Electrophysiological Monitoring Research Articles

Versatile micro-electrode array to monitor human iPSC derived 3D neural tissues at air-liquid interface

Engineered 3D neural tissues made of neurons and glial cells derived from human induced pluripotent stem cells (hiPSC) are among the most promising tools in drug discovery and neurotoxicology. They represent a cheaper, faster, and more ethical alternative to in vivo animal testing that will likely close the gap between in vitro animal models and human clinical trials. Micro-Electrode Array (MEA) technology is known to provide an assessment of compound effects on neural 2D cell cultures and acute tissue preparations by real-time, non-invasive, and long-lasting electrophysiological monitoring of spontaneous and evoked neuronal activity. Nevertheless, the use of engineered 3D neural tissues in combination with MEA biochips still involves series of constraints, such as drastically limited diffusion of oxygen and nutrients within tissues mainly due to the lack of vascularization. Therefore, 3D neural tissues are extremely sensitive to experimental conditions and require an adequately designed interface that provides optimal tissue survival conditions. A well-suited technique to overcome this issue is the combination of the Air-Liquid Interface (ALI) tissue culture method with the MEA technology. We have developed a full 3D neural tissue culture process and a data acquisition system composed of high-end electronics and novel MEA biochips based on porous, flexible, thin-film membranes integrating recording electrodes, named as “Strip-MEA,” to allow the maintenance of an ALI around the 3D neural tissues. The main motivation of the porous MEA biochips development was the possibility to monitor and to study the electrical activity of 3D neural tissues under different recording configurations, (i) the Strip-MEA can be placed below a tissue, (ii) or by taking advantage of the ALI, be directly placed on top of the tissue, or finally, (iii) it can be embedded into a larger neural tissue generated by the fusion of two (or more) tissues placed on both sides of the Strip-MEA allowing the recording from its inner part. This paper presents the recording and analyses of spontaneous activity from the three positioning configurations of the Strip-MEAs. Obtained results are discussed with the perspective of developing in vitro models of brain diseases and/or impairment of neural network functioning.

Next-Generation Cardiac Interfacing Technologies Using Nanomaterial-Based Soft Bioelectronics.

Cardiac interfacing devices are essential components for the management of cardiovascular diseases, particularly in terms of electrophysiological monitoring and implementation of therapies. However, conventional cardiac devices are typically composed of rigid and bulky materials and thus pose significant challenges for effective long-term interfacing with the curvilinear surface of a dynamically beating heart. In this regard, the recent development of intrinsically soft bioelectronic devices using nanocomposites, which are fabricated by blending conductive nanofillers in polymeric and elastomeric matrices, has shown great promise. The intrinsically soft bioelectronics not only endure the dynamic beating motion of the heart and maintain stable performance but also enable conformal, reliable, and large-area interfacing with the target cardiac tissue, allowing for high-quality electrophysiological mapping, feedback electrical stimulations, and even mechanical assistance. Here, we explore next-generation cardiac interfacing strategies based on soft bioelectronic devices that utilize elastic conductive nanocomposites. We first discuss the conventional cardiac devices used to manage cardiovascular diseases and explain their undesired limitations. Then, we introduce intrinsically soft polymeric materials and mechanical restraint devices utilizing soft polymeric materials. After the discussion of the fabrication and functionalization of conductive nanomaterials, the introduction of intrinsically soft bioelectronics using nanocomposites and their application to cardiac monitoring and feedback therapy follow. Finally, comments on the future prospects of soft bioelectronics for cardiac interfacing technologies are discussed.

