EEG Assessment in Patients With Disorders of Consciousness: Aims, Advantages, Limits, and Pitfalls.

This study presents a brief review of literature exploring simple EEG-polygraphic examinations and procedures that can be carried out at a patient's bedside. These include EEG with a common electrode array and sleep evaluation. The review briefly discusses more complex analytical techniques, such as the application of advanced EEG signal processing methods developed by our research group, to define what type of consistent markers are suitable for clinical use or to better understand complex patient conditions. These advanced analytical techniques aim to detect relevant EEG-based markers that could be useful in evaluating patients and predicting outcomes. These data could contribute to future developments in research.

The COVID-19 outbreak and approaches to performing EEG in Europe.

The coronavirus SARS-CoV-2 disease (COVID-19) pandemic affects availability and performance of neurophysiological diagnostic methods, including EEG. Our objective was to outline the current situation regarding EEG-based investigations across Europe. A web-based survey was distributed to centres within the European Reference Network on rare and complex epilepsies (ERN EpiCARE). Responses were collected between April 9 and May 15, 2020. Results were analysed with Microsoft Excel, Python Pandas and SciPy. Representants from 47 EpiCARE centres from 22 countries completed the survey. At the time of completing the survey, inpatient video-EEGs had been stopped or restricted in most centres (61.7% vs. 36.2% for adults, and 38.3% vs. 53.2% for children). Invasive investigations and epilepsy surgery were similarly affected. Acute EEGs continued to be performed, while indications for outpatient EEGs were limited and COVID-19 triage put in place. The strictness of measures varied according to extent of the outbreak in a given country. The results indicate a profound impact of COVID-19 on neurophysiological diagnostics, especially inpatient video-EEGs, invasive investigations, and epilepsy surgery. The COVID-19 pandemic may hamper care for patients in need of EEG-based investigations, particularly patients with seizure disorders. ERN EpiCARE will work on recommendations on how to rapidly adapt to such situations in order to alleviate consequences for our patients.

Comprehensive educational plan for patients with epilepsy and comorbidity (EDU-COM): a pragmatic randomised trial.

BACKGROUND: The impact of educational strategies in the management of adverse treatment effects and drug interactions in adult patients with epilepsy with comorbidities remains undetermined. OBJECTIVE: The EDU-COM study is a randomised, pragmatic trial investigating the effect of a patient-tailored educational plan in patients with epilepsy with comorbidity. METHODS: 174 adult patients with epilepsy with chronic comorbidities, multiple-drug therapy and reporting at least one adverse treatment effect and/or drug interaction at study entry were randomly assigned to the educational plan or usual care. The primary endpoint was the number of patients becoming free from adverse treatment events and/or drug interactions after a 6-month follow-up. The number of adverse treatment events and drug interactions, health-related quality of life (HRQOL) summary score changes and the monetary costs of medical contacts and drugs were assessed as secondary outcomes. RESULTS: The primary endpoint was met by 44.0% of patients receiving the educational plan versus 28.9% of those on usual care (p=0.0399). The control group reported a significantly higher risk not to meet successfully the primary endpoint at the end of the study: OR (95% CI) of 2.29 (1.03 to 5.09). A separate analysis on drug adverse effects and drug interactions showed that the latter were more sensitive to the effect of educational treatment. Quality of life and costs were not significantly different in the two groups. CONCLUSIONS: A patient-tailored educational strategy is effective in reducing drug-related problems (particularly drug interactions) in epilepsy patients with chronic comorbidities, without adding significant monetary costs. Registered at ClinicalTrials.gov, identifier NCT01804322, (http://www.clinicaltrials.gov).

Focal epilepsies in adult patients attending two epilepsy centers: classification of drug-resistance, assessment of risk factors, and usefulness of "new" antiepileptic drugs.

