Journal Of Clinical Neurophysiology[JOURNAL]
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200 papers
Hardware Technology for Point-of-Care EEG: A Comprehensive Review.
Herman ST
J Clin Neurophysiol · 2026 Mar · PMID 41773894 · Publisher ↗
Rapid or point-of-care (POC) EEG devices, bolstered by advancements in portability, ease of use, wireless technology, and artificial intelligence, are transforming the EEG field. Increasing demand for immediate neurophys...
Rapid or point-of-care (POC) EEG devices, bolstered by advancements in portability, ease of use, wireless technology, and artificial intelligence, are transforming the EEG field. Increasing demand for immediate neurophysiologic diagnosis, previously limited by the operational complexities and specialized personnel required for traditional EEG, has driven these critical shifts. These innovations extend EEG's reach beyond traditional neurophysiology labs to diverse clinical settings, including emergency departments, intensive care units, remote locations, and homes. POC EEG is particularly valuable for diagnosing acute neurologic emergencies such as nonconvulsive status epilepticus and nonconvulsive seizures, traumatic brain injury, and stroke, enabling faster seizure detection, improved triage, and timely treatment. POC EEG systems facilitate rapid acquisition of clinically acceptable EEG by nonexperts, including physicians and other health care providers, emergency personnel, nurses, and in some cases, remote caregivers and patients. Bedside interpretation is augmented by real-time artificial intelligence algorithms. POC EEG hardware, including its sensors, headsets, amplifiers, connectivity, form factor, and power, diverges significantly from conventional EEG systems. These modifications are explicitly engineered to optimize rapid deployment, patient comfort, and operational simplicity in resource-constrained or time-sensitive scenarios. The adaptations, however, may necessitate trade-offs in signal quality, flexibility, channel count, reliability, and cost compared with laboratory-grade systems. Understanding these inherent differences and how hardware designs address them is critical for selecting the optimal POC EEG technology for a specific use.
Rapid-EEG Technologies in Comprehensive Neuromonitoring.
Kalkach-Aparicio M, Struck AF
J Clin Neurophysiol · 2026 Mar · PMID 41773893 · Publisher ↗
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Subcortical Stimulation for Functional Brain Mapping: A Systematic Review.
Safa A, Sabsevitz D, Mulone MF … +12 more , Feyissa AM, Mirsattari SM, Garg I, Wolf R, Gauthier P, Chaichana K, Grewal SS, Clark V, Byrne R, Quinones-Hinojosa A, Tatum WO, Freund BE
J Clin Neurophysiol · 2026 Feb · PMID 41740006 · Publisher ↗
PURPOSE: Subcortical functional brain mapping is a valuable technique, especially involving lesions within or near white matter tracts. Motor and language deficits caused by intraoperative damage to these subcortical fib...
PURPOSE: Subcortical functional brain mapping is a valuable technique, especially involving lesions within or near white matter tracts. Motor and language deficits caused by intraoperative damage to these subcortical fibers are associated with worse outcomes. However, there are variable approaches to performing subcortical functional brain mapping. This systematic review was performed to better understand indications and optimal stimulation parameters. METHODS: A systematic review was performed by PRISMA guidelines, using PubMed, Scopus, and Medline databases. Search dates ranged from inception to November 30th, 2024. Studies included adults who underwent subcortical electrical stimulation for functional brain mapping. RESULTS: A total of 55 articles (249 patients, mean age 44.8 years, 114 female) were included. The most common pathology was brain tumor (96.3%), primarily gliomas and metastases, and 24.4% of all cases had a history of epilepsy. The most frequently mapped white matter tracts were the arcuate fasciculus, corticospinal/pyramidal tract, and inferior fronto-occipital fasciculus, involving motor, language, and cognitive functions. Bipolar stimulation (50-60 Hz, 0.5-1 millisecond, 1-10 mA) was preferred over monopolar stimulation. Among 147 patients with outcome data, 89.1% did not suffer permanent adverse outcomes including neurologic deficits, although long-term outcomes were inconsistently reported. CONCLUSIONS: The methodologic variability of subcortical functional brain mapping and lack of long-term follow-up reported limits determination of optimal parameter selection for electrical stimulation although common trends are reported. Functional brain mapping approaches may be guided by the tract and network involved. Further studies are needed to develop a standardized approach and more definitive guideline to its performance.
Performance of Automated Detection Software in Absence Seizures.
Reus EEM, van der Vloed AP, Helling RM … +2 more , Visser GH, Cox F
J Clin Neurophysiol · 2026 Feb · PMID 41712934 · Publisher ↗
PURPOSE: Absence seizures are common in children with idiopathic generalized epilepsies. Identifying absence seizures in EEG using automated detection software offers potential efficiency gain. METHODS: This study assess...
