scholarly journals Validation of the Actibelt® speed measurement in patients with dizziness and vertigo

2016 ◽  
Author(s):  
Valentin Rampmaier ◽  
Fabian Schenkel ◽  
Martin Daumer ◽  
Roman Schniepp
Keyword(s):  
Control Variable ◽  
Speed Estimation ◽  
Accelerometer Data ◽  
Laboratory Environment ◽  
Promising Tool ◽  
Speed Measurement ◽  
Risk Of Falls ◽  
Walking Velocity ◽  
Walking Speeds ◽  
Cerebellar Disorders

Walking velocity is an important control variable in gait disorders due to sensory or cerebellar disfunction. Non-preferred walking speeds are closely linked to a higher risk of falls. A compensation strategy of patients to avoid these speed sectors can be assumed. So far speed measurements are only possible in a laboratory environment. Actibelt® is a promising tool that allows speed estimation based on accelerometer data. The used algorithms have not been validated for patients with sensory or cerebellar disorders.

scholarly journals Validation of the Actibelt® speed measurement in patients with dizziness and vertigo

2016 ◽  
Author(s):  
Valentin Rampmaier ◽  
Fabian Schenkel ◽  
Martin Daumer ◽  
Roman Schniepp
Keyword(s):  
Control Variable ◽  
Speed Estimation ◽  
Accelerometer Data ◽  
Laboratory Environment ◽  
Promising Tool ◽  
Speed Measurement ◽  
Risk Of Falls ◽  
Walking Velocity ◽  
Walking Speeds ◽  
Cerebellar Disorders

Walking velocity is an important control variable in gait disorders due to sensory or cerebellar disfunction. Non-preferred walking speeds are closely linked to a higher risk of falls. A compensation strategy of patients to avoid these speed sectors can be assumed. So far speed measurements are only possible in a laboratory environment. Actibelt® is a promising tool that allows speed estimation based on accelerometer data. The used algorithms have not been validated for patients with sensory or cerebellar disorders.

Changes in the Dynamic Stability of Walking in Active Healthy Older Adults Independent of Changes in Walking Speed

2008 ◽  
Author(s):  
Hyun Gu Kang ◽  
Jonathan B. Dingwell
Keyword(s):  
Older Adults ◽  
Young Adults ◽  
Dynamic Stability ◽  
Walking Speed ◽  
Age Groups ◽  
Leg Strength ◽  
Age Related ◽  
Increased Risk ◽  
Risk Of Falls ◽  
Walking Speeds

Older adults commonly walk slower, which many believe helps improve their walking stability. However, they remain at increased risk of falls. We investigated how differences in age and walking speed independently affect dynamic stability during walking, and how age-related changes in leg strength and ROM affected this relationship. Eighteen active healthy older and 17 younger adults walked on a treadmill for 5 minutes each at each of 5 speeds (80–120% of preferred). Local divergence exponents and maximum Floquet multipliers (FM) were calculated to quantify each subject’s responses to small inherent perturbations during walking. These older adults exhibited the same preferred walking speeds as the younger subjects (p = 0.860). However, these older adults still exhibited greater local divergence exponents (p<0.0001) and higher maximum FM (p<0.007) than young adults at all walking speeds. These older adults remained more unstable (p<0.04) even after adjusting for declines in both strength and ROM. In both age groups, local divergence exponents decreased at slower speeds and increased at faster speeds (p<0.0001). Maximum FM showed similar changes with speed (p<0.02). The older adults in this study were healthy enough to walk at normal speeds. However, these adults were still more unstable than the young adults, independent of walking speed. This greater instability was not explained by loss of leg strength and ROM. Slower speeds led to decreased instability in both groups.

