SISTINE 3.0: Wearable System for Remote Functional Assessment of Phlebopathics

Phlebopathic diseases are chronic conditions that impact the health status and affect functional capacity. We developed SISTINE 3.0, a wearable system for remote monitoring of patients, and the aim of the study is to evaluate whether it can detect differences between participants with phlebology and healthy ones. Twelve patients and five healthy subjects performed a 3-metres Timed-Up-Go wearing SISTINE 3.0 system. The results support the system's potential to discriminate participants, especially based on the linear walking and turning angular velocity.

Wearable Electrochemical Glove-Based Analytical Device (eGAD) for the Detection of Methamphetamine Employing Silver Nanoparticles

Illicit drug misuse has become a widespread issue that requires continuous drug monitoring and diagnosis. Wearable electrochemical drug detection devices possess the potential to function as potent screening instruments in the possession of law enforcement personnel, aiding in the fight against drug trafficking and facilitating forensic investigations conducted on site. These wearable sensors are promising alternatives to traditional detection methods. In this study, we present a novel wearable electrochemical glove-based analytical device (eGAD) designed especially for detecting the club drug, methamphetamine. To develop this sensor, we immobilized meth aptamer onto silver nanoparticle (AgNPs)-modified electrodes that were printed onto latex gloves. The characteristics of AgNPs, including their shape, size and purity were analysed using FTIR, SEM and UV vis spectrometry, confirming the successful synthesis. The developed sensor shows a 0.1 µg/mL limit of detection and 0.3 µg/mL limit of quantification with a linear concentration range of about 0.01-5 µg/mL and recovery percentages of approximately 102 and 103%, respectively. To demonstrate its applicability, we tested the developed wearable sensor by spiking various alcoholic and non-alcoholic drink samples. We found that the sensor remains effective for 60 days, making it a practical option with a reasonable shelf-life. The developed sensor offers several advantages, including its affordability, ease of handling and high sensitivity and selectivity. Its portable nature makes it an ideal tool for rapid detection of METH in beverages too.

Nurses' Roles in mHealth App Development: Scoping Review

BACKGROUND

Although mobile health (mHealth) apps for both health consumers and health care providers are increasingly common, their implementation is frequently unsuccessful when there is a misalignment between the needs of the user and the app's functionality. Nurses are well positioned to help address this challenge. However, nurses' engagement in mHealth app development remains unclear.

OBJECTIVE

This scoping review aims to determine the extent of the evidence of the role of nurses in app development, delineate developmental phases in which nurses are involved, and to characterize the type of mHealth apps nurses are involved in developing.

METHODS

We conducted a scoping review following the 6-stage methodology. We searched 14 databases to identify publications on the role of nurses in mHealth app development and hand searched the reference lists of relevant publications. Two independent researchers performed all screening and data extraction, and a third reviewer resolved any discrepancies. Data were synthesized and grouped by the Software Development Life Cycle phase, and the app functionality was described using the IMS Institute for Healthcare Informatics functionality scoring system.

RESULTS

The screening process resulted in 157 publications being included in our analysis. Nurses were involved in mHealth app development across all stages of the Software Development Life Cycle but most frequently participated in design and prototyping, requirements gathering, and testing. Nurses most often played the role of evaluators, followed by subject matter experts. Nurses infrequently participated in software development or planning, and participation as patient advocates, research experts, or nurse informaticists was rare.

CONCLUSIONS

Although nurses were represented throughout the preimplementation development process, nurses' involvement was concentrated in specific phases and roles.