PURPOSE: Absence seizures are common in children with idiopathic generalized epilepsies. Identifying absence seizures in EEG using automated detection software offers potential efficiency gain. METHODS: This study assessed Persyst's performance in detecting absence seizures (≥3 seconds) in prolonged pediatric EEGs. Two detection modules were used: seizure detection (most sensitive settings) and spikeburst detection which detects 'bursts' of interictal epileptiform discharges (≥1 spike per second) with a minimal duration of 1, 2 or 3 seconds. RESULTS: Eighty-one EEG records from 69 patients were analyzed. Seizure detections sensitivity is 78%, spikebursts sensitivity is 95% (1 second), 77% (2 seconds) and 61% (3 seconds). Detection rate of both modules increased to 99% for absences lasting more than 9 seconds. Median false positive rates are 24 per 24 hours (range 0-60) for seizure detection and 23 (range 0-293), one (range 0-36) and zero (range 0-19) for the spikeburst module with duration of respectively 1, 2 or 3 seconds, primarily due to interictal discharges. CONCLUSION: Spikeburst module with a threshold duration of 2 seconds represents the most feasible compromise between sensitivity and clinical usability.
Yield of Hyperventilation and Other Activation Procedures and Study Parameters in Facilitating Epileptiform Discharges.
Denhard KA, Quigg M, Axeen ET
J Clin Neurophysiol · 2026 Feb · PMID 41705827 · Publisher ↗
PURPOSE: Hyperventilation (HV) during EEG was restricted during the COVID-19 pandemic. The authors compared EEGs with and without HV to place HV in context of other factors that precipitate epileptiform abnormalities (EA...
PURPOSE: Hyperventilation (HV) during EEG was restricted during the COVID-19 pandemic. The authors compared EEGs with and without HV to place HV in context of other factors that precipitate epileptiform abnormalities (EA). The authors hypothesized HV would not significantly affect the sensitivity of routine EEG in children and adults. METHODS: The authors reviewed routine EEGs completed between March 2018 and March 2022 in subjects older than 4 years. The primary outcome variable was EA (seizures and epileptiform discharges). In a subset of patients with serial EEGs with and without HV, the authors compared intrasubject appearance of EA (McNemar test). The authors then evaluated regression models with the outcome of EA (present or absent) against independent variables of HV, EEG duration, photic stimulation, sleep deprivation, sleep, and patient-related variables of age, sex, and anti-seizure medication burden. RESULTS: Of 659 patients (806 EEGs), 180 had EA (27%). No adults had HV-activated EA. 64 of 659 patients (9.7%) had repeated EEGs both with and without HV; 34 of these (53%) had EA with HV, and 26 (41%) had EA without HV (P = 0.077, McNemar test). anti-seizure medication burden, longer recording, and HV all had significant positive odds ratios on the prevalence of EA. Sleep deprivation had a positive nonsignificant odds ratio. CONCLUSIONS: Sleep deprivation, longer recording, and HV favored EA after accounting for age and epilepsy severity. Because no adults had EA with HV, the findings suggest that HV in adults can be an elective activation procedure during EEG; sleep deprivation and longer duration recordings, in contrast, provide increased yields of EA.
Monitoring Reinnervation and Neuroplasticity After Neurotization Using Needle Electromyography.
Brušáková Š, Humhej I, Lodin J … +2 more , Ceé J, Holečková I
J Clin Neurophysiol · 2026 Feb · PMID 41678273 · Publisher ↗
PURPOSE: Brachial plexus injuries show variable outcomes after nerve transfer surgery. Recovery depends not only on axonal regeneration but also on cortical plasticity. Although neuroimaging can detect such changes, its...
PURPOSE: Brachial plexus injuries show variable outcomes after nerve transfer surgery. Recovery depends not only on axonal regeneration but also on cortical plasticity. Although neuroimaging can detect such changes, its clinical utility is limited. Needle electromyography offers a reproducible, low-cost method to assess reinnervation and synkinetic activity as potential markers of neuroplasticity. METHODS: We conducted a longitudinal observational study of 21 patients who underwent 34 proximal nerve transfers (2012-2020) to restore shoulder and elbow function after traumatic brachial plexus injury. Serial electromyography was performed at 3- to 9-month intervals over ≥36 months, using dual-channel recordings to assess spontaneous activity, motor unit potentials, and synkineses. Functional outcomes were measured using the MRC scale, goniometry, modified Mallet scale, and DASH questionnaire. RESULTS: Mean age was 36.1 years; 86% were male. Root avulsions occurred in 43%, panavulsion in 10%. Median time from trauma to surgery was 147 days. Functional success (MRC ≥3/5 with adequate ROM) was achieved in 58.8% of transfers. Early reinnervation (<6 months) occurred in 53% and correlated with greater muscle strength (Rs = 0.53, p < 0.01). Synkineses resolution occurred in 29% and correlated negatively with time to surgery (Rs = -0.50, p = 0.005). Absence of synkineses was associated with better outcomes (60 vs. 40%, p = 0.07). CONCLUSIONS: Needle electromyography enables systematic, accessible tracking of reinnervation and synkineses. Resolution of synkineses may indicate functional cortical reorganization and support improved recovery. This approach warrants further prospective validation.
