Invasive Electrodes Research Articles

Chronic implantable flexible serpentine probe reveals impaired spatial coding of place cells in epilepsy

Abstract Developing minimally invasive and reliable electrode probes for neural signal recording is crucial for advancing neuroscience and treating major brain disorders. Flexible neural probes offer superior long-term recording capabilities over traditional rigid probes. This study introduces a parylene-based serpentine electrode probe for stable, long-term neural monitoring. Inspired by the flexibility and morphology of snakes, the probe's serpentine design ensures stable anchorage within the brain tissue during subject movement. The probe features a hydrophilic surface and is combined with a biodegradable silk fibroin-PEG coating, significantly enhancing biocompatibility and mitigating inflammatory responses. In vivo experiments demonstrate that these probes maintain stable, high-quality neural recordings for over eight months. The probes are also used to investigate the neural bases of epilepsy-induced cognitive deficits. By analyzing place cell dynamics in mice pre- and post-epileptic events, we identified the correlation between impaired spatial encoding and the observed cognitive deficits in epileptic mice. This study highlights the potential of our flexible probes in neurological research and medical applications.

A diagnostic study on the application of segmental somatosensory evoked potential examination to acquired premature ejaculation.

Premature ejaculation (PE), affecting approximate 5%, has an unclear pathogenesis, limited treatment efficacy, and a lack of effective diagnostic methods. This prospective diagnostic study aimed to compare segmental dorsal penile nerve somatosensory evoked potentials (DNSEP) differences among patients with acquired premature ejaculation (APE), primary premature ejaculation (PPE), and healthy controls. This prospective diagnostic study examined patients suffering from PE who visited the outpatient clinic of the Department of Urology of the Second Affiliated Hospital of Zhejiang University School of Medicine from January 1, 2022 to February 28, 2023. According to the definition of PE by the ISSM, 16 cases comprised the healthy control group, 31 in the APE group, and 28 in the PPE group. Each group was examined based on the segmental DNSEP with electrodes recording at multiple locations (the selected location was at the Cz and the C7). The latency time of the evoked potential obtained at Cz was P40, and that obtained at C7 was P30. The P30/P40 ratios of P40, P30, and DNSEP wave amplitudes at C7 and Cz were compared among the 3 groups of patients. No group differences were found in P40 latency at Cz. However, PPE showed higher DNSEP amplitude at Cz, while APE showed lower amplitudes compared with controls. Both APE and PPE had significantly shorter P30 latency at C7 than controls. SEP amplitude at C7 was similar in APE and PPE but lower than in controls. The P30/P40 ratio was lower in APE compared with PPE and controls. Segmental SEP may offer more assistance in localizing neurological lesions, potentially guiding clinical treatment. In this study, the innovative use of the P30/P40 ratio was proposed, maintaining consistency in emotional states and measurement conditions for the same patient. However, limitations include a restricted number of patient cases and challenges in obtaining a diverse control group, potentially introducing bias. In addition, not considering subclinical premature ejaculation and the comorbidity of PE + ED (LCEE) in patient stratification is another limitation of this study. Results suggest a correlation between secondary PE and underlying conditions, such as obesity and lumbar spine injuries. The study validates multi-site somatosensory-evoked potential examination for locating neural lesions but acknowledges the need for future invasive needle electrode AEP testing to analyze neuropathological changes more comprehensively. In conclusion, segmental DNSEP examination aids in localizing neuropathy in APE patients, and the P30/P40 ratio proves more accurate in diagnosing APE than P40 alone.

MXene-coated piezoelectric poly-L-lactic acid membrane accelerates wound healing by biomimicking low-voltage electrical pulses

Electrical stimulation therapy is effective in promoting wound healing by rescuing the decreased endogenous electrical field, where self-powered and miniaturized devices such as nanogenerators become the emerging trends. While high-voltage and unidirectional electric field may pose thermal effect and damage to the skin, nanogenerators with lower voltages, pulsed or bidirectional currents, and less invasive electrodes are preferred. Herein, we construct a polydopamine (PDA)-modified poly-L-lactic acid (PLLA) /MXene (PDMP/MXene) nanofibrous composite membrane that generates piezoelectric voltages matching the transepithelial potential (TEP) to accelerate wound healing. PDA coating not only enhances the piezoelectricity of PLLA by dipole attraction and alignment, but also increases its hydrophilicity and facilitates subsequent MXene adhesion for electrical conductivity and stability in physiological environment. When applied as wound dressings in mice, the PDMP/MXene membranes act as a nanogenerators with reduced internal resistances and satisfactory piezoelectric performances that resemble bioelectric potentials (~10 mV) responding to physical activities. The membrane significantly accelerates wound closure by facilitating fibroblast migration, collagen deposition and angiogenesis, and suppressing the expression of inflammatory responses. This piezoelectric fibrous membrane therefore provides a convenient solution for speeding up wound healing by sustained low voltage mimicking bioelectricity, better cell affinity.

