Electrode Configurations for Electrical Bioimpedance-Based Pulse Wave Signal Acquisition: A Narrative Review

Flexible ferroelectric wearable devices for medical applications.

Electrical bioimpedance is based on the opposition exerted by body tissues to the passage of an electrical current. This characteristic allows the assessment of the individual's body composition, nutritional status, and hydration status. Electrical bioimpedance can be used to estimate body composition, health-related markers, general health status, diagnosis and prognostic of diseases, evaluation of treatment progress, and others. The aim of this study is to propose a methodology that allows us to integrate two methods of electrical bioimpedance analysis: bioelectrical impedance vector analysis, and bioelectrical impedance spectroscopy to evaluate the health of individuals.For methodology validation a retrospective clinical investigation was carried out where the data of healthy individuals and cancer patients included in the Database of the characterization of bioelectrical parameters by electrical Bioimpedance methods were analyzed.The values of electrical resistance and electrical reactance are higher in cancer patients compared to healthy individuals. However, the phase angle is lower in these patients. In the advanced stages of the disease, patients are located outside the tolerance ellipses. All these results are obtained at the characteristic frequency.The integration of bioelectrical impedance vector analysis, and bioelectrical impedance spectroscopy can be a sensitive complementary tool, capable of establishing differences between healthy individuals and cancer patients. Enrichment could be achieved by including the analysis of different physiological parameters through estimation equations validated by BIS parameters.

Electrode–skin impedance imbalance measured in the frequency domain

Objective: The bio-impedance (BI) of the body is a powerful parameter to assess the tissue composition and fluid content. Widespread implementation of BI measurement systems is limited due to the inability to detect, interpret and suppress frequently occurring artefacts during continuous use. A major proportion of the artefacts in BI measurements are caused at the skin electrode (SE) interface. Perturbations at the SE interface due to motion, applied pressure, temperature and posture change introduce distortions in the measured data which impede accurate interpretation for physiological monitoring. This paper investigates and accurately presents the effects of the aforementioned actions on the SE interface to develop effective algorithms for artefact identification and suppression at multiple frequencies in-field. Methods: Data collected from 20 subjects is used to analyze artefact associated features due to SE perturbations in BI measurements between 10kHz to 100kHz. Results: High variance noise, concept drifts and abrupt changes in measured BI baselines were identified as the main characteristics associated with artefacts due to SE interface perturbation. Artefacts were identified with a precision of upto 95% and a recall of upto 96% for all observed artefact labels. Conclusion: The characterization of artefacts due SE interface perturbations and high performance algorithms for artefact identification and suppression allow artefact free continuous monitoring of BI. Significance: The presented work enables continuous measurement of BI for non-invasive monitoring with wearable low power devices and permits accurate interpretation of many physiological processes, such as, edema onset, dehydration or urinary bladder filling, even in the presence of artefacts.

Monitoring of peripheral electrical bioimpedance (EBI) variations is a promising method that has potential to replace invasive or burdensome techniques for cardiovascular measurements. Segmental or continuous peripheral pulse recording can be substrate for calculating prognostic markers as pulse wave velocity (PWV) or can contain substrates as pulse transit time (PTT) or pulse arrival time (PAT) for undisturbing BP calculation or even new cardiovascular risk markers. Still several technical, analytical, and interpretative aspects need to be resolved before the EBI method can be adopted in clinical practice. Our goal was to investigate and improve application of the EBI, executing its comparison with other cardiovascular assessment methods in patients hospitalized for coronary catheterization procedure; Methods: We analyzed data from 44 non-acute patients aged 45-74 years hospitalized for coronary catheterization in East-Tallinn Central Hospital in 2020-2021. The radial EBI and ECG were measured simultaneously with contralateral radial and central pressure curves. The Savitzky–Golay filter was used for signal smoothing. The Hankel matrix decomposer for extraction of cardiac waveforms from the multi-component signals was applied. After extracting the cardiac component, a period detection algorithm was applied to EBI and blood pressure curves; Results: We were able to detect seven points on the pressure and EBI curves, five with good representativeness were selected for further analysis. Spearman correlation coefficient was low for all but the central and distal pressure curve systolic upstroke time points. High positive correlation was found between PWV measured both invasively and with EBI. High positive correlation was found between invasive and noninvasive PWV calculations. Median CPWV was significantly lower in patients with normal coronaries compared to patients with any stage of coronary disease; Conclusions: With regard to wearable devices, the EBI derived PAT can serve as a substrate to PWV calculations and cardiovascular risk assessment, although these data require further confirmation.

