Journal articles: 'Epidural recordings'

1

Barnett, Gene H., Richard C. Burgess, Issam A. Award, George J. Skipper, Christopher R. Edwards, and Hans Luders. "Epidural Peg Electrodes for the Presurgical Evaluation of Intractable Epilepsy." Neurosurgery 27, no. 1 (1990): 113–15. http://dx.doi.org/10.1227/00006123-199007000-00016.

Full text

Abstract:

Abstract A new electrode design for the extradural recording of electrical brain activity is described. Epidural peg electrodes are implantable mushroom-shaped composites of Silastic clastomer and a stainless steel or platinum disc. These electrodes are useful for the preoperative mapping of seizure foci in some patients who have cranial defects or severe muscle artifacts on scalp recordings. They are also used for canvassing wide areas of cortex to determine whether a seizure is focal in origin, arises diffusely from a hemisphere, or has a bilateral origin. Advantages of epidural peg electrodes over screw and other types of epidural electrodes include low risk of infection or hemorrhage and improved patient comfort.

APA, Harvard, Vancouver, ISO, and other styles

2

Haumann, S., G. Bauernfeind, M. J. Teschner, et al. "Epidural recordings in cochlear implant users." Journal of Neural Engineering 16, no. 5 (2019): 056008. http://dx.doi.org/10.1088/1741-2552/ab1e80.

Full text

APA, Harvard, Vancouver, ISO, and other styles

3

Haumann, S., G. Bauernfeind, M. J. Teschner, et al. "Epidural recordings in cochlear implant users." Journal of Neural Engineering 16 (June 5, 2019): 1–13. https://doi.org/10.1088/1741-2552/ab1e80.

Full text

APA, Harvard, Vancouver, ISO, and other styles

4

Niedermeyer, Ernst, and Sumio Uematsu. "Epidural EEG Recordings in Candidates for Temporal Lobectomy." Journal of Clinical Neurophysiology 5, no. 4 (1988): 328. http://dx.doi.org/10.1097/00004691-198810000-00012.

Full text

APA, Harvard, Vancouver, ISO, and other styles

5

Bauernfeind, G., M. J. Teschner, S. C. Wriessnegger, A. Büchner, T. Lenarz, and S. Haumann. "Towards single-trial classification of invasively recorded auditory evoked potentials in cochlear implant users." Journal of Neural Engineering 19, no. 2 (2022): 026002. http://dx.doi.org/10.1088/1741-2552/ac572d.

Full text

Abstract:

Abstract Objective. One promising approach towards further improving cochlear implants (CI) is to use brain signals controlling the device in order to close the auditory loop. Initial electroencephalography (EEG) studies have already shown promising results. However, they are based on noninvasive measurements, whereas implanted electrodes are expected to be more convenient in terms of everyday-life usability. If additional measurement electrodes were implanted during CI surgery, then invasive recordings should be possible. Furthermore, implantation will provide better signal quality, higher robustness to artefacts, and thus enhanced classification accuracy. Approach. In an initial project, three additional epidural electrodes were temporarily implanted during the surgical procedure. After surgery, different auditory evoked potentials (AEPs) were recorded both invasively (epidural) and using surface electrodes, with invasively recorded signals demonstrated as being markedly superior. In this present analysis, cortical evoked response audiometry (CERA) signals recorded in seven patients were used for single-trial classification of sounds with different intensities. For classification purposes, we used shrinkage-regularized linear discriminant analysis (sLDA). Clinical speech perception scores were also investigated. Main results. Analysis of CERA data from different subjects showed single-trial classification accuracies of up to 99.2% for perceived vs. non-perceived sounds. Accuracies of up to 89.1% were achieved in classification of sounds perceived at different intensities. Highest classification accuracies were achieved by means of epidural recordings. Required loudness differences seemed to correspond to speech perception in noise. Significance. The proposed epidural recording approach showed good classification accuracy into sound perceived and not perceived when the best-performing electrodes were selected. Classifying different levels of sound stimulation accurately proved more challenging. At present, the methods explored in this study would not be sufficiently reliable to allow automated closed-loop control of CI parameters. However, our findings are an important initial contribution towards improving applicability of closed auditory loops and for next-generation automatic fitting approaches.

APA, Harvard, Vancouver, ISO, and other styles

6

Steven, David A., and Richard S. McLachlan. "Intracranial Telemetry Recording of Intractable Epilepsy at London Health Sciences." Canadian Journal of Neurological Sciences / Journal Canadien des Sciences Neurologiques 39, S6 (2012): S10—S13. http://dx.doi.org/10.1017/s0317167100018114.

Full text

Abstract:

Routine EEG telemetry using scalp electrode recordings is carried out in all patients being considered for epilepsy surgery. However this, along with other testing, may not yield sufficient information about the location of seizure onset to allow a decision regarding surgery to be made. Various methods have been developed to implant electrodes for chronic recording closer to the cortical surface from which seizures arise including the use of sphenoidal, foramen ovale, epidural peg, subdural and depth electrodes. This is a review of the last two techniques particularly as utilized at London Health Sciences Centre.

APA, Harvard, Vancouver, ISO, and other styles

7

Ross, Donald A., Thomas R. Henry, and Lawrence D. Dickinson. "A Percutaneous Epidural Screw Electrode for Intracranial Electroencephalogram Recordings." Neurosurgery 33, no. 2 (1993): 332–34. http://dx.doi.org/10.1227/00006123-199308000-00026.

Full text

APA, Harvard, Vancouver, ISO, and other styles

8

Ross, Donald A., Thomas R. Henry, and Lawrence D. Dickinson. "A Percutaneous Epidural Screw Electrode for Intracranial Electroencephalogram Recordings." Neurosurgery 33, no. 2 (1993): 332–34. http://dx.doi.org/10.1097/00006123-199308000-00026.

Full text

APA, Harvard, Vancouver, ISO, and other styles

9

Miyazawa, T., and K. A. Hossmann. "Methodological Requirements for Accurate Measurements of Brain and Body Temperature during Global Forebrain Ischemia of Rat." Journal of Cerebral Blood Flow & Metabolism 12, no. 5 (1992): 817–22. http://dx.doi.org/10.1038/jcbfm.1992.113.

Full text

Abstract:

The methodological requirements for accurate measurements of brain and body temperature during brain ischemia have been validated in Wistar rats submitted to 30 min of four-vessel occlusion. During ischemia, brains were exposed to three different temperature profiles: Spontaneous cooling from 36 to 31°C ( n = 10), constant hypothermia at 30°C ( n = 19), and constant normothermia at 36°C ( n = 21). Direct and indirect brain temperature recordings were carried out by placing fine thermocouples (200 μm diameter) into the striate nucleus, the temporal muscle, and the epidural space. Body temperature was measured with a flexible thermocouple inserted at various depths into the rectum. Accurate measurements of body temperature required insertion of the rectal probe to a depth of at least 6 cm; lesser insertion resulted in an underestimation of up to 6°C. Accurate estimates of brain temperature were obtained in all three experimental conditions by recording of the epidural temperature. The temperature in the temporal muscle, by contrast, differed from the brain temperature by up to 2°C, depending upon the experimental condition and the duration of ischemia. We therefore suggest that indirect measurements of brain temperature during ischemia are carried out in the epidural space in order to avoid misinterpretations of temperature-sensitive pathological changes.

APA, Harvard, Vancouver, ISO, and other styles

10

Gloor, Pierre. "Preoperative Electroencephalographic Investigation in Temporal Lobe Epilepsy: Extracranial and Intracranial Recordings." Canadian Journal of Neurological Sciences / Journal Canadien des Sciences Neurologiques 18, S4 (1991): 554–58. http://dx.doi.org/10.1017/s0317167100032686.

Full text

Abstract:

ABSTRACT:Preoperative EEG investigations of patients with temporal lobe seizures include extracranial interictal and ictal recordings during wakefulness and sleep, including long-term EEG and video-monitoring. Interictal epileptiform discharges when evaluated conservatively and in conjunction with other EEG and non-EEG localizing information, provide valuable guidance for the identification of the area to be resected, as do ictal recordings. When extracranial EEG features in conjunction with non-EEG data provide conflicting localizing information, intracranial recordings with stereotaxically implanted depth and epidural electrodes are used. Intracranial recordings must be designed to avoid biasing the exploration strategy in favor of one's preferred localizing hypothesis. Patients with evidence for bitemporal epileptogenic dysfunction in extracranial EEG recordings are suitable candidates for intracranial recordings. The majority of the patients explored in this manner show that all or more than 80% of their seizures arise from one temporal lobe. Excision of that lobe yields satisfactory results in a fair proportion of these patients. The number of satisfactory outcomes is, however, still somewhat less than in patients with unilateral temporal foci in extracranial EEG recordings.

