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Sensors (Basel, Switzerland) Jun 2024Respiratory rate (RR) is a vital indicator for assessing the bodily functions and health status of patients. RR is a prominent parameter in the field of biomedical...
Respiratory rate (RR) is a vital indicator for assessing the bodily functions and health status of patients. RR is a prominent parameter in the field of biomedical signal processing and is strongly associated with other vital signs such as blood pressure, heart rate, and heart rate variability. Various physiological signals, such as photoplethysmogram (PPG) signals, are used to extract respiratory information. RR is also estimated by detecting peak patterns and cycles in the signals through signal processing and deep-learning approaches. In this study, we propose an end-to-end RR estimation approach based on a third-generation artificial neural network model-spiking neural network. The proposed model employs PPG segments as inputs, and directly converts them into sequential spike events. This design aims to reduce information loss during the conversion of the input data into spike events. In addition, we use feedback-based integrate-and-fire neurons as the activation functions, which effectively transmit temporal information. The network is evaluated using the BIDMC respiratory dataset with three different window sizes (16, 32, and 64 s). The proposed model achieves mean absolute errors of 1.37 ± 0.04, 1.23 ± 0.03, and 1.15 ± 0.07 for the 16, 32, and 64 s window sizes, respectively. Furthermore, it demonstrates superior energy efficiency compared with other deep learning models. This study demonstrates the potential of the spiking neural networks for RR monitoring, offering a novel approach for RR estimation from the PPG signal.
Topics: Humans; Respiratory Rate; Neural Networks, Computer; Photoplethysmography; Signal Processing, Computer-Assisted; Heart Rate; Algorithms; Deep Learning
PubMed: 38931763
DOI: 10.3390/s24123980 -
Sensors (Basel, Switzerland) Jun 2024Sensor-based assessments in medical practice and rehabilitation include the measurement of physiological signals such as EEG, EMG, ECG, heart rate, and NIRS, and the...
Sensor-based assessments in medical practice and rehabilitation include the measurement of physiological signals such as EEG, EMG, ECG, heart rate, and NIRS, and the recording of movement kinematics and interaction forces. Such measurements are commonly employed in clinics with the aim of assessing patients' pathologies, but so far some of them have found full exploitation mainly for research purposes. In fact, even though the data they allow to gather may shed light on physiopathology and mechanisms underlying motor recovery in rehabilitation, their practical use in the clinical environment is mainly devoted to research studies, with a very reduced impact on clinical practice. This is especially the case for muscle synergies, a well-known method for the evaluation of motor control in neuroscience based on multichannel EMG recordings. In this paper, considering neuromotor rehabilitation as one of the most important scenarios for exploiting novel methods to assess motor control, the main challenges and future perspectives for the standard clinical adoption of muscle synergy analysis are reported and critically discussed.
Topics: Humans; Biomechanical Phenomena; Electromyography; Movement; Muscle, Skeletal
PubMed: 38931719
DOI: 10.3390/s24123934 -
Sensors (Basel, Switzerland) Jun 2024Photoplethysmography (PPG) is widely utilized in wearable healthcare devices due to its convenient measurement capabilities. However, the unrestricted behavior of users...
Photoplethysmography (PPG) is widely utilized in wearable healthcare devices due to its convenient measurement capabilities. However, the unrestricted behavior of users often introduces artifacts into the PPG signal. As a result, signal processing and quality assessment play a crucial role in ensuring that the information contained in the signal can be effectively acquired and analyzed. Traditionally, researchers have discussed signal quality and processing algorithms separately, with individual algorithms developed to address specific artifacts. In this paper, we propose a quality-aware signal processing mechanism that evaluates incoming PPG signals using the signal quality index (SQI) and selects the appropriate processing method based on the SQI. Unlike conventional processing approaches, our proposed mechanism recommends processing algorithms based on the quality of each signal, offering an alternative option for designing signal processing flows. Furthermore, our mechanism achieves a favorable trade-off between accuracy and energy consumption, which are the key considerations in long-term heart rate monitoring.