To evaluate the usefulness of transthoracic electrical bioimpedance in trending changes in cardiac output after cardiac surgery, and to identify predictors of differences between cardiac output measured by thermodilution and transthoracic electrical bioimpedance methods. Prospective repeated-measures study. University-affiliated tertiary care center. Thirty-four adult patients undergoing elective cardiac surgery with routine pulmonary artery catheter placement. Simultaneous paired cardiac output measurements by transthoracic electrical bioimpedance and thermodilution were made at four time points: within 2 hrs of intensive care unit (ICU) admission; when the patient reached a normothermic temperature; after extubation; and 24 hrs after ICU admission. Mean measurements by each method over time did not differ, except at ICU admission, when compared by repeated-measures analysis of variance. For each time point, bias and precision between methods were calculated. Bias calculations ranged from 0.02 to 0.21 L/min/m2. Precision calculations ranged from 1.06 to 1.52 L/min/m2. Predictors of between-method differences identified by a multiple regression model of hemodynamic variables were: increased systemic vascular resistance index, decreased mean arterial pressure (MAP), and the presence of atrial or ventricular pacing. While mean postoperative cardiac output measurements did not differ by method over time, agreement between transthoracic electrical bioimpedance and thermodilution methods was poor in the immediate postoperative period, with precision calculations indicative of clinically significant differences. Increased systemic vascular resistance index and decreased MAP were predictive of larger between-method differences.

Functional garments for physiological sensing purposes have been used in several disciplines, that is, sports, firefighting, military and medicine. In most of the cases, textile electrodes (textrodes) embedded in the garment are used to monitor vital signs and other physiological measurements. Electrical bioimpedance (EBI) is a non-invasive and effective technology that can be used for the detection and supervision of different health conditions.EBI technology could make use of the advantages of garment integration; however, a successful implementation of EBI technology depends on the good performance of textrodes. The main drawback of textrodes is a deficient skin-electrode interface that produces a high degree of sensitivity to signal disturbances. This sensitivity can be reduced with a suitable selection of the electrode material and an intelligent and ergonomic garment design that ensures an effective skin-electrode contact area. In this work, textrode functional straps for total right side EBI measurements for body composition are presented, and its measurement performance is compared against the use of Ag/AgCl electrodes. Shieldex sensor fabric and a tetra-polar electrode configuration using the ImpediMed spectrometer SFB7 in the frequency range of 3-500 kHz were used to obtain and analyse the impedance spectra and Cole and body composition parameters. The results obtained show stable and reliable measurements; the slight differences obtained with the functional garment do not significantly affect the computation of Cole and body composition parameters. The use of a larger sensor area, a high conductive material and an appropriate design can compensate, to some degree, for the charge transfer deficiency of the skin-electrode interface.

Owing to the increased public interest in passive brain–computer interface (pBCI) applications, many wearable devices for capturing electroencephalogram (EEG) signals in daily life have recently been released on the market. However, there exists no well-established criterion to determine the electrode configuration for such devices. Herein, an overall procedure is proposed to determine the optimal electrode configurations of wearable EEG devices that yield the optimal performance for intended pBCI applications. We utilized two EEG datasets recorded in different experiments designed to modulate emotional or attentional states. Emotion-specialized EEG headsets were designed to maximize the accuracy of classification of different emotional states using the emotion-associated EEG dataset, and attention-specialized EEG headsets were designed to maximize the temporal correlation between the EEG index and the behavioral attention index. General purpose electrode configurations were designed to maximize the overall performance in both applications for different numbers of electrodes (2, 4, 6, and 8). The performance was then compared with that of existing wearable EEG devices. Simulations indicated that the proposed electrode configurations allowed for more accurate estimation of the users’ emotional and attentional states than the conventional electrode configurations, suggesting that wearable EEG devices should be designed according to the well-established EEG datasets associated with the target pBCI applications.

