Evaluation of an ambulatory system for gait analysis in hip osteoarthritis and after total hip replacement

Effects of device-performed and manual hip traction and vibration therapy in older adults with symptomatic hip osteoarthritis: A randomized single-blind controlled trial

BACKGROUND

Traction-and-vibration-therapy (TVT) relieves pain in participants with hip osteoarthritis. Hip TVT is usually performed manually by the physiotherapist.

OBJECTIVE

A medical device was developed to perform hip-TVT in order to investigate effects on hip disability, pain intensity, recovery of balance and functional mobility in older adults with hip osteoarthritis and also to reduce physiotherapists' workload and help standardize treatment of hip TVT.

METHODS

In a block-randomized 3-month controlled trial involving 28 older adult participants with symptomatic primary hip osteoarthritis (SPHOA), one group (n= 10) received device-performed TVT, one (n= 10) manual TVT, and one (n= 8) sham/placebo therapy. Hip disability (Harris Hip Score), pain intensity (visual-analog-scale), recovery of balance and gait (Functional Gait Assessment) and functional mobility (Timed-Up-and-Go-test) were assessed at baseline, after 3 weeks without intervention, and after 3-month intervention.

RESULTS

The Device TVT and Manual TVT groups exhibited superior outcomes compared to the Placebo group in terms of hip disability (p= 0.005 and p< 0.001, respectively), pain intensity (p= 0.002 and p< 0.001, respectively), and functional mobility (TUG) (p= 0.012 and p= 0.011, respectively). Furthermore, the recovery of balance and gait (FGA) showed a significant improvement in the Device TVT group when compared to the Placebo group (p= 0.043). The effect sizes ranged from 0.17 to 0.51, indicating moderate to large effects.

CONCLUSION

Device-performed-TVT is comparable to manual hip-TVT for reducing pain and improving mobility in older adults with SPHOA, and may be beneficial in terms of reducing physiotherapists' workload and better therapy standardization.

Effects of hip osteoarthritis on lower body joint kinematics during locomotion tasks: a systematic review and meta-analysis

Introduction

Motion analysis can be used to gain information needed for disease diagnosis as well as for the design and evaluation of intervention strategies in patients with hip osteoarthritis (HOA). Thereby, joint kinematics might be of great interest due to their discriminative capacity and accessibility, especially with regard to the growing usage of wearable sensors for motion analysis. So far, no comprehensive literature review on lower limb joint kinematics of patients with HOA exists. Thus, the aim of this systematic review and meta-analysis was to synthesise existing literature on lower body joint kinematics of persons with HOA compared to those of healthy controls during locomotion tasks.

Methods

Three databases were searched for studies on pelvis, hip, knee and ankle kinematics in subjects with HOA compared to healthy controls during locomotion tasks. Standardised mean differences were calculated and pooled using a random-effects model. Where possible, subgroup analyses were conducted. Risk of bias was assessed with the Downs and Black checklist.

Results and Discussion

A total of 47 reports from 35 individual studies were included in this review. Most studies analysed walking and only a few studies analysed stair walking or turning while walking. Most group differences were found in ipsi- and contralateral three-dimensional hip and sagittal knee angles with reduced ranges of motion in HOA subjects. Differences between subjects with mild to moderate and severe HOA were found, with larger effects in severe HOA subjects. Additionally, stair walking and turning while walking might be promising extensions in clinical gait analysis due to their elevated requirements for joint mobility. Large between-study heterogeneity was observed, and future studies have to clarify the effects of OA severity, laterality, age, gender, study design and movement execution on lower limb joint kinematics.

Systematic Review Registration

PROSPERO (CRD42021238237).

Game-based intradialytic non-weight-bearing exercise training on gait speed and balance in older adults with diabetes: a single-blind randomized controlled trial

Older adults with diabetes receiving hemodialysis have impaired gait speed and balance compared to the general population, which have been associated with increased risks of falls and mortality. This study evaluated the effectiveness of a game-based intradialytic exercise training program (iExergame) on improving gait speed and balance. This was a single-blind randomized controlled trial. The intervention group (IG) received iExergame training using real-time audiovisual feedback with wearable inertial sensors. The control group (CG) received conventional training without any technology. Both trainings were intradialytic, non-weight-bearing, and used ankle range of motion. Gait and balance parameters were collected at baseline and 4-week follow-up. Data from 70 adults (age 64.2 ± 9.0 years) were analyzed. Compared to the CG, the IG showed greater changes between baseline and 4-week follow-up in several parameters. Gait parameters included faster speeds and longer stride lengths, particularly during dual task walking (p < 0.050). Balance parameters included reductions in center of mass (p = 0.004), ankle (p < 0.001), and hip (p = 0.010) sways during semi-tandem stance, particularly in users of assistive devices. iExergame training could improve gait speed and balance in this population and might be an option to increase intradialytic exercise adherence while reducing burdens of exercise administration.

Present and future of gait assessment in clinical practice: Towards the application of novel trends and technologies

Background

Despite being available for more than three decades, quantitative gait analysis remains largely associated with research institutions and not well leveraged in clinical settings. This is mostly due to the high cost/cumbersome equipment and complex protocols and data management/analysis associated with traditional gait labs, as well as the diverse training/experience and preference of clinical teams. Observational gait and qualitative scales continue to be predominantly used in clinics despite evidence of less efficacy of quantifying gait.

Research objective

This study provides a scoping review of the status of clinical gait assessment, including shedding light on common gait pathologies, clinical parameters, indices, and scales. We also highlight novel state-of-the-art gait characterization and analysis approaches and the integration of commercially available wearable tools and technology and AI-driven computational platforms.

Methods

A comprehensive literature search was conducted within PubMed, Web of Science, Medline, and ScienceDirect for all articles published until December 2021 using a set of keywords, including normal and pathological gait, gait parameters, gait assessment, gait analysis, wearable systems, inertial measurement units, accelerometer, gyroscope, magnetometer, insole sensors, electromyography sensors. Original articles that met the selection criteria were included.

