Journal of Clinical Neurophysiology最新文献

Purpose: In patients with epilepsy who achieve seizure freedom, physicians may consider discontinuing antiseizure medications, often using EEG beforehand to guide the decision. This study evaluates the gain in detection of epileptiform discharges (EDs) in 24-hour video EEG (VEEG) monitoring in seizure-free patients.

Methods: The authors identified patients with epilepsy who were seizure free on antiseizure medications and had undergone 24-hour VEEG after an unrevealing routine EEG. The authors evaluated the yield and latency of observed EDs in the VEEG study. The authors compared the rate of ED detection during the first 60 minutes versus later in the recording.

Results: Of the 27 patients, aged 19 to 51 years, 10 (37%) exhibited EDs on 24-hour VEEG. The latency to the first EDs ranged from 52 to 748 minutes, with a median of 164 minutes. Nine of these 10 patients (90%) had their EDs appear only after the first 60 minutes of recording. In other words, prolonging the EEG beyond 1 hour yielded an additional 33.3% of patients with EDs that a 1-hour recording would have missed. Younger age and presence of EDs on a past EEG were predictive of the presence of EDs on VEEG ( P = 0.040 and P = 0.039 respectively).

Conclusions: The results suggest that 24-hour VEEG is more sensitive in detecting EDs than routine EEG in seizure-free patients and thus may be superior in individualized risk assessments for seizure recurrence on potential antiseizure medication discontinuation.

Purpose: The existing literature on the sacral dermatomal evoked potentials (dSEPs) is limited. This study aims to develop stimulating parameters and establish normative values for S2, S3, and S4 sacral dermatomes in healthy adult populations.

Methods: Twenty healthy adult volunteers were enrolled in the study. The study was ethically approved, and written consent for participation was provided. All participants underwent tibial, pudendal, S2, S3, and S4 dSEPs. Stimulating and recorded parameters were established for all evoked potentials. P40 latency, amplitude, and interpeak parameters were calculated for each waveform. A comparison was made between tibial, pudendal somatosensory evoked potentials, and all sacral dSEPs. Normative values were generated for sacral dSEPs based on various height, age, and Body Mass Index (BMI) parameters.

Results: The sacral dSEPs were well tolerated and recorded in all participants. S2 latency was mildly influenced by age and height, while S3 and S4 latencies were unaffected by age or height. BMI does not affect the S2 and S3 latencies but mildly affects the S4 latency. Sacral dSEP latencies were comparable with pudendal SEPS but not with the tibial somatosensory evoked potential.

Conclusions: The S2, S3, and S4 sacral dSEPs can be used as diagnostic tools to evaluate sacral nerve lesions such as cauda equina syndrome and Tarlov cysts, complementary to pudendal and tibial somatosensory evoked potentials.

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 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 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 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 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.

Summary: Responsive neurostimulation and deep brain stimulation have emerged as effective intracranial neuromodulation therapies for drug-resistant epilepsy when surgical resection is not an option. However, programming these devices presents unique challenges in epilepsy. Without immediate feedback and a vast programming space, clinicians are often tasked with fine-tuning device settings without clear, mechanistic guidance and limited clinical time. Recent efforts toward individualized programming have shown promise, including the use of nonstandard parameter sets, target-specific stimulation strategies, and patient-tailored adaptations while avoiding unintended interference with critical functions such as emotional regulation. Emerging research in programming is shifting beyond the one-size-fits-all protocols, incorporating closed-loop biomarkers, integrating multimodal data and predictive modeling that hold promise for improving seizure control and reducing adverse effects. This review synthesizes current evidence on standard and individualized programming approaches for deep brain stimulation and responsive neurostimulation in epilepsy, highlighting practical strategies, clinical outcomes, and insights from recent studies. Although emerging tools such as biomarker-guided programming and predictive modeling are gaining interest, the focus of this review is on existing clinical literature shaping programming today.

Summary: Epilepsy is not solely a disorder of abnormal brain structure; it is fundamentally a disorder of disrupted brain networks and impaired communication across brain regions. Thalamic neuromodulation, once conceptualized as a fixed, anatomically guided intervention, is now undergoing a paradigm shift toward dynamic, network-informed modulation. Using tools such as stereo-EEG, diffusion MRI, and advanced connectomic analyses, we are entering a new era where neurostimulation strategies can be individualized, responsive, and aligned with the real-time neurophysiology and structural networks of each patient. By integrating anatomic and functional connectivity data, we are moving toward precision neuromodulation tailored to patient-specific seizure networks. In this review, we highlight the emerging role of functional and structural connectivity in refining our understanding of seizure dynamics and guiding neuromodulation interventions.