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Physiological Measurement Nov 2023Photoplethysmography is a key sensing technology which is used in wearable devices such as smartwatches and fitness trackers. Currently, photoplethysmography sensors are... (Review)
Review
Photoplethysmography is a key sensing technology which is used in wearable devices such as smartwatches and fitness trackers. Currently, photoplethysmography sensors are used to monitor physiological parameters including heart rate and heart rhythm, and to track activities like sleep and exercise. Yet, wearable photoplethysmography has potential to provide much more information on health and wellbeing, which could inform clinical decision making. This Roadmap outlines directions for research and development to realise the full potential of wearable photoplethysmography. Experts discuss key topics within the areas of sensor design, signal processing, clinical applications, and research directions. Their perspectives provide valuable guidance to researchers developing wearable photoplethysmography technology.
Topics: Photoplethysmography; Wearable Electronic Devices; Fitness Trackers; Signal Processing, Computer-Assisted; Heart Rate
PubMed: 37494945
DOI: 10.1088/1361-6579/acead2 -
Indian Journal of Pediatrics Aug 2023Lung function testing is an essential modality of investigation in children as it provides objective evidence of lung disease/health. With advances in technology,... (Review)
Review
Lung function testing is an essential modality of investigation in children as it provides objective evidence of lung disease/health. With advances in technology, various tests are available that can aid in the diagnosis of lung disease, assess the progression and response to therapy and document the lung development and evolving lung diseases in infants. This narrative review discusses lung function tests in infants and children. Currently, lung function tests can be performed in every age group, from neonates to the elderly. Spirometry and peak expiratory flow rate (PEFR) are the most employed tests in children more than six years of age. Spirometry helps diagnose and monitoring of both obstructive and restrictive diseases. There is a need for expertise to perform and interpret spirometry correctly. The forced oscillation technique (FOT) or impulse oscillometry (IOS) is done with tidal volume breathing and is feasible even in preschool children. Their utility is mainly restricted to asthma in children at present. Lung function tests can be performed in neonates, infants and children using infant pulmonary function test (PFT) equipment, although their availability is limited. Diffusion capacity for carbon monoxide (DLCO) is a valuable tool in restrictive lung diseases. Lung volumes can be assessed by body plethysmography and multiple washout technique. The latter can also assess lung clearance index. It is essential to perform and interpret the lung function test results correctly and correlate them with the clinical condition for optimum treatment and outcome.
Topics: Child, Preschool; Infant, Newborn; Infant; Humans; Aged; Oscillometry; Respiratory Function Tests; Lung; Asthma; Spirometry; Forced Expiratory Volume
PubMed: 37261706
DOI: 10.1007/s12098-023-04588-8 -
Sensors (Basel, Switzerland) Dec 2023This review outlines the latest methods and innovations for assessing arterial stiffness, along with their respective advantages and disadvantages. Furthermore, we... (Review)
Review
This review outlines the latest methods and innovations for assessing arterial stiffness, along with their respective advantages and disadvantages. Furthermore, we present compelling evidence indicating a recent growth in research focused on assessing arterial stiffness using photoplethysmography (PPG) and propose PPG as a potential tool for assessing vascular ageing in the future. Blood vessels deteriorate with age, losing elasticity and forming deposits. This raises the likelihood of developing cardiovascular disease (CVD), widely reported as the global leading cause of death. The ageing process induces structural modifications in the vascular system, such as increased arterial stiffness, which can cause various volumetric, mechanical, and haemodynamic alterations. Numerous techniques have been investigated to assess arterial stiffness, some of which are currently used in commercial medical devices and some, such as PPG, of which still remain in the research space.
Topics: Humans; Photoplethysmography; Vascular Stiffness; Cardiovascular Diseases; Aging; Arteries
PubMed: 38139728
DOI: 10.3390/s23249882 -
Journal of Neuroinflammation Dec 2023Acute hyperbaric O (HBO) therapy after spinal cord injury (SCI) can reduce inflammation and increase neuronal survival. To our knowledge, it is unknown if these benefits...