Multimodal Intraoperative Neurophysiologic Monitoring Including Transcranial Motor Evoked Potentials for the Detection of Cerebral Ischemia During Carotid Endarterectomy.
Gummi R, Hirschauer T, Chang F … +8 more , Tippur A, Keroles M, Meyers N, Nguyen V, Lee L, Cho SC, López JR, Le S
J Clin Neurophysiol · 2026 Feb · PMID 41637738 · Publisher ↗
PURPOSE: Carotid endarterectomy (CEA) is a common surgical intervention, but the perioperative stroke risk may be as high as 12%, with an average reported rate approximately 3%. Intraoperative neurophysiologic monitoring...
PURPOSE: Carotid endarterectomy (CEA) is a common surgical intervention, but the perioperative stroke risk may be as high as 12%, with an average reported rate approximately 3%. Intraoperative neurophysiologic monitoring (IONM) can provide real-time feedback to guide the surgical team on whether or not to place a temporary shunt to reduce the length of time that cerebral blood flow is interrupted. In this study, the authors assessed the utility of adding transcranial motor evoked potentials (tcMEPs) to other IONM modalities in early detection of cerebral ischemia during CEAs. METHODS: The authors conducted a retrospective review of CEA cases from 2010 to 2020 at this center and included all CEA cases with electroencephalogram (EEG), somatosensory evoked potentials (SSEPs) and tcMEPs. The authors analyzed the IONM reports for case details. The primary study end points were types of IONM changes and their relative onsets to carotid occlusion. RESULTS: The authors identified 254 patients who underwent 274 CEAs using multimodal IONM. In 35 (12.7%) cases, there were critical IONM changes with 33 (12.0%) demonstrating changes during clamping of the carotid artery. Of these 35 cases, changes in both SSEPs and tcMEPs were observed in 20 (57.1%), only SSEP changes in 8 (22.9%), and only tcMEP changes in 2 (5.7%). In 5 cases, tcMEP loss was noted to precede other IONM changes. In total, 82% of significant changes were observed within the first 10 minutes of carotid clamping. CONCLUSIONS: This large cohort study shows that multimodal IONM with tcMEPs can contribute to the early detection of cerebral ischemia during CEA.
Prolonged Mismatch Negativity Latencies in Intensive Care Unit Patients With Active Delirium.
Chen YC, Chang HJ, Chang CW … +3 more , Li JL, Lu H, Cheng CH
J Clin Neurophysiol · 2026 Jan · PMID 41615169 · Publisher ↗
INTRODUCTION: Delirium is a common and serious complication in critically ill patients, associated with higher mortality, prolonged intensive care unit (ICU) stays, and cognitive impairments. Furthermore, renal dysfuncti...
INTRODUCTION: Delirium is a common and serious complication in critically ill patients, associated with higher mortality, prolonged intensive care unit (ICU) stays, and cognitive impairments. Furthermore, renal dysfunction is a well-recognized risk factor for delirium in the ICU. Although previous studies have explored the neurophysiologic characteristics of delirium, few have examined brain activity during active delirium episodes. To address this gap, this study aimed to use mismatch negativity (MMN)-an electrophysiologic marker of the brain's automatic ability to detect environmental changes-to deepen the understanding of the pathophysiology and phenomenology of delirium in ICU patients with renal dysfunction. METHODS: An auditory oddball paradigm, consisting of frequent standard tones and infrequent deviant tones, was presented to critically ill patients with renal dysfunction during event-related potential recordings. MMN was obtained by subtracting the event-related potential response to deviant stimuli from that of standard stimuli and was compared between patients with and without delirium. In addition, the authors examined the relationships between MMN, cognitive function, and disease severity. Finally, they assessed whether MMN could predict key clinical outcomes at ICU discharge. RESULTS: ICU patients with delirium exhibited significantly prolonged MMN latencies compared with those without delirium (P = 0.005, effect size = 0.67). Moreover, more delayed MMN latencies showed a trend toward an association with greater delirium severity. However, MMN did not predict key clinical outcomes on ICU discharge. CONCLUSIONS: Critically ill patients with renal dysfunction exhibit prolonged MMN latencies during delirium episodes compared with those without delirium, suggesting altered neural processing in this population.
Diagnostic Utility of Medial Dorsal Cutaneous Sensory Response and the Medial Dorsal Cutaneous-To-Radial Amplitude Ratio (MDRAR) in Diabetic Polyneuropathy.
