PURPOSE: This study aimed to evaluate the intraoperative localization and prognostic utility of electrophysiologic monitoring for upper limb and hand muscle groups during contralateral C7 nerve transfer surgery. METHODS:...PURPOSE: This study aimed to evaluate the intraoperative localization and prognostic utility of electrophysiologic monitoring for upper limb and hand muscle groups during contralateral C7 nerve transfer surgery. METHODS: In this retrospective, dual-center study, patients with spastic hemiparesis of a single upper limb who underwent contralateral C7 nerve transfer between July 2022 and November 2023 at the First Affiliated Hospital of Soochow University and Nanjing Drum Tower Hospital were included. Sensory, motor, and muscle tone changes were assessed using free electromyography, compound muscle action potentials, somatosensory evoked potentials, and transcranial electrical stimulation motor evoked potentials. RESULTS: Ten patients (eight males and two females; mean age: 54 ± 10.7 years) were included. Free electromyography demonstrated 100% accuracy in detecting nerve traction. Stimulation of the C7 nerve elicited 100% positive compound muscle action potential responses in the triceps brachii, extensor carpi radialis brevis, and flexor carpi ulnaris muscles. All patients exhibited somatosensory evoked potential wave amplitude reductions greater than 50%, whereas latency changes were observed in 10% of cases. CONCLUSIONS: Real-time free electromyography and triggered stimulation enabled accurate localization of C5-C8 nerve roots. Somatosensory evoked potential and transcranial electrical stimulation motor evoked potential monitoring were predictive of postoperative sensory and motor function in the unaffected upper limb.
OBJECTIVE: Simple reaction time (SRT) to acoustic stimuli is a typical parameter used in the assessment of driving ability in people with epilepsy (PWE). In clinical practice, auditory SRT is commonly compared during and...OBJECTIVE: Simple reaction time (SRT) to acoustic stimuli is a typical parameter used in the assessment of driving ability in people with epilepsy (PWE). In clinical practice, auditory SRT is commonly compared during and outside of epileptiform discharges (ED). Yet, a subset of PWE also has slowed SRT outside their ED, possibly because of antiseizure medication (ASM) or disease-associated network alterations. SRT values should therefore be compared with reference values from matched controls which are currently lacking in practice. We here aimed to find a reference range of SRT in healthy controls using the same paradigm as commonly used in PWE. METHODS: We measured auditory SRT in heathy control subjects without epilepsy and a cohort of patients with epilepsy. We matched the control cohort, according to age and sex, to a cohort of PWE who had previously been recorded at our center using the same task. This allowed to compare auditory SRT between a control cohort and a cohort of PWE. RESULTS: The control group showed a significantly lower mean SRT latency and a smaller SRT variability as compared with PWE. Within the cohort of PWE, the SRT was significantly prolonged during periods with ED. Potential confounding factors, such as age, did not show any significant contribution to auditory SRT. CONCLUSIONS: Our findings demonstrate a small intrapersonal variance of SRT in the control group. Therefore, outlier SRT values in PWE during ED are likely a useful parameter for assessing driving ability.
PURPOSE: Facial nerve injury is a potential complication in intradural middle cranial fossa surgery, particularly because of dehiscence of the geniculate ganglion, exposing the nerve to thermal injury. Identifying the ge...PURPOSE: Facial nerve injury is a potential complication in intradural middle cranial fossa surgery, particularly because of dehiscence of the geniculate ganglion, exposing the nerve to thermal injury. Identifying the geniculate ganglion during surgical approaches is crucial for preserving facial nerve function. This study aimed to evaluate the feasibility and efficacy of transdural stimulation in identifying the geniculate ganglion during intradural approaches to improve the preservation of facial nerve function. METHODS: We conducted a retrospective analysis on patients who underwent surgery for middle cranial fossa lesions using intraoperative neuromonitoring including facial motor evoked potentials and transdural direct nerve stimulation of the geniculate ganglion, from January 2016 to January 2024. RESULTS: We identified eight consecutive patients with various pathologies of the middle cranial fossa who underwent surgery with direct nerve stimulation of the geniculate ganglion. Specific responses from facial muscles were registered in four out of eight patients, with stimulation intensity varying between 0.5 and 2 mA. None of the patients who underwent surgery with direct nerve stimulation experienced facial palsy. Notably, even when CT scans suggested bony covering of the geniculate ganglion, the facial nerve could still be stimulated. CONCLUSIONS: This proof-of-principle study demonstrates that transdural stimulation is a promising technique for identifying the geniculate ganglion during intradural middle cranial fossa surgery. This approach has the potential to improve preservation of facial nerve function and reduce the risk of postoperative facial palsy.
