Continuous Remote Monitoring Research Articles

Use of lightweight FFT-based algorithms for remote measurements using DIC

Abrupt collapse events that result in casualties due to failure of load-bearing structures have been reported in recent years. Continuous remote monitoring of these structures, assessing the behavior under operational load, could provide a reliable prevention, as the developing damage manifests itself through a loss of stiffness, and therefore excessive deflections. Digital image correlation (DIC) algorithms based on fast Fourier transform (FFT) were implemented in a small computer unit Raspberry Pi, capable of remote operation in a low-energy demand mode. The unit is fully autonomous, capable of localizing QR code targets and extracting encoded information. This strategy allows us to instantly evaluate displacements of QR codes attached to any surface and send the data to a server. The software was developed in Python, allowing for two modes: the online mode for current data evaluation with information transfer via the MQTT protocol and the offline mode used for retrospective evaluation.

Remote Estimation of Blood Pressure Using Millimeter-Wave Frequency-Modulated Continuous-Wave Radar.

This paper proposes to remotely estimate a human subject's blood pressure using a millimeter-wave radar system. High blood pressure is a critical health threat that can lead to diseases including heart attacks, strokes, kidney disease, and vision loss. The commonest method of measuring blood pressure is based on a cuff that is contact-based, non-continuous, and cumbersome to wear. Continuous remote monitoring of blood pressure can facilitate early detection and treatment of heart disease. This paper investigates the possibility of using millimeter-wave frequency-modulated continuous-wave radar to measure the heart blood pressure by means of pulse wave velocity (PWV). PWV is known to be highly correlated with blood pressure, which can be measured by pulse transit time. We measured PWV using a two-millimeter wave radar focused on the subject's chest and wrist. The measured time delay provided the PWV given the length from the chest to the wrist. In addition, we analyzed the measured radar signal from the wrist because the shape of the pulse wave purveyed information on blood pressure. We investigated the area under the curve (AUC) as a feature and found that AUC is strongly correlated with blood pressure. In the experiment, five human subjects were measured 50 times each after performing different activities intended to influence blood pressure. We used artificial neural networks to estimate systolic blood pressure (SBP) and diastolic blood pressure (SBP) with both PWV and AUC as inputs. The resulting root mean square errors of estimated blood pressure were 3.33 mmHg for SBP and 3.14 mmHg for DBP.

Mobile blood depots in ground ambulances in compliance with French legislation: A feasibility study.

Prehospital transfusion is a way of improving the management of hemorrhagic shock. In France, prehospital transfusion is struggling to develop, both because of logistical difficulties and particularly restrictive legislation. To comply with this, we propose to store the blood products (BPs) in ground ambulances with refrigerated boxes allowing remote continuous monitoring of storage conditions, called "NelumBox" (Tec4med Lifescience GmbH). To open them, the ambulance's team needs a code that is only given by the Transfusion Center if the request meets all required regulatory criteria. We conducted a prospective simulation-based feasibility study using dummy BPs. Two ambulances were equipped. Simulations were triggered unexpectedly, including during on-call hours. The ability to quickly access the BPs was the main judgment criterion. The quality of hemovigilance during these simulations was also examined. Twenty-two simulations were performed. The ambulance's team was able to access the BPs in 100% of cases. The average waiting time for receiving the unlocking code was 5 min 27 s (SD = 2 min 12 s, MAX = 12 min 00 s). The transfusion traceability was compliant with regulations in 100% of cases. The transfusion center was able to remotely monitor BPs storage conditions for the entire duration of their stockage in the NelumBox. The present procedure is efficient, repeatable, and fast. It guarantees a strict transfusion safety without slowdown a severe trauma management, while complying with French regulations.