Baran A, Gençler OS, Akın S
J Clin Neurophysiol · 2026 Jan · PMID 41615096 · Publisher ↗
PURPOSE: This study aimed to assess the diagnostic utility of the medial dorsal cutaneous (MDC) nerve and the medial dorsal cutaneous-to-radial amplitude ratio (MDRAR) in diabetic polyneuropathy (DP). METHODS: Seventy-fo...
PURPOSE: This study aimed to assess the diagnostic utility of the medial dorsal cutaneous (MDC) nerve and the medial dorsal cutaneous-to-radial amplitude ratio (MDRAR) in diabetic polyneuropathy (DP). METHODS: Seventy-four patients clinically diagnosed with DP and 40 healthy controls underwent nerve conduction studies (NCS), including sural, radial, medial plantar (MP), and MDC sensory recordings. Most patients had recent-onset, mild-to-moderate DP. Sural-to-radial amplitude ratio (SRAR), medial plantar-to-radial amplitude ratio (MPRAR), and MDRAR were calculated. Minimal tibial F-wave latencies were height-corrected, and sural amplitudes were age-corrected. Diagnostic cut-off values were established by ROC analysis. Values below the cut-off, as well as absent responses, were classified as abnormal, and sensitivity and specificity were calculated. RESULTS: A sural SNAP <6 µV demonstrated 42% sensitivity and 100% specificity. A minimal tibial F-wave latency ≥50 ms had 61% sensitivity and 100% specificity. For SRAR, a cut-off ≤0.40 yielded 49% sensitivity and 97% specificity; the 0.34 cut-off produced 38% sensitivity and 100% specificity, while the 0.21 cut-off yielded 19% sensitivity and 100% specificity. MPRAR and MDRAR demonstrated higher sensitivities (61 and 68%) but lower specificities (82 and 75%). Sural responses were obtainable in 82% of patients, whereas MP and MDC responses were recorded in 50 and 39%, respectively. CONCLUSIONS: MDRAR did not provide additional diagnostic value as a stand-alone electrophysiological parameter; however, bilateral absence of MDC responses emerged as a valuable marker of early distal involvement in DP. Further studies in selected patient groups are warranted to clarify the diagnostic contribution of MDRAR, particularly in early-stage and predominantly axonal forms of DP.
Clusters in Thalamic iEEG Spectral Features Reveal Sleep/Wake Differences Over Time.
Burdette D, Patra S, Morrell M … +1 more , Johnson L
J Clin Neurophysiol · 2026 Jul · PMID 41493069 · Full text
PURPOSE: The thalamus is a target for neurostimulation in epilepsy based on its extensive reciprocal connectivity with the cortex and subcortical areas and putative participation in a broader seizure network. In focal ne...
PURPOSE: The thalamus is a target for neurostimulation in epilepsy based on its extensive reciprocal connectivity with the cortex and subcortical areas and putative participation in a broader seizure network. In focal neocortical onset epilepsies, costimulation of the cortex and thalamus may provide an opportunity to modulate two nodes of a seizure network. Given the central role of the thalamus in sleep oscillations and regulation of consciousness, as well as the fundamental interaction between sleep and epilepsy, consideration of sleep/wake cycles may be important when treating patients with corticothalamic stimulation. METHODS: This single-center retrospective study included 30 patients with focal seizures treated with cortical and thalamic responsive neurostimulation (NeuroPace RNS ® System). The thalamic leads were implanted in the centromedian, pulvinar, mediodorsal, or anterior nucleus depending on clinical characteristics, semiology, and localization testing. Changes in the average power of predefined frequency bands in the interictal thalamic iEEGs were evaluated in ambulatory daily recordings collected postimplant. RESULTS: Two clusters in frequency characteristics were clearly distinguished by time of day (daytime vs. nighttime). The time series evolution for points in the two clusters was not generally correlated, and sometimes diverged. Clusters were more prominent on some channels than others, even between adjacent electrode contacts on the same leads, perhaps reflecting the anatomic location. CONCLUSIONS: These results suggest that thalamic iEEG data can potentially be used to identify wake/sleep states electrographically without traditional sleep studies. This could enable state-dependent neuromodulation therapy. The observed changes in sleep/wake clusters over time could represent neuromodulation-driven changes in thalamocortical networks and warrant further investigation.
Linking New Onset Epilepsy Risk-of-Relapse to EEG Connectivity and Microstates.
Ménétré E, Stancu P, Jekic S … +3 more , De Massias De Bonne J, Seeck M, Gallotto S
J Clin Neurophysiol · 2026 Jan · PMID 41481518 · Publisher ↗
PURPOSE: Antiseizure medication is the first-line treatment for new-onset-epilepsy, leading to seizure control in 70% to 80% of patients. An early identification of an appropriate treatment is extremely important to avoi...
