Wearable Design Research Articles

A brief report: Lessons learned using wearable technology to collect data from adults receiving medications for opioid use disorder

ABSTRACT Background Incorporating wearable technology into substance use disorder research enables continuous, objective, and remote data collection, facilitating symptom monitoring to prevent relapse. However, implementation challenges may hinder data collection. This paper aims to assess adherence patterns to a wrist-worn wearable device, and to share lessons learned from incorporating wearable technology to collect physiological data from adults with opioid use disorder. Methods Employing a prospective observational design, we used convenience sampling to recruit adults receiving medications for opioid use disorder in outpatient settings. Wearable adherence was measured by days and nights worn over eight weeks, acceptability by a visual analog scale, and anecdotal notes tracked study activities and challenges. Results Twenty-three participants completed baseline, and 16 (70.0%) completed the study. Daytime and nighttime wearable adherence averaged 60.1% and 47.7%, respectively. Wearable adherence was highest at the earlier phase of the study (67.7%) and plateaued after overtime. User-related and technical challenges included digital illiteracy, protocol nonadherence, low motivation, measurement errors, and short battery life. Unique challenges included wearable design concerns and sleep problems. Conclusions This study demonstrates the feasibility of wearable use and highlights the potential to overcome challenges. Proactively sharing insights can facilitate wearable technology adoption for both participants and researchers.

Research on innovative design of intelligent wearable products based on human machine engineering and bionics

Designing intelligent wearable products entails integrating human factors, engineering, and bionics to develop ergonomic, efficient and convenient products. Human-machine engineering is a discipline that addresses the integration between the user wearing a particular system and improving the relationship between the user and the system. At the same time, bionics is an approach that aims to mimic biological systems and structures to enhance the performance of a particular product. This research explores the possibility of integrating these specializations to design new and enhanced wearable technology products with improved usability, convenience, and flexibility for practical usage. A detailed analysis of human biomechanics and ergonomic requirements established design parameters to ensure that wearable devices could be seamlessly integrated into daily life without hindering user movement. Bionic principles, such as the flexibility of animal joints and the energy-efficient movements of natural organisms, were applied to optimize the mechanical and structural aspects of the devices. This approach enabled the creation of products that mimic the natural dynamics of the human body, offering improved responsiveness and functionality. Prototypes were developed based on human-centred design principles and evaluated using simulation and testing environments. Wearables such as exoskeletons, bright clothing, and health-monitoring devices were examined for their ability to adapt to various physical conditions and environmental changes. Results demonstrate a significant increase in user comfort, reduction in mechanical strain, and enhanced performance, validating the effectiveness of integrating human-machine engineering and bionics in wearable design.

A wearable exhaled breath condensate (EBC) collector with controllable condensation microfluidics and a branched hydrophilic film

In previous research, exhaled breath condensate (EBC) analysis has emerged as a promising noninvasive method for assessing human health, potentially increasing patient testing acceptance. However, current EBC collection devices require cooling equipment for temperature reduction, leading to issues such as increased size, increased energy consumption, and a lack of real-time collection capability. In this study, an EBC collector was developed that integrates controllable condensation microfluidics with a biomimetic water-collecting film. Microfluids induce an endothermic reaction by rapidly dissolving water and NH4NO3 within the chamber, reducing the surface temperature to 3.5 °C. When positioned inside a mask, exhaled air undergoes condensation and collection on the branched biomimetic film. Human tests were conducted to analyze caffeine and nicotine in the collected EBC samples using LC–MS, demonstrating the device’s advantages in terms of power-free operation, wearable design, and rapid sample collection for metabolite detection.

MEMS and ECM Sensor Technologies for Cardiorespiratory Sound Monitoring-A Comprehensive Review.