INTRODUCTION: Positive spike wave (PSW) discharges on EEG are well-documented in neonates, but data regarding their significance in other populations are limited. This study aimed to assess the clinical significance of P...INTRODUCTION: Positive spike wave (PSW) discharges on EEG are well-documented in neonates, but data regarding their significance in other populations are limited. This study aimed to assess the clinical significance of PSW in children aged 1 month to 19 years at a single tertiary care center over approximately three decades. METHODS: Clinical information of children with focal PSW ( n = 326) was compared with control patients with focal negative interictal epileptiform discharges ( n = 898). RESULTS: From 77,500 pediatric EEGs in our laboratory from 1992 to 2020, PSW were identified in 445 (0.57%) children, of which 326 met inclusion criteria. Positive spike waves were located in the following brain regions: occipital (139), central (65), frontal (63), temporal (43), parietal (9), and centro-temporal (7). Positive spike wave patients had a younger median age of seizure onset than control patients (1.1 years [0.30, 4.00] versus 4 years [1.3, 7.5], P < 0.001).Logistic regression analysis confirmed that PSW were associated with high odds of seizures [odds ratios (OR) 3.78; CI: 2.14-2.14; P < 0.005], epilepsy [OR 2.05; CI: 1.39-1.39; P < 0.005], and drug-resistant epilepsy, [OR 3.51; CI: 2.67-2.67; P < 0.005]. Furthermore, PSW correlated with a greater odd of developmental delay [OR 3.69; CI: 2.77-2.77; P < 0.005], school difficulties [OR 2.85; CI: 2.07-2.07; P < 0.005], abnormal neurologic exam [OR 2.8; CI: 2.15-2.15; P < <0.005], and structural brain abnormalities [OR 1.74; CI: 1.32-1.32; P < 0.005], such as malformation of cortical development, compared with control patients. CONCLUSIONS: Positive spike waves on pediatric EEG are associated with congenital or acquired brain abnormalities and less favorable seizure and neurodevelopmental outcomes.
PURPOSE: Cathodal transcranial direct current stimulation (c-tDCS), a noninvasive neuromodulation technique, is effective in reducing cortical excitability in patients with drug-resistant epilepsy.This study aimed to exa...PURPOSE: Cathodal transcranial direct current stimulation (c-tDCS), a noninvasive neuromodulation technique, is effective in reducing cortical excitability in patients with drug-resistant epilepsy.This study aimed to examine the impact of c-tDCS on seizure frequency, Liverpool Seizure Severity Scale, and electroencephalography in patients with drug-resistant temporal lobe epilepsy. METHODS: A randomized, double-blind, placebo-controlled clinical trial was conducted on 30 patients with temporal lobe drug-resistant epilepsy. The patients were randomized into two groups. Group A received a once-daily split session (20 minutes stimulation-20 minutes break-20 minutes stimulation) on five consecutive days of 1 mA c-tDCS over the side of most frequent interictal epileptiform discharges or the area of suspected ictal onset. Group B underwent the sham sessions. RESULTS: A statistically significant reduction in seizure frequency, Liverpool Seizure Severity Scale, and epileptiform discharges on the EEG record was detected in the c-tDCS group after one month of the five daily sessions. CONCLUSIONS: In patients with temporal lobe drug-resistant epilepsy, c-tDCS improved seizure control by lowering seizure frequency, severity, and epileptiform discharges in the EEG for up to one month after the sessions. SIGNIFICANCE: This confirmatory study is consistent with several previous studies showing the efficacy of c-tDCS in reducing seizure frequency in patients with temporal lobe drug-resistant epilepsy.
