The Surgical and Cognitive Outcomes of Focal Cortical Dysplasia

Evaluations of artificial intelligence and machine learning algorithms in neurodiagnostics

This article evaluates the ethical implications of utilizing artificial intelligence (AI) algorithms in neurological diagnostic examinations. Applications of AI technology have been utilized to aid in the determination of pharmacological dosages of gadolinium for brain lesion detection, localization of seizure foci, and the characterization of large vessel occlusion in ischemic stroke patients. Multiple subtypes of AI/machine learning (ML) algorithms are analyzed, as AI-assisted neurology utilizes supervised, unsupervised, artificial neural network (ANN), and deep neural network (DNN) learning models. As ANN and DNN analyses can be applied to data with an unknown clinical diagnosis, these algorithms are evaluated according to Bayesian statistical analyses. Bayesian neural network analyses are incorporated, as these algorithms indicate that the predictive accuracy and model performance are dependent upon accurate configurations of the model's hyperparameters and neural inputs. Thus, mathematical evaluations of AI algorithms are comprehensively explored to examine their clinical utility, as underperformance of AI/ML models may have deleterious consequences that affect patient outcomes due to misdiagnosis and false-negative test results.

To explore the potential mechanisms of cognitive impairment in children with MRI-negative pharmacoresistant epilepsy due to focal cortical dysplasia: A pilot study from gray matter structure view

Objectives

To investigate the characteristics of brain structure in children with focal cortical dysplasia (FCD)-induced pharmacoresistant epilepsy, and explore the potential mechanisms of cognitive impairment from the view of gray matter alteration.

Methods

25 pharmacoresistant pediatric patients with pathologically confirmed focal cortical dysplasia (FCD), and 25 gender-matched healthy controls were included in this study. 3.0T MRI data and intelligence tests using the Wechsler Intelligence Scale for Children-Forth Edition (WISC-IV) were generated for all subjects. Voxel-based morphometry (VBM)-diffeomorphic anatomical registration through exponentiated lie algebra (DARTEL) and surface-based morphometry (SBM) analyses were performed to analyze gray matter volume and cortical structure. Two-sample t-tests were used to compare the differences in gray matter volume (P＜0.05, FWE) and cortical thickness (P＜0.001, FWE) between the two groups. Also, the Spearman rank correlation analyses were employed to determine the relationship between structural alterations and neuropsychological results.

Results

The WISC-IV scores of the FCD group were significantly lower than those of the HC group in terms of full-scale intelligence quotient (FSIQ), verbal comprehension index (VCI), perceptual reasoning index (PRI), working memory index (WMI), and processing speed index (PSI) (all P＜0.01). Compared with the HC group, in the FCD group, the gray matter volume (GMV) reduced significantly in the left cerebellum_8, cerebellum_Crus2, and bilateral thalamus (P＜0.05, FWE); the GMV increased in the bilateral medial frontal gyrus, right precuneus, and left inferior temporal gyrus (P＜0.05, FWE), and the cortical thickness increased in the bilateral frontal, parietal, and temporal areas (P＜0.001, FWE). Correlation analyses showed that the age of seizure onset had positive correlations with the WISC-IV scores significantly. Meanwhile, the cortex thicknesses of the left pars opercularis gyrus, left middle temporal gyrus, and right inferior temporal gyrus had negative correlations with the WISC-IV scores significantly.

Conclusion

FCD patients showed subtle structural abnormalities in multiple brain regions, with significant involvement of the primary visual cortex and language function cortex. And we also demonstrated a crucial correlation between gray matter structural alteration and cognitive impairment.

Patient, parent and carer perspectives surrounding expedited paediatric epilepsy surgery

OBJECTIVE

Most paediatric epilepsies with MRI visible lesions do not respond to antiseizure pharmacotherapy. Such medication resistance, which often takes years to become formally defined, is commonly required for surgical candidacy. Expedited surgical referral at lesional epilepsy diagnosis may result in better seizure, cognitive and developmental prognoses. This study explored the views of patients, parents and carers regarding epilepsy surgery, treatment priorities, and participation in a proposed expedited surgery trial.

