Automation of the Timed Up and Go Test Using a Doppler Radar System for Gait and Balance Analysis in Elderly People.

The timed up and go (TUG) test is a simple, valid, and reliable clinical tool that is widely used to assess mobility in elderly people. Several research studies have been conducted to automate the TUG test using wearable sensors or motion-tracking systems. Despite their promising results, the adopted technological systems present inconveniences in terms of acceptability and privacy protection. In this work, we propose to overcome these problems by using a Doppler radar system set into the backrest of a chair in order to automate the TUG test and extract additional information from its phases (i.e., transfer, walk, and turn). We intend to segment its phases and extract spatiotemporal gait parameters automatically. Our methodology is mainly based on a multiresolution analysis of radar signals. We proposed a segmentation technique based on the extraction of limbs oscillations signals through a semisupervised machine learning approach, on the one hand, and the application of the DARC algorithm on the other hand. Once the speed signals of torso and limbs oscillations were detected, we suggested estimating 14 gait parameters. All our approaches were validated by comparing outcomes to those obtained from a reference Vicon system. High correlation coefficients were obtained by comparing the speed signals of the torso (ρ=0.8), the speed signals of limbs oscillations (ρ=0.91), the initial and final indices of TUG phases (ρ=0.95), and the extracted parameters (percentage error < 4.8) obtained after radar signal processing to those obtained from the Vicon system.

Eye Recognition by YOLO for Inner Canthus Temperature Detection in the Elderly Using a Transfer Learning Approach.

Early detection of physical frailty and infectious diseases in seniors is important to avoid any fatal drawback and promptly provide them with the necessary healthcare. One of the major symptoms of viral infections is elevated body temperature. In this work, preparation and implementation of multi-age thermal faces dataset is done to train different "You Only Look Once" (YOLO) object detection models (YOLOv5,6 and 7) for eye detection. Eye detection allows scanning for the most accurate temperature in the face, which is the inner canthus temperature. An approach using an elderly thermal dataset is performed in order to produce an eye detection model specifically for elderly people. An application of transfer learning is applied from a multi-age YOLOv7 model to an elderly YOLOv7 model. The comparison of speed, accuracy, and size between the trained models shows that the YOLOv7 model performed the best (Mean average precision at Intersection over Union of 0.5 (mAP@.5) = 0.996 and Frames per Seconds (FPS) = 150). The bounding box of eyes is scanned for the highest temperature, resulting in a normalized error distance of 0.03. This work presents a fast and reliable temperature detection model generated using non-contact infrared camera and a deep learning approach.

An Evidential Framework for Localization of Sensors in Indoor Environments.

Indoor localization has several applications ranging from people tracking and indoor navigation, to autonomous robot navigation and asset tracking. We tackle the problem as a zoning localization where the objective is to determine the zone where the mobile sensor resides at any instant. The decision-making process in localization systems relies on data coming from multiple sensors. The data retrieved from these sensors require robust fusion approaches to be processed. One of these approaches is the belief functions theory (BFT), also called the Dempster-Shafer theory. This theory deals with uncertainty and imprecision with a theoretically attractive evidential reasoning framework. This paper investigates the usage of the BFT to define an evidence framework for estimating the most probable sensor's zone. Real experiments demonstrate the effectiveness of this approach and its competence compared to state-of-the-art methods.

A Systematic Review of Thirty-One Assessment Tests to Evaluate Mobility in Older Adults.

Assessments of gait, balance, and transfer in elderly people play a valuable role in maintaining healthy aging and preventing a decline in mobility. Several evaluation tools have been proposed; however, clinicians should select the most accurate ones wisely, based on numerous criteria. This systematic review aims to identify all applicable elderly mobility assessment tests and show their measurement properties with as much detail as possible. Initially, a broad search was performed. Articles were screened based on their titles and abstracts, and only studies published in English were considered. Based on our inclusion and exclusion criteria, 31 assessment tests evaluating the mobility of healthy elderly people were found. Then, further searches were completed to identify the measurement properties of each test. These characteristics include the origin and year of establishment, several practicality factors, and validity. The analysis of our outcomes illustrates the similarities and differences between the identified tests.

In-home physical frailty monitoring: relevance with respect to clinical tests.

