Journal Of Clinical Neurophysiology[JOURNAL]
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200 papers
Corpus Callosum-Mediated Interhemispheric Interactions in Cervical Spondylotic Myelopathy.
Lo YL, Hwang R, Teng PPC … +1 more , Tan YE
J Clin Neurophysiol · 2024 Jul · PMID 38922289 · Publisher ↗
PURPOSE: The corpus callosum is crucial for interhemispheric interactions in the motor control of limb functions. Human and animal studies suggested spinal cord pathologies may induce cortical reorganization in sensorimo...
PURPOSE: The corpus callosum is crucial for interhemispheric interactions in the motor control of limb functions. Human and animal studies suggested spinal cord pathologies may induce cortical reorganization in sensorimotor areas. We investigate participation of the corpus callosum in executions of a simple motor task in patients with cervical spondylotic myelopathy (CSM) using transcranial magnetic stimulation. METHODS: Twenty patients with CSM with various MRI grades of severity of cord compression were compared with 19 normal controls. Ipsilateral silent period, contralateral silent period, central motor conduction time, and transcallosal conduction time (TCT) were determined. RESULTS: In both upper and lower limbs, TCTs were significantly increased for patients with CSM than normal controls ( p < 0.001 for all), without side-to-side differences. Ipsilateral silent period and contralateral silent period durations were significantly increased bilaterally for upper limbs in comparison to controls ( p < 0.01 for all), without side-to-side differences. There were no significant correlations of TCT with central motor conduction time nor severity of CSM for both upper and lower limbs ( p > 0.05 for all) bilaterally. CONCLUSIONS: Previous transcranial magnetic stimulation studies show increased motor cortex excitability in CSM; hence, increased TCTs observed bilaterally may be a compensatory mechanism for effective unidirectional and uniplanar execution of muscle activation in the distal limb muscles. Lack of correlation of TCTs with severity of CSM or central motor conduction time may be in keeping with a preexistent role of the corpus callosum as a predominantly inhibitory pathway for counteracting redundant movements resulting from increased motor cortex excitability occurring after spinal cord lesions.
High-Frequency Stimulation of the Centromedian Thalamic Nucleus Aborts Seizures and Ictal Apnea.
Nathan CL, Gavvala JR, Chaitanya G … +6 more , Cunningham E, Lee JJ, Adney S, Rosenow J, Schuele S, Gerard E
J Clin Neurophysiol · 2024 Sep · PMID 38916942 · Publisher ↗
A 32-year-old right-handed woman presented with medically and surgically refractory left temporal neocortical epilepsy secondary to focal cortical dysplasia who underwent stereoelectroencephalography involving the centro...
A 32-year-old right-handed woman presented with medically and surgically refractory left temporal neocortical epilepsy secondary to focal cortical dysplasia who underwent stereoelectroencephalography involving the centromedian nucleus of the thalamus. With the use of real-time stereoelectroencephalography monitoring, four electroclinical seizures were aborted by administering high-frequency stimulation at the centromedian nucleus at seizure onset. Seizures before stimulation were all associated with ictal apnea, while those with stimulation had no ictal apnea. This case demonstrates how providing high-frequency stimulation to the centromedian nucleus of the thalamus can abort electroclinical seizures and ictal apnea.
Characterizing Seizure-Onset Patterns With the Responsive Neurostimulation System.
Haneef Z, Vallera AC, Vedantam S … +3 more , Feygin MS, Cleboski S, Gavvala JR
J Clin Neurophysiol · 2025 Feb · PMID 38916935 · Publisher ↗
PURPOSE: The responsive neurostimulation system (RNS) aims to improve seizures by delivering electrical stimulation in response to epileptiform patterns detected by electrocorticograms. Seizure-onset patterns (SOPs) corr...
PURPOSE: The responsive neurostimulation system (RNS) aims to improve seizures by delivering electrical stimulation in response to epileptiform patterns detected by electrocorticograms. Seizure-onset patterns (SOPs) correspond to outcomes in intracranial EEG (IC-EEG), although whether this is true for RNS is unknown. This study characterizes common RNS SOPs and correlates them with seizure outcomes. METHODS: Among 40 patients with RNS implants, long-episode electrocorticogram characteristics of each patient's seizures were classified by visual analysis as one of the eight patterns previously described in IC-EEG. Correlation between each type of SOP and eventual seizure outcome was analyzed, with ≥50% improvement in a number of patient-reported seizure counts defined as a favorable outcome. RESULTS: Across 263 LEs analyzed, the most common SOP observed was low-voltage fast activity. There was no difference between the distribution of RNS SOPs and that of IC-EEG SOPs described in the literature (Kolmogorov-Smirnov test, P = 0.98). Additionally, there was no correlation between any particular SOP and favorable outcomes (Fisher's omnibus test, P = 0.997). CONCLUSION: This initial description of RNS SOPs finds them to be similar to previously described IC-EEG SOPs, which suggests similar prognostic/therapeutic potential. However, we found that RNS efficacy is independent of patient SOP, suggesting that RNS is likely an equally effective treatment for all SOPs. Future research on stimulation parameters for particular RNS SOPs and correlation with IC-EEG SOPs in the same patients would be instrumental in guiding personalized neurostimulation.