Feasibility, Safety, and Performance of Full-Head Subscalp EEG Using Minimally Invasive Electrode Implantation

Feasibility, Safety, and Performance of Full-Head Subscalp EEG Using Minimally Invasive Electrode Implantation

Evaluating Bacterial Nanocellulose Interfaces for Recording Surface Biopotentials from Plants.

The study of plant electrophysiology offers promising techniques to track plant health and stress in vivo for both agricultural and environmental monitoring applications. Use of superficial electrodes on the plant body to record surface potentials may provide new phenotyping insights. Bacterial nanocellulose (BNC) is a flexible, optically translucent, and water-vapor-permeable material with low manufacturing costs, making it an ideal substrate for non-invasive and non-destructive plant electrodes. This work presents BNC electrodes with screen-printed carbon (graphite) ink-based conductive traces and pads. It investigates the potential of these electrodes for plant surface electrophysiology measurements in comparison to commercially available standard wet gel and needle electrodes. The electrochemically active surface area and impedance of the BNC electrodes varied based on the annealing temperature and time over the ranges of 50 °C to 90 °C and 5 to 60 min, respectively. The water vapor transfer rate and optical transmittance of the BNC substrate were measured to estimate the level of occlusion caused by these surface electrodes on the plant tissue. The total reduction in chlorophyll content under the electrodes was measured after the electrodes were placed on maize leaves for up to 300 h, showing that the BNC caused only a 16% reduction. Maize leaf transpiration was reduced by only 20% under the BNC electrodes after 72 h compared to a 60% reduction under wet gel electrodes in 48 h. On three different model plants, BNC-carbon ink surface electrodes and standard invasive needle electrodes were shown to have a comparable signal quality, with a correlation coefficient of >0.9, when measuring surface biopotentials induced by acute environmental stressors. These are strong indications of the superior performance of the BNC substrate with screen-printed graphite ink as an electrode material for plant surface biopotential recordings.

Haemodynamics of stent-mounted neural interfaces in tapered and deformed blood vessels

The endovascular neural interface provides an appealing minimally invasive alternative to invasive brain electrodes for recording and stimulation. However, stents placed in blood vessels have long been known to affect blood flow (haemodynamics) and lead to neointimal growth within the blood vessel. Both the stent elements (struts and electrodes) and blood vessel wall geometries can affect the mechanical environment on the blood vessel wall, which could lead to unfavourable vascular remodelling after stent placement. With increasing applications of stents and stent-like neural interfaces in venous blood vessels in the brain, it is necessary to understand how stents affect blood flow and tissue growth in veins. We explored the haemodynamics of a stent-mounted neural interface in a blood vessel model. Results indicated that blood vessel deformation and tapering caused a substantial change to the lumen geometry and the haemodynamics. The neointimal proliferation was evaluated in sheep implanted with an endovascular neural interface. Analysis showed a negative correlation with the mean Wall Shear Stress pattern. The results presented here indicate that the optimal stent oversizing ratio must be considered to minimise the haemodynamic impact of stenting.

Multiscale Modeling of Magnetoelectric Nanoparticles for the Analysis of Spatially Selective Neural Stimulation.

The growing field of nanoscale neural stimulators offers a potential alternative to larger scale electrodes for brain stimulation. Nanoelectrodes made of magnetoelectric nanoparticles (MENPs) can provide an alternative to invasive electrodes for brain stimulation via magnetic-to-electric signal transduction. However, the magnetoelectric effect is a complex phenomenon and challenging to probe experimentally. Consequently, quantifying the stimulation voltage provided by MENPs is difficult, hindering precise regulation and control of neural stimulation and limiting their practical implementation as wireless nanoelectrodes. The work herein develops an approach to determine the stimulation voltage for MENPs in a finite element analysis (FEA) model. This model is informed by atomistic material properties from ab initio Density Functional Theory (DFT) calculations and supplemented by experimentally obtainable nanoscale parameters. This process overcomes the need for experimentally inaccessible characteristics for magnetoelectricity, and offers insights into the effect of the more manageable variables, such as the driving magnetic field. The model's voltage is compared to in vivo experimental data to assess its validity. With this, a predictable and controllable stimulation is simulated by MENPs, computationally substantiating their spatial selectivity. This work proposes a generalizable and accessible method for evaluating the stimulation capability of magnetoelectric nanostructures, facilitating their realization as wireless neural stimulators in the future.

