Unravelling the origin of the reward positivity: a human intracranial event-related brain potential study.

The reward positivity (RewP) is an event-related brain potential (ERP) component that emerges approximately 250 to 350 milliseconds (ms) after receiving reward-related feedback stimuli and is believed to be important for reinforcement learning and reward processing. Although numerous localization studies have indicated that the anterior cingulate cortex (ACC) is the neural generator of this component, other studies have identified sources outside of the ACC, fuelling a debate about its origin. Because the results of EEG and MEG source localization studies are severely limited by the inverse problem, we addressed this question by leveraging the high spatial and temporal resolution of intracranial EEG. We predicted that we would identify a neural generator of the RewP in the caudal ACC. We recorded intracranial EEG in 19 refractory epilepsy patients who underwent invasive video-EEG monitoring at Ghent University Hospital, Belgium. Participants engaged in the virtual T-maze task (vTMT), a trial-and-error task known to elicit a canonical RewP, while scalp and intracranial EEG were simultaneously recorded. The RewP was identified using a difference wave approach for both scalp and intracranial EEG. The data were aggregated across participants to create a virtual "meta-participant" that contained all the recorded intracranial ERPs (iERPs) with respect to their intracranial contact locations. We used both a hypothesis-driven (focused on ACC) and exploratory (whole-brain analysis) approach to segment the brain into regions of interest (ROI). For each ROI, we evaluated the degree to which the time course of the absolute current density (ACD) activity mirrored the time course of the RewP, and confirmed the statistical significance of the results using permutation analysis. The grand average waveform of the scalp data revealed a RewP at 309 ms after reward feedback with a frontocentral scalp distribution, consistent with the identification of this component as the RewP. The meta-participant contained iERPs recorded from 582 intracranial contacts in total. The ACD activity of the aggregated iERPs were most similar to the RewP in left caudal ACC, left dorsolateral prefrontal cortex, left frontomedial cortex, and left white matter, with the highest score attributed to caudal ACC, as predicted. To our knowledge, this is the first study that uses intracranial EEG aggregated across multiple human epilepsy patients and current source density analysis to identify the neural generator(s) of the RewP. These results provide direct evidence that the ACC is a neural generator of the RewP.

Very high epilepsy prevalence in rural Southern Rwanda: The underestimated burden of epilepsy in sub-Saharan Africa.

OBJECTIVES: Up to 85% of people living with epilepsy (PwE) reside in low-and middle-income countries. In sub-Saharan Africa, the lifetime prevalence of epilepsy is 16 per 1000 persons. In Northern rural Rwanda, a 47.7 per 1000 prevalence has been reported. As variations in prevalence across geographical areas have been observed, we studied the prevalence in Southern rural Rwanda using the same robust methodology as applied in the North. METHODS: We conducted a three-stage, cross-sectional, door-to-door survey in two rural villages in Southern Rwanda from June 2022 to April 2023. First, trained enumerators administered the validated Limoges questionnaire for epilepsy screening. Second, neurologists examined the persons who had screened positively to confirm the epilepsy diagnosis. Third, cases with an inconclusive assessment were separately reexamined by two neurologists to reevaluate the diagnosis. RESULTS: Enumerators screened 1745 persons (54.4% female, mean age: 24 ± 19.3 years), of whom 304 (17.4%) screened positive. Epilepsy diagnosis was confirmed in 133 (52.6% female, mean age: 30 ± 18.2 years) and active epilepsy in 130 persons. Lifetime epilepsy prevalence was 76.2 per 1000 (95% CI: 64.2-89.7‰). The highest age-specific rate occurred in the 29-49 age group. No gender-specific differences were noted. In 22.6% of the PwE, only non-convulsive seizures occurred. The treatment gap was 92.2%, including a diagnosis gap of 79.4%. CONCLUSION: We demonstrated a very high epilepsy prevalence in Southern rural Rwanda, with over 20% of cases having only non-convulsive seizures, which are often underdiagnosed in rural Africa. In line with previous Rwandan reports, we reiterate the high burden of the disease in the country. Geographic variation in prevalence throughout Africa may result from differences in risk and aetiological factors. Case-control studies are underway to understand such differences and propose adapted health policies for epilepsy prevention.

