Identifying epilepsy surgery candidates in the outpatient clinic

Olfactory function in patients with temporal lobe epilepsy; correlation of functional magnetic resonance imaging for olfaction with the laterality of the epileptic focus

The olfactory function shares the same cerebral structures as those involved in the origin and propagation of focal temporal lobe seizures. Likewise, functional magnetic resonance imaging (fMRI) allows the study of olfactory function. This suggests that by quantitatively studying the olfactory function with an olfactory paradigm through fMRI it is possible to identify the functional alteration produced by the epileptic focus. The objective of the present study was to assess the olfactory function in the side of the epileptic focus in patients with mesial temporal lobe epilepsy, using fMRI for smell, and propose a non-invasive diagnostic method for patients candidates to mesial temporal lobe epilepsy surgery.

METHODS

Patients (n = 18) with clinical diagnosis of mesial temporal lobe epilepsy, refractory to pharmacological treatment: 7 patients (38.9%) with non-invasive studies consistent enough to submit them to anterior temporal lobectomy, and 11 (61.1%) patients where focal onset seizures were identified by stereoelectroencephalography (SEEG) on the left temporal lobe in 5 (27.8%) and in both temporal lobes in 2 (11.1%). Patients were evaluated using EEG, MRI, neuropsychological data, and fMRI with olfactory paradigm. Results of the fMRI were compared with the laterality of the epileptic focus determined by intracranial electroencephalogram recordings through stereotactically placed electrodes, and with post-surgical outcome at one year of follow-up.

RESULTS

fMRI showed a lower olfactory activation in 81.8% concordant with unilateral onset seizures. There were significant differences of olfactory fMRI activation between epileptic and non-epileptic foci.

CONCLUSION

Functional magnetic resonance imaging with an olfactory paradigm may be a non-invasive diagnostic tool to determine the laterality of seizure onset in the mesial temporal lobe.

Anxiety and Depression in Adult First Seizure Presentations

OBJECTIVE

To define the prevalence of psychiatric symptoms of anxiety and depression in patients at the time of their first seizure presentation to a neurologist.

METHODS

Our pilot study uses a cohort approach with multimodal data (clinical, social, structural [3T magnetic resonance imaging], and functional [electroencephalogram]). We screened 105 patients referred to the Halifax First Seizure Clinic between 2014 and 2016 and 51 controls. All participants completed two screening questionnaires: Neurological Disorders Depression Inventory for Epilepsy and Generalized Anxiety Disorder 7-Item. After applying the exclusion criteria, the study population consisted of 57 patients with unprovoked first seizure and 31 controls. The prevalence of anxiety and depression was based on cutoff scores of >15 and >14 respectively.

RESULTS

Unprovoked first seizure patients showed higher prevalence of depression (33%) compared with control (6%) with an odds ratio (OR) of 2.75 (95% confidence interval [CI], 0.72-10.5). There was no significant difference in the prevalence of anxiety between control subjects (9.7%) and unprovoked first seizure patients (23%). Subcategory analysis conducted after diagnosis confirmation revealed significantly increased OR of depression in patients diagnosed with new-onset epilepsy (OR, 11.6; 95% CI, 2.1-64.0) and newly diagnosed epilepsy (OR, 20.0; 95% CI,2.2-181), but not first seizure only patients (OR, 2.2; 95% CI,0.28-17.6) compared with control.

CONCLUSIONS

Our study supports a bidirectional relationship between the first seizure and depression. Prevalence rate of depression increased with duration of undiagnosed epilepsy at the time of first clinical assessment.