J Clin Neurophysiol
· 2025 Jul · PMID 40673667
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Deep brain stimulation (DBS) of the anterior nucleus of the thalamus is an FDA-approved therapy for drug-resistant focal epilepsy. Recent advances in device technology, thalamic stereotactic-EEG, and chronic sensing have...Deep brain stimulation (DBS) of the anterior nucleus of the thalamus is an FDA-approved therapy for drug-resistant focal epilepsy. Recent advances in device technology, thalamic stereotactic-EEG, and chronic sensing have deepened our understanding of corticothalamic networks in epilepsy and identified promising biomarkers to guide and personalize DBS. In this review, we examine electrophysiological, imaging, and clinical biomarkers relevant to epilepsy DBS, with a focus on their potential to support seizure detection, target engagement, network excitability tracking, and seizure risk forecasting. We highlight emerging insights from thalamic sEEG, including both passive recordings and active stimulation protocols, which enable mapping and modulation of large-scale brain networks. The capabilities of clinical sensing-enabled DBS systems are reviewed. As device functionality and biomarker discovery evolve, concerted translational efforts are needed to realize a new paradigm of personalized DBS in epilepsy.
Dravet syndrome is an intractable developmental and epileptic encephalopathy caused primarily by SCN1A haploinsufficiency, leading to impaired NaV1.1 sodium channel function and reduced inhibitory signaling. Despite trea...Dravet syndrome is an intractable developmental and epileptic encephalopathy caused primarily by SCN1A haploinsufficiency, leading to impaired NaV1.1 sodium channel function and reduced inhibitory signaling. Despite treatment with antiseizure medications, many patients remain drug resistant, necessitating alternative approaches such as neuromodulation. Responsive neurostimulation (RNS), which detects and responds to abnormal brain activity in real time, has shown promise in generalized epilepsy by targeting the thalamus. Thalamic stimulation can disrupt abnormal oscillatory activity, potentially reducing seizure frequency and severity. This report presents a 7-year-old girl with Dravet syndrome in the setting of a pathogenic SCN1A variant and drug-resistant epilepsy, who experienced numerous generalized seizures daily. After extensive testing and multiple antiseizure medication trials, RNS was implanted with bilateral centromedian nucleus of the thalamus depth electrodes. At her most recent clinic visit, she exhibited a 50% to 75% reduction in seizure frequency, with resolution of myoclonic and myoclonic-atonic seizures. Her family reported significant reductions in rescue medication use, seizure duration, and seizure severity after RNS implantation. This case adds to the growing evidence supporting the use and safety of RNS in pediatric patients with drug-resistant generalized epilepsy and is the first reported instance of RNS treatment in a patient with Dravet syndrome. Although the initial results are promising, further research is needed to explore the long-term efficacy, safety, and neurodevelopmental impacts of RNS in this population. This case highlights the importance of continued research and clinical innovation in neuromodulation therapies for Dravet syndrome.
INTRODUCTION: Prior findings on direct intracranial electrical stimulation (iES) of the human orbitofrontal cortex (OFC), which includes the orbital and ventromedial prefrontal regions, have been mixed, with several repo...INTRODUCTION: Prior findings on direct intracranial electrical stimulation (iES) of the human orbitofrontal cortex (OFC), which includes the orbital and ventromedial prefrontal regions, have been mixed, with several reports lacking replication. We aimed to clarify the effects of iES in the OFC. METHODS: We analyzed data from 608 stimulations across 277 OFC site pairs (352 sites total) in 49 patients collected over 17 years of our practice. RESULTS: We found 24.4% of sites as responsive to iES, with subjects reporting visual and olfactory sensations. However, post hoc analysis revealed that these responses largely originated from the stimulation of nearby non-OFC optic and olfactory structures. After applying quality controls, stimulation of only 0.6% of OFC sites (2 sites, 2 patients) produced changes in subjective domain, while 99.4% had no reportable effects. Contrary to earlier studies, we found no evidence of valence lateralization or functional organization within the OFC. CONCLUSIONS: Our findings suggest that the electrical perturbation of OFC is largely silent and does not lead to reportable change in the subjective state of the individual. SIGNIFICANCE: Orbitofrontal cortex is a higher transmodal cortical area. The variability and limited replicability of reported effects from prior publications and the inconsistencies in the extant literature about OFC stimulations can be attributed to methodological shortcomings.