BACKGROUND: Frailty detection and remote monitoring are of major importance for slowing down, and/or even stopping the frailty process in home-dwelling older people. Taking the Fried's criteria as a reference, this work aims to compare the results produced by a technological set (ARPEGE Pack) with those obtained by usual clinical tests, as well as to discuss the ability of the Pack to be used for long-run frailty remote monitoring. METHODS: 194 participants were given a number of geriatric tests and asked to make use of the ARPEGE technological tools as well as reference clinical tools to feed Fried's indicators. Spearman or Pearson's correlation coefficients were used to compare the ARPEGE results to the reference ones, depending on data statistical characteristics. RESULTS: Good correlations were obtained for measurements of weight (0.99), grip strength (0.89) and walking speed (0.79). Results are much less satisfactory for evaluation of physical activity and exhaustion (Spearman correlation coefficients 0.25 and 0.41, respectively). CONCLUSION: Correlations regarding weight, grip strength and walking speed confirm the validity of the data produced by the ARPEGE Pack to feed Fried's criteria. Assessing activity level and exhaustion from an abbreviated questionnaire is still questionable. However, for long-run monitoring other methods of evaluation can be explored. Beyond the quantitative results, the ARPEGE Pack has been proved to be acceptable and motivating in such a long-term frailty monitoring.

Gait Speed Measurement using a Doppler Radar Sensor for In-Home Functional Capacity Tests.

Gait speed is a simple physical function measure associated with key outcomes in the elderly population. Several tests are realized in order to assess the functional capacity of people. For an in-home monitoring of the functional capacity, we propose to use a Doppler radar sensor in order to continuously measure the gait speed of elderly people. We discuss at first how the gait speed is evaluated using the Doppler radar. We note three different phases in the gait speed, namely an acceleration zone, a measured-gait zone, and a deceleration zone. We thus provide a segmentation of the walking in order to automatically distinguish these zones. Experiments are conducted on ten subjects with three different paces in a total of 180 walking patterns. The gait speed obtained by the radar sensor is validated using a Vicon motion-capture system, with a correlation equal to 0.9788. We report an enhancement of 20% in measuring the gait speed as compared to traditional techniques, while removing the need for acceleration and deceleration zones.

Reliability of the Balance Quality Tester (BQT) for balance quality measurement.

Balance quality measurement is a key element in the evaluation of numerous conditions, including frailty. Four parameters were extracted from the balance quality assessment for older subjects: Rising Rate (RR), Duration of the stabilization segment (ZD), Stabilogram Area (SA) and Average Velocity of the Trajectory (TV). These are then scored and weighted, thus creating an overall indicator of balance quality. The reliability, the absolute reliability and the minimum difference of the four parameters were evaluated using the intra-class correlation coefficient (ICC), the standard error measurement (SEM) and the Minimal Detectable Change (MDC), respectively. Reproducibility was very high, with ICC values of 0.83, 0.85, 0.88 and 0.95 for RR, ZD, SA and TV, respectively. These results revealed that the parameters are a reliable measure for evaluating balance quality measurement.

Doppler Radar System for In-Home Gait Characterization using Wavelet Transform Analysis.

The evaluation of walking speed plays an important role in gerontology as it reflects the health and functional status of older people. In this paper, we propose the use of a Doppler radar system with continuous wavelet transform (CWT) analysis for in-home gait characterization. A methodology based on an accurate 3D motion-capture camera system (Vicon) has been developed in order to validate the suitable mother wavelet. The CWT analysis with several mother wavelets has been applied to our experimental Doppler radar signals. The Pearson Correlation coefficient (ρ) has been computed between the gait speed signals obtained from the radar and those obtained from the Vicon system. Our outcomes suggest the use of Daubechies5 and Symlets7 wavelets giving a ρ values of 0.86 and 0.85 respectively with a mean square error value less than 0.05 m/s in comparison with the correct gait speed value.

Identification of the period of stability in a balance test after stepping up using a simplified cumulative sum.

Falls are a major cause of death in older people. One method used to predict falls is analysis of Centre of Pressure (CoP) displacement, which provides a measure of balance quality. The Balance Quality Tester (BQT) is a device based on a commercial bathroom scale that calculates instantaneous values of vertical ground reaction force (Fz) as well as the CoP in both anteroposterior (AP) and mediolateral (ML) directions. The entire testing process needs to take no longer than 12 s to ensure subject compliance, making it vital that calculations related to balance are only calculated for the period when the subject is static. In the present study, a method is presented to detect the stabilization period after a subject has stepped onto the BQT. Four different phases of the test are identified (stepping-on, stabilization, balancing, stepping-off), ensuring that subjects are static when parameters from the balancing phase are calculated. The method, based on a simplified cumulative sum (CUSUM) algorithm, could detect the change between unstable and stable stance. The time taken to stabilize significantly affected the static balance variables of surface area and trajectory velocity, and was also related to Timed-up-and-Go performance. Such a finding suggests that the time to stabilize could be a worthwhile parameter to explore as a potential indicator of balance problems and fall risk in older people.

