Assessment of the Factors Influencing the Recording Performance of Circumneural Electrodes.

The quality of recorded peripheral nerve signals is decisive for their application in therapies. The electroneurogram can be recorded via implantable circumeural electrodes that are wrapped around the peripheral nerve. The shape and amplitude of the signal recorded by the electrode are influenced by the design and contact configuration of the electrode.

Radio-frequency induced heating of intra-cranial EEG electrodes: The more the colder?

Many neurological disorders are analyzed and treated with implantable electrodes. Many patients with such electrodes have to undergo MRI examinations - often unrelated to their implant - at the risk of radio-frequency induced heating. The number of electrode contact sites of these implants keeps increasing due to improvements in manufacturing and computational algorithms.

The Fourth Bioelectronic Medicine Summit "Technology Targeting Molecular Mechanisms": current progress, challenges, and charting the future.

There is a broad and growing interest in Bioelectronic Medicine, a dynamic field that continues to generate new approaches in disease treatment. The fourth bioelectronic medicine summit "Technology targeting molecular mechanisms" took place on September 23 and 24, 2020. This virtual meeting was hosted by the Feinstein Institutes for Medical Research, Northwell Health.

Fabrication and validation of reference structures for the localization of subdural standard- and micro-electrodes in MRI.

Objective: Report simple reference structure fabrication and validate the precise localization of subdural micro- and standard electrodes in magnetic resonance imaging (MRI) in phantom experiments.

Approach: Electrode contacts with diameters of 0.3 mm and 4 mm are localized in 1.

Electrical connectors for neural implants: design, state of the art and future challenges of an underestimated component.

Unlabelled: Technological advances in electrically active implantable devices have increased the complexity of hardware design. In particular, the increasing number of stimulation and recording channels requires innovative approaches for connectors that interface electrodes with the implant circuitry.

Objective: This work aims to provide a common theoretical ground for implantable connector development with a focus on neural applications.

It's the little things: On the complexity of planar electrode heating in MRI.

Neurological disorders are increasingly analysed and treated with implantable electrodes, and patients with such electrodes are studied with MRI despite the risk of radio-frequency (RF) induced heating during the MRI exam. Recent clinical research suggests that electrodes with smaller diameters of the electrical interface between implant and tissue are beneficial; however, the influence of this electrode contact diameter on RF-induced heating has not been investigated. In this work, electrode contact diameters between 0.

A high risk of sleep apnea is associated with less postoperative cognitive dysfunction after intravenous anesthesia: results of an observational pilot study.

Background: The obstructive sleep apnea syndrome (OSAS) is characterized by temporary cerebral hypoxia which can cause cognitive dysfunction. On the other hand, hypoxia induced neurocognitive deficits are detectable after general anesthesia. The objective of this study was to evaluate the impact of a high risk of OSAS on the postoperative cognitive dysfunction after intravenous anesthesia.

Ten-year follow-up of a cemented tapered stem.

Introduction: This stem was cleared by the FDA in 2002 and has been implanted in cementless and cemented versions. Despite its long history, there are no long-term clinical  results available for the cemented version of this implant. The aim of this study was to provide such data.

Design of contact zone topography for implantable high-channel electrical connectors.

Detachable high-channel electrical connections pose a bottleneck on the path to active implants with higher numbers of electrode contacts and miniaturized geometries. Not only low-resistance, reproducible and reliable contacts have to be realized but also seals that ensure electrical insulation in the harsh body environment. Using planar contact arrangements one can resort to laser microprocessing leading to minimal size connectors.

Examiner effect on the objective structured clinical exam - a study at five medical schools.

Background: The Objective Structured Clinical Examination (OSCE) is increasingly used at medical schools to assess practical competencies. To compare the outcomes of students at different medical schools, we introduced standardized OSCE stations with identical checklists.

Methods: We investigated examiner bias at standardized OSCE stations for knee- and shoulder-joint examinations, which were implemented into the surgical OSCE at five different medical schools.

Investigation of serum Ki-67 as a biomarker in tumor-bearing dogs.

Because of the limited number of tumor markers in veterinary medicine, there is need for identifying new markers. Ki-67 has been investigated as a tissue marker of malignant alterations. We hypothesized that Ki-67 would also be measurable in serum and should therefore be elevated in cases of malignancy.

Influence of Anatomical Detail and Tissue Conductivity Variations in Simulations of Multi-Contact Nerve Cuff Recordings.

Accurate simulations of peripheral nerve recordings are needed to develop improved neuroprostheses. Previous models of peripheral nerves contained simplifications whose effects have not been investigated. We created a novel detailed finite element (FE) model of a peripheral nerve, and used it to carry out a sensitivity analysis of several model parameters.

An implantable ENG detector with in-system velocity selective recording (VSR) capability.

Detection and classification of electroneurogram (ENG) signals in the peripheral nervous system can be achieved by velocity selective recording (VSR) using multi-electrode arrays. This paper describes an implantable VSR-based ENG recording system representing a significant development in the field since it is the first system of its type that can record naturally evoked ENG and be interfaced wirelessly using a low data rate transcutaneous link. The system consists of two CMOS ASICs one of which is placed close to the multi-electrode cuff array (MEC), whilst the other is mounted close to the wireless link.

Algorithmic Summaries of Perioperative Blood Pressure Fluctuations.

