Quantitative EEG Research Articles

Methods for Identifying Epilepsy Surgery Targets Using Invasive EEG: A Systematic Review

Background: The pre-surgical evaluation for drug-resistant epilepsy achieves seizure freedom in only 50–60% of patients. Efforts to identify quantitative intracranial EEG (qEEG) biomarkers of epileptogenicity are needed. This review summarizes and evaluates the design of qEEG studies, discusses barriers to biomarker adoption, and proposes refinements of qEEG study protocols. Methods: We included exploratory and prediction prognostic studies from MEDLINE and Scopus published between 2017 and 2023 that investigated qEEG markers for identifying the epileptogenic network as the surgical target. Cohort parameters, ground truth references, and analytical approaches were extracted. Results: Out of 1789 search results, 128 studies were included. The study designs were highly heterogeneous. Half of the studies included a non-consecutive cohort, with sample sizes ranging from 2 to 166 patients (median of 16). The most common minimum follow-up was one year, and the seizure onset zone was the most common ground truth. Prediction studies were heterogeneous in their analytical approaches, and only 25 studies validated the marker through post-surgical outcome prediction. Outcome prediction performance decreased in larger cohorts. Conversely, longer follow-up periods correlated with higher prediction accuracy, and connectivity-based approaches yielded better predictions. The data and code were available in only 9% of studies. Conclusions: To enhance the validation qEEG markers, we propose standardizing study designs to resemble clinical trials. This includes using a consecutive cohort with long-term follow-up, validating against surgical resection as ground truth, and evaluating markers through post-surgical outcome prediction. These considerations would improve the reliability and clinical adoption of qEEG markers.

Abstract 4140169: Neonatal Electroencephalogram Alpha:Delta changes precede neurologic injury during Antegrade Cerebral Perfusion and Deep Hypothermic Circulatory Arrest

Background: Although neurologic injury commonly occurs following neonatal aortic arch reconstruction, the mechanism(s) are poorly understood. A decrease or inter-hemispheric difference in the electroencephalogram (EEG) Alpha:Delta ratio (A:D) precedes cerebral ischemia during antegrade cerebral perfusion (ACP). However, it is unknown if A:D changes precede neurologic injury during deep hypothermic circulatory arrest (DHCA). We hypothesized during DHCA, the A:D would decrease and that a significant A:D inter-hemispheric difference would precede neurologic injury. Methods: Neonates requiring aortic arch reconstruction underwent simultaneous quantitative EEG monitoring. Left vs. right hemispheric, anterior, and posterior A:Ds were recorded at baseline, arterial cannulation, cooling, ACP vs. DHCA, and the rewarming phases of the operation. Left vs. right A:D differences > 25% were considered significant for ischemia and the cumulative duration of a significant A:D inter-hemispheric difference was calculated. Post-operative neurologic injury was defined as either stroke or seizure. Results: From 86 neonates, 16.2 % (14) required DHCA and 83.8 % (72) ACP. There were no significant differences in the pre-operative demographics or baseline A:Ds between groups. Although the A:Ds remained similar during ACP, after 15 minutes the hemispheric A:Ds decreased significantly during DHCA (Figure 1). Eleven neonates (ACP-7 vs. DHCA-4) developed neurologic injury. The duration of an anterior A:D inter-hemispheric difference > 25% was significantly greater within neonates that developed neurologic injury (25 {IQR:0,65 minutes} vs. 5 {IQR: 0, 15 minutes}; p<0.001). Multivariate analysis demonstrated that the duration of an anterior A:D difference > 25% was independently associated with neurologic injury using either ACP or DHCA (Odds Ratio:1.081, 95% CI: 1.025, 1.141; p-value=0.004). Conclusion: Unlike ACP, the A:D decreased significantly during DHCA. During either DHCA or ACP, a significant anterior inter-hemispheric A:D difference was independently associated with neurologic injury and suggests the importance of quantifying the A:D during neonatal arch reconstruction.