Results and significance

Clinical gait analysis remains highly observational and is hence subjective and largely influenced by the observer's background and experience. Quantitative Instrumented gait analysis (IGA) has the capability of providing clinicians with accurate and reliable gait data for diagnosis and monitoring but is limited in clinical applicability mainly due to logistics. Rapidly emerging smart wearable technology, multi-modality, and sensor fusion approaches, as well as AI-driven computational platforms are increasingly commanding greater attention in gait assessment. These tools promise a paradigm shift in the quantification of gait in the clinic and beyond. On the other hand, standardization of clinical protocols and ensuring their feasibility to map the complex features of human gait and represent them meaningfully remain critical challenges.

Three-dimensional foot trajectory in female patients with end-stage hip osteoarthritis during walking

Osteoarthritis (OA) is a risk factor for falls. To decrease the fall risk, it is important to evaluate the detailed features of the gait of patients with OA. This study aimed to investigate the spatio-temporal parameters of gait in patients with end-stage hip OA, especially foot trajectory. We measured normal speed gait in patients with hip OA and in healthy controls (HCs) using inertial measurement units attached to shanks. The stride lengths in the affected and unaffected sides in the patients with hip OA were shorter than those in the HCs, but the position of maximum foot clearance was not significantly different between the two groups. The patients with hip OA compensated the position of maximum foot clearance to avoid fall risk. The horizontal plane foot trajectory in patients with hip OA suggests that the lateral bending of the trunk during walking, which is frequently seen in them, was a result of the lateral distance at swing down being located significantly more medially on the unaffected side than on the affected side. Herein, a new gait parameter of lateral distance at swing was discovered by a detailed evaluation of three-dimensional foot trajectory of female patients with end-stage hip OA.

Early postoperative relationship between patient-reported outcome measures and gait biomechanical factors after total hip arthroplasty

BACKGROUND

Patient-reported outcome measures (PROMs) have recently been considered as indicating clinical outcomes after total hip arthroplasty (THA). Although various factors are reportedly associated with post-THA and PROMs, the relationship with gait parameters, which are objective assessment factors after THA, remains unclear.

RESEARCH QUESTION

What is the relationship between PROMs and gait biomechanical factors four weeks after THA?

METHODS

Forty-five patients (six men and 39 women) who underwent THA were included. Three-dimensional gait analysis was performed four weeks post-THA; joint angle, internal moment, and power of the lower extremity at the first and second peaks of the vertical component of the floor reaction force were assessed for the operated side. PROMs were evaluated using the Japanese Orthopedic Association Hip Disease Evaluation Questionnaire (JHEQ). The relationship between the JHEQ score and extracted gait parameters was analyzed using gender and gait speed as control factors.

RESULTS

For the JHEQ sub-domain, movement was positively correlated with the internal knee extension moment values at the first peak (r = 0.347). There was no significant correlation between JHEQ and the internal hip abduction moment value at the first peak. Mental status was negatively correlated with the hip flexion angle value at the second peak (r = -0.373), and positively correlated with the hip flexion moment value (r = 0.348). Total JHEQ scores and mental status were negatively correlated with the power of hip flexion value at the second peaks, respectively (r = -0.316, -0.444).

SIGNIFICANCE

The results of this study may provide recovery guidelines to be used as an index for gait assessment in the early post-THA period. Further studies are needed to verify whether gait parameters can improve PROMs in the early post-THA period.

Digital Biomarkers of Cognitive Frailty: The Value of Detailed Gait Assessment Beyond Gait Speed

BACKGROUND

Cognitive frailty (CF), defined as the simultaneous presence of cognitive impairment and physical frailty, is a clinical symptom in early-stage dementia with promise in assessing the risk of dementia. The purpose of this study was to use wearables to determine the most sensitive digital gait biomarkers to identify CF.

METHODS

Of 121 older adults (age = 78.9 ± 8.2 years, body mass index = 26.6 ± 5.5 kg/m2) who were evaluated with a comprehensive neurological exam and the Fried frailty criteria, 41 participants (34%) were identified with CF and 80 participants (66%) were identified without CF. Gait performance of participants was assessed under single task (walking without cognitive distraction) and dual task (walking while counting backward from a random number) using a validated wearable platform. Participants walked at habitual speed over a distance of 10 m. A validated algorithm was used to determine steady-state walking. Gait parameters of interest include steady-state gait speed, stride length, gait cycle time, double support, and gait unsteadiness. In addition, speed and stride length were normalized by height.

RESULTS

Our results suggest that compared to the group without CF, the CF group had deteriorated gait performances in both single-task and dual-task walking (Cohen's effect size d = 0.42-0.97, p < 0.050). The largest effect size was observed in normalized dual-task gait speed (d = 0.97, p < 0.001). The use of dual-task gait speed improved the area under the curve (AUC) to distinguish CF cases to 0.76 from 0.73 observed for the single-task gait speed. Adding both single-task and dual-task gait speeds did not noticeably change AUC. However, when additional gait parameters such as gait unsteadiness, stride length, and double support were included in the model, AUC was improved to 0.87.

CONCLUSIONS

This study suggests that gait performances measured by wearable sensors are potential digital biomarkers of CF among older adults. Dual-task gait and other detailed gait metrics provide value for identifying CF above gait speed alone. Future studies need to examine the potential benefits of gait performances for early diagnosis of CF and/or tracking its severity over time.

The Differential Effect of First-Time Single-Point Cane Use between Healthy Young and Older Adults

BACKGROUND

Walking aids are often introduced to older adults to enable independent mobility. Single-point canes are the most common device used. Benefits are tempered by research suggesting that walking aids increase fall risk. A better understanding of the effect of walking aid use on gait performance is required.

OBJECTIVE

To evaluate differences in the effect of initial single-point cane use on gait between younger (YAs) and older adults (OAs).

DESIGN

Cross-sectional.

SETTING

Community-dwelling.

PARTICIPANTS

Twenty-six YAs (mean age ± standard deviation [SD]: 23.7 ± 2.8 years) and 25 OAs (mean age ± SD: 70.8 ± 14.1 years) participated. Inclusion criteria were 18 to 35 years of age for YAs or ≥50 years for OAs, be able to ambulate unassisted, and without any condition affecting mobility.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURE(S)

Gait velocity and stride time variability under different walking path configurations (straight path, Groningen Meander Walking Test, Figure-of-8 Walk Test) and conditions (unassisted walking, walking with a single-point cane, and walking with a single-point cane while completing a cognitive task) were recorded in a laboratory. The arithmetic task of subtracting 1s from 100 was used as the secondary cognitive task. Data analysis included separate three-way mixed analyses of variance (ANOVAs; path/condition/group).