Survey of Continuous EEG Monitoring Practices in the United States.
Kayal G, Oliveira KN, Haneef Z
J Clin Neurophysiol · 2025 Mar · PMID 38916934 · Publisher ↗
OBJECTIVE: Continuous EEG (cEEG) practice has markedly changed over the last decade given its utility in improving critical care outcomes. However, there are limited data describing the current cEEG infrastructure in US...
OBJECTIVE: Continuous EEG (cEEG) practice has markedly changed over the last decade given its utility in improving critical care outcomes. However, there are limited data describing the current cEEG infrastructure in US hospitals. METHODS: A web-based cEEG practice survey was sent to neurophysiologists at 123 ACGME-accredited epilepsy or clinical neurophysiology programs. RESULTS: Neurophysiologists from 100 (81.3%) institutions completed the survey. Most institutions had 3 to 10 EEG faculty (80.0%), 1 to 5 fellows (74.8%), ≥6 technologists (84.9%), and provided coverage to neurology ICUs with >10 patients (71.0%) at a time. Round-the-clock EEG technologist coverage was available at most (90.0%) institutions with technologists mostly being in-house (68.0%). Most institutions without after-hours coverage (8 of 10) attributed this to insufficient technologists. The typical monitoring duration was 24 to 48 hours (23.0 and 40.0%), most commonly for subclinical seizures (68.4%) and spell characterization (11.2%). Larger neurology ICUs had more EEG technologists ( p = 0.02), fellows ( p = 0.001), and quantitative EEG use ( p = 0.001). CONCLUSIONS: This survey explores current cEEG practice patterns in the United States. Larger centers had more technologists and fellows. Overall technologist numbers are stable over time, but with a move toward more in-hospital compared with home-based coverage. Reduced availability of EEG technologists was a major factor limiting cEEG availability at some centers.
Patient Handoff Practices at the Epilepsy Centers in the United States: A Survey of the Medical Directors.
Selioutski O, Herman S, Ritzl EK … +2 more , Garlinghouse M, Taraschenko O
J Clin Neurophysiol · 2025 Feb · PMID 38916933 · Publisher ↗
PURPOSE: Communication failure is one of the most significant causes of medical errors. Providing care to patients with seizures at comprehensive epilepsy centers requires uninterrupted coverage and a multidisciplinary a...
PURPOSE: Communication failure is one of the most significant causes of medical errors. Providing care to patients with seizures at comprehensive epilepsy centers requires uninterrupted coverage and a multidisciplinary approach. However, handoff practices in these settings have not been comprehensively assessed, and recommendations for their standardization are currently lacking. The aim of this observational study was to define the scope of existing practices for patient handoffs across epilepsy centers in the United States and provide relevant recommendations. METHODS: A 79-question survey was developed to establish the patterns of transition of care for patients undergoing continuous EEG recording, including the periodicity of handoffs and specifics of the relevant workflow. With permission from the National Association of Epilepsy Centers (NAEC), the survey was distributed to the medical directors of all Level 3 and 4 NAEC-accredited epilepsy centers in the United States. RESULTS: The responses were obtained from 70 institutions yielding a survey response rate of 26%. Of these, more than 77% had established weekly handoff processes for both the epilepsy monitoring unit and continuous EEG (cEEG) monitoring services. However, only 53% and 43% of centers had procedures for daily service transfers for the patients admitted to the epilepsy monitoring unit or the patients undergoing cEEG, respectively. The patterns of handoffs were complex and utilized group handoffs in < 50% of institutions. In most centers (>70%), patient data transmitted through handoffs included history, clinical information, and EEG findings. However, templates were not applied to standardize this information. All participants agreed or strongly agreed that a culture of patient safety was maintained in their place of practice; however, 12% of participants felt that insufficient time was allowed to discuss these patients or carry out the handoffs without interruptions. CONCLUSIONS: Existing handoff practices are not uniform or fully established across epilepsy centers in the United States. This study recommends that guidelines for formal handoff procedures be developed and introduced as a quality metric for all NAEC-accredited epilepsy centers.
Direct (D)-Wave Monitoring Enhancement With Subdural Electrode Placement: A Case Series.
Shah HA, Chen A, Green R … +5 more , Ber R, D'Amico RS, Sciubba DM, Lo SL, Silverstein JW
J Clin Neurophysiol · 2025 Mar · PMID 38916920 · Publisher ↗
PURPOSE: Direct-wave (D-wave) neuromonitoring is a direct measure of corticospinal tract integrity that detects potential injury during spinal cord surgery. Epidural placement of electrodes used for D-wave measurements c...