Automated perioperative measurements such as cardiovascular monitoring data are commonly compared to established upper and lower thresholds, but could also allow for more complex interpretations. Analyzing such time series in extensive electronic medical records for research purposes may itself require customized automation, so we developed a set of algorithms for quantifying different aspects of temporal fluctuations. We implemented conventional measures of dispersion, summaries of absolute gradients between successive values, and Poincaré plots.

Using Arden Syntax for the Generation of Intelligent Intensive Care Discharge Letters.

Discharge letters are an important means of communication between physicians and nurses from intensive care units and their colleagues from normal wards. The patient data management system (PDMS) used at our local intensive care units provides an export tool to create discharge letters by inserting data items from electronic medical records into predefined templates. Local intensivists criticized the limitations of this tool regarding the identification and the further processing of clinically relevant data items for a flexible creation of discharge letters.

A randomized phase I trial evaluating the effects of inhaled 50-50% N2 O-O2 on remifentanil-induced hyperalgesia and allodynia in human volunteers.

Background: Opioids are known to relieve pain, and also aggravate pre-existing hyperalgesia. In animal studies, the N-methyl-d-aspartate-receptor antagonist nitrous oxide (N2 O) was able to prevent hyperalgesia. The present study evaluated the effect of N2 O on hyperalgesia after remifentanil infusion in healthy volunteers.

Non-hermetic encapsulation for implantable electronic devices based on epoxy.

Hermetic and non-hermetic implant packaging are the two strategies to protect electronic systems from the humid conditions inside the human body. Within the scope of this work twelve different material combinations for a non-hermetic, high-reliable epoxy based encapsulation technique were characterized. Three EPO-TEK (ET) epoxies and one low budget epoxy were chosen for studies with respect to their processability, water vapor transmission rate (WVTR) and adhesion to two different ceramic-based substrates as well as to one standard FR4-substrate.

Development of a multichannel implantable connector.

Further development of active implantable medical devices (AIMDs) coming along with higher channel counts and improved maintainability raises the requirements for implantable connectors in such systems. We developed a concept for an implantable multichannel connector. Contact pads manufactured by laser-structuring that are embedded into a silicone substrate serve as contact partners.

Selective inhibition of EGFR downstream signaling reverses the irradiation-enhanced migration of HNSCC cells.

Irradiation, which is one of the standard therapies used to treat squamous cell carcinoma of the head and neck (HNSCC), has been linked to enhanced tumor migration in carcinomas. In this study, we demonstrated that irradiation induced the phosphorylation of AKT, p38 MAPK and ERK. The combined activation of these pathways caused inactivation of GSK3β kinase, resulting in enhanced tumor cell migration.

Effect of TNF-alpha blockade on coagulopathy and endothelial cell activation in xenoperfused porcine kidneys.

Background: Following pig-to-primate kidney transplantation, endothelial cell activation and xenogenic activation of the recipient's coagulation eventually leading to organ dysfunction and microthrombosis can be observed. In this study, we examined the effect of a TNF-receptor fusion protein (TNF-RFP) on endothelial cell activation and coagulopathy utilizing an appropriate ex vivo perfusion system.

Methods: Using an ex vivo perfusion circuit based on C1-Inhibitor (C1-Inh) and low-dose heparin administration, we have analyzed consumptive coagulopathy following contact of human blood with porcine endothelium.

Competency in managing cardiac arrest: A scenario-based evaluation of dental students.

Objective: Advanced Cardiovascular Life Support (ACLS) in life-threatening situations is perceived as a basic skill for dental professionals. However, medical emergency training in dental schools is often not standardized. The dental students' knowledge transfer to an ACLS setting thus remains questionable.

Cuff electrodes for very small diameter nerves -- prototyping and first recordings in vivo.

A fabrication method for cuff electrodes to interface small nerves was developed. Medical grade silicone rubber conforms the body of the cuff and insulation of the wires, platinum was used as metal for the embedded wiring and contacts. Planar electrode arrays where fabricated using a picosecond laser and then positioned into a carrying tube to provide the third dimension with the desired inner diameter (Ø 0.

A polymer-metal two step sealing concept for hermetic neural implant packages.

In this paper, we introduce a technique for double-sealed ceramic packages for the long-term protection of implanted electronics against body fluids. A sequential sealing procedure consisting of a first step, during which the package is sealed with epoxy, protecting the implant electronics from aggressive flux fumes. These result from the application of the actual moisture barrier which is a metal seal applied in a second step by soft soldering.

Morphological and electrochemical properties of an explanted PtIr electrode array after 15 months in vivo.

We investigated the morphological and electrochemical properties of an explanted laser-machined 32 channel electrocorticogram (ECoG) electrode array made of platinum-iridium and silicone rubber. It was connected to a wireless brain-computer interface (BCI) and implanted in a sheep for more than 15 months. Recordings and stimulations of cortical activity were conducted over the whole period on a regularly basis.

Inhibition of SphK1 reduces radiation-induced migration and enhances sensitivity to cetuximab treatment by affecting the EGFR / SphK1 crosstalk.

SphK1 is known to play a role in tumor progression, resistance to radiochemotherapy, and migration patterns. As the overall survival rates of squamous cell carcinoma of the head and neck (HNSCC) remain poor due to limitations in surgery and irradiation and chemotherapy resistance, SphK1 is an important enzyme to investigate. The purpose of this study was to elucidate the impact of SphK1 on irradiation efficacy of HNSCC in-vitro with emphasis on EGFR signaling.