METHODS

205 patients, parents and carers (61% UK-based, 26% North American) responded to electronic surveys from February to May 2022. Participants were recruited through social media sites, epilepsy charities and societies. Categorical choice and free-text questions were used to investigate participant perspectives, and Pearson's chi-squared test was utilised to detect meaningful differences amongst respondent subgroups.

RESULTS

Almost 90% of respondents who had experienced epilepsy surgery (either themselves or their child) reported seizure cessation or reduction. Postoperative outcome measures prioritised most frequently were seizure freedom (66%), quality of life (47%), seizure severity (30%), seizure frequency (28%) and independence (27%). Most participants support expedited surgery in suitable patients (65%), with just over half (51%) willing to participate in the proposed trial. Many participants (37%) were undecided, often due to fears surrounding neurosurgery. Subgroup perspectives were broadly similar, with more parents and caregivers favouring expedited surgery compared to patients (p = .016) and more UK-based participants willing to take part in an expedited surgery trial compared to those from North America (p = .01).

CONCLUSIONS

Patients, parents and carers are open to considering expedited surgery for lesional epilepsies and would support a trial exploring this approach. Priorities from treatment were largely similar between participant subgroups, with seizure, quality of life and neuropsychological outcomes ranked highly. Accounting for these preferences will facilitate the delivery of a trial that is patient- and caregiver-focused, enhancing feasibility, satisfaction and benefit for prospective participants.

Awake Surgery for Lesional Epilepsy in Resource-Limited Settings: Case Report and Review of Literature

Epilepsy surgery is a well-established treatment for drug-resistant epilepsy, with awake craniotomy being used in certain cases to remove epileptogenic foci while preserving crucial brain functions. We are presenting the first reported case from Pakistan of a 19-year-old woman who underwent awake epilepsy surgery to treat cortical dysplasia. She had a history of generalized tonic-clonic seizures since her childhood and was referred to our clinic due to an increase in seizure frequency. EEG and MRI identified the epileptogenic focus in the right parieto-temporal region. The patient underwent a neuro-navigation guided awake craniotomy and an excision of the epileptogenic focus in the right parieto-temporal region. The procedure was carried out using a scalp block and dexmedetomidine for conscious sedation, enabling the patient to remain awake throughout the surgery. Intraoperative mapping and electrocorticography were used for complex multidisciplinary care. Post-resection corticography showed no spikes along the resected margins. The patient was discharged without any complications and remained free of symptoms a year after the surgery. Awake epilepsy surgery is a viable option for removing epileptogenic foci while preserving vital cognitive functions. However, it is seldom used in low- and middle-income countries such as Pakistan. The successful outcome of this case underscores the need for greater awareness and availability of epilepsy surgery in resource-limited settings. Cost-effective measures, such as using small subdural strips for intraoperative localization, can be implemented.

Comprehensive multi-omic profiling of somatic mutations in malformations of cortical development

Malformations of cortical development (MCD) are neurological conditions involving focal disruptions of cortical architecture and cellular organization that arise during embryogenesis, largely from somatic mosaic mutations, and cause intractable epilepsy. Identifying the genetic causes of MCD has been a challenge, as mutations remain at low allelic fractions in brain tissue resected to treat condition-related epilepsy. Here we report a genetic landscape from 283 brain resections, identifying 69 mutated genes through intensive profiling of somatic mutations, combining whole-exome and targeted-amplicon sequencing with functional validation including in utero electroporation of mice and single-nucleus RNA sequencing. Genotype-phenotype correlation analysis elucidated specific MCD gene sets associated with distinct pathophysiological and clinical phenotypes. The unique single-cell level spatiotemporal expression patterns of mutated genes in control and patient brains indicate critical roles in excitatory neurogenic pools during brain development and in promoting neuronal hyperexcitability after birth.

