Portable Monitoring Research Articles

Portable two-filter dual-flow-loop <sup>222</sup>Rn detector: stand-alone monitor and calibration transfer device

Abstract. Little overlap exists in the required capabilities of 222Rn (radon) monitors for public health and atmospheric research. The former requires robust, compact, easily transportable instruments to characterise daily to yearly variability >100 Bq m−3, whereas the latter requires static instruments capable of characterising sub-hourly variability between 0.1 and 100 Bq m−3. Consequently, detector development has evolved independently for the two research communities, and while many radon measurements are being made world-wide, the full potential of this measurement network can't be realised because not all results are comparable. Development of a monitor that satisfies the primary needs of both measurement communities, including a calibration traceable to the International System of Units (SI), would constitute an important step toward (i) increasing the availability of radon measurements to both research communities, and (ii) providing a means to harmonize and compare radon measurements across the existing eclectic global network of radon detectors. To this end, we describe a prototype detector built by the Australian Nuclear Science and Technology Organisation (ANSTO), in collaboration with the EMPIR 19ENV01 traceRadon Project and Physikalisch-Technische Bundesanstalt (PTB). This two-filter dual-flow-loop radon monitor can be transported in a standard vehicle, fits in a 19′′ instrument rack, has a 30 min temporal resolution, and a detection limit of ∼0.14 Bq m−3. It is capable of continuous, long-term, low-maintenance, low-power, indoor or outdoor monitoring with a high sensitivity and an uncertainty of ∼15 % at 1 Bq m−3. Furthermore, we demonstrate the successful transfer of an SI traceable calibration from this portable monitor to a 1500 L two-filter radon monitor under field conditions.

Portable Respiration Monitoring System with an Embroidered Capacitive Facemask Sensor.

Respiration monitoring is a very important indicator of health status. It can be used as a marker in the recognition of a variety of diseases, such as sleep apnea, asthma or cardiac arrest. The purpose of the present study is to overcome limitations of the current state of the art in the field of respiration monitoring systems. Our goal was the development of a lightweight handheld device with portable operation and low power consumption. The proposed approach includes a textile capacitive sensor with interdigitated electrodes embroidered into the facemask, integrated with readout electronics. Readout electronics is based on the direct interface of the capacitive sensor and a microcontroller through just one analog and one digital pin. The microcontroller board and sensor are powered by a smartphone or PC through a USB cable. The developed mobile application for the Android™ operating system offers reliable data acquisition and acts as a bridge for data transfer to the remote server. The embroidered sensor was initially tested in a humidity-controlled chamber connected to a commercial impedance analyzer. Finally, in situ testing with 10 volunteering subjects confirmed stable operation with reliable respiration monitoring.

Sensing performance of temperature insensitive microring resonators with double-layer U-shaped waveguide

An temperature insensitive microring resonator with double-layer U-shaped waveguide for sensing applications is proposed and investigated theoretically. The unique structure of microring resonator with double-layer U-shaped waveguide not only limits the light field in the ring, but also releases the evanescent field from the waveguide through the coupling of the upper and lower layers, thus enhancing the interaction between light and matter and improving the sensing ability. Then, through correctly selecting the cross-sectional dimensions of the waveguide, the bending radius, the spacing between the upper and lower waveguides and the shape of overlapping area, it is designed to have very low temperature dependence in aqueous solution, so as to obtain sensing accuracy and stability. The simulation results show that the sensitivity is 496 nm/RIU ± 5 pm/K. Within the temperature change range of 3.2 K, it can be considered that the measurement result is irrelevant to the change in ambient temperature. Compared with the other ring resonators, this resonator does not need extra temperature compensation equipment, active temperature controller, polymer cladding, or even extra processing of the measured data to eliminate the effect of temperature. Thanks to its excellent performance in temperature insensitive and sensing performance, the device is suitable for refractive index measurement in a complex environment. It might have broad application prospects in portable real-time monitoring equipment, for example, analyzing health status from the change of sweat composition, or detecting the content of microorganisms and other harmful substances in drinking water.