Magnetically Compatible Brain Electrode Arrays Based on Single-Walled Carbon Nanotubes for Long-Term Implantation

Advancements in brain–machine interfaces and neurological treatments urgently require the development of improved brain electrodes applied for long-term implantation, where traditional and polymer options face challenges like size, tissue damage, and signal quality. Carbon nanotubes are emerging as a promising alternative, combining excellent electronic properties and biocompatibility, which ensure better neuron coupling and stable signal acquisition. In this study, a new flexible brain electrode array based on 99.99% purity of single-walled carbon nanotubes (SWCNTs) was developed, which has 30 um × 40 um size, about 5.1 kΩ impedance, and 14.01 dB signal-to-noise ratio (SNR). The long-term implantation experiment in vivo in mice shows the proposed brain electrode can maintain stable LFP signal acquisition over 12 weeks while still achieving an SNR of 3.52 dB. The histological analysis results show that SWCNT-based brain electrodes induced minimal tissue damage and showed significantly reduced glial cell responses compared to platinum wire electrodes. Long-term stability comes from SWCNT’s biocompatibility and chemical inertness, the electrode’s flexible and fine structure. Furthermore, the new brain electrode array can function effectively during 7-Tesla magnetic resonance imaging, enabling the collection of local field potential and even epileptic discharges during the magnetic scan. This study provides a comprehensive study of carbon nanotubes as invasive brain electrodes, providing a new path to address the challenge of long-term brain electrode implantation.

Normal variants with an epileptiform appearance in electroencephalograms. A literature review and clinical implications

Normal epileptiform-like variants or benign epileptiform variants are a diagnostic challenge in the interpretation of electroencephalograms, which require the knowledge and extensive experience of those responsible for the electroencephalographic report. They include a heterogeneous group of findings, some quite uncommon, initially related to epilepsy and various neurological conditions. Most of them are currently considered variants with no pathological significance, and their over-interpretation usually leads to misdiagnosis and the establishment of unnecessary treatments. Prevalence data are variable and usually come from selected populations, so they are difficult to extrapolate to a healthy population. Studies with invasive electrodes and recent series link some of these variants with epilepsy. We aim to review the characteristics and prevalence of the main benign epileptiform variants and to update their clinical significance.

Recent Advances in Polymer-based Thin-film Electrode for ECoG Applications

Electrocorticography (ECoG) has garnered widespread attention due to its superior signal resolution compared to conventional electroencephalogram (EEG). While ECoG signal acquisition entails invasiveness, the invasive rigid electrode inevitably inflicts damage...

Reduced graphene oxide-functionalized polymer microneedle for continuous and wide-range monitoring of lactate in interstitial fluid

Despite substantial developments in minimally invasive lactate monitoring microneedle electrodes, most such electrode developments have focused on either sensitivity or invasiveness while ignoring a wide range of detection, which is the most important factor in measuring the normal range of lactate in interstitial fluid (ISF). Herein, we present a polymer-based planar microneedle electrode fabrication using microelectromechanical and femtosecond laser technology for the continuous monitoring of lactate in ISF. The microneedle is functionalized with two-dimensional reduced graphene oxide (rGO) and electrochemically synthesized platinum nanoparticles (PtNPs). A particular quantity of Nafion (1.25 wt%) is applied on top of the lactate enzyme to create a diffusion-controlled membrane. Due to the combined effects of the planar structure of the microneedle, rGO, and membrane, the biosensor exhibited excellent linearity up to 10 mM lactate with a limit of detection of 2.04 μM, high sensitivity of 43.96 μA mM−1cm−2, a reaction time of 8 s and outstanding stability, selectivity, and repeatability. The feasibility of the microneedle is evaluated by using it to measure lactate concentrations in artificial ISF and human serum. The results demonstrate that the microneedle described here has great potential for use in real-time lactate monitoring for use in sports medicine and treatment.