Automated Sampling System for Monitoring 85Kr in Air

Radioactive krypton-85 (85Kr) gas, a chemically inert and non-proliferation indicator, is derived from fission products. Its detection relies on the Budesamt für Strahlenschutz–Institute of Atmospheric Radioactivity (BfS-IAR) method, which necessitated impurity removal using soda lime, silica gel, and liquid nitrogen for cryogenic adsorption. This manual process requires frequent replacements, posing challenges for its automation. To address this, we developed a prototype krypton sampling system as an interim research product for the fully automated remote monitoring of covert nuclear activity. The system incorporates a hollow fiber membrane for impurity removal, a computer-controlled multi-position valve for sampling, and an electric cooler for adsorption. The impurity removal modules demonstrated high efficiencies, removing H2O and CO2 at 99.8% and 97.8% rates, respectively. Further, the custom-made sampling system can process 16 samples in a single run without analyst intervention. We conducted experiments to verify the automatic krypton sampling capability. The activity concentration of 85Kr in ambient air was measured using the BfS-IAR processing and detection system. The system exhibited a recovery rate of ~7.8% for krypton in 1000 L air, demonstrating good continuous remote monitoring capability. This study promotes the development of an automated analysis system for the detection of 85Kr in ambient air.

P-280 Continuous in-situ monitoring of female hormone levels as a tool to improve the efficacy of assisted reproductive technology (ART) and in-vitro fertilization (IVF) treatment

Abstract Study question Is it possible to remotely monitor a patient’s hormone levels during an ART cycle using an unobtrusive and subcutaneously injectable biosensor for real-time monitoring? Summary answer It is possible for in-situ remote continuous monitoring implantable devices to successfully measure patient blood hormone levels over a clinically relevant concentration range. What is known already Worldwide 48.5 million couples suffer from infertility. In the UK, assisted reproductive treatments (ART) have increased by almost ten-fold in the last 20 years. Hormonal imbalances are the leading cause of female infertility and the success rate of ART tremendously depends on the accurate measurement of the levels of hormones, namely Luteinizing Hormone, Progesterone and Beta Estradiol. These hormone levels change and pulsate during each patient cycle, requiring women undergoing ART treatments to have a blood draw and endocrinology analysis every 2-3 days, making ART treatment highly invasive to a patient’s lifestyle and at a high cost. Study design, size, duration In order to determine the feasibility and potential of the study question, a minimally invasive biosensor to monitor ART hormone levels in real time was developed. The biosensor was tested in vitro for the range of 1 pg/ml to 1 µg/ml in three analytical replicates. The resulting sensitivity of testing was measured in order to evaluate real-work applications. Participants/materials, setting, methods A gold working electrode was utilized and activated using cyclic voltammetry. After activation, a self-assembled monolayer (Thiol-EDC-NHS), was formed on the gold surface, followed by the separate addition of anti-Progesterone4 and Beta-estradiol antibodies. After the addition of each layer, the Differential Pulse Voltammetry (DPV) of the gold electrode was measured. Based on the peak current, calibration curves were plotted and the sensitivity of the sensors was calculated. All electrochemical measurements were performed using CHI potentiostat. Main results and the role of chance This electrochemical hormone biosensor technology) is based on the detection of Progesterone4 and Beta-estradiol biosensor electrodes which can continuously detect hormone levels with a limit of detection (LOD) and limit of quantification (LOQ) of 2.01 and 6.72 pg/ml, respectively. Further to this, the biosensor covers the detection of a wide range of hormone concentrations in the blood from 1 pg/ml to 1 µg/ml. The sensor was also characterised by microscopy techniques such as scanning electron microscope (SEM) and Raman microscopy. Next, the biosensors will be validated in-vivo by conducting animal trials allowing for the main parameters of the biosensors to be optimized according to the in-vivo study. Limitations, reasons for caution This novel implantable biosensor technology requires more upcoming validation in animal models before then being tested clinically to order to assess its ability for widespread use. Wider implications of the findings The development and implementation of an unobtrusive remote and continuous monitoring implantable system for hormonal concentrations monitoring that are vital for success in an ART procedure could transform the entirety of the process as well as positively influence patient's access to care. Trial registration number NA

Wearable devices for remote monitoring of hospitalized patients with COVID-19 in Vietnam.

Patients with severe COVID-19 disease require monitoring with pulse oximetry as a minimal requirement. In many low- and middle- income countries, this has been challenging due to lack of staff and equipment. Wearable pulse oximeters potentially offer an attractive means to address this need, due to their low cost, battery operability and capacity for remote monitoring. Between July and October 2021, Ho Chi Minh City experienced its first major wave of SARS-CoV-2 infection, leading to an unprecedented demand for monitoring in hospitalized patients. We assess the feasibility of a continuous remote monitoring system for patients with COVID-19 under these circumstances as we implemented 2 different systems using wearable pulse oximeter devices in a stepwise manner across 4 departments.