Application value of intraoperative electrophysiological monitoring in cerebral eloquent area glioma surgery: a retrospective cohort study

IntroductionSurgery for gliomas involving eloquent areas is a very challenging microsurgical procedure. Maximizing both the extent of resection (EOR) and preservation of neurological function have always been the focus of attention. Intraoperative neurophysiological monitoring (IONM) is widely used in this kind of surgery. The purpose of this study was to evaluate the efficacy of IONM in eloquent area glioma surgery.MethodsSixty-eight glioma patients who underwent surgical treatment from 2014 to 2019 were included in this retrospective cohort study, which focused on eloquent areas. Clinical indicators and IONM data were analysed preoperatively, two weeks after surgery, and at the final follow-up. Logistic regression, Cox regression, and Kaplan‒Meier analyses were performed, and nomograms were then established for predicting prognosis. The diagnostic value of the IONM indicator was evaluated by the receiver operating characteristic (ROC) curve.ResultsIONM had no effect on the postoperative outcomes, including EOR, intraoperative bleeding volume, duration of surgery, length of hospital stay, and neurological function status. However, at the three-month follow-up, the percentage of patients who had deteriorated function in the monitored group was significantly lower than that in the unmonitored group (23.3% vs. 52.6%; P < 0.05). Logistic regression analysis showed that IONM was a significant factor in long-term neurological function (OR = 0.23, 95% CI (0.07–0.70). In the survival analysis, long-term neurological deterioration indicated worsened overall survival (OS) and progression-free survival (PFS). A prognostic nomogram was established through Cox regression model analysis, which could predict the probability 3-year survival rate. The concordance index was 0.761 (95% CI 0.734–0.788). The sensitivity and specificity of IONM evoked potential (SSEP and TCeMEP) were 0.875 and 0.909, respectively. In the ROC curve analysis, the area under the curve (AUC) for the SSEP and TCeMEP curves was 0.892 (P < 0.05).ConclusionsThe application of IONM could improve long-term neurological function, which is closely related to prognosis and can be used as an independent prognostic factor. IONM is practical and widely available for predicting postoperative functional deficits in patients with eloquent area glioma.

Direct Laser Processing and Functionalizing PI/PDMS Composites for an On-Demand, Programmable, Recyclable Device Platform.

Skin-interfaced high-sensitive biosensing systems to detect electrophysiological and biochemical signals have shown great potential in personal health monitoring and disease management. However, the integration of 3D porous nanostructures for improved sensitivity and various functional composites for signal transduction/processing/transmission often relies on different materials and complex fabrication processes, leading to weak interfaces prone to failure upon fatigue or mechanical deformations. The integrated system also needs additional adhesive to strongly conform to the human skin, which can also cause irritation, alignment issues, and motion artifacts. This work introduces a skin-attachable, reprogrammable, multifunctional, adhesive device patch fabricated by simple and low-cost laser scribing of an adhesive composite with polyimide powders and amine-based ethoxylated polyethylenimine dispersed in the silicone elastomer. The obtained laser-induced graphene (LIG) in the adhesive composite can be further selectively functionalized with conductive nanomaterials or enzymes for enhanced electrical conductivity or selective sensing of various sweat biomarkers. The possible combination of the sensors for real-time biofluid analysis and electrophysiological signal monitoring with RF energy harvesting and communication promises a standalone stretchable adhesive device platform based on the same material system and fabrication process. This article is protected by copyright. All rights reserved.

Assessment of dynamic cognitive performance under different thermal conditions by multiple physiological signals

A method to evaluate cognitive performance under different thermal conditions by multiple physiological signals is proposed. Heart rate (HR), heart rate variability (RMSSD), skin conductance level (SCL), skin conductance response (SCR) magnitude and SCR total frequency were measured by a multichannel electrophysiological signal monitor, which were interpreted as thermal stress indicators that can characterize cognitive performance of subjects during cognitive stimulation tasks. In the experiment, the indoor air temperature is the independent variable, ranging from 18°C to 33°C, with a step length of three degrees. Other indoor environmental quality (IEQ) parameters are controlled variables. In each experiment, subjects subjectively voted on thermal sensation and cognitive load, and performed cognitive stimulation tasks to evaluate cognitive performance. The study found that different physiological indicators have different "thermosensitivity" zones, indicating variations in thermal attributes. Moreover, the influence mechanism of thermal conditions on the effectiveness levels of three different cognitive functions, namely identification, decision and action, were found to be diverse. Additionally, this paper utilized machine learning algorithms to construct fatigue loss function and residual interference function for cognitive performance, effectively correcting cognitive performance errors caused by fatigue and task superimposition. The feasibility of predicting cognitive performance and thermal comfort by multiple physiological indicators is validated in this study.

