Predictive factors of postoperative outcome in the elderly after resective epilepsy surgery

OBJECTIVE

To evaluate the efficiency of resective epilepsy surgery (RES) in patients over 50 years and determine prognostic factors.

RESULTS

Over the 147 patients over 50 years (54.9±3.8 years [50-69]) coming from 8 specialized French centres for epilepsy surgery, 72.1%, patients were seizure-free and 91.2% had a good outcome 12 months after RES. Seizure freedom was not associated with the age at surgery or duration of epilepsy. In multivariate analysis, seizure freedom was associated with MRI and neuropathological hippocampal sclerosis (HS) (P=0.009 and P=0.028 respectively), PET hypometabolism (P=0.013), temporal epilepsy (P=0.01). On the contrary, the need for intracranial exploration was associated with a poorer prognosis (P=0.001). Postoperative number of antiepileptic drugs was significantly lower in the seizure-free group (P=0.001). Neurological adverse event rate after surgery was 21.1% and 11.7% of patients had neuropsychological adverse effects overall transient.

CONCLUSIONS

RES is effective procedure in the elderly. Even safe it remains at higher risk of complication and population should be carefully selected. Nevertheless, age should not be considered as a limiting factor, especially when good prognostic factors are identified.

Effect of meditation on intracerebral EEG in a patient with temporal lobe epilepsy: A case report

Meditation has been deemed a miracle cure for a wide range of neurological disorders. However, it is unclear whether meditation practice would be beneficial for patients suffering from epilepsy. Here we report on the comparison of the effects of focused-attention meditation and a control task on electroencephalographic (EEG) activity in a patient undergoing stereoencephalographic (SEEG) investigation for drug-resistant epilepsy. The patient routinely practiced focused-attention meditation and reported that she found it beneficial. During the SEEG investigation, intracerebral EEG data were recorded during meditation as well as during mind-wandering task. The EEG data were analyzed for type of electrical activity (labeled) by two expert epileptologists. We found that the proportion of EEG segments containing activity classified as interictal epileptiform discharges (IEDs; abnormal electrical activity that occurs between seizures) increased significantly during meditation practice. Although the finding was surprising, this increase in IEDs may not correlate with an increase in seizure frequency, and the patient might still benefit from practicing meditation. The finding does, however, warrant further studies on the influence of meditation on epileptic activity.

Etiological assessment of status epilepticus

Status epilepticus (SE) is a potentially serious condition that can affect vital and functional prognosis and requires urgent treatment. Etiology is a determining factor in the patient's functional outcome and in almost half of all cases justifies specific treatment to stop progression. Therefore, identifying and addressing the cause of SE is a key priority in SE management. However, the etiology can be difficult to identify among acute and remote causes, which can also be multiple and interrelated. The most common etiologies are the discontinuation of antiepileptic medication in patients with a prior history of epilepsy, and acute brain aggression in cases of new onset SE (cerebrovascular pathologies are the most common). The list of remaining possible etiologies includes heterogeneous pathological contexts. Refractory SE and especially New-Onset Refractory Status Epilepticus (NORSE) lead to an extension of the etiological assessment in the search for encephalitis of autoimmune or infectious origin in adults and in children, as well as a genetic pathology in children in particular. This is an overview of current knowledge of SE etiologies and a pragmatic approach for carrying out an etiological assessment based on the following steps: - Which etiological orientation is identified according to the field and clinical presentation?; - Which etiologies to look for in an inaugural SE?; - Which first-line assessment should be carried out? The place of the biological, EEG and imaging assessment is discussed; - Which etiologies to look for in case of refractory SE?

[Cost-effectiveness of epilepsy surgery in a cohort of patients with medically intractable partial epilepsy--preliminary results]

OBJECTIVE

Patients with medically intractable epilepsy are potential candidates for surgery if the epileptogenic tissue is localized and resectable. Surgical therapy can eliminate seizures but is very expensive. We followed a prospective adult cohort of intractable epileptic patients in order to perform a cost-effectiveness analysis.

POPULATION AND METHODS

Adult patients with a suspected partial medically intractable and operable epilepsy were eligible for evaluation, explorations and/or surgery. Clinical and economical data were collected at the inclusion and every 6 months over at least two years. Two patient groups were analyzed: some underwent a surgery, others did not. Clinical data were compared between both groups. As the data collection was not yet complete, we compared the surgery to a continuation of the preoperative medical management in a cost-effectiveness analysis. Direct medical and nonmedical costs were evaluated according to a societal perspective. The effectiveness was defined as one year without seizure. We assessed the incremental cost-effectiveness ratio (ICER) for the first two years after the surgery. We also modeled long-term costs and effectiveness and extrapolated the results over the patients' lifetime with a Markov model. We computed the ICER and performed a sensitivity analysis. Indirect costs were measured in physical units and intangible costs were assessed with quality-of-life measures (QOLIE-31, SEALS). Data were compared before and after surgery.

