First operation in SPIDER and the path to complete MITICA

The requirements of ITER neutral beam injectors (1 MeV, 40 A negative deuterium ion current for 1 h) have never been simultaneously attained; therefore, a dedicated Neutral Beam Test Facility (NBTF) was set up at Consorzio RFX (Padova, Italy). The NBTF includes two experiments: SPIDER (Source for the Production of Ions of Deuterium Extracted from Rf plasma), the full-scale prototype of the source of ITER injectors, with a 100 keV accelerator, to investigate and optimize the properties of the ion source; and MITICA, the full-scale prototype of the entire injector, devoted to the issues related to the accelerator, including voltage holding at low gas pressure. The present paper gives an account of the status of the procurements, of the timeline, and of the voltage holding tests and experiments for MITICA. As for SPIDER, the first year of operation is described, regarding the solution of some issues connected with the radiofrequency power, the source operation, and the characterization of the first negative ion beam.

Interpreting the dynamic equilibrium during evaporation in a cesium environment

The cesium ovens for the prototype source of the ITER neutral beam injectors are currently tested in the CAesium Test Stand (CATS) facility, with a background pressure of 10^-6 mbar. Different diagnostics are here installed: two Langmuir-Taylor detectors allow us to determine the Cs vapour evaporation rate from the oven and the Cs density at different positions in the vacuum chamber; and laser absorption spectroscopy is used to measure the density integrated over a line of sight and a quartz crystal microbalance to detect the cesium mass deposited in time over a surface. In this paper, we present a model to describe the dynamic equilibrium in the evaporation chamber of CATS with the first oven tested in order to gain information about the Cs sticking coefficient at the walls. The model hence includes sticking and energy accommodation of the Cs atoms to the walls, calculates the flux density at the surfaces, and provides the Cs atom density at any location in the volume. By this model, we simulate the Cs evaporation and the equilibrium density, comparing the modeled results with the experimental data. As a result, a sticking coefficient of 2% is obtained.

Investigation of patient and observer agreement on description of seizures at initial clinical visit

There have been few studies of agreement between seizure descriptions obtained from patients and observers. We investigated 220 patients and observers who completed structured questionnaires about patients’ semiological seizure features at the initial clinical visit. Inter‐rater reliability was assessed using Cohen’s kappa and indices of positive and negative agreement. Patients and observers had excellent agreement on the presence of memory impairment and generalized shaking and stiffness during seizures. In addition, patients under‐reported seizure descriptions more easily observed externally, whereas observers under‐reported change in patient location at seizure end. These findings may guide interpretation of clinical histories obtain in epilepsy care.

Migraine comorbidity and cognitive performance in patients with focal epilepsy

BACKGROUND

Migraine and epilepsy are comorbid conditions. While it is well known that epilepsy can have an impact on cognitive abilities, there is conflicting evidence in the literature on the relationship between migraine and cognitive function. The aim of this study was to assess whether migraine comorbidity in patients with newly diagnosed focal epilepsy is associated with cognitive dysfunction.

METHODS

This is a post hoc analysis of data prospectively collected for the Human Epilepsy Project (HEP). There were 349 participants screened for migraine with the 13 questions used in the American Migraine Prevalence and Prevention (AMPP) study. Participants were also screened for depression using the Neurological Disorder Depression Inventory for Epilepsy (NDDI-E) and the Center for Epidemiologic Studies Depression Scale (CES-D) and for anxiety using the Generalized Anxiety Disorder-7 (GAD-7) scale. Cognitive performance was assessed with the Cogstate Brief Battery and Aldenkamp-Baker Neuropsychological Assessment Schedule (ABNAS).

RESULTS

About a fifth (21.2%) of patients with a new diagnosis of focal epilepsy screened positive for migraine. There were more women and less participants employed full time among the participants with comorbid migraine. They reported slightly more depressive and anxious symptoms than the participants without migraine. Migraine comorbidity was associated with ABNAS memory score (median: 2, range: 0-12, Mann Whitney U p-value: 0.015). However, migraine comorbidity was not associated with Cogstate scores nor ABNAS total scores or other ABNAS domain scores. In linear regressions, depression and anxiety scores were associated with the ABNAS memory score.