1 - Coupling and electrodes

Introduction The concept of ‘wellbeing’ is typically thought of in human-centric ways, referring to the affective feelings and bodily sensations that people may have which inform their sense of health, safety, and connection. However, as our everyday lives, identities, relationships, and embodiments become digitised and datafied, ‘wellbeing’ has taken on new practices and meanings. The use of digital technologies such as mobile and wearable devices, social media platforms, and networks of information mediate our interactions with others, as well as the ways we conceptualise what it means to be human, including where the body begins and ends. In turn, digital health technologies and ‘wellness’ cultures such as those promoted on social media sites such as Instagram, Pinterest, YouTube, TikTok, and Facebook have also shaped our understanding of ‘wellness’ and ‘wellbeing’, their parameters, and how they ought to be practiced and felt (Baker; Lupton Digital Health; Lupton et al.). For millennia, aspects of human bodies have been documented and materialised in a variety of ways to help people understand states of health and illness: including relationships to the environments in which they lived. Indigenous and other non-Western cosmologies have long emphasised the kinds of vibrancies and distributed agencies that are part of reciprocal more-than-human ‘manifestings’ of kinships, and have called for all people to adopt the role of stewards of the ecosystem (Bawaka Country et al.; Hernández et al.; Kimmerer; Rots; Todd; Tynan). In Western cultures, ideas of the human body that reach back to ancient times adopt a perspective that viewed the continuous flows of forces (the four humours) in conjunction with the elements of air, wind, earth, and fire inside and outside the body as contributing to states of health or ill health. It was believed that good health was maintained by ensuring a balance between these factors, including acknowledgement of the role played by climactic, ecological, and celestial conditions (Hartnell; Lagay). A more-than-human approach is beginning to be re-introduced into Western cultures through political activism and academic thinking about the harms to the planet caused by human actions, including global warming and climate crises, loss of habitats and ecological biodiversity, increased incidence of extreme weather events such as bushfires, floods, and cyclones, and emerging novel pathogens affecting the health not only of humans but of other living things (Lewis; Lupton Covid Societies; Lupton Internet of Animals; Neimanis et al.). Contemporary Western more-than-human philosophers argue for the importance of acknowledging our kinship with other living and non-living things as a way of repositioning ourselves within the cosmos and working towards better health and wellbeing for the planet (Abram; Braidotti; Plumwood). As these approaches emphasise, health, wellbeing, and kinship are always imbricated within material-social assemblages of humans and non-digital things which are constantly changing, and thereby generating emergent rather than fixed capacities (Lupton "Human-Centric"; Lupton et al.). In this article, we describe our More-than-Human Wellbeing exhibition. To date, new media, Internet, and communication studies have not devoted as much attention to more-than-human theory. It is this more-than-digital and more-than-human approach to health information and wellbeing that marks out our research program as particularly distinctive. Our research focusses on the many and varied digital and non-digital forms that information about health and bodies takes. We are interested in health data as they are made and form part of the objects and activities of people’s everyday lives and aim to expand the human-centric approach offered in digital health by positioning human health and embodiment as always imbricated within more-than-human ecosystems. We acknowledge that all environments (natural and human-built) are intertwined with humans, and that to a greater or lesser extent, all are configured with and through the often exploitative and extractive practices and ideologies of those living in late modern societies in which people are positioned as superior to and autonomous from other living things. Together with more-than-human scholarship, we take inspiration from work in which arts-based, multisensory, and museum curation methods are employed to draw attention to the intertwining of people and ecologies (Endt-Jones; Howes). Our exhibition was planned as a research translation and engagement project, communicating several of our studies’ findings in arts-based media (Lupton "Embodying"). In what follows, we outline the concepts leading to the creation of our exhibits and describe how these pieces materialise and extend more-than-human concepts of wellbeing and care. Five of the exhibits we created for this exhibition are discussed. They all draw on our research findings across a range of studies, together with more-than-human theory and medical history (Lupton "More-Than-Human"). We describe how we used these pieces to materialise more-than-human concepts of health, wellbeing, and kinship in ways that we hoped would provoke critical thought, affective responses, and open capacities for action for contributing to both human and nonhuman flourishing. The background, thinking, and modes of making leading to the creation of ‘Cabinet of Human/Digital/Data Curiosities’, ‘Smartphone Fungi’, ‘Hand of Signs’, ‘Silken Anatomies’, and ‘Talking/Flowers’ are explained below. Bodily Curios Vaughan Wozniak-O’Connor and Deborah Lupton. Cabinet of Human/Digital/Data Curiosities. Reclaimed timber, found objects, resin 3D prints. 2023. Fig. 1: Cabinet of Human/Digital/Data Curiosities. Fig. 2: Detail from Cabinet of Human/Digital/Data Curiosities. The objects we have placed in Cabinet of Human/Digital/Data Curiosities (figs. 1 and 2) mix together such things from the past as prosthetic human eyeballs and teeth used in medicine and dentistry in earlier eras. This collection of found and manufactured objects, both old and new, draws on the concept of the ‘cabinet of curiosities’, also known as cabinets of wonder, which first became popular in the sixteenth century. Artefacts were assembled together for viewing in a room or a display case. The items were chosen for being notable in some way by the curator, including objects from natural history, antiquities, and religious relics, as well as works of art. These collections, purchased, curated, and assembled by members of the nobility or the wealthy as a marker of refinement, knowledge, or social status, were the precursor of museums (Endt-Jones). We see digital devices such as mobile phones as one of a multitude of ways that operate to document and preserve elements of human embodiment – indeed, as contemporary ‘cabinets of curiosities’. Our cabinet also refers to the tradition of medical museums, which display preserved human organs, body parts, and tissue in glass bottles for pedagogical purposes. Under this model of health, specimens of both ‘ideal’ health and also ‘ill’ health – abnormalities in the flesh – were documented as a means of categorising wellbeing. Museums such as these would often treat diseased and disabled bodies as oddities and artefacts of ‘curiosity’. In this work, we reimagine and wind back this way of thinking, through displaying and drawing attention and curiosity towards signs of the body and the everyday. We are showing that wellbeing is more than a process of categorisation, comparison, or measurement of ‘ideal’ or ‘abnormal’; it is in the traces we leave behind us when we return to the earth. Our information data are human remains, moving as endless constellations of the interior and exterior of the body (Lupton Data Selves). In this artwork, both reclaimed wood and 3D-printed resin were used as a synergy between the natural and synthetic. Taking our cue from the manner of display of these items in medical museums, we have added our own curios, including 3D-printed body organs sprouting fungi (fig. 2), as a way of demonstrating the entanglements between humans and the fungal kingdom. Interspersed among these relics of human bodies is a discarded mobile phone with its screen badly shattered. It is displayed as a more recent antiquated object for making images and collecting, storing, and displaying information and images about human bodies, which itself is subject to disastrous events despite its original high-tech veneer of glossy impermeability. Technologies are more-than-flesh as human-made simulacra of body parts. Our wellbeing is sensed and made sense of through bodies’ entanglements of human and nonhuman. These curios both materialise traces of our bodies and wellbeing and extend our bodies into the physical spaces we inhabit and through which we move. Reading the Traces and Signs Vaughan Wozniak-O’Connor and Deborah Lupton. Smartphone Fungi. Recycled European oak, 3D printed resin, CNC carved plywood. 2023 Vaughan Wozniak-O’Connor and Deborah Lupton. Hand of Signs. Laser-etched walnut and plywood. 2023. Fig. 3: Smartphone Fungi. / Fig. 4: Detail from Smartphone Fungi. Wellbeing is also a process of mark-making, realised through the reciprocal impressions we leave on each other and the world around us. In Smart Phone Fungi (figs. 3 and 4) we capture the idea of ‘recording’ that takes place between people, technologies, and the natural world. It was inspired by a huge tree which members of our team noticed on a bush walk in the Blue Mountains, near Sydney, Australia. Growing from this tree were fungi of similar size and shape to the smartphone that was used to capture the image. In our interpretation, a piece of reclaimed timber was used to represent the tree, itself marked by its human use, and fungal shapes replicating those on the tree were produced using computer numerical controlled (CNC) carving. The central timber