RESULTS

Among the 286 patients included, 119 did not enter in the analysis: 7 were not eligible, 44 not operable, 31 did not present a follow-up, 37 still underwent exams. Finally, 89 underwent a surgical treatment, and 78 were medically treated. Disease was more severe in surgical patients than in medical patients: seizures frequency, depressive disorders and cognitive impairment were greater. One year after the surgery, 83% patients were seizure free. During the year before inclusion and the year after surgery, direct costs were mainly due to hospitalization. During the second year after surgery, the cost of antiepileptic drugs predominated. One additional year without seizure costs 23 531 euro one year after surgery and 9533 euro two years after surgery. In a long-term perspective, the surgery became cost-effective between 7 and 8 years after the surgery.

CONCLUSION

Surgical therapy is a cost-effective treatment in a middle-term even without indirect costs consideration.

[What is the role of neuropsychological testing in the investigation and management of pharmacologically intractable partial epilepsy?]

Neuropsychological testing is an integral part of investigation and management of pharmacologically intractable epilepsy. Patients often complain of cognitive difficulties, in particular memory disturbances. A review of the literature demonstrates that correlations between subjective memory difficulties and objective memory deficits are often poor with mood correlating more consistently with subjective complaints. Nevertheless, objective memory difficulties are often found, especially in patients with temporal lobe epilepsy. Many factors can contribute to cognitive difficulties in patients with pharmacoresistant partial epilepsy. These include brain pathology that may be the cause or the consequence of chronic seizures (or both), physiological brain dysfunction due to epileptic activity and effects of antiepileptic medications. We review some of the abundant relevant literature. Neuropsychological evaluation is routinely used in pre-surgical evaluations of patients and cognitive dysfunction has some degree of correlation with lateralization and localization of epileptic activity, thus helping to determine a surgical strategy. The goal of seizure control is tempered with an assessment of the potential cognitive loss resulting from resective surgery. A number of studies have addressed postoperative neuropsychological findings and it is universally recognized that patients who have high levels of cognitive functioning in the areas targeted for resection (for instance verbal memory in dominant temporal lobe) show the greatest functional loss following surgery. More selective surgery probably results in some level of preservation of cognitive function.

[What is the current role of a Wada test in the pre-surgical work-up of pharmacologically intractable epilepsy in adults?]

Juhn Wada developed a test while in Montreal designed to definitively confirm hemispheric lateralization of speech in candidates for surgical treatment of epilepsy. By unilateral intra-carotid administration of a bolus of a general anesthetic, classically sodium amobarbital, function can be tested in the non-injected hemisphere, while the injected side is dysfunctional. The test has been expanded to test memory functions in the hemisphere (temporal lobe) contralateral to expected surgery (memory reserve) in the hope of contra-indicating surgery that may result in global amnestic syndromes (patient HM). Conversely, risk of material-specific memory loss following surgery can be assessed by testing memory in the hemisphere/temporal lobe to be operated ("functional adequacy"). Memory dysfunction, when concordant with EEG seizure onset and chosen side of temporal lobe surgery has also been shown to correlate with favourable post-operative seizure outcome. Nevertheless, the test remains invasive, requiring an angiogramme. Non-invasive alternatives such as fMRI and PET and their reported reliability compared to a Wada test are discussed. A world-wide shortage of amobarbital has led to the use of some other anesthetic agents. Overall, the indications for the test and the manner in which it is performed vary greatly from one institution to the next. It is used almost systematically in some institutions and very rarely in others. Future perspectives are discussed.

[Rhino-cerebral fungal infection successfully treated with supplementary hyperbaric oxygen therapy]

Rhino-cerebral fungal infections are rare and difficult disorders to cure. We report the case of a woman presenting a left trigeminal neuralgia complicated by ophthalmoplegia and blindness. MRI demonstrated a lesion of the left orbital apex with extension into the cavernous sinus. Fungal infiltration (aspergillosis or mucormycosis), was seen on biopsy. High-dose liposomal Amphotericin B (5mg/kg/day) for six weeks was unsuccessful. Adjunctant hyperbaric oxygen therapy led to clinical and radiological improvement. Hyperbaric oxygen therapy is discussed in the medical management of rhino-cerebral yeast abscesses.