Long-term surgical results of supplementary motor area epilepsy surgery

OBJECTIVE Supplementary motor area (SMA) epilepsy is a well-known clinical condition; however, long-term surgical outcome reports are scarce and correspond to small series or isolated case reports. The aim of this study is to present the surgical results of SMA epilepsy patients treated at 2 reference centers in Mexico City. METHODS For this retrospective descriptive study (1999-2014), 52 patients underwent lesionectomy and/or corticectomy of the SMA that was guided by electrocorticography (ECoG). The clinical, neurophysiological, neuroimaging, and pathological findings are described. The Engel scale was used to classify surgical outcome. Descriptive statistics, Student t-test, and Friedman, Kruskal-Wallis, and chi-square tests were used. RESULTS Of these 52 patients, the mean age at epilepsy onset was 26.3 years, and the mean preoperative seizure frequency was 14 seizures per month. Etiologies included low-grade tumors in 28 (53.8%) patients, cortical dysplasia in 17 (32.7%) patients, and cavernomas in 7 (13.5%) patients. At a mean follow-up of 5.7 years (range 1-10 years), 32 patients (61%) were classified as Engel Class I, 16 patients (31%) were classified as Engel Class II, and 4 (8%) patients were classified as Engel Class III. Overall seizure reduction was significant (p = 0.001). The absence of early postsurgical seizures and lesional etiology were associated with the outcome of Engel Class I (p = 0.05). Twenty-six (50%) patients had complications in the immediate postoperative period, all of which resolved completely with no residual neurological deficits. CONCLUSIONS Surgery for SMA epilepsy guided by ECoG using a multidisciplinary and multimodality approach is a safe, feasible procedure that shows good seizure control, moderate morbidity, and no mortality.

Sensitivity and specificity of Ankara University Cerebral Dominance Inventory in comparison with the Wada test

We aimed to examine the sensitivity and specificity of the Ankara University Cerebral Dominance Inventory (AUCDI) in determining left cerebral dominance compared with the Wada test. The AUCDI and Wada test were applied to 49 patients referred to Ankara University for epilepsy surgery. Hand, foot and 'total' preference scores were specified according to the results of the inventory. Thirty-eight of the patients had left cerebral dominance and 11 had atypical cerebral dominance for language. 86 % of the patients were right-handed and 43 % were right-footed. When compared with the results of the Wada test, the sensitivity of the AUCDI for each 'total preference', and hand and foot preference was 90, 95 and 50 % and specificity was 46, 46 and 82 %, respectively. The percentage of right-footed patients was low when compared with the other studies. This difference might result from the method used for assessing foot preference by the actual demonstration of the task rather than just asking about the performance. The AUCDI was found to be sensitive in terms of 'total preference' and hand preference, and specific in terms of foot preference for determining the left hemisphere dominance in patients preferring the right side. It was a cheap and noninvasive alternative to the Wada test, appropriate for clinical bedside evaluation.

[Epilepsy surgery--assessment and patient selection]

BACKGROUND

Considerable progress in diagnostic imaging and video EEG monitoring has improved the possibilities of localising the epileptogenic zone of the brain in patients with epilepsy. Despite the fact that epilepsy surgery can therefore be offered to more patients today than previously, relatively few patients are referred for an assessment for surgery. The aim of this review is to provide a brief account of the patient selection procedures and the investigations prior to epilepsy surgery.

METHOD

The review is based on a literature search in PubMed and the personal experiences of the authors in this field.

RESULTS

If the epilepsy does not respond to any kind of pharmacological treatment, and idiopathic generalised epilepsy and pseudoresistance have been ruled out, the patient should be evaluated for surgery. The evaluation is multidisciplinary, and the aim is to localise the epileptogenic zone, which can be identified by both structural and functional abnormalities. It must be determined before the operation whether the zone can be removed without leaving severe neurological or cognitive impairment. The best results after epilepsy surgery are seen in patients with a morphological substrate, particularly temporal lobe epilepsy associated with hippocampal sclerosis.

INTERPRETATION

Epilepsy surgery plays an ever more important role in the treatment of patients with drug resistant seizures. Doctors who treat epileptic patients should refer candidates for surgery at an early stage of the disease.

Video-electroencephalography investigation of ictal alterations of consciousness in epilepsy and nonepileptic attack disorder: practical considerations

The ictal assessment of consciousness is of central importance in the differential diagnosis of epilepsy and nonepileptic attack disorder (NEAD). Long-term video-electroencephalography (video-EEG) is currently considered the gold standard investigative technique for the evaluation of patients with recurrent attacks associated with transient alterations of arousal (responsiveness) and/or awareness (experiential states). This paper offers a concise review focusing on the practical aspects of clinical relevance in the video-EEG diagnostic workout of inpatients with suspected epilepsy or NEAD, as outlined in existing guidelines and recommendations. The reviewed literature implies that both implementation of specific procedures (e.g., activation maneuvers) and interpersonal approach (e.g., monitoring protocols) during video-EEG should be tailored to the individual patient's presentation.