Remote Respiratory and Cardiac Motion Patterns Separation with 4D Imaging Radars.

Radar-based noncontact physiological signals monitoring is meaningful for daily health monitoring, post-disaster rescue, and public security. This paper focuses on the theoretical and experimental study of noncontact respiratory and cardiac motion signals separation employing remote sensing by a four-dimensional (4D) imaging radar. To adaptively separate respiratory and cardiac motion patterns, we propose a variational mode separation (VMS) algorithm. VMS is established on optimizing a variational problem to separate different modes. It minimizes the energy overlap of the heartbeat and respiration signals as well as their harmonics with an equality constraint. Both simulation and real scene data results show that the proposed VMS algorithm is suitable for separating the weaker cardiac motion pattern from the strong respiratory motion pattern, restraining the influence of respiration harmonics on the heartbeat component. Also, the continuous remote monitoring of respiratory rate (RR) and heart rate (HR) by employing the proposed method in a real scene shows a strong consistency with the reference respiration belt and electrocardiogram (ECG). The root mean square error (RMSE) of RR and HR for the noncontact measurement are 0.13 breaths per minute (brpm) and 1.7 beats per minute (bpm), respectively.

PO-02-135 DOES LA SIZE PREDICT OUTCOMES IN AF AND SYSTOLIC HEART FAILURE?

Significant left atrial (LA) enlargement often accompanies heart failure with reduced ejection fraction (HFrEF) and may determine the success of AF ablation. However, the impact of LA size on long-term outcomes remains unclear. We aim to determine the relationship between LA size and AF recurrence in patients with normal LV function (NLV) and HFrEF following AF ablation. Consecutive patients undergoing index AF ablation across 11 centres were stratified according to baseline LVEF (<50% or >50%). The impact of baseline LA size on 12-month AF recurrence was determined utilising continuous remote rhythm monitoring to detect arrhythmia recurrence and quantify AF burden. 360 patients were included (NLV=237, HFrEF=123). The HFrEF group (mean LVEF 34.9±8.3%) were younger (62±10 vs 65 ± 9 years, p=0.020), with larger LA size (LAVI 54.6±16.5ml/m2 vs 45.4±14.1ml/m2, p<0.001). Despite differences in LA size, freedom from AF was similar in those with and without HF (56% vs 54% respectively, Log Rank p=0.621, figure 1a). Similarly, AF burden did not differ between groups (median burden HFrEF 0% (0-1.1); NLV 0 (0-2.5), p=0.195). An age-matched 1:1 comparison of NLV and HFrEF (N=246) demonstrated no impact of baseline LA size on arrhythmia recurrence (p=0.579), despite larger LA in those with HFrEF (LAVI 54.6±16.5 vs NLV 45.0±15.0, p=0.0002). LA enlargement did not predict arrhythmia recurrence (HR 1.400, 95% CI 0.952-2.057, p=0.086) regardless of HF status (figure 1b). At 12 months, LV function normalised in 80% (LVEF>50%) of those with HFrEF (ΔLVEF: +19±13%, p<0.001) with a significant reduction in LA size (54.6±16.5 to 44.7±14.6ml/m2, p<0.001), comparable in those with and without AF recurrence (p=0.819). Baseline LA enlargement did not influence AF recurrence in those with or without LV recovery (HR 1.622 95% CI 0.702-3.748, p=0.258). LA enlargement did not determine the outcome of AF ablation in those with and without HFrEF. LA size is less useful in guiding patient selection for AF ablation in HFrEF

Continuous remote monitoring of a motorway section using geophones

Pavement monitoring has been a widespread area of research. Monitoring pavements using embeddable sensors and a data acquisition system is an active research topic, with important questions about the selection of appropriate sensors and data acquisition systems, and interpretation of data. This work presents results of the instrumentation of a French motorway section, using geophones and temperature probes. The sensors are connected to a remote monitoring system which is compact, has a low power consumption, and real-time data processing capabilities. This system performs continuous monitoring, under a heavy motorway traffic and transmits the data wirelessly to a remote server. This work focuses on the treatment and analysis of the sensor signals. It indicates a good reliability of the system and embedded sensors, and presents different methods of interpretation of the data, to monitor pavement deflections, but also traffic composition and traffic loads, which could be used for pavement management, for detection of pavement damage and preventive maintenance.

