Journal Of Clinical Neurophysiology[JOURNAL]
Sun
200 papers
Epileptiform Discharges Recorded as Monopoles and Dipoles in the EEG: A Practical Approach to Differentiate Tangential and Radial Generators Using Electrode Position Versus Voltage Graphs.
Garcia-Losarcos N, Hongxuyang Y, Thyagaraj S … +2 more , Hampson JP, Lüders H
J Clin Neurophysiol · 2024 Sep · PMID 39186586 · Publisher ↗
Differentiating dipoles (tangential generators) from monopoles (radial generators) in routine EEG reading can be difficult. The polarity of sharp waves seen on surface EEG will change depending on the generator being loc...
Differentiating dipoles (tangential generators) from monopoles (radial generators) in routine EEG reading can be difficult. The polarity of sharp waves seen on surface EEG will change depending on the generator being located at the wall of the sulcus versus the crown of a gyrus. In this article, the authors introduce visual rules that may be used to determine polarity and estimate the localization of potentials during analysis of the EEG. They also review a practical approach to differentiate monopoles (radial generators) from dipoles (tangential dipoles) in the surface EEG using "electrode position versus voltage graphs." Finally, the authors illustrate examples of dipoles and monopoles with focal spikes located in the following locations: (1) bipolar spikes located in the anterior bank of the central sulcus, (2) bipolar spikes located in the posterior bank of the central sulcus, (3) monopolar spikes located in the crown of the precentral gyrus, (4) bipolar spikes with a vertically oriented dipole originated within the temporal (inferior) bank of the Sylvian fissure, and (5) monopolar spikes located in the convexity of a temporal gyrus. In summary, this article discusses electrographic features of spikes localized in various fissures and gyri and provides practical rules that permit the identification and location of dipoles and monopoles in standard scalp EEG recordings.
Cyclic Alternating EEG Patterns: From Sleep to Encephalopathy.
Misirocchi F, Mutti C, Hirsch LJ … +2 more , Parrino L, Florindo I
J Clin Neurophysiol · 2024 Sep · PMID 39186585 · Publisher ↗
In the 2021 version of the Standardized Critical Care EEG Terminology, the American Clinical Neurophysiology Society introduced new definitions, including for the cyclic alternating pattern of encephalopathy (CAPE). CAPE...
In the 2021 version of the Standardized Critical Care EEG Terminology, the American Clinical Neurophysiology Society introduced new definitions, including for the cyclic alternating pattern of encephalopathy (CAPE). CAPE refers to changes in background EEG activity, with two patterns alternating spontaneously in a regular manner. CAPE shares remarkable similarities with the cyclic alternating pattern, a natural EEG phenomenon occurring in normal non-rapid eye movement sleep, considered the main electrophysiological biomarker of sleep instability. This review explores similarities and differences between cyclic alternating pattern and CAPE and, leveraging the existing expertise on cyclic alternating pattern, aims to extend knowledge on CAPE. A standardized assessment of CAPE features is key to ascertain its prevalence and clinical significance among critically ill patients and to encompass the impact of confounding factors such as anesthetic and sedative agents. Although the preservation of non-rapid eye movement sleep-related elements has a well-known prognostic value in the critical care setting, the clinical importance of cyclic oscillating patterns and the prognostic significance of CAPE remain to be elucidated.
Sensor-Head Distance and Signal Strength in Whole-Head Magnetoencephalography: Report of 996 Patients With Epilepsy.
Tanaka N, Ahlfors SP, Stufflebeam SM
J Clin Neurophysiol · 2025 Mar · PMID 39177533 · Publisher ↗
PURPOSE: Although the sensor-to-head distance is theoretically known to affect the signal strength in magnetoencephalography (MEG), these values have not been reported for a whole-head MEG system in a large population. W...