APA, Harvard, Vancouver, ISO, and other styles

11

KUZNIECKY, RUBEN, EDWARD FAUGHT, and RICHARD MORAWETZ. "Surgical Treatment of Epilepsy: Initial Results Based Upon Epidural Electroencephalographic Recordings." Southern Medical Journal 83, no. 6 (1990): 637–39. http://dx.doi.org/10.1097/00007611-199006000-00010.

Full text

APA, Harvard, Vancouver, ISO, and other styles

12

Fischer, Benjamin, Andreas Schander, Andreas K. Kreiter, Walter Lang, and Detlef Wegener. "Visual epidural field potentials possess high functional specificity in single trials." Journal of Neurophysiology 122, no. 4 (2019): 1634–48. http://dx.doi.org/10.1152/jn.00510.2019.

Full text

Abstract:

Recordings of epidural field potentials (EFPs) allow neuronal activity to be acquired over a large region of cortical tissue with minimal invasiveness. Because electrodes are placed on top of the dura and do not enter the neuronal tissue, EFPs offer intriguing options for both clinical and basic science research. On the other hand, EFPs represent the integrated activity of larger neuronal populations and possess a higher trial-by-trial variability and a reduced signal-to-noise ratio due the additional barrier of the dura. It is thus unclear whether and to what extent EFPs have sufficient spatial selectivity to allow for conclusions about the underlying functional cortical architecture, and whether single EFP trials provide enough information on the short timescales relevant for many clinical and basic neuroscience purposes. We used the high spatial resolution of primary visual cortex to address these issues and investigated the extent to which very short EFP traces allow reliable decoding of spatial information. We briefly presented different visual objects at one of nine closely adjacent locations and recorded neuronal activity with a high-density epidural multielectrode array in three macaque monkeys. With the use of receiver operating characteristics (ROC) to identify the most informative data, machine-learning algorithms provided close-to-perfect classification rates for all 27 stimulus conditions. A binary classifier applying a simple max function on ROC-selected data further showed that single trials might be classified with 100% performance even without advanced offline classifiers. Thus, although highly variable, EFPs constitute an extremely valuable source of information and offer new perspectives for minimally invasive recording of large-scale networks. NEW & NOTEWORTHY Epidural field potential (EFP) recordings provide a minimally invasive approach to investigate large-scale neural networks, but little is known about whether they possess the required specificity for basic and clinical neuroscience. By making use of the spatial selectivity of primary visual cortex, we show that single-trial information can be decoded with close-to-perfect performance, even without using advanced classifiers and based on very few data. This labels EFPs as a highly attractive and widely usable signal.

APA, Harvard, Vancouver, ISO, and other styles

13

Vaira, Pasquale, Michela Camorcia, Tiziana Palladino, Matteo Velardo, and Giorgio Capogna. "Differentiating False Loss of Resistance from True Loss of Resistance While Performing the Epidural Block with the CompuFlo® Epidural Instrument." Anesthesiology Research and Practice 2019 (February 3, 2019): 1–4. http://dx.doi.org/10.1155/2019/5185901.

Full text

Abstract:

Background. The occurrence of false losses of resistance may be one of the reasons for inadequate or failed epidural block. A CompuFlo® epidural instrument has been introduced to measure the pressure of human tissues in real time at the orifice of a needle and has been used as a tool to identify the epidural space. The aim of this study was to investigate the sensitivity and the specificity of the ability of CompuFlo® to differentiate the false loss of resistance from the true loss of resistance encountered during the epidural space identification procedure. Method. We performed epidural block with the CompuFlo® epidural instrument in 120 healthy women who requested labor epidural analgesia. The epidural needle was considered to have reached the epidural space when an increase in pressure (accompanied by an increase in the pitch of the audible tone) was followed by a sudden and sustained drop in pressure for more than 5 seconds accompanied by a sudden decrease in the pitch of the audible tone, resulting in the formation of a low and stable pressure plateau. We evaluate the sensitivity, specificity, and positive and negative predictive values of the ability of CompuFlo® recordings to correctly identify the true LOR from the false LOR. Results. The drop in pressure associated with the epidural space identification was significantly greater than that recorded after the false loss of resistance (73% vs 33%) (P=0.000001). The sensitivity was 0.83, and the AUC was 0.82. Discussion. We have confirmed the ability of CompuFlo® to differentiate the false loss of resistance from the true loss of resistance and established its specificity and sensitivity. Conclusion. An easier identification of dubious losses of resistance during the epidural procedure is essential to reduce the number of epidural attempts and/or needle reinsertions with the potential of a reduced risk of accidental dural puncture especially in difficult cases or when the procedure is performed by trainees.

APA, Harvard, Vancouver, ISO, and other styles

14

Ding, Li, Aashvi Patel, Sneha Shankar, et al. "An Open-Source Mouse Chronic EEG Array System with High-Density MXene-Based Skull Surface Electrodes." eneuro 11, no. 2 (2024): ENEURO.0512–22.2023. http://dx.doi.org/10.1523/eneuro.0512-22.2023.

Full text

Abstract:

Electroencephalography (EEG) is an indispensable tool in epilepsy, sleep, and behavioral research. In rodents, EEG recordings are typically performed with metal electrodes that traverse the skull into the epidural space. In addition to requiring major surgery, intracranial EEG is difficult to perform for more than a few electrodes, is time-intensive, and confounds experiments studying traumatic brain injury. Here, we describe an open-source cost-effective refinement of this technique for chronic mouse EEG recording. Our alternative two-channel (EEG2) and sixteen-channel high-density EEG (HdEEG) arrays use electrodes made of the novel, flexible 2D nanomaterial titanium carbide (Ti3C2Tx) MXene. The MXene electrodes are placed on the surface of the intact skull and establish an electrical connection without conductive gel or paste. Fabrication and implantation times of MXene EEG electrodes are significantly shorter than the standard approach, and recorded resting baseline and epileptiform EEG waveforms are similar to those obtained with traditional epidural electrodes. Applying HdEEG to a mild traumatic brain injury (mTBI) model in mice of both sexes revealed that mTBI significantly increased spike–wave discharge (SWD) preictal network connectivity with frequencies of interest in the β-spectral band (12–30 Hz). These findings indicate that the fabrication of MXene electrode arrays is a cost-effective, efficient technology for multichannel EEG recording in mice that obviates the need for skull-penetrating surgery. Moreover, increased preictal β-frequency network connectivity may contribute to the development of early post-mTBI SWDs.

APA, Harvard, Vancouver, ISO, and other styles

15

Barolat-Romana, Giancarlo, Joel B. Myklebust, David C. Hemmy, Barbara Myklebust, and William Wenninger. "Immediate effects of spinal cord stimulation in spinal spasticity." Journal of Neurosurgery 62, no. 4 (1985): 558–62. http://dx.doi.org/10.3171/jns.1985.62.4.0558.

Full text

Abstract:

✓ Six patients with intractable spasms after spinal cord injury underwent implantation of an epidural spinal cord stimulation system. All the patients experienced good relief postoperatively. In three patients spinal cord stimulation consistently produced immediate inhibition of the spasms. This was evident within less than 1 minute of stimulation. Conversely, the spasms reappeared within less than 1 minute after cessation of the stimulation. The clinical observations were confirmed by polygraphic electromyographic recordings.

APA, Harvard, Vancouver, ISO, and other styles

16

Lundin, S. A., M. Elam, and B. G. Wallin. "INTRANEURAL RECORDINGS OF MUSCLE AND SKIN SYMPATHETIC ACTIVITY DURING EPIDURAL ANAESTHESIA IN MAN." Anesthesiology 69, no. 3A (1988): A335. http://dx.doi.org/10.1097/00000542-198809010-00334.