CONCLUSION

In this study, there was no association between migraine comorbidity and objective cognitive scores in patients with newly diagnosed focal epilepsy. The relationship between migraine comorbidity and subjective memory deficits seemed to be mediated by the higher prevalence of depression and anxiety symptoms in patients with epilepsy with comorbid migraine.

Is seizure frequency variance a predictable quantity?

Background

There is currently no formal method for predicting the range expected in an individual's seizure counts. Having access to such a prediction would be of benefit for developing more efficient clinical trials, but also for improving clinical care in the outpatient setting.

Methods

Using three independently collected patient diary datasets, we explored the predictability of seizure frequency. Three independent seizure diary databases were explored: SeizureTracker (n = 3016), Human Epilepsy Project (n = 93), and NeuroVista (n = 15). First, the relationship between mean and standard deviation in seizure frequency was assessed. Using that relationship, a prediction for the range of possible seizure frequencies was compared with a traditional prediction scheme commonly used in clinical trials. A validation dataset was obtained from a separate data export of SeizureTracker to further verify the predictions.

Results

A consistent mathematical relationship was observed across datasets. The logarithm of the average seizure count was linearly related to the logarithm of the standard deviation with a high correlation (R² > 0.83). The three datasets showed high predictive accuracy for this log-log relationship of 94%, compared with a predictive accuracy of 77% for a traditional prediction scheme. The independent validation set showed that the log-log predicted 94% of the correct ranges while the RR50 predicted 77%.

Conclusion

Reliably predicting seizure frequency variability is straightforward based on knowledge of mean seizure frequency, across several datasets. With further study, this may help to increase the power of RCTs, and guide clinical practice.

Does accounting for seizure frequency variability increase clinical trial power?

OBJECTIVE

Seizure frequency variability is associated with placebo responses in randomized controlled trials (RCT). Increased variability can result in drug misclassification and, hence, decreased statistical power. We investigated a new method that directly incorporated variability into RCT analysis, Z_V.

METHODS

Two models were assessed: the traditional 50%-responder rate (RR50), and the variability-corrected score, Z_V. Each predicted seizure frequency upper and lower limits using prior seizures. Accuracy was defined as percentage of time-intervals when the observed seizure frequencies were within the predicted limits. First, we tested the Z_V method on three datasets (SeizureTracker: n=3016, Human Epilepsy Project: n=107, and NeuroVista: n=15). An additional independent SeizureTracker validation dataset was used to generate a set of 200 simulated trials each for 5 different sample sizes (total N=100 to 500 by 100), assuming 20% dropout and 30% drug efficacy. "Power" was determined as the percentage of trials successfully distinguishing placebo from drug (p<0.05).

RESULTS

Prediction accuracy across datasets was, Z_V: 91-100%, RR50: 42-80%. Simulated RCT Z_V analysis achieved >90% power at N=100 per arm while RR50 required N=200 per arm.

SIGNIFICANCE

Z_V may increase the statistical power of an RCT relative to the traditional RR50.

Fluoroscopy-guided gastric peroral endoscopic pyloromyotomy (G-POEM): a more reliable and efficient method for treatment of refractory gastroparesis

INTRODUCTION

Prior studies show promising results of the gastric peroral endoscopic pyloromyotomy (G-POEM) procedure for treatment of refractory gastroparesis. One major technical challenge involved in this procedure is identifying the pyloric muscular ring (PMR). The aim of this study is to establish a reliable method for identification of the PMR during G-POEM.

METHODS

Fluoroscopy-guided G-POEM was performed by placing an endoclip at the 9 to 11'o clock position at the pylorus for identification of PMR. Conventional G-POEM was performed by observation of blue colored mucosa at the pylorus area as an indirect marker for PMR. The degree of the PMR identification was graded into well identified, identified, and not identified based on the appearance of the PMR. Procedure times were accurately documented. Gastroparesis cardinal symptoms index and gastric emptying scintigraphy were evaluated before and after the procedure.