PURPOSE: Antiseizure medication is the first-line treatment for new-onset-epilepsy, leading to seizure control in 70% to 80% of patients. An early identification of an appropriate treatment is extremely important to avoid seizure relapses, and biomarkers for relapse risk are needed to avoid any delays. The authors investigated electroencephalography (EEG)-based brain connectivity and microstates between patients with new-onset epilepsy who responded to treatment (SZ-FREE) and patients who relapsed (SZ-REL), to link potential differences to treatment response. METHODS: Sixty-two patients with new-onset epilepsy for whom an EEG was performed before treatment initiation, after a first seizure event. The authors computed EEG connectivity for delta, theta, alpha, beta, and gamma frequencies, and microstates. By performing mixed-model analyses, the authors tested connectivity differences across frequency bands and microstate characteristic changes between SZ-FREE and SZ-REL. RESULTS: After treatment, 51 patients remained seizure free while 11 relapsed within 6 months. The authors observed a significant interaction between frequency bands and groups (P < 0.001). Post hoc tests showed delta (P = 0.006) and theta (P = 0.012) decreases, and alpha increases (P < 0.001) for patients with SZ-REL compared with patients with SZ-FREE. Microstate C had a significantly higher global explained variance for patients with SZ-REL than patients with SZ-FREE (P = 0.021), while microstates A occurred more frequently in SZ-REL (P = 0.031). CONCLUSIONS: EEG connectivity and microstates in the first EEG within 24 hours after the initial seizure hold valuable information related to the drug responsiveness in patients with new-onset epilepsy. SIGNIFICANCE: EEG connectivity and microstates are potential markers of treatment response.
The Predictive Power of Intraoperative EEG and Clinical Characteristics for Postoperative Delirium Following Cardiac Surgery.
Wiredu K, Sun H, Boncompte G … +3 more , Westover MB, Pedemonte JC, Akeju O
J Clin Neurophysiol · 2026 Jan · PMID 41481100 · Publisher ↗
INTRODUCTION: Postoperative delirium is common and associated with poor postoperative outcomes. However, the predictive power of intraoperative electroencephalogram (EEG) features for postoperative delirium has not yet b...
INTRODUCTION: Postoperative delirium is common and associated with poor postoperative outcomes. However, the predictive power of intraoperative electroencephalogram (EEG) features for postoperative delirium has not yet been well studied. METHODS: Intraoperative EEG data from 261 patients who underwent major cardiac surgery were analyzed. Cases were identified using the Confusion Assessment Method. Predictive analytics for delirium outcome were performed using (1) only clinical data, (2) only EEG data, and (3) a combined list of important features from the first two stages. RESULTS: Eleven percentage of participants experienced postoperative delirium. The patients were generally older and had lower physical and cognitive function. EEG models were found to be highly specific but less sensitive in identifying delirium cases. The combined EEG-clinical model performed comparably to the clinical-only model (AUC = 80%) but outperformed the EEG-only model (AUC = 56%). After adjusting for clinical covariates, only interhemispheric mutual information remained significantly associated with delirium (OR = 2.29, p = 0.03), with a positive correlation with delirium severity (ρ = 0.18, P ≤ 0.01). CONCLUSIONS: This study enhances our understanding of delirium neurophysiology by emphasizing the role of intraoperative EEG as a marker of brain vulnerability. Although EEG may not constitute a standalone biomarker of delirium, it holds promise for delirium risk stratification.
American Clinical Neurophysiology Society Technical Standards for Performing Intraoperative Electrocorticography.
Schuele S, Husain A, Tatum W … +11 more , Gavvala J, Selioutski O, Sinha SR, Inati S, Jacobs J, Gloss D, Alkawadri R, Nordli D, Templer J, Keller C, Nuwer M
J Clin Neurophysiol · 2026 Feb · PMID 41461049 · Publisher ↗
PURPOSE: These consensus guidelines by the American Clinical Neurophysiology Society (ACNS) describe best practices for performing intraoperative Electrocorticography (ioECoG) using subdural or depth electrodes for adult...
PURPOSE: These consensus guidelines by the American Clinical Neurophysiology Society (ACNS) describe best practices for performing intraoperative Electrocorticography (ioECoG) using subdural or depth electrodes for adult and pediatric population. METHODS: A group of ACNS members was convened to develop technical standards for performing ioECoG. PubMed searches were performed to identify pertinent peer-reviewed literature. Sections were assigned to individual authors based on expertise. Consensus was achieved during subsequent group discussions to develop evidence-based recommendations to the extent possible. RECOMMENDATIONS: Communication between the neurosurgical and the neurophysiology teams is essential in verifying and documenting the location of the contacts. Most authors recommend ioECoG recordings of at least 5 and up to 30 minutes in duration to allow for sufficient observation of interictal activity. The anesthesia should be adjusted to allow continuous EEG activity and to minimize the effect on the ioECoG recording during general anesthesia or awake surgery. The surgical procedure and technical report should separate ioECoG recordings to define the irritative zone from ioECoG findings during functional mapping. The neurophysiology physician's physical presence in the operating room is required in the definition of the services. CONCLUSION: These consensus guidelines by the ACNS describe best practices for performing intraoperative ECoG based on published literature and expert consensus.