Full text

APA, Harvard, Vancouver, ISO, and other styles

17

Walter, J. S., J. S. Wheeler, C. J. Robinson, T. Khan, and R. D. Wurster. "Urethral responses to sacral stimulation in chronic spinal dog." American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 257, no. 2 (1989): R284—R291. http://dx.doi.org/10.1152/ajpregu.1989.257.2.r284.

Full text

Abstract:

Urethral activity was investigated in the awake chronic spinal-injured canine using urodynamic recordings, video cystofluoroscopy, and urethral pressure recordings without anesthesia. Bladder contractions and voiding were induced by electrical stimulation with epidural electrodes inserted into the sacral canal. Urethral pressure remained elevated during stimulation and for 1-3 s afterward. Poststimulation voiding occurred with three different patterns: 1) pulsatile voiding in which squirting of urine was associated with contractions in the membranous urethra; 2) "on and off" voiding in which pulsatile flow was interrupted for brief periods of time; and 3) steady-stream voiding in which nonpulsatile flow was followed by pulsatile flow. Viewing these voiding patterns with fluoroscopy indicated that the proximal membranous urethra was important in all of the patterns. We conclude that in the chronic spinal-injured canine the skeletal muscle within the membranous urethra (rhabdosphincter) is involved in responses to sacral stimulation and various voiding patterns.

APA, Harvard, Vancouver, ISO, and other styles

18

Jung, Fabienne, Klaas Enno Stephan, Heiko Backes, et al. "Mismatch Responses in the Awake Rat: Evidence from Epidural Recordings of Auditory Cortical Fields." PLoS ONE 8, no. 4 (2013): e63203. http://dx.doi.org/10.1371/journal.pone.0063203.

Full text

APA, Harvard, Vancouver, ISO, and other styles

19

Brucker-Hahn, Meagan, Scott Lempka, Megan Settell, et al. "ID: 319283 Preclinical Computational Modeling of Evoked Epidural Spinal Recordings During Spinal Cord Stimulation." Neuromodulation: Technology at the Neural Interface 27, no. 7 (2024): S273. http://dx.doi.org/10.1016/j.neurom.2024.06.477.

Full text

APA, Harvard, Vancouver, ISO, and other styles

20

Spüler, M., A. Walter, A. Ramos-Murguialday, et al. "Decoding of motor intentions from epidural ECoG recordings in severely paralyzed chronic stroke patients." Journal of Neural Engineering 11, no. 6 (2014): 066008. http://dx.doi.org/10.1088/1741-2560/11/6/066008.

Full text

APA, Harvard, Vancouver, ISO, and other styles

21

Tempelhoff, René, Paul A. Modica, Kerry L. Bernardo, and Isaac Edwards. "Fentanyl-induced electrocorticographic seizures in patients with complex partial epilepsy." Journal of Neurosurgery 77, no. 2 (1992): 201–8. http://dx.doi.org/10.3171/jns.1992.77.2.0201.

Full text

Abstract:

✓ Although electrical seizure activity in response to opioids such as fentanyl has been well described in animals, scalp electroencephalographic (EEG) recordings have failed to demonstrate epileptiform activity following narcotic administration in humans. The purpose of this study was to determine whether fentanyl is capable of evoking electrical seizure activity in patients with complex partial (temporal lobe) seizures. Nine patients were studied in whom recording electrode arrays had been placed in the bitemporal epidural space several days earlier to determine which temporal lobe gave rise to their seizures. The symptomatic temporal lobe was localized by correlating clinical and electrical seizure activity obtained during continuous simultaneous videotape and epidural EEG monitoring. In each patient, clinical seizures and electrical seizure activity were consistently demonstrated to arise unilaterally from one temporal lobe (four on the right, five on the left). During fentanyl induction of anesthesia in preparation for secondary craniotomy for anterior temporal lobectomy, eight of the nine patients exhibited electrical seizure activity at fentanyl doses ranging from 17.7 to 35.71 µg · kg−1 (mean 25.75 µg · kg−1). More importantly, four of these eight seizures occurred initially in the “healthy” temporal lobe contralateral to the surgically resected lobe from which the clinical seizures had been shown to arise. These findings indicate that, in patients with complex partial seizures, moderate doses of fentanyl can evoke electrical seizure activity. The results of this study could have important implications for neurosurgical centers where electrocorticography is used during surgery for the purpose of determining the extent of the resection.

APA, Harvard, Vancouver, ISO, and other styles

22

Vargas, Roth A. A., Marco Moscatelli, Marcos Vaz de Lima, et al. "Clinical Consequences of Incidental Durotomy during Full-Endoscopic Lumbar Decompression Surgery in Relation to Intraoperative Epidural Pressure Measurements." Journal of Personalized Medicine 13, no. 3 (2023): 381. http://dx.doi.org/10.3390/jpm13030381.

Full text

Abstract:

Background: Seizures, neurological deficits, bradycardia, and, in the worst cases, cardiac arrest may occur following incidental durotomy during routine lumbar endoscopy. Therefore, we set out to measure the intraoperative epidural pressure during lumbar endoscopic decompression surgery. Methods: We conducted a retrospective observational cohort study to obtain intraoperative epidural measurements with an epidural catheter-pressure transducer assembly through the spinal endoscope on 15 patients who underwent lumbar endoscopic decompression of symptomatic lumbar herniated discs and spinal stenosis. The endoscopic interlaminar technique was employed. Results: There were six (40.0%) female and nine (60.0%) male patients aged 49.0667 ± 11.31034, ranging from 36 to 72 years, with an average follow-up of 35.15 ± 12.48 months. Three of the fifteen patients had seizures with durotomy and one of these three had intracranial air on their postoperative brain CT. Another patient developed spinal headaches and diplopia on postoperative day one when her deteriorating neurological function was investigated with a brain computed tomography (CT) scan, showing an intraventricular hemorrhage consistent with a Fisher Grade IV subarachnoid hemorrhage. A CT angiogram did not show any abnormalities. Pressure recordings in the epidural space in nine patients ranged from 20 to 29 mm Hg with a mean of 24.33 mm Hg. Conclusion: Most incidental durotomies encountered during lumbar interlaminar endoscopy can be managed without formal repair and supportive care measures. The intradural spread of irrigation fluid and intraoperatively used drugs and air entrapment through an unrecognized durotomy should be suspected if patients deteriorate in the recovery room. Ascending paralysis may cause nausea, vomiting, upper and lower motor neuron symptoms, cranial nerve palsies, hypotension, bradycardia, and respiratory and cardiac arrest. The recovery team should be prepared to manage these complications.

APA, Harvard, Vancouver, ISO, and other styles

23

Capogna, Giorgio, Michela Camorcia, Cristiana Berritta, Mark Hochman, and Matteo Velardo. "Confirmation of Epidural Catheter Location by Epidural Pressure Waveform Recordings by the Compuflo<sup>® </sup> Cath-Checker System." Open Journal of Anesthesiology 10, no. 05 (2020): 171–78. http://dx.doi.org/10.4236/ojanes.2020.105015.

Full text

APA, Harvard, Vancouver, ISO, and other styles

24

Cioni, B., and M. Meglio. "Epidural Recordings of Electrical Events Produced in the Spinal Cord by Segmental, Ascending and Descending Volleys." Stereotactic and Functional Neurosurgery 49, no. 6 (1986): 315–26. http://dx.doi.org/10.1159/000100161.

Full text

APA, Harvard, Vancouver, ISO, and other styles

25

Aboghazleh, Refat, Ellen Parker, Lynn T. Yang, et al. "Brainstem and Cortical Spreading Depolarization in a Closed Head Injury Rat Model." International Journal of Molecular Sciences 22, no. 21 (2021): 11642. http://dx.doi.org/10.3390/ijms222111642.