A Portable and a Scalable Multi-Channel Wireless Recording System for Wearable Electromyometrial Imaging

Electromyometrial imaging (EMMI) technology has emerged as one of the promising technology that can be used for non-invasive pregnancy risk stratification and for preventing complications due to pre-term birth. Current EMMI systems are bulky and require a tethered connection to desktop instrumentation, as a result, the system cannot be used in non-clinical and ambulatory settings. In this article, we propose an approach for designing a scalable, portable wireless EMMI recording system that can be used for in-home and remote monitoring. The wearable system uses a non-equilibrium differential electrode multiplexing approach to enhance signal acquisition bandwidth and to reduce the artifacts due to electrode drifts, amplifier 1/f noise, and bio-potential amplifier saturation. A combination of active shielding, a passive filter network, and a high-end instrumentation amplifier ensures sufficient input dynamic range ([Formula: see text]) such that the system can simultaneously acquire different bio-potential signals like maternal electrocardiogram (ECG) in addition to the EMMI electromyogram (EMG) signals. We show that the switching artifacts and the channel cross-talk introduced due to non-equilibrium sampling can be reduced using a compensation technique. This enables the system to be potentially scaled to a large number of channels without significantly increasing the system power dissipation. We demonstrate the feasibility of the proposed approach in a clinical setting using an 8-channel battery-powered prototype which dissipates less than 8 μW per channel for a signal bandwidth of 1 KHz.

Validation of photoplethysmography- and acceleration-based sleep staging in a community sample: comparison with polysomnography and Actiwatch

STUDY OBJECTIVES

Although wrist-worn consumer wearables are widely used for home sleep monitoring, few have been validated. It is unclear whether consumer wearables could be an alternative to Actiwatch. This study aimed to establish and validate an automatic sleep staging system (ASSS) utilizing photoplethysmography and acceleration data collected from a wrist-worn wearable device.

METHODS

Seventy-five participants from a community population underwent overnight polysomnography (PSG) while wearing a smartwatch (MT2511) and Actiwatch Spectrum Plus (Philips Respironics, Inc; Murrysville, PA, USA). Photoplethysmography and acceleration data collected from the smartwatches were utilized to build a 4-stage (wake, light sleep, deep sleep, and rapid eye movement [REM] sleep) classifier, which was validated against PSG. The performance of the sleep/wake classifier was compared with Actiwatch. All analyses were conducted separately for participants with PSG sleep efficiency (SE) ≥ 80% and SE < 80%.

RESULTS

The 4-stage classifier and PSG showed fair overall epoch-by-epoch agreement (kappa, 0.55; 95% confidence interval, 0.52 to 0.57). The deep sleep and REM times were comparable between ASSS and PSG, while ASSS underestimated the wake time and overestimated the light sleep time among participants with SE < 80%. Moreover, ASSS underestimated sleep-onset latency and wake after sleep onset and overestimated total sleep time and SE among participants with SE < 80%, while all were comparable among participants with SE ≥ 80%. The biases were smaller for ASSS than for Actiwatch.

CONCLUSIONS

Our photoplethysmography- and acceleration-based ASSS was reliable for participants with SE ≥ 80% and had a smaller bias than Actiwatch among those with SE < 80%. Thus, ASSS may be a promising alternative to Actiwatch.

CLINICAL TRIAL REGISTRATION

Registry: ClinicalTrials.gov; Name: Validation of Sleep Healthcare System; URL: https://clinicaltrials.gov/study/NCT04252482; Identifier: NCT04252482.

CITATION

Liu P-K, Ting N, Chiu H-C, et al. Validation of photoplethysmography- and acceleration-based sleep staging in a community sample: comparison with polysomnography and Actiwatch. J Clin Sleep Med. 2023;19(10):1797-1810.

Electrochemical Affinity Biosensors: Pervasive Devices with Exciting Alliances and Horizons Ahead

Electrochemical affinity biosensors are evolving at breakneck speed, strengthening and colonizing more and more niches and drawing unimaginable roadmaps that increasingly make them protagonists of our daily lives. They achieve this by combining their intrinsic attributes with those acquired by leveraging the significant advances that occurred in (nano)materials technology, bio(nano)materials and nature-inspired receptors, gene editing and amplification technologies, and signal detection and processing techniques. The aim of this Perspective is to provide, with the support of recent representative and illustrative literature, an updated and critical view of the repertoire of opportunities, innovations, and applications offered by electrochemical affinity biosensors fueled by the key alliances indicated. In addition, the imminent challenges that these biodevices must face and the new directions in which they are envisioned as key players are discussed.