Long-term evaluation of anterior thalamic deep brain stimulation for epilepsy in the European MORE registry.

OBJECTIVE: Short-term outcomes of deep brain stimulation of the anterior nucleus of the thalamus (ANT-DBS) were reported for people with drug-resistant focal epilepsy (PwE). Because long-term data are still scarce, the Medtronic Registry for Epilepsy (MORE) evaluated clinical routine application of ANT-DBS. METHODS: In this multicenter registry, PwE with ANT-DBS were followed up for safety, efficacy, and battery longevity. Follow-up ended after 5 years or upon study closure. Clinical characteristics and stimulation settings were compared between PwE with no benefit, improvers, and responders, that is, PwE with average monthly seizure frequency reduction rates of ≥50%. RESULTS: Of 170 eligible PwE, 104, 62, and 49 completed the 3-, 4-, and 5-year follow-up, respectively. Most discontinuations (68%) were due to planned study closure as follow-up beyond 2 years was optional. The 5-year follow-up cohort had a median seizure frequency reduction from 16 per month at baseline to 7.9 per month at 5-year follow-up (p < .001), with most-pronounced effects on focal-to-bilateral tonic-clonic seizures (n = 15, 77% reduction, p = .008). At last follow-up (median 3.5 years), 41% (69/170) of PwE were responders. Unifocal epilepsy (p = .035) and a negative history of epilepsy surgery (p = .002) were associated with larger average monthly seizure frequency reductions. Stimulation settings did not differ between response groups. In 179 implanted PwE, DBS-related adverse events (AEs, n = 225) and serious AEs (n = 75) included deterioration in epilepsy or seizure frequency/severity/type (33; 14 serious), memory/cognitive impairment (29; 3 serious), and depression (13; 4 serious). Five deaths occurred (none were ANT-DBS related). Most AEs (76.3%) manifested within the first 2 years after implantation. Activa PC depletion (n = 37) occurred on average after 45 months. SIGNIFICANCE: MORE provides further evidence for the long-term application of ANT-DBS in clinical routine practice. Although clinical benefits increased over time, side effects occurred mainly during the first 2 years. Identified outcome modifiers can help inform PwE selection and management.

The 2022 European postgraduate (residency) programme in neurology in a historical and international perspective.

BACKGROUND AND PURPOSE: Neurology residency programmes, which were first established at the beginning of the 20th century, have become mandatory all over Europe in the last 40-50 years. The first European Training Requirements in Neurology (ETRN) were published in 2005 and first updated in 2016. This paper reports the most recent revisions of the ETRN. METHODS: Members of the EAN board performed an in depth revision of the ETNR 2016-version, which was reviewed by members of the European Board and Section of Neurology of the UEMS, the Education and Scientific Panels, the Resident and Research Fellow Section and the Board of the EAN, as well as the presidents of the 47 European National Societies. RESULTS: The new (2022) ETRN suggest a 5-year training subdivided in three phases: a first phase (2 years) of general neurology training, a second phase (2 years) of training in neurophysiology/neurological subspecialties and a third phase (1 year) to expand clinical training (e.g., in other neurodisciplines) or for research (path for clinical neuroscientist). The necessary theoretical and clinical competences as well as learning objectives in diagnostic tests have been updated, are newly organized in four levels and include 19 neurological subspecialties. Finally, the new ETRN require, in addition to a programme director, a team of clinician-educators who regularly review the resident's progress. The 2022 update of the ETRN reflects emerging requirements for the practice of neurology and contributes to the international standardization of training necessary for the increasing needs of residents and specialists across Europe.

Challenges to epilepsy management in Rwandan women living with epilepsy.