459 Outcome of Surgeries of Pan Brachial Plexus Injuries - Our 10 Years Experience

INTRODUCTION: Brachial plexus injuries are very much devastating and lead to significant socioeconomic and mental burden to the affected person and his family. In the early days of 20th century many authors were in favour of conservative management even the amputation of affected limb. But in later decades due to development in technological advancement of operating microscope, intraoperative electrophysiological monitoring, biological tissue glue etc. the results of surgical repair are beyond the imagination that could be done previously. METHODS: Our study is a Retrospective observational analytical study in which we included patients of Pan brachial plexus injury operated under the Department of Neurosurgery from April 2011 till February 2023 (excluding covid period from March 2020 to September 2021) at apex trauma center AIIMS Delhi, India. Demographic details, mode of injury, surgery performed and outcome were analyzed. Data was extracted from patient’s casualty, ICU and OT records and analyzed using SPSS version 29.0.0.0. Analysis of outcome was taken in terms of improvement in motor power and quality of life. RESULTS: There were 113 patients diagnosed to have Pan brachial plexus injury by clinical examination and supported with brachial plexus MRI, NCV and EMG of the affected limb. 24 (21.24%) cases underwent Neurolysis only, 17 (15.04%) cases underwent Supraclavicular neurotization only, 24 (21.24%) cases were operated by infraclavicular neurotization and 48 (42.48%) patients were operated by supraclavicular and infraclavicular neurotization both. Respectively 25%, 23.52%, 25% and 35.42% cases had motor and sensory improvement and were able to perform few of their daily activities with lesser support. CONCLUSIONS: In our study at least 25% Patients of Pan brachial plexus injury after surgery got benefited in their routine activity and quality of life thus lesser affected in socioeconomic and psychological front.

Flexible and Stretchable Electrodes for In Vivo Electrophysiological and Electrochemical Monitoring†

Comprehensive SummaryIn vivo monitoring of bioelectrical and biochemical signals with implanted electrodes has received great interest over the past decades. However, this faces huge challenges because of the severe mechanical mismatch between conventional rigid electrodes and soft biological tissues. In recent years, the emergence of flexible and stretchable electrodes offers seamless and conformable biological‐electronic interfaces and has demonstrated significant advantages for in vivo electrochemical and electrophysiological monitoring. This review first summarizes the strategies for electrode fabrication from the point of substrate and conductive materials. Next, recent progress in electrode functionalization for improved performance is presented. Then, the advances of flexible and stretchable electrodes in exploring bioelectrical and biochemical signals are introduced. Finally, we present some challenges and perspectives ranging from electrode fabrication to application.Key ScientistsIn 2001, a seminal work by Kipke et al. first showed flexible polyimide‐based intracortical electrode arrays.[1] This electrode was further expanded to 252‐channel using microelectromechanical systems technology by Stieglitz et al. in 2009 and achieved large‐scale cortical recordings.[2] Later, Lieber et al. created mesh electronics that allow for seamless and minimally invasive three‐dimensional interpenetration with nerve tissues, opening up unique applications for flexible electronics.[3] Subsequently, Rogers et al. described bioresorbable electronics for transient electrical activity recordings in 2016.[4] And Frank et al. proposed polymer electrode arrays capable of resolving single neurons in 2019.[5] It wasn't until 2020 that a significant breakthrough in biochemical signals monitoring by Peng et al. demonstrated functionalized carbon nanotube fibre bundles for multiple disease biomarkers monitoring.[6] Later on, Mooney et al. established the first fully viscoelastic electrode arrays for neural recordings from the brain and heart in 2021.[7] Recently, Bao et al. presented tissue‐mimicking, stretchable neurotransmitter interfaces for monitoring the brain and gut.[8]

Mechanical stimulation and electrophysiological monitoring at subcellular resolution reveals differential mechanosensation of neurons within networks.