A Novel Sensor-Based Application for Home-Based Rehabilitation Can Objectively Measure Postoperative Outcomes following Anterior Cruciate Ligament Reconstruction

In order to successfully implement individualized patient rehabilitation and home-based rehabilitation programs, the rehabilitation process should be objectifiable, monitorable and comprehensible. For this purpose, objective measurements are required in addition to subjective measurement tools. Thus, the aim of this prospective, single-center clinical trial is the clinical validation of an objective, digital medical device (DMD) during the rehabilitation after anterior cruciate ligament reconstruction (ACLR) with regards to an internationally accepted measurement tool. Sixty-seven patients planned for primary ACLR (70:30% male-female, aged 25 years [21-32], IKDC-SKF 47 [31-60], Tegner Activity Scale 6 [4-7], Lysholm Score 57 [42-72]) were included and received physical therapy and the DMD after surgery. For clinical validation, combined measures of range of motion (ROM), coordination, strength and agility were assessed using the DMD in addition to patient-reported outcome measures (PROMs) at three and six months after ACLR. Significant correlations were detected for ROM (rs = 0.36-0.46, p < 0.025) and strength/agility via the single-leg vertical jump (rs = 0.43, p = 0.011) and side hop test (rs = 0.37, p = 0.042), as well as for coordination via the Y-Balance test (rs = 0.58, p ≤ 0.0001) regarding the IKDC-SKF at three months. Additionally, DMD test results for coordination, strength and agility (Y-Balance test (rs = 0.50, p = 0.008), side hop test (rs = 0.54, p = 0.004) and single-leg vertical jump (rs = 0.44, p = 0.018)) correlate significantly with the IKDC-SKF at six months. No adverse events related to the use of the sensor-based application were reported. These findings confirm the clinical validity of a DMD to objectively quantify knee joint function for the first time. This will have further implications for clinical and therapeutic decision making, quality control and monitoring of rehabilitation measures as well as scientific research.

Flexible Self-Powered Energy Systems Based on H2 O/Ni2+ Intercalated Nix V2 O5 ⋅ nH2 O

The development of portable electronic devices has created greater demands for multifunctional energy integration systems. Self-powered systems have gained widespread interest because they can collect and storage renewable environmental energy and provide stable electricity to electronic devices. Herein, we developed a flexible self-charging energy system, involving textile-based zinc-ion hybrid (ZIHC) and triboelectric nanogenerator (TENG), which demonstrates wearable, compatibility, lightweight and can quickly harvest and store energy. Nix V2 O5  ⋅ nH2 O (NVO) loaded on carbon cloth (CC) with Ni2+ /H2 O ions intercalated as the cathode was assembled with activated CC to form a ZIHC, which has a voltage range of 2.0 V and capacitance value of 267.1 mF cm-2 as well as good charge and discharge rates and excellent cycling stability. At the same time, the NVO/CC can be assembled with PDMS to form a TENG achieving a maximum instantaneous power of 18.5 mW cm-2 . The device can be flexibly worn over the body to continuously harvest and store biomechanical energy and charge the electronic wristwatch successfully. This work demonstrates great convenience and promising practical applications as sustainable flexible energy system for portable electronic devices.

The Dosing of Mobile-Based Just-in-Time Adaptive Self-Management Prompts for Caregivers: Preliminary Findings From a Pilot Microrandomized Study

BACKGROUND

Caregivers of people with chronic illnesses often face negative stress-related health outcomes and are unavailable for traditional face-to-face interventions due to the intensity and constraints of their caregiver role. Just-in-time adaptive interventions (JITAIs) have emerged as a design framework that is particularly suited for interventional mobile health studies that deliver in-the-moment prompts that aim to promote healthy behavioral and psychological changes while minimizing user burden and expense. While JITAIs have the potential to improve caregivers' health-related quality of life (HRQOL), their effectiveness for caregivers remains poorly understood.

OBJECTIVE

The primary objective of this study is to evaluate the dose-response relationship of a fully automated JITAI-based self-management intervention involving personalized mobile app notifications targeted at decreasing the level of caregiver strain, anxiety, and depression. The secondary objective is to investigate whether the effectiveness of this mobile health intervention was moderated by the caregiver group. We also explored whether the effectiveness of this intervention was moderated by (1) previous HRQOL measures, (2) the number of weeks in the study, (3) step count, and (4) minutes of sleep.