BACKGROUND AND PURPOSE: In Rwanda, epilepsy prevalence ranges between 29‰ and 49‰. Many women living with epilepsy (WwE) are of childbearing age. Epilepsy characteristics and management, contraception, pregnancy, puerperium and stigma in WwE presenting at the neurology clinic of Ndera, Rwanda, were investigated. METHODS: This prospective cross-sectional study investigated demographics, epilepsy characteristics, treatment, contraception, folic acid use, pregnancy, puerperium and stigma in WwE aged ≥18 years. Subgroups were analysed by status of any pregnancy and time of epilepsy diagnosis relative to pregnancy, with significant differences expected. RESULTS: During December 2020 and January 2021, a hundred WwE were enrolled (range 18-67 years). Fifty-two women had never been pregnant, 39 women had epilepsy onset before pregnancy and nine were diagnosed after pregnancy. No significant differences in age, marital status or occupation were observed. Contraception was used by 27%, of whom 50% were taking enzyme-inducing anti-epileptic medication. Valproate was used by 46% of WwE of reproductive age. Thirty-nine women with epilepsy onset before pregnancy reported 91 pregnancies, with 14% spontaneous abortions. None used folic acid before conception, and 59% only during pregnancy. Five of 78 newborns were preterm. No offspring had major congenital malformations. Nearly 25% of WwE were not compliant with their anti-epileptic medication schedule during pregnancy or breastfeeding. Internalized stigma was observed in more than 60%. Up to 25% had been discriminated against at school or work. CONCLUSION: A comprehensive strategy considering the reproductive health and societal challenges of WwE is needed to drive optimal epilepsy management, reproductive health outcomes and societal inclusion.

A strategic neurological research agenda for Europe: Towards clinically relevant and patient-centred neurological research priorities.

BACKGROUND AND PURPOSE: Neurological disorders constitute a significant portion of the global disease burden, affecting >30% of the world's population. This prevalence poses a substantial threat to global health in the foreseeable future. A lack of awareness regarding this high burden of neurological diseases has led to their underrecognition, underappreciation, and insufficient funding. Establishing a strategic and comprehensive research agenda for brain-related studies is a crucial step towards aligning research objectives among all pertinent stakeholders and fostering greater societal awareness. METHODS: A scoping literature review was undertaken by a working group from the European Academy of Neurology (EAN) to identify any existing research agendas relevant to neurology. Additionally, a specialized survey was conducted among all EAN scientific panels, including neurologists and patients, inquiring about their perspectives on the current research priorities and gaps in neurology. RESULTS: The review revealed the absence of a unified, overarching brain research agenda. Existing research agendas predominantly focus on specialized topics within neurology, resulting in an imbalance in the number of agendas across subspecialties. The survey indicated a prioritization of neurological disorders and research gaps. CONCLUSIONS: Building upon the findings from the review and survey, key components for a strategic and comprehensive neurological research agenda in Europe were delineated. This research agenda serves as a valuable prioritization tool for neuroscientific researchers, as well as for clinicians, donors, and funding agencies in the field of neurology. It offers essential guidance for creating a roadmap for research and clinical advancement, ultimately leading to heightened awareness and reduced burden of neurological disorders.

General neurology: Current challenges and future implications.

BACKGROUND AND PURPOSE: In the coming decades, the world will face an increasing burden of neurological disorders (ND) and an urgent need to promote brain health. These challenges contrast with an insufficient neurological workforce in most countries, as well as decreasing numbers of general neurologists and neurologists attracted to work in general neurology (GN). This white paper aims to review the current situation of GN and reflect on its future. METHODS: The European Academy of Neurology (EAN) task force (TF) met nine times between November 2021 and June 2023. During the 2023 EAN annual meeting, attendees were asked to answer five questions concerning the future of GN. The document was sent for suggestions and eventually approval to the board and the presidents of the 47 national societies of the EAN. RESULTS: The TF first identified four relevant current and future challenges related to GN: (i) definition, (ii) practice, (iii) education, and (iv) research. The TF then identified seven initiatives to further develop GN at both the academic and community level. Finally, the TF formulated 16 recommendations to promote GN in the future. CONCLUSIONS: GN will remain essential in the coming decades to provide rapid, accessible, and comprehensive management of patients with ND that is affordable and cost-effective. There is also a need for research, education, and other initiatives aiming to facilitate improved working conditions, recognition, and prestige for those pursuing a career in GN.

Neurostimulation for childhood epilepsy.