This paper presents a comprehensive review of cardiorespiratory auscultation sensing devices (i.e., stethoscopes), which is useful for understanding the theoretical aspects and practical design notes. In this paper, we first introduce the acoustic properties of the heart and lungs, as well as a brief history of stethoscope evolution. Then, we discuss the basic concept of electret condenser microphones (ECMs) and a stethoscope based on them. Then, we discuss the microelectromechanical systems (MEMSs) technology, particularly focusing on piezoelectric transducer sensors. This paper comprehensively reviews sensing technologies for cardiorespiratory auscultation, emphasizing MEMS-based wearable designs in the past decade. To our knowledge, this is the first paper to summarize ECM and MEMS applications for heart and lung sound analysis.

Battery-free optoelectronic patch for photodynamic and light therapies in treating bacteria-infected wounds

Light therapy is an effective approach for the treatment of a variety of challenging dermatological conditions. In contrast to existing methods involving high doses and large areas of illumination, alternative strategies based on wearable designs that utilize a low light dose over an extended period provide a precise and convenient treatment. In this study, we present a battery-free, skin-integrated optoelectronic patch that incorporates a coil-powered circuit, an array of microscale violet and red light emitting diodes (LEDs), and polymer microneedles (MNs) loaded with 5-aminolevulinic acid (5-ALA). These polymer MNs, based on the biodegradable composite materials of polyvinyl alcohol (PVA) and hyaluronic acid (HA), serve as light waveguides for optical access and a medium for drug release into deeper skin layers. Unlike conventional clinical photomedical appliances with a rigid and fixed light source, this flexible design allows for a conformable light source that can be applied directly to the skin. In animal models with bacterial-infected wounds, the experimental group with the combination treatment of metronomic photodynamic and light therapies reduced 2.48 log10 CFU mL−1 in bactericidal level compared to the control group, indicating an effective anti-infective response. Furthermore, post-treatment analysis revealed the activation of proregenerative genes in monocyte and macrophage cell populations, suggesting enhanced tissue regeneration, neovascularization, and dermal recovery. Overall, this optoelectronic patch design broadens the scope for targeting deep skin lesions, and provides an alternative with the functionality of standard clinical light therapy methods.

Design and validation of dual-point time-differentiated photoplethysmogram (2PPG) wearable for cuffless blood pressure estimation

Background & objectivesMeasurement of blood pressure (BP) in ambulatory patients is crucial for at high-risk cardiovascular patients. A non-obtrusive, non-occluding device that continuously measures BP via photoplethysmography will enable long-term ambulatory assessment of BP. The aim of this study is to validate the metasense 2PPG cuffless wearable design for continuous BP estimation without ECG. MethodsA customized high-speed electronic optical sensor architecture with laterally spaced reflectance pulse oximetry was designed into a simple unobtrusive low-power wearable in the form of a watch. 78 volunteers with a mean age of 32.72 ± 7.4 years (21 to 64), 51% male, 49% female were recruited with ECG-2PPG signals acquired. The fiducial features of the 2PPG morphologies were then attributed to the estimator. A 9–1 K-fold cross-validation was applied in the ML. ResultsThe correlation for PTT-SBP was 0.971 and for PTT-DBP was 0.954. The mean absolute error was 3.167±1.636 mmHg for SBP and 6.4 ± 3.9 mm Hg for DBP. The ambulatory estimate for SBP and DBP for an individual over 3 days with 8-hour recordings was 0.70–0.81 for SBP and 0.42–0.51 for DBP with a ± 2.65 mmHg for SBP and ±2.02 mmHg for DBP. For SBP, 98% of metasense measurements were within 15 mm Hg and for DBP, 91% of metasense measurements were within 10 mmHg ConclusionsThe metasense device provides continuous, non-invasive BP estimations that are comparable to ambulatory BP meters. The portability and unobtrusiveness of this device, as well as the ability to continuously measure BP could one day enable long-term ambulatory BP measurement for precision cardiovascular therapeutic regimens.

Analyzing the Thermal Characteristics of Three Lining Materials for Plantar Orthotics.