PURPOSE: Although the sensor-to-head distance is theoretically known to affect the signal strength in magnetoencephalography (MEG), these values have not been reported for a whole-head MEG system in a large population. We measured the distance and signal strength in 996 patients with epilepsy. METHODS: The MEG sensor array consisted of 102 measurement sites, each of which had two gradiometers and one magnetometer. The sensor-head distance was defined as the minimum distance between each site and a set of digitized scalp points. For the signal strength, we calculated the root-mean-square of the signal values in each sensor over a recording of 4 minutes. For analyses at the individual and sensor levels, these values were averaged over the sensors and patients, respectively. We evaluated the correlation between distance and signal strength at both individual and sensor levels. At the sensor level, we investigated regional differences in these measures. RESULTS: The individual-level analysis showed only a weak negative correlation between the sensor-head distance and the signal strength. The sensor-level analysis demonstrated a considerably negative correlation for both gradiometers and magnetometers. The sensor-head distances showed no significant differences between the regions, whereas the signal strength was higher in the temporal and occipital sensors than in the frontal and parietal sensors. CONCLUSIONS: Sensor-head distance was not a definitive factor for determining the magnitude of MEG signals in individuals. Yet, the distance is important for the signal strength at a sensor level. Regional differences in signal strength may need to be considered in the analysis and interpretation of MEG.
Transcranial Direct Current Stimulation in Children With Anisometropic Amblyopia.
El Salmawy DA, Elhadidy R, Shuaib A … +2 more , Ashraf Mahmoud E, Nada MM
J Clin Neurophysiol · 2025 May · PMID 39175115 · Publisher ↗
BACKGROUND: Amblyopia is defined clinically as a difference in best-corrected visual acuity of two or more lines of acuity (0.2 logMAR) between the eyes. Transcranial direct current stimulation (tDCS) is a noninvasive br...
BACKGROUND: Amblyopia is defined clinically as a difference in best-corrected visual acuity of two or more lines of acuity (0.2 logMAR) between the eyes. Transcranial direct current stimulation (tDCS) is a noninvasive brain stimulation technique that can transiently alter the excitability of targeted brain areas in a polarity-specific manner. PURPOSE: To detect the effect of tDCS on anisometropic amblyopia. METHODS: This is a randomized controlled trial conducted on 78 patients with anisometropic amblyopia from 4.5 to 12 years of age. All patients presented with monocular amblyopia. They were divided into three groups; each group received five sessions of tDCS (anodal tDCS, cathodal tDCS, and sham tDCS). The active electrode was placed over occipital midline and the reference over central midline. Pattern visual-evoked potentials and contrast sensitivity tests were conducted before, immediately after, and 1 week after tDCS. RESULTS: The amplitude of P100 was significantly decreased immediately after and 1 week after cathodal tDCS. The latency of P100 immediately after and 1 week after anodal tDCS was significantly decreased and increased significantly after cathodal tDCS. The amplitude of P100 and maximum and minimum contrast sensitivities were significantly increased immediately after and 1 week after anodal tDCS, and maximum contrast sensitivity was significantly decreased immediately after cathodal tDCS. CONCLUSION: Anodal tDCS is a promising noninvasive modality for improvement of anisometropic amblyopia.
Intraoperative Neuromonitoring for the Lower-Extremity Region Using Motor-Evoked Potential With Direct Cortical Stimulation in Brain Tumor Surgeries.
Takatani T, Matsuda R, Hayashi H … +8 more , Maeoka R, Nakase K, Morisaki Y, Yokoyama S, Takeshima Y, Nakagawa I, Momoyama Y, Kawaguchi M
J Clin Neurophysiol · 2025 Mar · PMID 39090797 · Publisher ↗
PURPOSE: To evaluate the motor function of the lower extremity (LE), we used direct cortical stimulation motor-evoked potential (D-MEP) monitoring with a single six-contact subdural strip electrode placed in the interhem...
PURPOSE: To evaluate the motor function of the lower extremity (LE), we used direct cortical stimulation motor-evoked potential (D-MEP) monitoring with a single six-contact subdural strip electrode placed in the interhemispheric fissure. METHODS: Intraoperative neuromonitoring using D-MEPs in the LE was performed in 18 cases (16 patients) for brain tumor surgery from December 2018 to April 2023 with a follow-up period of at least 3 months. After dural opening, a single six-contact subdural strip electrode was placed inside the interhemispheric fissure. To identify the central sulcus, phase reversal was recorded using somatosensory evoked potentials. Next, direct cortical stimulation was applied to the primary motor cortex. The baseline waveform was defined as a reproducible waveform of 30 µV or higher, and a significant decrease of ≥50% in the amplitude resulted in a warning during surgery. RESULTS: The success rate of central sulcus identification in the LE was 66.7% (12/18 cases). Direct cortical stimulation motor-evoked potential monitoring could record stable contralateral motor-evoked potentials of the tibialis anterior, gastrocnemius, and abductor hallucis in 16 of 18 cases (88.9%). The mean intensity of stimulation for D-MEPs was 20.5 ± 9.9 mA, and the 16 cases showed no significant reduction in amplitude. Seventeen cases showed no deterioration of motor function of the LE at 1 and 3 months postoperatively. In the remaining case with unsuccessful D-MEP, paralysis of the LE worsened at 1 and 3 months postoperatively. CONCLUSIONS: The placement of electrodes in the interhemispheric fissure on the primary motor cortex of the LE enabled motor-function monitoring in the LE with D-MEPs, suggesting that D-MEP-based monitoring may be a reliable approach.
