Neurocritical care and neuromonitoring considerations in acute pediatric spinal cord injury.

Management of pediatric spinal cord injury (SCI) is an essential skill for all pediatric neurocritical care physicians. In this review, we focus on the evaluation and management of pediatric SCI, highlight a novel framework for the monitoring of such patients in the intensive care unit (ICU), and introduce advancements in critical care techniques in monitoring and management. The initial evaluation and characterization of SCI is crucial for improving outcomes as well as prognostication. While physical examination and imaging are the main stays of the work-up, we propose the use of somatosensory evoked potentials (SSEPs) and transcranial magnetic stimulation (TMS) for challenging clinical scenarios. SSEPs allow for functional evaluation of the dorsal columns consisting of tracts associated with hand function, ambulation, and bladder function. Meanwhile, TMS has the potential for informing prognostication as well as response to rehabilitation. Spine stabilization, and in some cases surgical decompression, along with respiratory and hemodynamic management are essential. Emerging research suggests that targeted spinal cerebral perfusion pressure may provide potential benefits. This review aims to increase the pediatric neurocritical care physician's comfort with SCI while providing a novel algorithm for monitoring spinal cord function in the ICU.

Multimodal neuromonitoring in the pediatric intensive care unit.

Neuromonitoring is used to assess the central nervous system in the intensive care unit. The purpose of neuromonitoring is to detect neurologic deterioration and intervene to prevent irreversible nervous system dysfunction. Neuromonitoring starts with the standard neurologic examination, which may lag behind the pathophysiologic changes. Additional modalities including continuous electroencephalography (CEEG), multiple physiologic parameters, and structural neuroimaging may detect changes earlier. Multimodal neuromonitoring now refers to an integrated combination and display of non-invasive and invasive modalities, permitting tailored treatment for the individual patient. This chapter reviews the non-invasive and invasive modalities used in pediatric neurocritical care.

Optimizing EEG monitoring in critically ill children at risk for electroencephalographic seizures.

OBJECTIVE: Strategies are needed to optimally deploy continuous EEG monitoring (CEEG) for electroencephalographic seizure (ES) identification and management due to resource limitations. We aimed to construct an efficient multi-stage prediction model guiding CEEG utilization to identify ES in critically ill children using clinical and EEG covariates. METHODS: The largest prospective single-center cohort of 1399 consecutive children undergoing CEEG was analyzed. A four-stage model was developed and trained to predict whether a subject required additional CEEG at the conclusion of each stage given their risk of ES. Logistic regression, elastic net, random forest, and CatBoost served as candidate methods for each stage and were evaluated using cross validation. An optimal multi-stage model consisting of the top-performing stage-specific models was constructed. RESULTS: When evaluated on a test set, the optimal multi-stage model achieved a cumulative specificity of 0.197 and cumulative F1 score of 0.326 while maintaining a high minimum cumulative sensitivity of 0.938. Overall, 11 % of test subjects with ES were removed from the model due to a predicted low risk of ES (falsely negative subjects). CEEG utilization would be reduced by 32 % and 47 % compared to performing 24 and 48 h of CEEG in all test subjects, respectively. We developed a web application called EEGLE (EEG Length Estimator) that enables straightforward implementation of the model. CONCLUSIONS: Application of the optimal multi-stage ES prediction model could either reduce CEEG utilization for patients at lower risk of ES or promote CEEG resource reallocation to patients at higher risk for ES.

Cognitive impairment in multiple sclerosis: Utility of electroencephalography.

OBJECTIVE: to evaluate associations between neurocognitive impairment and electroencephalography (EEG) data in Multiple Sclerosis (MS). METHODS: patients aged between 18 and 65 years, diagnosed with MS accordingly to the McDonald 2017 criteria and who were in remission for at least one month were included. Cognitive functions were evaluated by validated neuropsychological tests for Tunisian population. Electroencephalography data of each patient were analysed, Grand Total EEG (GTE) score was calculated and we evaluated their statistical links with cognitive impairment. RESULTS: Thirty five patients were included. Slower background activity was associated with presence of: reduced information processing speed (IPS) (p = 0,03), verbal memory impairment (p = 0,04) and executive dysfunction (p = 0,016). The score 3 of GTE (reactivity of background activity) was associated with reduced IPS (p = 0,007) and executive dysfunction (p = 0,014). We found a positive correlation between background activity and Tunisian Verbal Test (TVLT) (ρ =0,46 ; p = 0,005) and Symbol Digit Modalities Test (SDMT) (ρ =0,35 ; p = 0,03). Sensitivity of GTE score was 68,4% for executive dysfunction (cut-off=2,5) and 66,7% for reduced IPS (cut-off=2,5). CONCLUSIONS: Our results have shown utility of EEG in detecting cortical involvement and its correlation with cognitive impairment in MS patients. SIGNIFICANCE: EEG could be a tool for monitoring cortical involvement during MS and predict cognitive impairment.

k-Shape clustering for extracting macro-patterns in intracranial pressure signals.