RESULTS

There was a statistically significant two-way interaction between walking path and condition for velocity (P < .001, ω²  = 0.03) and stride time variability (P = .032, ω²  = 0.02). In addition, a significant main effect of group was also observed (velocity: P = .004, ω²  = 0.07; stride time variability: P = .001, ω²  = 0.09).

CONCLUSIONS

Using a single-point cane decreased velocity and increased stride time variability in both YAs and OAs. However, the cognitive load and effect on gait of initial cane use was not different between age groups. Standardized guidelines aimed at facilitating a client's transition toward the safe use of a walking aid are needed. Future research should evaluate if training can mitigate some of the adverse changes to gait stability observed with initial walking aid use.

IMU-Based Gait Normalcy Index Calculation for Clinical Evaluation of Impaired Gait

Inertial measurement units (IMU) have been used for gait analysis in many clinical studies, as a more convenient, low cost and less restricted alternative to the laboratory-based motion capture systems or instrumented walkways. Spatial-temporal gait parameters such as gait cycle duration and stride length calculated from the IMUs were often used in these studies for evaluating the impaired gait. However, the spatial-temporal information provided by IMUs is limited, and sometime suffers incomplete and less effective evaluation. In this study, we develop a novel IMU-based method for clinical gait evaluation. Nine gait variables including three spatial-temporal parameters and six kinematic parameters are extracted from two shank-mounted IMUs for quantifying patient's gait deviations. Based on those parameters, an IMU-based gait normalcy index (INI) is derived to evaluate the overall gait performance. Eight inpatient subjects with gait impairments caused by n-hexane neuropathy and ten healthy subjects were recruited. The proposed gait variables and INI were examined on the inpatients at three to five time instants during the rehabilitation process until being discharged. A comparison with healthy subjects and statistical analysis for the changes of gait variables and INI demonstrated that the proposed new set of gait variables and INI can provide adequate and effective information for quantifying gait abnormalities, and help understanding the progress of gait and effectiveness of therapy during rehabilitation process.

Wearable Inertial Sensors for Gait Analysis in Adults with Osteoarthritis-A Scoping Review

Our objective was to conduct a scoping review which summarizes the growing body of literature using wearable inertial sensors for gait analysis in lower limb osteoarthritis. We searched six databases using predetermined search terms which highlighted the broad areas of inertial sensors, gait, and osteoarthritis. Two authors independently conducted title and abstract reviews, followed by two authors independently completing full-text screenings. Study quality was also assessed by two independent raters and data were extracted by one reviewer in areas such as study design, osteoarthritis sample, protocols, and inertial sensor outcomes. A total of 72 articles were included, which studied the gait of 2159 adults with osteoarthritis (OA) using inertial sensors. The most common location of OA studied was the knee (n = 46), followed by the hip (n = 22), and the ankle (n = 7). The back (n = 41) and the shank (n = 40) were the most common placements for inertial sensors. The three most prevalent biomechanical outcomes studied were: mean spatiotemporal parameters (n = 45), segment or joint angles (n = 33), and linear acceleration magnitudes (n = 22). Our findings demonstrate exceptional growth in this field in the last 5 years. Nevertheless, there remains a need for more longitudinal study designs, patient-specific models, free-living assessments, and a push for "Code Reuse" to maximize the unique capabilities of these devices and ultimately improve how we diagnose and treat this debilitating disease.

Measuring gait kinematics in patients with severe hip osteoarthritis using wearable sensors

BACKGROUND

The popularity of inertial sensors in gait analysis is steadily rising. To date, an application of a wearable inertial sensor system for assessing gait in hip osteoarthritis (OA) has not been reported.

RESEARCH QUESTION

Can the known kinematic differences between patients with hip OA and asymptomatic control subjects be measured using the inertial sensor system RehaGait®?

METHODS

The patients group consisted of 22 patients with unilateral hip OA scheduled for total hip replacement. Forty-five age matched healthy control subjects served as control group. All subjects walked for a distance of 20 m at their self-selected speed. Spatiotemporal parameters and sagittal kinematics at the hip, knee, and ankle including range of motion (ROM) were measured using the RehaGait® system.

RESULTS

Patients with hip OA walked at a slower walking speed (-0.18 m/s, P < 0.001) and with shorter stride length (-0.16 m, P < 0.001), smaller hip ROM during stance (-11.6°, P < 0.001) and swing (-11.3°, P < 0.001) and smaller knee ROM during terminal stance and swing (-9.0° and-11.5°, P < 0.001). Patients had a smaller hip ROM during stance and swing and smaller knee ROM during terminal stance and swing in the affected compared to the unaffected side (P < 0.001).

SIGNIFICANCE

The differences in spatiotemporal and kinematic gait parameters between patients with hip OA and age matched control subjects assessed using the inertial sensor system agree with those documented for camera-based systems. Hence, the RehaGait® system can measure gait kinematics characteristic for hip OA, and its use in daily clinical practice is feasible.

Concurrent Validity, Test-Retest Reliability, and Sensitivity to Change of a Single Body-Fixed Sensor for Gait Analysis during Rollator-Assisted Walking in Acute Geriatric Patients

Body-fixed sensor (BFS) technology offers portable, low-cost and easy-to-use alternatives to laboratory-bound equipment for analyzing an individual's gait. Psychometric properties of single BFS systems for gait analysis in older adults who require a rollator for walking are, however, unknown. The study's aim was to evaluate the concurrent validity, test-retest-reliability, and sensitivity to change of a BFS (DynaPort MoveTest; McRoberts B.V., The Hague, The Netherlands) for measuring gait parameters during rollator-assisted walking. Fifty-eight acutely hospitalized older patients equipped with the BFS at the lower back completed a 10 m walkway using a rollator. Concurrent validity was assessed against the Mobility Lab (APDM Inc.; Portland, OR, USA), test-retest reliability over two trials within a 15 min period, and sensitivity to change in patients with improved, stable and worsened 4 m usual gait speed over hospital stay. Bland-Altman plots and intraclass correlation coefficients (ICC) for gait speed, cadence, step length, step time, and walk ratio indicate good to excellent agreement between the BFS and the Mobility Lab (ICC_2,1 = 0.87-0.99) and the repeated trials (ICC_2,1 = 0.83-0.92). Moderate to large standardized response means were observed in improved (gait speed, cadence, step length, walk ratio: 0.62-0.99) and worsened patients (gait speed, cadence, step time: -0.52 to -0.85), while those in stable patients were trivial to small (all gait parameters: -0.04-0.40). The BFS appears to be a valid, reliable and sensitive instrument for measuring spatio-temporal gait parameters during rollator-assisted walking in geriatric patients.

