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

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

Braincubator : an incubation system to extend brain slice lifespan for use in neurophysiology

In vitro brain slice preparations are instrumental in developing our understanding of the nervous system. However, the current lifespan of an acute brain slice is limited to approximately 6-12 hours. This reduces potential experimentation time and leads to considerable waste of neural tissue. We have designed, developed and tested a novel incubation system capable of extending the lifespan of these brain slices. This is done by controlling the temperature and pH of the artificial cerebral spinal fluid in which the slices are incubated while continuously passing the fluid through a UVC filtration system. This system is capable of maintaining extremely low bacterial levels and significantly extending the brain slice lifespan to at least 24 hours. Brain slice viability was validated through electrophysiological recordings as well as live/dead cell assays

Blood Volume Monitor

Patent: A blood volume monitor includes a carrier mountable on a subject's body part. A measuring arrangement is mounted on the carrier. The measuring arrangement provides data relating to a change in volume of the body part, and outputs signals representative of the change. A control unit is in communication with the measuring arrangement to process data output by the measuring arrangement to determine, using the volume data, the volume of the body part and determines blood volume in the body part. The control unit uses the response signals received from the measuring arrangement and the determined volume of the part of the body to determine the blood volume

An electrodeless, wearable system for simultaneous monitoring of cardiac and respiratory function

Introduction: Complex interactions inextricably link the pulmonary and cardiovascular systems. It is unsurprising then that chronic diseases such as chronic obstructive pulmonary disease (COPD) and heart failure are prevalent comorbidities affecting a huge proportion of the world population. Distinguishing their overlapping physiological effects is difficult. As a result the ability to monitor both cardiac function and respiration in a non-intrusive manner would be of great benefit to clinicians and researchers alike. To address this need, we have developed an inexpensive wearable solution to monitor both cardiac and respiration volume. Methods: Four electoresistive bands were pre-calibrated and embedded in a t-shirt. A 1mA constant-current source was applied to each band and the applied voltage recorded at 1kHz using a 16-bit ADC. The circumference of each band was calculated and used to estimate sectional volumes as truncated cones. From this data both respiration and cardiac output in ml are extracted. Results: Volume traces clearly display the contribution the top, mid and low sections of the thorax to respiration. Cardiac output volume is also displayed following signal processing to remove the respiration signal. Conclusions: This preliminary work demonstrates that an electroresistive system as described has tremendous potential as a low-cost method of recording both respiration and cardiac output

Hemodynamic monitor for rapid, cost-effective assessment of peripheral vascular function

Peripheral vascular diseases affect hundreds of millions of people worldwide and are often symptomless and undiagnosed. Early diagnosis is crucial for effective treatment and reducing personal and economic costs, particularly where early treatment is geared towards preventing lower extremity amputation. New diagnostic tools are needed to enable this earlier intervention. We have developed a new low-cost, easy to use, non-invasive hemodynamic monitor, HeMo, to address this large and growing problem. Using a novel combination of impedance tomography and electrical volumetric measurements we can calculate real-time changes in peripheral blood volume. We believe that this work will lead to the availability of a fast, easy to use and cost-effective vascular assessment tool, dramatically shortening the time to diagnosis and subsequently intervention, dramatically improving the prognosis of affected patients

Evaluation of a single accelerometer based biofeedback system for real-time correction of neck posture in computer users

The worldwide adoption of computers is closely linked to increased prevalence in neck and shoulder pain. Many ergonomic interventions are available; however, the lifetime prevalence of neck pain is still estimated as high as 80%. This paper introduces a biofeedback system using a novel single accelerometer placement. This system allows the user to react and correct for movement into a position of bad posture. The addition of visual information provides artificial proprioceptive information on the cranial-vertebral angle. Six subjects were tested for 5 hours with and without biofeedback. All subjects had a significant decrease in the percentage of time spent in bad posture when using biofeedback