Agreement and Consistency of Absolute and Relative Corticospinal Stimulus-Response Curves for Upper, Lower, and Axial Musculature in Healthy Adults.
Hougland JR, Proessl F, Meglino N … +5 more , Canino MC, Sterczala AJ, Connaboy C, Nindl BC, Flanagan SD
J Clin Neurophysiol · 2025 Mar · PMID 39090794 · Publisher ↗
PURPOSE: To assess the agreement and consistency of absolute and relative stimulus-response curve (SRC) parameter estimates for upper extremity, lower extremity, and axial muscles. METHODS: Thirty (15 W, age: 27.0 ± 6.3...
PURPOSE: To assess the agreement and consistency of absolute and relative stimulus-response curve (SRC) parameter estimates for upper extremity, lower extremity, and axial muscles. METHODS: Thirty (15 W, age: 27.0 ± 6.3 y, height: 171.9 ± 8.9 cm, weight: 80.2 ± 19.3 kg) healthy adults completed absolute (5% to 100% stimulator output) and relative (65% to 160% motor threshold) SRCs of the first dorsal interosseous, vastus lateralis, and rectus abdominis during submaximal isometric contractions. Mean motor-evoked potential amplitudes were fit with nonlinear regression to derive MEP max , V 50 , and slope. Absolute agreement and consistency were assessed with ICCs, Cronbachs alphas, and Bland-Altman plots. Independent t -tests were used to examine differences in motor threshold, physical activity, strength, and muscle activity among participants with valid and invalid SRC parameters. RESULTS: Absolute and relative SRCs displayed good agreement and consistency for MEP max and V 50 but not slope. Motor thresholds were lower among participants with valid absolute SRCs for the rectus abdominis and vastus lateralis. Motor threshold, physical activity, strength, and muscle activity did not differ among those with valid and invalid parameters for all relative SRCs and absolute SRCs for the first dorsal interosseous. CONCLUSIONS: Absolute and relative SRCs produce similar MEP max and V 50 estimates in the first dorsal interosseous, vastus lateralis, and rectus abdominis. The validity of absolute and relative SRC results may differ depending on individual characteristics and tested muscles.
Visual Electroencephalography Assessment in the Diagnosis and Prognosis of Cognitive Disorders.
Michels DM, van Marum S, Arends S … +3 more , Tavy DLJ, Wirtz PW, de Bruijn BSFTM
J Clin Neurophysiol · 2025 Mar · PMID 39051913 · Full text
PURPOSE: Electroencephalography (EEG) is a noninvasive diagnostic tool that can be of diagnostic value in patients with cognitive disorders. In recent years, increasing emphasis has been on quantitative EEG analysis, whi...
PURPOSE: Electroencephalography (EEG) is a noninvasive diagnostic tool that can be of diagnostic value in patients with cognitive disorders. In recent years, increasing emphasis has been on quantitative EEG analysis, which is not easily accessible in clinical practice. The aim of this study was to assess the diagnostic and prognostic value of visual EEG assessment to distinguish different causes of cognitive disorders. METHODS: Patients with cognitive disorders from a specialized memory clinic cohort underwent routine workup including EEG, neuropsychological testing and brain imaging. Electroencephalography parameters including posterior dominant rhythm, background activity, and response to photic stimulation (intermittent photic stimulation) were visually scored. Final diagnosis was made by an expert panel. RESULTS: A total of 501 patients were included and underwent full diagnostic workup. One hundred eighty-three patients had dementia (111 Alzheimer disease, 30 vascular dementia, 15 frontotemporal dementia, and 9 dementia with Lewy bodies), 66 patients were classified as mild cognitive impairment, and in 176, no neurologic diagnosis was made. Electroencephalography was abnormal in 60% to 90% of patients with mild cognitive impairment and dementia, most profoundly in dementia with Lewy bodies and Alzheimer disease, while frontotemporal dementia had normal EEG relatively often. Only 30% of those without neurologic diagnosis had EEG abnormalities, mainly a diminished intermittent photic stimulation response. Odds ratio of conversion to dementia was 6.1 [1.5-24.7] for patients with mild cognitive impairment with abnormal background activity, compared with those with normal EEG. CONCLUSIONS: Visual EEG assessment has diagnostic and prognostic value in clinical practice to distinguish patients with memory complaints without underlying neurologic disorder from patients with mild cognitive impairment or dementia.