PURPOSE: Direct-wave (D-wave) neuromonitoring is a direct measure of corticospinal tract integrity that detects potential injury during spinal cord surgery. Epidural placement of electrodes used for D-wave measurements can result in high electrical impedances resulting in substantial signal noise that can compromise signal interpretation. Subdural electrode placement may offer a solution. METHODS: Medical records for consecutive patients with epidural and subdural D-wave monitoring were reviewed. Demographic and clinical information including preoperative and postoperative motor strength were recorded. Neuromonitoring charts were reviewed to characterize impedances and signal amplitudes of D-waves recorded epidurally (before durotomy) and subdurally (following durotomy). Nonparametric statistics were used to compare epidural and subdural D-waves. RESULTS: Ten patients (50% women, median age 50.5 years) were analyzed, of which five patients (50%) were functionally independent (modified McCormick grade ≤ II) preoperatively. D-waves were successfully acquired by subdural electrodes in eight cases and by epidural electrodes in three cases. Subdural electrode placement was associated with lower impedance values ( P = 0.011) and a higher baseline D-wave amplitude ( P = 0.007) relative to epidural placement. No association was observed between D-wave obtainability and functional status, and no adverse events relating to subdural electrode placement were encountered. CONCLUSIONS: Subdural electrode placement allows successful D-wave acquisition with accurate monitoring, clearer waveforms, and a more optimal signal-to-noise ratio relative to epidural placement. For spinal surgeries where access to the subdural compartment is technically safe and feasible, surgeons should consider subdural placement when monitoring D-waves to optimize clinical interpretation.
Does Hyperventilation Increase the Diagnostic Yield of the Routine Electroencephalogram: A Retrospective Analysis of Adult and Pediatric Cohorts.
Nadarajah N, Fahey M, Seneviratne U
J Clin Neurophysiol · 2024 Nov · PMID 38916885 · Publisher ↗
PURPOSE: While hyperventilation (HV) increases the diagnostic yield of EEG in children, there is conflicting evidence to support its application in adults. For the first time in history, a large cohort of patients has un...
PURPOSE: While hyperventilation (HV) increases the diagnostic yield of EEG in children, there is conflicting evidence to support its application in adults. For the first time in history, a large cohort of patients has undergone EEGs without HV during the COVID-19 pandemic. Utilizing this opportunity, we sought to investigate whether HV increases the diagnostic yield of EEG in children compared with adults. METHODS: Patients aged six years and above who had routine EEGs at Monash Health between January 2019 and December 2020 were studied. The cohort was divided into two, pediatric (younger than 18 years) and adult (18 years or older). Epileptiform abnormalities (ictal and interictal) were the outcomes investigated. The effect of HV was examined with logistic regression to determine odds ratios with 95% confidence intervals. RESULTS: In total, we studied 3,273 patients (pediatric = 830, adult = 2,443). In the pediatric cohort, HV significantly increased the diagnostic yield of absence seizures ( p = 0.01, odds ratios 2.44, 95% confidence intervals 1.21-4.93). In adults, HV did not increase the yield of absence seizures ( p = 0.34, odds ratios 0.36, 95% confidence intervals 0.05-2.88). Interictal epileptiform discharges during HV were significantly more frequent in children compared with adults ( p < 0.001, odds ratios 3.81, 95% confidence intervals 2.51-5.77). CONCLUSIONS: Hyperventilation is useful to increase the yield of interictal epileptiform discharges and absence seizures in pediatric patients but not in adults. Hence, routine EEG may be recorded in adults without HV when it is unsafe to perform.
Electrocorticographic Patterns in Frontal Epilepsy and Long-Term Outcomes.
J Clin Neurophysiol · 2024 Jun · PMID 38916879 · Publisher ↗
INTRODUCTION: The prognostic significance of tailored resection guided with intraoperative electrocorticography (iECoG) in frontal lobe epilepsy surgery has not been fully elucidated. OBJECTIVES: To analyze influence of...
INTRODUCTION: The prognostic significance of tailored resection guided with intraoperative electrocorticography (iECoG) in frontal lobe epilepsy surgery has not been fully elucidated. OBJECTIVES: To analyze influence of preresection and postresection iECoG patterns on long-term seizure control of adults with frontal lobe epilepsy undergoing epilepsy surgery. METHODS: We retrospectively analyzed 27 patients undergoing epilepsy surgery from two centers with preresection and postresection iECoG and reported clinical variables, preresection and postresection iECoG patterns, and outcome using the Engel Outcome Scale. Descriptive statistics, Kaplan-Meier, the logistic regression model, and analysis of variance tests were used. RESULTS: Fifteen males (55.6%), a mean and mode follow-up after surgery of 43 (range 2-117) and 19 months, respectively. At 6 months, seizure frequency outcome according to Engel Scale was I 74.1% (20/27), II 7.4% (2/27), III 3.7% (1/27), and IV 14.8% (4/27). We found that 51.9% (14/27) and 40.8% (11/27) of patients without residual epileptiform discharges in postresective iECoG become seizure-free at 6 and 12 months of follow-up, respectively, compared with other postresective iECoG patterns. CONCLUSIONS: Disregarding the presence of lack of residual epileptiform discharges (interictal epileptiform discharges) after resection, Engel I outcome was seen between 74.1% and 63% at 6- and 12-month postresection follow-up, suggesting the outcome might be in relation with other factors.
Interictal Electroencephalography and Functional Magnetic Resonance Imaging Reveals Involvement of Mesial Anterior Frontal Structures in Patients With Hyperkinetic Semiology Type I.
Kokkinos V
J Clin Neurophysiol · 2025 May · PMID 38913939 · Publisher ↗
PURPOSE: This work investigates the presence of common anatomic regions associated with interictal activity in patients with hyperkinetic seizures type I by means of concurrent electroencephalography and functional magne...
PURPOSE: This work investigates the presence of common anatomic regions associated with interictal activity in patients with hyperkinetic seizures type I by means of concurrent electroencephalography and functional magnetic resonance imaging. METHODS: Six patients with hyperkinetic seizures type I were evaluated with video-EEG and electroencephalography and functional magnetic resonance imaging in the context of their presurgical evaluation. Statistical Parametric Mapping was used to perform a correlation study between the occurrence of interictal spikes on EEG and suprathreshold blood oxygen level-dependent changes in the whole-brain volume. RESULTS: In all patients, Statistical Parametric Mapping revealed suprathreshold blood oxygen level-dependent clusters in the mesial anterior frontal areas, including the rostral mesial superior frontal gyrus and the anterior cingulate, associated with the patients' typical interictal activity. CONCLUSIONS: The electroencephalography and functional magnetic resonance imaging findings contribute to our understanding of hyperkinetic seizures type I semiology generation and can inform stereo-EEG targeting for surgical planning in refractory cases.
Contraction-Induced H Reflexes of the Upper and Lower Limbs in Healthy Adults.
Winkel A, Cook M, Roberts L
J Clin Neurophysiol · 2025 Feb · PMID 38913764 · Publisher ↗
PURPOSE: Contraction-induced H reflexes are a late neurophysiologic response elicited with submaximal nerve stimulation during isometric muscle contraction. Mediated by spinal pathways, like other H reflexes, their use h...
PURPOSE: Contraction-induced H reflexes are a late neurophysiologic response elicited with submaximal nerve stimulation during isometric muscle contraction. Mediated by spinal pathways, like other H reflexes, their use has remained somewhat limited despite a long history of development dating back to the original description by Hoffman. There is a paucity of data on normal reference ranges, which this article aims to add to. METHODS: Contraction-induced H reflexes were elicited from the first dorsal interosseous, flexor carpi radialis, and tibialis anterior bilaterally in 100 healthy volunteers. Reference values, including side-to-side variation, were calculated. Pearson test and multiple regression were used to evaluate the relationship of H-reflex latency to height, age, and sex of participants. RESULTS: The mean onset latencies of 28.00, 17.44, and 31.10 ms were seen for first dorsal interosseous, flexor carpi radialis, and tibialis anterior muscles, respectively. The calculated allowable side-to-side latency difference in individual participants was 3 to 4 ms. A correlation to participant height was seen. CONCLUSIONS: This work provides normal reference values of contraction-induced H reflexes to three muscles, including allowable side-to-side variation. The latter suggests that bilateral testing evaluating for asymmetry within an individual is likely to be optimally sensitive. The relationship to height is also confirmed.
Intraoperative Neurophysiological Monitoring in Tethered Cord Syndrome Surgery: Predictive Values and Clinical Outcome.
Squintani G, Basaldella F, Badari A … +8 more , Rasera A, Tramontano V, Pinna G, Moscolo F, Soda C, Ricci U, Ravenna G, Sala F
J Clin Neurophysiol · 2025 Mar · PMID 38905022 · Publisher ↗
INTRODUCTION: "Tethered cord syndrome" (TCS) refers to a congenital abnormality associated with neurological signs and symptoms. The aim of surgery is to prevent or arrest their progression. This study reports a retrospe...
INTRODUCTION: "Tethered cord syndrome" (TCS) refers to a congenital abnormality associated with neurological signs and symptoms. The aim of surgery is to prevent or arrest their progression. This study reports a retrospective case series of tethered cord syndrome surgeries, supported by intraoperative neurophysiological monitoring. METHODS: The case series comprises 50 surgeries for tethered cord syndrome in which multimodal intraoperative neurophysiological monitoring was performed using motor evoked potentials (transcranial motor evoked potentials [TcMEPs]), tibial nerve somatosensory evoked potentials (TNSEPs), and pudendal-anal reflex (PAR). The intraoperative neurophysiological monitoring results are reported and correlated with clinical outcomes. RESULTS: Sensitivity, specificity, and negative predictive value were high for TcMEPs and TNSEPs, while PAR exhibited low sensitivity and positive predictive value but high specificity and negative predictive value. Fisher's exact test revealed a significant correlation between changes in TcMEPs, TNSEPs, and clinical outcome ( P < 0.000 and P = 0.049 respectively), but no correlation was detected between PAR and urinary/anal function ( P = 0.497). CONCLUSIONS: While TcMEPs and TNSEPs were found to be reliable intraoperative neurophysiological monitoring parameters during tethered cord syndrome surgery, PAR had low sensitivity and positive predictive value probably because the reflex is not directly related to bladder function and because its multisynaptic pathway may be sensitive to anesthetics. New onset muscle weakness and sensory deficits were related to postoperative changes in TcMEPs and TNSEPs, whereas changes in PAR did not predict bladder/urinary impairment. Urinary deficits may be predicted and prevented with other neurophysiological techniques, such as the bladder-anal reflex.
Normative Data and Quantile Regression Analysis of the Sural-to-Radial Nerve Amplitude Ratio.
Pourhamidi K
J Clin Neurophysiol · 2025 Feb · PMID 38904541 · Publisher ↗
PURPOSE: The aim of this study was to establish normative data for the sural-to-radial nerve amplitude ratio (SRAR) and develop a quantile regression model for individualized cutoff values. METHODS: A cohort of 68 health...
PURPOSE: The aim of this study was to establish normative data for the sural-to-radial nerve amplitude ratio (SRAR) and develop a quantile regression model for individualized cutoff values. METHODS: A cohort of 68 healthy individuals (36 female participants) aged 20 to 59 years was recruited. Sensory nerve conduction studies were conducted to measure sural and radial sensory nerve action potential amplitudes. Quantile regression analysis was used to determine the fifth percentile of SRAR after adjusting for age, sex, and other demographic variables. RESULTS: This study found significant differences in body height and weight between the sexes, with radial sensory nerve action potential being higher in female participants. The sural-to-radial nerve amplitude ratio was negatively correlated with age ( r = -0.3, p = 0.007) and showed significant sex differences. The final regression equation, SRAR = 0.519 - 0.006 × age + 0.046 × sex (1 = male, 0 = female), was developed for the fifth percentile cutoff, accounting for age and sex. CONCLUSIONS: This study establishes normative SRAR data and introduces a novel quantile regression approach to determine individualized cutoff values. Age and sex are critical factors for SRAR variation, necessitating tailored diagnostic criteria for neuropathy assessment. This model enhances diagnostic accuracy and potentially reduces misdiagnosis in clinical settings. Further research is recommended to validate the clinical applicability of SRAR across different types of neuropathies.
The First 100 Seconds of Sleep of rEEGs Can Be a Reliable Scoring Method for D/EE-SWAS.
Kulkarni N, Klamer B, Drees M … +1 more , Twanow JD
J Clin Neurophysiol · 2025 Feb · PMID 38857411 · Publisher ↗
PURPOSE: Developmental/epileptic encephalopathy with spike wave activation with sleep, formerly known as electrical status epilepticus in sleep, is an electrographic pattern in which the interictal epileptiform activity...
PURPOSE: Developmental/epileptic encephalopathy with spike wave activation with sleep, formerly known as electrical status epilepticus in sleep, is an electrographic pattern in which the interictal epileptiform activity is augmented by transition to sleep. Recent studies demonstrate the utility of the first 100 seconds of sleep of long-term monitoring (LTM) as a scoring method for electrical status epilepticus in sleep. Our aim was to measure the reliability of the spike-wave index (SWI) of the first 100 seconds of sleep of routine EEG (rEEG) as a tool for diagnosis of developmental/epileptic encephalopathy with spike wave activation with sleep. METHODS: Approximately three hundred forty LTMs were reviewed, and 25 studies from 25 unique patients had comparable rEEGs. Two neurophysiologists calculated the SWI of the first 100 seconds of spontaneous stage II non-random eye movement sleep, the first 5-minute bin of sleep, and three separate 5-minute bins throughout sleep in LTM. This was compared to the SWI of the first 100 seconds of sleep in rEEG. Agreement was analyzed using Lin's concordance correlation coefficient (CCC). RESULTS: Using 50% as a diagnostic cut-off, we observed moderate agreement between the SWI of the first 100 seconds of sleep of rEEG and three bin LTM (CCC = 0.94, 95% CI: 0.88-0.97). Agreement was slightly higher for the comparison to first bin LTM SWI (CCC = 0.96, 95% CI: 0.92-0.98) and first 100 seconds LTM SWI (CCC = 0.96, 95% CI: 0.92-0.98). CONCLUSIONS: This study demonstrates the first 100 seconds of sleep of rEEG technique as a time efficient diagnostic tool for patients with concern for developmental/epileptic encephalopathy with spike wave activation with sleep.
Reflex Responses in Muscles of the Lower Extremities Elicited by Transcutaneous Stimulation of Cauda Equina: Part 1. Methodology and Normative Data.
Rimac J, Jančuljak D, Kovač B … +2 more , Jovičić M, Forjan J
J Clin Neurophysiol · 2025 Feb · PMID 38857374 · Publisher ↗
INTRODUCTION: Transcutaneous electrical stimulation is used to stimulate the dorsal roots of the cauda equina. Multiple elicited responses recorded in the lower extremity muscles are called posterior root muscle reflexes...
INTRODUCTION: Transcutaneous electrical stimulation is used to stimulate the dorsal roots of the cauda equina. Multiple elicited responses recorded in the lower extremity muscles are called posterior root muscle reflexes (PRMRs). Normal PRMR values in the muscles of healthy lower extremities have yet to be determined. METHODS: Thirty subjects without known lumbosacral spinal root illness were included in this study. Subsequently, they were subjected to transcutaneous electrical stimulation of the cauda equina. Posterior root muscle reflex was recorded in the four muscle groups of both lower extremities. We elicited multiple PRMR and examined their characteristics in order to establish normal electrophysiological parameter values. RESULTS: Posterior root muscle reflex was successfully elicited in the tibialis anterior (96.7%), gastrocnemius (100%), quadriceps femoris (93.3%), and hamstring (96.7%). No statistically significant differences were found in the intensity of stimulation, latencies, or area under the PRMR between the right and left leg muscles. The area under PRMR varied significantly among the participants. Higher body weight and abdominal girth showed a significant positive correlation with stimulation intensity for eliciting PRMR, and a significant negative correlation with the area under PRMR. Older age showed a significant negative correlation with the success of eliciting PRMR and the area under the PRMR. CONCLUSIONS: Posterior root muscle reflex is a noninvasive and successful method for eliciting selective reflex responses of cauda equina posterior roots. Obtained values could be used in future studies to evaluate the utility of this methodology in clinical practice. This methodology could improve testing of the proximal lumbosacral nervous system functional integrity.
Characteristics and Usefulness of Neurophysiological Monitoring in Corrective Procedures for Abnormally Curved Spine in Young Patients.
Michaeli A, Miller S, Danto J … +3 more , Arzi H, Schroeder JE, Ovadia D
J Clin Neurophysiol · 2025 Feb · PMID 38857370 · Publisher ↗
PURPOSE: To identify and characterize events of deterioration in intraoperative neuromonitoring data during correction procedures for thoracic and lumbar abnormal spinal curvature in young patients. METHODS: Records of 1...
PURPOSE: To identify and characterize events of deterioration in intraoperative neuromonitoring data during correction procedures for thoracic and lumbar abnormal spinal curvature in young patients. METHODS: Records of 1,127 cases were retrospectively reviewed to identify events with deterioration of the neuromonitoring data. General etiological and demographic variables were summarized, and neuromonitoring events were studied and characterized. RESULTS: Adolescent idiopathic cases were associated with female dominance and older age. Nonadolescent idiopathic cases were associated with a higher rate of neuromonitoring events. The neuromonitoring events evolved during the different procedural stages, were primarily reflected in the motor-evoked potential data and affected a range of neural structures to varying degrees. Most of the events were resolved, partially or completely, following a corresponding intervention by the surgical team, before the end of the procedure. Significant immediate weakness of the lower extremities was demonstrated in patients with unresolved neuromonitoring events, most of them were nonadolescent idiopathic patients. CONCLUSIONS: Neurophysiological monitoring enables the intraoperative assessment of the integrity of neural pathways and allows the detection of surgery-related impending neural injuries. Neuromonitoring contributes to intraoperative decision making, either when data are uneventful and allow confident continuation or when data deteriorate and lead to corresponding intervention. Further awareness should be paid to the vulnerable characteristics of the patient, surgery course, and neuromonitoring data. Proper interpretation of the neuromonitoring data, together with corresponding intervention by the surgeon when necessary, has the potential to reduce postoperative neurological insults and improve clinical outcomes.
A Comparison of Automatically Extracted Quantitative EEG Features for Seizure Risk Stratification in Neonatal Encephalopathy.
Keene JC, Loe ME, Fulton T … +7 more , Keene M, Morrissey MJ, Tomko SR, Vesoulis ZA, Zempel JM, Ching S, Guerriero RM
J Clin Neurophysiol · 2025 Jan · PMID 38857366 · Full text
PURPOSE: Seizures occur in up to 40% of neonates with neonatal encephalopathy. Earlier identification of seizures leads to more successful seizure treatment, but is often delayed because of limited availability of contin...
