patient's history (absence of tonic–clonic seizures, absence of status epilepticus), magnetic resonance imaging [MRI; ipsilateral mesial temporal sclerosis (MTS), space occupying lesion], video electroencephalography (EEG; absence of ictal dystonic posturing, concordance between MRI and ictal EEG), and fluorodeoxyglucose positron emission tomography (FDG-PET; unilateral temporal abnormalities), that were related to seizure freedom in our data. The model showed an expected receiver-operating characteristic curve (ROC) area of 0.63 [95% confidence interval (CI) 0.57–0.68] for new patient populations. Intracranial monitoring and surgery-related parameters (including histology) were not important predictors of seizure freedom. Among patients with a high probability of seizure freedom, 85% were seizure-free one year after surgery; however, among patients with a high risk of not becoming seizure-free, still 40% were seizure-free one year after surgery.
Conclusion: We could only moderately predict seizure freedom after temporal lobe epilepsy surgery. It is particularly difficult to predict who will not become seizure-free after surgery.     

Hyperkinetic seizures in patients with temporal lobe epilepsy: clinical features and outcome after temporal lobe resection

Purpose: Temporal lobe epilepsy (TLE) is usually associated with automatisms. Hyperkinetic seizures are supposed to be unusual. Because we witnessed several patients with TLE and ictal hyperkinetic symptoms, we retrospectively assessed the number, clinical findings, and seizure outcome in such patients who had undergone temporal lobe resection. Methods: We reviewed medical history, video–electroencephalography (EEG) recording and neuroimaging of adult patients who underwent epilepsy surgery for TLE at the Kork Epilepsy Center over the last 20 years with a minimum postoperative follow‐up of 12 months. Key Findings: Among 294 patients who were resected exclusively in the temporal region, we identified 17 (6%) who presented with hyperkinetic semiology such as violent vocalization, complex movements of the proximal segments of the limbs, rotation of the trunk, pelvic thrusting, or early tonic or dystonic posturing. Most of the patients had a preceding aura. Ictal EEG activity was located in the corresponding temporal region, usually with a wide distribution over temporal electrodes with fast spread to unilateral frontal electrodes and to the contralateral side. Neuroimaging revealed extended lesions in the temporal lobe involving mesial and neocortical structures. Most of the patients underwent classical anterior temporal lobe resection including amygdalo‐hippocampectomy. Fourteen patients (82%) became completely seizure‐free (Engel class Ia). Histopathology showed mainly focal cortical dysplasia plus hippocampal sclerosis. Significance: Hyperkinetic seizure semiology may occasionally occur in patients with TLE and is, therefore, no contradiction to the hypothesis of TLE if scalp EEG patterns and neuroimaging findings correspond. The postoperative seizure outcome is favorable in such patients and not different from outcome data in classical TLE.     

颞叶癫痫术后脑脊液变化的动态研究

目的探讨颞叶癫痫术后颅内压力、脑脊液细胞及生化成分的动态改变情况,观察脑脊液成分变化和术后发热之间的关系。方法对北京协和医院神经外科2012年3月至8月期间颞叶癫痫手术后发热患者28例行腰椎穿刺,测量颅内压、脑脊液细胞学检查和生化分析。结果获得了颞叶癫痫术后颅内压的波动曲线、脑脊液细胞数及生化成分的改变曲线。结果颞叶癫痫手术后发热多与血性脑脊液刺激有关,与感染无关;颞叶癫痫手术后颅内压一般不高,通常不需使用降颅压药物。结论腰椎穿刺释放血性脑脊液对于颞叶癫痫术后发热疗效满意。     