Analysis of Pedestrian Gait and Perception-Reaction at Signal-Controlled Crosswalk Intersections

2000 ◽  
Vol 1705 (1) ◽  
pp. 20-25 ◽  
Author(s):  
Thomas F. Fugger ◽  
Bryan C. Randles ◽  
Anthony C. Stein ◽  
William C. Whiting ◽  
Brian Gallagher
Keyword(s):  
Steady State ◽  
High Speed ◽  
Real Life ◽  
Light Illumination ◽  
Acceleration Rate ◽  
Significant Difference ◽  
Pedestrian Accident ◽  
Walking Velocity ◽  
The Mean ◽  
Walking Speeds

Pedestrian accident analysis and reconstruction remain the most difficult areas for the accident analyst. Although data relating to average pedestrian walking speeds, perception-reaction, and pedestrian accident reconstruction can be found in the literature, proper pedestrian study data pertaining to real-life situations are lacking. Pedestrians were observed at signal-controlled crosswalk intersections, and their perception-reaction to the crosswalk signal, acceleration rate to reach constant walking velocity, and average walking speed once steady state velocity is achieved were determined. Experimental test data collected regarding pedestrian gait analysis, initiation, and steady state walking speeds are presented. “Real world” pedestrian observations were gathered at a variety of intersections, ranging from busy downtown intersections to suburban intersections throughout the greater Los Angeles area. Kinematic data on pedestrian movements were obtained using high-speed digital video. A high-speed video motion analysis system was used to reduce the data and to obtain the mean acceleration and time to steady state walking velocity. Perception-reaction data collected on 288 subjects show a significant percentage of the pedestrians initiating movement within 1 s of Walk light illumination. Some differences were observed when the state of anticipation was being considered, and these results are presented. The mean acceleration (0.14 ± 0.09 g) and steady state velocity (1.36 ± 0.24 m/s) values did not demonstrate a significant difference between males and females. The width of the street or initial state of anticipation did not have an effect on either mean acceleration values or steady state velocities.

scholarly journals Video-Tachometer Methodology for Wind Turbine Rotor Speed Measurement

Sensors ◽  
2020 ◽  
Vol 20 (24) ◽  
pp. 7314
Author(s):  
Francesco Natili ◽  
Francesco Castellani ◽  
Davide Astolfi ◽  
Matteo Becchetti
Keyword(s):  
Wind Turbine ◽  
Rotational Speed ◽  
Wind Farm ◽  
Turbine Rotor ◽  
Rotating Machinery ◽  
Speed Estimation ◽  
Rotor Speed ◽  
High Rotational Speed ◽  
Speed Measurement ◽  
Wind Turbine Rotor

The measurement of the rotational speed of rotating machinery is typically performed based on mechanical adherence; for example, in encoders. Nevertheless, it can be of interest in various types of applications to develop contactless vision-based methodologies to measure the speed of rotating machinery. In particular, contactless rotor speed measurement methods have several potential applications for wind turbine technology, in the context of non-intrusive condition monitoring approaches. The present study is devoted exactly to this problem: a ground level video-tachometer measurement technique and an image analysis algorithm for wind turbine rotor speed estimation are proposed. The methodology is based on the comparison between a reference frame and each frame of the video through the covariance matrix: a covariance time series is thus obtained, from which the rotational speed is estimated by passing to the frequency domain through the spectrogram. This procedure guarantees the robustness of the rotational speed estimation, despite the intrinsic non-stationarity of the system and the possible signal disturbances. The method is tested and discussed based on two experimental environments with different characteristics: the former is a small wind turbine model (with a 0.45 m rotor diameter) in the wind tunnel facility of the University of Perugia, whose critical aspect is the high rotational speed (up to the order of 1500 RPM). The latter test case is a wind turbine with a 44 m rotor diameter which is part of an industrial wind farm: in this case, the critical point regards the fact that measurements are acquired in uncontrolled conditions. It is shown that the method is robust enough to overcome the critical aspects of both test cases and to provide reliable rotational speed estimates.