METHODS

We examined 36 caregivers from 3 disease groups (10 from spinal cord injury, 11 from Huntington disease, and 25 from allogeneic hematopoietic cell transplantation) in the intervention arm of a larger randomized controlled trial (subjects in the other arm received no prompts from the mobile app) designed to examine the acceptability and feasibility of this intensive type of trial design. A series of multivariate linear models implementing a weighted and centered least squares estimator were used to assess the JITAI efficacy and effect.

RESULTS

We found preliminary support for a positive dose-response relationship between the number of administered JITAI messages and JITAI efficacy in improving caregiver strain, anxiety, and depression; while most of these associations did not meet conventional levels of significance, there was a significant association between high-frequency JITAI and caregiver strain. Specifically, administering 5-6 messages per week as opposed to no messages resulted in a significant decrease in the HRQOL score of caregiver strain with an estimate of -6.31 (95% CI -11.76 to -0.12; P=.046). In addition, we found that the caregiver groups and the participants' levels of depression in the previous week moderated JITAI efficacy.

CONCLUSIONS

This study provides preliminary evidence to support the effectiveness of the self-management JITAI and offers practical guidance for designing future personalized JITAI strategies for diverse caregiver groups.

TRIAL REGISTRATION

ClinicalTrials.gov NCT04556591; https://clinicaltrials.gov/ct2/show/NCT04556591.

Digital Platform for Continuous Monitoring of Patients Using a Smartwatch: Longitudinal Prospective Cohort Study

BACKGROUND

Since the COVID-19 pandemic, there has been a boost in the digital transformation of the human society, where wearable devices such as a smartwatch can already measure vital signs in a continuous and naturalistic way; however, the security and privacy of personal data is a challenge to expanding the use of these data by health professionals in clinical follow-up for decision-making. Similar to the European General Data Protection Regulation, in Brazil, the Lei Geral de Proteção de Dados established rules and guidelines for the processing of personal data, including those used for patient care, such as those captured by smartwatches. Thus, in any telemonitoring scenario, there is a need to comply with rules and regulations, making this issue a challenge to overcome.

OBJECTIVE

This study aimed to build a digital solution model for capturing data from wearable devices and making them available in a safe and agile manner for clinical and research use, following current laws.

METHODS

A functional model was built following the Brazilian Lei Geral de Proteção de Dados (2018), where data captured by smartwatches can be transmitted anonymously over the Internet of Things and be identified later within the hospital. A total of 80 volunteers were selected for a 24-week follow-up clinical trial divided into 2 groups, one group with a previous diagnosis of COVID-19 and a control group without a previous diagnosis of COVID-19, to measure the synchronization rate of the platform with the devices and the accuracy and precision of the smartwatch in out-of-hospital conditions to simulate remote monitoring at home.

RESULTS

In a 35-week clinical trial, >11.2 million records were collected with no system downtime; 66% of continuous beats per minute were synchronized within 24 hours (79% within 2 days and 91% within a week). In the limit of agreement analysis, the mean differences in oxygen saturation, diastolic blood pressure, systolic blood pressure, and heart rate were -1.280% (SD 5.679%), -1.399 (SD 19.112) mm Hg, -1.536 (SD 24.244) mm Hg, and 0.566 (SD 3.114) beats per minute, respectively. Furthermore, there was no difference in the 2 study groups in terms of data analysis (neither using the smartwatch nor the gold-standard devices), but it is worth mentioning that all volunteers in the COVID-19 group were already cured of the infection and were highly functional in their daily work life.

CONCLUSIONS

On the basis of the results obtained, considering the validation conditions of accuracy and precision and simulating an extrahospital use environment, the functional model built in this study is capable of capturing data from the smartwatch and anonymously providing it to health care services, where they can be treated according to the legislation and be used to support clinical decisions during remote monitoring.