Full text

Abstract:

Traumatic brain injury (TBI) is the leading cause of death in young individuals, and is a major health concern that often leads to long-lasting complications. However, the electrophysiological events that occur immediately after traumatic brain injury, and may underlie impact outcomes, have not been fully elucidated. To investigate the electrophysiological events that immediately follow traumatic brain injury, a weight-drop model of traumatic brain injury was used in rats pre-implanted with epidural and intracerebral electrodes. Electrophysiological (near-direct current) recordings and simultaneous alternating current recordings of brain activity were started within seconds following impact. Cortical spreading depolarization (SD) and SD-induced spreading depression occurred in approximately 50% of mild and severe impacts. SD was recorded within three minutes after injury in either one or both brain hemispheres. Electrographic seizures were rare. While both TBI- and electrically induced SDs resulted in elevated oxidative stress, TBI-exposed brains showed a reduced antioxidant defense. In severe TBI, brainstem SD could be recorded in addition to cortical SD, but this did not lead to the death of the animals. Severe impact, however, led to immediate death in 24% of animals, and was electrocorticographically characterized by non-spreading depression (NSD) of activity followed by terminal SD in both cortex and brainstem.

APA, Harvard, Vancouver, ISO, and other styles

26

Soldozy, Sauson, Steven Young, Jeyan S. Kumar, et al. "A systematic review of endovascular stent-electrode arrays, a minimally invasive approach to brain-machine interfaces." Neurosurgical Focus 49, no. 1 (2020): E3. http://dx.doi.org/10.3171/2020.4.focus20186.

Full text

Abstract:

OBJECTIVEThe goal of this study was to systematically review the feasibility and safety of minimally invasive neurovascular approaches to brain-machine interfaces (BMIs).METHODSA systematic literature review was performed using the PubMed database for studies published between 1986 and 2019. All studies assessing endovascular neural interfaces were included. Additional studies were selected based on review of references of selected articles and review articles.RESULTSOf the 53 total articles identified in the original literature search, 12 studies were ultimately selected. An additional 10 articles were included from other sources, resulting in a total of 22 studies included in this systematic review. This includes primarily preclinical studies comparing endovascular electrode recordings with subdural and epidural electrodes, as well as studies evaluating stent-electrode gauge and material type. In addition, several clinical studies are also included.CONCLUSIONSEndovascular stent-electrode arrays provide a minimally invasive approach to BMIs. Stent-electrode placement has been shown to be both efficacious and safe, although further data are necessary to draw comparisons between subdural and epidural electrode measurements given the heterogeneity of the studies included. Greater access to deep-seated brain regions is now more feasible with stent-electrode arrays; however, further validation is needed in large clinical trials to optimize this neural interface. This includes the determination of ideal electrode material type, venous versus arterial approaches, the feasibility of deep brain stimulation, and more streamlined computational decoding techniques.

APA, Harvard, Vancouver, ISO, and other styles

27

Nydahl, P. A., K. Axelsson, L. Philipson, P. Leissner, and P. G. Larsson. "Motor blockade and EMG recordings in epidural anaesthesia. A comparison between mepivacaine 2%, bupivacaine 0.5 % and etidocaine 1.5%." Acta Anaesthesiologica Scandinavica 33, no. 7 (1989): 597–604. http://dx.doi.org/10.1111/j.1399-6576.1989.tb02974.x.

Full text

APA, Harvard, Vancouver, ISO, and other styles

28

Koehler, R. Besser, P. Stoeter, P., J. "Scalp, basal epidural and intravascular far-field recordings after median nerve stimulation: evidence for a separate N18a potential." Somatosensory & Motor Research 17, no. 3 (2000): 239–43. http://dx.doi.org/10.1080/08990220050117592.

Full text

APA, Harvard, Vancouver, ISO, and other styles

29

Iduh, Carolyn, Anwara Khan, Prasanth Chalamalasetty, Tuba Shiwani, Lily Nguyen, and Faisal R. Jahangiri. "Benefits and Risks of Intraoperative Neuromonitoring for Intramedullary Spinal Cord Tumors. A Technical Report." Journal of Neurophysiological Monitoring 2, no. 1 (2024): 44–54. https://doi.org/10.5281/zenodo.10573532.

Full text

Abstract:

Intramedullary spinal cord tumors (IMSCT) are a rare condition that can have adverse effects on both the sensory and motor tracts, as well as the gray and white matter of the spinal cord. One type of IMSCT, known as ependymomas, is typically seen in adults, and is characterized by an enhancing mass with clear borders extending outward from the central canal's ependymal lining. In this study, over 800 patients have undergone intramedullary spinal cord tumor surgeries with intraoperative neurophysiological monitoring (IONM), and the majority have successfully overcome any postoperative deficits.   Multimodal IONM techniques, such as Somatosensory Evoked Potentials (SSEPs), Motor Evoked Potentials (MEPs), Epidural recordings (D-waves), Electromyography (EMG), Bulbocavernosus Reflex (BCR), and Train of Four (TOF), were used to monitor the procedures. While intramedullary spinal tumors can be challenging to treat, early surgery can lead to better outcomes. Intraoperative modalities like D-waves and MEPs have shown promise in reducing neurological outcomes, but more research is needed to understand their effectiveness fully.

APA, Harvard, Vancouver, ISO, and other styles

30

Broseta, Jaime, José Barberá, J. A. de Vera, et al. "Spinal cord stimulation in peripheral arterial disease." Journal of Neurosurgery 64, no. 1 (1986): 71–80. http://dx.doi.org/10.3171/jns.1986.64.1.0071.

Full text

Abstract:

✓ Percutaneous epidural Stimulation of the low thoracic spinal cord was carried out in 41 patients with pain from peripheral arterial disease of the lower limbs. Results are reported relating to pain, claudication distance, peripheral blood flow, and trophic lesion changes. Following a trial period of stimulation, 37 patients had stimulators permanently implanted. After a mean poststimulation follow-up period of 25 months, substantial pain relief (75% to 100%) was obtained in 29 cases; claudication distance significantly increased in 15 cases; Doppler ultrasound recordings of lower-limb distal arteries showed a tendency toward normalization of pulse-wave morphology, with increase of amplitude in 12 of the 23 patients studied; a rise in skin temperature was also detected by thermography. Distal arterial blood pressure remained unchanged with stimulation. Ischemic cutaneous trophic lesions of less than 3 sq cm healed, but gangrenous conditions were not benefited. A placebo effect or the natural history of the disease can be excluded as the reason for these improvements. It is concluded that spinal cord stimulation is a valid alternative treatment for moderate peripheral arterial disorders when direct arterial surgery is not possible or has been unsuccessful.

APA, Harvard, Vancouver, ISO, and other styles

31

Telenczuk, Bartosz, Stuart N. Baker, Andreas V. M. Herz, and Gabriel Curio. "High-frequency EEG covaries with spike burst patterns detected in cortical neurons." Journal of Neurophysiology 105, no. 6 (2011): 2951–59. http://dx.doi.org/10.1152/jn.00327.2010.

Full text

Abstract:

Invasive microelectrode recordings measure neuronal spikes, which are commonly considered inaccessible through standard surface electroencephalogram (EEG). Yet high-frequency EEG potentials (hf-EEG, f > 400 Hz) found in somatosensory evoked potentials of primates may reflect the mean population spike responses of coactivated cortical neurons. Since cortical responses to electrical nerve stimulation vary strongly from trial to trial, we investigated whether the hf-EEG signal can also echo single-trial variability observed at the single-unit level. We recorded extracellular single-unit activity in the primary somatosensory cortex of behaving macaque monkeys and identified variable spike burst responses following peripheral stimulation. Each of these responses was classified according to the timing of its spike constituents, conforming to one of a discrete set of spike patterns. We here show that these spike patterns are accompanied by variations in the concomitant epidural hf-EEG. These variations cannot be explained by fluctuating stimulus efficacy, suggesting that they were generated within the thalamocortical network. As high-frequency EEG signals can also be reliably recorded from the scalp of human subjects, they may provide a noninvasive window on fluctuating cortical spike activity in humans.

APA, Harvard, Vancouver, ISO, and other styles

32

Yu, Gene J., Federico Ranieri, Vincenzo Di Lazzaro, Marc A. Sommer, Angel V. Peterchev, and Warren M. Grill. "Circuits and mechanisms for TMS-induced corticospinal waves: Connecting sensitivity analysis to the network graph." PLOS Computational Biology 20, no. 12 (2024): e1012640. https://doi.org/10.1371/journal.pcbi.1012640.

