Journal of Clinical Neurophysiology最新文献

Purpose: Electroencephalography (EEG) remains underutilized for stroke characterization. We sought to assess the performance of the EEG Correlate Of Injury to the Nervous system (COIN) index, a quantitative metric designed for stroke recognition in children, in discriminating large from small ischemic strokes in adults.

Methods: Retrospective, single-center cohort of adults with acute (within 7 days) ischemic stroke who underwent at least 8 hours of continuous EEG monitoring in hospital. Stroke size was categorized as large or small based on a threshold of 100 mL using the ABC/2 approach. EEG data were processed on MATLAB. COIN was independently calculated from consecutive 4-second EEG epochs. Student t-test and logistic regression were used to assess COIN performance in stroke size discrimination across the entire recording; random forest classification was used to determine COIN performance in limited EEG time windows ranging from 5 to 30 minutes in duration.

Results: Thirty-five patients with mean age 67 (SD ± 17) years were analyzed with mean 4.5 ± 1.3 hours of clean EEG per patient. Ten patients had large stroke and 25 had small stroke. Participants with large strokes had larger COIN values than those with small strokes (-53 vs. -16, P = 0.0001). Logistic regression for stroke size classification model showed accuracy 83% ± 8%, sensitivity 70%±15%, specificity 88%±8%, and area under the receiver operator curve 0.75±0.10. Random Forest Classification performance was similar using 5 or 30 minutes of EEG data with accuracy 81% to 82%, specificity 91% to 92%, and sensitivity 55% to 58%, respectively.

Conclusions: COIN differentiated large from small acute ischemic strokes in this single-center cohort. Prospective evaluation in larger multicenter data sets is necessary to determine COIN utility as an aid for bedside detection of large ischemic strokes in contexts where neuroimaging cannot be easily obtained or when neurologic examination is limited by sedation or neuromuscular blockade.

Purpose: Neonatal encephalopathy (NE) is a commonly encountered, highly morbid condition with a pressing need for accurate epilepsy prognostication. We evaluated the use of automated EEG for prediction of early life epilepsy after NE treated with therapeutic hypothermia (TH).

Methods: We conducted retrospective analysis of neonates with moderate-to-severe NE who underwent TH at a single center. The first 24 hours of EEG data underwent automated artifact removal and quantitative EEG (qEEG) analysis with subsequent evaluation of qEEG feature accuracy at the 1st and 20th hour for epilepsy risk stratification.

Results: Of 144 neonates with NE, 67 completed at least 1 year of follow-up with a neurologist and were included. Twenty-three percent had seizures ( N = 18) in the NICU and 9% developed epilepsy ( N = 6). We found multiple automatically extracted qEEG features were predictive of epilepsy as early as the first hour of life, with improved risk stratification during the first day of life. In the 20th hour EEG, absolute spectral power best stratified epilepsy risk, with area under the curve ranging from 76% to 83% across spectral frequencies, followed by range EEG features including width, SD, upper and lower margin, and median. Clinical examination did not significantly predict epilepsy development.

Conclusions and significance: Quantitative EEG features significantly predicted early life epilepsy after NE. Automatically extracted qEEG may represent a practical tool for improving risk stratification for post-NE epilepsy development. Future work is needed to validate using automated EEG for prediction of epilepsy in a larger cohort.

Purpose: Repetitive transcranial magnetic stimulation (rTMS) is a potentially effective, noninvasive tool for language mapping. However, there is a paucity of data in pediatric patients. In this study, we aimed to map language sites in healthy pediatric participants with navigated rTMS.

Methods: Children aged 5 to 18 years underwent bilateral language mapping. Stimulation was delivered at 5 Hz during visual-naming and auditory verb-generation tasks in 1 to 2 second bursts. We targeted 33 standardized sites per hemisphere. In total, 34 participants completed the visual-naming task, and 27 participants completed the verb-generation task. Lateralization index (LI) and Wilcoxon signed-rank test were used to assess language lateralization. A difference of least squares means model was developed to determine the prevalence of visual-naming and verb-generation errors within lobar and hemispheric regions.