The Fingerprint of Scalp-EEG in Drug-Resistant Frontal Lobe Epilepsies.
Kalss G, Pelliccia V, Zimmermann G … +2 more , Trinka E, Tassi L
J Clin Neurophysiol · 2025 Mar · PMID 39042052 · Full text
PURPOSE: Scalp-EEG incompletely covers the frontal lobe cortex. Underrepresentation of frontobasal or frontomesial structures, fast ictal spreading, and false lateralization impede scalp-EEG interpretation. Hence, we inv...
PURPOSE: Scalp-EEG incompletely covers the frontal lobe cortex. Underrepresentation of frontobasal or frontomesial structures, fast ictal spreading, and false lateralization impede scalp-EEG interpretation. Hence, we investigated the significance of scalp-EEG in the presurgical workup of frontal lobe epilepsy. METHODS: Using descriptive statistical methods and Pearson chi-squared test for group comparisons, we retrospectively investigated postsurgical outcome, interictal epileptiform discharges (iiEDs), and electrographic seizure patterns on scalp-EEG in 81 consecutive patients undergoing resective epilepsy surgery within the margins of the frontal lobe. RESULTS: Postoperatively, patients with frontopolar iiEDs ( n = 7) or concordant frontopolar iiED focus and seizure-onset ( n = 2) were seizure free ( n = 7/7, Engel Ia). MRI-positive patients with frontopolar iiEDs or frontopolar seizure-onset ( n = 1/8 Engel Id, n = 7/8 Engel Ia) underwent surgery without stereo-EEG. Thirteen of 16 patients with frontolateral ( n = 8/10, Engel Ia), or left frontobasal ( n = 5/6, Engel Ia) seizure-onset undergoing further stereo-EEG, were seizure-free postoperatively. Seizure-onset prevalent over one electrode ( n = 37/44 Engel I, p = 0.02), fast activity (FA)/flattening at seizure-onset ( n = 29/33 Engel I, p = 0.02), FA/flattening during the seizure ( n = 38/46 Engel I, p = 0.05), or focal rhythmic sharp-/spike-/polyspike-and-slow waves during the seizure ( n = 24/31, Engel Ia, p = 0.05) were favorable prognostic markers. Interictal polyspike waves ( p = 0.006 for Engel Ia) and interictal paroxysmal FA ( p = 0.02 for Engel I) were unfavorable prognostic markers. CONCLUSIONS: Frontopolar scalp-EEG findings serve as biomarkers for predicting favorable surgical outcome in lesional frontal lobe epilepsy. Consequently, careful analysis of scalp-EEG assists in bypassing stereo-EEG in these patients.
Resolving a "W-Shaped" P100 Waveform: Is It Normal or Abnormal?
Martin-Gonzalez M, Husain AM
J Clin Neurophysiol · 2025 Jan · PMID 38980726 · Publisher ↗
Pattern-reversal visual evoked potentials are used to assess the visual pathways. The main waveform of interest is the P100, which is best recorded with electrodes over the mid-occipital region. Most often, the P100 wave...
Pattern-reversal visual evoked potentials are used to assess the visual pathways. The main waveform of interest is the P100, which is best recorded with electrodes over the mid-occipital region. Most often, the P100 waveform has negative-positive-negative components. Occasionally, it is "W-shaped," with positive-negative-positive components. Although most often a W-shaped P100 waveform indicates an abnormality in the visual pathway, occasionally, it can be normal. A case is presented in which a W-shaped P100 waveform is seen after monocular full-field stimulation of both eyes with 30' checks. To resolve this finding, the pattern-reversal visual evoked potentials is repeated with 60' and 15' checks. With 15' checks a single typical single-peak P100 waveform is seen with normal latency. Evaluation of a W-shaped P100 waveform should involve analysis of various montages, stimulation with different check sizes, and hemifield stimulation to confirm whether the W-shaped waveform is normal or abnormal.