The choice of materials for covering plantar orthoses or wearable insoles is often based on their hardness, breathability, and moisture absorption capacity, although more due to professional preference than clear scientific criteria. An analysis of the thermal response to the use of these materials would provide information about their behavior; hence, the objective of this study was to assess the temperature of three lining materials with different characteristics. The temperature of three materials for covering plantar orthoses was analyzed in a sample of 36 subjects (15 men and 21 women, aged 24.6 ± 8.2 years, mass 67.1 ± 13.6 kg, and height 1.7 ± 0.09 m). Temperature was measured before and after 3 h of use in clinical activities, using a polyethylene foam copolymer (PE), ethylene vinyl acetate (EVA), and PE-EVA copolymer foam insole with the use of a FLIR E60BX thermal camera. In the PE copolymer (material 1), temperature increases between 1.07 and 1.85 °C were found after activity, with these differences being statistically significant in all regions of interest (p < 0.001), except for the first toe (0.36 °C, p = 0.170). In the EVA foam (material 2) and the expansive foam of the PE-EVA copolymer (material 3), the temperatures were also significantly higher in all analyzed areas (p < 0.001), ranging between 1.49 and 2.73 °C for EVA and 0.58 and 2.16 °C for PE-EVA. The PE copolymer experienced lower overall overheating, and the area of the fifth metatarsal head underwent the greatest temperature increase, regardless of the material analyzed. PE foam lining materials, with lower density or an open-cell structure, would be preferred for controlling temperature rise in the lining/footbed interface and providing better thermal comfort for users. The area of the first toe was found to be the least overheated, while the fifth metatarsal head increased the most in temperature. This should be considered in the design of new wearables to avoid excessive temperatures due to the lining materials.

Multiscale Textile‐Based Haptic Interactions

Wearable haptic devices transmit information via touch receptors in the skin, yet devices located on parts of the body with high densities of receptors, such as fingertips and hands, impede interactions. Other locations that are well‐suited for wearables, such as the wrists and arms, suffer from lower perceptual sensitivity. The emergence of textile‐based wearable devices introduces new techniques of fabrication that can be leveraged to address these constraints and enable new modes of haptic interactions. This article formalizes the concept of “multiscale” interaction, an untapped paradigm for haptic wearables, enabling enhanced delivery of information via textile‐based haptic modules. In this approach, users choose the depth and detail of their haptic experiences by varying their interaction mode. Flexible prototyping methods enable multiscale haptic bands that provide both body‐scale interactions (on the forearm) and hand‐scale interactions (on the fingers and palm). A series of experiments assess participants’ ability to identify pressure states and spatial locations delivered by these bands across these interaction scales. A final experiment demonstrates the encoding of three‐bit information into prototypical multiscale interactions, showcasing the paradigm's efficacy. This research lays the groundwork for versatile haptic communication and wearable design, offering users the ability to select interaction modes for receiving information.

Intelligent perceptual textiles based on ionic-conductive and strong silk fibers

Endowing textiles with perceptual function, similar to human skin, is crucial for the development of next-generation smart wearables. To date, the creation of perceptual textiles capable of sensing potential dangers and accurately pinpointing finger touch remains elusive. In this study, we present the design and fabrication of intelligent perceptual textiles capable of electrically responding to external dangers and precisely detecting human touch, based on conductive silk fibroin-based ionic hydrogel (SIH) fibers. These fibers possess excellent fracture strength (55 MPa), extensibility (530%), stable and good conductivity (0.45 S·m–1) due to oriented structures and ionic incorporation. We fabricated SIH fiber-based protective textiles that can respond to fire, water, and sharp objects, protecting robots from potential injuries. Additionally, we designed perceptual textiles that can specifically pinpoint finger touch, serving as convenient human-machine interfaces. Our work sheds new light on the design of next-generation smart wearables and the reshaping of human-machine interfaces.