In recent years, Electrical Bioimpedance (EBI) methods have gained importance. These methods are often based on obtaining impedance spectrum in the range of β-dispersion, i.e. from a few kHz up to some MHz. To measure EBI a constant current is often injected and the voltage across the tissue under study is recorded. Due to the performance of the current source influences the performance of the entire system, in terms of frequency range, several designs have been implemented and studied. In this paper the basic structure of a Voltage-Controlled Current Source based on a single Op-Amp in inverter configuration with a floating load, known as load-in-the-loop current source, is revisited and studied deeply. We focus on the dependence of the output impedance with the circuit parameters, i.e. the feedback resistor and the inverter-input resistor, and the Op-Amp main parameters, i.e. open loop gain, CMRR and input impedance. After obtaining the experimental results, using modern Op-Amps, and comparing to the theoretical and simulated ones, they confirm the design under study can be a good solution for multi-frequency wideband EBI applications because of higher values of the output impedance than 100kΩ at 1MHz are obtained. Furthermore, an enhancement of the basic design, using a current conveyor as a first stage, is proposed, studied and implemented.

Over the past decades, wearable and implantable devices have demonstrated great potential for a wide range of personalized health monitoring and therapeutic applications. This special issue primarily focuses on functional and electronic materials, sensors technologies and capabilities, and the associated energy solutions for wearable and implantable devices toward healthcare applications. We have collected 17 reviews, four research articles, and one perspective, all of which are within the scope of this area and cover the topics in breadth and depth.