Movement Recognition through Inductive Wireless Links: Investigation of Different Fabrication Techniques

In this paper, an inductive wireless link for motion recognition is investigated. In order to validate the feasibility of a wearable implementation, the use of three different materials is analyzed: a thin copper wire, a conductive yarn, and a conductive non-woven fabric. Results from the application of the developed devices on an arm are reported and discussed. It is demonstrated that the proposed textile inductive resonant wireless links are well suited for developing a compact wearable system for joint flexion recognition.

Shortwave infrared diffuse optical wearable probe for quantification of water and lipid content in emulsion phantoms using deep learning

Significance

The shortwave infrared (SWIR, ∼900 to 2000 nm) holds promise for label-free measurements of water and lipid content in thick tissue, owed to the chromophore-specific absorption features and low scattering in this range. In vivo water and lipid estimations have potential applications including the monitoring of hydration, volume status, edema, body composition, weight loss, and cancer. To the best of our knowledge, there are currently no point-of-care or wearable devices available that exploit the SWIR wavelength range, limiting clinical and at-home translation of this technology.

Aim

To design and fabricate a diffuse optical wearable SWIR probe for water and lipid quantification in tissue.

Approach

Simulations were first performed to confirm the theoretical advantage of SWIR wavelengths over near infrared (NIR). The probe was then fabricated, consisting of light emitting diodes at three wavelengths (980, 1200, 1300 nm) and four source-detector (S-D) separations (7, 10, 13, 16 mm). In vitro validation was then performed on emulsion phantoms containing varying concentrations of water, lipid, and deuterium oxide (D2O). A deep neural network was developed as the inverse model for quantity estimation.

Results

Simulations indicated that SWIR wavelengths could reduce theoretical water and lipid extraction errors from ∼6% to ∼1% when compared to NIR wavelengths. The SWIR probe had good signal-to-noise ratio (>32  dB up to 10 mm S-D) and low drift (<1.1% up to 10 mm S-D). Quantification error in emulsion phantoms was 2.1±1.1% for water and -1.2±1.5% for lipid. Water estimation during a D2O dilution experiment had an error of 3.1±3.7%.

Conclusions

This diffuse optical SWIR probe was able to quantify water and lipid contents in vitro with good accuracy, opening the door to human investigations.

Magnetic Properties of Amorphous Ta/CoFeB/MgO/Ta Thin Films on Deformable Substrates with Magnetic Field Angle and Tensile Strain

Recently, the application of cobalt iron boron (CoFeB) thin films in magnetic sensors has been widely studied owing to their high magnetic moment, anisotropy, and stability. However, most of these studies were conducted on rigid silicon substrates. For diverse applications of magnetic and angle sensors, it is important to explore the properties of ferromagnetic thin films grown on nonrigid deformable substrates. In this study, representative deformable substrates (polyimide (PI), polyethylene naphthalate (PEN), and polydimethylsiloxane (PDMS)), which can be bent or stretched, were used to assess the in-plane magnetic field angle-dependent properties of amorphous Ta/CoFeB/MgO/Ta thin films grown on deformable substrates. The effects of substrate roughness, tensile stress, deformable substrate characteristics, and sputtering on magnetic properties, such as the coercive field (Hc), remanence over saturation magnetization (Mr/Ms), and biaxial characteristics, were investigated. This study presents an unconventional foundation for exploring deformable magnetic sensors capable of detecting magnetic field angles.

Microfluidic-Integrated Multimodal Wearable Hybrid Patch for Wireless and Continuous Physiological Monitoring

Despite extensive advances in wearable monitoring systems, most designs focus on the detection of physical parameters or metabolites and do not consider the integration of microfluidic channels, miniaturization, and multimodality. In this study, a combination of multimodal (biochemical and electrophysiological) biosensing and microfluidic channel-integrated patch-based wireless systems is designed and fabricated using flexible materials for improved wearability, ease of operation, and real-time and continuous monitoring. The reduced graphene oxide-based microfluidic channel-integrated glucose biosensor exhibits a good sensitivity of 19.97 (44.56 without fluidic channels) μA mM-1 cm-2 within physiological levels (10 μM-0.4 mM) with good long-term and bending stability. All the sensors in the patch are initially validated using sauna gown sweat-based on-body and real-time tests with five separate individuals who perspired three times each. Multimodal glucose and electrocardiogram (ECG) sensing, along with their real-time adjustment based on sweat pH and temperature fluctuations, optimize sensing accuracy. Laser-burned hierarchical MXene-polyvinylidene fluoride-based conductive carbon nanofiber-based dry ECG electrodes exhibit low skin contact impedance (40.5 kΩ cm2) and high-quality electrophysiological signals (signal-to-noise ratios = 23.4-32.8 dB). The developed system is utilized to accurately and wirelessly monitor the sweat glucose and ECG of a human subject engaged in physical exercise in real time.