The orbitofrontal cortex (OFC) is a highly interconnected region, cytoarchitectonically diverse. Seizures involving the OFC present significant diagnostic challenges because of their variable semiological features, which...The orbitofrontal cortex (OFC) is a highly interconnected region, cytoarchitectonically diverse. Seizures involving the OFC present significant diagnostic challenges because of their variable semiological features, which often overlap with those typically attributed to frontal and temporal epilepsies. Moreover, OFC seizures semiology is shaped by the epileptogenic zone network (EZN), involving either ictal propagation or reconfiguration of functional networks. We systematically reviewed 87 patients presenting seizures involving the OFC to analyze semiological profiles using the latest International League Against Epilepsy classification. We found that seizures with EZN restricted to the OFC displayed sparse semiology, including hyperkinetic behaviors, verbal automatisms, and frequent sleep association, while extended EZN seizures exhibited richer semiological profiles, varying according to EZN distribution. Temporal involvement correlated with more auras, oro-alimentary automatisms, and occurred more often with sleep, while frontal and insular participation involved hyperkinetic behaviors with more mimic and gestural automatisms. Semiological profiles of the OFC-restricted EZN seizures are concordant with propagation patterns that align with the functional connectivity of the OFC: lateral OFC seizures tend to propagate to the lateral and mesial frontal lobe while medial OFC seizures propagated to temporal lobe, either medial or polar. Despite population-level observations, semiological profiles alone seem insufficient for delimitation of extension or distribution of EZN. According to seizure semiology, "frontal" like profiles appear more frequent (∼2/3 of patients) while "temporal" like profiles were more associated with an extended EZN. These findings underscore the importance of comprehensive presurgical evaluations, to delineate EZN extension and distribution in seizures involving the OFC.
Recent advances in artificial intelligence (AI) and machine learning (ML) can revolutionize neuromodulation therapies for drug-resistant epilepsy. Successful incorporation of AI/ML methods into the management of epilepsy...Recent advances in artificial intelligence (AI) and machine learning (ML) can revolutionize neuromodulation therapies for drug-resistant epilepsy. Successful incorporation of AI/ML methods into the management of epilepsy can guide treatment decisions, enable interventions to adapt to dynamic epileptic networks, and hopefully improve patient outcomes. We introduce some common concepts in ML, focusing on neural networks, particularly convolutional and recurrent neural networks, and support vector machines, because these methods have been commonly applied to epilepsy neuromodulation. We discuss current AI/ML applications in neuromodulation, encompassing vagus nerve stimulation, responsive neurostimulation, and deep brain stimulation, for the treatment of epilepsy. We consider how AI/ML methods leverage large data sets to enhance patient-specific epileptic network analysis, optimize stimulation targets, and refine closed-loop systems for real-time seizure detection and termination. AI/ML applications extend to recognizing autonomic and behavioral seizure surrogates, detecting interictal epileptiform activity, and forecasting seizures for preemptive interventions. Furthermore, AI-powered neuroimaging analysis can enhance segmentation accuracy for precise electrode placement, which can improve neuromodulation outcomes. We review which AI/ML tools have been applied to each problem, as well as their relative performance. Challenges remain, however, in translating AI/ML models into clinical settings due to interpatient variability and limited real-world validation. Future directions include integrating behavioral signals, developing AI-assisted clinical decision tools, and refining energy-efficient neurostimulation designs. Large language models and generative AI hold promise for optimizing patient-specific neuromodulation strategies. However, further research is required to validate AI/ML applications in clinical practice, enhance model generalizability, and address ethical concerns surrounding data privacy and AI-driven decision making.