EEG Infrastructure Within the Veterans Administration: A Survey.

EEG is a vital tool in the diagnosis and management of neurologic conditions prevalent among veterans such as seizures, epilepsy, and brain injuries. This cross-sectional study aimed to assess the state of EEG infrastructure within the Veterans Administration (VA), focusing on availability, utilization, and the potential avenues to addressing gaps in infrastructure. This survey was distributed to 123 VA hospitals using the Research Electronic Data Capture (REDCap) platform, gathering data on EEG equipment, staffing, and service provision from June to December 2023. Of the 123 VA hospitals surveyed, 70 responded (56.9% response rate). Most respondents (88.6%) reported having EEG services, although only 38.7% offering continuous EEG (cEEG). Respondents reported having less EEG technologists, machines, and faculty readers than what they thought would be ideal. Significant correlations were found between the availability of resources (e.g., number of EEG machines) and service capabilities, including remote access and cEEG. The use of alternative EEG technologies such as rapid or quantitative EEG varied greatly. Interest in participating in the VA Tele-EEG program was reported by 59.4% of respondents. There is large variability in EEG infrastructure across the VA. Tele-EEG has the potential to maintain continuity of operations through challenges affecting staffing and to improve EEG service access, especially in resource-limited settings. Expanding access to quantitative, rapid, and tele-EEG services may enhance patient management and may be a potential avenue to explore as the VA continues to invest in and grow its capacity for treating neurologic conditions.

Quantitative EEG and its relationship with attentional control in patients with anxiety disorders

IntroductionAttentional control is crucial in the development and maintenance of anxiety disorders. Understanding the underlying mechanisms of attentional control can help to shed light on the neuropathological processes in anxiety disorders (ANX). Quantitative electroencephalography (QEEG) offers a cost-effective, noninvasive method for examining the neuropathological mechanisms of mental disorders.MethodsIn this study, 67 patients with ANX and 45 healthy controls (HC) were recruited. EEG recordings were obtained for 5 minutes in an eyes-closed condition. QEEG was employed to evaluate the mechanisms of attentional control in ANX.ResultsNeurophysiological measures indicated that anxiety patients exhibited a more frontal topographic pattern of theta/beta ratio (TBR) compared to HC. Additionally, a significant decrease in temporal beta power was observed in the ANX group. Correlation analysis revealed that decreased beta power and increased TBR were significant association between attentional control deficits in ANX.DiscussionThese findings provide electrophysiological evidence of impaired attentional control processing in anxiety patients, characterized by decreased temporal beta power and increased frontal TBR. Temporal beta power and frontal TBR may serve as promising biomarkers for attentional control in ANX.

Unique quantitative electroencephalography differences and related behavioral dynamics in Crohn’s disease

Crohn's disease (CD) is a major type of inflammatory bowel disease (IBD) characterized by idiopathic, chronic inflammation with a patchy transmural inflammatory pattern. CD patients experience a decreased quality of life due to symptoms such as diarrhea, abdominal pain, anemia and fever. This study had a cross-sectional single-center design. The experimental group was composed of patients diagnosed with CD according to the Chinese consensus on diagnosis and treatment in inflammatory bowel disease (2018, Beijing). Fifty CD patients and 41 healthy controls were involved in this study and underwent quantitative electroencephalography (QEEG). Analysis showed that the LZC of QEEG in electrode positions O1, O2 and P4 was lower in the CD group than in the control group. Significant differences in EEG LZC were found at electrode positions F4 and P3 when comparing CD patients with a disease duration of over 10 years to those with a duration of less than 10 years. In CD, the connections between the occipital region and other brain regions may be reduced, and the dynamic behaviors may be simplified. With greater durations of CD, patients may gradually develop simplification of behavioral dynamics in particular brain regions.

DELirium treatment with Transcranial Electrical Stimulation (DELTES): study protocol for a multicentre, randomised, double-blind, sham-controlled trial.