A Comparison of Particulate Exposure Levels during Taxi, Bus, and Metro Commuting among Four Chinese Megacities.

Exposure to inhalable particulate matter pollution is a hazard to human health. Many studies have examined the in-transit particulate matter pollution across multiple travel modes. However, limited information is available on the comparison of in-transit exposure among cities that experience different climates and weather patterns. This study aimed to examine the variations in in-cabin particle concentrations during taxi, bus, and metro commutes among four megacities located in the inland and coastal areas of China. To this end, we employed a portable monitoring approach to measure in-transit particle concentrations and the corresponding transit conditions using spatiotemporal information. The results highlighted significant differences in in-cabin particle concentrations among the four cities, indicating that PM concentrations varied in an ascending order of, and the ratios of different-sized particle concentrations varied in a descending order of CS, SZ, GZ, and WH. Variations in in-cabin particle concentrations during bus and metro transits between cities were mainly positively associated with urban background particle concentrations. Unlike those in bus and metro transit, in-cabin PM concentrations in taxi transit were negatively associated with urban precipitation and wind speed. The variations in particle concentrations during the trip were significantly associated with passenger density, posture, the in-cabin location of investigators, and window condition, some of which showed interactive effects. Our findings suggest that improving the urban background environment is essential for reducing particulate pollution in public transport microenvironments. Moreover, optimizing the scheduling of buses and the distribution of bus stops might contribute to mitigating the in-cabin exposure levels in transit. With reference to our methods and insights, policymakers and other researchers may further explore in-transit exposure to particle pollution in different cities.

MO661: Elimination of Middle and Large Uraemic Toxins in Short Daily Home Haemodialysis with Low Dialysate Volume: A Randomized Crossover Clinical Trial

Abstract BACKGROUND AND AIMS Portable haemodialysis (HD) systems with a low dialysate flow rate in a short frequent schedule have become an attractive option for patients on home HD (HHD). Although these systems have been demonstrated to be effective for removing low weight molecular uraemic toxins, there are few data on their removal ability of higher molecular weight toxins. This study assessed the uraemic toxin removal ability of the portable Physidia S3 Monitor in a short, frequent, 5 days/week, low-dialysate flux HHD versus 3 days/week, in centre online haemodiafiltration (OL-HDF). METHOD In an open, randomized, cross-over, single-centre, controlled, prospective study, 40 adult chronic HD patients were treated by a 2.5-h low flux dialysate HD session or a 4-h post-dilution OL-HDF. All other dialysis parameters including dialyzer (polysulfone high-flux dialyzer NS 1.8, Toray®) were kept constant in both the study arms. The weekly reduction rate (RR) and the weekly eliminated mass into dialysate (EM) of urea, creatinine, phosphate, β2-microglobulin, kappa (κFLC) and lambda (λFLC) free light chains and albumin, were intra-individually compared for the two dialysis types with linear mixed models. RESULTS There were no significant differences in the RR for urea, phosphate, κFLC and albumin, whereas the weekly RRs for creatinine and β2-microglobulin were significantly higher with the Physidia S3 system than those obtained with OL-HDF (Table). Only the λFLC RR was significantly higher with OL-HDF. Similar results were observed when weekly EMs were compared (data not shown). CONCLUSION This study demonstrates that treating patients with low flow dialysate HHD in a short frequent schedule with Physidia S3 system, instead of 3 days/week, in-centre OL-HDF, significantly increases the weekly elimination of β2-microglobulin, enabling an adequate clearance of small and large uraemic toxins.