Coordination Pattern of the Thigh, Pelvic, and Lumbar Movements during the Gait of Patients with Hip Osteoarthritis

There are limited reports on segment movement and their coordination pattern during gait in patients with hip osteoarthritis. To avoid the excessive stress toward the hip and relevant joints, it is important to investigate the coordination pattern between these segment movements, focusing on the time series data. This study aimed to quantify the coordination pattern of lumbar, pelvic, and thigh movements during gait in patients with hip osteoarthritis and in a control group. An inertial measurement unit was used to measure the lumbar, pelvic, and thigh angular velocities during gait of 11 patients with hip osteoarthritis and 11 controls. The vector coding technique was applied, and the coupling angle and the appearance rate of coordination pattern in each direction were calculated and compared with the control group. Compared with the control group, with respect to the lumbar/pelvic segment movements, the patients with hip osteoarthritis spent more rates in anti-phase and lower rates in in-phase lateral tilt movement. With respect to the pelvic/thigh segment movements, the patients with hip osteoarthritis spent more rates within the proximal- and in-phases for lateral tilt movement. Furthermore, patients with osteoarthritis spent lower rates in the distal-phase for anterior/posterior tilt and rotational movement. Patients with hip osteoarthritis could not move their pelvic and thigh segments separately, which indicates the stiffness of the hip joint. The rotational movement and lateral tilt movements, especially, were limited, which is known as Duchenne limp. To maintain the gait ability, it seems important to pay attention to these directional movements.

Validity and reliability of wearable inertial sensors in healthy adult walking: a systematic review and meta-analysis

BACKGROUND

Inertial measurement units (IMUs) offer the ability to measure walking gait through a variety of biomechanical outcomes (e.g., spatiotemporal, kinematics, other). Although many studies have assessed their validity and reliability, there remains no quantitive summary of this vast body of literature. Therefore, we aimed to conduct a systematic review and meta-analysis to determine the i) concurrent validity and ii) test-retest reliability of IMUs for measuring biomechanical gait outcomes during level walking in healthy adults.

METHODS

Five electronic databases were searched for journal articles assessing the validity or reliability of IMUs during healthy adult walking. Two reviewers screened titles, abstracts, and full texts for studies to be included, before two reviewers examined the methodological quality of all included studies. When sufficient data were present for a given biomechanical outcome, data were meta-analyzed on Pearson correlation coefficients (r) or intraclass correlation coefficients (ICC) for validity and reliability, respectively. Alternatively, qualitative summaries of outcomes were conducted on those that could not be meta-analyzed.

RESULTS

A total of 82 articles, assessing the validity or reliability of over 100 outcomes, were included in this review. Seventeen biomechanical outcomes, primarily spatiotemporal parameters, were meta-analyzed. The validity and reliability of step and stride times were found to be excellent. Similarly, the validity and reliability of step and stride length, as well as swing and stance time, were found to be good to excellent. Alternatively, spatiotemporal parameter variability and symmetry displayed poor to moderate validity and reliability. IMUs were also found to display moderate reliability for the assessment of local dynamic stability during walking. The remaining biomechanical outcomes were qualitatively summarized to provide a variety of recommendations for future IMU research.

CONCLUSIONS

The findings of this review demonstrate the excellent validity and reliability of IMUs for mean spatiotemporal parameters during walking, but caution the use of spatiotemporal variability and symmetry metrics without strict protocol. Further, this work tentatively supports the use of IMUs for joint angle measurement and other biomechanical outcomes such as stability, regularity, and segmental accelerations. Unfortunately, the strength of these recommendations are limited based on the lack of high-quality studies for each outcome, with underpowered and/or unjustified sample sizes (sample size median 12; range: 2-95) being the primary limitation.

Gait analysis - Available platforms for outcome assessment

Movement or gait analysis has become a viable assessment tool not only used in sports science or basic biomechanical research, but has also expanded to be a very valuable instrument in clinical diagnostics, monitoring functional recovery and musculoskeletal rehabilitation. In this context, this method has long been an integral part solely in neurological disorders such as cerebral palsy. However, in the meantime the benefits have also become apparent in other medical areas, such as foot surgery, orthopaedic technology, or in patients after lower limb amputation. These procedures proved to better understand, objectify and quantify the individual causes of gait and movement disorders in order to optimize patient-specific therapy. Currently we are able to rely on a multitude of available measurement systems. These can either be used in everyday life for simple monitoring of one's own activity or to complement therapeutic approaches in the clinical and scientific environment. The following review highlights the various fields of movement analysis, including markerless motion capture, marker-based analysis, pedobarography and wearable sensors. Each of these areas presents its own field of application and potential usage as well as the advantages and disadvantages arising in this context. The following article will give an overview of the type of measurement technology used, the respective fields of application, and the selected parameters and their interpretation possibilities for each of the areas mentioned.

Effect of dual-tasking on walking and cognitive demands in adults with Alzheimer's dementia experienced in using a 4-wheeled walker

BACKGROUND

Learning to walk with a 4-wheeled walker increases cognitive demands in people with Alzheimer's dementia (AD). However, it is expected that experience will offset the increased cognitive demand. Current research has not yet evaluated gait in people with AD experienced in using a 4-wheeled walker under complex gait situations.

RESEARCH QUESTION

What is the effect of dual-task testing on the spatial-temporal gait parameters and cognitive performance of people with AD experienced with a 4-wheeled walker?

METHODS

Twenty-three adults with mild to moderate AD (87.4 ± 6.2 years, 48 % female) and at least 6 months of walker use experience participated. Three walking configurations: 1) straight path (SP), 2) Groningen Meander Walking Test (GMWT), and 3) Figure of 8 path (F8) were tested under two walking conditions: 1) single-task (walking with aid) and 2) dual-task (walking with aid and completing a cognitive task). Tri-axial accelerometers collected velocity, cadence and stride time variability (STV). Gait and cognitive task cost were the percentage difference between single-task and dual-task conditions. Two-way repeated measures ANOVAs were used to answer the study question.