Tesh RA, Zahoor A, Banks J
… +20 more, Gallagher K, Eckhardt CA, Sun H, Karakis I, Katyal R, Williams J, Nayak C, Herlopian A, Ng MC, Greenblatt AS, Meyers E, Westmeijer M, Harrison DS, Ganglberger W, Galina Gheihman, Fan T, Struck AF, Sheikh IS, Nascimento FA, Westover MB
J Clin Neurophysiol
· 2026 Mar · PMID 40601962
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PURPOSE: Visual EEG Confusion Assessment Method-Severity (VE-CAM-S) quantifies encephalopathy severity based on electroencephalography features. This study evaluated inter-rater reliability among experts using the VE-CAM...PURPOSE: Visual EEG Confusion Assessment Method-Severity (VE-CAM-S) quantifies encephalopathy severity based on electroencephalography features. This study evaluated inter-rater reliability among experts using the VE-CAM-S scale. METHODS: Nine experts from six institutions independently reviewed 32 15-second electroencephalography samples in an online test, assessing 29 features (16 in the VE-CAM-S and 13 additional, or "VE-CAM-S+"). A consensus of three experts served as the gold standard. Performance was measured by the median Matthews correlation coefficient between expert and gold-standard VE-CAM-S+ scores, along with average sensitivity and specificity. Qualitative analysis identified common feature-recognition errors affecting scores. RESULTS: Experts achieved a median Matthews correlation coefficient of 0.82 [95% CI: 0.74-0.99]. Specificity exceeded 90% for most features except background β (87%) and generalized delta (71%). Sensitivity was ≥65% except for burst suppression with epileptiform activity (61%), extreme delta brush (EDB; 61%), posterior dominant rhythm (50%), background α (59%) and β (42%). Common errors included missing subtle findings, confusing features, and misidentifying extreme delta brush. CONCLUSIONS: This pilot study offers some initial support for the reliability of VE-CAM-S+ scoring. The largest errors occurred when experts missed or falsely identified features with higher weight in the VE-CAM-S. Encephalopathy grading through VE-CAM-S may be improved by breaking high-stakes features into smaller parts, creating a "cheat sheet" with scored examples, and designing teaching materials.
Al-Salahat A, Dilsaver DB, Chen YT
… +3 more, Sharma R, Kapoor N, Bernitsas E
J Clin Neurophysiol
· 2026 Mar · PMID 40601961
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PURPOSE: Intraoperative neuromonitoring (IONM) is a valuable tool to monitor the neural axis during various procedures and guide intervention aimed at managing operative complications. The literature lacks large scale da...PURPOSE: Intraoperative neuromonitoring (IONM) is a valuable tool to monitor the neural axis during various procedures and guide intervention aimed at managing operative complications. The literature lacks large scale data on trends and demographic disparities in IONM use in the United States. METHODS: Data were abstracted from the 2008-2021 National Inpatient Sample. Hospitalizations for neurosurgical (spinal, craniotomy, carotid artery, cranial/peripheral nerve), cardiac/vascular, and head/neck/thyroid procedures were identified and stratified by IONM use. Logistic regression models were estimated to assess disparities and trends in IONM use. Multivariable models adjusted for patient- and facility-level characteristics. RESULTS: From 2008 to 2021, the rate of IONM use increased significantly in neurosurgical (3.69% to 18.62%, p < 0.001) and cardiac/vascular procedures (0.018% to 0.6%, p < 0.001). IONM use for head/neck/thyroid procedures increased steadily until 2014 and then declined ( p < 0.001). Compared with hospitalizations of White patients, Black (aOR = 0.87, 95% CI: 0.81-0.94) and Hispanic (aOR = 0.88, 95% CI: 0.81-0.96) patients were associated with lower odds of IONM use during craniotomy. Lower incomes (0-25th quartile) were associated with lower odds of IONM use in both spinal (aOR = 0.83, 95% CI: 0.78-0.88) and craniotomy procedures (aOR = 0.78, 95% CI: 0.72-0.85). CONCLUSIONS: There is a growing demand for IONM to enhance the safety of various procedures, indicating a need for neurologists and technologists with this expertise. In addition, we found significant racial/ethnic and socioeconomic disparities in IONM use. These findings can be valuable for health care administrators and policymakers to address disparities in the access to IONM.
