Continuous vital monitoring during sleep and light activity using carbon-black elastomer sensors

The comfortable, continuous monitoring of vital parameters is still a challenge. The long-term measurement of respiration and cardiovascular signals is required to diagnose cardiovascular and respiratory diseases. Similarly, sleep quality assessment and the recovery period following acute treatments require long-term vital parameter datalogging. To address these requirements, we have developed “VitalCore”, a wearable continuous vital parameter monitoring device in the form of a T-shirt targeting the uninterrupted monitoring of respiration, pulse, and actigraphy. VitalCore uses polymer-based stretchable resistive bands as the primary sensor to capture breathing and pulse patterns from chest expansion. The carbon black-impregnated polymer is implemented in a U-shaped configuration and attached to the T-shirt with “interfacing” material along with the accompanying electronics. In this paper, VitalCore is bench tested and compared to gold standard respiration and pulse measurements to verify its functionality and further to assess the quality of data captured during sleep and during light exercise (walking). We show that these polymer-based sensors could identify respiratory peaks with a sensitivity of 99.44%, precision of 96.23%, and false-negative rate of 0.557% during sleep. We also show that this T-shirt configuration allows the wearer to sleep in all sleeping positions with a negligible difference of data quality. The device was also able to capture breathing during gait with 88.9%–100% accuracy in respiratory peak detection

Low-power transcutaneous current stimulator for wearable applications

BACKGROUND: Peripheral neuropathic desensitization associated with aging, diabetes, alcoholism and HIV/AIDS, affects tens of millions of people worldwide, and there is little or no treatment available to improve sensory function. Recent studies that apply imperceptible continuous vibration or electrical stimulation have shown promise in improving sensitivity in both diseased and healthy participants. This class of interventions only has an effect during application, necessitating the design of a wearable device for everyday use. We present a circuit that allows for a low-power, low-cost and small form factor implementation of a current stimulator for the continuous application of subthreshold currents. RESULTS: This circuit acts as a voltage-to-current converter and has been tested to drive + 1 to - 1 mA into a 60 k[Formula: see text] load from DC to 1 kHz. Driving a 60 k[Formula: see text] load with a 2 mA peak-to-peak 1 kHz sinusoid, the circuit draws less than 21 mA from a 9 V source. The minimum operating current of the circuit is less than 12 mA. Voltage compliance is ± 60 V with just 1.02 mA drawn by the high voltage current drive circuitry. The circuit was implemented as a compact 46 mm × 21 mm two-layer PCB highlighting its potential for use in a body-worn device. CONCLUSIONS: No design to the best of our knowledge presents comparably low quiescent power with such high voltage compliance. This makes the design uniquely appropriate for low-power transcutaneous current stimulation in wearable applications. Further development of driving and instrumentation circuitry is recommended

Impact of galvanic vestibular stimulation-induced stochastic resonance on the output of the vestibular system : a systematic review

With an ageing population, techniques to improve balance function are necessary and likely to reduce the risk of falling due to age-related vestibular dysfunction. Previous work has shown that Galvanic Vestibular Stimulation (GVS) improves balance function in regards to vestibular output measures including Centre of Pressure (CoP) sway and Ocular Vestibular Evoked Myogenic Potentials (oVEMPs). Presumably these improvements are due to the modulation of primary vestibular afferents and vestibular hair cells, possibly via the phenomenon of Stochastic Resonance (SR). Specifically, SR is defined by the application of low-level noise which increases the detectability of subthreshold signals in non-linear systems, including the vestibular system. Major limitations to determining the most effective therapeutic approach to improve balance function using GVS-induced SR are the limited number of studies assessing the direct impact of GVS on vestibular function, and the heterogeneity of reported GVS stimulus parameters used. Indeed, there is a near complete paucity of comparative investigations between the major types of GVS including stochastic and white noise stimuli. Thus, the question arises - whether an optimal set of stimulus parameters to improve vestibular output can be ascertained from the currently available data? We conducted a systematic appraisal of the literature regarding the impact of GVS on vestibular function in healthy individuals as a means for answering this question

The Apple Watch for monitoring mental health–related physiological symptoms : literature review