RESULTS

A significant interaction between walking configuration and condition was found for velocity (p = 0.002, ω² = 0.36), cadence (p = 0.04, ω² = 0.15) and STV (p < 0.001, ω² = 0.53). Velocity and cadence decreased and STV increased with increasing walking configuration complexity and upon dual-tasking. Dual-task gait and cognitive task cost deteriorated in all walking configurations, but gait was prioritized in the GMWT and F8 configurations. Despite familiarity, experienced walker users with AD exhibit impaired gait when walking in complex situations which increases falls risk. Upon dual-task, individuals with AD self-prioritized a posture-first strategy in complex configurations.

SIGNIFICANCE

Dual-task testing in experienced users results in slower walking, fewer steps and increased STV, which increases falls risk in people with mild to moderate AD and becomes most pronounced in complex environments.

The impact of diabetic foot ulcers and unilateral offloading footwear on gait in people with diabetes

BACKGROUND

Unilateral offloading footwear prescribed to patients with diabetic foot ulcers elevates one limb relative to the other, which may lead to limp and abnormal gait. This study investigated whether the unilateral foot ulcer and offloading combination negatively impacts gait function beyond diabetic peripheral neuropathy.

METHODS

Eighty-six participants were recruited in 3 groups: 12 with diabetic peripheral neuropathy and unilateral foot ulcers wearing offloading footwear (offloading group, age = 55.6 ± 9.5 years, BMI = 30.9 ± 4.5 kg/m²), 27 with diabetic peripheral neuropathy (neuropathy group, age = 64.3 ± 7.7 years, BMI = 30.9 ± 5.4 kg/m²), and 47 non-diabetic controls (non-diabetic group, age = 62.9 ± 16.1 years, BMI = 29.0 ± 6.0 kg/m²). Gait function was quantified during a habitual speed walking test using a validated wearable platform.

FINDINGS

The offloading group exhibited deteriorated gait function compared to the non-diabetic group (p < 0.005, Cohen's effect size d = 0.90-2.61). They also had decreased gait speed (p < 0.001, d = 1.79) and stride length (p < 0.001, d = 1.76), as well as increased gait cycle time (p < 0.001, d = 1.67) and limp (p < 0.050, d = 0.72-1.49) compared to the neuropathy group. The offloading group showed increased gait unsteadiness compared to the neuropathy group, but the difference did not reach statistical significance in our samples.

INTERPRETATION

This study demonstrated that while diabetic peripheral neuropathy deteriorates gait function, including increasing gait unsteadiness and limp, the diabetic foot ulcer and offloading combination magnifies the deterioration beyond diabetic peripheral neuropathy. These findings promote caution of the current standards of care for treating diabetic foot ulcers with offloading footwear. However, it is possible that a contralateral shoe lift may remedy deteriorated gait function and improve quality of life for unilateral offloading users.

The top 100 most cited articles on total hip arthroplasty: a bibliometric analysis

BACKGROUND

Over the past few decades, more and more articles about total hip arthroplasty have been published. We noticed, however, little is known about the characteristics and qualities of these studies.

METHODS

The databases of Web of Science Core Collection, BIOSIS Citation Index, MEDLINE, etc. were utilized for the identification of articles published from 1990 to May 2019. Total hip arthroplasty-related articles were identified, and the 100 most cited articles were selected for subsequent analysis of citation count, citation density (citations/article age), authorship, theme, geographic distribution, time-related flux, level of evidence, and network analysis.

RESULTS

The selected 100 articles were published mainly in the 1990s (46%) and 2000s (47%) with almost equal amount. Citations per article ranged from 994 to 191. Leading countries were the USA followed by Canada, England, and Sweden, all located in North America and Western Europe. The most highlighted study themes were postoperative thrombosis and surgical methods and materials. The most common level of evidence was level III (35%). The network analysis connoted that radiography, acetabulum, reoperation, and bone cement had a high degree of centrality in the 1990s, while cement had a high degree of centrality in the 2000s and 2010s.

CONCLUSIONS

The time, area, and theme distribution of the top 100 most cited articles in the total hip arthroplasty have been thoroughly analyzed. It is noticeable that postoperative thromboembolism currently plays a major role in the field of total hip arthroplasty researches. However, most of them focus on the effectiveness of different treatments and drugs; little is known about its underlying mechanisms and influencing factors.

A Personalized Approach to Improve Walking Detection in Real-Life Settings: Application to Children with Cerebral Palsy

Although many methods have been developed to detect walking by using body-worn inertial sensors, their performances decline when gait patterns become abnormal, as seen in children with cerebral palsy (CP). The aim of this study was to evaluate if fine-tuning an existing walking bouts (WB) detection algorithm by various thresholds, customized at the individual or group level, could improve WB detection in children with CP and typical development (TD). Twenty children (10 CP, 10 TD) wore 4 inertial sensors on their lower limbs during laboratory and out-laboratory assessments. Features extracted from the gyroscope signals recorded in the laboratory were used to tune thresholds of an existing walking detection algorithm for each participant (individual-based personalization: Indiv) or for each group (population-based customization: Pop). Out-of-laboratory recordings were analyzed for WB detection with three versions of the algorithm (i.e., original fixed thresholds and adapted thresholds based on the Indiv and Pop methods), and the results were compared against video reference data. The clinical impact was assessed by quantifying the effect of WB detection error on the estimated walking speed distribution. The two customized Indiv and Pop methods both improved WB detection (higher, sensitivity, accuracy and precision), with the individual-based personalization showing the best results. Comparison of walking speed distribution obtained with the best of the two methods showed a significant difference for 8 out of 20 participants. The personalized Indiv method excluded non-walking activities that were initially wrongly interpreted as extremely slow walking with the initial method using fixed thresholds. Customized methods, particularly individual-based personalization, appear more efficient to detect WB in daily-life settings.

The association between motor capacity and mobility performance: frailty as a moderator

Background

In older adults, the linkage between laboratory-assessed ‘motor capacity’ and ‘mobility performance’ during daily routine is controversial. Understanding factors moderating this relationship could help developing more valid assessment as well as intervention approaches. We investigated whether the association between capacity and performance becomes evident with transition into frailty, that is, whether frailty status moderates their association.