The experience with neurostimulation for childhood epilepsy is far less extensive than for adults. Nevertheless, the implementation of these techniques could be of great value, especially considering the detrimental effects of ongoing seizures on the developing brain. In this review, we discuss the available evidence for neurostimulation for childhood epilepsy. Vagus nerve stimulation (VNS) is the most studied neurostimulation modality in children. Based on mostly retrospective, open-label studies, we can conclude that VNS has a similar safety and efficacy profile in children compared to adults. Although there is little available evidence for deep brain stimulation (DBS) and responsive neurostimulation (RNS) in children, both DBS and RNS show promise in reducing seizure frequency with few complications. The implementation of non-invasive techniques with a more appealing safety profile has gained interest. Small randomized control trials and open-label studies have investigated transcranial direct current simulation for childhood epilepsy, demonstrating promising but inconsistent findings.

Investigating the Working Mechanism of Transcranial Direct Current Stimulation.

BACKGROUND: Transcranial direct current stimulation (tDCS) is used to modulate neuronal activity, but the exact mechanism of action (MOA) is unclear. This study investigates tDCS-induced modulation of the corticospinal excitability and the underlying MOA. By anesthetizing the scalp before applying tDCS and by stimulating the cheeks, we investigated whether stimulation of peripheral and/or cranial nerves contributes to the effects of tDCS on corticospinal excitability. MATERIALS AND METHODS: In a randomized cross-over study, four experimental conditions with anodal direct current stimulation were compared in 19 healthy volunteers: 1) tDCS over the motor cortex (tDCS-MI), 2) tDCS over the motor cortex with a locally applied topical anesthetic (TA) on the scalp (tDCS-MI + TA), 3) DCS over the cheek region (DCS-C), and 4) sham tDCS over the motor cortex(sham). tDCS was applied for 20 minutes at 1 mA. Motor evoked potentials (MEPs) were measured before tDCS and immediately, 15, 30, 45, and 60 minutes after tDCS. A questionnaire was used to assess the tolerability of tDCS. RESULTS: A significant MEP amplitude increase compared with baseline was found 30 minutes after tDCS-MI, an effect still observed 60 minutes later; no time∗condition interaction effect was detected. In the other three conditions (tDCS-MI + TA, DCS-C, sham), no significant MEP modulation was found. The questionnaire indicated that side effects are significantly lower when the local anesthetic was applied before stimulation than in the other three conditions. CONCLUSIONS: The significant MEP amplitude increase observed from 30 minutes on after tDCS-MI supports the modulatory effect of tDCS on corticospinal neurotransmission. This effect lasted one hour after stimulation. The absence of a significant modulation when a local anesthetic was applied suggests that effects of tDCS are not solely established through direct cortical stimulation but that stimulation of peripheral and/or cranial nerves also might contribute to tDCS-induced modulation.

Exploration of Theta Burst-Induced Modulation of Transcranial Magnetic Stimulation-Evoked Potentials Over the Motor Cortex.

OBJECTIVES: This study investigates the way theta burst stimulation (TBS) applied to the motor cortex (M1) affects TMS-evoked potentials (TEPs). There have been few direct comparisons of continuous TBS (cTBS) and intermittent TBS (iTBS), and there is a lack of consensus from existing literature on the induced effects. We performed an exploratory trial to assess the effect of M1-cTBS and M1-iTBS on TEP components. MATERIALS AND METHODS: In a cross-over design, 15 participants each completed three experimental sessions with ≥one week in between sessions. The effect of a single TBS train administered over M1 was investigated using TEPs recorded at the same location, 20 to 30 minutes before and in the first 10 minutes after the intervention. In each session, a different type of TBS (cTBS, iTBS, or active control cTBS) was administered in a single-blinded randomized order. For six different TEP components (N15, P30, N45, P60, N100, and P180), amplitude was compared before and after the intervention using cluster-based permutation (CBP) analysis. RESULTS: We were unable to identify a significant modulation of any of the six predefined M1 TEP components after a single train of TBS. When waiving statistical correction for multiple testing in view of the exploratory nature of the study, the CBP analysis supports a reduction of the P180 amplitude after iTBS (p = 0.015), whereas no effect was observed after cTBS or in the active control condition. The reduction occurred in ten of 15 subjects, showing intersubject variability. CONCLUSIONS: The observed decrease in the P180 amplitude after iTBS may suggest a neuromodulatory effect of iTBS. Despite methodologic issues related to our study and the potential sensory contamination within this latency range of the TEP, we believe that our finding deserves further investigation in hypothesis-driven trials of adequate power and proper design, focusing on disentanglement between TEPs and peripherally evoked potentials, in addition to indicating reproducibility across sessions and subjects. CLINICAL TRIAL REGISTRATION: The Clinicaltrials.gov registration number for the study is NCT05206162.