Full text

Abstract:

Transcranial magnetic stimulation (TMS) is a non-invasive, FDA-cleared treatment for neuropsychiatric disorders with broad potential for new applications, but the neural circuits that are engaged during TMS are still poorly understood. Recordings of neural activity from the corticospinal tract provide a direct readout of the response of motor cortex to TMS, and therefore a new opportunity to model neural circuit dynamics. The study goal was to use epidural recordings from the cervical spine of human subjects to develop a computational model of a motor cortical macrocolumn through which the mechanisms underlying the response to TMS, including direct and indirect waves, could be investigated. An in-depth sensitivity analysis was conducted to identify important pathways, and machine learning was used to identify common circuit features among these pathways. Sensitivity analysis identified neuron types that preferentially contributed to single corticospinal waves. Single wave preference could be predicted using the average connection probability of all possible paths between the activated neuron type and L5 pyramidal tract neurons (PTNs). For these activations, the total conduction delay of the shortest path to L5 PTNs determined the latency of the corticospinal wave. Finally, there were multiple neuron type activations that could preferentially modulate a particular corticospinal wave. The results support the hypothesis that different pathways of circuit activation contribute to different corticospinal waves with participation of both excitatory and inhibitory neurons. Moreover, activation of both afferents to the motor cortex as well as specific neuron types within the motor cortex initiated different I-waves, and the results were interpreted to propose the cortical origins of afferents that may give rise to certain I-waves. The methodology provides a workflow for performing computationally tractable sensitivity analyses on complex models and relating the results to the network structure to both identify and understand mechanisms underlying the response to acute stimulation.

APA, Harvard, Vancouver, ISO, and other styles

33

Hurlbert, R. John, Charles H. Tator, Michael G. Fehlings, Greg Niznik, and R. Dean Linden. "Evoked potentials from direct cerebellar stimulation for monitoring of the rodent spinal cord." Journal of Neurosurgery 76, no. 2 (1992): 280–91. http://dx.doi.org/10.3171/jns.1992.76.2.0280.

Full text

Abstract:

✓ Although the assessment of spinal cord function by electrophysiological techniques has become important in both clinical and research environments, current monitoring methods do not completely evaluate all tracts in the spinal cord. Somatosensory and motor evoked potentials primarily reflect dorsal column and pyramidal tract integrity, respectively, but do not directly assess the status of the ventral funiculus. The present study was undertaken to evaluate the use of evoked potentials, elicited by direct cerebellar stimulation, in monitoring the ventral component of the rodent spinal cord. Twenty-nine rats underwent epidural anodal stimulation directly over the cerebellar cortex, with recording of evoked responses from the lower thoracic spinal cord, both sciatic nerves, and/or both gastrocnemius muscles. Stimulation parameters were varied to establish normative characteristics. The pathways conducting these “posterior fossa evoked potentials” were determined after creation of various lesions of the cervical spinal cord. The evoked potential recorded from the thoracic spinal cord consisted of five positive (P1 to P5) and five negative (N1 to N5) peaks. The average conduction velocity (± standard deviation) of the earliest wave (P1) was 53 ± 4 m/sec, with a latency of 1.24 ± 0.10 msec. The other components followed within 4 msec from stimulus onset. Unilateral cerebellar stimulation resulted in bilateral sciatic nerve and gastrocnemius muscle responses; there were no significant differences (p > 0.05) in the thresholds, amplitudes, or latencies of these responses elicited by right- versus left-sided stimulation. Recordings performed following creation of selective lesions of the cervical cord indicated that the thoracic response was carried primarily in the ventral funiculus while the sciatic and gastrocnemius responses were mediated through the dorsal half of the spinal cord. It is concluded that the posterior fossa evoked potential has research value as a method of monitoring pathways within the ventral spinal cord of the rat, and should be useful in the study of spinal cord injury.

APA, Harvard, Vancouver, ISO, and other styles

34

Pirotte, Benoit, Philippe Voordecker, Freddy Joffroy, et al. "The Zeiss-MKM system for frameless image-guided approach in epidural motor cortex stimulation for central neuropathic pain." Neurosurgical Focus 11, no. 3 (2001): 1–6. http://dx.doi.org/10.3171/foc.2001.11.3.4.

Full text

Abstract:

Object Twelve patients (seven female, and five male, mean age 55.6 years) suffering from refractory central (ischemic/traumatic [eight cases]) and neuropathic pain (trigeminal neuropathy [four cases]) underwent surgery for the implantation of an epidural motor cortex stimulation (MCS) device in which the authors used a frameless neuronavigation system, the Zeiss-MKM microscope. Methods The authors assessed the spatial accuracy of the neuronavigation system and its potential contribution to improve the quality of targeting pain. In these patients, the positions of the central sulcus, defined by stereotactic magnetic resonance MR imaging, intraoperative somatosensory evoked potentials (SSEPs) and subdural visual verification, were correlated into the stereotactic neuronavigation planning procedure. The mean spatial accuracy of distance between (MR) imaging–defined and actual central sulcus was 2.4 mm (range 5–10 mm). The intraoperative SSEP-defined central sulcus was close to that defined by MR imaging (mean distance 6.4 mm). Although very precise, intra-operative SSEP recordings were impaired by artifacts and wave attenuation in six of the 12 patients. Stereotactic correlations between anatomical and functional data in the navigation system corrected final targeting in 10 of 12 cases. Pain relief was obtained in eight patients. Indeed, inappropriate targeting probably explains the reported variable success rate of MCS and certainly underestimates the actual efficacy. Conclusions Since intraoperative SSEP monitoring has, for many years, been considered the standard procedure to approach motor target, the development of an accurate stereotactic image guidance system could help to increase the efficacy of MCS on the alleviation of pain. The excellent spatial accuracy provided by the Zeiss-MKM navigation system allows precise data correlations that represent a remarkable means to validate functional MR imaging as an alternative to SSEP. The authors believe that developing stereotactic image guidance with such a navigation system could improve the success rate of MCS.

APA, Harvard, Vancouver, ISO, and other styles

35

Miller, Jimmy D., Jogi Pattisapu, Dudley F. Peeler, and Andrew D. Parent. "Intracranial pressure monitoring by flaccid-cuff catheter in an animal model." Journal of Neurosurgery 63, no. 2 (1985): 242–45. http://dx.doi.org/10.3171/jns.1985.63.2.0242.

Full text

Abstract:

✓ Several methods of monitoring intracranial pressure (ICP) are in current use, each with its own advantages and disadvantages. The intraventricular line has been most useful because of the ability to withdraw cerebrospinal fluid to assist in control of elevated ICP. However, masses within the brain or generalized increased ICP may compress the lateral ventricle, making insertion of the catheter difficult or impossible. The intracerebral wick records hydrostatic changes too slowly to be used clinically. Swollen cerebral tissue may occlude the subarachnoid bolt thereby dampening the recorded pressure, and epidural monitors may give falsely high recordings because of irregularities of dura or bone. The authors have developed a flaccid-cuff catheter which has proven in animals to be an effective ICP monitor. There are several advantages, such as easy insertion into the centrum semiovale, rapid response to acute pressure changes, and continued sensitivity for periods of up to 3 weeks. The flaccid catheter cuff has no tension so that the pressure across the membrane is equal to zero, simplifying calibration. This type of cuff is necessary for maximum sensitivity to interstitial, brain-tissue, and gross ICP changes. The flaccid-cuff catheter may prove to be useful in a variety of situations such as after closed head trauma or intracranial surgery to assess elevated ICP caused by edema or evolving hematoma.

APA, Harvard, Vancouver, ISO, and other styles

36

Moly, Alexandre, Thomas Costecalde, Félix Martel, et al. "An adaptive closed-loop ECoG decoder for long-term and stable bimanual control of an exoskeleton by a tetraplegic." Journal of Neural Engineering 19, no. 2 (2022): 026021. http://dx.doi.org/10.1088/1741-2552/ac59a0.