Delirium, a clinical manifestation of acute encephalopathy, is associated with extended hospitalisation, long-term cognitive dysfunction, increased mortality and high healthcare costs. Despite intensive research, there is still no targeted treatment. Delirium is characterised by electroencephalography (EEG) slowing, increased relative delta power and decreased functional connectivity. Recent studies suggest that transcranial alternating current stimulation (tACS) can entrain EEG activity, strengthen connectivity and improve cognitive functioning. Hence, tACS offers a potential treatment for augmenting EEG activity and reducing the duration of delirium. This study aims to evaluate the feasibility and assess the efficacy of tACS in reducing relative delta power. A randomised, double-blind, sham-controlled trial will be conducted across three medical centres in the Netherlands. The study comprises two phases: a pilot phase (n=30) and a main study phase (n=129). Participants are patients aged 50 years and older who are diagnosed with delirium using the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition, Text Revision criteria (DSM-5-TR), that persists despite treatment of underlying causes. During the pilot phase, participants will be randomised (1:1) to receive either standardised (10 Hz) tACS or sham tACS. In the main study phase, participants will be randomised to standardised tACS, sham tACS or personalised tACS, in which tACS settings are tailored to the participant. All participants will undergo daily 30 min of (sham) stimulation for up to 14 days or until delirium resolution or hospital discharge. Sixty-four-channel resting-state EEG will be recorded pre- and post the first tACS session, and following the final tACS session. Daily delirium assessments will be acquired using the Intensive Care Delirium Screening Checklist and Delirium Observation Screening Scale. The pilot phase will assess the percentage of completed tACS sessions and increased care requirements post-tACS. The primary outcome variable is change in relative delta EEG power. Secondary outcomes include (1) delirium duration and severity, (2) quantitative EEG measurements, (3) length of hospital stay, (4) cognitive functioning at 3 months post-tACS and (5) tACS treatment burden. Study recruitment started in April 2024 and is ongoing. The study has been approved by the Medical Ethics Committee of the Utrecht University Medical Center and the Institutional Review Boards of all participating centres. Trial results will be disseminated via peer-reviewed publications and conference presentations. NCT06285721.

Meta-analysis on QEEG Changes to Antidepressant Treatment Among Patients with Depression

Introduction: Diagnostic and treatment accuracy of depression can lead to a better and possibly earlier response and remission in patients. The literature, though scanty, seems to suggest that quantitative electroencephalography (QEEG) can predict the outcome of antidepressant effects. Methodology: Articles published between January 1990 and July 2019, including those dealing with QEEG recordings before and after the initiation of antidepressant medication, were included. The pooled effect size and subgroup analysis of waveforms were calculated to predict response to antidepressants. Result: In all, 572 results were retrieved from the searches, of which 20 studies were included. Pooled data using a random-effects model (REM) calculated an effect size of 0.80 (95% CI [0.64–0.97]). Heterogeneity of the sample was low with Tau² = 0.02; df = 18 ( P = .30); I² = 12%. Moreover, subgroup analysis showed that theta band frequencies were better at predicting response than alpha band frequencies (the standard mean difference [SMD] for theta was 0.91 compared to 0.68 for alpha waves). Conclusions: QEEG is a valuable predictor of the antidepressant response. Among the EEG frequencies, the theta band showed the most significant change with treatment.

A Phase 1 Assessment of the Safety, Tolerability, Pharmacokinetics and Pharmacodynamics of (2R,6R)-Hydroxynorketamine in Healthy Volunteers.