Increased Dentate Gyrus Excitability in the Intrahippocampal Kainic Acid Mouse Model for Temporal Lobe Epilepsy.

The intrahippocampal kainic acid (IHKA) mouse model is an extensively used in vivo model to investigate the pathophysiology of mesial temporal lobe epilepsy (mTLE) and to develop novel therapies for drug-resistant epilepsy. It is characterized by profound hippocampal sclerosis and spontaneously occurring seizures with a major role for the injected damaged hippocampus, but little is known about the excitability of specific subregions. The purpose of this study was to electrophysiologically characterize the excitability of hippocampal subregions in the chronic phase of the induced epilepsy in the IHKA mouse model. We recorded field postsynaptic potentials (fPSPs) after electrical stimulation in the CA1 region and in the dentate gyrus (DG) of hippocampal slices of IHKA and healthy mice using a multielectrode array (MEA). In the DG, a significantly steeper fPSP slope was found, reflecting higher synaptic strength. Population spikes were more prevalent with a larger spatial distribution in the IHKA group, reflecting a higher degree of granule cell output. Only minor differences were found in the CA1 region. These results point to increased neuronal excitability in the DG but not in the CA1 region of the hippocampus of IHKA mice. This method, in which the excitability of hippocampal slices from IHKA mice is investigated using a MEA, can now be further explored as a potential new model to screen for new interventions that can restore DG function and potentially lead to novel therapies for mTLE.

Hippocampal seizures differentially modulate locus coeruleus activity and result in consistent time-locked release of noradrenaline in rat hippocampus.

The locus coeruleus (LC) is a small brainstem nucleus and is the sole source of noradrenaline in the neocortex, hippocampus and cerebellum. Noradrenaline is a powerful neuromodulator involved in the regulation of excitability and plasticity of large-scale brain networks. In this study, we performed a detailed assessment of the activity of locus coeruleus neurons and changes in noradrenergic transmission during acute hippocampal seizures evoked with perforant path stimulation, using state-of-the-art methodology. Action potentials of LC neurons, of which some were identified by means of optogenetics, were recorded in anesthetized rats using a multichannel high-density electrophysiology probe. The seizure-induced change in firing rate differed between LC neurons: 55% of neurons decreased in firing rate during seizures, while 28% increased their firing rate. Topographic analysis of multi-unit activity over the electrophysiology probe showed a topographic clustering of neurons that were inhibited or excited during seizures. Changes in hippocampal noradrenaline transmission during seizures were assessed using a fluorescent biosensor for noradrenaline, GRABNE2m, in combination with fiber photometry, in both anesthetized and awake rats. Although our neuronal recordings indicated both inhibition and excitation of LC neurons during seizures, a consistent release of noradrenaline was observed. Concentrations of noradrenaline increased at seizure onset and decreased during or shortly after the seizure. In conclusion, this study showed consistent but heterogeneous modulation of LC neurons and a consistent time-locked release of hippocampal noradrenaline during acute hippocampal seizures.

Decreasing incidence of stroke, ischaemic heart disease and dementia in Norway, 1990-2019, a Global Burden of Disease study: an opportunity.

BACKGROUND AND PURPOSE: The declining incidence of stroke, ischaemic heart disease (IHD) and dementia (the 'triple threat') in Norway encourages further investigation. The risks and trends of the three conditions were analysed using data from the Global Burden of Disease study. METHODS: Global Burden of Disease 2019 estimations were used for age-, sex- and risk-factor-specific incidence and prevalence of the 'triple threat', their risk-factor-attributed deaths and disability combined, their age-standardized rates per 100,000 population in 2019 and their changes during 1990-2019. Data are presented as means and 95% uncertainty intervals. RESULTS: In 2019, 71.1 thousand Norwegians were living with dementia, 157.2 thousand with IHD and 95.2 thousand with stroke. In 2019, there were 9.9 thousand (8.5 to 11.3) new cases of dementia (35.0% increase since 1990), 17.0 thousand (14.6 to 19.6) with IHD (3.6% decrease) and 8.0 thousand (7.0 to 9.1) with stroke (12.9% decrease) in Norway. During 1990-2019, their age-standardized incidence rates decreased significantly-dementia by -5.4% (-8.4% to -3.2%), IHD by -30.0% (-31.4% to -28.6%) and stroke by -35.3% (-38.3% to -32.2%). There were significant declines in the attributable risks to both environmental and behavioural factors in Norway, but contradictory trends for metabolic risk factors during 1990-2019. CONCLUSIONS: The risk of the 'triple threat' conditions is declining in Norway, despite the increased prevalence. This offers the opportunity to find out why and how and to accelerate their joint prevention through new approaches and the promotion of the National Brain Health Strategy.