A wearable 3D pressure sensor based on electrostatic self-assembly MXene/chitosan sponge and insulating PVP spacer

It has been shown that flexible pressure sensors may be used in many different contexts, including human-machine interaction, intelligent robots, and health monitoring. In this work, we create a 3D sponge piezoresistive pressure sensor using MXene, chitosan, polyurethane sponge, and polyvinyl pyrrolidone (MXene/CS/PU sponge/PVP), with the well-conductive MXene nanosheet serving as the force sensitive material. In particular, the mechanical strength and endurance of the sensor are enhanced by electrostatic self-assembly between the negatively charged MXene nanosheets and the positively charged CS/PU composite sponge skeleton. The insulating PVP nanowires (PVP-NWs) also decreases the device's initial current, increasing the sensor's sensitivity. These characteristics allow the pressure sensor to simultaneously have a high sensitivity (50.27 kPa-1for pressure below 7 kPa and 13.3 kPa-1for pressure between 7 and 16 kPa), a quick response time (160 ms), a short recovery time (130 ms), and excellent cycling stability (5000 cycles). Moreover, the sensor exhibits a waterproof performance, where the force-sensitive layer still works normally after cleaning. In practice, the sensor could detect a variety of human actions as well as the distribution of spatial pressure due to the above superior device performance.

Current trends in the development of electrochemical biosensor for detecting analytes from sweat

The need for wearable bioelectronics continues to grow, and this technology might significantly alter the medical field. In order to diagnose and treat a patient, conventional medicine takes a "reactive" approach and waits for symptoms to appear first. Therefore, it is preferable to progress toward continuous non-invasive wearable biomonitoring, a preventative strategy that may assist individuals in diagnosing or treating illnesses at the earliest stages, sometimes before any outward symptoms have appeared. Wearable physiological sensors, such as the Apple Watch and FitBit, have arrived on the market as a result of technology advances and have quickly become commonplace. However, few devices currently exist that can report directly on these biomarkers of relevance. This is mostly due to the challenges involved in real-time fluid sampling and generating correct readouts utilising extremely selective and sensitive sensors. Sweat is an excretory fluid that is only allowed to be used in order to reduce invasiveness, but this restriction places additional strain on sensors owing to the diluted concentration of the relevant biomarkers and the changes in pH, salinity, and other biophysical parameters that directly influence the read-out of real-time biosensors. Sweat is favoured amid slightly invasive biofluids due to its low concentration of interfering chemicals and the fact that it may be collected without touching the mucosal layers. This review offers a concise outline of the latest advances in sweat-based wearable sensors, their promise in healthcare monitoring, and the problems faced in analysis based on sweat.

Comparing the reliability of muscle oxygen saturation with common performance and physiological markers across cycling exercise intensity

Introduction

Wearable near-infrared spectroscopy (NIRS) measurements of muscle oxygen saturation (SmO2) demonstrated good test-retest reliability at rest. We hypothesized SmO2 measured with the Moxy monitor at the vastus lateralis (VL) would demonstrate good reliability across intensities. For relative reliability, SmO2 will be lower than volume of oxygen consumption (V̇O2) and heart rate (HR), higher than concentration of blood lactate accumulation ([BLa]) and rating of perceived exertion (RPE). We aimed to estimate the reliability of SmO2 and common physiological measures across exercise intensities, as well as to quantify within-participant agreement between sessions.