(R,S)-Ketamine (ketamine) is a dissociative anesthetic that also possesses analgesic and antidepressant activity. Undesirable dissociative side effects and misuse potential limit expanded use of ketamine in several mental health disorders despite promising clinical activity and intensifying medical need. (2R,6R)-Hydroxynorketamine (RR-HNK) is a metabolite of ketamine that lacks anesthetic and dissociative activity but maintains antidepressant and analgesic activity in multiple preclinical models. To enable future assessments in selected human indications, we report the safety, tolerability, pharmacokinetics (PK), and pharmacodynamics (PD) of RR-HNK in a Phase 1 study in healthy volunteers (NCT04711005). A six-level single-ascending dose (SAD) (0.1-4 mg/kg) and a two-level multiple ascending dose (MAD) (1 and 2 mg/kg) study was performed using a 40-minute IV administration emulating the common practice for ketamine administration for depression. Safety assessments showed RR-HNK possessed a minimal adverse event profile and no serious adverse events at all doses examined. Evaluations of dissociation and sedation demonstrated that RR-HNK did not possess anesthetic or dissociative characteristics in the doses examined. RR-HNK PK parameters were measured in both the SAD and MAD studies and exhibited dose-proportional increases in exposure. Quantitative electroencephalography (EEG) measurements collected as a PD parameter based on preclinical findings and ketamine's established effect on gamma-power oscillations demonstrated increases of gamma power in some participants at the lower/mid-range doses examined. Cerebrospinal fluid examination confirmed RR-HNK exposure within the central nervous system (CNS). Collectively, these data demonstrate RR-HNK is well tolerated with an acceptable PK profile and promising PD outcomes to support the progression into Phase 2.

Quantitative EEG biomarkers for STXBP1-related disorders.

EEG patterns and quantitative EEG (qEEG) features have been poorly explored in monogenic epilepsies. Herein, we investigate regional differences in EEG frequency composition in patients with STXBP1 developmental and epileptic encephalopathy (STXBP1-DEE). We conducted a retrospective study collecting electroclinical data of patients with STXBP1-DEE and two control groups of patients with DEEs of different etiologies and typically developing individuals matched for age and sex. We performed a (1) visual EEG assessment, (b) qEEG analysis, and (c) electrical source imaging (ESI). We quantified the relative power (RP) of four frequency bands (α β, θ, δ), in two electrode groups (anterior/posterior), and compared their averages and dynamics (standard deviation [SD] over time). The ESI was performed by applying the standard Distributed Source Modeling algorithm. We analyzed 42 EEG studies in 19 patients with STXBP1-DEE (10 female), with a median age at recordings of 9.6 years (range 9 months to 29 years). The δRP was higher in recordings of STXBP1-DEE (p < .001) compared to both control groups, suggesting the pathogenicity and STXBP1-specificity of these findings. In STXBP1-DEE, the δRP was significantly higher in the anterior electrode group compared to the posterior one (p = .003). There was no correlation between the anterior δRP and the epilepsy focus, age at recordings, and concomitant medications The ESI modeling of this activity showed a widespread involvement of the dorsomesial frontal cortex, suggesting a large corticosubcortical pathologic network. Finally, we identified two groups of recordings: cluster.1 with higher anterior δRP and low dynamics and cluster.2 with lower δRP and higher dynamics. Patients in cluster.1 had a more severe epilepsy and neurological phenotype compared to patients in cluster 2. The qEEG analysis showed a predominant frontal slow activity as a specific STXBP1 feature that correlates with the severity of the phenotype and may represent a biomarker for prospective longitudinal studies of STXBP1-DEE.

Electroencephalographic monitoring in detection and prediction of delayed cerebral ischemia due to non-traumatic subarachnoid hemorrhage