Topics: Photoplethysmography; Heart Rate; Humans; Signal Processing, Computer-Assisted; Algorithms; Monitoring, Physiologic; Wearable Electronic Devices
PubMed: 38931686
DOI: 10.3390/s24123901 -
Sensors (Basel, Switzerland) Jun 2024Well-being can reflect people's psychological conditions and be used alongside physiological parameters to evaluate patients' physical and mental health. The modern...
Well-being can reflect people's psychological conditions and be used alongside physiological parameters to evaluate patients' physical and mental health. The modern medical environment increasingly incorporates digital carriers, human-computer interaction devices, sensible spaces, and the execution of suitable algorithms. Slow design in healthy human-computer interaction is often used to reflect people's dependence on or support from behaviors or objects, promoting the stability of behaviors as well as meaningful and positive changes. Therefore, in this study, we propose a slow sensing model, develop a Slow Well-Being Gardening system, and use it to evaluate behavioral data from radiation therapy patients during treatment sessions and horticultural therapy. This study is based on SENS and slow design, setting the hospital lounge as a sensible space and establishing a sensor system. After a 10-day inspection, the process was evaluated and verified. Ultimately, data from facial detection (smile) and HRV showed that the patients in the experimental group experienced a significant improvement in their well-being, feeling better than those in the control group who maintained the most common state in normal treatment. Therefore, it can be inferred that the Slow Well-Being Gardening model is indeed valid and can be further developed.
Topics: Humans; Gardening; Horticultural Therapy; Female; Male; Algorithms; Middle Aged; Smiling; Heart Rate; Radiotherapy
PubMed: 38931555
DOI: 10.3390/s24123771 -
Sensors (Basel, Switzerland) Jun 2024The remote monitoring of vital signs via wearable devices holds significant potential for alleviating the strain on hospital resources and elder-care facilities. Among...
The remote monitoring of vital signs via wearable devices holds significant potential for alleviating the strain on hospital resources and elder-care facilities. Among the various techniques available, photoplethysmography stands out as particularly promising for assessing vital signs such as heart rate, respiratory rate, oxygen saturation, and blood pressure. Despite the efficacy of this method, many commercially available wearables, bearing Conformité Européenne marks and the approval of the Food and Drug Administration, are often integrated within proprietary, closed data ecosystems and are very expensive. In an effort to democratize access to affordable wearable devices, our research endeavored to develop an open-source photoplethysmographic sensor utilizing off-the-shelf hardware and open-source software components. The primary aim of this investigation was to ascertain whether the combination of off-the-shelf hardware components and open-source software yielded vital-sign measurements (specifically heart rate and respiratory rate) comparable to those obtained from more expensive, commercially endorsed medical devices. Conducted as a prospective, single-center study, the research involved the assessment of fifteen participants for three minutes in four distinct positions, supine, seated, standing, and walking in place. The sensor consisted of four PulseSensors measuring photoplethysmographic signals with green light in reflection mode. Subsequent signal processing utilized various open-source Python packages. The heart rate assessment involved the comparison of three distinct methodologies, while the respiratory rate analysis entailed the evaluation of fifteen different algorithmic combinations. For one-minute average heart rates' determination, the Neurokit process pipeline achieved the best results in a seated position with a Spearman's coefficient of 0.9 and a mean difference of 0.59 BPM. For the respiratory rate, the combined utilization of Neurokit and Charlton algorithms yielded the most favorable outcomes with a Spearman's coefficient of 0.82 and a mean difference of 1.90 BrPM. This research found that off-the-shelf components are able to produce comparable results for heart and respiratory rates to those of commercial and approved medical wearables.