Identifying Desired Features That Would Be Acceptable and Helpful in a Wrist-Worn Biosensor-Based Alcohol Intervention: Interview Study Among Adults Who Drink Heavily.

Alcohol misuse is highly prevalent in the United States and results in a huge financial and public health burden. Current alcohol reduction treatments are underused, and there is a critical need for innovation in the field. Transdermal alcohol biosensors measure alcohol use passively and continuously and may be helpful tools in alcohol interventions. To date, however, alcohol biosensors have not been widely used to directly intervene on alcohol use. There is a new wrist-worn biosensor that could be used to help people reduce their drinking, although it is unclear how best to incorporate such a device into an alcohol intervention. We aimed to identify desired features that would be acceptable and helpful in a wrist-worn biosensor-based alcohol intervention for adults who drink heavily. Participants were recruited through an alcohol contingency management study, a contact registry, and participant referral. To qualify, participants had to be aged at least 40 years, report drinking at least twice per week, and indicate interest in reducing their drinking. We conducted a semistructured interview with each participant via Zoom (Zoom Video Communications, Inc). The interview guide addressed general thoughts on the wrist-worn biosensor, how participants thought a wrist-worn biosensor could be used to help people quit or reduce drinking, types of information that participants would want to receive from the biosensor, how they would want to receive this information, and how they thought this information could be used to change their behavior. Interviews were transcribed verbatim and analyzed using thematic analysis. The sample comprised 20 adults (mean age 55.1, SD 6.1 years; 11/20, 55%, women; and 17/20, 85%, Black). Of the 20 participants, 9 (45%) had previous experience with the Secure Continuous Remote Alcohol Monitor continuous alcohol monitoring ankle biosensor from participating in an alcohol contingency management study. The desirable features could be grouped into 5 main themes: features that would influence willingness to use the biosensor (it should look attractive and be both comfortable to wear and accessible), personalized messaging (personalized biosensor-based prompts and feedback could be helpful), preference for time wearing the biosensor (for some, just wearing the biosensor could have an intervention effect), sharing data with others (this was appealing to many but not to all), and mental health support (many felt that mental health support could be incorporated into the biosensor). Five main themes that would maximize interest in using a wrist-worn biosensor for alcohol intervention were identified. Taken together, the identified themes could inform the development of a just-in-time adaptive intervention that uses a wrist-worn biosensor to help adults who drink heavily reduce their alcohol use.

A Wireless Infrared Thermometry Device for Postoperative Flap Monitoring: Proof of Concept in Patients.

Postoperative flap perfusion assessment methods still rely on the evaluation of traditional clinical indicators, which have the disadvantage of being subjective and burdensome. This study describes a self-designed infrared wireless thermometer for flap blood supply monitoring and evaluates its efficacy in the postoperative monitoring of 40 free flaps. The device consists of multiple temperature and humidity modules as well as a wireless module, which has the advantages of low cost and continuous remote monitoring. The alarm time of the wireless infrared thermometer was 30.5 ± 3.1hours, and the clinical observation reported 41.7 ± 13.6hours. In future studies, the device will be tested on different types of flaps in a porcine model.