Intensive care of patients with acute non-traumatic subarachnoid hemorrhage primarily relies on diagnostics of delayed cerebral ischemia (DCI). The major difficulty in detecting DCI emerges upon suppression of wakefulness, when clinical assessment of growing neurological deficit becomes complicated. Widely used transcranial dopplerography allows solely to verify a vasospasm development not always leading to DCI exhibiting a multifactorial underlying mechanism. Electroencephalography (EEG) is the only broadly available instrumental tool ensuring a continuous monitoring of cerebral functional status including in subjects at intensive care unit. To date, non-specific EEG parameters pointing at development of acute cerebral injury were identified that provide varying diagnostic and predictive informative value in DCI. We reviewed publications aimed at assessing the data on visual and quantitative EEG parameters such as regional slowing, alpha rhythm spectral power and relative variability, alpha-to-delta power ratio, and detection of epileptiform activity. Having searched international and Russia-wide medical databases, we found only 7 publications quantitatively assessing diagnostic value of EEG monitoring, which showed that for DCI diagnosis its sensitivity ranged from 76% to 100%, and specificity – from 54% to 100%. We also present a clinical case with a 70-year-old female patient who underwent surgery for non-traumatic subarachnoid hemorrhage due to a ruptured aneurysm of the communicating segment of the right internal carotid artery. During the continuous videoEEG monitoring 2 days before clinical deterioration and appearance of ischemic changes in the right cerebral hemisphere on computed tomography scans, an ictal-interictal continuum pattern was noted to emerge. Future studies should be aimed at clarifying and validating the most informative DCI biomarkers including while recording EEG with intracranial electrodes that may contribute to development of automated algorithms for DCI detection.

Neurofeedback Reduces P300 Amplitudes to Intensely Emotive Pictures in Depressed Cancer Patients.

Objective. Electroencephalographic neurofeedback (EEG NF) or its effects on event-related potentials (ERPs) in quantitative EEG have not yet been systematically studied in cancer patients. The aim of this study was to investigate the emotional arousal and valence effects on the event-related P300 in a visual oddball paradigm by an individualized EEG alpha and theta/beta NF intervention in cancer patients and survivors (N = 18, age between 31 and 73 years). Methods. ERPs to low and high arousal target stimuli with either emotional positive or negative content and depressive state were obtained in cancer patients before and after a five-week NF intervention in a waitlist paradigm, following the consensus on the reporting and experimental design of clinical and cognitive-behavioral NF studies (CRED-nf checklist). Results. Overall, P300 amplitudes decreased significantly (p < .05) from pre to post therapy. Effects concerning high arousal stimuli with negative and positive valences were on the border to significance. Moreover, patients achieved significant relief of depressive symptoms (p < .05). Especially younger participants (<55 yrs.) benefited. Conclusions. P300 observations could reflect a therapeutic effect on brain activity level. EEG NF alleviates depressive symptoms in cancer patients. Significance. Based on these findings, further studies are needed to investigate the effects on event-related potentials by NF therapy.

Neurophysiological markers of early cognitive decline in older adults: a mini-review of electroencephalography studies for precursors of dementia.

The early detection of cognitive decline in older adults is crucial for preventing dementia. This mini-review focuses on electroencephalography (EEG) markers of early dementia-related precursors, including subjective cognitive decline, subjective memory complaints, and cognitive frailty. We present recent findings from EEG analyses identifying high dementia risk in older adults, with an emphasis on conditions that precede mild cognitive impairment. We also cover event-related potentials, quantitative EEG markers, microstate analysis, and functional connectivity approaches. Moreover, we discuss the potential of these neurophysiological markers for the early detection of cognitive decline as well as their correlations with related biomarkers. The integration of EEG data with advanced artificial intelligence technologies also shows promise for predicting the trajectory of cognitive decline in neurodegenerative disorders. Although challenges remain in its standardization and clinical application, EEG-based approaches offer non-invasive, cost-effective methods for identifying individuals at risk of dementia, which may enable earlier interventions and personalized treatment strategies.