Influence of Walking Speed and Severity of Knee Osteoarthritis on Medial Compartment Loading

2007 ◽  
Author(s):  
Joseph Zeni ◽  
Jill Higginson
Keyword(s):  
Knee Osteoarthritis ◽  
Walking Speed ◽  
Medial Compartment ◽  
Knee Adduction Moment ◽  
Inverse Dynamic ◽  
External Moment ◽  
Walking Velocity ◽  
Dynamic Techniques ◽  
Walking Speeds ◽  
External Knee Adduction Moment

Progression of knee osteoarthritis (OA) has been shown to occur in the presence of an increased load at the medial compartment [1]. Current gait analysis techniques allow researchers to use inverse dynamic techniques to calculate external knee adduction moments. These moments correlate to varus knee stresses and increased load in the medial knee compartment. These abnormal stresses have been hypothesized to play a role in the destruction of articular cartilage [2]. Previous authors have suggested that walking velocity will affect the adduction moment and that decreasing walking speed may reduce the maximal knee external moment during gait [3]. Based on these previous findings, we investigated various walking speeds in subjects with mild, moderate and severe OA and the effect on the external knee adduction moment.

scholarly journals A People-Counting and Speed-Estimation System Using Wi-Fi Signals

Sensors ◽  
2021 ◽  
Vol 21 (10) ◽  
pp. 3472
Author(s):  
Liping Tian ◽  
Liangqin Chen ◽  
Zhimeng Xu ◽  
Zhizhang (David) Chen
Keyword(s):  
Speed Estimation ◽  
Threshold Method ◽  
Nonlinear Fitting ◽  
Crowd Control ◽  
Speed Error ◽  
Estimation System ◽  
Dynamic Time ◽  
End Times ◽  
Walking Speeds ◽  
Accuracy Rates

Counting the number of people and estimating their walking speeds are essential in crowd control and flow. In this work, we propose a system that uses prevalent Wi-Fi signals to identify the number of people entering and leaving a room through a door. It selects the best subcarrier of Wi-Fi signals and applies the Hampel filter to remove outlier information first. Then, it employs a double threshold method to determine the start and end times of entering or leaving. Afterward, it compares the detected signals with the precollected database using the dynamic time-warping algorithm and determines the number of people. It uses a variance threshold method to identify the states of entering or leaving. It also employs a nonlinear fitting approach to calculate the walking speeds. The experiments show that, in a large empty laboratory, the accuracy rates in determining the number of people are 100% for one person, 81% for two persons, and 95% for three persons. In a small office, the accuracy rates for detecting the number of people are 98% for one or two persons, 82% for three persons, 93% for four, and 75% for five persons. For the walking speed estimation, the accuracy rate for a speed error of less than 0.2410 m/s is 75% for a single person.

EXPLORATION OF VIBROTACTILE BIOFEEDBACK STRATEGIES TO INDUCE STANCE TIME ASYMMETRIES

2021 ◽  
Vol 5 (1) ◽  
Author(s):  
Rafael Escamilla-Nunez ◽  
Harry Sivasambu ◽  
Jan Andrysek
Keyword(s):  
Control Variable ◽  
Short Term ◽  
Gait Symmetry ◽  
Term Retention ◽  
Biofeedback System ◽  
Feedback Strategies ◽  
Stance Time ◽  
Walking Speeds ◽  
Future Work