Asymptomatic cerebral embolic signals in patients with acute cerebral ischaemia and severe aortic arch atherosclerosis

Severe aortic arch atheroma (AAA) is a strong risk factor for ischaemic stroke, but it is unclear whether AAA is a source of cerebral emboli or simply a marker of cerebral atherosclerosis. The purpose of this study was to find out the prevalence of asymptomatic cerebral embolic signals (ES) in patients with acute cerebral ischaemia, AAA and no other potential source of cerebral embolism. Forty patients with anterior circulation ischaemic stroke or transient ischaemic attack (TIA) were prospectively studied using transesophageal echocardiography (TEE) and transcranial Doppler (TCD) scanning within seven days of symptom onset. Patients with a cardiac source of embolism or carotid stenosis > 50% were excluded. ES were detected in 14.3% (2/14) of patients with AAA > or = 4 mm and in no patients with AAA < 4 mm or no AAA (p=0.14). The findings suggest that ES may be associated with severe AAA but their prevalence is low in this setting.

Evaluation of new online automated embolic signal detection algorithm, including comparison with panel of international experts

BACKGROUND AND PURPOSE

The clinical application of Doppler detection of circulating cerebral emboli will depend on a reliable automated system of embolic signal detection; such a system is not currently available. Previous studies have shown that frequency filtering increases the ratio of embolic signal to background signal intensity and that the incorporation of such an approach into an offline automated detection system markedly improved performance. In this study, we evaluated an online version of the system. In a single-center study, we compared its performance with that of a human expert on data from 2 clinical situations, carotid stenosis and the period immediately after carotid endarterectomy. Because the human expert is currently the "gold standard" for embolic signal detection, we also compared the performance of the system with an international panel of human experts in a multicenter study.

METHODS

In the single-center evaluation, the performance of the software was tested against that of a human expert on 20 hours of data from 21 patients with carotid stenosis and 18 hours of data from 9 patients that was recorded after carotid endarterectomy. For the multicenter evaluation, a separate 2-hour data set, recorded from 5 patients after carotid endarterectomy, was analyzed by 6 different human experts using the same equipment and by the software. Agreement was assessed by determining the probability of agreement.

RESULTS

In the 20 hours of carotid stenosis data, there were 140 embolic signals with an intensity of > or =7 dB. With the software set at a confidence threshold of 60%, a sensitivity of 85.7% and a specificity of 88.9% for detection of embolic signals were obtained. At higher confidence thresholds, a specificity >95% could be obtained, but this was at the expense of a lower sensitivity. In the 18 hours of post-carotid endarterectomy data, there were 411 embolic signals of > or =7-dB intensity. When the same confidence threshold was used, a sensitivity of 95.4% and a specificity of 97.5% were obtained. In the multicenter evaluation, a total of 127 events were recorded as embolic signals by at least 1 center. The total number of embolic signals detected by the 6 different centers was 84, 93, 108, 92, 63, and 78. The software set at a confidence threshold of 60% detected 90 events as embolic signals. The mean probability of agreement, including all human experts and the software, was 0.83, and this was higher than that for 2 human experts and lower than that for 4 human experts. The mean values for the 6 human observers were averaged to give P=0.84, which was similar to that of the software.

CONCLUSIONS

By using the frequency specificity of the intensity increase occurring with embolic signals, we have developed an automated detection system with a much improved sensitivity. Its performance was equal to that of some human experts and only slightly below the mean performance of a panel of human experts

Validity of diagnosis using the French translation of the semi-structured interview for seizure classification

PURPOSE

The purpose of this study was to assess the acceptability and validity of the French cross-cultural translation of a semistructured interview for seizure classification (SISC). We used the first revised version, the original of which was validated in 1990.

METHODS

We administered the French SISC to a sample of 67 adults older than 15 years, comprising 17 controls and 50 patients with epilepsy (without provoked or isolated seizures). A cross-cultural translation was made from American English into French. Medical records were reviewed by epileptologists, who classified seizures, syndromes, and risk factors in accordance with the International League Against Epilepsy (ILAE) classifications. Agreement between interview- and physician-based diagnoses was assessed with a kappa coefficient (kappa) at each level of the recognized schemes for the classification of seizures (both broad and specific categories), syndromes, and risk factors.