Comparison of Bilateral Versus Unilateral 5 Hz or 1 Hz Repetitive Transcranial Magnetic Stimulation in Subacute Stroke: Assessment of Motor Function in a Randomized Controlled Study.
Abdelkader AA, Afifi LM, Maher EA … +2 more , Atteya AA, El Salmawy DA
J Clin Neurophysiol · 2024 Jul · PMID 38935659 · Publisher ↗
PURPOSE: Repetitive transcranial magnetic stimulation (rTMS) can enhance brain plasticity after stroke. At low frequencies, rTMS has an inhibitory effect, whereas at high frequencies, it has an excitatory effect. Combini...
PURPOSE: Repetitive transcranial magnetic stimulation (rTMS) can enhance brain plasticity after stroke. At low frequencies, rTMS has an inhibitory effect, whereas at high frequencies, it has an excitatory effect. Combining both frequencies in bilateral stimulation is a new rTMS protocol under investigation, especially in the subacute stage. METHODS: Fifty-five patients with subacute stroke were divided into four groups according to the rTMS protocol delivered: bilateral, inhibitory, excitatory, and control groups. All groups received concomitant task-oriented physiotherapy. Pretreatment to posttreatment assessment was performed twice, immediately after sessions and 1 month later. Volitional motor control was evaluated by Fugl-Meyer and Wolf motor function tests, and for spasticity, the Ashworth scale was used. RESULTS: All groups showed significant improvement. Bilateral, inhibitory, and excitatory groups showed same efficacy, but the bilateral protocol was superior in spasticity. No correlations were found between improvement and stroke duration and site except for spasticity. CONCLUSIONS: Bilateral rTMS shows a comparable effect to inhibitory and excitatory rTMS in improving motor disability in subacute stroke. However, it is superior for spasticity.
Beyond Stereo-EEG: Is It Worth Combining Stereo-EEG With Other Diagnostic Methods?
Jacobs J, Klotz KA, Pizzo F … +1 more , Federico P
J Clin Neurophysiol · 2024 Jul · PMID 38935658 · Publisher ↗
Stereo-EEG is a widely used method to improve the diagnostic precision of presurgical workup in patients with refractory epilepsy. Its ability to detect epileptic activity and identify epileptic networks largely depends...
Stereo-EEG is a widely used method to improve the diagnostic precision of presurgical workup in patients with refractory epilepsy. Its ability to detect epileptic activity and identify epileptic networks largely depends on the chosen implantation strategy. Even in an ideal situation, electrodes record activity generated in <10% of the brain and contacts only record from brain tissue in their immediate proximity. In this article, the authors discuss how recording stereo-EEG simultaneously with other diagnostic methods can improve its diagnostic value in clinical and research settings. It can help overcome the limited spatial coverage of intracranial recording and better understand the sources of epileptic activity. Simultaneous scalp EEG is the most widely available method, often used to understand large epileptic networks, seizure propagation, and EEG activity occurring on the contralateral hemisphere. Simultaneous magnetoencephalography allows for more precise source localization and identification of deep sources outside the stereo-EEG coverage. Finally, simultaneous functional MRI can highlight metabolic changes following epileptic activity and help understand the widespread network changes associated with interictal activity. This overview highlights advantages and methodological challenges for all these methods. Clinical use and research applications are presented for each approach.
Clinical Utility of Sleep Recordings During Presurgical Epilepsy Evaluation With Stereo-Electroencephalography: A Systematic Review.
Hannan S, Ho A, Frauscher B
J Clin Neurophysiol · 2024 Jul · PMID 38935657 · Publisher ↗
Although the role of sleep in modulating epileptic activity is well established, many epileptologists overlook the significance of considering sleep during presurgical epilepsy evaluations in cases of drug-resistant epil...