BACKGROUND: Intracranial pressure (ICP) monitoring is a core component of neurosurgical diagnostics. With the introduction of telemetric monitoring devices in the last years, ICP monitoring has become feasible in a broader clinical setting including monitoring during full mobilization and at home, where a greater diversity of ICP waveforms are present. The need for identification of these variations, the so-called macro-patterns lasting seconds to minutes-emerges as a potential tool for better understanding the physiological underpinnings of patient symptoms. METHODS: We introduce a new methodology that serves as a foundation for future automatic macro-pattern identification in the ICP signal to comprehensively understand the appearance and distribution of these macro-patterns in the ICP signal and their clinical significance. Specifically, we describe an algorithm based on k-Shape clustering to build a standard library of such macro-patterns. RESULTS: In total, seven macro-patterns were extracted from the ICP signals. This macro-pattern library may be used as a basis for the classification of new ICP variation distributions based on clinical disease entities. CONCLUSIONS: We provide the starting point for future researchers to use a computational approach to characterize ICP recordings from a wide cohort of disorders.

Blood product resuscitation mitigates the effects of aeromedical evacuation after polytrauma.

BACKGROUND: The combined injury of traumatic brain injury and hemorrhagic shock has been shown to worsen coagulopathy and systemic inflammation, thereby increasing posttraumatic morbidity and mortality. Aeromedical evacuation to definitive care may exacerbate postinjury morbidity because of the inherent hypobaric hypoxic environment. We hypothesized that blood product resuscitation may mitigate the adverse physiologic effects of postinjury flight. METHODS: An established porcine model of controlled cortical injury was used to induce traumatic brain injury. Intracerebral monitors were placed to record intracranial pressure, brain tissue oxygenation, and cerebral perfusion. Each of the 42 pigs was hemorrhaged to a goal mean arterial pressure of 40 ± 5 mm Hg for 1 hour. Pigs were grouped according to resuscitation strategy used-Lactated Ringer's (LR) or shed whole blood (WB)-then placed in an altitude chamber for 2 hours at ground, 8,000 ft, or 22,000 ft, and then observed for 4 hours. Hourly blood samples were analyzed for proinflammatory cytokines and lactate. Internal jugular vein blood flow was monitored continuously for microbubble formation with altitude changes. RESULTS: Cerebral perfusion, tissue oxygenation, and intracranial pressure were unchanged among the six study groups. Venous microbubbles were not observed even with differing altitude or resuscitation strategy. Serum lactate levels from hour 2 of flight to the end of observation were significantly elevated in 22,000 + LR compared with 8,000 + LR and 22,000 + WB. Serum IL-6 levels were significantly elevated in 22,000 + LR compared with 22,000 + WB, 8,000 + LR and ground+LR at hour 1 of observation. Serum tumor necrosis factor-α was significantly elevated at hour 2 of flight in 8,000 + LR versus ground+LR, and in 22,000 + LR vs. 22,000 + WB at hour 1 of observation. Serum IL-1ß was significantly elevated hour 1 of flight between 8,000 + LR and ground+LR. CONCLUSION: Crystalloid resuscitation during aeromedical transport may cause a prolonged lactic acidosis and proinflammatory response that can predispose multiple-injury patients to secondary cellular injury. This physiologic insult may be prevented by using blood product resuscitation strategies.

Microdialysis and microperfusion electrodes in neurologic disease monitoring.

Contemporary biomarker collection techniques in blood and cerebrospinal fluid have to date offered only modest clinical insights into neurologic diseases such as epilepsy and glioma. Conversely, the collection of human electroencephalography (EEG) data has long been the standard of care in these patients, enabling individualized insights for therapy and revealing fundamental principles of human neurophysiology. Increasing interest exists in simultaneously measuring neurochemical biomarkers and electrophysiological data to enhance our understanding of human disease mechanisms. This review compares microdialysis, microperfusion, and implanted EEG probe architectures and performance parameters. Invasive consequences of probe implantation are also investigated along with the functional impact of biofouling. Finally, previously developed microdialysis electrodes and microperfusion electrodes are reviewed in preclinical and clinical settings. Critically, current and precedent microdialysis and microperfusion probes lack the ability to collect neurochemical data that is spatially and temporally coincident with EEG data derived from depth electrodes. This ultimately limits diagnostic and therapeutic progress in epilepsy and glioma research. However, this gap also provides a unique opportunity to create a dual-sensing technology that will provide unprecedented insights into the pathogenic mechanisms of human neurologic disease.