Methods

We conducted a cross-sectional analysis of the observational (blinded for review) study in a community-dwelling cohort in (blinded for review). Participants were N = 112 older adults aged 65 years or older who were categorized as non-frail (n = 40), pre-frail (n = 53) or frail (n = 19) based on the Fried frailty index.

Motor capacity was quantified as normal (NWS) and fast walking speed (FWS). Mobility performance was quantified as 1) cumulated physical activity (PA) time and 2) everyday walking performance (average steps per walking bout; maximal number of steps in one walking bout), measured by a motion sensor over a 48 h period. Hierarchical linear regression analyses were performed to evaluate moderation effects.

Results

Unlike in non-frail persons, the relationship between motor capacity and mobility performance was evident in pre-frail and frail persons, confirming our hypothesis. A moderating effect of frailty status was found for 1) the relationship between both NWS and FWS and maximal number of steps in one bout and 2) NWS and the average steps per bout. No moderation was found for the association between NWS and FWS with cumulated PA.

Conclusion

In pre-frail and frail persons, motor capacity is associated with everyday walking performance, indicating that functional capacity seems to better represent mobility performance in this impaired population. The limited relationship found in non-frail persons suggests that other factors account for their mobility performance. Our findings may help to inform tailored assessment approaches and interventions taking into consideration a person’s frailty status.

Relationships between gait variability and ambulatory activity post stroke

BACKGROUND

Fall risk and balance confidence are related to gait variability and ambulatory activity post stroke, yet whether a relationship exists between gait variability and ambulatory activity is unknown. Knowing if gait variability measured under naturalistic conditions is related to ambulatory activity could explain more about the relationship between falls and walking activity post-stroke.

OBJECTIVES

To examine relationships between spontaneous, daily ambulatory activity and gait variability during single- and dual-task walking, in low- and high-distraction settings in adults post stroke.

METHODS

Sixteen community-dwelling adults post stroke participated in a cross-sectional study. Spatiotemporal gait parameters were recorded during single- and cognitive-motor dual-task walking in low- and high-distraction settings. Coefficient of variation was calculated for stride length and stride duration. Average walking bout duration, maximum walking bout duration, and total number of steps per day were captured using an activity monitor. Correlations between ambulatory activity measures and gait variability were examined.

RESULTS

In the high-distraction setting, single-task stride duration variability was negatively related to all three ambulatory activity measures, but the strongest relationship was a negative correlation between dual-task stride duration variability and average walking duration. In the low-distraction setting, single-task stride duration variability was negatively related to maximum walking duration. None of the other variability measures were related to ambulatory activity.

CONCLUSIONS

The finding that stride duration variability in a high-distraction environment, with or without an additional cognitive task, is related to ambulatory activity in community-dwelling stroke survivors suggests that assessments incorporating attentional demands of real-world walking may be useful additions to clinical practice.

Hemodialysis Impact on Motor Function beyond Aging and Diabetes-Objectively Assessing Gait and Balance by Wearable Technology

Motor functions are deteriorated by aging. Some conditions may magnify this deterioration. This study examined whether hemodialysis (HD) process would negatively impact gait and balance beyond diabetes condition among mid-age adults (48–64 years) and older adults (65+ years). One hundred and ninety-six subjects (age = 66.2 ± 9.1 years, body-mass-index = 30.1 ± 6.4 kg/m², female = 56%) in 5 groups were recruited: mid-age adults with diabetes undergoing HD (Mid-age HD+, n = 38) and without HD (Mid-age HD−, n = 40); older adults with diabetes undergoing HD (Older HD+, n = 36) and without HD (Older HD−, n = 37); and non-diabetic older adults (Older DM−, n = 45). Gait parameters (stride velocity, stride length, gait cycle time, and double support) and balance parameters (ankle, hip, and center of mass sways) were quantified using validated wearable platforms. Groups with diabetes had overall poorer gait and balance compared to the non-diabetic group (p < 0.050). Among people with diabetes, HD+ had significantly worsened gait and balance when comparing to HD− (Cohen’s effect size d = 0.63–2.32, p < 0.050). Between-group difference was more pronounced among older adults with the largest effect size observed for stride length (d = 2.32, p < 0.001). Results suggested that deterioration in normalized gait speed among HD+ was negatively correlated with age (r = −0.404, p < 0.001), while this correlation was diminished among HD−. Interestingly, results also suggested that poor gait among Older HD− is related to poor ankle stability, while no correlation was observed between poor ankle stability and poor gait among Older HD+. Using objective assessments, results confirmed that the presence of diabetes can deteriorate gait and balance, and this deterioration can be magnified by HD process. Among HD− people with diabetes, poor ankle stability described poor gait. However, among people with diabetes undergoing HD, age was a dominate factor describing poor gait irrespective of static balance. Results also suggested feasibility of using wearable platforms to quantify motor performance during routine dialysis clinic visit. These objective assessments may assist in identifying early deterioration in motor function, which in turn may promote timely intervention.

Sex specific associations between biomechanical recovery and clinical recovery after total hip arthroplasty

BACKGROUND

There are sex-specific gait differences in men and women before and after total hip arthroplasty (THA) but we do not know their impact on clinical outcomes. The objective of this study was to identify sex-specific associations between pre- and postoperative changes in pain and function and (i) gait mechanics, (ii) passive range of motion, and (iii) abductor strength.

METHODS

Pre- and one-year postoperative data were identified from a data repository (n = 124; 64 Women; Age 61 (SD 10); BMI 29 (SD 5)). We used linear regression analysis to identify sex-specific associations between Harris Hip Score pain and function subscores, and sagittal plane hip kinematics and 3D hip kinetics during gait, hip abductor strength, and passive hip range of motion (RoM).

FINDINGS

Combinations of biomechanical variables predicted up to 24% of the variation in pain improvement and up to 27% of the variation in functional improvement. In men, increased peak external rotation moments were associated with pain improvement. Passive flexion RoM and peak extension moments were associated with functional improvement. In women, increased passive adduction RoM and peak external rotation moments were associated with pain improvement. Peak adduction moments and passive flexion RoM were associated with functional improvement.