MO380: Bio-Conductivity Measurement for Electrical Impedance Tomography (EIT) in Chronic Kidney Disease—A Non-Invasive and Portable Monitoring Approach

Abstract BACKGROUND AND AIMS Chronic kidney disease (CKD) is an escalating global health concern, and non-invasive means for early CKD detection is eagerly awaited. Kidneys are water- and electrolytes-rich organs with good bio-conductivity. Kidney fibrosis and tubular atrophy are characteristic pathological changes in CKD [1], and is associated with restricted blood perfusion, fluid diffusion [2,3] and hence reduced bio-conductivity. Electrical impedance tomography (EIT) emerges as a non-invasive, ionizing radiation-free imaging technique measuring dielectric properties of the body parts [4]. This study investigated the relationship of EIT indices and renal function in patients with various stages of CKD. METHOD We prospectively recruited 98 patients with different stages of CKD (Stage 1, n = 16; Stage 2, n = 15; Stage 3, n = 20, Stage 4, n = 36 and Stage 5, n = 11). EIT measurements were performed at two frequencies (33.6 and 100 kHz) using a portable EIT device with an electrode belt consisting of 16 gel electrodes. EIT data was pre-processed and reconstructed as mean conductivity maps. Frequency differencing was then performed between conductivity maps at two frequencies. Kidney-related dielectric parameters were extracted around the kidney region located at lower one-third of the frequency differencing conductivity map. Conductivity changes between frequencies were then computed and further regressed with individual biometrics. Predicted eGFR values was then computed and compared with the standard eGFR scores to evaluate its effectiveness on classifying CDK stages. RESULTS The detected mean bio-conductivity changes were −3.9, −67.5, −133.5, −212.6 and −294.7 (a.u.) in patients with CKD Stage 1, 2, 3, 4 and 5, respectively (Fig. 1A). Patients with more advanced stages of CKD tend to show more reduction in bio-conductivity, and eGFR correlated positively with reduction in bio-conductivity (R2 = 0.37, P < 0.001) (Fig. 1B). EIT-predicted eGFR (eGFREIT) was further computed by the captured conductivity changes and individual biometrics (Fig. 2). eGFREIT showed significant correlation with eGFR measured by blood tests (R2 = 0.54, P < 0.001). CONCLUSION EIT showed good correlation with renal function changes in CKD patients, and thus holds promise to be developed into a non-invasive and portable device for early CKD detection in both clinical and community settings.

HALITOSIS ASSESSMENT IN PATIENTS WITH ORTHODONTIC APPLIANCE AND THEIR ASSOCIATION WITH BULLYING

Halitosis is the term used to define the unpleasant odor exhaled through exhaled air, which may be signaling a pathological, physiological or adaptive condition. Most individuals who present this alteration experience personal discomfort, social embarrassment and emotional anguish, which can cause serious disturbances of coexistence, especially in the school environment. The etiology of halitosis is multifactorial, but its main cause comes from the formation of volatile sulfur compounds (VSC) resulting from the proteolytic bacterial action on stagnant organic matter in the oral cavity. The use of orthodontic appliances may be an agent related to the development of this alteration, since it favors the accumulation of organic residues, epithelial desquamation, gingival inflammation, in addition to making local hygiene difficult. Therefore, the present study aims to evaluate the breath of patients with orthodontic appliances and also the possible presence of bullying related to such an event, in young adults aged between 18 and 24 years, students at Universidade Paulista de Brasília. Breath assessment was performed using an organoleptic test (gold standard), which is performed by the examiner’s sense of smell, and a Halimeter® portable monitor, and saliva assessment was performed using a sialometry test, in which the amount of saliva was evaluated. The possible relationship with bullying was assessed through a specific questionnaire. Of the twelve students included in the study, seven presented halitosis when evaluated through the organoleptic test, however, of these seven only two presented parameters compatible with halitosis, when evaluated by the Halimeter®. In relation to bullying, this study showed that it was present in the lives of many respondents, but not necessarily because of breath.