Intracranial Pressure Monitoring in Poor-Grade Patients with Aneurysmal Subarachnoid Hemorrhage Treated by Coiling.

OBJECTIVE: The main objective of the present study was to analyze the intracranial pressure (ICP) and cerebral perfusion pressure (CPP) changes during coiling. We also evaluated the prevalence of rebleeding and outcomes for patients monitored before and after coiling. METHODS: Ninety-nine consecutive poor-grade patients with aneurysmal subarachnoid hemorrhage (aSAH; World Federation of Neurological Surgeons grade IV and V) were enrolled in our prospective observational study. For 31 patients, ICP and CPP monitoring was started immediately after the diagnosis of aSAH, and the values were recorded every 15 minutes during coiling (early ICP group). For 68 patients, ICP and CPP monitoring began after coiling (late ICP group). The outcomes were evaluated at 90 days using the modified Rankin scale. RESULTS: At the beginning of coiling, the ICP was >20 mm Hg in 10 patients (35.7%). The median ICP was 18 mm Hg (range, 5-60 mm Hg). The CPP was <60 mm Hg in 6 patients (24%). The median CPP was 70 mm Hg (range, 30-101 mm Hg). Despite medical treatment and/or cerebrospinal fluid drainage, 51.6% of the patients monitored during coiling had at least one episode of intracranial hypertension (defined as ICP >20 mm Hg), and 51.6% had at least one episode of reduced CPP (defined as CPP <60 mm Hg). Early monitoring (before aneurysm repair) was not associated with rebleeding. At 90 days, the functional recovery was better in the early ICP group (P = 0.004). CONCLUSIONS: During coiling, patients with poor-grade aSAH can experience episodes of intracranial hypertension and reduced CPP. Early and appropriate treatment of elevated ICP was not associated with rebleeding and might have improved the outcomes.

Invasive Multimodal Neuromonitoring in Aneurysmal Subarachnoid Hemorrhage: A Systematic Review.

Background and Purpose: Aneurysmal subarachnoid hemorrhage is a devastating disease leaving surviving patients often severely disabled. Delayed cerebral ischemia (DCI) has been identified as one of the main contributors to poor clinical outcome after subarachnoid hemorrhage. The objective of this review is to summarize existing clinical evidence assessing the diagnostic value of invasive neuromonitoring (INM) in detecting DCI and provide an update of evidence since the 2014 consensus statement on multimodality monitoring in neurocritical care. Methods: Three invasive monitoring techniques were targeted in the data collection process: brain tissue oxygen tension (ptiO2), cerebral microdialysis, and electrocorticography. Prospective and retrospective studies as well as case series (≥10 patients) were included as long as monitoring was used to detect DCI or guide DCI treatment. Results: Forty-seven studies reporting INM in the context of DCI were included (ptiO2: N=21; cerebral microdialysis: N=22; electrocorticography: N=4). Changes in brain oxygen tension are associated with angiographic vasospasm or reduction in regional cerebral blood flow. Metabolic monitoring with trend analysis of the lactate to pyruvate ratio using cerebral microdialysis, identifies patients at risk for DCI. Clusters of cortical spreading depolarizations are associated with clinical neurological worsening and cerebral infarction in selected patients receiving electrocorticography monitoring. Conclusions: Data supports the use of INM for the detection of DCI in selected patients. Generalizability to all subarachnoid hemorrhage patients is limited by design bias of available studies and lack of randomized trials. Continuous data recording with trend analysis and the combination of INM modalities can provide tailored treatment support in patients at high risk for DCI. Future trials should test interventions triggered by INM in relation to cerebral infarctions.

Long-term monitoring of chronic demyelination and remyelination in a rat ischemic stroke model using macromolecular proton fraction mapping.