RESULTS

Fourteen patients were studied, seven underwent fluoroscopy-guided G-POEM, and seven patients underwent conventional G-POEM. All procedures achieved technical success and no adverse events occurred. In the seven patients who underwent fluoroscopy-guided G-POEM, the PMR was well identified in four patients and identified in three patients. In the seven patients who underwent conventional G-POEM, the PMR was identified in four patients and not identified in three patients. The average time to complete the fluoroscopy-guided G-POEM was significantly shorter than that of the conventional G-POEM.

CONCLUSIONS

Fluoroscopy-guided G-POEM by placement of an endoclip at the pylorus was a reliable and safe method to direct the orientation of the submucosal tunnel, to facilitate the location of the PMR, and to shorten the procedure time.

Chronic migraine in women is associated with insulin resistance: a cross-sectional study

BACKGROUND AND PURPOSE

Migraine is a common neurological disorder. It can be divided into episodic migraine (EM) and chronic migraine (CM), based on headache frequency. Some studies have shown that insulin sensitivity is impaired in migraine; moreover, hypertension, diabetes and obesity are common in patients with CM. The aim of this study was to assess serum glucose, insulin levels and insulin resistance (IR) in a sample of episodic migraineurs, chronic migraineurs and non-pain healthy controls.

METHODS

Eighty-three women with EM, 83 with CM and 83 healthy controls were recruited. Headache was diagnosed according to the latest International Classification of Headache Disorders 2 criteria. Waist circumference, body mass index (BMI) and blood pressure were measured. Checked metabolic parameters included fasting glucose, the 2 h 75 g oral glucose tolerance test (2 h OGTT), serum HbA1c, blood lipid profile, C-reactive protein and prolactin. The homeostasis model assessment formula was used to calculate IR.

RESULTS

A significant prevalence of IR in CM was observed (P = 0.002). No significant associations were found with fasting glycaemia, the 2 h OGTT, HbA1c, blood lipid profile, C-reactive protein, prolactin and waist circumference. Obesity (BMI >30 kg/m(2)) was associated with an increased risk of CM [odds ratio (OR) 2.4]. When the outcome of interest was the association between IR and obesity, the OR was significantly increased compared with IR alone (OR = 13.2).

CONCLUSION

This may suggest that CM is associated with IR status, particularly when it is in partnership with obesity.

The epilepsy phenome/genome project

BACKGROUND

Epilepsy is a common neurological disorder that affects approximately 50 million people worldwide. Both risk of epilepsy and response to treatment partly depend on genetic factors, and gene identification is a promising approach to target new prediction, treatment, and prevention strategies. However, despite significant progress in the identification of genes causing epilepsy in families with a Mendelian inheritance pattern, there is relatively little known about the genetic factors responsible for common forms of epilepsy and so-called epileptic encephalopathies. Study design The Epilepsy Phenome/Genome Project (EPGP) is a multi-institutional, retrospective phenotype-genotype study designed to gather and analyze detailed phenotypic information and DNA samples on 5250 participants, including probands with specific forms of epilepsy and, in a subset, parents of probands who do not have epilepsy.

RESULTS

EPGP is being executed in four phases: study initiation, pilot, study expansion/establishment, and close-out. This article discusses a number of key challenges and solutions encountered during the first three phases of the project, including those related to (1) study initiation and management, (2) recruitment and phenotyping, and (3) data validation. The study has now enrolled 4223 participants.

CONCLUSIONS

EPGP has demonstrated the value of organizing a large network into cores with specific roles, managed by a strong Administrative Core that utilizes frequent communication and a collaborative model with tools such as study timelines and performance-payment models. The study also highlights the critical importance of an effective informatics system, highly structured recruitment methods, and expert data review.