Acute hyperbaric O (HBO) therapy after spinal cord injury (SCI) can reduce inflammation and increase neuronal survival. To our knowledge, it is unknown if these benefits of HBO require hyperbaric vs. normobaric hyperoxia. We used a C4 lateralized contusion SCI in adult male and female rats to test the hypothesis that the combination of hyperbaria and 100% O (i.e. HBO) more effectively mitigates spinal inflammation and neuronal loss, and enhances respiratory recovery, as compared to normobaric 100% O. Experimental groups included spinal intact, SCI no O therapy, and SCI + 100% O delivered at normobaric pressure (1 atmosphere, ATA), or at 2- or 3 ATA. O treatments lasted 1-h, commenced within 2-h of SCI, and were repeated for 10 days. The spinal inflammatory response was assessed with transcriptomics (RNAseq) and immunohistochemistry. Gene co-expression network analysis showed that the strong inflammatory response to SCI was dramatically diminished by both hyper- and normobaric O therapy. Similarly, both HBO and normobaric O treatments reduced the prevalence of immunohistological markers for astrocytes (glial fibrillary acidic protein) and microglia (ionized calcium binding adaptor molecule) in the injured spinal cord. However, HBO treatment also had unique impacts not detected in the normobaric group including upregulation of an anti-inflammatory cytokine (interleukin-4) in the plasma, and larger inspiratory tidal volumes at 10-days (whole body-plethysmography measurements). We conclude that normobaric O treatment can reduce the spinal inflammatory response after SCI, but pressured O (i.e., HBO) provides further benefit.
Topics: Rats; Male; Female; Animals; Hyperbaric Oxygenation; Neuroinflammatory Diseases; Spinal Cord Injuries; Spinal Cord; Inflammation; Oxygen
PubMed: 38110993
DOI: 10.1186/s12974-023-02985-6 -
Journal of Neuroscience Methods Jul 2023Sleep apnea, the most widespread sleep-related breathing disorder (SBD), consists of recurrent episodes of breathing cessation during sleep. This condition can be... (Review)
Review
Sleep apnea, the most widespread sleep-related breathing disorder (SBD), consists of recurrent episodes of breathing cessation during sleep. This condition can be classified as either central (CSA) or obstructive (OSA) sleep apnea, with the latest being the most common and toxic. Due to the complexity of living organisms, animal models and, particularly, mice still represent an essential tool for the study of SBD. In the present review we first discuss the methodological pros and cons in the use of whole-body plethysmography to coupling respiratory and sleep measurements and to characterize CSA and OSA in mice; then, we draw an updated and objective picture of the methods used so far in the study of sleep apnea in mice. Most of the studies present in the literature used intermittent hypoxia to mimic OSA in mice and to investigate consequent pathological correlates. On the contrary, few studies using genetic manipulation or high-fat diets investigated the pathogenesis or potential treatments of sleep apnea. To date, mice lacking orexins, hemeoxygenase-2, monoamine oxidase A, Phox2b or Cdkl5 can be considered validated mouse models of sleep apnea. Moreover, genetically- or diet-induced obese mice, and mice recapitulating Down syndrome were proposed as OSA models. In conclusion, our review shows that despite the growing interest in the field and the need of new therapeutical approaches, technical complexity and inter-study variability strongly limit the availability of validated mouse of sleep apnea, which are essential in biomedical research.
Topics: Humans; Mice; Animals; Sleep Apnea, Obstructive; Sleep Apnea Syndromes; Sleep; Respiration; Disease Models, Animal
PubMed: 37459897
DOI: 10.1016/j.jneumeth.2023.109923 -
American Journal of Physiology.... Sep 2023Previous studies show that COVID-19 survivors have elevated muscle sympathetic nerve activity (MSNA), endothelial dysfunction, and aortic stiffening. However, the...