INTERPRETATIONS

The different associations between improvement in clinical outcomes and improvement in gait, passive RoM, and abductor strength suggest that the biomechanical path to recovery may be different in men and women.

Early clinical evaluation of total hip arthroplasty by three-dimensional gait analysis and muscle strength testing

BACKGROUND

As improvement of gait is an important reason for patients to undergo total hip arthroplasty (THA) and they generally tend to evaluate its success based on postoperative walking ability, objective functional evaluation of postoperative gait is important. However, the patient's normal gait before osteoarthritis is unknown and the changes that will occur postoperatively are unclear. We investigated the change in gait and hip joint muscle strength after THA by using a portable gait rhythmograph (PGR) and muscle strength measuring device.

PATIENT AND METHODS

The subjects were 46 women (mean age: 65.9 years) with osteoarthritis of the hip. Gait analysis and muscle strength testing were performed before THA, as well as 3 weeks and 3 months after surgery. We measured the walking speed, step length, and gait trajectory using PGR prospectively. PGR is attached to the patient's waist and records signals at a sampling rate of 100 Hz. Isometric torque of hip flexion and abduction were measured by using a hand-held dynamometer.

RESULTS

There was no improvement at 3 weeks postoperatively, but the walking speed, stride length and muscle strength were clearly showed improvement at 3 months postoperatively. The walking trajectory was not normal preoperatively, since the trajectory was not symmetrical and did not intersect in the midline or form a butterfly pattern, and abnormality of the trajectory tended to persist postoperative 3 months despite resolution of hip joint pain after surgery.

CONCLUSION

Since postoperative improvement of gait is an important consideration for patients undergoing THA, it seems relevant to evaluate changes in the gait after surgery and three-dimensional analysis with a PGR may be useful for this purpose.

Post-Fall Intelligence Supporting Fall Severity Diagnosis Using Kinect Sensor

This paper proposes a fall severity analytic and post-fall intelligence system with three interdependent modules. Module I is the analysis of fall severity based on factors extracted in the phases of during and after fall which include innovative measures of the sequence of body impact, level of impact, and duration of motionlessness. Module II is a timely autonomic notification to relevant persons with context-dependent fall severity alert via electronic communication channels (e.g., smartphone, tablet, or smart TV set). Lastly, Module III is the diagnostic support for caregivers and doctors to have information for making a well-informed decision of first aid or postcure with the chronologically traceable intelligence of information and knowledge found in Modules I and II. The system shall be beneficial to caregivers or doctors, in giving first aid/diagnosis/treatment to the subject, especially, in cases where the subject has lost consciousness and is unable to respond.

A practical step length algorithm using lower limb angular velocities

The use of Inertial Measurement Units (IMUs) for spatial gait analysis has opened the door to unconstrained measurements within the home and community. Bandwidth, cost limitations, and ease of use has historically restricted the number and location of sensors worn on the body. In this paper, we describe a four-sensor configuration of IMUs placed on the shanks and thighs that is sufficient to provide an accurate measure of temporal gait parameters, spatial gait parameters, and joint angle dynamics during ambulation. Estimating spatial gait parameters solely from gyroscope data is preferred because gyroscopes are less susceptible to sensor noise and a system comprised of only gyroscopes uses decreased bandwidth compared to a typical 9 degree-of-freedom IMU. The purpose of this study was to determine the validity of a novel method of step length estimation using gyroscopes attached to the shanks and thighs. An Inverted Pendulum Model algorithm (IPM) was proposed to calculate step length, stride length, and gait speed. The algorithm incorporates heel-strike events and average forward velocity per step to make these assessments. IMU algorithm accuracy was determined via concurrent validity with an instrumented walkway and results explained via the collision model of gait. The IPM produced accurate estimates of step length, stride length, and gait speed with a mean difference of 3 cm and an RMSE of 6.6 cm for step length, thus establishing a new approach for spatial gait parameter calculation. The lack of numerical integration in IPM makes it well suited for use in continuous monitoring applications where sensor sampling rates are restricted.

Total hip arthroplasty using a cementless dual-mobility cup provides increased stability and favorable gait parameters at five years follow-up

BACKGROUND

Rates of dislocation following primary total hip arthroplasty (THA) vary from 0.5 to 10%. Dual-mobility cups in THA demonstrate increased stability. Clinical outcomes following THA with dual-mobility cups have been reported, but gait has not been assessed. Therefore we performed a retrospective case control study to answer: (1) is gait better in patients following THA with a dual-mobility cup than in frail, elderly patients of the same age? (2) Are clinical outcomes better in patients following THA with a dual-mobility cup than in frail, elderly patients? (3) What is the dislocation rate following THA with a dual-mobility cup?

HYPOTHESIS

We hypothesized that patients who underwent THA with a dual-mobility cup have a better gait compared to frail, elderly patients of the same age.

PATIENTS AND METHODS

Twenty patients (22 hips), mean age 79.9±7.7 (range, 62.3-88.3) years were assessed in this retrospective case-control series 5.6±1.4 (range: 4.1-8.8) years following dual-mobility cup THA. A reference group consisted of 72 "frail elderly" patients in a rehabilitation hospital for health problems unrelated to the lower limb, with no lower limb surgery or neurological conditions. Temporal and spatial gait performance were measured with four miniature gyroscopes, mounted on each thigh and calf, while patients walked freely along a 30m corridor. Harris Hip Score, WOMAC, radiological outcomes, and dislocation rate were determined.

RESULTS

All gait parameters were better in the dual-mobility group compared to the frail elderly group. The dual-mobility group had a higher cadence (100.3 steps/minute versus 75.6 steps/minute), shorter (relative to gait cycle time) stance (61.6% versus 67.8%), shorter (relative to gait cycle time) double stance (23.3% versus 36.0%), longer stride (1.13m versus 0.80m), and faster walking speed (0.96m/s versus 0.52m/s). Range of motion of the shank, thigh and knee were better in the dual-mobility group. Harris Hip Score was 87.6±13.9 (range 51-100) and WOMAC score was 11.3±12.1 (range 0-34) in the THA group. We observed no dislocations.

DISCUSSION

Gait patterns five years following THA with the dual-mobility cup were better or comparable to published study populations.

LEVEL OF EVIDENCE

III, retrospective case-control series.