Patients with temporomandibular disorders and chronic pain of myofascial origin display reduced alpha power density and altered small-world properties of brain networks

BACKGROUND: Chronic pain is one of the most common symptoms of temporomandibular disorders (TMD). Although its pathophysiology is still a challenge, TMD has been associated with changes in central nervous system activity related to pain modulatory capacity. OBJECTIVE: To assess the cortical activity of patients with temporomandibular disorders and chronic pain of myofascial origin using quantitative electroencephalography (qEEG) in different mental states. METHOD: This study consists of a cross-sectional study. Individuals with TMD and chronic pain and healthy controls were evaluated using qEEG in four consecutive conditions, all with closed eyes: 1) initial resting condition; 2) non-painful motor imagery task of hand movement; 3) painful motor imagery task of clenching the teeth; 4) final resting condition. RESULTS: Participants with TMD and chronic pain overall presented decreased alpha power density during baseline at rest, non-painful and painful motor imagery tasks when compared to healthy controls. Furthermore, functional brain connectivity was distinct between groups, with TMD and chronic pain showing lower small-world values for the delta (all conditions), theta (painful and non-painful motor imagery task), and alpha bands (painful motor imagery task), and an increase in the beta band (all conditions). CONCLUSION: These results suggest that TMD and chronic pain could be associated with maladaptive plasticity in the brain, which may correspond to a reduced ability to modify brain activity during different mental tasks, including painful and non-painful motor imagery.

Erratum] Brain Imaging and neurostimulation in health and disorders: status report

INTRODUCTION: Despite being considered least important for clinical practice in the pyramid of evidence for recommendations, sometimes scientists' expert opinions could help to better understand the summarization of updated publications. OBJECTIVE: To provide a major summarized update about brain imaging and stimulation of the nervous system in health and disease. METHODS: Comprehensive review developed by experts in each subarea of knowledge in neuroimaging and non-invasive stimulation of the nervous system. A team of researchers and clinic experts was invited to present an update on their area of expertise. RESULTS: In basics on brain imaging techniques, we approach general and quantitative electroencephalography, functional magnetic resonance imaging, functional near-infrared spectroscopy, and experimental paradigms in brain imaging studies. Were included associations between transcranial magnetic stimulation and electromyography, electroencephalography, and functional near-infrared stimulation to evaluate brain activity. Furthermore, we showed several actualized central and peripheral neuromodulation techniques. And finally, we presented different clinical and performance uses of non-invasive neuromodulation. CONCLUSION: To our knowledge, this is a major summarized and concentrated update about brain imaging and stimulation that can benefit neuroscience researchers and clinicians from different levels of experience.

The effects of deep TMS on purpose in life, quantitative EEG and event-related potentials in major depressive disorder

Background: Perceived purpose in life (PIL) is linked with many vital health outcomes, including Major Depressive Disorder (MDD). Methods: In this study, biomarkers associated with depression and PIL were investigated using Brain Network Activation (BNA) based quantitative electroencephalography (QEEG) and event-related potential (ERP) measures in a sample of individuals with MDD. Data were analyzed before and after a 36-session, Deep transcranial magnetic stimulation (TMS) program. Results: At baseline, the study observed that increased slow-frequency resting-state activity in the frontal and temporal regions correlated with higher levels of depression and reduced PIL. Additionally, a reduced P3b amplitude was found to predict elevated depressive symptoms. However, with the application of Deep TMS treatment notable improvements were observed in both depression (p < .001. d = 2.15) and PIL (p < .001, d = 1.59) levels. The treatment also successfully regulated resting-state QEEG (delta/beta) and ERP characteristics (P200 latency), bringing them closer to healthy levels. Conclusions: This attenuation of brain activity patterns relating to depression is encouraging as it suggests that effects were robust and are more likely to be sustained over time. This study represents the first exploration of the effects of Deep TMS on PIL and relevant QEEG and ERP biomarkers. The initial evidence suggests that Deep TMS holds promise in enhancing both PIL and neurophysiological health. Future investigations should continue exploring the utility of Deep TMS in targeting a wide range of neuropsychological and physical health conditions, leveraging objective biomarkers such as QEEG and ERP.