Effects of sacubitril-valsartan on central and obstructive apneas in heart failure patients with reduced ejection fraction

ObjectiveThis study aimed to evaluate the effect of sacubitril-valsartan (SV) on central apneas (CA) and obstructive apneas (OA) in patients with heart failure with reduced ejection fraction (HFrEF).MethodsIn patients with HFrEF, SV initiation was titrated to the highest tolerable dosage. Patients were evaluated with portable apnea monitoring, echocardiography, and cardiopulmonary exercise testing at baseline and 3 months later.ResultsOf a total of 18 patients, 9 (50%) had OA, 7 (39%) had CA, and 2 (11%) had normal breathing. SV therapy was related to a reduction in NT-pro BNP and an improvement in LV function after 3 months. Portable apnea monitoring revealed a significant decrease of the respiratory event index (REI) after treatment with SV (20 ± 23 events/h to 7 ± 7 events/h, p = 0.003). When subgrouping according to type of apneas, REI, and time spent below 90% saturation (T90) decreased in patients with CA and OA (all p < 0.05).ConclusionIn this prospective study, SV treatment for 3 months in patients with CA and OA is associated with a significant decrease in REI.

A comparative study of heart rate variability and physical fitness in women with moderate and severe fibromyalgia

The aim of this study was to compare the physical fitness and cardiac autonomic activity among women with moderate and severe fibromyalgia (FM) and healthy women. This study included 35 women with FM (age: 46.2±8.9 years) and 17 healthy women (age: 44.3±9.9 years). Participants with FM were divided into moderate FM (n=15) and severe FM (n=20) according to the total score obtained in FM impact questionnaire. The heart rate variability was monitored using a portable cardiac monitor with participants resting in supine position during 10 min. Thereafter, the participants performed the chair sit and reach test, the chair stand test, and the 6-min walk test to measure the lower-body flexibility, lower-body muscle strength, and cardiorespiratory fitness, respectively. The lower-body muscle strength and cardiorespiratory fitness were both reduced in moderate and severe FM compared to healthy women (P<0.01), with greater reduction in severe FM when compared to moderate FM (P<0.05). In addition, the parasympathetic indexes of heart rate variability were all similarly decreased in both moderate and severe FM, when compared to healthy women (P<0.05). The cardiac parasympathetic activity is similarly decreased in women with both moderate and severe FM in comparison to healthy women, despite a greater physical deconditioning in severe FM.

A Portable Posture Monitoring Device for Gymgoers

With unprecedented witness in physical exercises, gyms are high in demand with their infrastructure and best exercise equipment to provide proper fitness to its customers. But incorrect posture is one of the overlooked issues that result in acute or chronic injuries while doing improper exercises. Heavy loads and wrong postures during the exercise are not monitored mostly due to insufficient assessment tools or infrastructure. The gait analysis setup makes it impossible to monitor exercise routines in regular gyms due to the space and expenditure. In this study, a wearable device integrated with multiple accelerometers is designed to monitor posture. This portable device can also deliver proper data for routines like squats, bench press, and deadlifts. Using built-in Bluetooth and Wi-Fi, the data can be tracked in real time. The real-time posture data can provide reliable information to the gym coaches for immediate correction remedy.

Factors Associated With Undiagnosed Obstructive Sleep Apnea in Overweight and Obese High-Tech Employees: A Multisite Cross-Sectional Study.

Background: Being overweight or obese is regarded as crucial risk factors for obstructive sleep apnea (OSA). Objectives: This study aimed to determine the influencing factors of overweight and obese employees with OSA in high-tech workplaces. Methods: A cross-sectional study design was employed. A total of 491 overweight and obese participants were recruited from a large-scale electronics industry. The Chinese version of Pittsburgh Sleep Quality Index, the Epworth Sleep Scale, and a portable sleep monitoring device were used for data collection. Logistic regression analysis was conducted to identify the factors affecting overweight and obese employees with OSA. This study was conducted from August 2019 to July 2020. Results: 60.5% of the overweight and obese participants were found to have OSA, of which 58.9% had mild and 18.5% had severe OSA, respectively. The results showed that age, neck circumference, snoring, and habitual drinking were the crucial factors affecting OSA. Remarkably, age and snoring times showed a significant correlation in predicting OSA of different severities. Neck circumference was an independent risk factor for moderate and severe OSA. Conclusion: More than 60% of the overweight and obese high-tech workplace employees were found to have OSA. We found that the older the age, the larger the neck circumference, a higher number of snoring instances, and drinking were important risk factors for predicting OSA in overweight high-tech employees. The healthcare providers should actively educate OSA-related information for employees in the workplace, and promote high-risk OSA groups to adopt screening based on at-home sleep apparatus.