Although the role of sleep in modulating epileptic activity is well established, many epileptologists overlook the significance of considering sleep during presurgical epilepsy evaluations in cases of drug-resistant epilepsy. Here, we conducted a comprehensive literature review from January 2000 to May 2023 using the PubMed electronic database and compiled evidence to highlight the need to revise the current clinical approach. All articles were assessed for eligibility by two independent reviewers. Our aim was to shed light on the clinical value of incorporating sleep monitoring into presurgical evaluations with stereo-electroencephalography. We present the latest developments on the important bidirectional interactions between sleep and various forms of epileptic activity observed in stereo-electroencephalography recordings. Specifically, epileptic activity is modulated by different sleep stages, peaking in non-rapid eye movement sleep, while being suppressed in rapid eye movement sleep. However, this modulation can vary across different brain regions, underlining the need to account for sleep to accurately pinpoint the epileptogenic zone during presurgical assessments. Finally, we offer practical solutions, such as automated sleep scoring algorithms using stereo-electroencephalography data alone, to seamlessly integrate sleep monitoring into routine clinical practice. It is hoped that this review will provide clinicians with a readily accessible roadmap to the latest evidence concerning the clinical utility of sleep monitoring in the context of stereo-electroencephalography and aid the development of therapeutic and diagnostic strategies to improve patient surgical outcomes.
Stereoelectroencephalography of the Deep Brain: Basal Ganglia and Thalami.
Pati S, Agashe S, Kheder A … +6 more , Riley K, Gavvala J, McGovern R, Suresh S, Chaitanya G, Thompson S
J Clin Neurophysiol · 2024 Jul · PMID 38935656 · Publisher ↗
Stereoelectroencephalography (SEEG) has emerged as a transformative tool in epilepsy surgery, shedding light on the complex network dynamics involved in focal epilepsy. This review explores the role of SEEG in elucidatin...
Stereoelectroencephalography (SEEG) has emerged as a transformative tool in epilepsy surgery, shedding light on the complex network dynamics involved in focal epilepsy. This review explores the role of SEEG in elucidating the role of deep brain structures, namely the basal ganglia and thalamus, in epilepsy. SEEG advances understanding of their contribution to seizure generation, propagation, and control by permitting precise and minimally invasive sampling of these brain regions. The basal ganglia, comprising the subthalamic nucleus, globus pallidus, substantia nigra, and striatum, have gained recognition for their involvement in both focal and generalized epilepsy. Electrophysiological recordings reveal hyperexcitability and increased synchrony within these structures, reinforcing their role as critical nodes within the epileptic network. Furthermore, low-frequency and high-frequency stimulation of the basal ganglia have demonstrated potential in modulating epileptogenic networks. Concurrently, the thalamus, a key relay center, has garnered prominence in epilepsy research. Disrupted thalamocortical connectivity in focal epilepsy underscores its significance in seizure maintenance. The thalamic subnuclei, including the anterior nucleus, centromedian, and medial pulvinar, present promising neuromodulatory targets, suggesting pathways for personalized epilepsy therapies. The prospect of multithalamic SEEG and thalamic SEEG stimulation trials has the potential to revolutionize epilepsy management, offering tailored solutions for challenging cases. SEEG's ability to unveil the dynamics of deep brain structures in epilepsy promises enhanced and personalized epilepsy care in our new era of precision medicine. Until deep brain SEEG is accepted as a standard of care, a rigorous informed consent process remains paramount for patients for whom such an exploration is proposed.
Back to Basics: Care of the Stereotactic EEG Implanted Patient.
Alick-Lindstrom S, Venkatesh P, Perven G … +5 more , Wabulya A, Yang QJ, Sirsi D, Podkorytova I, American SEEG Consortium
J Clin Neurophysiol · 2024 Jul · PMID 38935655 · Publisher ↗
PURPOSE: Stereotactic EEG (SEEG) is gaining increasing popularity in the United States. Patients undergoing SEEG have unique challenges, and their needs are different compared with noninvasive cases. We aim to describe t...
PURPOSE: Stereotactic EEG (SEEG) is gaining increasing popularity in the United States. Patients undergoing SEEG have unique challenges, and their needs are different compared with noninvasive cases. We aim to describe the medical, nursing, and other institutional practices of SEEG evaluations among tertiary referral (level IV) epilepsy centers accredited by the National Association of Epilepsy Centers. METHODS: We analyzed data obtained from a Research Electronic Data Capture (REDCap) survey we formulated and distributed to directors of all level IV epilepsy centers listed by the National Association of Epilepsy Center. Most questions were addressed to the adult and pediatric SEEG programs separately. RESULTS: Among 199 epilepsy center directors invited to complete the survey, 90 (45%) responded. Eighty-three centers (92%) reported they perform SEEG evaluations. Of the 83 respondents, 56 perform SEEG in adult and 47 in pediatric patients. Twenty-two centers evaluate both pediatric and adult subjects. The highest concordance of SEEG workflow was in (1) epilepsy monitoring unit stay duration (1-2 weeks, 79% adult and 85% pediatric programs), (2) use of sleep deprivation (94% both adult and pediatric) and photic stimulation (79% adult and 70% pediatric) for seizure activation, (3) performing electrical cortical stimulation at the end of SEEG evaluation after spontaneous seizures are captured (84% adult and 88% pediatric), and (4) daily head-wrap inspection (76% adult and 80% pediatric). Significant intercenter variabilities were noted in the other aspects of SEEG workflow. CONCLUSIONS: Results showed significant variability in SEEG workflow across polled centers. Prospective, multicenter protocols will help the future development and harmonization of optimal practice patterns.