Topics: Humans; Photoplethysmography; Respiratory Rate; Heart Rate; Software; Male; Signal Processing, Computer-Assisted; Female; Wearable Electronic Devices; Monitoring, Physiologic; Adult; Prospective Studies; Algorithms
PubMed: 38931550
DOI: 10.3390/s24123766 -
Sensors (Basel, Switzerland) Jun 2024Beach variants of popular sports like soccer and handball have grown in participation over the last decade. However, the characterization of the workload demands in... (Review)
Review
Beach variants of popular sports like soccer and handball have grown in participation over the last decade. However, the characterization of the workload demands in beach sports remains limited compared to their indoor equivalents. This systematic review aimed to: (1) characterize internal and external loads during beach invasion sports match-play; (2) identify technologies and metrics used for monitoring; (3) compare the demands of indoor sports; and (4) explore differences by competition level, age, sex, and beach sport. Fifteen studies ultimately met the inclusion criteria. The locomotive volumes averaged 929 ± 269 m (average) and 16.5 ± 3.3 km/h (peak) alongside 368 ± 103 accelerations and 8 ± 4 jumps per session. The impacts approached 700 per session. The heart rates reached 166-192 beats per minute (maximal) eliciting 60-95% intensity. The player load was 12.5 ± 2.9 to 125 ± 30 units. Males showed 10-15% higher external but equivalent internal loads versus females. Earlier studies relied solely on a time-motion analysis, while recent works integrate electronic performance and tracking systems, enabling a more holistic quantification. However, substantial metric intensity zone variability persists. Beach sports entail intermittent high-intensity activity with a lower-intensity recovery. Unstable surface likely explains the heightened internal strain despite moderately lower running volumes than indoor sports. The continued integration of technology together with the standardization of workload intensity zones is needed to inform a beach-specific training prescription.
Topics: Humans; Male; Female; Sports; Heart Rate; Athletic Performance; Bathing Beaches
PubMed: 38931522
DOI: 10.3390/s24123738 -
Sensors (Basel, Switzerland) Jun 2024Measuring pilot mental workload (MWL) is crucial for enhancing aviation safety. However, MWL is a multi-dimensional construct that could be affected by multiple factors.... (Review)
Review
Measuring pilot mental workload (MWL) is crucial for enhancing aviation safety. However, MWL is a multi-dimensional construct that could be affected by multiple factors. Particularly, in the context of a more automated cockpit setting, the traditional methods of assessing pilot MWL may face challenges. Heart rate variability (HRV) has emerged as a potential tool for detecting pilot MWL during real-flight operations. This review aims to investigate the relationship between HRV and pilot MWL and to assess the performance of machine-learning-based MWL detection systems using HRV parameters. A total of 29 relevant papers were extracted from three databases for review based on rigorous eligibility criteria. We observed significant variability across the reviewed studies, including study designs and measurement methods, as well as machine-learning techniques. Inconsistent results were observed regarding the differences in HRV measures between pilots under varying levels of MWL. Furthermore, for studies that developed HRV-based MWL detection systems, we examined the diverse model settings and discovered that several advanced techniques could be used to address specific challenges. This review serves as a practical guide for researchers and practitioners who are interested in employing HRV indicators for evaluating MWL and wish to incorporate cutting-edge techniques into their MWL measurement approaches.
Topics: Humans; Heart Rate; Workload; Machine Learning; Pilots; Aviation
PubMed: 38931507
DOI: 10.3390/s24123723 -
Nutrients Jun 2024Guarana (GUA), a Brazilian seed extract, contains caffeine and other bioactive compounds that may have psychoactive effects. To assess the acute effects of GUA compared... (Randomized Controlled Trial)
Randomized Controlled Trial
Guarana (GUA), a Brazilian seed extract, contains caffeine and other bioactive compounds that may have psychoactive effects. To assess the acute effects of GUA compared to a low dose of caffeine (CAF) on cognitive and mood parameters, twenty participants completed a double-blind, crossover experiment where they ingested capsules containing the following: (1) 100 mg CAF, (2) 500 mg GUA containing 130 mg caffeine, or (3) placebo (PLA). Cognitive tests (Simon and 2N-Back Task) were performed at the baseline (pre-ingestion) and 60 min after ingestion. The response time for the cognitive tests and heart rate variability were unaffected ( > 0.05) by treatment, although 2N-Back was overall faster ( = 0.001) across time. The accuracy in the 2N-Back Task showed a significant interaction effect ( = 0.029) due to higher post-ingestion versus pre-ingestion levels ( = 0.033), but only with the PLA. The supplements also had no effect on cognitive measures following physical fatigue ( = 11). There was an interaction effect on perceived mental energy, where the pre-ingestion of GUA had lower mental pep ratings compared to post-ingestion ( = 0.006) and post-exercise ( = 0.018) levels. Neither the acute ingestion of GUA nor low dose of CAF influenced cognitive performance or provided consistent benefit on mood or mental workload through vagal modulation. Additional investigations are beneficial to determining the lowest effective dose for CAF or GUA to influence mood and/or cognitive performance.