The ultra-thin, minimally invasive surface electrode array NeuroWeb for probing neural activity

Electrophysiological recording technologies can provide valuable insights into the functioning of the central and peripheral nervous systems. Surface electrode arrays made of soft materials or implantable multi-electrode arrays with high electrode density have been widely utilized as neural probes. However, neither of these probe types can simultaneously achieve minimal invasiveness and robust neural signal detection. Here, we present an ultra-thin, minimally invasive neural probe (the “NeuroWeb”) consisting of hexagonal boron nitride and graphene, which leverages the strengths of both surface electrode array and implantable multi-electrode array. The NeuroWeb open lattice structure with a total thickness of 100 nm demonstrates high flexibility and strong adhesion, establishing a conformal and tight interface with the uneven mouse brain surface. In vivo electrophysiological recordings show that NeuroWeb detects stable single-unit activity of neurons with high signal-to-noise ratios. Furthermore, we investigate neural interactions between the somatosensory cortex and the cerebellum using transparent dual NeuroWebs and optical stimulation, and measure the times of neural signal transmission between the brain regions depending on the pathway. Therefore, NeuroWeb can be expected to pave the way for understanding complex brain networks with optical and electrophysiological mapping of the brain.

Vestibular function after simultaneous bilateral cochlear implantation in adults.

Binaural hearing enhances speech intelligibility, source localization, and speech comprehension in noisy environments. Although bilateral cochlear implantation (CI) offers several benefits, concerns arise regarding the risk of bilateral postoperative vestibular dysfunction with simultaneous CI. This study aimed to longitudinally evaluate changes in vestibular function in adult patients who underwent simultaneous bilateral CI using minimally invasive electrodes and surgical techniques. A retrospective review was conducted on 10 patients who underwent simultaneous bilateral CI at our hospital. Vertigo symptoms and vestibular function test results were examined preoperatively, 1-6 months postoperatively, and 1 year postoperatively. Nystagmus tests, caloric reflex tests, vestibular evoked myogenic potentials (VEMP) measurements, and static stabilometry were performed as vestibular function tests. Although an initial transient decline in vestibular function was observed, no significant long-term decline was observed in the caloric reflex test, ocular VEMP (oVEMP), or cervical VEMP (cVEMP). Moreover, regardless of the presence or absence of abnormalities in caloric reflex, oVEMP, or cVEMP, no significant deterioration was detected in the static stabilometer test. While two patients reported preoperative dizziness, all patients were symptom-free 1 year postoperatively. The findings suggest that using current minimally invasive electrodes and surgical techniques in simultaneous bilateral CI leads to temporary vestibular function decline postoperatively. However, most patients experience a recovery in function over time, highlighting the potential safety and efficacy of the procedure. Simultaneous bilateral CI surgery is viable, depending on the patient's auditory needs and burden.

A Hyperflexible Electrode Array for Long-Term Recording and Decoding of Intraspinal Neuronal Activity.

Neural interfaces for stable access to the spinal cord (SC) electrical activity can benefit patients with motor dysfunctions. Invasive high-density electrodes can directly extract signals from SC neuronal populations that can be used for the facilitation, adjustment, and reconstruction of motor actions. However, developing neural interfaces that can achieve high channel counts and long-term intraspinal recording remains technically challenging. Here, a biocompatible SC hyperflexible electrode array (SHEA) with an ultrathin structure that minimizes mechanical mismatch between the interface and SC tissue and enables stable single-unit recording for more than 2 months in mice is demonstrated. These results show that SHEA maintains stable impedance, signal-to-noise ratio, single-unit yield, and spike amplitude after implantation into mouse SC. Gait analysis and histology show that SHEA implantation induces negligible behavioral effects and Inflammation. Additionally, multi-unit signals recorded from the SC ventral horn can predict the mouse's movement trajectory with a high decoding coefficient of up to 0.95. Moreover, during step cycles, it is found that the neural trajectory of spikes and low-frequency local field potential (LFP) signal exhibits periodic geometry patterns. Thus, SHEA can offer an efficient and reliable SC neural interface for monitoring and potentially modulating SC neuronal activity associated with motor dysfunctions.

In Situ Forming of Nitric Oxide and Electric Stimulus for Nerve Therapy by Wireless Chargeable Gold Yarn-Dynamos.