Full text

Abstract:

Abstract Objective. The article aims at addressing 2 challenges to step motor brain-computer interface (BCI) out of laboratories: asynchronous control of complex bimanual effectors with large numbers of degrees of freedom, using chronic and safe recorders, and the decoding performance stability over time without frequent decoder recalibration. Approach. Closed-loop adaptive/incremental decoder training is one strategy to create a model stable over time. Adaptive decoders update their parameters with new incoming data, optimizing the model parameters in real time. It allows cross-session training with multiple recording conditions during closed loop BCI experiments. In the article, an adaptive tensor-based recursive exponentially weighted Markov-switching multi-linear model (REW-MSLM) decoder is proposed. REW-MSLM uses a mixture of expert (ME) architecture, mixing or switching independent decoders (experts) according to the probability estimated by a ‘gating’ model. A Hidden Markov model approach is employed as gating model to improve the decoding robustness and to provide strong idle state support. The ME architecture fits the multi-limb paradigm associating an expert to a particular limb or action. Main results. Asynchronous control of an exoskeleton by a tetraplegic patient using a chronically implanted epidural electrocorticography (EpiCoG) recorder is reported. The stable over a period of six months (without decoder recalibration) eight-dimensional alternative bimanual control of the exoskeleton and its virtual avatar is demonstrated. Significance. Based on the long-term (>36 months) chronic bilateral EpiCoG recordings in a tetraplegic (ClinicalTrials.gov, NCT02550522), we addressed the poorly explored field of asynchronous bimanual BCI. The new decoder was designed to meet to several challenges: the high-dimensional control of a complex effector in experiments closer to real-world behavior (point-to-point pursuit versus conventional center-out tasks), with the ability of the BCI system to act as a stand-alone device switching between idle and control states, and a stable performance over a long period of time without decoder recalibration.

APA, Harvard, Vancouver, ISO, and other styles

37

Bauernfeind, G., M. J. Teschner, S. C. Wriessnegger, A. Büchner, T. Lenarz, and S. Haumann. "Towards single-trial classification of invasively recorded auditory evoked potentials in cochlear implant users." Journal of Neural Engineering 19 (June 5, 2022): 1–16. https://doi.org/10.1088/1741-2552/ac572d.

Full text

APA, Harvard, Vancouver, ISO, and other styles

38

Fransen, Anne M. M., George Dimitriadis, Freek van Ede та Eric Maris. "Distinct α- and β-band rhythms over rat somatosensory cortex with similar properties as in humans". Journal of Neurophysiology 115, № 6 (2016): 3030–44. http://dx.doi.org/10.1152/jn.00507.2015.

Full text

Abstract:

We demonstrate distinct α- (7–14 Hz) and β-band (15–30 Hz) rhythms in rat somatosensory cortex in vivo using epidural electrocorticography recordings. Moreover, we show in rats that a genuine β-rhythm coexists alongside β-activity that reflects the second harmonic of the arch-shaped somatosensory α-rhythm. This demonstration of a genuine somatosensory β-rhythm depends on a novel quantification of neuronal oscillations that is based on their rhythmic nature: lagged coherence. Using lagged coherence, we provide two lines of evidence that this somatosensory β-rhythm is distinct from the second harmonic of the arch-shaped α-rhythm. The first is based on the rhythms' spatial properties: the α- and β-rhythms are demonstrated to have significantly different topographies. The second is based on the rhythms' temporal properties: the lagged phase-phase coupling between the α- and β-rhythms is demonstrated to be significantly less than would be expected if both reflected a single underlying nonsinusoidal rhythm. Finally, we demonstrate that 1) the lagged coherence spectrum is consistent between signals from rat and human somatosensory cortex; and 2) a tactile stimulus has the same effect on the somatosensory α- and β-rhythms in both rats and humans, namely suppressing them. Thus we not only provide evidence for the existence of genuine α- and β-rhythms in rat somatosensory cortex, but also for their homology to the primate sensorimotor α- and β-rhythms.

APA, Harvard, Vancouver, ISO, and other styles

39

Olschewski, Andrea, Gunter Hempelmann, Werner Vogel, and Boris V. Safronov. "Suppression of Potassium Conductance by Droperidol Has Influence on Excitability of Spinal Sensory Neurons." Anesthesiology 94, no. 2 (2001): 280–89. http://dx.doi.org/10.1097/00000542-200102000-00018.

Full text

Abstract:

Background During spinal and epidural anesthesia with opioids, droperidol is added to prevent nausea and vomiting. The mechanisms of its action on spinal sensory neurons are not well understood. It was previously shown that droperidol selectively blocks a fast component of the Na+ current. The authors studied the action of droperidol on voltage-gated K+ channels and its effect on membrane excitability in spinal dorsal horn neurons of the rat. Methods Using a combination of the patch-clamp technique and the "entire soma isolation" method, the action of droperidol on fast-inactivating A-type and delayed-rectifier K+ channels was investigated. Current-clamp recordings from intact sensory neurons in spinal cord slices were performed to study the functional meaning of K+ channel block for neuronal excitability. Results Droperidol blocked delayed-rectifier K+ currents in isolated somata of dorsal horn neurons with a half-maximum inhibiting concentration of 20.6 microm. The A-type K+ current was insensitive to up to 100 microm droperidol. At droperidol concentrations insufficient for suppression of an action potential, the block of delayed-rectifier K+ channels led to an increase in action potential duration and, as a consequence, to lowering of the discharge frequency in the neuron. Conclusions Droperidol blocks delayed-rectifier K+ channels in a concentration range close to that for suppression of Na+ channels. The block of delayed-rectifier K+ channels by droperidol enhances the suppression of activity in spinal sensory neurons at drug concentrations insufficient for complete conduction block.

APA, Harvard, Vancouver, ISO, and other styles

40

Kellinghaus, Christoph, Gabriel Möddel, Hiroshi Shigeto, et al. "Dissociation between in vitro and in vivo epileptogenicity in a rat model of cortical dysplasia." Epileptic Disorders 9, no. 1 (2007): 11–19. http://dx.doi.org/10.1684/epd.2007.0061.

Full text

Abstract:

ABSTRACT Objective. Malformations of cortical development are frequent causes of human refractory epilepsy. The freeze‐lesion model in rats shows histopathological features similar to those found in human polymicrogyria. Previous studies reported in vitro hyperexcitability in this model, but in vivo epileptogenicity has not been confirmed. Methods Neocortical freeze lesions were induced in Sprague‐Dawley rat pups (n = 10) on postnatal day 0 or 1 (P0/P1). Sham‐operated animals served as controls (n = 10). On P60, animals were implanted with epidural electrodes for long‐term video‐EEG monitoring (4 weeks). The threshold for pentylenetetrazolinduced seizures was determined. Animals were sacrificed and brain sections processed for histological staining and in vitro electrophysiological recordings. Epileptiform field potential repetition rate, amplitude and integral were compared between slices containing a cortical freeze lesion, and slices from sham‐operated rats. Results No interictal spikes and no electrographic or clinical seizures occurred in either group. The median threshold for pentylenetetrazol‐induced seizures was 60 mg/kg for lesioned, and 45 mg/kg for control animals (difference not significant). No spontaneous epileptiform field potentials were recorded from either freeze‐lesion or control slices bathed in normal, artificial cerebrospinal fluid (ACSF). Upon omission of Mg 2+ from the bath, epileptiform field potentials were elicited that showed a significantly higher burst integral in the freeze lesion slices compared to control slices. Conclusion Neocortical freeze lesions induced in newborn rat pups show histological characteristics reminiscent of human cortical dysplasia. Brain slices containing neocortical freeze lesions display hyperexcitability in vitro , but the same lesion does not appear to show spontaneous epileptogenicity in vivo .

APA, Harvard, Vancouver, ISO, and other styles

41

Nita, Dragos A., Sampsa Vanhatalo, Frantz-Daniel Lafortune, Juha Voipio, Kai Kaila, and Florin Amzica. "Nonneuronal Origin of CO2-Related DC EEG Shifts: An In Vivo Study in the Cat." Journal of Neurophysiology 92, no. 2 (2004): 1011–22. http://dx.doi.org/10.1152/jn.00110.2004.