Topics: Humans; Caffeine; Paullinia; Male; Cross-Over Studies; Double-Blind Method; Cognition; Adult; Young Adult; Female; Heart Rate; Affect; Vagus Nerve; Plant Extracts; Dietary Supplements
PubMed: 38931247
DOI: 10.3390/nu16121892 -
Plants (Basel, Switzerland) Jun 2024(Laxm.) is a leguminous plant with significant ecological benefits, but its embryonic development mechanism remains unclear. We investigated the flower bud...
(Laxm.) is a leguminous plant with significant ecological benefits, but its embryonic development mechanism remains unclear. We investigated the flower bud differentiation, megaspore and microspore formation, gametophyte development, and embryo and endosperm development in . Our aim was to elucidate the relationship between the external morphology and internal development processes of male and female floral organs during growth, as well as the reproductive factors influencing fruiting. The results indicated that although the pistil develops later than the stamen during flower bud differentiation, both organs mature synchronously before flowering. pollen exhibits three germination grooves, a reticulate outer wall, and papillary structures on the anther surface. In vivo pollination experiments revealed abnormal spiral growth of pollen tubes within the style and the occurrence of callus plugs, which may reduce the seed setting rate. The anther wall development follows the dicotyledonous type, with tetrads formed through microspore meiosis exhibiting both left-right symmetry and tetrahedral arrangements. has a single ovule, and the embryo sac develops in the monosporic polygonum type. After dormancy, the zygote undergoes multiple divisions, progressing through spherical, heart-shaped, and torpedo-shaped embryo stages, culminating in a mature embryo. A mature seed comprises cotyledons, hypocotyl, embryo, radicle, and seed coat. Phylogenetic tree analysis reveals a close genetic relationship between and other leguminous plants from the genera and . This study provides valuable insights into the regulation of flowering and hybrid breeding in leguminous plants and offers a new perspective on the development of floral organs and seed setting rates.
PubMed: 38931095
DOI: 10.3390/plants13121661 -
Microorganisms Jun 2024When animals perceive an acute stressor like a predator, they typically undergo a suite of physiological changes that function to improve survival during the encounter,...
When animals perceive an acute stressor like a predator, they typically undergo a suite of physiological changes that function to improve survival during the encounter, such as elevation in cardiac output, to supply more energy to muscles. If bodily energy is limited, such as by parasites or infections, these functions could become less efficient and lessen host survival. In the aquatic world of microorganisms, individuals can become colonized by other organisms on their surface (epibionts), which could sap energy from their host from their weight, or even compete with the host for food. Here, we tested if one epibiont (a ciliated protozoan, spp.) affects its hosts' ability to mount a physiological stress reaction. We collected wild daphnia () that had varying burdens of these on their bodies and exposed them to a simulated stressor (crushed daphnia, to simulate nearby predation) under a microscope while monitoring for changes in their heart rates in real time. Out of 121 daphnia, those with no epibionts showed no meaningful changes in their heart rate after exposure, but those with light or heavy burdens showed immediate elevations (within 5 min). Moreover, the heart rates of heavily burdened daphnia continued to rise for 1.5 h thereafter, to as much as 17% higher than at baseline. These patterns were unexpected, as they suggest that the ciliated epibionts act to elevate their hosts' physiological reaction, rather than dampen it, perhaps by churning the water column around the host, thereby enhancing the chemical alarm cue. The procedures used in this study may be useful for future investigations into the acute stress reactions of daphnia or other microorganisms.
PubMed: 38930601
DOI: 10.3390/microorganisms12061219