Previous studies show that COVID-19 survivors have elevated muscle sympathetic nerve activity (MSNA), endothelial dysfunction, and aortic stiffening. However, the neurovascular responses to mental stress and exercise are still unexplored. We hypothesized that COVID-19 survivors, compared with age- and body mass index (BMI)-matched control subjects, exhibit abnormal neurovascular responses to mental stress and physical exercise. Fifteen severe COVID-19 survivors (aged: 49 ± 2 yr, BMI: 30 ± 1 kg/m) and 15 well-matched control subjects (aged: 46 ± 3 yr, BMI: 29 ± 1 kg/m) were studied. MSNA (microneurography), forearm blood flow (FBF), and forearm vascular conductance (FVC, venous occlusion plethysmography), mean arterial pressure (MAP, Finometer), and heart rate (HR, ECG) were measured during a 3-min mental stress (Stroop Color-Word Test) and during a 3-min isometric handgrip exercise (30% of maximal voluntary contraction). During mental stress, MSNA (frequency and incidence) responses were higher in COVID-19 survivors than in controls ( < 0.001), and FBF and FVC responses were attenuated ( < 0.05). MAP was similar between the groups ( > 0.05). In contrast, the MSNA (frequency and incidence) and FBF and FVC responses to handgrip exercise were similar between the groups ( > 0.05). MAP was lower in COVID-19 survivors ( < 0.05). COVID-19 survivors exhibit an exaggerated MSNA and blunted vasodilatory response to mental challenge compared with healthy adults. However, the neurovascular response to handgrip exercise is preserved in COVID-19 survivors. Overall, the abnormal neurovascular control in response to mental stress suggests that COVID-19 survivors may have an increased risk to cardiovascular events during mental challenge.
Topics: Adult; Humans; Middle Aged; Hand Strength; Blood Pressure; COVID-19; Hemodynamics; Exercise; Heart Rate; Sympathetic Nervous System; Forearm; Muscle, Skeletal
PubMed: 37449870
DOI: 10.1152/ajpregu.00111.2023 -
Journal of Neurodevelopmental Disorders Mar 2024Angelman syndrome (AS) is a rare neurodevelopmental disorder characterized by severe intellectual disability, little to no expressive speech, visual and motor problems,...
BACKGROUND
Angelman syndrome (AS) is a rare neurodevelopmental disorder characterized by severe intellectual disability, little to no expressive speech, visual and motor problems, emotional/behavioral challenges, and a tendency towards hyperphagia and weight gain. The characteristics of AS make it difficult to measure these children's functioning with standard clinical tests. Feasible outcome measures are needed to measure current functioning and change over time, in clinical practice and clinical trials.
AIM
Our first aim is to assess the feasibility of several functional tests. We target domains of neurocognitive functioning and physical growth using the following measurement methods: eye-tracking, functional Near-Infrared Spectroscopy (fNIRS), indirect calorimetry, bio-impedance analysis (BIA), and BOD POD (air-displacement plethysmography). Our second aim is to explore the results of the above measures, in order to better understand the AS phenotype.
METHODS
The study sample consisted of 28 children with AS aged 2-18 years. We defined an outcome measure as feasible when (1) at least 70% of participants successfully finished the measurement and (2) at least 60% of those participants had acceptable data quality. Adaptations to the test procedure and reasons for early termination were noted. Parents rated acceptability and importance and were invited to make recommendations to increase feasibility. The results of the measures were explored.
RESULTS
Outcome measures obtained with eye-tracking and BOD POD met the definition of feasibility, while fNIRS, indirect calorimetry, and BIA did not. The most important reasons for early termination of measurements were showing signs of protest, inability to sit still and poor/no calibration (eye-tracking specific). Post-calibration was often applied to obtain valid eye-tracking results. Parents rated the BOD POD als most acceptable and fNIRS as least acceptable for their child. All outcome measures were rated to be important. Exploratory results indicated longer reaction times to high salient visual stimuli (eye-tracking) as well as high body fat percentage (BOD POD).
CONCLUSIONS
Eye-tracking and BOD POD are feasible measurement methods for children with AS. Eye-tracking was successfully used to assess visual orienting functions in the current study and (with some practical adaptations) can potentially be used to assess other outcomes as well. BOD POD was successfully used to examine body composition.
TRIAL REGISTRATION
Registered d.d. 23-04-2020 under number 'NL8550' in the Dutch Trial Register: https://onderzoekmetmensen.nl/en/trial/23075.
Topics: Child; Humans; Angelman Syndrome; Reproducibility of Results; Body Composition; Plethysmography; Electric Impedance
PubMed: 38429713
DOI: 10.1186/s11689-024-09516-1