PURPOSE: Seizures occur in up to 40% of neonates with neonatal encephalopathy. Earlier identification of seizures leads to more successful seizure treatment, but is often delayed because of limited availability of continuous EEG monitoring. Clinical variables poorly stratify seizure risk, and EEG use to stratify seizure risk has previously been limited by need for manual review and artifact exclusion. The goal of this study is to compare the utility of automatically extracted quantitative EEG (qEEG) features for seizure risk stratification. METHODS: We conducted a retrospective analysis of neonates with moderate-to-severe neonatal encephalopathy who underwent therapeutic hypothermia at a single center. The first 24 hours of EEG underwent automated artifact removal and qEEG analysis, comparing qEEG features for seizure risk stratification. RESULTS: The study included 150 neonates and compared the 36 (23%) with seizures with those without. Absolute spectral power best stratified seizure risk with area under the curve ranging from 63% to 71%, followed by range EEG lower and upper margin, median and SD of the range EEG lower margin. No features were significantly more predictive in the hour before seizure onset. Clinical examination was not associated with seizure risk. CONCLUSIONS: Automatically extracted qEEG features were more predictive than clinical examination in stratifying neonatal seizure risk during therapeutic hypothermia. qEEG represents a potential practical bedside tool to individualize intensity and duration of EEG monitoring and decrease time to seizure recognition. Future work is needed to refine and combine qEEG features to improve risk stratification.
Methods of Evaluating EEG Reactivity in Adult Intensive Care Units: A Review.
Hwang J, Cho SM, Geocadin R … +1 more , Ritzl EK
J Clin Neurophysiol · 2024 Nov · PMID 38857365 · Publisher ↗
PURPOSE: EEG reactivity (EEG-R) has become widely used in intensive care units for diagnosing and prognosticating patients with disorders of consciousness. Despite efforts toward standardization, including the establishm...
PURPOSE: EEG reactivity (EEG-R) has become widely used in intensive care units for diagnosing and prognosticating patients with disorders of consciousness. Despite efforts toward standardization, including the establishment of terminology for critical care EEG in 2012, the processes of testing and interpreting EEG-R remain inconsistent. METHODS: A review was conducted on PubMed following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Inclusion criteria consisted of articles published between January 2012, and November 2022, testing EEG-R on adult intensive care unit patients. Exclusion criteria included articles focused on highly specialized stimulation equipment or animal, basic science, or small case report studies. The Quality In Prognostic Studies tool was used to assess risk of bias. RESULTS: One hundred and five articles were identified, with 26 variables collected for each. EEG-R testing varied greatly, including the number of stimuli (range: 1-8; 26 total described), stimulus length (range: 2-30 seconds), length between stimuli (range: 10 seconds-5 minutes), frequency of stimulus application (range: 1-9), frequency of EEG-R testing (range: 1-3 times daily), EEG electrodes (range: 4-64), personnel testing EEG-R (range: neurophysiologists to nonexperts), and sedation protocols (range: discontinuing all sedation to no attempt). EEG-R interpretation widely varied, including EEG-R definitions and grading scales, personnel interpreting EEG-R (range: EEG specialists to nonneurologists), use of quantitative methods, EEG filters, and time to detect EEG-R poststimulation (range: 1-30 seconds). CONCLUSIONS: This study demonstrates the persistent heterogeneity of testing and interpreting EEG-R over the past decade, and contributing components were identified. Further many institutional efforts must be made toward standardization, focusing on the reproducibility and unification of these methods, and detailed documentation in the published literature.
Detection of Language Lateralization Using Spectral Analysis of EEG.
Nix KC, Oh A, Goad BS … +3 more , Wu W, Lucas MV, Baumer FM
J Clin Neurophysiol · 2024 May · PMID 38710040 · Full text
PURPOSE: Language lateralization relies on expensive equipment and can be difficult to tolerate. We assessed if lateralized brain responses to a language task can be detected with spectral analysis of electroencephalogra...
PURPOSE: Language lateralization relies on expensive equipment and can be difficult to tolerate. We assessed if lateralized brain responses to a language task can be detected with spectral analysis of electroencephalography (EEG). METHODS: Twenty right-handed, neurotypical adults (28 ± 10 years; five males) performed a verb generation task and two control tasks (word listening and repetition). We measured changes in EEG activity elicited by tasks (the event-related spectral perturbation [ERSP]) in the theta, alpha, beta, and gamma frequency bands in two language (superior temporal and inferior frontal [ST and IF]) and one control (occipital [Occ]) region bilaterally. We tested whether language tasks elicited (1) changes in spectral power from baseline (significant ERSP) at any region or (2) asymmetric ERSPs between matched left and right regions. RESULTS: Left IF beta power (-0.37±0.53, t = -3.12, P = 0.006) and gamma power in all regions decreased during verb generation. Asymmetric ERSPs (right > left) occurred between the (1) IF regions in the beta band (right vs. left difference of 0.23±0.37, t(19) = -2.80, P = 0.0114) and (2) ST regions in the alpha band (right vs. left difference of 0.48±0.63, t(19) = -3.36, P = 0.003). No changes from baseline or hemispheric asymmetries were noted in language regions during control tasks. On the individual level, 16 (80%) participants showed decreased left IF beta power from baseline, and 16 showed ST alpha asymmetry. Eighteen participants (90%) showed one of these two findings. CONCLUSIONS: Spectral EEG analysis detects lateralized responses during language tasks in frontal and temporal regions. Spectral EEG analysis could be developed into a readily available language lateralization modality.