Endogenous signals, namely nitric oxide (NO) and electrons, play a crucial role in regulating cell fate as well as the vascular and neuronal systems. Unfortunately, utilizing NO and electrical stimulation in clinical settings can be challenging due to NO's short half-life and the invasive electrodes required for electrical stimulation. Additionally, there is a lack of tools to spatiotemporally control gas release and electrical stimulation. To address these issues, an "electromagnetic messenger" approach that employs on-demand high-frequency magnetic field (HFMF) to trigger NO release and electrical stimulation for restoring brain function in cases of traumatic brain injury is introduced. The system comprises a NO donor (poly(S-nitrosoglutathione), pGSNO)-conjugated on a gold yarn-dynamos (GY) and embedded in an implantable silk in a microneedle. When subjected to HFMF, conductive GY induces eddy currents that stimulate the release of NO from pGSNO. This process significantly enhances neural stem cell (NSC) synapses' differentiation and growth. The combined strategy of using NO and electrical stimulation to inhibit inflammation, angiogenesis, and neuronal interrogation in traumatic brain injury is demonstrated in vivo.

Minimally invasive extraocular cranial nerve electromyography.

A reluctance to monitor extraocular cranial nerve (EOCN) function has restricted skull base surgery worldwide. Spontaneous and triggered electromyography (EMG) monitoring can be recorded intraoperatively to identify and assess potential cranial nerve injury. Determining the conductive function of EOCNs requires the collection of clear, reliable, and repeatable compound muscle action potentials (CMAPs) secondary to stimulation. EOCN EMG needle electrodes can, although infrequently, cause ocular morbidity including hematoma, edema, and scleral laceration. The aim of this study was to ascertain if minimally invasive 7-mm superficial needle electrodes would record CMAPs as well as standard 13-mm intraorbital electrodes. Conventionally, the authors have monitored EOCN function with intraorbital placement of paired 13-mm needle electrodes into three extraocular muscles: medial rectus, superior oblique, and lateral rectus. A prospective case-control study was performed using shorter (7-mm) needle electrodes. A single minimally invasive electrode was placed superficially near each extraocular muscle and coupled with a common reference. CMAPs were recorded from the minimally invasive electrodes and compared with CMAPs recorded from the paired intraorbital electrodes. The presence or absence of CMAPs was analyzed and compared among EMG recording techniques. A total of 429 CMAPs were analyzed from 71 EOCNs in 25 patients. The experimental setup yielded 167 true-positive (39%), 106 false-positive (25%), 17 false-negative (4%), and 139 true-negative (32%) responses. These values were used to calculate the sensitivity (91%), specificity (57%), positive predictive value (61%), and negative predictive value (89%). EOCN electrodes were placed in 82 total eyes in 58 patients (CMAPs were obtained in 25 patients). Twenty-six eyes showed some degree of edema, bruising, or bleeding, which was transient and self-resolving. Three eyes in different patients had complications from needle placement or extraction including conjunctival hemorrhage, periorbital ecchymosis, and corneal abrasion, ptosis, and upper eyelid edema. Because of artifact contamination, 106 false-positive responses (25%), and 17 false-negative responses (4%), the minimally invasive EMG technique cannot reliably record CMAP responses intraoperatively as well as the intraorbital technique. Less-invasive techniques can lead to an inaccurate EOCN assessment and potential postoperative morbidity. EOCN palsies can be debilitating and lifelong; therefore, the benefits of preserving EOCN function outweigh the potential risks of morbidity from electrode placement. EMG monitoring with intraorbital electrodes remains the most reliable method of intraoperative EOCN assessment.

Advancement of the Electrochemical Performance of Stainless-Steel EEG Electrodes by Functionalizing with Carbon Nanotubes and Antibiofouling Molecules

Understanding brain function and neurological disorders are essential to develop therapeutic strategies such as neuropharmacological medications and implantable biomedical tools to treat brain-related disorders. Implantable neural electrodes can deliver in-depth knowledge of brain activity and disorders by recording real-time brain signals. Epilepsy is an electrophysiological brain disorder caused by genetic factors or a brain injury. Electroencephalography (EEG) is a standard technique that provides more specific information about epilepsy. Both invasive and non-invasive EEG electrodes are used to study epilepsy and possess high temporal resolution. Invasive EEG electrodes are useful for localizing the brain's regions where epilepsy arises. EEG electrodes are mainly metal-based electrodes. Stainless steel, platinum, gold, tin, and silver are commonly used metals. Electrode material plays a critical role in the accuracy of the brain signal measurements and consistent performance in chronic applications. Stainless steel EEG electrodes are successfully used in EEG signal monitoring in vivo; however, stainless steel can undergo chloride-induced corrosion and biofouling over time. Corrosion and biofouling can negatively affect the impedance of the EEG electrodes resulting in poor signal recording and inconsistent performance. The current study reports the advancement of the performance of stainless-steel EEG electrodes by functionalizing with vertically aligned carbon nanotubes (CNTs) and zwitterionic phenyl phosphorylcholine (PPC) molecules. CNTs are conductive and biocompatible nanomaterial which have been successfully used for neural interfacing applications. The results show that the electrochemical performance of the EEG electrodes was significantly improved after functionalization with vertically aligned CNTs. Electrochemically grafting of zwitterionic PPC molecules onto CNTs further improved electrochemical performance and introduced anti-biofouling properties.