Ictal Bruxism in Temporal Lobe Epilepsy: Intracranial EEG Connectivity Study.
Tang LW, Sindhu U, Gonzalez-Martinez J … +1 more , Aung T
J Clin Neurophysiol · 2026 Apr · PMID 41432429 · Publisher ↗
Ictal bruxism is a rare motor manifestation in temporal lobe epilepsy with unclear network underpinnings. We report the first case demonstrating SEEG-guided network characterization of ictal bruxism in a 55-year-old man...
Ictal bruxism is a rare motor manifestation in temporal lobe epilepsy with unclear network underpinnings. We report the first case demonstrating SEEG-guided network characterization of ictal bruxism in a 55-year-old man with drug-resistant temporal lobe epilepsy who continued to experience stereotyped seizures with rhythmic teeth grinding after a failed anterior temporal lobectomy. SEEG recorded one spontaneous and two stimulation-induced seizures sampling from the superior temporal gyrus, anterior ventral insula (aVInsula), and nine additional regions of interest. Recordings identified seizures originating from the superior temporal gyrus with early propagation to the anterior insulo-opercular regions at bruxism onset. Direct cortical stimulation of both superior temporal gyrus and aVInsula reproduced seizures and bruxism, confirming causal network associations. Time-frequency and coherence analyses demonstrated significant increases in beta and gamma band synchrony between the superior temporal gyrus /AVINSULA and opercular regions, particularly the pars opercularis and frontoparietal operculum, aligning with bruxism onset across all three seizures. Notably, bruxism occurred in the absence of ipsilateral mesial temporal structures, setting it apart from other oro-alimentary automatisms, such as lip smacking, that exhibit theta-predominant coherence within mesial temporal networks. This case highlights ictal bruxism as a network-level phenomenon in temporal lobe epilepsy that warrants classification distinct from typical oro-alimentary automatisms to optimize seizure localization and surgical outcomes.
Unsatisfactory Accuracy and Inconsistent Inter-Rater Reliability Among Electroencephalographers in Identifying Epileptic Spasms.
Wang W, Wan L, Chen J … +12 more , Zhao Y, Wang Z, Fan Y, Lu G, Wang H, Liu T, Cheng W, Xu Y, Zhang Y, Zhang B, Fu L, Yang G
J Clin Neurophysiol · 2025 Dec · PMID 41432425 · Publisher ↗
PURPOSE: It is widely believed that electroencephalographers can identify epileptic spasms (ES) accurately. However, additional research is needed to verify this assumption, especially because some ES can be subtle, invo...
PURPOSE: It is widely believed that electroencephalographers can identify epileptic spasms (ES) accurately. However, additional research is needed to verify this assumption, especially because some ES can be subtle, involving only facial movements, such as eye rolling. METHODS: The EEG data of 22 patients diagnosed with ES (whether or not it is diagnosed as infantile epileptic spasm syndrome) were evaluated by 6 senior electroencephalographers. The content included judgments of the presence or absence of ES throughout the entire examination process for each patient and in segmented pages every 4 seconds and the consistency among electroencephalographers. The inter-rater reliability (IRR) was assessed using the Fleiss kappa statistic. RESULTS: The accuracy of the 6 evaluators for identifying patients with or without ES in the 22-patient data set was 0.727 to 0.90, and the IRR among the 6 raters was moderate (0.45). Moderate IRR was observed among evaluators from tertiary (0.425), and poor IRR was observed among evaluators from nontertiary (0.399) centers. For the 4-second segmented pages, the accuracy for identifying ES in the 22 patients by the 6 evaluators was 0.943 to 1, and the IRR among the 6 evaluators was good agreement (0.63). CONCLUSIONS: Omissions in the identification of ES episodes were noted among different electroencephalographers, and IRR regarding whether a patient experienced an ES or whether a single event constituted an ES was found to be unsatisfactory. Identifying ES remains challenging for even experienced electroencephalographers.
High-Gain Analysis of Postictal sEEG Suppression Identifies Otherwise Invisible Multifrequency Activity, Including Persisting Ictal Discharges.