Quantitative Electroencephalography Biomarkers in Patients With Anti-N-methyl-D-aspartate Receptor Encephalitis: A Case–Control Study

Quantitative Electroencephalography Biomarkers in Patients With Anti-N-methyl-D-aspartate Receptor Encephalitis: A Case–Control Study

Quantitative EEG Spectral Features Differentiate Genetic Epilepsies and Predict Neurologic Outcomes.

EEG plays an integral part in the diagnosis and management of children with genetic epilepsies. Nevertheless, how quantitative EEG features differ between genetic epilepsies and neurological outcomes remains largely unknown. Here, we aimed to identify quantitative EEG biomarkers in children with epilepsy and a genetic diagnosis in STXBP1 , SCN1A , or SYNGAP1 , and to assess how quantitative EEG features associate with neurological outcomes in genetic epilepsies more broadly. We analyzed individuals with pathogenic variants in STXBP1 (95 EEGs, n =20), SCN1A (154 EEGs, n =68), and SYNGAP1 (46 EEGs, n =21) and a control cohort of individuals without epilepsy or known cerebral disease (847 EEGs, n =806). After removing artifacts and epochs with excess noise or altered state from EEGs, we extracted spectral features. We validated our preprocessing pipeline by comparing automatically-detected posterior dominant rhythm (PDR) to annotations from clinical EEG reports. Next, as a coarse measure of pathological slowing, we compared the alpha-delta bandpower ratio between controls and the different genetic epilepsies. We then trained random forest models to predict a diagnosis of STXBP1 , SCN1A , and SYNGAP1 . Finally, to understand how EEG features vary with neurological outcomes, we trained random forest models to predict seizure frequency and motor function. There was strong agreement between the automatically-calculated PDR and clinical EEG reports ( R 2 =0.75). Individuals with STXBP1 -related epilepsy have a significantly lower alpha-delta ratio than controls ( P< 0.001) across all age groups. Additionally, individuals with a missense variant in STXBP1 have a significantly lower alpha-delta ratio than those with a protein-truncating variant in toddlers ( P< 0.001), children ( P =0.02), and adults ( P< 0.001). Models accurately predicted a diagnosis of STXBP1 (AUC=0.91), SYNGAP1 (AUC=0.82), and SCN1A (AUC=0.86) against controls and from each other in a three-class model (accuracy=0.74). From these models, we isolated highly correlated biomarkers for these respective genetic disorders, including alpha-theta ratio in frontal, occipital, and parietal electrodes with STXBP1 , SYNGAP1 , and SCN1A , respectively. Models were unable to predict seizure frequency (AUC=0.53). Random forest models predicted motor scores significantly better than age-based null models ( P< 0.001), suggesting spectral features contain information pertinent to gross motor function. In summary, we demonstrate that STXBP1 -, SYNGAP1- , and SCN1A -related epilepsies have distinct quantitative EEG signatures. Furthermore, EEG spectral features are predictive of some functional outcome measures in patients with genetic epilepsies. Large-scale retrospective quantitative analysis of clinical EEG has the potential to discover novel biomarkers and to quantify and track individuals' disease progression across development.

T2 MRI visible Perivascular Spaces in Parkinson`s Disease: clinical significance and association with polysomnography measured sleep.