Full text

Abstract:

We studied the mechanisms underlying CO2-dependent DC potential shifts, using epicranial, epidural, epicortical, intraventricular, and intraparenchymal (intraneuronal, intraglial, and field) recordings in ketamine–xylazine-anesthetized cats. DC shifts were elicited by changes in artificial ventilation, causing end-tidal CO2 variations within a 2–5% range. Hypercapnia was consistently associated with negative scalp DC shifts (average shift −284.4 μV/CO2%, range −216 to −324 μV/CO2%), whereas hypocapnia induced positive scalp DC shifts (average shift 307.8 μV/CO2%, range 234 to 342 μV/CO2%) in all electrodes referenced versus the nasium bone. The former condition markedly increased intracranial pressure (ICP), whereas the latter only slightly reduced ICP. Breakdown of the blood–brain barrier (BBB) resulted in a positive DC shift and drastically reduced subsequent DC responses to hypo-/hypercapnia. Thiopental and isoflurane also elicited a dose-dependent positive DC shift and, at higher doses, hypo-/hypercapnia responses displayed reverted polarity. As to the possible implication of neurons in the production of DC shifts, no polarity reversal was recorded between scalp, various intracortical layers, and deep brain structures. Moreover, the membrane potential of neurons and glia did not show either significant or systematic variations in association with the scalp-recorded CO2-dependent DC shifts. Pathological activities of neurons during spike-wave seizures produced DC shifts of significantly smaller amplitude than those generated by hyper-/hypocapnia. DC shifts were still elicited when neuronal circuits were silent during anesthesia-induced burst-suppression patterns. We suggest that potentials generated by the BBB are the major source of epicortical/cranial DC shifts recorded under conditions affecting brain pH and/or cerebral blood flow.

APA, Harvard, Vancouver, ISO, and other styles

42

Sitnikova, Evgenia, Dmitrii Perevozniuk, Elizaveta Rutskova, Shukhrat Uzakov, and Viktor A. Korshunov. "Reduction of Hippocampal High-Frequency Activity in Wag/Rij Rats with a Genetic Predisposition to Absence Epilepsy." Diagnostics 12, no. 11 (2022): 2798. http://dx.doi.org/10.3390/diagnostics12112798.

Full text

Abstract:

In temporal lobe epilepsy, high frequency oscillations serve as electroencephalographic (EEG) markers of epileptic hippocampal tissue. In contrast, absence epilepsy and other idiopathic epilepsies are known to result from thalamo-cortical abnormalities, with the hippocampus involvement considered to be only indirect. We aimed to uncover the role of the hippocampus in absence epilepsy using a genetic rat model of absence epilepsy (WAG/Rij rats), in which spike-wave discharges (SWDs) appear spontaneously in cortical EEG. We performed simultaneous recordings of local field potential from the hippocampal dentate gyrus using pairs of depth electrodes and epidural cortical EEG in freely moving rats. Hippocampal ripples (100–200 Hz) and high frequency oscillations (HFO, 50–70 Hz) were detected using GUI RIPPLELAB in MatLab (Navarrete et al., 2016). Based on the dynamics of hippocampal ripples, SWDs were divided into three clusters, which might represent different seizure types in reference to the involvement of hippocampal processes. This might underlie impairment of hippocampus-related cognitive processes in some patients with absence epilepsy. A significant reduction to nearly zero-ripple-density was found 4–8 s prior to SWD onset and during 4 s immediately after SWD onset. It follows that hippocampal ripples were not just passively blocked by the onset of SWDs, but they were affected by spike-wave seizure initiation mechanisms. Hippocampal HFO were reduced during the preictal, ictal and postictal periods in comparison to the baseline. Therefore, hippocampal HFO seemed to be blocked with spike-wave seizures. All together, this might underlie impairment of hippocampus-related cognitive processes in some patients with absence epilepsy. Further investigation of processes underlying SWD-related reduction of hippocampal ripples and HFO oscillations may help to predict epileptic attacks and explain cognitive comorbidities in patients with absence epilepsy.

APA, Harvard, Vancouver, ISO, and other styles

43

Seko, Kei, Tadahiko Imai, Kazuki Mori, Kazunori Shirasu, Teruji Mukai, and Tetsuji Fujiwara. "PS-38-5 Spinal cord conduction study with comparatively non-invasive and reliable methods — scrutiny of the past techniques: skin surface electrode, needle electrode and epidural electrode recordings, magnetic and electric stimulation." Electroencephalography and Clinical Neurophysiology/Electromyography and Motor Control 97, no. 4 (1995): S181. http://dx.doi.org/10.1016/0924-980x(95)93100-8.

Full text

APA, Harvard, Vancouver, ISO, and other styles

44

Howard-Quijano, Kimberly, Tatsuo Takamiya, Erica A. Dale, et al. "Spinal cord stimulation reduces ventricular arrhythmias during acute ischemia by attenuation of regional myocardial excitability." American Journal of Physiology-Heart and Circulatory Physiology 313, no. 2 (2017): H421—H431. http://dx.doi.org/10.1152/ajpheart.00129.2017.

Full text

Abstract:

Myocardial ischemia creates autonomic nervous system imbalance and can trigger cardiac arrhythmias. We hypothesized that neuromodulation by spinal cord stimulation (SCS) will attenuate local cardiac sympathoexcitation from ischemia-induced increases in afferent signaling, reduce ventricular arrhythmias, and improve myocardial function during acute ischemia. Yorkshire pigs ( n = 20) were randomized to SCS (50 Hz at 200-μs duration, current 90% motor threshold) or sham operation (sham) for 30 min before ischemia. A four-pole SCS lead was placed percutaneously in the epidural space (T1–T4), and a 56-electrode mesh was placed over the heart for high-resolution electrophysiological recordings, including activation recovery intervals (ARIs), activation time, repolarization time, and dispersion of repolarization. Electrophysiological and hemodynamic measures were recorded at baseline, after SCS/sham, during acute ischemia (300-s coronary artery ligation), and throughout reperfusion. SCS 1) reduced sympathoexcitation-induced ARI and repolarization time shortening in the ischemic myocardium; 2) attenuated increases in the dispersion of repolarization; 3) reduced ventricular tachyarrythmias [nonsustained ventricular tachycardias: 24 events (3 sham animals) vs. 1 event (1 SCS animal), P < 0.001]; and 4) improved myocardial function (dP/d t from baseline to ischemia: 1,814 ± 213 to 1,596 ± 282 mmHg/s in sham vs. 1,422 ± 299 to 1,380 ± 299 mmHg/s in SCS, P < 0.01). There was no change in ventricular electrophysiology during baseline conditions without myocardial stress or in the nonischemic myocardium. In conclusion, in a porcine model of acute ventricular ischemia, SCS reduced regional myocardial sympathoexcitation, decreased ventricular arrhythmias, and improved myocardial function. SCS decreased sympathetic nerve activation locally in the ischemic myocardium with no effect observed in the normal myocardium, thus providing mechanistic insights into the antiarrhythmic and myocardial protective effects of SCS. NEW & NOTEWORTHY In a porcine model of ventricular ischemia, spinal cord stimulation decreased sympathetic nerve activation regionally in ischemic myocardium with no effect on normal myocardium, demonstrating that the antiarrhythmic effects of spinal cord stimulation are likely due to attenuation of local sympathoexcitation in the ischemic myocardium and not changes in global myocardial electrophysiology.

APA, Harvard, Vancouver, ISO, and other styles

45

Nainzadeh, N., M. Neuwirth, R. Bernstein, and M. E. Lane. "Accuracy of intraoperative epidural recording of evoked potentials, using a modified epidural electrode." Electroencephalography and Clinical Neurophysiology 61, no. 3 (1985): S28. http://dx.doi.org/10.1016/0013-4694(85)90142-7.

Full text

APA, Harvard, Vancouver, ISO, and other styles

46

Habib, Ahmed, Hansen Deng, N. U. Farrukh Hameed, Scott Kulich, and Pascal Zinn. "Microsurgery resection of giant cervicothoracic spinal ependymoma: Two-dimensional operative video." Surgical Neurology International 15 (July 12, 2024): 237. http://dx.doi.org/10.25259/sni_317_2024.