Ictal Direct Current Shifts Preceded Much Earlier Than High Frequency Oscillations After Status: Is It the Effect of Status or Antiseizure Medication?
Kanazawa K, Kajikawa S, Matsumoto R … +10 more , Takatani M, Nakatani M, Daifu-Kobayashi M, Imamura H, Kikuchi T, Kunieda T, Miyamoto S, Takahashi R, Matsuhashi M, Ikeda A
J Clin Neurophysiol · 2025 Feb · PMID 38687304 · Publisher ↗
PURPOSE: While spikes and sharp waves are considered as markers of epilepsy in conventional electroencephalography, ictal direct current (DC) shifts and high-frequency oscillations (HFOs) appear to be useful biomarkers f...
PURPOSE: While spikes and sharp waves are considered as markers of epilepsy in conventional electroencephalography, ictal direct current (DC) shifts and high-frequency oscillations (HFOs) appear to be useful biomarkers for epileptogenicity. We analyzed how ictal DC shifts and HFOs were affected by focal status epilepticus and antiseizure medications (ASMs). METHODS: A 20-year-old female patient who underwent long-term intracranial electrode implantation for epilepsy surgery presented with 72 habitual seizures and a focal status epilepticus episode lasting for 4 h. Ten, 3, and 10 consecutive habitual seizures were analyzed before the status, after the status, and after ASM (valproate) loading, respectively. RESULTS: Before and immediately after the status, ictal DC shifts remained the same in terms of the amplitude, duration, and slope of DC shifts. High-frequency oscillations also remained the same in terms of the duration, frequency, and power except for the power of the lower frequency band. After ASM loading, the duration, amplitude, and slope of the ictal DC shift were significantly attenuated. The duration, frequency, and power of the HFOs were significantly attenuated. Furthermore, the interval between the DC onset and HFO onset was significantly longer and the interval between the HFO onset and ictal DC shift peak was significantly shorter. CONCLUSIONS: The attenuation of ictal DC shifts and HFOs after ASM loading implies that astrocyte and neuronal activity may be both attenuated by ASMs. This finding may help with our understanding of the pathophysiology of epilepsy and can aid with the discovery of new approaches for epilepsy management.
Late-Onset Findings During Extended EEG Monitoring Are Rare in Critically Ill Children.
Fung FW, Parikh DS, Walsh K … +4 more , Fitzgerald MP, Massey SL, Topjian AA, Abend NS
J Clin Neurophysiol · 2025 Feb · PMID 38687298 · Full text
PURPOSE: Electrographic seizures (ES) are common in critically ill children undergoing continuous EEG (CEEG) monitoring, and previous studies have aimed to target limited CEEG resources to children at highest risk of ES....
PURPOSE: Electrographic seizures (ES) are common in critically ill children undergoing continuous EEG (CEEG) monitoring, and previous studies have aimed to target limited CEEG resources to children at highest risk of ES. However, previous studies have relied on observational data in which the duration of CEEG was clinically determined. Thus, the incidence of late occurring ES is unknown. The authors aimed to assess the incidence of ES for 24 hours after discontinuation of clinically indicated CEEG. METHODS: This was a single-center prospective study of nonconsecutive children with acute encephalopathy in the pediatric intensive care unit who underwent 24 hours of extended research EEG after the end of clinical CEEG. The authors assessed whether there were new findings that affected clinical management during the extended research EEG, including new-onset ES. RESULTS: Sixty-three subjects underwent extended research EEG. The median duration of the extended research EEG was 24.3 hours (interquartile range 24.0-25.3). Three subjects (5%) had an EEG change during the extended research EEG that resulted in a change in clinical management, including an increase in ES frequency, differential diagnosis of an event, and new interictal epileptiform discharges. No subjects had new-onset ES during the extended research EEG. CONCLUSIONS: No subjects experienced new-onset ES during the 24-hour extended research EEG period. This finding supports observational data that patients with late-onset ES are rare and suggests that ES prediction models derived from observational data are likely not substantially underrepresenting the incidence of late-onset ES after discontinuation of clinically indicated CEEG.
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