Development of soft dry electrodes: from materials to structure design

Bioelectric signals reflect our daily physiological activities, which can be recorded in the form of electroencephalography, electrocardiography, electromyography, etc. The traditional Ag/AgCl wet electrode is the gold standard for clinical monitoring of bioelectrical signals at present, while complicated preparation and gel evaporation limit its long-term application. Therefore, it is meaningful to research dry electrodes without conductive paste or additional adhesives. Unfortunately, the high interface impedance between electrodes and skin is a fatal defect of dry electrodes, which leads to excessive noise levels and poor signal quality. Consequently, more efforts are required to achieve conformal contact between dry electrodes and skin to reduce the contact impedance. From this perspective, we review the recent progress in capacitive electrodes, invasive microneedle electrodes, and common-contact dry electrodes. Material selection and structural design to obtain conformal contact are highlighted. Finally, we propose the future development direction of dry electrodes.

Unsupervised neural decoding of signals recorded by thin-film electrode arrays implanted in muscles using autoencoding with a physiologically derived optimisation criterion

We present an autoencoder that learns the discharge times of individual motor units (MU) by processing multichannel electromyogram (EMG) recordings obtained by electrode arrays implanted in muscles, thereby providing a neural interface with the spinal cord. To this end, after preprocessing of the EMG via convolutive sphering, the encoder is constrained to apply an orthogonal transformation to the spatial data and the optimisation criterion enforces a temporal sparsity constraint. These constraints are based on the theoretical modelling of EMG generation. This decomposition method was evaluated on both simulated and experimental signals. For simulated signals, with a ratio of 1.5 between observations and sources, the average detection accuracy was 94% for up to 60 sources for SNR 20 dB. Moreover, the detection accuracy did not significantly decrease when decreasing the SNR to values as low as 0 dB. Experimental signals were collected in humans with thin-film invasive electrodes implanted in the tibialis anterior muscle. The results showed an accuracy on experimental data >90%. Moreover, the proposed method outperformed a state-of-the-art blind source separation approach in terms of the number of reliably detected motor units. In conclusion, we have proposed the first fully unsupervised neural network approach to the problem of neural decoding of intramuscular EMG time series by translating the available theoretical knowledge on the signal properties into an autoencoding architecture tailored to the decomposition problem.

Accuracy of Depth Electrodes is Not Time-Dependent in Robot-Assisted Stereoelectroencephalography in a Pediatric Population.

Robot-assisted stereoelectroencephalography (sEEG) is steadily supplanting traditional frameless and frame-based modalities for minimally invasive depth electrode placement in epilepsy workup. Accuracy rates similar to gold-standard frame-based techniques have been achieved, with improved operative efficiency. Limitations in cranial fixation and placement of trajectories in pediatric patients are believed to contribute to a time-dependent accumulation of stereotactic error. Thus, we aim to study the impact of time as a marker of cumulative stereotactic error during robotic sEEG. All patients between October 2018 and June 2022 who underwent robotic sEEG were included. Radial errors at entry and target points as well as depth and Euclidean distance errors were collected for each electrode, excluding those with errors over 10 mm. Target point errors were standardized by planned trajectory length. ANOVA and error rates over time were analyzed using GraphPad Prism 9. Forty-four patients met inclusion criteria for a total of 539 trajectories. Number of electrodes placed ranged from 6 to 22. Average root mean squared error was 0.45 ± 0.12 mm. Average entry, target, depth, and Euclidean distance errors were 1.12 ± 0.41 mm, 1.46 ± 0.44 mm, -1.06 ± 1.43 mm, and 3.01 ± 0.71 mm, respectively. There was no significant increased error with each sequential electrode placed (entry error P -value = .54, target error P -value = .13, depth error P -value = .22, Euclidean distance P -value = .27). No decremental accuracy over time was observed. This may be secondary to our workflow which prioritizes oblique and longer trajectories first and then into less error-prone trajectories. Further study on the effect of level of training may reveal a novel difference in error rates.