Karkar KM, Koneru S, Werry-McFarlin A … +5 more , Karkar MC, Wiedner CD, Himali JJ, Papanastassiou A, Szabo CA
J Clin Neurophysiol · 2026 Apr · PMID 41380013 · Publisher ↗
PURPOSE: Recent studies have challenged the assumption that brain activity is absent or only slow postictally, with reports of higher frequency activity. However, there are conflicting reports as to whether such activity...
PURPOSE: Recent studies have challenged the assumption that brain activity is absent or only slow postictally, with reports of higher frequency activity. However, there are conflicting reports as to whether such activity is present under significant postictal suppression. To address this question, we performed a high-gain review combined with spectrographic analysis of postictal stereo-EEG suppression. METHODS: The postictal stereo-EEG of six focal to bilateral tonic-clonic seizures was reviewed both at standard gain (50-100 μV/mm) and at ultra-high gain (2-5 μV/mm). Time-frequency spectrographic analysis was performed of one channel in the seizure onset zone during the periictal period. Power of the gamma frequency band was quantified in the first 15 seconds postictally and compared with a preictal baseline. RESULTS: (1) Review at ultra-high gain identified an otherwise invisible evolving mixed-frequency background including high-frequency oscillatory activity, continuing ictal activity in one seizure, and early sharp activity (83.33%). (2) Activity was present despite significant suppression (18.46 μV in the seizure onset zone channel). (3) Time-frequency spectrogram revealed a steep drop of EEG power postictally, including gamma power, yet power was not completely absent. CONCLUSIONS: (1) Although the stereo-EEG appeared suppressed postictally, the combination of direct review at ultra-high gain and spectrographic analysis identified otherwise invisible low-power activity. (2) We found intermittent high-frequency oscillatory activity, early postictal sharp activity, as well as the first report of persistent ictal discharges under apparent suppression. (3) Unmasking this activity could help explain postictal seizure-like behaviors and would challenge how the onset of the postictal state is declared.
Video-Polysomnography in Peripheral Nerve Hyperexcitability: Clues to Morvan Syndrome in Two Patients and Literature Review.
Cakar MM, Maharramov E, Gul AC … +3 more , Yildiz FG, Tan E, Tezer FI
J Clin Neurophysiol · 2026 Feb · PMID 41348524 · Publisher ↗
Peripheral nerve hyperexcitability syndromes are characterized by spontaneous motor discharges, fasciculations, and cramps. Morvan syndrome differs from Isaacs syndrome by its central nervous system involvement, autonomi...
Peripheral nerve hyperexcitability syndromes are characterized by spontaneous motor discharges, fasciculations, and cramps. Morvan syndrome differs from Isaacs syndrome by its central nervous system involvement, autonomic dysfunction, and profound sleep disruption, often presenting as agrypnia excitata. We report two seropositive patients with cramps, fasciculations, insomnia, and autonomic dysfunction but without neuropsychiatric features. Case 1, a 49-year-old man, had LGI1 antibodies and presented with insomnia and autonomic symptoms. Video-polysomnography revealed severe insomnia with absent N3/REM sleep, reduced spindles and K-complexes, and oneiric stupor behaviors. Case 2, a 25-year-old woman, had LGI1 and CASPR2 antibodies, neuropathic pain, and fasciculations. Video-polysomnography demonstrated REM sleep without atonia, rapid N1-to-REM transitions, and microstructural abnormalities of N2 sleep. Tumor screening was negative in both; both improved with immunotherapy. A literature review confirms that video-polysomnography consistently reveals central involvement in Morvan syndrome, characterized by loss of sleep spindles, K-complexes, and pathological REM features, while Isaacs syndrome preserves normal sleep structure. Video-polysomnography is therefore an essential tool to detect subclinical central nervous system dysfunction in Morvan syndrome, especially when neuropsychiatric symptoms are absent, and helps distinguish it from Isaacs syndrome.
Resection After Responsive Neurostimulation for Bilateral Mesial Temporal Epilepsy: Why Continuing Neurostimulation After Resection Matters.
de Leon Ernst L, Raslan AM, Zimmerman C … +2 more , Kellogg M, Smith WB
J Clin Neurophysiol · 2026 Mar · PMID 41251468 · Publisher ↗
PURPOSE: Prior research has suggested that select patients with refractory bilateral mesial temporal lobe epilepsy (MTLE) treated with responsive neurostimulation (RNS) may benefit from eventual resection of the more act...