BACKGROUND: Gait symmetry is the degree of equality of biomechanical parameters between limbs within a gait cycle. Human gait is highly symmetrical; however, in the presence of pathology, gait often lacks symmetry. Biofeedback (BFB) systems have demonstrated the potential to reduce gait asymmetry, improve gait function, and benefit overall long-term musculoskeletal health. OBJECTIVE(S): The aim of this study was to develop a BFB system and evaluate three unique BFB strategies, including bidirectional control – constant vibration (BC), bidirectional control – variable vibration (BV), and unidirectional control – variable vibration (UV) relevant to gait symmetry. The assessed feedback strategies were a combination of vibration frequency/amplitude levels, vibration thresholds, and vibrotactile stimuli from one and two vibrating motors (tactors). Learning effect and short-term retention were also assessed. METHODOLOGY: Testing was performed using a custom BFB system that induces stance time asymmetries to modulate temporal gait symmetry. The BFB system continuously monitors specific gait events (heel-strike and toe-off) and calculates the symmetry ratio, based on the stance time of both limbs to provide real-time biomechanical information via the vibrating motors. Overall walking performance of ten (n=10) able-bodied individuals (age 24.8 ± 4.4 years) was assessed via metrics of symmetry ratio, symmetry ratio error, walking speed, and motor's vibration percentages. FINDINGS: All participants utilized BFB somatosensory information to modulate their symmetry ratio. UV feedback produced a greater change in symmetry ratio, and it came closer to the targeted symmetry ratio. Learning or short-term retention effects were minimal. Walking speeds were reduced with feedback compared to no feedback; however, UV walking speeds were significantly faster compared to BV and BC. CONCLUSION: The outcomes of this study provide new insights into the development and implementation of feedback strategies for gait retraining BFB systems that may ultimately benefit individuals with pathological gait. Future work should assess longer-term use and long-term learning and retention effects of BFB systems in the populations of interest. Layman's Abstract Healthy walking is usually highly symmetrical with the same movements occurring on both sides of the body. However, certain disorders can cause abnormal and asymmetrical walking movements. Biofeedback can improve the movements during walking. This study used a custom biofeedback system to test three ways of applying biofeedback including having one and two motors that vibrated in unique ways. The biofeedback system was set up to guide participants to change their normal walking pattern to be less symmetrical. Walking movements of ten young able-bodied individuals were measured while walking with the biofeedback system. The results showed a change in walking symmetry for all participants. Using a single vibrating motor resulted in the greatest changes in walking symmetry. The changes in walking symmetry occurred only when using biofeedback, and walking patterns quickly returned to normal when the biofeedback was turned off. Overall, all feedback methods caused the users to walk slower than their typical walking speed. These findings provide important new information about the changes in walking caused by different biofeedback methods. Future work should evaluate long-term effects of biofeedback methods in the populations of interest. Article PDF Link: https://jps.library.utoronto.ca/index.php/cpoj/article/view/36744/28677 How To Cite: Escamilla-Nunez R, Sivasambu H, Andrysek J. Exploration of vibrotactile biofeedback strategies to induce stance time asymmetries. Canadian Prosthetics & Orthotics Journal. 2022; Volume 5, Issue 1, No.2. https://doi.org/10.33137/cpoj.v5i1.36744 Corresponding Author: Rafael Escamilla-Nunez, Institute of Biomedical Engineering, University of Toronto, Toronto, Canada.E-Mail: [email protected] ID: https://orcid.org/0000-0002-2739-878X

scholarly journals Barriers to the Initiation of Home Modifications for Older Adults for Fall Prevention

2021 ◽  
Vol 12 ◽  
pp. 215145932110021
Author(s):  
Jessica M. Wiseman ◽  
David S. Stamper ◽  
Elizabeth Sheridan ◽  
Jeffrey M. Caterino ◽  
Catherine C. Quatman-Yates ◽  
...  
Keyword(s):  
Older Adults ◽  
Socioeconomic Status ◽  
Low Socioeconomic Status ◽  
Cost Effective ◽  
Cross Sectional ◽  
Low Socioeconomic ◽  
Promising Tool ◽  
Home Modifications ◽  
Risk Of Falls ◽  
Areas Of Interest