PURPOSE: To classify the grade of antiepileptic drug (AED) resistance in a cohort of patients with focal epilepsies, to recognize the risk factors for AED resistance, and to estimate the helpfulness of "new-generation" AEDs. METHODS: We included 1,155 adults with focal epilepsies who were observed consecutively after 1990 and followed regularly at two epilepsy centers. We systematically collected the clinical, diagnostic, and therapeutic data using a custom-written database. We classified the patients as seizure-free or AED resistant according to the International League Against Epilepsy (ILAE) criteria, and we evaluated the risk factors associated with AED resistance using logistic regression analysis. We further grouped AED-resistant patients in different grades (I, II, and III) according to the number of AEDs already tried as proposed by Perucca. KEY FINDINGS: AED resistance occurred in 57.8% of the 729 patients with symptomatic focal epilepsies and was positively associated with electroencephalography (EEG) abnormalities, seizure type, and the presence of mesial temporal sclerosis. Among 426 patients without detectable causes, the percentage of AED resistance was significantly lower (39.2%) and correlated with EEG abnormalities and psychiatric symptoms. Among AED-resistant patients, the majority (64.6%) had tried three or more AEDs, which fit the more severe grade III proposed by Perucca. Among seizure-free patients, more than one-half (57%) needed to try two or more AEDs before reaching seizure control (14.9% needed three or more AEDs). Furthermore, among seizure-free patients who could be previously classified as resistant to two or more AEDs, 52.2% reached seizure freedom while receiving treatment with "new generation" AEDs. SIGNIFICANCE: The ILAE classification of AED resistance, as well the graded classification proposed by Perucca, was easily exploitable in our patients, although these classifications systems appear to have a limited value in predicting seizure outcome. Actually, a small but not negligible percentage of patients reached seizure freedom after trying several AEDs (including "new" AEDs), suggesting repeated trials may be necessary for seizure control.

Neural signatures of economic parameters during decision-making: a functional MRI (FMRI), electroencephalography (EEG) and autonomic monitoring study.

Adaptive behaviour requires an ability to obtain rewards by choosing between different risky options. Financial gambles can be used to study effective decision-making experimentally, and to distinguish processes involved in choice option evaluation from outcome feedback and other contextual factors. Here, we used a paradigm where participants evaluated 'mixed' gambles, each presenting a potential gain and a potential loss and an associated variable outcome probability. We recorded neural responses using autonomic monitoring, electroencephalography (EEG) and functional neuroimaging (fMRI), and used a univariate, parametric design to test for correlations with the eleven economic parameters that varied across gambles, including expected value (EV) and amount magnitude. Consistent with behavioural economic theory, participants were risk-averse. Gamble evaluation generated detectable autonomic responses, but only weak correlations with outcome uncertainty were found, suggesting that peripheral autonomic feedback does not play a major role in this task. Long-latency stimulus-evoked EEG potentials were sensitive to expected gain and expected value, while alpha-band power reflected expected loss and amount magnitude, suggesting parallel representations of distinct economic qualities in cortical activation and central arousal. Neural correlates of expected value representation were localized using fMRI to ventromedial prefrontal cortex, while the processing of other economic parameters was associated with distinct patterns across lateral prefrontal, cingulate, insula and occipital cortices including default-mode network and early visual areas. These multimodal data provide complementary evidence for distributed substrates of choice evaluation across multiple, predominantly cortical, brain systems wherein distinct regions are preferentially attuned to specific economic features. Our findings extend biologically-plausible models of risky decision-making while providing potential biomarkers of economic representations that can be applied to the study of deficits in motivational behaviour in neurological and psychiatric patients.

Myoclonus in Creutzfeldt-Jakob disease: polygraphic and video-electroencephalography assessment of 109 patients.

We used electroencephalography (EEG)-polygraphic recordings to classify myoclonus in 109 patients with Creutzfeldt-Jakob disease (CJD) on the basis of its electromyography (EMG) pattern, time course, distribution, and EEG correlates. We recorded myoclonic jerks in 55 patients (50.4%), and we classified them as periodic myoclonus in 28, rhythmic in 13, and irregular in 20 (6 patients showed two types of myoclonus). Myoclonus occurred as a prominently negative event (interrupting the EMG discharge) in 10. Periodic sharp-wave complexes (PSWCs) were present in all but one patient with myoclonic jerks but were time-locked with EMG-bursts only in case of periodic myoclonus. Jerk-locked back averaging revealed a variable EEG-EMG transfer-time commonly exceeding that characterizing cortical myoclonus. Myoclonus was frequently associated with Met/Met polymorphism at codon 129 of the prion protein gene, but it was also observed in association with Met/Val or Val/Val polymorphisms provided that the EEG showed the presence of the PSWC pattern. The presence of enlarged somatosensory evoked potentials significantly correlated with the myoclonic presentation, as did MR signal hyperintensity involving the cortical mantle. Our observations on the basis of standard polygraphic criteria suggest that CJD associates with a remarkable variety of myoclonic jerks, and therefore different brain structures are probably involved as generators. The significant association between the presence of all myoclonus types with PSWCs suggests that hyperexcitable corticosubcortical loops are always required to generate (or allow) both myoclonus and the EEG complexes, either they are time locked or not.