Poor sleep quality might contribute to the risk and progression of neurodegenerative disorders via deficient cerebral waste clearance functions during sleep. In this retrospective cross-sectional study, we explore the link between enlarged perivascular spaces (PVS), a putative marker of sleep-dependent glymphatic clearance, with sleep quality and motor symptoms in Parkinson`s disease (PD) patients. T2-weighted MRI images of 20 patients and 17 healthy control subjects were estimated visually for PVS in the basal ganglia (BG) and centrum semiovale (CSO). The patient group additionally underwent a single-night polysomnography. Readouts included polsyomnographic sleep features and slow-wave activity (SWA), a quantitative EEG marker of sleep depth. Associations between PVS counts, PD symptoms (MDS-UPDRS scores) and sleep parameters were evaluated using correlation and regression analyses. Intra- and inter-rater reproducibility was assessed with weighted Cohen`s kappa coefficient. BG and CSO PVS counts in both patients and controls did not differ significantly between groups. In patients, PVS in both brain regions were negatively associated with SWA (1-2Hz) (BG: r(15)=-0.58, padj=0.015 and CSO: r(15)=-0.6, padj=0.015). Basal ganglia PVS counts were positively associated with motor symptoms of daily living (IRR=1.05, CI [1.01, 1.09], p=0.007, padj=0.026) and antidepressant use (IRR=1.37, CI [1.05, 1.80], p=0.021, padj=0.043) after controlling for age. Centrum Semiovale PVS counts in patients were positively associated with a diagnosis of REM sleep behaviour disorder (IRR=1.39, CI [1.06 , 1.84]), p=0.018, padj=0.11). These results add evidence that sleep deterioration may play a role in impairing glymphatic clearance via altered perivascular function, potentially contributing to disease severity in PD patients.

Quantitative Electroencephalography Monitoring in Type A Aortic Dissection Surgery: A Clinical Case Review and Prospective Applications.

This review explores advanced methods for assessing perioperative cerebral function in Type A aortic dissection (TAAD) patients, with a focus on quantitative electroencephalography (QEEG). It highlights the critical issue of cerebral malperfusion, which is associated with higher mortality and poor prognosis during the perioperative phase in TAAD patients. The review centers on the utilization of QEEG as a pivotal tool for the extensive monitoring of brain function at various stages: preoperatively, intraoperatively, and postoperatively. It elaborates on the foundational principles of QEEG, including the mathematical and computational analysis of electroencephalographic signals, enriched with intuitive graphical representations of cerebral functional states. QEEG is presented as an innovative approach for the real-time, noninvasive, and reliable assessment of cerebral function. The review details the application of QEEG in monitoring conditions such as preoperative cerebral malperfusion, intraoperative deep hypothermic circulatory arrest, and postoperative recovery of cerebral function in patients undergoing TAAD treatment. Although QEEG is still in an exploratory phase for TAAD patients, it has shown efficacy in other domains, suggesting its potential in multimodal brain function monitoring. However, its broader application requires further research and technological advancements.

Default at fault? Exploring neural correlates of default mode network in children with ADHD, their unaffected siblings versus neurotypical controls: A quantitative EEG study

BackgroundSustained activation of default mode network has been implicated for momentary lapses of attention and higher errors during performance of cognitive tasks in attention deficit hyperactive disorder (ADHD) children. Despite emerging evidence indicating the genetic basis of ADHD, there is paucity of literature investigating the alteration of DMN in children with ADHD and their unaffected siblings. AimTo study the cortical sources of DMN in children with ADHD compared to their siblings and neurotypical controls. MethodsEighty-six participants (35 ADHD (12.4(±2.7) years), 16 unaffected siblings (11.8(±4.3) years) and 35 matched neurotypical controls (12.6 (±3.6) years) participated in the study. 128 channel EEG data was acquired during rest and Stroop cognitive task and analyzed for cortical source estimation using LORETA software. ResultsHigher activation of DMN and DMN associated areas were observed during encoding of the color-word stimuli in children with ADHD. Sustained activation of core DMN areas namely medial frontal gyrus, posterior cingulate gyrus, parahippocampal gyrus and inferior parietal lobule was observed across all groups. Among the three groups, distinct cortical source activation differences were identified solely in the DMN and its associated areas among children with ADHD during the task encoding phase compared to baseline. In contrast, both siblings and neurotypical controls displayed activation in fronto-parieto-temporal areas subserving executive function were also observed. ConclusionSustained activity of DMN areas with minimal activity in executive network in ADHD children and unaffected siblings during encoding of stimulus implies potential endophenotypic marker in children with ADHD compared to neurotypical controls.