Escaping the Procrustean Bed: A Perspective on Pediatric Stereoelectroencephalography.
Kheder A
J Clin Neurophysiol · 2024 Jul · PMID 38935654 · Publisher ↗
Stereoelectroencephalography is an established, hypothesis-driven method for investigating refractory epilepsy. There are special considerations and some limitations that apply to children who undergo stereoelectroenceph...
Stereoelectroencephalography is an established, hypothesis-driven method for investigating refractory epilepsy. There are special considerations and some limitations that apply to children who undergo stereoelectroencephalography. A key principle in stereoelectroencephalography is taking an individualized approach to investigating refractory epilepsy. A crucial factor for success in a personalized pediatric epilepsy surgery is understanding some of the fundamental and unique aspects of it, including, but not limited to, diverse etiology, epilepsy syndromes, maturation, and age-related characteristics as well as neural plasticity. Such features are reflected in the ontogeny of semiology and electrophysiology. In addition, special considerations are taken into account during cortical stimulation in children. Stereoelectroencephalography can guide a tailored surgical intervention where it is sufficient to render the patient seizure-free but it also lessens collateral damage with a minimum or no functional deficit. Epilepsy surgery outcomes remain stagnant despite advances in noninvasive testing modalities. A stereoelectroencephalography "way of thinking" and guided mentorship may influence outcomes positively.
In Search of a Common Language: The Standardized Electrode Nomenclature for Stereoelectroencephalography Applications.
Chiu MY, Bolton J, Raskin JS … +4 more , Curry DJ, Weiner HL, Pearl PL, Stone S
J Clin Neurophysiol · 2024 Jul · PMID 38935653 · Publisher ↗
PURPOSE: Stereoelectroencephalography (SEEG) is widely performed on individuals with medically refractory epilepsy for whom invasive seizure localization is desired. Despite increasing adoption in many centers across the...
PURPOSE: Stereoelectroencephalography (SEEG) is widely performed on individuals with medically refractory epilepsy for whom invasive seizure localization is desired. Despite increasing adoption in many centers across the world, no standardized electrode naming convention exists, generating confusion among both clinical and research teams. METHODS: We have developed a novel nomenclature, named the Standardized Electrode Nomenclature for SEEG Applications system. Concise, unique, informative, and unambiguous labels provide information about entry point, deep targets, and relationships between electrodes. Inter-rater agreement was evaluated by comparing original electrode names from 10 randomly sampled cases (including 136 electrodes) with those prospectively assigned by four additional blinded raters. RESULTS: The Standardized Electrode Nomenclature for SEEG Application system was prospectively implemented in 40 consecutive patients undergoing SEEG monitoring at our institution, creating unique electrode names in all cases, and facilitating implantation design, SEEG recording and mapping interpretation, and treatment planning among neurosurgeons, neurologists, and neurophysiologists. The inter-rater percent agreement for electrode names among two neurosurgeons, two epilepsy neurologists, and one neurosurgical fellow was 97.5%. CONCLUSIONS: This standardized naming convention, Standardized Electrode Nomenclature for SEEG Application, provides a simple, concise, reproducible, and informative method for specifying the target(s) and relative position of each SEEG electrode in each patient, allowing for successful sharing of information in both the clinical and research settings. General adoption of this nomenclature could pave the way for improved communication and collaboration between institutions.
The United States Stereotactic EEG Survey: Current Practice and Future Opportunities.
Gavvala JR
J Clin Neurophysiol · 2024 Jul · PMID 38935652 · Publisher ↗
PURPOSE: Stereotactic EEG (SEEG) is being increasingly used in the intracranial evaluation of refractory epilepsy in the United States. A 2022 survey of SEEG practices among National Association of Epilepsy Centers terti...