This chapter presents the research questions, approaches, and arguments of the book, asking how our everyday lives with media have changed after the smartphone. I introduce the topic of media use in everyday life as an empirical, methodological, and theoretical research interest, and argue for its continued centrality to our digital society today, accentuated by datafication. I discuss how the analytical concepts of media repertories and public connection can inform research into media use in everyday life, and what it means that our societies and user practices are becoming more digital. The main argument of the book is that digital media transform our navigation across the domains of everyday life by blurring boundaries, intensifying dilemmas, and affecting our sense of connection to communities and people around us. The chapter concludes by presenting the structure of the rest of the book, where these arguments will be substantiated in analysis of media use an ordinary day, media use in life phase transitions, and media use when ordinary life is disrupted. Citation Ytre-Arne, B. (2023), "Introduction: Media Use and Everyday Life in Digital Societies", Media Use in Digital Everyday Life, Emerald Publishing Limited, Bingley, pp. 1-16. https://doi.org/10.1108/978-1-80262-383-320231001 Publisher: Emerald Publishing Limited Copyright © 2023 Brita Ytre-Arne License Published by Emerald Publishing Limited. This work is published under the Creative Commons Attribution (CC BY 4.0) licence. Anyone may reproduce, distribute, translate and create derivative works of this book (for both commercial and non-commercial purposes), subject to full attribution to the original publication and authors. The full terms of this licence may be seen at http://creativecommons.org/licences/by/4.0/legalcode. Can you remember your first smartphone, and did it change your life? I bought my first smartphone in the early summer of 2011, right before the birth of my first child. I can safely say that life was never the same again. Although the new phone was hardly the most significant change that happened, it became part of how I reconfigured everyday life. My coincidental timing of these events might be a personal particularity, but the early 2010s, only a little more than a decade ago, was a period in which smartphones became part of everyday life for lots of people. This happened in Norway where I live, and in other countries in the Global North, soon followed by broader proliferation worldwide (Avle et al., 2020). In 2021, it was estimated that more than 90 per cent of people had smartphone access in a growing number of countries around the globe (Deloitte, 2021). ‘Smartphones changed everything’, wrote the Wall Street Journal in 2020: ‘smartphones upended every element of society during the last decade, from dating to dinner parties, travel to politics. This is just the beginning’ (Kitchen, 9.9.2020). But while all of this was happening, people lived their lives, using smartphones along with other media old and new, interwoven with what was going on in their lives, and in the world around them. This book explores the role of media in our everyday lives in digital societies, after the proliferation of smartphones and in conditions of ubiquitous connectivity. I analyze everyday media use across platforms, content types and modes of communication, taking the perspective of how we live our lives with media – how we manage plans and practicalities, keep in touch with friends and family, seek information and entertainment, work and learn, take part in shared experiences, and connect to our social lifeworlds. We might do all of this in the space of one single day, and we might experience such a day as ‘ordinary’ – just normal everyday life. But media technologies are also part of our less ordinary days, important to how we manage life-changing transitions and special events in our personal lives, and to how we relate to local communities, political processes or global events. We use media to connect to each other, and to society – throughout an ordinary day, across the life course, and in times of disruption. The smartphone is emblematic of how our everyday lives with media are changing in a digital and hyper-connected society, and as such it is essential to the topic of this book. A central question I discuss is what it means that most of us now have a smartphone to reach for, from where we are and what we are doing, to manage multiple aspects of our daily lives: A mobile, flexible device we rely on to communicate, find information, entertain and assist us, often used in combination with other media, but also a device that enables tracking and surveillance of our movements and engagements, informing feedback loops based on our personal data. How has digital media use in everyday life changed after the smartphone? To answer these questions, I draw on classic scholarship on media and communication technologies in everyday life (Baym, 2015; Silverstone, 1994), and on recent analysis of digital ambivalence and disconnection (Syvertsen, 2020). With a user perspective, I situate smartphones and other kinds of digital platforms as part of broader media repertoires (Hasebrink & Hepp, 2017), with an interest in the totality and internal relationships of any kind of media that people use and find meaningful in their everyday lives. I further understand everyday media use as central to public connection (Couldry et al., 2010), to how we orient ourselves to a world beyond our private concerns. The book provides an updated perspective on media in everyday life after digital media has become increasingly embedded and ingrained in society. A purpose for the book is to fill a gap between classic (but old) discussions on everyday media use, and recent (but sometimes narrowly focused) studies of new technologies. Our understandings of everyday media use are still shaped by theories developed before the internet, before digital and social and mobile media. This book highlights rather than discards these understandings, but moves forward in tackling dilemmas of technological transformations, and by considering recent crises such as the COVID-19 pandemic. I untangle how media becomes meaningful to us in the everyday, connecting us to each other and to communities and publics. The book offers empirical, methodological and theoretical insight on media use in digital everyday life. Why Everyday Life? ‘Everyday life’ is one of those concepts that everyone understands, but which is still difficult to define. The term is not internal jargon belonging to a particular research field, but instead recognizable across a range of contexts – we might even describe it as an ‘everyday’ term. One of the early ideas behind this book was to answer the questions: ‘But what do you mean by everyday life?’ and further ‘Why do you [meaning media use researchers] go on about everyday life?’. These are good questions. Let us start with the latter: Why everyday life? More precisely, why would someone interested in media use find it important to refer to everyday life for contextualization? In media and communication studies, interest in everyday life has a long history. The idea of everyday life has been central to approaches and research interests in cultural studies (Gray, 2002; Morley, 1992), media phenomenology (Pink & Leder Mackley, 2013; Scannell, 1995) or media ethnography (Hermes, 1995; Radway, 1984). The term has been particularly central to theories of domestication (Haddon, 2016; Silverstone et al., 2021) focused on processes of gradually integrating media technologies in the home. Roger Silverstone wrote a classic volume on Television and everyday life (Silverstone, 1994), arguing that in order to move past debates on television as ‘good’ or ‘bad’ and actually understand what it is, we have to consider television as embedded in tensions and dynamics of everyday life. Shaun Moores (2000) applied everyday life as a framework for understanding the historical development of broadcast media, and Maria Bakardjieva (2005) analyzed the domestication of computers and internet technologies in everyday life. Elizabeth Bird (2003) wrote The Audience in Everyday Life to argue for the relevance of ethnographic methods to understand our media-saturated reality, while Tim Markham (2017) wrote an