PURPOSE: Prior research has suggested that select patients with refractory bilateral mesial temporal lobe epilepsy (MTLE) treated with responsive neurostimulation (RNS) may benefit from eventual resection of the more active side. However, there is little guidance regarding the role for continuing RNS therapy after unilateral resection. Our series aims to help define the utility of continued RNS therapy after resection and offer guiding principles for neurostimulation in this context. METHODS: Retrospective chart review was performed for patients who underwent RNS implant surgery for bilateral MTLE at our institution between the years 2015-2024. RESULTS: Five patients with RNS treating bilateral hippocampi ultimately underwent selective mesial temporal lobe resection on the primary side. After resection, 4/5 became seizure-free immediately; patient 4 had a 70% seizure reduction, with reemergence of seizures on the less active side. After reprogramming RNS to increase total number of daily stimulations, patient 4 became seizure-free. All patients continued RNS therapy after resection with the ipsilateral electrode used for monitoring, while the contralateral electrode monitored and delivered stimulation. Two patients had transient interruptions of RNS stimulation after resection associated with seizure relapse, followed by return to seizure freedom once stimulation was restored. CONCLUSIONS: This series suggests that (1) unilateral remission in patients with bilateral MTLE being treated with RNS may be stimulation dependent; thus, stimulation should continue after unilateral resection; (2) unilateral seizure remission may depend on a particular threshold of number of stimulations per day.
Diagnostic Utility of 2L-IO Latency Difference in Carpal Tunnel Syndrome: An Electrophysiologic Perspective.
Duman İlki C, Özaydın Aksun Z, Şener HÖ
J Clin Neurophysiol · 2026 Jul · PMID 41248438 · Publisher ↗
PURPOSE: This study aimed to evaluate the diagnostic value of the second lumbrical-interosseous distal motor latency (2L-IO distal motor latency [DML]) difference in the diagnosis of carpal tunnel syndrome, and to assess...
PURPOSE: This study aimed to evaluate the diagnostic value of the second lumbrical-interosseous distal motor latency (2L-IO distal motor latency [DML]) difference in the diagnosis of carpal tunnel syndrome, and to assess its utility across different stages of the disease. METHODS: A total of 145 carpal tunnel syndrome-affected hands from 89 patients and 52 hands from 31 healthy volunteers were evaluated between January and August 2023. In addition to standard electrophysiologic tests, the DML difference between the 2L and interosseous muscles was recorded. Carpal tunnel syndrome severity was classified according to the Bland scale. The diagnostic sensitivity and specificity of the 2L-IO DML difference were analyzed using receiver operating characteristic analysis. RESULTS: The 2L-IO DML difference was significantly prolonged in the carpal tunnel syndrome group compared with healthy controls (1.85 ± 1.41 ms vs. 0.25 ± 0.28 ms; P < 0.001). With a cutoff value of 0.45 ms, the sensitivity and specificity of the method were calculated as 98.6 and 98.1%, respectively. Although the diagnostic accuracy of conventional tests was 84%, it increased to 98% with the 2L-IO DML difference. Diagnosis was achieved in 85% of early stage (Grade 0-1) cases and in 90% of advanced cases in which the abductor pollicis brevis response was absent. CONCLUSIONS: The 2L-IO DML difference offers high diagnostic value in carpal tunnel syndrome, serving as a complementary test in early stages and a decisive tool in advanced stages. Preferentially recording from the 2L muscle instead of the abductor pollicis brevis may facilitate electrophysiologic evaluation, especially in challenging cases.
Role and Functions of the Human Orbitofrontal Cortex.
Robin A, Bastin J
J Clin Neurophysiol · 2025 Nov · PMID 41186438 · Publisher ↗
The orbitofrontal cortex (OFC) plays a pivotal role in integrating sensory, emotional, and cognitive signals to support flexible, goal-directed behavior. This review synthesizes converging evidence from lesion studies, n...
The orbitofrontal cortex (OFC) plays a pivotal role in integrating sensory, emotional, and cognitive signals to support flexible, goal-directed behavior. This review synthesizes converging evidence from lesion studies, neuroimaging, intracranial recordings and stimulations to elucidate the OFC's contribution to emotional regulation, social behavior, and value-based decision making. Lesions in the OFC are associated with affective disturbances, social disinhibition, and impaired behavioral adaptation to feedback. The OFC evaluates the hedonic valence of stimuli across sensory modalities-visual, gustatory, olfactory, somatosensory, and auditory-thereby contributing to subjective affective experience. Intracranial and neuroimaging data further underscore the OFC's involvement in processing emotional facial expressions, tactile pleasure, and social cues such as attractiveness and vocal identity. Stimulation studies provide causal evidence for the OFC's role in modulating emotional perception and mood. Structural and functional alterations of the OFC are consistently observed across multiple neuropsychiatric conditions, including major depressive disorder, obsessive-compulsive disorder, borderline personality disorder, and addiction. These abnormalities manifest as impaired reward processing, increased impulsivity, and affective dysregulation, and may be ameliorated by targeted neuromodulatory interventions such as deep brain stimulation and repetitive transcranial magnetic stimulation. Collectively, findings highlight the OFC as a central hub for affective-cognitive integration and as a promising target for therapeutic modulation in psychiatric disorders.
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