Introduction: Home modifications are associated with decreased risk for falls and facilitate safe aging in place. The purpose of this study was to identify barriers to procurement of home modifications for older adults. Materials and Methods: Cross-sectional interviews by 2 separate (1 male and 1 female) researchers in a Midwestern city of home repair (“handyman”) and construction businesses within 15 miles of the areas of interest (neighborhood with a high socioeconomic status and neighborhood with low socioeconomic status) with a publicly listed phone number (n = 98). Estimated cost, earliest date of installation, and duration for a home modification project (installation of 3 grab bars) were collected. Results: At least 1 response was attained only 43% of the time (n = 42), and residential grab bar installations were not provided by most businesses (n = 24). The average quote for materials and labor was $394.31 (range $125-$1300). Five of the 7 businesses that responded to both researchers with the same representative differed in cost estimates, generally offering a reduced quote for the low socioeconomic status neighborhood by as much as $300. Quotes provided to the female researcher were also higher than those obtained by the male researcher by about $30 regardless of socioeconomic status. The average wait for home modifications was 23 days and the average anticipated duration of the project was 2.6 hours. Discussion: There are financial and procedural barriers to accessing home modifications for older adults who independently attempt to acquire them. There is a need for pathways in clinical and community settings to reduce barriers to home modifications to reduce the risk of falls. Conclusion: Home modifications are a promising tool to reduce falls and fall-related injuries in older adults. However, further work to identify cost-effective and timely options to reduce acquisition barriers is necessary to leverage the preventive power of home modifications.

Speed Estimation using Smartphone Accelerometer Data

2019 ◽  
Vol 2673 (3) ◽  
pp. 65-73
Author(s):  
Ilyas Ustun ◽  
Mecit Cetin
Keyword(s):  
Kinetic Theory ◽  
White Noise ◽  
Calibration Method ◽  
Speed Estimation ◽  
Vehicle Speed ◽  
Accelerometer Data ◽  
Model Accuracy ◽  
Lower Margin ◽  
Sample Data ◽  
Gravity Component

This paper is focused on developing an algorithm to estimate vehicle speed from accelerometer data generated by an onboard smartphone. The kinetic theory tells that the integration of acceleration gives the speed of a vehicle. Thus, the integration of the acceleration values collected with the smartphone in the direction of motion would theoretically yield the speed. However, speed estimation by the integration of accelerometer data will not yield accurate results, as the accelerometer data in the direction of motion is not pure acceleration, but involves white noise, phone sensor bias, vibration, gravity component, and other effects. To account for these sources of noise and error, a calibration method that can adjust the speed at certain times or points is needed. The exact times when the vehicle stops and starts are identified and used to calibrate the estimated speed. Based on the collected sample data, the proposed method yields that the estimated speed is on average within 10 mph of the actual speed, with a lower margin at the street-level driving. This suggests that with more information to calibrate the speed, the model accuracy can be improved further.

COMPREHENSIVE CHARACTERIZATION OF GAIT VARIABILITY IN PATIENTS WITH KNEE OSTEOARTHRITIS FOR ALTERED VELOCITIES

2018 ◽  
Vol 18 (04) ◽  
pp. 1850041
Author(s):  
NARGESS MATINAZAD ◽  
ALI ESTEKI ◽  
HAMED GHOMASHCHI
Keyword(s):  
Knee Osteoarthritis ◽  
Angular Displacement ◽  
Gait Pattern ◽  
Gait Variability ◽  
Human Gait ◽  
Control Group ◽  
Largest Lyapunov Exponent ◽  
Knee Oa ◽  
Walking Velocity ◽  
Walking Speeds

This study focuses on quantifying the alterations in human gait variability in individuals with knee Osteoarthritis (OA). To assess the stride-to-stride variation, estimating the dynamical stability discloses the encrypted behavior of the locomotion system, at times facing perturbations, and for that the Largest Lyapunov Exponent is extracted for both Short ([Formula: see text]) and Long ([Formula: see text]) term. Information about the complexity of movement further bolsters the variation-driven conclusions which are calculated for Correlation Index and Kolmogorov–Sinai (K-S) entropy. Using gait analysis, knee angular displacement is the considered data tested for different walking speeds. In the result, [Formula: see text] revealed significant differences between the groups and their walking velocities while [Formula: see text] failed to represent any distinguishable differences. In contrast to the control group, increases in the walking velocity did not affect the amount of locomotion variability for the patients. The stride features also verified the vicissitudes in the gait pattern of knee OA suffering individuals.

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