A growing consensus that the brain is a mechanosensitive organ is driving the need for tools that mechanically stimulate and simultaneously record the electrophysiological response of neurons within neuronal networks. Here we introduce a synchronized combination of atomic force microscopy, high-density microelectrode array and fluorescence microscopy to monitor neuronal networks and to mechanically characterize and stimulate individual neurons at piconewton force sensitivity and nanometre precision while monitoring their electrophysiological activity at subcellular spatial and millisecond temporal resolution. No correlation is found between mechanical stiffness and electrophysiological activity of neuronal compartments. Furthermore, spontaneously active neurons show exceptional functional resilience to static mechanical compression of their soma. However, application of fast transient (∼500 ms) mechanical stimuli to the neuronal soma can evoke action potentials, which depend on the anchoring of neuronal membrane and actin cytoskeleton. Neurons show higher responsivity, including bursts of action potentials, to slower transient mechanical stimuli (∼60 s). Moreover, transient and repetitive application of the same compression modulates the neuronal firing rate. Seemingly, neuronal networks can differentiate and respond to specific characteristics of mechanical stimulation. Ultimately, the developed multiparametric tool opens the door to explore manifold nanomechanobiological responses of neuronal systems and new ways of mechanical control.

Fully endoscopic microvascular decompression for hemifacial spasm: a clinical study and analysis

Fully endoscopic microvascular decompression (MVD) of the facial nerve is the main surgical treatment for hemifacial spasm. However, the technique presents distinct surgical challenges. We retrospectively analyzed prior cases to consolidate surgical insights and assess clinical outcomes. Clinical data from 16 patients with facial nerve spasms treated at the Department of Neurosurgery in the First Affiliated Hospital of Bengbu Medical College, between August 2020 and July 2023, were retrospectively examined. Preoperatively, all patients underwent magnetic resonance angiography to detect any offending blood vessels; ascertain the relationship between offending vessels, facial nerves, and the brainstem; and detect any cerebellopontine angle lesions. Surgery involved endoscopic MVD of the facial nerve using a mini Sigmoid sinus posterior approach. Various operative nuances were summarized and analyzed, and clinical efficacy, including postoperative complications and the extent of relief from facial paralysis, was evaluated. Fully endoscopic MVD was completed in all patients, with the offending vessels identified and adequately padded during surgery. The offending vessels were anterior inferior cerebellar artery in 12 cases (75%), vertebral artery in 3 cases (18.75%), and posterior inferior cerebellar artery in 1 case (6.25%). Intraoperative electrophysiological monitoring revealed that the lateral spread response of the facial nerve vanished in 15 cases and remained unchanged in 1 case. Postoperative facial spasms were promptly alleviated in 15 cases (93.75%) and delayed in 1 case (6.25%). Two cases of postoperative complications were recorded—one intracranial infection and one case of tinnitus—both were resolved or mitigated with treatment. All patients were subject to follow-up, with no instances of recurrence or mortality. Fully endoscopic MVD of the facial nerve is safe and effective. Proficiency in endoscopy and surgical skills are vital for performing this procedure.

Intracranial electroencephalography reveals effector-independent evidence accumulation dynamics in multiple human brain regions.

Neural representations of perceptual decision formation that are abstracted from specific motor requirements have previously been identified in humans using non-invasive electrophysiology; however, it is currently unclear where these originate in the brain. Here we capitalized on the high spatiotemporal precision of intracranial EEG to localize such abstract decision signals. Participants undergoing invasive electrophysiological monitoring for epilepsy were asked to judge the direction of random-dot stimuli and respond either with a speeded button press (N = 24), or vocally, after a randomized delay (N = 12). We found a widely distributed motor-independent network of regions where high-frequency activity exhibited key characteristics consistent with evidence accumulation, including a gradual buildup that was modulated by the strength of the sensory evidence, and an amplitude that predicted participants' choice accuracy and response time. Our findings offer a new view on the brain networks governing human decision-making.