Continuous Blood Pressure Monitoring Using Nonpulsatile Photoplethysmographic Components for Low-Frequency Vascular Unloading

<italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Objective</i> : Continuous blood pressure (BP) monitoring gives a better understanding of a person’s cardiovascular health status than single BP measurements. The existing measurement techniques are often highly complex and expensive, or suffer from inaccuracies. We propose a simple yet effective technique for continuous blood pressure monitoring. <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Methods</i> : Our method is based on the finding that the non-pulsatile (DC) component of the photoplethysmograph (PPG) correlates with blood pressure. By keeping the infrared PPG DC component constant by altering the applied external pressure using a feedback mechanism the BP can be measured continuously. This way the pressure read from the pressure sensor follows the mean intra-arterial BP. We call this low-frequency vascular unloading. We propose a method for assessing the measurement error introduced by changes in vasomotor tone. Green PPG was used for the vasomotor compensation method. We packaged the technology to a wearable finger-worn device similar to a pulse oximeter probe. <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Results</i> : We measured over 90 minutes of continuous BP data from total of 7 subjects. The subjects were asked to perform different BP altering maneuvers during the measurement. The ability to track BP changes was verified by continuous mean arterial pressure (MAP) readings measured with the reference device (CNSystems CNAP 500) and our device, resulting in correlation of <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">r</i> = 0.894 and (( <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">mean</i> ± <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">SD</i> ) mmHg) of (0.3±4.3) mmHg for mean arterial pressure. Without vasomotor tone compensation the results were with slightly less accurate: <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">r</i> = 0.83, (-1.4±5.1) mmHg. <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Conclusion</i> : The proposed technology performed well compared to traditional vascular unloading technique while requiring significantly less complex control logic and no fast-switching pneumatics. <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Significance</i> : The proposed technique is simple, yet effective, low-cost solution and it can be constructed from off-the-shelf components and miniaturized into a wearable form factor. The technique has potential in the field of health wearables and remote continuous BP monitoring for personalized health applications.

Remote Continuous Temperature Monitoring for Postoperative Complications: A Urinary Retention Case Report

Remote Continuous Temperature Monitoring for Postoperative Complications: A Urinary Retention Case Report

Development, research of a model and an algorithm for organizing data transfer in a monitoring device

The article examines the use of the graph theory method, in particular, the Petri net graph, for the development of microprocessor devices for remote continuous monitoring of the state of railway automation control equipment using Internet of Things technologies. Based on it, the model of the behavior of a set of modules that determines the state of automatic blocking signal point devices was studied.

Continuous remote monitoring in post-bariatric surgery patients: development of an early warning protocol.

Continuous monitoring of vital parameters after bariatric surgery can detect postoperative bleeding or anastomotic leakage. This report describes the development of a continuous remote early warning score (CREWS). This is an EWS-based notification protocol for deterioration detection in bariatric patients. Catharina Hospital, the Netherlands. Several CREWS protocols were developed by combining thresholds indicative of tachycardia and tachypnea using literature insights and expert sessions. These protocols were tested retrospectively using continuously measured vital signs in a cohort of 185 patients who underwent primary bariatric surgery. A wearable remote monitoring device (Healthdot, Philips) was used in hospital and at home up to 14 days after surgery. The outcomes included were demographics, use of beta-blockers, and complications necessitating reintervention. Thresholds of 110 beats per minute (bpm) and 20 breaths per minute (rpm) for heart rate andrespiration rate, respectively, detected postoperative bleeding and anastomotic leakage with 75% (3/4 patients) sensitivity. The protocol was silent (no alarms/day) in 69.5% of patients and produced more than 1 alarm/day in 1.6% of patients. The average postoperative heart rate was unaffected by the use of beta-blockers. A description of the steps in the development of an EWS protocol in bariatric patients based on continuous vital sign monitoring is useful. The most sensitive and silent protocol measured heart rate and respiratory rate with thresholds of 110 bpm and 20 rpm and appeared to be feasible for clinical use. There seemed to be no clinically relevant impact of beta-blockers. This CREWS protocol could be a starting point for future studies.

Prognostic significance of remotely monitored nocturnal heart rate in heart failure patients with reduced ejection fraction