Scoring heart rate increases as a surrogate arousal marker on portable monitor studies for obstructive sleep apnea: Impact on diagnostic accuracy and clinical decision‐making

Cortical arousal-related hypopneas are not scored on type 3 home devices, which therefore limits their diagnostic accuracy for obstructive sleep apnea. The objective of this study was to evaluate whether scoring heart rate accelerations as surrogate markers of arousal improves type 3 portable monitor diagnostic agreement compared with polysomnography and improves therapeutic decision-making. We prospectively recruited patients evaluated for obstructive sleep apnea to undergo in-laboratory simultaneous full polysomnography + type 3 portable monitoring. Hypopnea events were scored on portable monitor studies with and without autonomic scoring, which was defined as an associated increase in pulse oximetry-derived heart rate ≥6beats per min (autonomic hypopnea). Portable monitor diagnostic agreement compared with polysomnography with and without autonomic hypopnea scoring was assessed. We also evaluated whether reporting autonomic hypopnea scoring improves portable monitor clinical treatment decision agreement after four physicians reviewed clinical data and sleep study results (polysomnography, portable monitor with autonomic hypopnea, portable monitor without autonomic hypopnea). Eighty-two participants completed simultaneous polysomnography and in-laboratory portable monitor studies. Scoring autonomic hypopnea resulted in a decreased mean difference between in-laboratory portable monitor respiratory event index and polysomnography apnea-hypopnea index in Bland-Altman analysis (mean difference 14.6 per hr without versus 6.1 per hr with autonomic hypopnea scoring [p ˂ 0.01]), and increased intraclass correlation from 0.769 to 0.844. Inclusion of autonomic hypopnea scoring resulted in better accuracy between portable monitor and polysomnography expert's treatment decisions, and ultimately resulted in 24% fewer additional polysomnographies requested. The addition of pulse oximetry heart rate increases for autonomic hypopnea scoring during portable monitor resulted in better diagnostic agreement, improved clinical decision-making and reduced additional polysomnography testing.

Design and evaluation of an autonomic nerve monitoring system based on skin sympathetic nerve activity

The autonomic nervous system is closely related to cardiovascular diseases (CVDs). Simultaneous non-invasive recording of skin sympathetic nerve activity (SKNA) and electrocardiogram (ECG) is a new method for autonomic nervous system real-time assessment. This study presented a portable monitoring system based on SKNA. A system-level modification by combining a commercial analog front end (AFE) chip with a low-noise first-stage amplifier was implemented to reduce the system noise floor without a high-cost customized chip. An adaptive power-line-interference (PLI) filter and outliers clipping were developed to reject the PLI and motion artifacts in the signal. The laboratory experiment and clinical experiment were conducted to verify the performance and effectiveness of the proposed system. The laboratory results show that the proposed AFE has a much lower noise floor with 0.1 μVrms than the reference systems (PowerLab system). Moreover, the correlation coefficient of the envelope of SKNA (eSKNA) is 0.83, and the correlation coefficient of the heart rate variability (HRV) index is 0.99, suggesting a good performance in signal recording. The clinical results show that the proposed system can reflect sympathetic nerve activity significantly before and after anesthesia injection (p < 0.01), indicating its better feasibility in this application scenario than HRV-based devices (p = 0.40). The system achieves a comparable performance to the reference system and satisfactory performance for the autonomic nervous system assessment in clinical application.