Depression in temporal lobe epilepsy surgery patients: an FDG-PET study

PURPOSE: Depression is common in temporal lobe epilepsy (TLE) and after temporal lobectomy, and its etiology is obscure. In nonepileptic depression (including depression associated with other neurologic disorders), a consistent PET imaging finding is frontal lobe hypometabolism. Many TLE patients have hypometabolism involving frontal regions. Thus in data available from routine clinical assessments in an epilepsy surgery unit, we tested the hypothesis that the pattern of hypometabolism, particularly in the frontal lobe, may be associated with the depression seen in patients with TLE and TLE surgery. METHODS: We studied 23 medically refractory TLE patients who underwent anterior temporal lobectomy and who had preoperative FDG-PET scanning. All patients had pre- and postoperative psychiatric assessment. By using statistical parametric mapping (SPM-99), patterns of hypometabolism were compared between patients who had a preoperative history of depression (n=9) versus those who did not (n=14) and between those in whom postoperative depression developed (n=13) versus those in whom it did not (n=10). A significant region of hypometabolism was set at p<0.001 for a cluster of >or=20 contiguous voxels. RESULTS: Patients with a history of depression at any time preoperatively showed focal hypometabolism in ipsilateral orbitofrontal cortex compared with those who did not (t=4.64; p<0.001). Patients in whom depression developed postoperatively also showed hypometabolism in the ipsilateral orbitofrontal region (t=5.10; p<0.001). CONCLUSIONS: Although this study is methodologically limited, and other explanations merit consideration, orbitofrontal cortex dysfunction, already implicated in the pathophysiology of nonepileptic depression, may also be relevant to the depression of TLE and temporal lobectomy.     

Somatosensory auras in refractory temporal lobe epilepsy

PURPOSE: To determine the prevalence, manifestations, lateralizing value, and surgical prognostic value of somatosensory auras (SSAs) in patients with refractory temporal lobe epilepsy (TLE). METHODS: Eighty-one consecutive patients undergoing temporal lobectomy for refractory complex-partial seizures were screened for SSAs. The characteristics of the somatosensory phenomena, occurrence of other aura types, seizure semiology, findings of EEG and imaging studies, temporal lobe neuropathology, and postoperative seizure outcome were determined in each patient with SSAs. RESULTS: Nine (11%) of 81 patients with refractory temporal lobe seizures reported distinct SSAs as part of their habitual seizures. The most common manifestation of SSAs was tingling (eight of nine, 89%), but sensory loss (one of nine, 11%) and pain (one of nine, 11%) also were reported. Five patients had unilateral somatosensory symptoms, and four patients had bilateral somatosensory symptoms. Seizure origin was in the contralateral temporal lobe in four (80%) of five patients with unilateral SSAs, including all patients with unilateral SSAs affecting a limb. Partial temporal lobe resection produced complete seizure remission in all nine (100%) patients 1 year after surgery and in seven (78%) of nine patients 2 years after surgery. CONCLUSIONS: SSAs occur more frequently than previously appreciated in patients with refractory temporal lobe seizures and usually manifest as either unilateral or bilateral tingling. In patients with temporal lobe seizures, unilateral SSAs involving a limb suggest a seizure origin in the contralateral temporal lobe. The surgical outcome of TLE patients with SSAs is favorable. Thus the presence of SSAs should not serve as a deterrent to temporal lobe resection in patients with clearly defined TLE.     

Heart rate variability remains reduced and sympathetic tone elevated after temporal lobe epilepsy surgery

PurposeThere is evidence of autonomic dysregulation in temporal lobe epilepsy. The structures removed during temporal lobectomy are important centers of central cardiovascular control; therefore surgery may conceivably alter the cardiovascular autonomic function. The effects of temporal lobectomy on autonomic cardiac control are controversial. We investigated the effects of temporal lobectomy on heart rate variability (HRV) in the early and late postoperative periods.MethodsWe used 1-h ECG recordings to assess heart rate variability by spectral analysis in 24 consecutive patients who underwent temporal lobectomy due to intractable temporal lobe epilepsy. ECG recordings were performed before and twice (early and late) after surgery. The results were compared with age and sex matched controls.ResultsWhen compared with controls, all the time and frequency domain indices (SDRR, RMSSD, TP, LF and HF) were significantly lower in the patient group before surgery. Findings were similar in the early and late post-operative periods except that the LF/HF ratio increased in the patient group after the late post-operative period. Within the patient group, compared to pre-operative results, normalized HF was increased in the early post-operative period; however in the late post-operative period, LF/HF ratio was increased.ConclusionsThese findings show that in patients with intractable temporal lobe epilepsy, HRV is decreased globally in both sympathetic and parasympathetic domains. While the total HRV remains reduced throughout the postoperative periods, the LF/HF ratio, i.e., sympathovagal balance is altered, in favor of parasympathetic side early after surgery, but towards the sympathetic side after the first postoperative month.     