RESULTS

The sensitivity of the French SISC in diagnosing an epileptic seizure was 100%, with a specificity of 94%. Interview-based diagnoses agreed with those of physicians in 90% of patients for broad seizure categories [i.e., generalized or focal in origin (kappa = 0.74)]. When diagnoses agreed on focal origin, the agreement on seizure types-simple or complex-was 91% (kappa = 0.84). Among generalized seizures, the agreement was 73% (kappa = 0.60). Agreement on epilepsy syndromes was excellent for generalized epilepsy but moderate for focal epilepsy. Agreement on identified risk factors was 93%.

CONCLUSIONS

The kappa coefficients demonstrated a good level of reliability. These results support the acceptability of this type of interview and the validity of the French version of the SISC.

Microembolic signals and risk of early recurrence in patients with stroke or transient ischemic attack

BACKGROUND AND PURPOSE

Asymptomatic microembolic signals (MES) can be demonstrated in patients with cerebral ischemia using transcranial Doppler (TCD) ultrasonographic monitoring of the middle cerebral artery. However, the clinical relevance of MES remains uncertain. The purpose of this study was to estimate the independent contribution of microembolism to the risk of early ischemic recurrence (EIR) in patients with stroke or transient ischemic attack (TIA) of presumed arterial origin.

METHODS

We studied the incidence of EIR in 73 consecutive patients with carotid stroke or TIA in whom TCD scanning of the symptomatic middle cerebral artery was performed within 7 days from the onset of symptoms. Patients with a potential cardiac source of embolism were excluded from the study.

RESULTS

Eight patients had EIR during a mean+/-SD follow-up of 10+/-8 days. The incidence of EIR was 4.3 per 100 patient-days in patients with MES and only 0.5 per 100 patient-days in patients without MES. The presence of MES was a significant predictor of EIR after adjustment for the presence of carotid stenosis or aortic arch atheroma, antiplatelet therapy during follow-up, and other potential confounding variables (relative risk, 8.7; 95% confidence interval, 2 to 38.2; P=0.0015).

CONCLUSIONS

Microembolism is a significant independent predictor of EIR in patients with stroke or TIA of presumed arterial origin.

Cerebral microembolism in patients with stroke or transient ischaemic attack as a risk factor for early recurrence

The incidence of early recurrence in 32 patients who had had a transient ischaemic attack or stroke in the anterior circulation was studied. Patients with a potential cardiac source of embolism were excluded from the study. All patients had transcranial Doppler (TCD) monitoring of the symptomatic middle cerebral artery for microembolic signal detection within seven days from the onset of symptoms. Four patients had early recurrence during a mean follow up of 15 (SD11) days. All early recurrences occurred in the same arterial territory as the initial ischaemic event. Three of the four patients with early recurrence had prior microembolic signals. The incidence of early recurrence was 50% (3/6) in patients with microembolic signals and 3.8% (1/26) in patients without microembolic signals (P=0.02). The findings suggest that TCD monitoring of patients with recent cerebral ischaemia of presumed arterial origin allows recognition of a subset of patients at high risk for early recurrence.

Asymptomatic cerebral embolic signals in patients with carotid stenosis. Correlation with appearance of plaque ulceration on angiography

BACKGROUND AND PURPOSE

Asymptomatic cerebral emboli may be detected in patients with carotid stenosis by transcranial Doppler ultrasonography of the middle cerebral artery (MCA). The aim of this study was to determine the angiographic correlates of such embolic signals.

METHODS

Doppler signals from 48 MCAs in 26 patients with carotid stenosis that was either symptomatic (n = 20) or asymptomatic (n = 6) were recorded for 40 minutes. The grade of carotid stenosis and the ulcerated or nonulcerated appearance of the plaque were assessed using the criteria of the North American Symptomatic Carotid Endarterectomy Trial.

RESULTS

Embolic signals were detected in 8 MCAs from 7 patients; 4 (50%) of these MCAs were clinically symptomatic compared with 16 (40%) without embolic signal. Although there was a trend toward more severe stenosis in the cases with embolic signals, this was not significant (mean +/- SD, 67 +/- 29% versus 55 +/- 36%). In contrast, an image of ulceration was found on ipsilateral carotid angiography in 5 cases (63%) with embolic signals and in only 9 cases (23%) without embolic signals (odds ratio, 5.74; 95% confidence interval, 1.15 to 28.79, by multivariate regression analysis).

CONCLUSIONS

This study demonstrates that the occurrence of embolic signals in patients with carotid stenosis is associated with the appearance of plaque ulceration on angiography.