Association of depression and epilepsy in Rwanda: A prospective longitudinal study.

INTRODUCTION: Depression is the most common psychiatric comorbidity for persons living with epilepsy. In Rwanda, the prevalence of epilepsy and depression are high, with 4,9% and 13.0% respectively. This prospective interventional study aimed to determine the prevalence and incidence of depression and the outcome of persons living with epilepsy (PwE) with depression attending the outpatient neurology department of a tertiary center. METHODS: Persons living with epilepsy enrolled between February and June 2018 in a screening cohort with a 12-month follow-up. At every 3-month study visit, PwE were screened for depression using the Patient Health Questionnaire (PHQ-9) questionnaire. Any positively screened subject was administered the Hamilton Depression Rating Scale (HDRS) to confirm the diagnosis and severity of depression. Subjects with moderate to severe depression (MSD), were started on treatment and were followed for another year. We describe the prevalence and incidence of depression, baseline characteristics, epilepsy and depression outcomes, and changes in PGI-C. RESULTS: Of 572 PwE enrolled, 46 were diagnosed with MSD in a twelve-month period, resulting in an incidence of MSD of 32.7/1000 patient-years. The prevalence of any depression and MSD was 14.2% and 4.7%, respectively. Longer epilepsy duration and seizure status at baseline were associated with MSD. Significant improvements in PGI-C and seizure frequency were observed after treatment optimization. CONCLUSION: The use of PHQ-9 and HDRS proved successful in identifying depression in PwE. Combined treatment of epilepsy and depression resulted in improved outcomes, warranting the implementation of depression screening every six months in daily neurology practice.

The European Academy of Neurology Brain Health Strategy: One brain, one life, one approach.

BACKGROUND AND PURPOSE: Brain health is essential for health, well-being, productivity and creativity across the entire life. Its definition goes beyond the absence of disease embracing all cognitive, emotional, behavioural and social functions which are necessary to cope with life situations. METHODS: The European Academy of Neurology (EAN) Brain Health Strategy responds to the high and increasing burden of neurological disorders. It aims to develop a non-disease-, non-age-centred holistic and positive approach ('one brain, one life, one approach') to prevent neurological disorders (e.g., Alzheimer's disease and other dementias, stroke, epilepsy, headache/migraine, Parkinson's disease, multiple sclerosis, sleep disorders, brain cancer) but also to preserve brain health and promote recovery after brain damage. RESULTS: The pillars of the EAN Brain Health Strategy are (1) to contribute to a global and international brain health approach (together with national and subspecialty societies, other medical societies, the World Health Organization, the World Federation of Neurology, patients' organizations, industry and other stakeholders); (2) to support the 47 European national neurological societies, healthcare and policymakers in the implementation of integrated and people-centred campaigns; (3) to foster research (e.g., on prevention of neurological disorders, determinants and assessments of brain health); (4) to promote education of students, neurologists, general practitioners, other medical specialists and health professionals, patients, caregivers and the general public; (5) to raise public awareness of neurological disorders and brain health. CONCLUSIONS: By adopting this 'one brain, one life, one approach' strategy in cooperation with partner societies, international organizations and policymakers, a significant number of neurological disorders may be prevented whilst the overall well-being of individuals is enhanced by maintaining brain health through the life course.

Effectiveness of community health workers on identification and mobilization of persons living with epilepsy in rural Rwanda using a validated screening tool.