Full text

Abstract:

Background: Ependymomas, rare glial brain tumors, account for <5% of all brain tumors. Interestingly, over 60% of ependymomas occur in the spinal cord of adults, including those originating from the filum terminale, while the rest are found within the brain. The World Health Organization (WHO) categorizes ependymomas into three grades: subependymomas and myxopapillary ependymomas ([MEPNs]; WHO grade I), classic ependymomas (WHO grade II), and anaplastic ependymomas (WHO grade III). Spinal ependymomas generally exhibit a more favorable prognosis compared to their intracranial counterparts and are primarily treated through gross total resection, which is considered the most effective surgical approach. As such, they are recognized as a distinct clinical entity that demands tailored management strategies. MEPNs, which constitute 13% of ependymomas, typically occur in the cauda equina and sometimes extend into the conus medullaris. Most other spinal ependymomas are of the classic type and predominantly arise in the cervical and thoracic regions of the spine. The mean age at diagnosis is 45 years of age. While prognosis varies based on molecular subtypes, complete resection is associated with improved survival. Case Description: Here, we demonstrate the technical nuances to safely achieve gross total resection of a giant spinal ependymoma in a 29-year-old female with a medical history notable for sept-optic dysplasia, and panhypopituitarism. The patient presented with progressive neck pain, upper and lower extremity weakness, and numbness for 1 year. On physical examination, she demonstrated mild weakness in her left arm. The preoperative magnetic resonance imaging revealed a cervicothoracic intramedullary mass extending from C4 to T2 with an associated syrinx at C4. Under intraoperative neural monitoring (somatosensory evoked potentials, motor-evoked potentials, and epidural direct wave recordings), the patient underwent a C4 – T2 laminectomy. In addition, spinal ultrasonography helped differentiate solid tumor mass from syrinx formation, thus guiding the focus and extent of the decompression . Conclusion: Gross total resection was achieved; at 18 postoperative months, the patient had mild residual motor deficit. The pathological evaluation revealed a WHO grade II ependymoma. Subsequent sequential enhanced MR studies at 3, 6, and 12 months confirmed no tumor recurrence.

APA, Harvard, Vancouver, ISO, and other styles

47

Poca, Maria A., Diego Lopez-Bermeo, Paola Cano, et al. "Continuous Intracranial Pressure Monitoring in Children with ‘Benign’ External Hydrocephalus." Journal of Clinical Medicine 14, no. 9 (2025): 3042. https://doi.org/10.3390/jcm14093042.

Full text

Abstract:

Background/Objectives: This study aimed to evaluate the results of continuous intracranial pressure (ICP) monitoring in children with macrocephaly or rapidly increasing head circumference (HC) diagnosed as benign external hydrocephalus (BEH). Here, we report the absolute ICP measurements, ICP pulsatility, and slow ICP waves after at least 48 h of continuous monitoring in a cohort of 36 children diagnosed with BEH. Methods: A prospective study of continuous ICP monitoring was performed in 36 consecutive children with macrocephaly (HC above the 97.5th percentile) or rapidly increasing HC (at least crossing two percentile curves), diagnosed with BEH (22 boys and 14 girls with a mean age of 23.6 ± 13.3 months, minimum: 6, maximum 65), using an epidural sensor. For the first four children in the study, hard copies of the ICP values were obtained using an analog recorder. Starting from the fifth patient, the ICP signal was sampled at 200 Hz and stored on a computer using a computer-based data acquisition and analysis system (LabChart v8.1 software). Results: Clinical signs or symptoms were identified in 20 patients (55.6%). Delayed motor or language development was noted in 18 (50%) and 20 (55.6%) patients, respectively. In 13 patients, the enlargement of the subarachnoid spaces was found to be associated with an additional condition. The median of mean ICP values for the entire cohort was 17 mmHg, with a minimum of 6.7 mmHg and a maximum of 29 mmHg. All patients exhibited a percentage of B waves exceeding 20% during the night, with a median value of 47.4% (min: 23.2, max: 75). Three children had nocturnal plateau waves. At night, regular ICP recordings alternated with periods of significant increases in ICP, often exceeding 10 mmHg above baseline values. High-amplitude B waves were noted during these episodes, and the amplitude of the cardiac waveform at the peak of the B waves was consistently greater than 5 mmHg, displaying an abnormal morphology (P2 > P1). A ventriculoperitoneal shunt was implanted in 30 of the 36 patients. Conclusions: Patients with BEH may present significant abnormalities in ICP. Monitoring this variable in certain cases can assist in determining the necessity for surgical treatment.

APA, Harvard, Vancouver, ISO, and other styles

48

Sachs, H. G., F. Gekeler, H. Schwahn, et al. "Implantation of Stimulation Electrodes in the Subretinal Space to Demonstrate Cortical Responses in Yucatan Minipig in the Course of Visual Prosthesis Development." European Journal of Ophthalmology 15, no. 4 (2005): 493–99. http://dx.doi.org/10.1177/112067210501500413.

Full text

Abstract:

Purpose During the course of the development of visual prostheses, subretinal stimulation films were implanted in micropigs in order to prove the feasibility of subretinal electrical stimulation with subsequent cortical response. One aim was to demonstrate that epidural recording of visual evoked potentials is possible in the micropig. Methods Film-bound stimulation electrode arrays were placed in the subretinal space of micropigs. This enabled the retina to be stimulated subretinally. Since conventional visual evoked potential (VEP) measuring is virtually impossible in the pig from the neurosurgical point of view, epidural recording electrode arrays were positioned over the visual cortex as permanent electrodes. Results The feasibility of temporary implantation of film-bound stimulation electrode arrays was successfully demonstrated in the micropig model. On stimulation with monopolar voltage pulses (1000 to 3000 mV), reproducible epidural VEP measurements (5 to 10 μV) were detected. Conclusions The feasibility of subretinal stimulation of the retina was demonstrated in a retinal model that is similar to the human retina. This animal model therefore offers a suitable means of studying the tolerability of stimulation situations in the course of visual prosthesis development.

APA, Harvard, Vancouver, ISO, and other styles

49

Vartis, A., C. B. Collier, and S. P. Gatt. "Potential Intrathecal Leakage of Solutions Injected into the Epidural Space following Combined Spinal Epidural Anaesthesia." Anaesthesia and Intensive Care 26, no. 3 (1998): 256–61. http://dx.doi.org/10.1177/0310057x9802600304.

Full text

Abstract:

A combined spinal epidural anaesthetic (CSE), by design, produces a deliberate multicompartment block across a breached dural membrane. Since the lateral holes of the epidural catheter may lie in close proximity to the dural puncture site, a bolus solution of drug injected via the epidural catheter has the potential to leak through the dural puncture into the subarachnoid space. The aim of this study was to determine the incidence of intrathecal leak by performing an epidurogram. Fifteen patients undergoing surgery with a CSE anaesthetic using a 16 gauge Tuohy/26 gauge pencil point needle were studied. Within three hours of catheter insertion, 12 ml of contrast (iohexol 300 mg/ml) was injected via the epidural catheter under fluoroscopic control with screen recording and exposure of lateral and anteroposterior X-ray plates. All films were later reviewed for evidence of intrathecal spread. We did not observe any evidence of intrathecal spread of contrast. However, caution should be observed during administration of an intraoperative bolus dose of analgesic agent via a catheter inserted as part of a combined spinal epidural anaesthetic technique, particularly with the use of hydrophilic opiods.

APA, Harvard, Vancouver, ISO, and other styles

50

Alahi, Md Eshrat E., Yonghong Liu, Sara Khademi, et al. "Slippery Epidural ECoG Electrode for High-Performance Neural Recording and Interface." Biosensors 12, no. 11 (2022): 1044. http://dx.doi.org/10.3390/bios12111044.

Full text

Abstract:

Chronic implantation of an epidural Electrocorticography (ECoG) electrode produces thickening of the dura mater and proliferation of the fibrosis around the interface sites, which is a significant concern for chronic neural ECoG recording applications used to monitor various neurodegenerative diseases. This study describes a new approach to developing a slippery liquid-infused porous surface (SLIPS) on the flexible ECoG electrode for a chronic neural interface with the advantage of increased cell adhesion. In the demonstration, the electrode was fabricated on the polyimide (PI) substrate, and platinum (Pt)-gray was used for creating the porous nanocone structure for infusing the silicone oil. The combination of nanocone and the infused slippery oil layer created the SLIPS coating, which has a low impedance (4.68 kΩ) level favourable for neural recording applications. The electrochemical impedance spectroscopy and equivalent circuit modelling also showed the effect of the coating on the recording site. The cytotoxicity study demonstrated that the coating does not have any cytotoxic potentiality; hence, it is biocompatible for human implantation. The in vivo (acute recording) neural recording on the rat model also confirmed that the noise level could be reduced significantly (nearly 50%) and is helpful for chronic ECoG recording for more extended neural signal recording applications.

APA, Harvard, Vancouver, ISO, and other styles

Journal articles on the topic 'Epidural recordings'

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles