Cost of pre-surgical evaluation for epilepsy surgery: A single-center experience.

OBJECTIVE: To estimate the cost and time taken to evaluate adults with drug-resistant focal epilepsy for potentially curative surgery. METHODS: We reviewed data on 100 consecutive individuals at a tertiary referral center evaluated for epilepsy surgery in 2017. The time elapsed between referral and either surgery or a definitive decision not to progress was measured. National Health Service tariffs applicable to our setting were used to estimate the total cost of evaluation for individuals following different routes through the pre-surgical pathway. After surgery, self-reported seizure freedom rates were obtained from each individual to assess the approximate cost of pre-surgical evaluation per additional person seizure-free. RESULTS: Of 100 individuals evaluated, 27 had surgery, 63 had a definitive decision not to have surgery, and ten were awaiting further investigations. The median duration of the pre-surgical evaluation was 29.7 months (IQR 18.6-44.1 months), with a median cost per person of £9138 (IQR £6984-£14,868). Those who proceeded to Stage Two investigations (including fluorodeoxyglucose positron emission tomography, ictal single-photon emission computerized tomography and intracranial electroencephalography) had a higher cost and extended evaluation length. After a median of 3.1 (IQR 2.3-3.7) years, 15/27 people who had surgery were seizure-free. This equated to an approximate cost of £123,500 spent per additional person seizure-free. CONCLUSION: Pre-surgical evaluation is long and costly, particularly for those who require icEEG. For those with drug-resistant focal epilepsy, surgery is, however, associated with a greater chance of seizure freedom. The suitability and risk-benefit ratio of surgery should be considered at each step of the pre-surgical pathway.

Independent components of human brain morphology.

Quantification of brain morphology has become an important cornerstone in understanding brain structure. Measures of cortical morphology such as thickness and surface area are frequently used to compare groups of subjects or characterise longitudinal changes. However, such measures are often treated as independent from each other. A recently described scaling law, derived from a statistical physics model of cortical folding, demonstrates that there is a tight covariance between three commonly used cortical morphology measures: cortical thickness, total surface area, and exposed surface area. We show that assuming the independence of cortical morphology measures can hide features and potentially lead to misinterpretations. Using the scaling law, we account for the covariance between cortical morphology measures and derive novel independent measures of cortical morphology. By applying these new measures, we show that new information can be gained; in our example we show that distinct morphological alterations underlie healthy ageing compared to temporal lobe epilepsy, even on the coarse level of a whole hemisphere. We thus provide a conceptual framework for characterising cortical morphology in a statistically valid and interpretable manner, based on theoretical reasoning about the shape of the cortex.

A European questionnaire survey on epilepsy monitoring units' current practice for postoperative psychogenic nonepileptic seizures' detection.

BACKGROUND: In cases undergoing epilepsy surgery, postoperative psychogenic nonepileptic seizures (PNES) may be underdiagnosed complicating the assessment of postsurgical seizures' outcome and the clinical management. We conducted a survey to investigate the current practices in the European epilepsy monitoring units (EMUs) and the data that EMUs could provide to retrospectively detect cases with postoperative PNES and to assess the feasibility of a subsequent postoperative PNES research project for cases with postoperative PNES. METHODS: We developed and distributed a questionnaire survey to 57 EMUs. Questions addressed the number of patients undergoing epilepsy surgery, the performance of systematic preoperative and postoperative psychiatric evaluation, the recording of sexual or other abuse, the follow-up period of patients undergoing epilepsy surgery, the performance of video-electroencephalogram (EEG) and postoperative psychiatric assessment in suspected postoperative cases with PNES, the existence of electronic databases to allow extraction of cases with postoperative PNES, the data that these bases could provide, and EMUs' interest to participate in a retrospective postoperative PNES project. RESULTS: Twenty EMUs completed the questionnaire sheet. The number of patients operated every year/per center is 26.7 ( ±â€¯19.1), and systematic preoperative and postoperative psychiatric evaluation is performed in 75% and 50% of the EMUs accordingly. Sexual or other abuse is systematically recorded in one-third of the centers, and the mean follow-up period after epilepsy surgery is 10.5 ±â€¯7.5 years. In suspected postoperative PNES, video-EEG is performed in 85% and psychiatric assessment in 95% of the centers. An electronic database to allow extraction of patients with PNES after epilepsy surgery is used in 75% of the EMUs, and all EMUs that sent the sheet completed expressed their interest to participate in a retrospective postoperative PNES project. CONCLUSION: Postoperative PNES is an underestimated and not well-studied entity. This is a European survey to assess the type of data that the EMUs surgical cohorts could provide to retrospectively detect postoperative PNES. In cases with suspected PNES, most EMUs perform video-EEG and psychiatric assessment, and most EMUs use an electronic database to allow extraction of patients developing PNES.