Automated ABR and MMN extraction using a customized headband for hearing screening

ObjectiveStimuli-elicited EEG responses, known as Event-Related Potentials (ERPs), reflect the health status of underlying electrophysiological processes and are frequently used for scanning sensory pathways. Current ERP extraction systems are expensive, complex, and bulky. This study aims to overcome these limitations by developing and validating a bimodal auditory ERP extractor headband. MethodsAn affordable, portable bimodal auditory ERP extractor was developed and validated for ABR (Auditory Brainstem Response) and MMN (Mismatch Negativity) response interpretation. Auditory stimuli were created using Presentation software. Adaptive filtering-based extraction was performed in EEGLAB (MATLAB) to derive the neural inferences. Extracted responses from n = 5 young adults were validated against CE-certified acquisition systems used in clinical practice. ResultsValidation results showed the grand average responses of ABR and MMN for n = 5 subjects matched. Furthermore, with and without stimuli ERP analysis showed significant differences for identified features (p = 0.00794 for ABR wave-V amplitudes, p = 1.22 * 10−5, and p = 2.62 * 10−5 for MMN peak latencies and area under the curves), ensuring that the response was due to the presented auditory stimuli. ConclusionThe results confirm the competency of the developed system to obtain MMN and ABR from young adults. A clear contrast between latency-amplitude scatter plots further ensures the competency of a developed system to acquire ABR and MMN. SignificanceThe novelty of the study is an easy-to-operate, affordable ERP extractor with adaptive filtering, wearable design, and configurable stimuli. This system can be a potential solution for large-scale hearing screening, providing detailed neural insights, including averaged responses and inter-trial variabilities.

Co-Designing Sensory Feedback for Wearables to Support Physical Activity through Body Sensations

Many technologies for promoting physical activity (PA) give limited importance to critical variables for engagement in PA, such as negative body perceptions. Here, we aim to address this gap by incorporating barriers and experienced body sensations into the design process for wearables and body-based devices thus expanding the design space for such technologies. We first report four co-design workshops with physically inactive participants (n=9); in these workshops, we explored tangible tools (i) to sensitize people to body sensations experienced when facing barriers to PA and (ii) to ideate how haptic and auditory feedback could transform body sensations to increase body-awareness and engagement in PA; results show several interactive sensorial patterns with potential to inform the design of body transformation wearables. These were validated through a follow-up workshop (n=13 participants) and reflections based on insights from a literature review. Our findings are significant for the design of ubiquitous technology to support and initiate PA in everyday contexts through a novel approach of transforming body perceptions/ sensations related to PA barriers. We contribute design inspirations and cards for identifying barriers to PA and to empower designers and researchers to integrate them early in the design process.

Mathematical Modeling and Statistical Analysis of Elederly Fall Detection System Using Improved Support Vector Machine

This research focuses on enhancing the safety of elderly individuals through early fall detection using mathematical modelling and statistical analysis of machine learning techniques for the application and effectiveness of elderly fall detection. Falls among the elderly can lead to severe consequences, necessitating timely intervention. Leveraging machine learning algorithms, this innovative open-source project analyses sensor data from wearable sensors like accelerometers, gyroscopes, and magnetometers, along with environmental data such as temperature and humidity, to promptly identify fall patterns. The project uses a dataset containing 14 variables, including age, sex, medical indicators, and more, collected from diverse subjects and activities. The results obtained during the testing phase underscore the importance of refining the model through dataset adjustments. As the physical, cognitive, and sensory functions decline with age, the risk of falls increases, highlighting the need for fall detection and prevention systems. This research reviews the latest machine learning-based systems for fall detection and prevention, analyzing them based on various parameters. It identifies support vector machines and wearable devices as common tools, but emphasizes the need for broader studies in different contexts. The paper also visualizes the performance metrics of ML algorithms in conjunction with various wearables and outlines future research directions, including energy efficiency, sensor fusion, context awareness, and wearable design, to advance fall detection and prevention for the elderly.

Wearable Loop Sensors for Knee Flexion Monitoring: Dynamic Measurements on Human Subjects.