Long-term seizure outcome and its predictors in patients with recurrent seizures during the first year aftertemporal lobe resective epilepsy surgery

Purpose: The existing data on the implications of the characteristics of seizures that recur during the first year following epilepsy surgery on subsequent seizure outcome are conflicting. We investigated the impact of recurrent seizures in the first postoperative year and their attributes on long‐term seizure outcome. Methods: We studied the postoperative courses of 492 patients who had completed two or more years of follow‐up after temporal lobe resective epilepsy surgery. We used Kaplan‐Meier survival curves to define long‐term seizure outcome and assessed the predictive value of recurrent seizure characteristics on the outcome by univariate and multivariate proportional hazards regression models. Key Findings: In our patients, seizure recurrences during the first postoperative year, irrespective of the attributes of recurrent seizures (such as provoked vs. unprovoked, and timing and number of recurrences), imparted fourfold to sevenfold increased hazards for continued seizures beyond the first postoperative year. Although patients with complex partial seizures with or without secondary generalized tonic–clonic seizures (CPS/GTCS) had a sixfold increased risk, those with auras alone had only a borderline risk for seizures beyond the first postoperative year. In the multivariate model, CPS/GTCS as the predominant seizure type and three or more seizure recurrences during the first postoperative year independently predicted unfavorable long‐term seizure outcome. Significance: Our study provides valuable information that is helpful in prognosticating and counseling patients, and in making rational decisions on the withdrawal of antiepileptic drugs following surgery. Our findings enhance the general understanding of the etiopathogenesis of surgical failure.     

Age-dependent seizure semiology in temporal lobe epilepsy

OBJECTIVE: To examine the effects of age on different aspects of temporal lobe seizure semiology. METHODS: We performed a video analysis of 605 archived seizures from 155 consecutive patients (age 10 months to 49 years) selected by seizure freedom after temporal lobectomy. Eighty patients had hippocampal sclerosis (HS). Beside semiological seizure classification, we assessed age dependency of several axes of seizure semiology: (1) aura, (2) number of different lateralizing signs, occurrence of ictal (3) emotional signs, (4) autonomic symptoms, (5) automatisms, and (6) secondary generalization as well as (7) the ratio of motor seizure components. RESULTS: From the 155 patients, 117 reported aura, 39 had ictal emotional signs, 51 had autonomic symptoms, 130 presented automatisms, while 18 patients showed secondary generalization at least once during their seizures. Altogether 369 (median: 2/patient) different lateralizing signs were recorded. Frequency of HS (p < 0.001), ictal automatisms (p < 0.001), secondary generalization (p = 0.014), number of different lateralizing signs (p < 0.001) increased while the ratio of motor seizure component (p = 0.007) decreased by age. Auras, emotional symptoms, and autonomic signs occurred independently of patients' ages. Hippocampal sclerosis adjusted linear models revealed that the frequency of automatisms and secondarily generalized seizures as well as the number of different lateralizing signs are HS-independent significant variables. CONCLUSION: Our findings support that brain maturation significantly influences the evolution of some important aspects (motor seizures, lateralizing signs) of temporal lobe seizure semiology. Conversely, other aspects (aura, emotional, and autonomic signs) are independent of the maturation process. This is the first report investigating age dependency of epileptic seizure semiology comparing all age groups.