Development of a Portable Infrared-Type Noncontact Blood Pressure Measuring Device and Evaluation of Blood Pressure Elevation during Driving

Hypertension has been established as a major risk factor for cardiovascular morbidity and mortality. Therefore, prevention of hypertension is an urgent matter to maintain people’s health and avoid death, and out-of-office blood pressure measurement is said to be an integral part of the diagnosis and management of hypertension. Hypertension not only causes loss of productivity and economic loss but is also a major cause of road accidents. Therefore, it is important to develop an in-vehicle noncontact blood pressure measurement system for drivers. In addition to measurement accuracy, proper detection timing is also important, and there must be no difference between noncontact and contact detection times. In this study, we introduce an infrared cuffless and portable noncontact blood pressure monitoring system, its measurement principle, and performance evaluation. A total of 13 male adults participated in the experiment to evaluate the effect of time lag between the use of the infrared blood pressure monitoring system and the contact blood pressure monitoring system using a driving simulator. The changepoint method was applied to detect the first change point in the blood pressure time series data caused by the unexpected first appearance of the vehicle. The results showed that the detection time of the developed system was about 2.5 s shorter than that of the contact-type continuous blood pressure measurement system, with no significant difference.

Experimental verification of real-time gamma-ray energy spectrum and dose monitor

The purpose of this study is to develop a portable monitor that can measure the energy spectrum and dose of gamma-rays simultaneously in real time for the benefit of medical staff who must work in clinical radiation environments. For this purpose, we have developed a prototype monitor using a CsI (Tl) scintillator combined with a multi-pixel photon counter (MPPC). For real-time measurement, we employed an improved sequential Bayesian estimation (k-α method) to convert the measured pulse height spectrum into an energy spectrum. Then we confirmed that reconstruction of the energy spectrum and dose estimation could simultaneously be carried out in real time by the k-α method in a radiation field composed of mixed standard gamma-ray sources. In this study, we carried out measurements in a background gamma-ray field to confirm applicability of the prototype monitor to the weakest type of radiation field. In addition, we conducted measurements in front of a nuclear fuel storage room (∼2 μSv/h) in the authors’ laboratory to evaluate practicality of the monitor for measuring fields with a complex energy spectrum. As a result, it was found that the dose could be estimated in about 20 s after start of measurements even in the background field. For the energy spectrum, it was instantly reconstructed within 60 s in front of the fuel storage room. On the other hand, it could successfully be estimated within 10 min in the background gamma-ray field. Currently, the convergence of the energy spectrum is determined visually from time dependent change of the spectrum and dose. As a next step, we will attempt to develop a more quantitative procedure for determining the convergence.

Early diagnosis and pathogenesis monitoring of wheat powdery mildew caused by blumeria graminis using hyperspectral imaging

Powdery mildew caused by blumeria graminis is responsible for wheat yield losses in combination with a decline in quality. Hyperspectral imaging as a promising non-invasive sensor technique has potential for early diagnosis and pathogenesis monitoring of wheat powdery mildew, which is a practice that allows for precision crop protection. Hyperspectral images were first captured before inoculation as healthy samples and daily 2 to 5 days after inoculation (dai) as infected ones. Principal component analysis (PCA) was applied to observe the discrimination capability between samples at different infected stages, while a gray-level co-occurrence matrix (GLCM) was used to extract textural features from the first three principal component images. Then partial least squares discriminant analysis (PLS-DA) model was developed to evaluate the ability for early diagnosis of the disease using effective wavelengths, texture features and their fusion, respectively. Compared with the models using spectral or textural feature alone, PLS-DA model using the fused dataset obtained the best performances with classification accuracy of 91.4 % in validation sets. Furthermore, spectral angle mapping (SAM) was performed to identify the infected tissue in wheat leaves 2 dai, and to monitor the pathogenesis of powdery mildew over time. The results from this study could be used to develop a portable field monitoring sensor for wheat powdery mildew.

