Clinicopathological associations in temporal lobe epilepsy patients utilising the current ILAE focal cortical dysplasia classification

Johnson, Alexandra; Sugo, Ella; Barreto, Daniela Veit; Cunningham, Anne M.; Hiew, Chee-Chung; Lawson, John A.; Somerville, Ernest; Connolly, Anne M.; Bye, Annie

doi:10.1016/j.eplepsyres.2014.06.013

Cited by 25 publications

(20 citation statements)

References 28 publications

(47 reference statements)

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“…29 Clinical, neurophysiological, neuroimaging data, presurgical workup, and outcome are remarkably similar, as if the associated FCD represents a "predisposing" element but not the sole or main cause of drug-resistant epilepsy. Few studies have analyzed the FCD type III subcategories, 29,[41][42][43][44] and further information is needed to assess their role in epilepsy onset and long-term expression.…”

Section: Discussionmentioning

confidence: 99%

Diagnostic methods and treatment options for focal cortical dysplasia

et al. 2015

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SUMMARYOur inability to adequately treat many patients with refractory epilepsy caused by focal cortical dysplasia (FCD), surgical inaccessibility and failures are significant clinical drawbacks. The targeting of physiologic features of epileptogenesis in FCD and colocalizing functionality has enhanced completeness of surgical resection, the main determinant of outcome. Electroencephalography (EEG)-functional magnetic resonance imaging (fMRI) and magnetoencephalography are helpful in guiding electrode implantation and surgical treatment, and high-frequency oscillations help defining the extent of the epileptogenic dysplasia. Ultra high-field MRI has a role in understanding the laminar organization of the cortex, and fluorodeoxyglucose-positron emission tomography (FDG-PET) is highly sensitive for detecting FCD in MRI-negative cases. Multimodal imaging is clinically valuable, either by improving the rate of postoperative seizure freedom or by reducing postoperative deficits. However, there is no level 1 evidence that it improves outcomes. Proof for a specific effect of antiepileptic drugs (AEDs) in FCD is lacking. Pathogenic mutations recently described in mammalian target of rapamycin (mTOR) genes in FCD have yielded important insights into novel treatment options with mTOR inhibitors, which might represent an example of personalized treatment of epilepsy based on the known mechanisms of disease. The ketogenic diet (KD) has been demonstrated to be particularly effective in children with epilepsy caused by structural abnormalities, especially FCD. It attenuates epigenetic chromatin modifications, a master regulator for gene expression and functional adaptation of the cell, thereby modifying disease progression. This could imply lasting benefit of dietary manipulation. Neurostimulation techniques have produced variable clinical outcomes in FCD. In widespread dysplasias, vagus nerve stimulation (VNS) has achieved responder rates >50%; however, the efficacy of noninvasive cranial nerve stimulation modalities such as transcutaneous VNS (tVNS) and noninvasive (nVNS) requires further study. Although review of current strategies underscores the serious shortcomings of treatment-resistant cases, initial evidence from novel approaches suggests that future success is possible.

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Section: Discussionmentioning

confidence: 99%

Diagnostic methods and treatment options for focal cortical dysplasia

et al. 2015

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“…[2][3][4][5][6][7][8][9] The value of this study is represented by the large number of enrolled patients and the relationship between seizure outcome and FCD types. However, it is our opinion that considering FCD independently of the site involved (left or right hemisphere, critical cerebral areas) and of the different surgical approaches (ranging from lesionectomy to multilobar lobectomy) represents a notable bias.…”

Section: To the Editorsmentioning

confidence: 99%

Commentary on long‐term seizure outcome in 211 patients with focal cortical dysplasia

2015

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Commentary on long-term seizure outcome in 211 patients with focal cortical dysplasia To the Editors:We have read with great interest the paper by Fauser et al.,1 titled "Long-term seizure outcome in 211 patients with focal cortical dysplasia. "This study is a valuable effort to identify the predictors of long-term seizure control in epilepsy surgery for focal cortical dysplasia (FCD).As the authors stated, FCD represents a common architectural or cytoarchitectural cortical disorder underlying pharmacoresistant epilepsy.We agree with the authors about the importance in epilepsy surgery of both identifying the factors predicting seizure outcome and relating seizure outcome to histopathologic diagnosis. 2-9The value of this study is represented by the large number of enrolled patients and the relationship between seizure outcome and FCD types. However, it is our opinion that considering FCD independently of the site involved (left or right hemisphere, critical cerebral areas) and of the different surgical approaches (ranging from lesionectomy to multilobar lobectomy) represents a notable bias. We think that this methodology likely may have contributed to masking of some important differences among FCD types I, II, and IIIa, thereby preventing the acquisition of statistically significant differences regarding seizure freedom.In our temporal lobe epilepsy surgery experience, the most common pathology in adult patients has been FCD type IIIa. 3,7 Furthermore, according to the literature, 9,10 the patients with hippocampal sclerosis (HS) associated with FCD type I (now classified as FCD IIIa) show a seizure outcome similar to that of patients with isolated HS (84% Engel class I vs. 82%) and better than patients with isolated FCD type I (63% Engel class I). 3,7,[10][11][12] Our results indicate also that cases of associated FCD type II are not as rare as previously reported, such as for instance, the association between FCD type II and other structural abnormalities, namely, HS or epilepsy-associated tumors (EATs). These aspects may prove a useful parameter for more precise histopathologic classification that may help to clarify the relationship with seizure outcome and the implications for pathogenetic epileptogenic mechanisms.Finally, a methodologic approach utilized for other brain pathologies, such as cerebral tumor or vascular lesions, will be unavoidable due to the continuous remarkable advances in pathologic knowledge of underlying epilepsy lesions.This unifying methodologic approach aims to relate the surgical results to the precise type of pathology, the site of the lesion, and the surgical strategy utilized. We think that this approach will help epilepsy surgery to come out of a long-lasting status of indeterminateness and promote a greater spread and application of the practice. DISCLOSUREWe have no conflict of interest in publishing this letter. We confirm that we have read the Journal's position on issues involved in ethical publication and affirm that this report is consistent with those guidelines.

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“…As a tertiary hospital mainly for adult patients, low recruitment of FCD cases with younger age in the present study might also contribute to lower inclusion of FCD I cases as well. Focal seizure with VEEG discharges originating from unilateral region was the most common seizure type presented in each FCD subtype, which could be attributed to "focal origin character" of FCD [4]. In addition, patients diagnosed of tumor without associated FCD had shorter seizure duration than tumor with FCD IIIb.…”

Section: Discussionmentioning

confidence: 91%

“…Focal cortical dysplasia (FCD) is frequently associated with drug-resistant epilepsy in both children and adults [1]. It is reported with higher recurrence rate after epilepsy surgeries compared to other etiologies such as neoplasm and vascular malformations, which raises the need for adopted surgical strategies for FCD [2][3][4][5]. In addition, the clinical manifestation, post-surgical short-term and long-term outcome of patients varies between different FCD subtypes [6][7][8].…”

Section: Introductionmentioning

confidence: 99%