introductory textbook titled Media and Everyday Life to present topics and thinkers in media studies through their relevance to daily life. All of the above are books on media with ‘everyday life’ in the title. Moreover, the term keeps popping up in journal articles on a variety of topics regarding media use: A comparative study of why people read print newspapers in the digital age refer to how different media are integrated into everyday life (Boczkowski et al., 2021), while a study of people who prefer online media at home find that digital alternatives are perceived to be better integrated into domestic everyday life (Müller, 2020). In analysis of how and why we follow news, the idea of the everyday provides a way of situating ordinary users at the centre of attention, by discussing everyday news use (Groot Kormelink & Costera Meijer, 2019) or everyday public connection (Swart et al., 2017). In debates about datafication and emergent technologies, the notion of the everyday is used to highlight human and social experiences with for instance self-tracking (Lomborg & Frandsen, 2016), smart homes (Hine, 2020) or algorithmic media (Willson, 2017). What do these different contributions have in common? They refer to everyday life to signal a position, because referencing ‘everyday life’ holds some empirical, methodological or theoretical implications. The term can be invoked to answer the ‘so what’-question: A compelling reason for why we need to study media at all is its relevance to everyday life (Silverstone, 1999). Today we can adapt this argument to why we need to study the smartphone – it is part of everyday life. Through such statements, we frame the smartphone as a technology and research topic that is recognizable and relevant to experiences and dilemmas each of us encounter. The smartphone has transformed society, but it has done so through our everyday interactions. Similarly: Why does it matter if people read international news or look at cat videos online, watch Netflix or Linear TV, listen to music on Spotify or prefer vinyl records? If you are interested in media business models or media policies, and find the choices users make a bit puzzling, you might need to look into motivations and contexts in everyday life to gain a deeper understanding of what goes on. Attention to everyday contexts can both complicate and enhance insights gained from other types of tracking and measurements of media use (Groot Kormelink & Costera Meijer, 2020). To understand new technologies, or connect critiques of these phenomena to people’s experiences, everyday life is an essential framework: It is easier to grasp the idea of ‘the Internet of Things’ (Bunz & Meikle, 2018) as having to do with whether your refrigerator needs internet connection, than through concepts such as machine learning or smart sensors. Sometimes the position signalled by referring to everyday life is explicitly normative. A key example is the debate on everyday experiences with datafication, or ‘the quantification of human life through digital information, very often for economic value’ (Mejias & Couldry, 2019). The idea of so-called ‘big data’ as more precise or valuable has been met with critical questions (Boyd & Crawford, 2012), and with concern for how audience engagement can be harvested and utilized for opaque purposes (Ytre-Arne & Das, 2020). In criticizing these developments, the notion of ‘everyday life’ is central to put the human experience of living in datafied conditions front and centre (Kennedy & Hill, 2018), or to focus on the people rather than systems (Livingstone, 2019). This interest further corresponds to feminist (D’Ignazio & Klein, 2020) and postcolonial critiques (Milan & Treré, 2019) of datafication and power. We can also signal analytical and methodological interests by referring to everyday life: The term is used to prioritize context over generalizability, and ordinary user perspectives and experiences over media professionals and institutions. This could imply attention to small acts of engagement in social media (Picone et al., 2019), and inclusion of seemingly mundane practices of media use (Hermes, 1995; Sandvik et al., 2016). An everyday life perspective is a backdrop for cross-media research (Lomborg & Mortensen, 2017; Schrøder, 2011) rather than pre-selecting which media to study based on the researchers’ preconceived notions of what matters. Qualitative researchers and ethnographers also draw on ‘everyday life’ as a term that points towards preferred methods: Talking to people about a day in the life (del Rio Carral, 2014), ‘capturing life as it is narrated’ (Kaun, 2010) with diary methods, and exploring experiences and reflections in informants’ own words. Some quantitative studies of media use also use the term (Hovden & Rosenlund, 2021) and research on everyday media repertoires can combine qualitative and quantitative approaches (Hasebrink & Hepp, 2017). I am also someone who often explain and position my key research interests through the notion of everyday life. A long-running interest in everyday life has informed my preference for qualitative and user-focused methods, in the studies I draw on in this book and in other projects. I have used the term ‘everyday life’ in the title of publications (Moe & Ytre-Arne, 2021; Ytre-Arne, 2012), and also explored how media use changes with biographical disruption to everyday routines (Ytre-Arne, 2019) or discussed audience agency in everyday encounters with digital and datafied media (Ytre-Arne & Das, 2020; Ytre-Arne & Moe, 2021a). For me, the everyday signals a perspective on why and how to study media use: it is important because it is part of daily life, it is interesting because everyday life is diverse and meaningful, and it is impossible to be done with because it changes constantly. I do not think there is any necessary contradiction between an everyday perspective versus a societal or political perspective on media use – instead, everyday life is where political dimensions of media are experienced, interpreted, and acted upon. This point runs as an undercurrent through the analyses of this book and is highlighted in the concluding chapter. What is Everyday Life? We have established that media are part of everyday life, and that research on media use is interested in everyday life. That is not to say that definitions everyday life abound in the literature referenced above, or in the field at large. Even classic contributions observe that commenting on the topic of everyday life might seem simplistic (e.g. Silverstone, 1994, p. 19). There is considerable variation in how precisely or extensively the concept is explained: Some works develop distinct philosophical understandings (e.g. Bakardijeva in Sandvik et al., 2016), or ground the term in substantial discussion of different theoretical positions (e.g. Cavalcante et al., 2017). Some authors define the term and how it connects to methodological and analytical frameworks in their studies). Others explain adjacent concepts to the everyday, such as the study mentioned above of why people still read print newspapers (Boczkowski et al., 2021), which draws on theories of ritualization, sociality and cultural contexts. Nevertheless, everyday life is theorized in disciplines from human geography (Holloway & Hubbard, 2001) to psychology (Schraube & Højholt, 2016). Some central philosophical contributions are Henri Lefebvre’s Critique of Everyday Life (1947), which formulates a Marxist-inspired argument about the importance of this sphere of human conduct in the face of capitalism and technological change, and Michel De Certeau’s The Practice of Everyday Life (1984) which emphasizes the concept of potentially subversive tactics in people’s navigation through daily life. Another key work is The Structures of the Lifeworld (Schutz & Luckmann, 1973) which formulates Alfred Schutz’ theory of the lifeworld in which everyday life is enacted, including spatial, temporal and social dimensions, and how we move through ‘zones of operation’ where people and places beyond our immediate surroundings are yet within ‘restorable reach’ to us, through the familiarity or routines in the everyday which we take for granted (1973). This understanding has been particularly important to phenomenological and sociological studies of media and technologies