Balance quality assessment as an early indicator of physical frailty in older people.

Frailty is an increasingly common geriatric condition that results in an increased risk of adverse health outcomes such as falls. The most widely-used means of detecting frailty is the Fried phenotype, which includes several objective measures such as grip strength and gait velocity. One method of screening for falls is to measure balance, which can be done by a range of techniques including the assessment of the Centre of Pressure (CoP) during a balance assessment. The Balance Quality Tester (BQT) is a device based on a commercial bathroom scale that can evaluate balance quality. The BQT provides instantaneously the position of the CoP (stabilogram) in both anteroposterior (AP) and mediolateral (ML) directions and can estimate the vertical ground reaction force. The purpose of this study was to examine the relationship between balance quality assessment and physical frailty. Balance quality was compared to physical frailty in 186 older subjects. Rising rate (RR) was slower and trajectory velocity (TV) was higher in subjects classified as frail for both grip strength and gait velocity (p<;0.05). Balance assessment could be used in conjunction with functional tests of grip strength and gait velocity as a means of screening for frailty.

Development of a monitoring system for physical frailty in independent elderly.

Frailty is of increasing concern due to the associated decrease in independence of elderly who suffer from the condition. An innovative system was designed in order to objectively quantify the level of frailty based on a series of remote tests, each of which used objects similar to those found in peoples' homes. A modified ball, known as the Grip-ball was used to evaluate maximal grip force and exhaustion during an entirely remote assessment. A smartphone equipped with a tri-axial accelerometer was used to estimate gait velocity and physical activity level. Finally, a bathroom scale was used to assess involuntary weight loss. The smart phone processes all of the data generated, before it is transferred to a remote server where the user, their entourage, and any medical professionals with authorization can access the data. This innovative system could enable the onset of frailty to be detected early, thus giving sufficient time for a targeted intervention program to be implemented, thereby increasing independence for elderly users.

Estimation of grip force using the Grip-ball dynamometer.

The Grip-ball is an innovative device that has been designed to measure grip strength. The Grip-ball consists of an airtight ball that contains a pressure sensor and Bluetooth communication system. The Grip-ball can be inflated to different initial pressures, with data available continuously in real time. The aim of this study was to build a model to predict the force applied to the Grip-ball dynamometer based only on the pressure measured by the Grip-ball and its initial pressure. Forces ranging from 2 to 70 kg were applied to a hybrid version of the device for 10 different initial pressures, ranging from atmospheric pressure of 100 kPa through to 190 kPa. A model was constructed to predict applied force, with force as a function of the initial pressure and the pressure measured. The error of the model was calculated as 1.29 kg across all initial pressures and forces applied. The results of the study are comparable with the errors observed for the gold standard in grip force measurement, the Jamar dynamometer. The best results for force prediction were obtained over the range in which frailty is typically detected. The Grip-ball will now be tested using a large population in order to establish clinical norms.

Reliability and validity of the Grip-Ball dynamometer for grip-strength measurement.

Grip-strength measurement is a key element in the evaluation of numerous conditions including frailty. An innovative grip-strength evaluation tool, the Grip-Ball has been developed for remote assessment of grip-strength. The Grip-Ball is an airtight ball that can be inflated to different pressures, thus varying the stiffness of the ball and the grip-strength dynamics. Three different initial pressures of 100, 125, and 150 kPa were evaluated in respect to reliability and validity, when compared to the Jamar. Reliability was very high, with ICC values of 0.95, 0.98, and 0.99 for 100, 125, and 150 kPa, respectively. The new device was highly correlated with the force measured using the Jamar for all initial pressures (r= 0.88, 0.93, and 0.93 for 100, 125, and 150 kPa, respectively). The possibility of varying the initial pressure would enable the Grip-Ball to be used for standard grip-strength testing and rehabilitation, while still maintaining high reliability and validity.