INTRODUCTION: Engagement and training of community health workers (CHWs) have demonstrated their value in different conditions. Despite repeat epilepsy trainings of CHWs in Northern Rwanda, the treatment gap remained high. We hypothesized that effectiveness of CHWs on mobilization of patients living with epilepsy (PwE) could be improved using a validated tool for epilepsy screening. METHODS: CHWs associated with health centers (HCs) of Gataraga, Kimonyi and Karwasa attended a 1-day training on epilepsy and Limoges epilepsy screening questionnaire (Kinyarwanda version). Thereafter, CHWs screened households in their villages for persons with one or more positive answer. CHWs then accompanied positively screened persons to a consultation for clinical evaluation and diagnosis by neurologists, and demographic data were collected. CHW variables were collected retrospectively. RESULTS: A total of 1308 persons were screened positive by 281 CHWs. Clinical diagnosis of epilepsy was confirmed in 589 and in 93 additional unscreened PwE, presenting voluntarily at the consultation. Pre-intervention number of 48 PwE increased to 682 after, a 14.2-fold increase. The overall treatment gap amounted to 93.0%. The age distribution of male PwE preponderance at younger age inverted to females at older age. CHW characteristics showed non-significant differences within and across HCs. Logistic regression did not relate CHW age, gender, and experience to screening results. DISCUSSION: Equipping CHWs with a validated screening tool was effective in identifying and mobilizing PwE in a short time frame and offers opportunity for future scaling. Nonetheless, barriers to sustainability of care will need to be addressed before.

mBrain: towards the continuous follow-up and headache classification of primary headache disorder patients.

BACKGROUND: The diagnosis of headache disorders relies on the correct classification of individual headache attacks. Currently, this is mainly done by clinicians in a clinical setting, which is dependent on subjective self-reported input from patients. Existing classification apps also rely on self-reported information and lack validation. Therefore, the exploratory mBrain study investigates moving to continuous, semi-autonomous and objective follow-up and classification based on both self-reported and objective physiological and contextual data. METHODS: The data collection set-up of the observational, longitudinal mBrain study involved physiological data from the Empatica E4 wearable, data-driven machine learning (ML) algorithms detecting activity, stress and sleep events from the wearables' data modalities, and a custom-made application to interact with these events and keep a diary of contextual and headache-specific data. A knowledge-based classification system for individual headache attacks was designed, focusing on migraine, cluster headache (CH) and tension-type headache (TTH) attacks, by using the classification criteria of ICHD-3. To show how headache and physiological data can be linked, a basic knowledge-based system for headache trigger detection is presented. RESULTS: In two waves, 14 migraine and 4 CH patients participated (mean duration 22.3 days). 133 headache attacks were registered (98 by migraine, 35 by CH patients). Strictly applying ICHD-3 criteria leads to 8/98 migraine without aura and 0/35 CH classifications. Adapted versions yield 28/98 migraine without aura and 17/35 CH classifications, with 12/18 participants having mostly diagnosis classifications when episodic TTH classifications (57/98 and 32/35) are ignored. CONCLUSIONS: Strictly applying the ICHD-3 criteria on individual attacks does not yield good classification results. Adapted versions yield better results, with the mostly classified phenotype (migraine without aura vs. CH) matching the diagnosis for 12/18 patients. The absolute number of migraine without aura and CH classifications is, however, rather low. Example cases can be identified where activity and stress events explain patient-reported headache triggers. Continuous improvement of the data collection protocol, ML algorithms, and headache classification criteria (including the investigation of integrating physiological data), will further improve future headache follow-up, classification and trigger detection. Trial registration This trial was retrospectively registered with number NCT04949204 on 24 June 2021 at www. CLINICALTRIALS: gov .

Investigating the Effect of Transcutaneous Auricular Vagus Nerve Stimulation on Cortical Excitability in Healthy Males.