PURPOSE: To determine if incorporating neuroanatomic or intersubject variation in the occurrence rate of intracranial high-frequency oscillations improves its diagnostic performance for localization of epileptogenic zone...PURPOSE: To determine if incorporating neuroanatomic or intersubject variation in the occurrence rate of intracranial high-frequency oscillations improves its diagnostic performance for localization of epileptogenic zone (EZ). METHODS: Five minutes of awake stereo-electroencephalography data from 59 patients were analyzed. High-frequency oscillations were analyzed using three different normalization methods: rate per minute, by neuroanatomic region across the patient population, and patient-wise. Generalized linear mixed effects models were trained in patients with good seizure outcomes after epilepsy surgery (higher confidence in the clinical localization of EZ) and tested in patients with poorer outcomes (validation set approach). RESULTS: The generalized linear mixed model with region-wise normalization across the patient population best localized the EZ (highest area under the curve 0.69), closely followed by the rate per minute (0.68). In the test subgroup, the optimal generalized linear mixed model predicted EZ in individual patients with an accuracy of 0.18 to 0.86, sensitivity of 0.05 to 1.00, and specificity of 0.12 to 0.95. In patients with poorest performance of the generalized linear mixed model, although the electrode contacts within EZ were correctly identified, there was a high number of false positives (model-predicted electrode contacts lying outside clinically ascertained EZ). Model performance varied across neuroanatomic regions, with the highest accuracy in the medial/orbital frontal (0.8), lateral temporal (0.78), and lateral parietal (0.76) regions. CONCLUSIONS: Normalizing the high-frequency oscillation occurrence rate by neuroanatomic region improves its diagnostic performance as an interictal biomarker of EZ location. High-frequency oscillations are more likely to reliably identify electrode contacts within EZ in medial/orbital frontal lobe and temporal neocortex.
Over the past 20 years, responsive neurostimulation (RNS), a closed-loop device for treating certain forms of drug-resistant focal epilepsy, has become ensconced in the epileptologist's therapeutic armamentarium. Through...Over the past 20 years, responsive neurostimulation (RNS), a closed-loop device for treating certain forms of drug-resistant focal epilepsy, has become ensconced in the epileptologist's therapeutic armamentarium. Through neuromodulatory effects, RNS therapy gradually reduces seizures over years, providing diagnostically valuable intracranial recordings along the way. However, the neuromodulatory potential of RNS therapy has not been fully harnessed. Seizure reduction is often slow, outcomes vary across individuals and defy prognostication, seizure freedom is uncommon, and many patients do not derive significant benefit. These limitations may stem from the "black box" nature of RNS therapy. The antiseizure mechanism(s) of RNS remain poorly understood, and, in the absence of first principles to inform selection of the candidates most likely to benefit, the ideal brain regions to target, and the most effective stimulation parameters, contemporary use of RNS therapy is largely empiric. Fortunately, recent advances in neuroimaging, neurophysiology, artificial intelligence, and engineering have made the goal of rational, personalized neurostimulation a near-term reality. Here, we review recent progress toward this goal, focusing on novel approaches to patient selection, brain network topology, state-dependent effects, and stimulation parameter optimization. By considering the who, where, when, and how of RNS, we highlight emerging paradigm shifts that will help usher in a new age of RNS therapy that is more personalized and more effective.
INTRODUCTION: In neuromuscular diseases, respiratory failure is a major complication. Pulmonary function tests are generally used to assess respiratory function but can be influenced by a number of factors. Nerve conduct...INTRODUCTION: In neuromuscular diseases, respiratory failure is a major complication. Pulmonary function tests are generally used to assess respiratory function but can be influenced by a number of factors. Nerve conduction studies of the phrenic nerve (PN) is a simple, noninvasive, and safe method to assess diaphragm compromise in neuromuscular diseases. METHODS: A group of 132 (78 males) healthy subjects, aged between 23 and 90 years, was studied, with bilateral stimulation of the PN, with recording of diaphragm motor responses. Anthropometric variables (sex, age, height, and weight) were collected, and their influence on diaphragm motor response was assessed. Side-to-side differences were also analyzed. RESULTS: PN compound muscle action potential (CMAP) had significantly higher amplitude and area on the left side. Men had longer latency, and higher amplitude and area when compared with women, on both sides. Age was a significant factor influencing CMAP latency, with an average increase of 0.25 ms per decade of life. In men, a latency longer than 9.5 ms and a CMAP amplitude lower than 0.62 mV should be considered abnormal, while in women, the values are 8.5 ms and 0.48 mV, respectively. CONCLUSIONS: PN conduction studies offer a simple and reliable technique readily applicable in clinical settings. Diaphragm CMAP parameters are significantly influenced by the anthropometric variables of sex and age. Notably, CMAP amplitude and area are greater for the left PN.