PURPOSE: Stereotactic EEG (SEEG) is being increasingly used in the intracranial evaluation of refractory epilepsy in the United States. A 2022 survey of SEEG practices among National Association of Epilepsy Centers tertiary referral (NAEC level IV) centers found largely similar practices across institutions. However, a few significant differences were noted in technical and patient care practice, and in the level of SEEG background training. In the year since publication, we review the identified challenges facing SEEG practice and suggest specific corrective action. CONCLUSIONS: Stereotactic EEG has rapidly become the principal method for intracranial EEG monitoring in epilepsy surgery centers in the United States. The rate of adoption of SEEG is currently higher than the growth of invasive monitoring overall. Most report similar indications for SEEG, although significant variability exists in personnel expertise and technical and patient care practice. Consensus statements, guidelines, and review of postgraduate training curricula are urgently needed to benchmark SEEG practice and develop appropriate skillsets in the next generation of practitioners in the United States.
The Voyage of SEEG.
Chauvel P
J Clin Neurophysiol · 2024 Jul · PMID 38935651 · Publisher ↗
It took 50 years for stereoelectroencephalography (SEEG) to cross the Atlantic. Conceived and designed before the advent of computers and modern technology, this method turned out to be perfectly suited to brain imaging...
It took 50 years for stereoelectroencephalography (SEEG) to cross the Atlantic. Conceived and designed before the advent of computers and modern technology, this method turned out to be perfectly suited to brain imaging and modern video and electrophysiological tools. It eventually benefited from robotics and signal processing. However, a critical step remains accurate electrode implantation, which is based on individual patients' noninvasive phase I data. A limiting factor, especially in MRI-negative cases, is a thorough perictal and postictal clinical testing for ensuring meaningful electroclinical correlations. Adapted epilepsy monitoring units' architecture and specific technicians and nurses training are required to improve the granularity of information needed to generate valid hypotheses on localization. SEEG interpretation is based on a knowledge base in neural networks, cognitive/behavioral neuroscience, and electrophysiology quite distinct from electroencephalography. Tailored to the needs of focal epilepsy complexity exploration, SEEG does not fit well with simplification. Specific teaching and development of clinical research inside the epilepsy monitoring units will help to flatten the team learning curve and to build knowledge base from shared clinical experience.
The SEEG Wave.
Kalamangalam G, Frauscher B
J Clin Neurophysiol · 2024 Jul · PMID 38935650 · Publisher ↗
Abstract loading — click title to view on PubMed.
A Proposed Stereoelectroencephalography Electrode Nomenclature and Call for Standardization.
Calley CS, Ho W, Babajani-Feremi A … +3 more , Bodden C, Tyler-Kabara E, Clarke DF
J Clin Neurophysiol · 2025 Mar · PMID 38935279 · Publisher ↗
INTRODUCTION: Between 20 and 40% of patients with epilepsy are considered pharmacoresistant. Stereoelectroencephalography (sEEG) is frequently used as an invasive method for localizing seizures in patients with pharmacor...
INTRODUCTION: Between 20 and 40% of patients with epilepsy are considered pharmacoresistant. Stereoelectroencephalography (sEEG) is frequently used as an invasive method for localizing seizures in patients with pharmacoresistant epilepsy who are surgical candidates; however, electrode nomenclature varies widely across institutions. This lack of standardization can have many downstream consequences, including difficulty with intercenter or intracenter interpretation, communication, and reliability. METHODS: The authors propose a novel sEEG nomenclature that is both intuitive and comprehensive. Considerations include clear/precise entry and target anatomical locations, laterality, distinction of superficial and deep structures, functional mapping, and relative labeling of electrodes in close proximity if needed. Special consideration was also given to electrodes approximating radiographically distinct lesions. The accuracy of electrode identification and the use of correct entry-target labels were assessed by neurosurgeons and epileptologists, not directly involved in each case. RESULTS: The authors' nomenclature was used in 41 consecutive sEEG cases (497 electrodes total) within their institution. After reconstruction was complete, the accuracy of electrode identification was 100%, and the correct use of entry-target labels was 98%. The last 30 sEEG cases had 100% correct use of entry-target labels. CONCLUSIONS: The proposed sEEG nomenclature demonstrated both high accuracy in electrode identification and consistent use of entry-target labeling. The authors submit this nomenclature as a model for standardization across epilepsy surgery centers. They intend to improve practicability, ease of use, and specificity of this nomenclature through collaboration with other surgical epilepsy centers.
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