Background: An anticipated surge in mental health service demand related to COVID-19 has motivated the use of novel methods of care to meet demand, given workforce limitations. Digital health technologies in the form of self-tracking technology have been identified as a potential avenue, provided sufficient evidence exists to support their effectiveness in mental health contexts. Objective: This literature review aims to identify current and potential physiological or physiologically related monitoring capabilities of the Apple Watch relevant to mental health monitoring and examine the accuracy and validation status of these measures and their implications for mental health treatment. Methods: A literature review was conducted from June 2021 to July 2021 of both published and gray literature pertaining to the Apple Watch, mental health, and physiology. The literature review identified studies validating the sensor capabilities of the Apple Watch. Results: A total of 5583 paper titles were identified, with 115 (2.06%) reviewed in full. Of these 115 papers, 19 (16.5%) were related to Apple Watch validation or comparison studies. Most studies showed that the Apple Watch could measure heart rate acceptably with increased errors in case of movement. Accurate energy expenditure measurements are difficult for most wearables, with the Apple Watch generally providing the best results compared with peers, despite overestimation. Heart rate variability measurements were found to have gaps in data but were able to detect mild mental stress. Activity monitoring with step counting showed good agreement, although wheelchair use was found to be prone to overestimation and poor performance on overground tasks. Atrial fibrillation detection showed mixed results, in part because of a high inconclusive result rate, but may be useful for ongoing monitoring. No studies recorded validation of the Sleep app feature; however, accelerometer-based sleep monitoring showed high accuracy and sensitivity in detecting sleep. Conclusions: The results are encouraging regarding the application of the Apple Watch in mental health, particularly as heart rate variability is a key indicator of changes in both physical and emotional states. Particular benefits may be derived through avoidance of recall bias and collection of supporting ecological context data. However, a lack of methodologically robust and replicated evidence of user benefit, a supportive health economic analysis, and concerns about personal health information remain key factors that must be addressed to enable broader uptake

Elastomeric pump infusion failures caused by inadequate Luer lock connector engagement to needleless connectors

Needleless connectors are used widely across all types of vascular access devices and provide safe, needleless administration of intravenous fluids and medications. An analysis of patients from an outpatient parenteral antimicrobial therapy program is presented in which elastomeric pumps had failed to flow due to incomplete tightening of Luer lock needleless connections. An alert was issued to community nursing staff responsible for daily elastomeric pump changes to ensure that needleless connectors were properly checked for full tightening. The frequency of failure of flow events before and after the alert was reviewed. Force and torque profiles required to activate the internal mechanism of connectors were measured in the 4 most frequently used needleless connectors in the outpatient parenteral antimicrobial therapy program. The degree of torque and force required to activate the different needleless connectors varied and was identified as a factor contributing to inadequate connection with the elastomeric pump and consequent failure of flow. Repeated feedback to nursing staff over the study period about the force and torque required for needleless connector flow activation resulted in a highly significant decrease in the rate of failure of flow events per elastomeric pump from a rate of 0.0147 events per elastomeric pump per year in the last 3 months of 2018 to 0.0003 in the first 6 months of 2020 (difference = 0.0144 [CI, 0.0097-0.02]; P < .0001)

Morphic sensors for respiratory parameters estimation : validation against overnight polysomnography

Effective monitoring of respiratory disturbances during sleep requires a sensor capable of accurately capturing chest movements or airflow displacement. Gold-standard monitoring of sleep and breathing through polysomnography achieves this task through dedicated chest/abdomen bands, thermistors, and nasal flow sensors, and more detailed physiology, evaluations via a nasal mask, pneumotachograph, and airway pressure sensors. However, these measurement approaches can be invasive and time-consuming to perform and analyze. This work compares the performance of a non-invasive wearable stretchable morphic sensor, which does not require direct skin contact, embedded in a t-shirt worn by 32 volunteer participants (26 males, 6 females) with sleep-disordered breathing who performed a detailed, overnight in-laboratory sleep study. Direct comparison of computed respiratory parameters from morphic sensors versus traditional polysomnography had approximately 95% (95 ± 0.7) accuracy. These findings confirm that novel wearable morphic sensors provide a viable alternative to non-invasively and simultaneously capture respiratory rate and chest and abdominal motions

Superconducting and normal-state properties of the noncentrosymmetric superconductor Re3Ta