Clinical utility of intraoperative electrocorticography for epilepsy surgery: A systematic review and meta-analysis

Despite the widespread use of intraoperative electrocorticography (iECoG) during resective epilepsy surgery, there are conflicting data on its overall efficacy and inability to predict benefit per pathology. Given the heterogeneity of iECoG use in resective epilepsy surgery, it is important to assess the utility of interictal-based iECoG. This individual patient data (IPD) meta-analysis seeks to identify the benefit of iECoG during resective epilepsy surgery in achieving seizure freedom for various pathologies. Embase, Scopus, and PubMed were searched from inception to January 31, 2021 using the following terms: "ecog", "electrocorticography", and "epilepsy". Articles were included if they reported seizure freedom at ≥12-month follow-up in cohorts with and without iECoG for epilepsy surgery. Non-English articles, noncomparative iECoG cohorts, and studies with <10% iECoG use were excluded. This meta-analysis followed the PRISMA 2020 guidelines. The primary outcome was seizure freedom at last follow-up and time to seizure recurrence, if applicable. Forest plots with random effects modeling assessed the relationship between iECoG use and seizure freedom. Cox regression of IPD was performed to identify predictors of longer duration of seizure freedom. Kaplan-Meier curves with log-rank test were created to visualize differences in time to seizure recurrence. Of 7504 articles identified, 18 were included for study-level analysis. iECoG was not associated with higher seizure freedom at the study level (relative risk = 1.09, 95% confidence interval [CI] = 0.96-1.23, p = .19, I²  = 64%), but on IPD (n = 7 studies, 231 patients) iECoG use was independently associated with more favorable seizure outcomes (hazard ratio = 0.47, 95% CI = .23-.95, p = .037). In Kaplan-Meier analysis of specific pathologies, iECoG use was significantly associated with longer seizure freedom only for focal cortical dysplasia (FCD; p < .001) etiology. Number needed to treat for iECoG was 8.8, and for iECoG in FCD it was 4.7. We show iECoG seizure freedom is not achieved uniformly across centers. iECoG is particularly beneficial for FCD etiology in improving seizure freedom.

Post-Surgical Outcome and Its Determining Factors in Patients Operated on With Focal Cortical Dysplasia Type II-A Retrospective Monocenter Study

Purpose: Focal cortical dysplasias (FCDs) are a frequent cause of drug-resistant focal epilepsies. These lesions are in many cases amenable to epilepsy surgery. We examined 12-month and long-term post-surgical outcomes and its predictors including positive family history of epilepsy.

Methods: Twelve-month and long-term outcomes regarding seizure control after epilepsy surgery in patients operated on with FCD type II between 2002 and 2019 in the Epilepsy Center of Bonn were evaluated based on patient records and telephone interviews.

Results: Overall, 102 patients fulfilled the inclusion criteria. Seventy-one percent of patients at 12 months of follow-up (FU) and 54% of patients at the last available FU (63 ± 5.00 months, median 46.5 months) achieved complete seizure freedom (Engel class IA), and 84 and 69% of patients, respectively, displayed Engel class I outcome. From the examined variables [histopathology: FCD IIA vs. IIB, lobar lesion location: frontal vs. non-frontal, family history for epilepsy, focal to bilateral tonic–clonic seizures (FTBTCS) in case history, completeness of resection, age at epilepsy onset, age at surgery, duration of epilepsy], outcomes at 12 months were determined by interactions of age at onset, duration of epilepsy, age at surgery, extent of resection, and lesion location. Long-term post-surgical outcome was primarily influenced by the extent of resection and history of FTBTCS. Positive family history for epilepsy had a marginal influence on long-term outcomes only.

Conclusion: Resective epilepsy surgery in patients with FCD II yields very good outcomes both at 12-month and long-term follow-ups. Complete lesion resection and the absence of FTBTCS prior to surgery are associated with a better outcome.