3D Printed Gallium Battery with Outstanding Energy Storage: Toward Fully Printed Battery‐on‐the‐Board Soft Electronics

AbstractThe last decade observed rapid progress in soft electronics. Yet, the ultimate desired goal for many research fields is to fabricate fully integrated soft‐matter electronics with sensors, interconnects, and batteries, at the ease of pushing a print button. In this work, an important step is taken toward this by demonstrating an ultra‐stretchable thin‐film Silver‐Gallium (Ag‐Ga) battery with an unprecedented combination of areal capacity and mechanical strain tolerance. The Biphasic Gallium‐Carbon anode electrode demonstrates a record‐breaking areal capacity of 78.7 mAh cm−2, and an exceptional stretchability of 170%, showing clear progress over state‐of‐the‐art. The exceptional theoretical capacity of gallium, along with its natural liquid phase self‐healing, and its dendrite‐free operation permits excellent electromechanical cycling. All composites of the battery including liquid‐metal‐based current collectors, and electrodes are sinter‐free and digitally printable at room temperature, enabling the use of a wide range of substrates, including heat‐sensitive polymer films. Consequently, it is demonstrated for the first time multi‐layer, and multi‐material digital printing of complex battery‐on‐the‐board stretchable devices that integrate printed sensor, multiple cells of printed battery, highly conductive interconnects, and silicone chips, and demonstrate a tailor‐made patch for body‐worn electrophysiological monitoring.

Advanced wearable strain sensors: Ionic double network hydrogels with exceptional stretchability, adhesion, anti-freezing properties, and sensitivity

In recent years, achieving satisfactory mechanical and electrical properties in hydrogels at low temperatures has proven challenging. Herein, we developed an superior ionic conductive hydrogel by a simplified one-pot method. The as-prepared Li+/AgNPs@polyacrylamide-co-polyacrylic acid (Li+/AgNPs@PAM/PAAc) double-network hydrogel exhibited remarkable stretchability of up to 1250 % at room temperature and revealed a robust adhesion on different materials, especially up to 44.2 kPa on aluminum. Furthermore, the hydrogel demonstrated high sensitivity with a gage factor (GF) of 3.20 at a strain of 200 %, and performed reliably at low temperature, with a GF of 1.42 at a strain of 100 % at - 40 °C, suggesting the maintenance of excellent mechanical and electrical properties at low temperature. These remarkable advantages highlighted the significantly enhanced performance of the ionic conductive hydrogel for applications in flexible wearable sensing devices, in the areas of intelligent speech, motion recognition, as well as electrophysiological signal monitoring.

Ultrastretchable, Self-Adhesive and conductive MXene nanocomposite hydrogel for body-surface temperature distinguishing and electrophysiological signal monitoring

Epidermal sensors capable of monitoring various physical signals are vital in wearable healthcare applications. MXene-based conductive hydrogels have become promising candidates as skin-attachable sensors for these purposes. However, due to the easy oxidation and weak combination of MXene nanosheets with network matrix, it remains challenging to construct a mechanically tough, highly conductive and skin-conformal hydrogel for reliable signal recording (especially weak electrophysiological signals). Herein, a new conductive MXene-based hydrogel is fabricated through introducing silk fibroin (SF)-modified MXene (MXene-SF) into polyacrylamide (PAM) network. It is demonstrated that the encapsulation of SF on MXene surfaces greatly improves its stability, and meanwhile induces the formation of multiple noncovalent interactions between MXene-SF and PAM chains. The resulting hydrogel exhibits high stretchability (1560 %), remarkable toughness (165 kJ/m3), high conductivity (0.25 S/m) and self-adhesion. This hydrogel is high-sensitive in a large strain range for detecting various human motions. Especially, the high conformal adhesion and low interface impedance make the hydrogel bioelectrodes precisely monitor weak electrophysiological signals (e.g. electromyogram and electrooculogram), successfully achieving sign language translation and eye tracking. Additionally, the hydrogel has great thermosensitive capacities for body temperature monitoring. This study provides a general strategy for designing MXene-based hydrogels with tailored functionalities as flexible electronics.