The noncentrosymmetric superconductor, Re3Ta, has been characterized in detail with a combination of magnetization, heat capacity, and electrical resistivity measurements, as well as a microscopic investigation of the internal magnetic fields using muon spin spectroscopy (μSR). In low applied fields, we observe 100% flux expulsion at a temperature of Tc = 4.68 K, which is concomitant with a sudden decrease of the electrical resistivity to zero and a sharp discontinuity in the heat capacity, confirming bulk superconductivity in this material. We find that Re3Ta is a poor metal, with superconductivity occurring in the dirty limit, and in which the disorder in the structure dominates the physical properties. Zero-field μSR shows that the superconducting state preserves time-reversal symmetry, and transverse-field measurements of the superfluid density are well described by an isotropic s-wave model. A careful analysis of the internal field distribution reveals a high level of disorder in the vortex lattice. Furthermore, we have combined the experimental data and calculated the effective mass, carrier density, and electronic mean-free path in this material, and ultimately show that Re3Ta lies close to the unconventional region of the Uemura plot

Estimating survival in patients with gastrointestinal cancers and brain metastases: An update of the graded prognostic assessment for gastrointestinal cancers (GI-GPA).

BackgroundPatients with gastrointestinal cancers and brain metastases (BM) represent a unique and heterogeneous population. Our group previously published the Diagnosis-Specific Graded Prognostic Assessment (DS-GPA) for patients with GI cancers (GI-GPA) (1985-2007, n = 209). The purpose of this study is to update the GI-GPA based on a larger contemporary database.MethodsAn IRB-approved consortium database analysis was performed using a multi-institutional (18), multi-national (3) cohort of 792 patients with gastrointestinal (GI) cancers, with newly-diagnosed BM diagnosed between 1/1/2006 and 12/31/2017. Survival was measured from date of first treatment for BM. Multiple Cox regression was used to select and weight prognostic factors in proportion to their hazard ratios. These factors were incorporated into the updated GI-GPA.ResultsMedian survival (MS) varied widely by primary site and other prognostic factors. Four significant factors (KPS, age, extracranial metastases and number of BM) were used to formulate the updated GI-GPA. Overall MS for this cohort remains poor; 8 months. MS by GPA was 3, 7, 11 and 17 months for GPA 0-1, 1.5-2, 2.5-3.0 and 3.5-4.0, respectively. &gt;30% present in the worst prognostic group (GI-GPA of ≤1.0).ConclusionsBrain metastases are not uncommon in GI cancer patients and MS varies widely among them. This updated GI-GPA index improves our ability to estimate survival for these patients and will be useful for therapy selection, end-of-life decision-making and stratification for future clinical trials. A user-friendly, free, on-line app to calculate the GPA score and estimate survival for an individual patient is available at brainmetgpa.com

Cognitive decline and quality of life in incident Parkinson's disease: The role of attention.

INTRODUCTION: Parkinson's disease dementia (PDD) is associated with poorer quality of life (QoL). Prior to the onset of PDD, many patients experience progressive cognitive impairment. There is a paucity of longitudinal studies investigating the effects of cognitive decline on QoL. This study aimed to determine the longitudinal impact of cognitive change on QoL in an incident PD cohort. METHODS: Recently diagnosed patients with PD (n = 212) completed a schedule of neuropsychological assessments and QoL measures; these were repeated after 18 (n = 190) and 36 months (n = 158). Mild cognitive impairment (PD-MCI) was classified with reference to the Movement Disorder Society criteria. Principal component analysis was used to reduce 10 neuropsychological tests to three cognitive factors: attention, memory/executive function, and global cognition. RESULTS: Baseline PD-MCI was a significant contributor to QoL (β = 0.2, p < 0.01). For those subjects (9%) who developed dementia, cognitive function had a much greater impact on QoL (β = 10.3, p < 0.05). Multivariate modelling showed attentional deficits had the strongest predictive power (β = -2.3, p < 0.01); brief global tests only modestly predicted decline in QoL (β = -0.4, p < 0.01). CONCLUSIONS: PD-MCI was associated with poorer QoL over three years follow up. Cognitive impairment had a greater impact on QoL in individuals who developed dementia over follow-up. Impaired attention was a significant determinant of QoL in PD. Interventions which improve concentration and attention in those with PD could potentially improve QoL