Methods

Twenty-one trained cyclists completed two trials of an incremental multi-stage cycling test with 5 min constant workload steps starting at 1.0 watt per kg bodyweight (W·kg-1) and increasing by 0.5 W kg-1 per step, separated by 1 min passive recovery intervals until maximal task tolerance. SmO2, HR, V̇O2, [BLa], and RPE were recorded for each stage. Continuous measures were averaged over the final 60 s of each stage. Relative reliability at the lowest, median, and highest work stages was quantified as intraclass correlation coefficient (ICC). Absolute reliability and within-subject agreement were quantified as standard error of the measurement (SEM) and minimum detectable change (MDC).

Results

Comparisons between trials showed no significant differences within each exercise intensity for all outcome variables. ICC for SmO2 was 0.81-0.90 across exercise intensity. ICC for HR, V̇O2, [BLa], and RPE were 0.87-0.92, 0.73-0.97, 0.44-0.74, 0.29-0.70, respectively. SEM (95% CI) for SmO2 was 5 (3-7), 6 (4-9), and 7 (5-10)%, and MDC was 12%, 16%, and 18%.

Discussion

Our results demonstrate good-to-excellent test-retest reliability for SmO2 across intensity during an incremental multi-stage cycling test. V̇O2 and HR had excellent reliability, higher than SmO2. [BLa] and RPE had lower reliability than SmO2. Muscle oxygen saturation measured by wearable NIRS was found to have similar reliability to V̇O2 and HR, and higher than [BLa] and RPE across exercise intensity, suggesting that it is appropriate for everyday use as a non-invasive method of monitoring internal load alongside other metrics.

Accuracy and Reliability of a Suite of Digital Measures of Walking Generated Using a Wrist-Worn Sensor in Healthy Individuals: Performance Characterization Study

BACKGROUND

Mobility is a meaningful aspect of an individual's health whose quantification can provide clinical insights. Wearable sensor technology can quantify walking behaviors (a key aspect of mobility) through continuous passive monitoring.

OBJECTIVE

Our objective was to characterize the analytical performance (accuracy and reliability) of a suite of digital measures of walking behaviors as critical aspects in the practical implementation of digital measures into clinical studies.

METHODS

We collected data from a wrist-worn device (the Verily Study Watch) worn for multiple days by a cohort of volunteer participants without a history of gait or walking impairment in a real-world setting. On the basis of step measurements computed in 10-second epochs from sensor data, we generated individual daily aggregates (participant-days) to derive a suite of measures of walking: step count, walking bout duration, number of total walking bouts, number of long walking bouts, number of short walking bouts, peak 30-minute walking cadence, and peak 30-minute walking pace. To characterize the accuracy of the measures, we examined agreement with truth labels generated by a concurrent, ankle-worn, reference device (Modus StepWatch 4) with known low error, calculating the following metrics: intraclass correlation coefficient (ICC), Pearson r coefficient, mean error, and mean absolute error. To characterize the reliability, we developed a novel approach to identify the time to reach a reliable readout (time to reliability) for each measure. This was accomplished by computing mean values over aggregation scopes ranging from 1 to 30 days and analyzing test-retest reliability based on ICCs between adjacent (nonoverlapping) time windows for each measure.

RESULTS

In the accuracy characterization, we collected data for a total of 162 participant-days from a testing cohort (n=35 participants; median observation time 5 days). Agreement with the reference device-based readouts in the testing subcohort (n=35) for the 8 measurements under evaluation, as reflected by ICCs, ranged between 0.7 and 0.9; Pearson r values were all greater than 0.75, and all reached statistical significance (P<.001). For the time-to-reliability characterization, we collected data for a total of 15,120 participant-days (overall cohort N=234; median observation time 119 days). All digital measures achieved an ICC between adjacent readouts of >0.75 by 16 days of wear time.

CONCLUSIONS

We characterized the accuracy and reliability of a suite of digital measures that provides comprehensive information about walking behaviors in real-world settings. These results, which report the level of agreement with high-accuracy reference labels and the time duration required to establish reliable measure readouts, can guide the practical implementation of these measures into clinical studies. Well-characterized tools to quantify walking behaviors in research contexts can provide valuable clinical information about general population cohorts and patients with specific conditions.