OBJECTIVES: As a potential treatment for epilepsy, transcutaneous auricular vagus nerve stimulation (taVNS) has yielded inconsistent results. Combining transcranial magnetic stimulation with electromyography (TMS-EMG) and electroencephalography (TMS-EEG) can be used to investigate the effect of interventions on cortical excitability by evaluating changes in motor evoked potentials (MEPs) and TMS-evoked potentials (TEPs). The goal of this study is to objectively evaluate the effect of taVNS on cortical excitability with TMS-EMG and TMS-EEG. These findings are expected to provide insight in the mechanism of action and help identify more optimal stimulation paradigms. MATERIALS AND METHODS: In this prospective single-blind cross-over study, 15 healthy male subjects underwent active and sham taVNS for 60 min, using a maximum tolerated stimulation current. Single and paired pulse TMS was delivered over the right-sided motor hotspot to evaluate MEPs and TEPs before and after the intervention. MEP statistical analysis was conducted with a two-way repeated measures ANOVA. TEPs were analyzed with a cluster-based permutation analysis. Linear regression analysis was implemented to investigate an association with stimulation current. RESULTS: MEP and TEP measurements were not affected by taVNS in this study. An association was found between taVNS stimulation current and MEP outcome measures indicating a decrease in cortical excitability in participants who tolerated higher taVNS currents. A subanalysis of participants (n = 8) who tolerated a taVNS current ≥2.5 mA showed a significant increase in the resting motor threshold, decrease in MEP amplitude and modulation of the P60 and P180 TEP components. CONCLUSIONS: taVNS did not affect cortical excitability measurements in the overall population in this study. However, taVNS has the potential to modulate specific markers of cortical excitability in participants who tolerate higher stimulation levels. These findings indicate the need for adequate stimulation protocols based on the recording of objective outcome parameters.

Laryngeal Muscle-Evoked Potential Recording as an Indicator of Vagal Nerve Fiber Activation.

BACKGROUND: Vagus nerve stimulation (VNS) is an adjunctive therapy for drug-resistant epilepsy. Noninvasive evoked potential recordings in laryngeal muscles (LMEPs) innervated by vagal branches may provide a marker to assess effective vagal nerve fiber activation. We investigated VNS-induced LMEPs in patients with epilepsy in acute and chronic settings. MATERIALS AND METHODS: A total of 17 of 25 patients underwent LMEP recordings at initiation of therapy (acute group); 15 of 25 patients after one year of VNS (chronic group); and 7 of 25 patients were tested at both time points (acute + chronic group). VNS-induced LMEPs were recorded following different pulse widths and output currents using six surface laryngeal EMG electrodes to calculate input/output curves and estimate LMEP latency, threshold current for minimal (Ithreshold), half-maximal (I50), and 95% of maximal (I95) response induction and amplitude of maximal response (Vmax). These were compared with the acute + chronic group and between responders and nonresponders in the acute and chronic group. RESULTS: VNS-induced LMEPs were present in all patients. Ithreshold and I95 values ranged from 0.25 to 1.00 mA and from 0.42 to 1.77 mA, respectively. Estimated mean LMEP latencies were 10 ± 0.1 milliseconds. No significant differences between responders and nonresponders were observed. In the acute + chronic group, Ithreshold values remained stable over time. However, at the individual level in this group, Vmax was lower in all patients after one year compared with baseline. CONCLUSIONS: Noninvasive VNS-induced LMEP recording is feasible both at initiation of VNS therapy and after one year. Low output currents (0.25-1.00 mA) may be sufficient to activate vagal Aα-motor fibers. Maximal LMEP amplitudes seemed to decrease after chronic VNS therapy in patients.

Ex Vivo Feedback Control of Neurotransmission Using a Photocaged Adenosine A1 Receptor Agonist.

We report the design, synthesis, and validation of the novel compound photocaged N6-cyclopentyladenosine (cCPA) to achieve precisely localized and timed release of the parent adenosine A1 receptor agonist CPA using 405 nm light. Gi protein-coupled A1 receptors (A1Rs) modulate neurotransmission via pre- and post-synaptic routes. The dynamics of the CPA-mediated effect on neurotransmission, characterized by fast activation and slow recovery, make it possible to implement a closed-loop control paradigm. The strength of neurotransmission is monitored as the amplitude of stimulus-evoked local field potentials. It is used for feedback control of light to release CPA. This system makes it possible to regulate neurotransmission to a pre-defined level in acute hippocampal brain slices incubated with 3 µM cCPA. This novel approach of closed-loop photopharmacology holds therapeutic potential for fine-tuned control of neurotransmission in diseases associated with neuronal hyperexcitability.