Results: Weak left lateralization was observed for visual naming (LI 0.14; p = 0.038), and no lateralization was observed for verb generation (LI 0.08; p = 0.269). Using multiple least squares regression, left hemisphere errors were more likely to occur than right hemisphere errors for visual naming (OR 1.23; 95% CI 1.06-1.44), but no lateralization effect was observed for verb-generation errors (OR 1.11; 95% CI 0.93-1.27).

Conclusions: rTMS is likely to identify bilateral or weakly left-lateralized language sites in pediatric patients during language tasks. Although rTMS can be a useful noninvasive method for identifying potential language-positive sites, our results in healthy controls suggest that it cannot be used as a singular method for language mapping in the preoperative setting.

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.

Summary: 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.

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.

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.

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.

Introduction: Conventional EEG interpretation distinguishes spikes (20-70 ms) versus sharp waves (70-200 ms), but the rationale for this distinction is unclear. This preliminary study endeavors to correlate discharge duration with some clinical outcomes.

Methods: We measured spike and sharp wave duration for up to 10 discharges in 100 patients referred for routine, inpatient, or ambulatory EEGs. Excluded were generalized spikes, spike waves, polyspikes, seizures, or lateralized periodic discharges (LPDs).

Results: We measured 882 interictal discharges in 100 patients, comprising structural, genetic, autoimmune, and unknown etiologies. Epileptiform discharges, mainly temporal, were unilateral in 64 and bilateral or multifocal in 36 patients. Each record presented 3 to 10 discharges, with 74% having 10 or more. Mean discharge duration was 71.9 ± 31.4, range 15 to 200 ms. Most patients (87%) had mixed sharps and spikes, with 6% having only sharps and 7% having only spikes. Discharge durations within an individual patient were highly variable. Mean discharge duration and seizure frequency were poorly correlated ( r = -0.023, P = 0.82), as were discharge duration and number of antiseizure medications ( r = -0.027, P = 0.80).

Conclusions: In our series, discharge duration did not correlate with seizure frequency or number of antiseizures medicines. Only 13% of patients had exclusive spikes or sharp waves, suggesting that duration of an individual discharge is not a defining characteristic of that person's epilepsy. Although this study is small and preliminary, it suggests that the distinction between spike and sharp waves at 70 ms may not be clinically relevant and perhaps all epileptiform discharges could be called spikes.

Summary: The orbitofrontal cortex is central to decision making, reward valuation, emotional regulation, and goal-directed behavior. Although traditional cytoarchitectonic classifications, such as Brodmann map, identified multiple cortical areas within the orbitofrontal cortex, recent neuroimaging advancements such as the Human Connectome Project have refined our anatomical understanding in granular detail. This study characterizes the structural and functional connectivity of key orbitofrontal subregions, particularly Brodmann area 11, Brodmann area 13, Brodmann area 14, and Brodmann area 47, corresponding to Human Connectome Project areas 11L, 13L, orbitofrontal cortex (OFC)/polar orbitofrontal cortex, and 47m/47 s/a47r, respectively. Structural connectivity analyses reveal significant large white matter connections with the inferior frontal-occipital fasciculus, uncinate fasciculus, and pathways linking the OFC to the amygdala and temporal cortex. Functionally, 11L is involved in valuation and decision making, 13L contributes to emotion regulation, OFC/polar orbitofrontal cortex plays a key role in reward processing and self-referential cognition, and areas 47 m, 47 s, and a47r have a role in coordinating cognitive and emotional information, as well as language production and semantic processing. These subregions integrate sensory-affective information and support theory of mind and semantic processing. Disruptions in OFC connectivity contribute to neuropsychiatric and neurodegenerative disorders, inducing various symptoms of addiction, obesity, depression, Parkinson disease, and frontotemporal dementia, highlighting the relevance of our improved anatomical understanding of this region for targeted neuromodulation strategies. Importantly, this work leverages an anatomically precise nomenclature from the Human Connectome Project to refine our understanding of the OFC's connectivity, enabling more precise neuromodulatory targeting while improving the reproducibility and sharing of research findings of this region.