Goals: We have recently introduced a new class of wearable loop sensors for joint flexion monitoring that overcomes limitations in the state-of-the-art. Our previous studies reported a proof-of-concept on a cylindrical phantom limb, under static scenarios and with a rigid sensor. In this work, we evaluate our sensors, for the first time, on human subjects, under dynamic scenarios, using a flexible textile-based prototype tethered to a network analyzer. An untethered version is also presented and validated on phantoms, aiming towards a fully wearable design. Methods: Three dynamic activities (walking, brisk walking, and full flexion/extension, all performed in place) are used to validate the tethered sensor on ten (10) adults. The untethered sensor is validated upon a cylindrical phantom that is bent manually at random speed. A calibration mechanism is developed to derive the sensor-measured angles. These angles are then compared to gold-standard angles simultaneously captured by a light detection and ranging (LiDAR) depth camera using root mean square error (RMSE) and Pearson's correlation coefficient as metrics. Results: We find excellent correlation (≥ 0.981) to gold-standard angles. The sensor achieves an RMSE of 4.463° ± 1.266° for walking, 5.541° ± 2.082° for brisk walking, 3.657° ± 1.815° for full flexion/extension activities, and 0.670° ± 0.366° for the phantom bending test. Conclusion: The tethered sensor achieves similar to slightly higher RMSE as compared to other wearable flexion sensors on human subjects, while the untethered version achieves excellent RMSE on the phantom model. Concurrently, our sensors are reliable over time and injury-safe, and do not obstruct natural movement. Our results set the ground for future improvements in angular resolution and for realizing fully wearable designs, while maintaining the abovementioned advantages over the state-of-the-art.

COMPUTATIONAL WEARABLES DESIGN: SHOE SOLE MODELING AND PROTOTYPING

Computational wearables design is based on the integration of algorithms into the design process. The use of computational design tools offers a series of advantages in the wearable product design modelling because a complete family of products can be produced with a limited effort from the designer, while at the same time geometries with high complexity can be dealt with a manageable way. The present paper aims to create the appropriate code for modelling shoe soles. The use of a visual programming language leads to a better understanding of the produced code and aims in controlling and optimising the output models. Following the proposed methodology, 3D scanning technologies and plantar pressure diagrams are used for introducing the sole customised geometry, and then the proposed algorithm creates a variety of alternatives of the final shoe sole geometry. As a result, both the customisation and the high number of alternative designs lead to increased creativity and customer satisfaction. Due to the complexity of the geometry produced, 3D printing technologies are incorporated for the prototype implementation.

Moving Matter: A methodology for material-led collaborations

Interdisciplinary movement artists and educators Rob Kitsos and Meagan Woods share the process behind Moving Matter: material-led collaborative choreographies, a research-creation project that offers a methodology for rethinking the dynamism between raw materials, garments, and the body. Moving Matter steers the locus of choreography and wearable design away from human hierarchy to instead support truer collaboration amongst all moving materials, both human and non-human. In a challenge to normative structures where costumery operates ‘in service’ of dance, the textile designs for Moving Matter do not support the complete autonomy and freedom of moving humans; the wearables have striking characteristics of their own that limit what the human body can do. In establishing parameters, we intend not to reverse the hegemony of human-led design to human-suppressed design, but to re-recognize the agency of all matter through material-led collaborations that support distributed power and collective, innovative approaches to making. This paper details the artists’ studio process and their methodology template for material-led collaborative process that can be adapted for practices within and beyond performance and art disciplines.

User-Centered Perspectives on the Design of Batteryless Wearables

Batteryless wearables use energy harvested from the environment, eliminating the burden of charging or replacing batteries. This makes them convenient and environmentally friendly. However, these benefits come at a price. Batteryless wearables operate intermittently (based on energy availability), which adds complexity to their design and introduces usability limitations not present in their battery-powered counterparts. In this paper, we conduct a scenario-based study with 400 wearable users to explore how users perceive the inherent trade-offs of batteryless wearable devices. Our results reveal users’ concerns, expectations, and preferences when transitioning from battery-powered to batteryless wearable use. We discuss how the findings of this study can inform the design of usable batteryless wearables.

Organic Electronics-Microfluidics/Lab on a Chip Integration in Analytical Applications.

