Wireless Performance of a Fully Passive Neurorecording Microsystem Embedded in Dispersive Human Head Phantom

This paper reports the wireless performance of a biocompatible fully passive microsystem implanted in phantom media simulating the dispersive dielectric properties of the human head, for potential application in recording cortical neuropotentials. Fully passive wireless operation is achieved by means of backscattering electromagnetic (EM) waves carrying 3rd order harmonic mixing products (2f(sub 0) plus or minus f(sub m)=4.4-4.9 GHZ) containing targeted neuropotential signals (fm approximately equal to 1-1000 Hz). The microsystem is enclosed in 4 micrometer thick parylene-C for biocompatibility and has a footprint of 4 millimeters x 12 millimeters x 500 micrometers. Preliminary testing of the microsystem implanted in the lossy biological simulating media results in signal-to-noise ratio's (SNR) near 22 (SNR approximately equal to 38 in free space) for millivolt level neuropotentials, demonstrating the potential for fully passive wireless microsystems in implantable medical applications

Long-term dopamine neurochemical monitoring in primates

Many debilitating neuropsychiatric and neurodegenerative disorders are characterized by dopamine neurotransmitter dysregulation. Monitoring subsecond dopamine release accurately and for extended, clinically relevant timescales is a critical unmet need. Especially valuable has been the development of electrochemical fast-scan cyclic voltammetry implementing microsized carbon fiber probe implants to record fast millisecond changes in dopamine concentrations. Nevertheless, these well-established methods have only been applied in primates with acutely (few hours) implanted sensors. Neurochemical monitoring for long timescales is necessary to improve diagnostic and therapeutic procedures for a wide range of neurological disorders. Strategies for the chronic use of such sensors have recently been established successfully in rodents, but new infrastructures are needed to enable these strategies in primates. Here we report an integrated neurochemical recording platform for monitoring dopamine release from sensors chronically implanted in deep brain structures of nonhuman primates for over 100 days, together with results for behavior-related and stimulation-induced dopamine release. From these chronically implanted probes, we measured dopamine release from multiple sites in the striatum as induced by behavioral performance and reward-related stimuli, by direct stimulation, and by drug administration. We further developed algorithms to automate detection of dopamine. These algorithms could be used to track the effects of drugs on endogenous dopamine neurotransmission, as well as to evaluate the long-term performance of the chronically implanted sensors. Our chronic measurements demonstrate the feasibility of measuring subsecond dopamine release from deep brain circuits of awake, behaving primates in a longitudinally reproducible manner. Keywords: striatum; voltammetry; neurotransmitters; chronic implantsNational Institute of Neurological Diseases and Stroke (U.S.) (Grant R01 NS025529)National Institute of Neurological Diseases and Stroke (U.S.) (Grant F32 NS093897)United States. Army Research Office (Contract W911NF-16-1-0474)National Institute of Biomedical Imaging and Bioengineering (U.S.) (Grant R01 EB016101

A color detection glove with haptic feedback for the visually disabled

The following paper describes the design and preliminary results of a compact color detecting and feedback system. The device is intended for use by those with vision-loss or disabilities who may benefit by a means of perceiving color. The device consists of a glove incorporating optical color sensors along with tactile switches affixed to the fingertips, a haptic feedback interface wrapped around the fore arm, and a microprocessor unit to control communication between sensing and feedback. The color data and finger selection is encoded to spatial and temporal parameters on tactors. The study extends on earlier investigations by Tapson et. al. that have successfully demonstrated the capability of accurately identifying colors through haptic feedback. To further extend the field, the present research attempts to characterize color information in a temporally and spatially continuous representation to more realistically map the features of color space, and allow higher resolution of color perception