Elevated resting heart rate is a risk factor for cardiovascular events. The purpose of this study was to investigate the clinical significance of nocturnal heart rate (nHR) and 24-hour mean heart rate (24h-HR) obtained by continuous remote monitoring (RM) of implantable devices. We analyzed daily-sampled trends of nHR, 24h-HR, and physical activity in patients on β-blocker therapy for chronic heart failure and with implantable cardioverter-defibrillators or cardiac resynchronization therapy defibrillators (CRT-Ds). Patients were grouped by average nHR and 24h-HR quartile during follow-up to estimate the respective incidence of nonarrhythmic death and device-treated ventricular tachycardia/fibrillation (VT/VF). The study cohort included 1330 patients (median age 69 years [interquartile range 61-77 years]; 41% [n = 550] with CRT-D; median follow-up 25 months [interquartile range 13-42 months]). Compared with patients in the lowest nHR quartile (≤57 beats/min) group, patients in the highest quartile group (>65 beats/min) had an increased risk of nonarrhythmic death (adjusted hazard ratio [AHR] 2.25; 95% confidence interval [CI] 1.13-4.50; P= .021) and VT/VF (AHR 1.98; 95% CI 1.40-2.79; P < .001) and were characterized by the lowest level of physical activity (P≤.0004 vs every other nHR quartiles). The highest 24h-HR quartile group (>75 beats/min) showed an increased risk of VT/VF (AHR 2.13; 95% CI 1.52-2.99; P< .001) and a weaker though significant association with nonarrhythmic mortality (AHR 1.80; 95% CI 1.00-3.22; P= .05) as compared with the lowest 24h-HR quartile group (≤65 beats/min). In remotely monitored patients with implantable cardioverter-defibrillator/CRT-D on β-blocker therapy for heart failure, elevated heart rates (nHR >65 beats/min and 24h-HR >75 beats/min) were associated with increased mortality and VT/VF risk. nHR showed a stronger association than 24h-HR with worst prognosis and lowest physical activity.

Digitally supported shared decision-making and treat-to-target in rheumatology: a qualitative study embedded in a multicenter randomized controlled trial

Patient-reported outcomes (PRO) represent a cornerstone in the management of patients with rheumatoid arthritis (RA). However, PRO are currently recorded mainly on paper and only during on-site appointments. Electronic PRO (ePRO) enable continuous remote monitoring and could improve shared decision-making (SDM) and implementation of a treat-to-target (T2T) approach. This study aims to investigate patient and physician experiences, perceived drawbacks and benefits of using an ePRO web-app (ABATON RA) to digitally support SDM and T2T. A qualitative study embedded in a multicenter randomized controlled trial (RCT) consisting of interviews with RA patients and physicians that were subsequently analyzed using deductive-inductive qualitative content analysis. Between August 2021 and May 2022, interviews with ten RA patients and five physicians were completed. Three key themes emerged in the analysis: (i) App user experiences; (ii) perceived drawbacks of app-supported rheumatology care; and (iii) perceived benefits of app-supported rheumatology care. Continuous ePRO collection and a high level of standardization strained some RA patients. Certain ePRO seemed outdated and were hard to understand. Patients and physicians appreciated having an improved overview of disease activity, capturing disease flares and continuous remote monitoring. Paper- and time-saving were associated with using ePRO. Physicians feared to become too focused on ePRO data, stressed the lack of ePRO monitoring reimbursement and app interoperability. For RA patients and physicians, benefits seemed to outweigh observed drawbacks of the digitally supported SDM using ePRO. The software was easy to use and could lead to a better understanding of the individual disease course, resource allocation and treatment of rheumatoid arthritis.

Wearable devices for remote monitoring of hospitalized patients with COVID-19 in Vietnam

Patients with severe COVID-19 disease require monitoring with pulse oximetry as a minimal requirement. In many low- and middle- income countries, this has been challenging due to lack of staff and equipment. Wearable pulse oximeters potentially offer an attractive means to address this need, due to their low cost, battery operability and capacity for remote monitoring. Between July and October 2021, Ho Chi Minh City experienced its first major wave of SARS-CoV-2 infection, leading to an unprecedented demand for monitoring in hospitalized patients. We assess the feasibility of a continuous remote monitoring system for patients with COVID-19 under these circumstances as we implemented 2 different systems using wearable pulse oximeter devices in a stepwise manner across 4 departments.

P.222 Wearable inertial sensors for longitudinal follow-up of patients with amyotrophic lateral sclerosis.

Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disease characterized by the loss of motor neuron leading to weakness and death often resulting from failure of the respiratory muscles. There have been numerous recent discoveries in ALS research leading to potential therapies that will need testing in clinical trials. Due to outcome measures limitations, trials, especially for neurodegenerative disorders, require large sample sizes, long durations and have a high risk for failure. Digital biomarkers collected with wearable devices could provide powerful outcome measures through an objective assessment performed in real-life. Remote continuous monitoring is an innovative method for quantifying disease progression in ALS patients providing for motor function assessment through patients' loss of ambulation. This opportunity for shorter and less burdensome clinical trials should be confirmed by further data collection. We designed a longitudinal natural history study in ALS. Participants were assessed with standard evaluations including the amyotrophic lateral sclerosis functional rating scale, six-minute walk test, Medical Research Council scores, Ashworth score, hand dynamometer, pulmonary function and cognitive tests every 3 months for 1 year. After each visit, patients were asked to wear for one month one inertial sensor at the ankle and one at the wrist for continuous assessment of motor function in real-life. These data will be compared with already acquired normative data. At the present time, 11 patients with ALS (3 females, 8 males) aged from 44 to 72 years old were included. Four patients discontinued the study due to death or permanent ventilation. Initial results suggest that upper and lower limb variables are lower in patient with ALS than in controls and show a downward trend over time. We will present longitudinal data along with correlation between change in traditional and digital outcome measures. We will show comparison between patients and controls.

E-Textile smart socks for gait analysis: a preliminary validation study

In the last years wearable technologies and smart fabrics are arousing a great deal of interest in the healthcare field. The possibility to directly interact with the body, along with the comfort of fabrics, represent great opportunities to develop interesting applications. Smart sensing socks, able to collect kinematic and/or foot pressure signals, are attractive solutions to perform gait analysis also outside clinical laboratories, e.g., in the home environment for remote continuous monitoring of patients. In this study we analyse the performance of Sensoria smart socks (Sensoria Health Inc. Seattle, WA, USA) in detecting the major spatio-temporal gait analysis metrics. We validate the results provided by the system in comparison with those of the IMU-based gait analysis system OPAL Mobility Lab by APDM (APDM Inc, Portland, OR, USA). Three textile pressure sensors are embedded in the Sensoria Sock to monitor plantar pressure, while the hardware unit is connected on the lateral part of the ankle to measure kinematic signals and transmit data to a smartphone. Twelve records were acquired on five healthy subjects (2 women). Each subject wore the sensing Sensoria smart socks and three OPAL Inertial Measurement Units (two on the feet and one in lumbar position), in order to perform simultaneous recording of the walking. The trial consisted of walking 10 metres, turning and returning to the starting point at preferred speed. The following resulting gait metrics were considered from the two systems and compared: Gait Cycle Time (GCT) [s], Stance Phase [%GCT], Cadence [steps/min]. Statistical comparison was performed by means of Bland-Altman test. Fig. 1 shows the results of the statistical analysis. Fig. 1 a presents the principal statistics of the considered metrics for the two systems. The table in Fig. 1 a also reports the numeric results of Bland- Altman test, expressed as the average bias (Sensoria minus OPAL) and its 95% Confidence Interval (CI) (Lower Bound LB – Upper Bound UB). Fig. 1 b, c and d respectively represent the Bland- Altman Plots for GCT, Stance Phase and Cadence. In this preliminary study we investigate the performances of the wearable Sensoria smart socks in evaluating the major temporal gait metrics. Results underline a general agreement in measuring GCT ( bias = − 0.00593 s ) and Cadence ( bias = − 0.0820 steps / min ). The confidence interval of bias includes the zero for both metrics, indicating that the differences randomly occur and are not systematic. The Bland-Altman plot for Stance Phase metric shows a significant difference between the measures provided by the two systems: Sensoria smart socks underestimate the foot stance phase duration with respect to the reference system OPAL Mobility Lab. In this case the average bias is − 7.75 % and its confidence interval does not include zero. The agreement in GCT values and the simultaneous disagreement of stance phase demonstrate discrepancies between the two systems in the detection of intermediate gait events (initial and terminal contact). In conclusion, smart socks performance in the detection of GCT and cadence are satisfactory, however improvements are needed in order to assess more specific gait metrics. In future studies, we aim to test the socks on a larger population and in the assessment of other temporal and spatial gait metrics.