Organic electronics (OE) technology has matured in displays and is advancing in solid-state lighting applications. Other promising and growing uses of this technology are in (bio)chemical sensing, imaging, in vitro cell monitoring, and other biomedical diagnostics that can benefit from low-cost, efficient small devices, including wearable designs that can be fabricated on glass or flexible plastic. OE devices such as organic LEDs, organic and hybrid perovskite-based photodetectors, and organic thin-film transistors, notably organic electrochemical transistors, are utilized in such sensing and (bio)medical applications. The integration of compact and sensitive OE devices with microfluidic channels and lab-on-a-chip (LOC) structures is very promising. This survey focuses on studies that utilize this integration for a variety of OE tools. It is not intended to encompass all studies in the area, but to present examples of the advances and the potential of such OE technology, with a focus on microfluidics/LOC integration for efficient wide-ranging sensing and biomedical applications.

A Comparative Analysis of Design Principles for Integration in Wearable Persuasive Multimedia

Many studies, to varying degrees, have confirmed the importance of persuasive approaches in wearable technology. Meanwhile, there are also a growing number of studies in persuasive multimedia, particularly in promoting awareness. Also, many studies reported on wearable multimedia, especially in game-based and VR/AR applications. Given the increasing emergence of these technologies, there is a need to integrate existing diverse research endeavours and consolidate them for improved planned effects on human attitude and behaviour, including one's awareness. However, a similar attempt to incorporate a triad of persuasive, multimedia and wearable design principles toward improved controllability awareness lacks empirical evidence. Here, this study explores the design principles of persuasive, multimedia and wearable technologies that can be leveraged into an integrated design model, especially in promoting controllability awareness of mental health issues. Moreover, this study believes exploring the potential integration of the design principles would significantly impact the application's effectiveness. Therefore, this study conducted a comparative analysis which involved 20 relevant studies pertinent to wearable design principles, persuasive design principles, and multimedia design principles. Furthermore, all identified studies were reviewed regarding the domain, the technology used, target outcomes, and utilisation of the design principles. As a result, this study discovered that many studies were on integrating persuasive and multimedia design principles and persuasive and wearable technologies. Therefore, the outcome of this study could be leveraged to incorporate all three design principles (i.e., wearable, persuasive technology, multimedia) into a conceptual model. The conceptual model is expected to produce a more effective result, especially in enhancing controllability awareness in the mental health domain.

Body map image coding to support wearable design for skin-to-skin contact

People place tools on their bodies during daily activities that impact their health and safety. Mapping the locations of this equipment and evaluating the appropriateness of these locations can aid people to achieve their goals. This paper considers the location of equipment, life support systems such as ventilation tubing and intravenous lines, on the human body during kangaroo care in hospitals. Kangaroo care (KC) is skin-to-skin contact between infants and adult caregivers, which dramatically improves health outcomes for both. This research provides information useful for design to support safe KC in the Neonatal Intensive Care Unit (NICU). Assessment of 100 images from a Google Image search conducted on May 19, 2021, using the search text ‘NICU kangaroo care tubes’ was undertaken. An expert NICU nurse verified that tube location followed best practices. This method documents human-body-tool interaction for improved safety and functioning across contexts.

Wearable gaming technology: A study on the relationships between wearable features and gameful experiences

With the parallel advancement and evolution of psycho-physiological sensors, haptics, and overall wearable computing, wearable devices have become a mainstay in everyday life. While gaming is one of the most intuitively appealing areas for using wearable devices, most gaming concepts relying on wearable devices have had only moderate success. Therefore, further knowledge is needed by game developers for innovating new gaming concepts, by wearable designers to innovate new affordances for gaming in wearables, and by gamers for seeing the possibilities of what wearables can bring to gaming. To address this research problem, we combined vignette and survey studies (N = 289) to investigate which features of wearables (integrability, wearability, modularity, sociability, programmability, bio-adaptability, audiovisuality, and embodied modality) would lead to gameful experiences. Overall, the results indicate that integrability to games, wearability, modularity, and sociability were dimensions of wearables which were most strongly connected with the expectation of a heightened game experience. The findings of the study contribute to the current understanding of the experiential value of gaming wearables, as well as providing practical guidance for gaming wearables designers and marketers.