Remyelination is a key process enabling post-stroke brain tissue recovery and plasticity. This study aimed to explore the feasibility of demyelination and remyelination monitoring in experimental stroke from the acute to chronic stage using an emerging myelin imaging biomarker, macromolecular proton fraction (MPF). After stroke induction by transient middle cerebral artery occlusion, rats underwent repeated MRI examinations during 85 days after surgery with histological endpoints for the animal subgroups on the 7th, 21st, 56th, and 85th days. MPF maps revealed two sub-regions within the infarct characterized by distinct temporal profiles exhibiting either a persistent decrease by 30%-40% or a transient decrease followed by return to nearly normal values after one month of observation. Myelin histology confirmed that these sub-regions had nearly similar extent of demyelination in the sub-acute phase and then demonstrated either chronic demyelination or remyelination. The remyelination zones also exhibited active axonal regrowth, reconstitution of compact fiber bundles, and proliferation of neuronal and oligodendroglial precursors. The demyelination zones showed more extensive astrogliosis from the 21st day endpoint. Both sub-regions had substantially depleted neuronal population over all endpoints. These results histologically validate MPF mapping as a novel approach for quantitative assessment of myelin damage and repair in ischemic stroke.

Satisfaction with and reliability of in-hospital video-EEG monitoring systems in epilepsy diagnosis - A German multicenter experience.

OBJECTIVE: To analyze satisfaction with and reliability of video-electroencephalography-monitoring systems (VEMS) in epilepsy diagnostics. METHODS: A survey was conducted between December 2020 and January 2021 among German epilepsy centers using well-established customer satisfaction (CS) and quality assurance metrics. RESULTS: Among 16 participating centers, CS with VEMS was low, with only 13% of customers actively recommending their system. Only 50% of users were satisfied with the overall performance of their VEMS, and a low 18% were satisfied with the manufacturer's customer service. User interface, software stability, lack of regular updates, and missing customer-oriented improvements were reported as frequent problems jeopardizing diagnosis in approximately every 10th patient. The greatest potential for improvement was identified for software and hardware stability as well as customer service. CONCLUSION: Satisfaction with VEMS and their customer service was low, and diagnostics were regularly affected by software or hardware errors. Even if this can be partly explained by the technical complexity of VEMS, there is an urgent need for improvements with regard to the reliability and durability of system components as well as signal synchrony and data management. SIGNIFICANCE: This analysis highlights low consumer satisfaction of users with VEMS and uncovers frequent problems and potential for improvement.

Seizure Control in Neonates Undergoing Screening vs Confirmatory EEG Monitoring.

OBJECTIVE: To determine whether screening continuous EEG monitoring (cEEG) is associated with greater odds of treatment success for neonatal seizures. METHODS: We included term neonates with acute symptomatic seizures enrolled in the Neonatal Seizure Registry (NSR), a prospective, multicenter cohort of neonates with seizures. We compared 2 cEEG approaches: (1) screening cEEG, initiated for indications of encephalopathy or paralysis without suspected clinical seizures; and (2) confirmatory cEEG, initiated for the indication of clinical events suspicious for seizures, either alone or in addition to other indications. The primary outcome was successful response to initial seizure treatment, defined as seizures resolved without recurrence within 30 minutes after initial loading dose of antiseizure medicine. Multivariable logistic regression analyses assessed the association between cEEG approach and successful seizure treatment. RESULTS: Among 514 neonates included, 161 (31%) had screening cEEG and 353 (69%) had confirmatory cEEG. Neonates with screening cEEG had a higher proportion of successful initial seizure treatment than neonates with confirmatory cEEG (39% vs 18%; p < 0.0001). After adjusting for covariates, there remained a greater odds ratio (OR) for successful initial seizure treatment in the screening vs confirmatory cEEG groups (adjusted OR 2.44, 95% confidence interval 1.45-4.11, p = 0.0008). CONCLUSIONS: These findings provide evidence from a large, contemporary cohort of neonates that a screening cEEG approach may improve odds of successful treatment of acute seizures. CLASSIFICATION OF EVIDENCE: This study provides Class III evidence that for neonates a screening cEEG approach, compared to a confirmatory EEG approach, increases the probability of successful treatment of acute seizures.

Long-term wireless streaming of neural recordings for circuit discovery and adaptive stimulation in individuals with Parkinson's disease.

Neural recordings using invasive devices in humans can elucidate the circuits underlying brain disorders, but have so far been limited to short recordings from externalized brain leads in a hospital setting or from implanted sensing devices that provide only intermittent, brief streaming of time series data. Here, we report the use of an implantable two-way neural interface for wireless, multichannel streaming of field potentials in five individuals with Parkinson's disease (PD) for up to 15 months after implantation. Bilateral four-channel motor cortex and basal ganglia field potentials streamed at home for over 2,600 h were paired with behavioral data from wearable monitors for the neural decoding of states of inadequate or excessive movement. We validated individual-specific neurophysiological biomarkers during normal daily activities and used those patterns for adaptive deep brain stimulation (DBS). This technological approach may be widely applicable to brain disorders treatable by invasive neuromodulation.