Long QT Syndrome and WPW Syndrome: A Very Rare Association between Two Causes of Sudden Cardiac Death in a Young Patient

Long QT syndrome (LQT) and WPW syndrome are causes of sudden cardiac death (SCD) in the young, and their association has been rarely reported. A 26-year-old woman presented with recurrent syncope. Her ECG showed a short PR interval, wide QRS (150 ms) due to a delta wave, and QT prolongation (QT 580 ms, QTc 648 ms). ECG monitoring documented recurrent salvos of a self-terminating wide QRS tachycardia, generally slightly polymorphic, sometimes with “torsade des pointes” (TdP) appearance, which were linked to the syncopal/presyncope episodes. Electrophysiologic monitoring diagnosed a right para-hisian accessory pathway with a very short ERP (240 ms baseline, &lt;200 ms after isoproterenol). The pathway was ablated successfully. Despite QRS narrowing (80 ms), QT prolongation persisted after ablation (QT 620 ms, QTc 654 ms), with short runs of TdP, despite beta-blocker treatment, which was increased to the maximal dosage. A dual-chamber implantable cardioverter defibrillator (ICD) was implanted. To our knowledge, this is the first case report of an association between LQT and WPW syndrome in which both conditions are associated with an increased risk of SCD.

Topological MXene Network Enabled Mixed Ion-Electron Conductive Hydrogel Bioelectronics.

Mixed ion-electron conductive (MIEC) bioelectronics has emerged as a state-of-the-art type of bioelectronics for bioelectrical signal monitoring. However, existing MIEC bioelectronics is limited by delamination and transmission defects in bioelectrical signals. Herein, a topological MXene network enhanced MIEC hydrogel bioelectronics that simultaneously exhibits both electrical and mechanical property enhancement while maintaining adhesion and biocompatibility, providing an ideal MIEC bioelectronics for electrophysiological signal monitoring, is introduced. Compared with nontopology hydrogel bioelectronics, the MXene topology increases the dynamic stability of bioelectronics by a factor of 8.4 and the electrical signal by a factor of 10.1 and reduces the energy dissipation by a factor of 20.2. Besides, the topology-enhanced hydrogel bioelectronics exhibits low impedance (<25 Ω) at physiologically relevant frequencies and negligible impedance fluctuation after 5000 stretch cycles. The creation of multichannel bioelectronics with high-fidelity muscle action mapping and gait recognition was made possible by achieving such performance.

Skin preparation-free, stretchable microneedle adhesive patches for reliable electrophysiological sensing and exoskeleton robot control.

High-fidelity and comfortable recording of electrophysiological (EP) signals with on-the-fly setup is essential for health care and human-machine interfaces (HMIs). Microneedle electrodes allow direct access to the epidermis and eliminate time-consuming skin preparation. However, existing microneedle electrodes lack elasticity and reliability required for robust skin interfacing, thereby making long-term, high-quality EP sensing challenging during body movement. Here, we introduce a stretchable microneedle adhesive patch (SNAP) providing excellent skin penetrability and a robust electromechanical skin interface for prolonged and reliable EP monitoring under varying skin conditions. Results demonstrate that the SNAP can substantially reduce skin contact impedance under skin contamination and enhance wearing comfort during motion, outperforming gel and flexible microneedle electrodes. Our wireless SNAP demonstration for exoskeleton robot control shows its potential for highly reliable HMIs, even under time-dynamic skin conditions. We envision that the SNAP will open new opportunities for wearable EP sensing and its real-world applications in HMIs.

Experience in treating children with ocular dyskinesia and hemifacial spasm secondary to pontine tumours adjacent to the fourth ventricle and systematic review.

To investigate the treatment plan and prognosis of children with ocular dyskinesia and hemifacial spasm secondary to pontine tumours adjacent to the fourth ventricle. In this retrospective study, the clinical information of 10 consecutively collected children with ocular dyskinesia and hemifacial spasm secondary to pontine tumours adjacent to the fourth ventricle was analyzed. All 10 children underwent pontine tumour resection through a trans-cerebellomedullary fissure approach; 4 children underwent preoperative diffusion tensor imaging scans to determine the relationship between the tumour and facial nerve nucleus, and the other 6 children underwent intraoperative deep electroencephalography (EEG) tumour monitoring, in which the tumour electrical discharge activity of the tumour was recorded. A voxel distribution map was established to describe the distribution of the tumour location, and patient prognosis was evaluated through clinical and imaging follow-up. All 10 children achieved total tumour resection; 9 tumours were pathologically suggested to be ganglioglioma (WHO grade I), and 1 was a hamartoma. The symptoms of the original ocular dyskinesia and hemifacial spasm disappeared immediately after the operation. The children were followed up for 4-75months, and none of the symptoms recurred; four cases with preoperative diffusion tensor imaging showed that the tumour was close to the facial nerve. Four in six intraoperative electrophysiological monitoring showed that the tumour had electrical discharge behaviour, and the tumour distribution map indicates a high density of tumour presence in the facial nerve nucleus and the nucleus of the abducens nerve. In paediatric patients, the facial symptoms are related to the location and abnormal electrical discharge of the tumour. There is no significant correlation between ocular dyskinesia and the location of the tumour. Conventional antiepileptic therapy for this disease is ineffective, and early surgical intervention for total tumour resection can achieve a clinical curative effect.