Wireless multichannel acquisition of neuropotentials

Abstract—Implantable brain-machine interfaces for disease diagnosis and motor prostheses control require low-power acquisition of neuropotentials spanning a wide range of amplitudes and frequencies. Here, we present a 16-channel VLSI neuropotential acquisition system with tunable gain and bandwidth, and variable rate digital transmission over an inductive link which further supplies power. The neuropotential interface chip is composed of an amplifier, incremental ADC and bit-serial readout circuitry. The front-end amplifier has a midband gain of 40 dB and offers NEF of less than 3 for all bandwidth settings. It also features adjustable low-frequency cut-off from 0.2 to 94 Hz, and independent high-frequency cut-off from 140 Hz to 8.2 kHz. The Gm-C incremental ∆Σ ADC offers digital gain up to 4096 and 8-12 bits resolution. The interface circuit is powered by a telemetry chip which harvests power through inductive coupling from a 4 MHz link, provides a 1 MHz clock for ADC operation and transmits the bit-serial data of the neurpotential interface across 4 cm at up to 32 kbps with a BER less than 10 −5. Experimental EEG recordings using the neuropotential interface and wireless module are presented. I

The prevalence of chronic pain in adolescents in Central Switzerland: A cross- sectional school-based study protocol.

BackgroundChronic pain is associated with substantial personal suffering and societal costs and is a growing healthcare concern worldwide. While chronic pain has been extensively studied in adults, limited data exists on its prevalence and impact in adolescents. Understanding the prevalence and impact of chronic pain and pain beliefs in adolescents is crucial for developing effective prevention and treatment strategies. This study aims to estimate the prevalence, characteristics, and impact of chronic pain, and explore adolescents' knowledge and beliefs about pain.MethodsThis is an observational cohort study of school-going adolescents aged 11 to 17 years in Central Switzerland. The study will estimate the point prevalence, characteristics (location, intensity, frequency, duration) and impact (PROMIS Pediatric Short Form v2.0 -Pain Interference Scale, PPIS) of chronic pain in school-going adolescents. We will also measure and investigate pupils' beliefs about pain (Concept of Pain Inventory (COPI)). Data will be collected through manual and digital self-report questionnaires and from participants in primary, secondary, and high schools between September 2023 and January 2024.AnalysesThe primary analyses will utilise descriptive statistics to estimate the point prevalence, characteristics, and impact of chronic pain. Secondary analyses will analyse associations and correlations between chronic pain, impact of pain and beliefs about pain.OutcomesThis study will provide an estimate of the prevalence, characteristics and impact of chronic pain in adolescents in Central Switzerland and a measure of adolescents' understanding and beliefs about pain. In doing so, this study will provide insights into the scale of chronic pain as a public health concern. By understanding adolescents' pain beliefs and their influence on pain experience, this study can contribute to the development of educational approaches to enhance adolescents' knowledge and understanding of pain in order to optimise the prevention and treatment of chronic pain in adolescents. The findings may be useful to healthcare professionals and funders, policymakers, and researchers involved in the prevention, assessment, and treatment of pain in adolescents

For better comprehension, a translation into English has been prepared based on the original ethical approval; please see document S2 EthicsEng also provided as supporting information.

For better comprehension, a translation into English has been prepared based on the original ethical approval; please see document S2 EthicsEng also provided as supporting information.</p

The ethical approval for this study is available in German; please refer to document S1 EthicsGer provided as supporting information.

The ethical approval for this study is available in German; please refer to document S1 EthicsGer provided as supporting information.</p

In Vitro Hydrodynamic, Transient, and Overtime Performance of a Miniaturized Valve for Hydrocephalus

Reliable cerebrospinal fluid (CSF) draining methods are needed to treat hydrocephalus, a chronic debilitating brain disorder. Current shunt implant treatments are characterized by high failure rates that are to some extent attributed to their length and multiple components. The designed valve, made of hydrogel, steers away from such protracted schemes and intends to provide a direct substitute for faulty arachnoid granulations, the brain’s natural CSF draining valves, and restore CSF draining operations within the cranium. The valve relies on innate hydrogel swelling phenomena to strengthen reverse flow sealing at idle and negative pressures thereby alleviating common valve failure mechanisms. In vitro measurements display operation in range of natural CSF draining (cracking pressure, P[subscript T] ~ 1–110 mmH[subscript 2]O and outflow hydraulic resistance, R[subscript h] ~ 24–152 mmH[subscript 2]O/mL/min), with negligible reverse flow leakage (flow, Q[subscript O] > −10 µL/min). Hydrodynamic measurements and over-time tests under physically relevant conditions further demonstrate the valve’s operationally-reproducible properties and strengthen its validity for use as a chronic implant