Correlations between oxygen saturation parameters and obstructive sleep apnea severity in unattended portable monitoring

article: Correlations between oxygen saturation parameters and obstructive sleep apnea severity in unattended portable monitoring - Otorhinolaryngology 2022 March;72(1):21-5 - Minerva Medica - Journals

Investigation of the Vertical Profile Radio Refractivity Gradient and Effective Earth Radius Factor (k-factor) in Transmission Link Over Oyo, Oyo State, South Western Nigeria

Surface radio refractive gradient and k-factor are very imperative in observing propagation conditions, designing and planning of microwave communication links in the lower part of the atmospheric boundary layer. The measurement of weather variables (air temperature, atmospheric pressure, relative humidity and wind speed) were conducted in this study at the School of Science, Emmanuel Alayande College of Education, Oyo (7.83°N, 3.95°E), Oyo State, Nigeria. The research was carried out for a period of one year (January to December, 2020) using self-designed cost effective portable weather monitoring systems. The systems were sited from the ground to a height of 200 m on a 220 m Nigeria Television Authority (NTA) UHF channel 37 tower at Oke-Apitipiti in Oyo Town of Oyo State. The calculated daily and monthly averages data are employed to investigate the vertical surface radio refractivity and its refractivity gradient. The highest value of -1.093E+26 N-units/km was recorded in January, while the month of July experienced the least of about -9.305E+19 N-units/km. The months of January–July verified sub-refractive conditions with propagation conditions having varying degree of occurrence. On the other hand, super-refraction and ducting were recorded mostly between August–December from the study. The results also find applicability in radio engineering for refining VHF/UHF terrestrial links based on clear-air considerations which will support operational planning of terrestrial radio networks in Oyo, South Western Nigeria&#x0D; Keywords: Microwave; k-factor; refractivity gradient; sub-refractive; super-refraction

Portable Monitoring Device for Motor Rehabilitation Equipment with Rotor Shaft

A novel and portable device is proposed to monitor motor rehabilitation equipment, which can be mounted on most equipment with rotor shaft. The software of the device, whose main functions include equipment configuration, monitoring and statistical computation, is developed based on available sensor. The data collected by the device serve both department managers to learn the efficiency of the equipment, and physicians and therapists to understand the physical conditions of the patients who perform training exercises with the monitored rehabilitation equipment. About 2000 hours' monitoring has been carried out, and the experimental result indicates that the monitoring device is applicable to many types of motor rehabilitation equipment and achieves good monitoring accuracy. The data aggregated by the device can be used to evaluate the motor functions of the patients and make rehabilitation training plan. Besides, it is agreed by physicians and therapists that the device is easy-to-use, robust and has good real-time performance. The monitoring device thus holds the promise of boosting the development of digitalized rehabilitation medicine.

A Portable Wearable Inertial System for Rehabilitation Monitoring and Evaluation of Patients With Total Knee Replacement.

Knee osteoarthritis is a degenerative disease, which greatly affects the daily life of patients. Total knee replacement (TKR) is the most common method to treat knee joint disorders and relieve knee pain. Postoperative rehabilitation exercise is the key to restore knee joint function. However, there is a lack of a portable equipment for monitoring knee joint activity and a systematic assessment scheme. We have developed a portable rehabilitation monitoring and evaluation system based on the wearable inertial unit to estimate the knee range of motion (ROM). Ten TKR patients and ten healthy adults are recruited for the experiment, then the system performance is verified by professional rehabilitation equipment Baltimore Therapeutic Equipment (BTE) Primus RS. The average absolute difference between the knee ROM and BTE Primus RS of healthy subjects and patients ranges from 0.16° to 4.94°. In addition, the knee ROM of flexion-extension and gait activity between healthy subjects and patients showed significant differences. The proposed system is reliable and effective in monitoring and evaluating the rehabilitation progress of patients. The system proposed in this work is expected to be used for long-term effective supervision of patients in clinical and dwelling environments.