A 10-micrometer-thick nanomesh-reinforced gas-permeable hydrogel skin sensor for long-term electrophysiological monitoring.

Hydrogel-enabled skin bioelectronics that can continuously monitor health for extended periods is crucial for early disease detection and treatment. However, it is challenging to engineer ultrathin gas-permeable hydrogel sensors that can self-adhere to the human skin for long-term daily use (>1 week). Here, we present a ~10-micrometer-thick polyurethane nanomesh-reinforced gas-permeable hydrogel sensor that can self-adhere to the human skin for continuous and high-quality electrophysiological monitoring for 8 days under daily life conditions. This research involves two key steps: (i) material design by gelatin-based thermal-dependent phase change hydrogels and (ii) robust thinness geometry achieved through nanomesh reinforcement. The resulting ultrathin hydrogels exhibit a thickness of ~10 micrometers with superior mechanical robustness, high skin adhesion, gas permeability, and anti-drying performance. To highlight the potential applications in early disease detection and treatment that leverage the collective features, we demonstrate the use of ultrathin gas-permeable hydrogels for long-term, continuous high-precision electrophysiological monitoring under daily life conditions up to 8 days.

Emerging epidermal electrodes towards digital health and on-skin digitalization

Epidermal electrodes can be directly attached to the human skin for high-fidelity electrophysiological monitoring owing to their preponderance in thinness, lightweight, conformability, biocompatibility, self-adhesiveness, mechanical flexibility, gas-permeability, etc . These devices have attracted immense attention due to their emerging applications in personalized health care, human/brain-machine interfaces, and soft robotics. This Perspective focuses on the most recent significant progress in this area, especially materials, properties, and applications. Challenges and prospects are summarized to underscore the unexploited areas and future directions toward digital health and on-skin digitalization.

Intracranial recordings reveal high-frequency activity in the human temporal-parietal cortex supporting non-literal language processing.

Non-literal expressions such as sarcasm, metaphor and simile refer to words and sentences that convey meanings or intentions that are different and more abstract than literal expressions. Neuroimaging studies have shown activations in a variety of frontal, parietal and temporal brain regions implicated in non-literal language processing. However, neurophysiological correlates of these brain areas underlying non-literal processing remain underexplored. To address this, we investigated patterns of intracranial EEG activity during non-literal processing by leveraging a unique patient population. Seven neurosurgical patients with invasive electrophysiological monitoring of superficial brain activity were recruited. Intracranial neural responses were recorded over the temporal-parietal junction (TPJ) and its surrounding areas while patients performed a language task. Participants listened to vignettes that ended with non-literal or literal statements and were then asked related questions to which they responded verbally. We found differential neurophysiological activity during the processing of non-literal statements as compared to literal statements, especially in low-Gamma (30-70 Hz) and delta (1-4 Hz) bands. In addition, we found that neural responses related to non-literal processing in the high-gamma band (>70 Hz) were significantly more prominent at TPJ electrodes as compared to non-TPJ (i.e., control) electrodes in most subjects. Moreover, in half of patients, high-gamma activity related to non-literal processing was accompanied by delta-band modulation. These results suggest that both low- and high-frequency electrophysiological activities in the temporal-parietal junction play a crucial role during non-literal language processing in the human brain. The current investigation, utilizing better spatial and temporal resolution of human intracranial electrocorticography, provides a unique opportunity to gain insights into the localized brain dynamics of the TPJ during the processing of non-literal language expressions.