Neuromonitoring After Cardiac Arrest: Can Twenty-First Century Medicine Personalize Post Cardiac Arrest Care?

Cardiac arrest survivors comprise a heterogeneous population, in which the etiology of arrest, systemic and neurologic comorbidities, and sequelae of post-cardiac arrest syndrome influence the severity of secondary brain injury. The degree of secondary neurologic injury can be modifiable and is influenced by factors that alter cerebral physiology. Neuromonitoring techniques provide tools for evaluating the evolution of physiologic variables over time. This article reviews the pathophysiology of hypoxic-ischemic brain injury, provides an overview of the neuromonitoring tools available to identify risk profiles for secondary brain injury, and highlights the importance of an individualized approach to post cardiac arrest care.

Blunt and Penetrating Severe Traumatic Brain Injury.

Severe traumatic brain injury is a common problem. Current practices focus on the importance of early resuscitation, transfer to high-volume centers, and provider expertise across multiple specialties. In the emergency department, patients should receive urgent intracranial imaging and consideration for tranexamic acid. Close observation in the intensive care unit environment helps identify problems, such as seizure, intracranial pressure crisis, and injury progression. In addition to traditional neurologic examination, patients benefit from use of intracranial monitors. Monitors gather physiologic data on intracranial and cerebral perfusion pressures to help guide therapy. Brain tissue oxygenation monitoring and cerebromicrodialysis show promise in studies.

Changes in electroencephalographic power and bicoherence spectra according to depth of dexmedetomidine sedation in patients undergoing spinal anesthesia.

Background: Assessment the depth of dexmedetomidine sedation using electroencephalographic (EEG) features can improve the quality of procedural sedation. Previous volunteer studies of dexmedetomidine-induced EEG changes need to be validated, and changes in bicoherence spectra during dexmedetomidine sedation has not been revealed yet. We aimed to investigate the dexmedetomidine-induced EEG change using power spectral and bicoherence analyses in the clinical setting. Patients and Methods: Thirty-six patients undergoing orthopedic surgery under spinal anesthesia were enrolled in this study. Dexmedetomidine sedation was conducted by the stepwise increase in target effect site concentration (Ce) while assessing sedation levels. Bispectral index (BIS) and frontal electroencephalography were recorded continuously, and the performance of BIS and changes in power and bicoherence spectra were analyzed with the data from the F3 electrode. Results: The prediction probability values for detecting different sedation levels were 0.847, 0.841, and 0.844 in BIS, 95% spectral edge frequency, and dexmedetomidine Ce, respectively. As the depth of sedation increased, δ power increased, but high ß and γ power decreased significantly (P <0.001). α and spindle power increased significantly under light and moderate sedation (P <0.001 in light vs baseline and deep sedation; P = 0.002 and P <0.001 in moderate sedation vs baseline and deep sedation, respectively). The bicoherence peaks of the δ and α-spindle regions along the diagonal line of the bicoherence matrix emerged during moderate and deep sedation. Peak bicoherence in the δ area showed sedation-dependent increases (29.93%±7.38%, 36.72%±9.70%, 44.88%±12.90%; light, moderate, and deep sedation; P = 0.008 and P <0.001 in light sedation vs moderate and deep sedation, respectively; P = 0.007 in moderate sedation vs deep sedation), whereas peak bicoherence in the α-spindle area did not change (22.92%±4.90%, 24.72%±4.96%, and 26.96%±8.42%, respectively; P=0.053). Conclusions: The increase of δ power and the decrease of high-frequency power were associated with the gradual deepening of dexmedetomidine sedation. The δ bicoherence peak increased with increasing sedation level and can serve as an indicator reflecting dexmedetomidine sedation levels.

Neural Responses to Heartbeats Detect Residual Signs of Consciousness during Resting State in Postcomatose Patients.