in everyday life. Such philosophical works on everyday life are briefly to referenced in studies of everyday media use, a understanding that is more or less For (1984) to discuss the role of media in daily on and a growing as as philosophical interest in everyday life as a research that media are not used in from one or from personal an example of the of media use in dynamics at that media are an part of the way the everyday is p. and points that have been up in discussions of media (Hasebrink & Hepp, and of media use as mundane but yet meaningful in everyday (Hermes, 1995; Sandvik et al., 2016). In study of early internet use at Bakardjieva provides a theoretical discussion of how and Lefebvre’s theories relate to communication technologies, the idea of a critical phenomenology to understand users as as Roger work on everyday life also Schutz’ understanding of the and further of the in a discussion of whether this lifeworld is different in conditions of (Silverstone, Silverstone debates about order and in a world of societal and new communication with an that television is we have seemingly to take for as a technology and social and as part of our everyday lives. these Silverstone emphasizes the of routines and familiarity in in the of the world at and a sense of these are the of social order and everyday life. the and for as as through the and our lives take and within those and and we to go about our or for the most the and the that to our and (Silverstone, 1994, p. In this everyday and a sense of a concept to describe of and in people’s experience of the world and sense of central to how people position in the world and to life is also a key concept in more recent theory of digital communication as when we through digital media, and in have our continued in the world 2021). discussion how of or through digital media can to the of the these theories of everyday life, some key dimensions Everyday life has to do with the of space and people and through which we make and relate to the and our position in it I draw on these dimensions to further situate media use in everyday life, how we use media for navigation across social Media Use in Everyday Life To understand media use – applied as an term for all kinds of relationships and with media and communication technologies – we need to situate media use as part of everyday life, in people’s lifeworlds. on the ideas above, of familiarity and and of spatial, social and dimensions, we can different and positions for media. I am particularly interested in how we use media to orient ourselves as we move through our everyday lives, as part of what I navigation across social What does this Everyday media use is because we do not it from – we rely on that we are regarding media use as as other aspects of everyday up in the and not you have done before – instead of the same of and the same on your smartphone. other and and media use practices are particularly essential to the of everyday life by Silverstone, Markham and are also a central concept in media and communication psychology and central to studies to grasp user over or across We everyday in and around – including media Everyday life multiple social domains – such as work and life – that are meaningful to us and that we with and that also important contexts for how we use media. There are research that of media use in different social for instance focused on life such as or experiences such as (e.g. Das, & 2020). between life such as a or a are so significant because the social domains of our everyday lives change with these events. These social domains are essential to the we find in life, the conduct of everyday life an We with social domains in – including media use and A interest I in this book is how we use media across and social for what I refer to as Everyday media use navigation across multiple social domains because an ordinary day can an of and in which we different social with different people. Everyday life can be and with to at or or but whether we have plans for or go with the some of and navigation is both and We conduct such navigation in – including media use and Digital technologies have become to this navigation – and but also and to We have established that media are part of daily and that such routines are essential to everyday life We can also discuss if and how the social domains of everyday life are or and how these processes (Couldry & Hepp, 2017; Hepp, 2020). But my main interest in this book is how our navigation across the social domains of everyday life changes with digital media – how we use digital media to connect to different social orient ourselves to what goes on and across contexts. Media use is essential to the navigation of everyday life, and the role of media in this navigation holds for how we experience our lives as meaningful, for how we understand and situate ourselves in the How we conduct this navigation is changing with the and datafication of the media, particularly after the smartphone. Media Use in Everyday Life The theories of everyday life that are most central to media and communication studies from an of and the domestic sphere is the social that has the most dynamics and the of the home are central to analyses from discussion of who the to what when the people television also have and computers & 2016). we can as Silverstone could in classic that is a domestic It is at home. at home. at (Silverstone, 1994, p. and mobile and social media a of the established when living and for a question in internet studies of whether and how people would actually to make space for computers in their homes is more not just by and but also by and technologies. The home is still but our navigation with media and beyond the home has A broader point is that the proliferation of digital media has it more difficult to make about how to situate media in everyday life, while media might be more important than to how we across our daily lives. This also has for the analytical concepts and approaches we to study everyday media To analyze media in everyday life, it is to a particular or media and look for its and in everyday to into how the cultural role of television in people’s everyday lives. But to for the for variation in everyday media use, it is more relevant to start with people and how we live our lives, and how media matters. of the scholarship discussed in this chapter for the of less approaches to media studies – media might need to be in order to understand what it I will particularly draw on approaches to situate media use in everyday life through a user Media repertoires and public Media repertoires is a concept to the totality and meaningful between media a (Hasebrink & & Hepp, 2017). the essential insight that are a key of approaches is to focus less on experiences with The of or using and instead how these or different are to each other in the context of a everyday media media approaches which media users have a how prioritize between different and how people and the totality of their media Media research has from how to of repertoires towards growing interest in repertoires as and how are and change over & Schrøder, et al., 2021; et al., Ytre-Arne, 2019). connection is a concept that people’s to society, in a sense – how people connect to public life, or (Couldry et al., et al., 2017; Ytre-Arne & Moe, The of a public connection – as to a focus on whether people follow news or – is to more what people are interested and how follow those across but also beyond (Couldry et al., & Ytre-Arne, 2021). Media is important to public connection, but not the only means of societal and public connection can take and define public connection as ‘the shared of that to and in and political in everyday life’ (Swart et al., and that relevance and engagement are dimensions in how media becomes meaningful in everyday life. of these perspectives imply that there is answer to or why media in everyday life – it is and perspectives are up to analysis of the that have to everyday media In this book, I draw on media approaches to analyze everyday media use from the perspective of and on the public connection concept to discuss how people connect to society through everyday media A More Digital Everyday Life A different way of situating media in everyday life is to if one the other, and if which way