Epilepsy surgery utilization: who, when, where, and why?

PURPOSE OF REVIEW

Using the most recent evidence, we provide an update on epilepsy surgery, focusing on its effectiveness, reasons for underutilization, considerations of candidacy and timing for referral for epilepsy surgery evaluation.

RECENT FINDINGS

The course of illness of epilepsy is being characterized. Well conducted studies describe the patterns of seizure remission and relapse with medical therapy and also in response to epilepsy surgery. Epilepsy surgery is highly effective in selected patients with drug-resistant epilepsy (DRE). The risk-benefit of epilepsy surgery is well known and consistent around the world. However, epilepsy surgery remains underutilized. A randomized controlled trial and Clinical Practice Guidelines (CPGs) supporting epilepsy surgery have had no discernible impact on referral rates for epilepsy surgery evaluation. Criteria and guidelines are being developed for identifying patients who need to be referred for epilepsy surgery evaluation. Quality indicators for epilepsy care now also include the need to consider surgical candidacy every 3 years in DRE. New developments in imaging and neurophysiology promise to help clinicians identify and treat patients more accurately.

SUMMARY

Surgery is effective but underused. Comprehensive interventions to translate evidence to practice in epilepsy surgery are urgently needed.

Early surgical therapy for drug-resistant temporal lobe epilepsy: a randomized trial

CONTEXT

Despite reported success, surgery for pharmacoresistant seizures is often seen as a last resort. Patients are typically referred for surgery after 20 years of seizures, often too late to avoid significant disability and premature death.

OBJECTIVE

We sought to determine whether surgery soon after failure of 2 antiepileptic drug (AED) trials is superior to continued medical management in controlling seizures and improving quality of life (QOL).

DESIGN, SETTING, AND PARTICIPANTS

The Early Randomized Surgical Epilepsy Trial (ERSET) is a multicenter, controlled, parallel-group clinical trial performed at 16 US epilepsy surgery centers. The 38 participants (18 men and 20 women; aged ≥12 years) had mesial temporal lobe epilepsy (MTLE) and disabling seizues for no more than 2 consecutive years following adequate trials of 2 brand-name AEDs. Eligibility for anteromesial temporal resection (AMTR) was based on a standardized presurgical evaluation protocol. Participants were randomized to continued AED treatment or AMTR 2003-2007, and observed for 2 years. Planned enrollment was 200, but the trial was halted prematurely due to slow accrual.

INTERVENTION

Receipt of continued AED treatment (n = 23) or a standardized AMTR plus AED treatment (n = 15). In the medical group, 7 participants underwent AMTR prior to the end of follow-up and 1 participant in the surgical group never received surgery.

MAIN OUTCOME MEASURES

The primary outcome variable was freedom from disabling seizures during year 2 of follow-up. Secondary outcome variables were health-related QOL (measured primarily by the 2-year change in the Quality of Life in Epilepsy 89 [QOLIE-89] overall T-score), cognitive function, and social adaptation.

RESULTS

Zero of 23 participants in the medical group and 11 of 15 in the surgical group were seizure free during year 2 of follow-up (odds ratio = ∞; 95% CI, 11.8 to ∞; P < .001). In an intention-to-treat analysis, the mean improvement in QOLIE-89 overall T-score was higher in the surgical group than in the medical group but this difference was not statistically significant (12.6 vs 4.0 points; treatment effect = 8.5; 95% CI, -1.0 to 18.1; P = .08). When data obtained after surgery from participants in the medical group were excluded, the effect of surgery on QOL was significant (12.8 vs 2.8 points; treatment effect = 9.9; 95% CI, 2.2 to 17.7; P = .01). Memory decline (assessed using the Rey Auditory Verbal Learning Test) occurred in 4 participants (36%) after surgery, consistent with rates seen in the literature; but the sample was too small to permit definitive conclusions about treatment group differences in cognitive outcomes. Adverse events included a transient neurologic deficit attributed to a magnetic resonance imaging-identified postoperative stroke in a participant who had surgery and 3 cases of status epilepticus in the medical group.

CONCLUSIONS

Among patients with newly intractable disabling MTLE, resective surgery plus AED treatment resulted in a lower probability of seizures during year 2 of follow-up than continued AED treatment alone. Given the premature termination of the trial, the results should be interpreted with appropriate caution.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT00040326.