The neural monitoring of visceral inputs might play a role in first-person perspective (i.e., the unified viewpoint of subjective experience). In healthy participants, how the brain responds to heartbeats, measured as the heartbeat-evoked response (HER), correlates with perceptual, bodily, and self-consciousness. Here we show that HERs in resting-state EEG data distinguishes between postcomatose male and female human patients (n = 68, split into training and validation samples) with the unresponsive wakefulness syndrome and in patients in a minimally conscious state with high accuracy (random forest classifier, 87% accuracy, 96% sensitivity, and 50% specificity in the validation sample). Random EEG segments not locked to heartbeats were useful to predict unconsciousness/consciousness, but HERs were more accurate, indicating that HERs provide specific information on consciousness. HERs also led to more accurate classification than heart rate variability. HER-based consciousness scores correlate with glucose metabolism in the default-mode network node located in the right superior temporal sulcus, as well as with the right ventral occipitotemporal cortex. These results were obtained when consciousness was inferred from brain glucose met`abolism measured with positron emission topography. HERs reflected the consciousness diagnosis based on brain metabolism better than the consciousness diagnosis based on behavior (Coma Recovery Scale-Revised, 77% validation accuracy). HERs thus seem to capture a capacity for consciousness that does not necessarily translate into intentional overt behavior. These results confirm the role of HERs in consciousness, offer new leads for future bedside testing, and highlight the importance of defining consciousness and its neural mechanisms independently from behavior.

Automated seizure detection using wearable devices: A clinical practice guideline of the International League Against Epilepsy and the International Federation of Clinical Neurophysiology.

The objective of this clinical practice guideline (CPG) is to provide recommendations for healthcare personnel working with patients with epilepsy, on the use of wearable devices for automated seizure detection in patients with epilepsy, in outpatient, ambulatory settings. The Working Group of the International League Against Epilepsy and the International Federation of Clinical Neurophysiology developed the CPG according to the methodology proposed by the ILAE Epilepsy Guidelines Working Group. We reviewed the published evidence using The Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) statement and evaluated the evidence and formulated the recommendations following the Grading of Recommendations Assessment, Development and Evaluation (GRADE) system. We found high level of evidence for the accuracy of automated detection of generalized tonic-clonic seizures (GTCS) and focal-to-bilateral tonic-clonic seizures (FBTCS) and recommend use of wearable automated seizure detection devices for selected patients when accurate detection of GTCS and FBTCS is recommended as a clinical adjunct. We also found moderate level of evidence for seizure types without GTCs or FBTCs. However, it was uncertain whether the detected alarms resulted in meaningful clinical outcomes for the patients. We recommend using clinically validated devices for automated detection of GTCS and FBTCS, especially in unsupervised patients, where alarms can result in rapid intervention (weak/conditional recommendation). At present, we do not recommend clinical use of the currently available devices for other seizure types (weak/conditional recommendation). Further research and development are needed to improve the performance of automated seizure detection and to document their accuracy and clinical utility.

Prolonged epileptic discharges predict seizure recurrence in JME: Insights from prolonged ambulatory EEG.

OBJECTIVE: Markers of seizure recurrence are needed to personalize antiseizure medication (ASM) therapy. In the clinical practice, EEG features are considered to be related to the risk of seizure recurrence for genetic generalized epilepsies (GGE). However, to our knowledge, there are no studies analyzing systematically specific EEG features as indices of ASM efficacy in GGE. In this study, we aimed at identifying EEG indicators of ASM responsiveness in Juvenile Myoclonic Epilepsy (JME), which, among GGE, is characterized by specific electroclinical features. METHODS: We compared the features of prolonged ambulatory EEG (paEEG, 22 h of recording) of JME patients experiencing seizure recurrence within a year ("cases") after EEG recording, with those of patients with sustained seizure freedom for at least 1 year after EEG ("controls"). We included only EEG recordings of patients who had maintained the same ASM regimen (dosage and type) throughout the whole time period from the EEG recording up to the outcome events (which was seizure recurrence for the "cases", or 1-year seizure freedom for "controls"). As predictors, we evaluated the total number, frequency, mean and maximum duration of epileptiform discharges (EDs) and spike density (i.e. total EDs duration/artifact-free EEG duration) recorded during the paEEG. The same indexes were assessed also in standard EEG (stEEG), including activation methods. RESULTS: Both the maximum length and the mean duration of EDs recorded during paEEG significantly differed between cases and controls; when combined in a binary logistic regression model, the maximum length of EDs emerged as the only valid predictor. A cut-off of EDs duration of 2.68 seconds discriminated between cases and controls with a 100% specificity and a 93% sensitivity. The same indexes collected during stEEG lacked both specificity and sensitivity. SIGNIFICANCE: The occurrence of prolonged EDs in EEG recording might represent an indicator of antiepileptic drug failure in JME patients.