Noninvasive evaluation of aortic stenosis severity utilizing Doppler ultrasound and electrical bioimpedance

BackgroundEarly diagnosis of mild cognitive impairment (MCI) is essential for timely treatment planning. With recent advances in the wearable technology, interest has increasingly shifted toward computer-aided self-diagnosis of MCI using wearable electroencephalography (EEG) devices in daily life. However, no study so far has investigated the optimal electrode configurations for the efficient diagnosis of MCI while considering the design factors of wearable EEG devices. In this study, we aimed to determine the optimal channel configurations of wearable EEG devices for the computer-aided diagnosis of MCI.MethodWe employed an EEG dataset collected from 21 patients with MCI and 21 healthy control subjects. After evaluating the classification accuracies for all possible electrode configurations for the two-, four-, six-, and eight-electrode conditions using a support vector machine, the optimal electrode configurations that provide the highest diagnostic accuracy were suggested for each electrode condition.ResultsThe highest classification accuracies of 74.04% ± 4.82, 82.43% ± 6.14, 86.28% ± 2.81, and 86.85% ± 4.97 were achieved for the optimal two-, four-, six-, and eight-electrode configurations, respectively, which demonstrated the possibility of precise machine-learning-based diagnosis of MCI with a limited number of EEG electrodes. Additionally, further simulations with the EEG dataset revealed that the optimal electrode configurations had significantly higher classification accuracies than commercial EEG devices with the same number of electrodes, which suggested the importance of electrode configuration optimization for wearable EEG devices based on clinical EEG datasets.ConclusionsThis study highlighted that the optimization of the electrode configuration, assuming the wearable EEG devices can potentially be utilized for daily life monitoring of MCI, is necessary to enhance the performance and portability.