Multimodal nocturnal seizure detection in children with epilepsy: A prospective, multicenter, long-term, in-home trial

OBJECTIVE

There is a pressing need for reliable automated seizure detection in epilepsy care. Performance evidence on ambulatory non-electroencephalography-based seizure detection devices is low, and evidence on their effect on caregiver's stress, sleep, and quality of life (QoL) is still lacking. We aimed to determine the performance of NightWatch, a wearable nocturnal seizure detection device, in children with epilepsy in the family home setting and to assess its impact on caregiver burden.

METHODS

We conducted a phase 4, multicenter, prospective, video-controlled, in-home NightWatch implementation study (NCT03909984). We included children aged 4-16 years, with ≥1 weekly nocturnal major motor seizure, living at home. We compared a 2-month baseline period with a 2-month NightWatch intervention. The primary outcome was the detection performance of NightWatch for major motor seizures (focal to bilateral or generalized tonic-clonic [TC] seizures, focal to bilateral or generalized tonic seizures lasting >30 s, hyperkinetic seizures, and a remainder category of focal to bilateral or generalized clonic seizures and "TC-like" seizures). Secondary outcomes included caregivers' stress (Caregiver Strain Index [CSI]), sleep (Pittsburgh Quality of Sleep Index), and QoL (EuroQol five-dimension five-level scale).

RESULTS

We included 53 children (55% male, mean age = 9.7 ± 3.6 years, 68% learning disability) and analyzed 2310 nights (28 173 h), including 552 major motor seizures. Nineteen participants did not experience any episode of interest during the trial. The median detection sensitivity per participant was 100% (range = 46%-100%), and the median individual false alarm rate was .04 per hour (range = 0-.53). Caregiver's stress decreased significantly (mean total CSI score = 8.0 vs. 7.1, p = .032), whereas caregiver's sleep and QoL did not change significantly during the trial.

SIGNIFICANCE

The NightWatch system demonstrated high sensitivity for detecting nocturnal major motor seizures in children in a family home setting and reduced caregiver stress.

Development and Evaluation of a Wearable Simulator System

Background

Peer physical examination is a clinical teaching-learning approach used for decades because of the convenient sample of peers for practicing. However, this approach has limitations when learning to assess abnormalities and threatens psychologically safe learning. A wearable simulator system was designed for learning physical examination skills to minimize ethical and learning challenges.

Sample

The sample consisted of fifty prelicensure nursing students and ten faculty in an upper Midwest university.

Method

The wearable simulator was constructed into a vest with RFID tags and ribcage landmarks. An observational, evaluative design was used for participants to rate seven categories during a one-hour evaluation session of the wearable simulator worn by a standardized patient trained to portray an individual with pneumonia.

Results

Satisfaction was rated highly among participants. More than 80% of student participants indicated the wearable simulator promotes privacy and reduces embarrassment.

Conclusion

The wearable simulator system offers a promising teaching-learning alternative with scenario-specific auscultation and palpation feedback to provide a safe, repeatable, and consistent simulation experience.

Wearable Ion Sensors for the Detection of Sweat Ions Fabricated by Heat-Transfer Printing

Wearable ion sensors for the real-time monitoring of sweat biomarkers have recently attracted increasing research attention. Here, we fabricated a novel chloride ion sensor for real-time sweat monitoring. The printed sensor was heat-transferred onto nonwoven cloth, allowing for easy attachment to various types of clothing, including simple garments. Additionally, the cloth prevents contact between the skin and the sensor and acts as a flow path. The change in the electromotive force of the chloride ion sensor was -59.5 mTV/log CCl-. In addition, the sensor showed a good linear relationship with the concentration range of chloride ions in human sweat. Moreover, the sensor displayed a Nernst response, confirming no changes in the film composition due to heat transfer. Finally, the fabricated ion sensors were applied to the skin of a human volunteer subjected to an exercise test. In addition, a wireless transmitter was combined with the sensor to wirelessly monitor ions in sweat. The sensors showed significant responses to both sweat perspiration and exercise intensity. Thus, our research demonstrates the potential of using wearable ion sensors for the real-time monitoring of sweat biomarkers, which could significantly impact the development of personalized healthcare.