A Real-Time Gait Event Detection for Lower Limb Prosthesis Control and Evaluation

Lower extremity amputees suffer from mobility limitations which will result in a degradation of their quality of life. Wearable sensors are frequently used to assess spatio-temporal, kinematic and kinetic parameters providing the means to establish an interactive control of the amputee-prosthesis-environment system. Gait events and the gait phase detection of an amputee's locomotion are vital for controlling lower limb prosthetic devices. The paper presents an approach to real-time gait event detection for lower limb amputees using a wireless gyroscope attached to the shank when performing level ground and ramp activities. The results were validated using both healthy and amputee subjects and showed that the time differences in identifying Initial Contact (IC) and Toe Off (TO) events were larger in a transfemoral amputee when compared to the control subjects and a transtibial amputee (TTA). Overall, the time difference latency lies within a range of ±50 ms while the detection rate was 100% for all activities. Based on the validated results, the IC and TO events can be accurately detected using the proposed system in both control subjects and amputees when performing activities of daily living and can also be utilized in the clinical setup for rehabilitation and assessing the performance of lower limb prosthesis users.

Paravertebral spinal injection for the treatment of patients with degenerative facet osteoarthropathy: Evidence of motor performance improvements based on objective assessments

BACKGROUND

This study examined short- and long-term improvements in motor performance, quantified using wearable sensors, in response to facet spine injection in degenerative facet osteoarthropathy patients.

METHODS

Adults with confirmed degenerative facet osteoarthropathy were recruited and were treated with medial or intermediate branch block injection. Self-report pain, health condition, and disability (Oswestry), as well as objective motor performance measures (gait, balance, and timed-up-and-go) were obtained in five sessions: pre-surgery (baseline), immediately after the injection, one-month, three-month, and 12-month follow-ups. Baseline motor performance parameters were compared with 10 healthy controls.

FINDINGS

Thirty patients (age=50 (14) years) and 10 controls (age=46 (15) years) were recruited. All motor performance parameters were significantly different between groups. Results showed that average pain and Oswestry scores improved by 51% and 24%, respectively among patients, only one month after injection. Similarly, improvement in motor performance was most noticeable in one-month post-injection measurements; most improvements were observed in gait speed (14% normal walking, P<0.02), hip sway within balance tests (63% eyes-open P<0.01), and turning velocity within the timed-up-and-go test (28%, P<0.02). Better baseline motor performance led to better outcomes in terms of pain relief; baseline turning velocity was 18% faster among the responsive compared to the non-responsive patients.

INTERPRETATIONS

Spinal injection can temporarily (one to three months) improve motor performance in degenerative facet osteoarthropathy patients. Successful pain relief in response to treatment is independent of demographic characteristics and initial pain but dependent on baseline motor performance. Immediate self-reported pain relief is unrelated to magnitude of gradual improvement in motor performance.

Alterations in gait parameters with peripheral artery disease: The importance of pre-frailty as a confounding variable

Although poor walking is the most common symptom of peripheral artery disease (PAD), reported results are inconsistent when comparing gait parameters between PAD patients and healthy controls. This inconsistency may be due to frailty, which is highly prevalent among PAD patients. To address this hypothesis, 41 participants, 17 PAD (74±8 years) and 24 aged-matched controls (76±7 years), were recruited. Gait was objectively assessed using validated wearable sensors. Analysis of covariate (ANCOVA) tests were used to compare gait parameters between PAD and non-PAD groups, considering age, gender, and body mass index as covariates, while stratified based on frailty status. According to the Fried frailty index, 47% of PAD and 50% of control participants were non-frail and the rest were classified as pre-frail. Within non-frail participants, gait speed, body sway during walking, stride length, gait cycle time, double-support, knee range of motion, speed variability, mid-swing speed, and gait initiation were significantly different between PAD and control groups (effect size d = 0.75±0.43). In the pre-frail group, however, most of the gait differences were diminished except for gait initiation and gait variability. Results suggest that gait initiation is the most sensitive parameter for detecting gait impairment in PAD participants when compared to controls, regardless of frailty status (d = 1.30-1.41; p<0.050). The observed interaction effect between frailty and PAD on gait parameters confirms the importance of assessing functionality in addition to age to provide more consistency in detecting motor performance impairments due to PAD.

Gait analysis and WOMAC are complementary in assessing functional outcome in total hip replacement

Objective: To investigate the correlation between objective and subjective evaluation of patients with total hip replacement.

Design: Prospective preliminary trial comparing the Western Ontario and McMaster University questionnaire (WOMAC) and gait analysis preoperatively and three months postoperatively.

Setting: A German academic orthopaedic centre specializing in total hip replacement surgery.

Subjects: Seventeen patients (median age 70 years) with hip osteoarthritis.

Intervention: All patients had had a primary unilateral total hip replacement.

Main measures: WOMAC questionnaire to assess self-perceived health status and gait analysis to determine objective gait parameters.

Results: Performance of walking as well as subjective judgement of health status improved following surgery (gait speed P = 0.0222; stride length P = 0.038; stance phase ratio P = 0.0466; WOMAC P < 0.0001). However, the correlation between gait parameters and WOMAC was poor ( r = -0.27 or less). Correlation between changes of walking parameters and WOMAC was bad to good ( r = 0.01 to r = -0.72).

Conclusion: The WOMAC questionnaire might not reflect walking performance. The addition of gait analysis is recommended to gain objective information about the quality of gait.

Wearable inertial sensors for human movement analysis

INTRODUCTION

The present review aims to provide an overview of the most common uses of wearable inertial sensors in the field of clinical human movement analysis.

AREAS COVERED

Six main areas of application are analysed: gait analysis, stabilometry, instrumented clinical tests, upper body mobility assessment, daily-life activity monitoring and tremor assessment. Each area is analyzed both from a methodological and applicative point of view. The focus on the methodological approaches is meant to provide an idea of the computational complexity behind a variable/parameter/index of interest so that the reader is aware of the reliability of the approach. The focus on the application is meant to provide a practical guide for advising clinicians on how inertial sensors can help them in their clinical practice. Expert commentary: Less expensive and more easy to use than other systems used in human movement analysis, wearable sensors have evolved to the point that they can be considered ready for being part of routine clinical routine.

A Machine Learning Framework for Gait Classification Using Inertial Sensors: Application to Elderly, Post-Stroke and Huntington's Disease Patients

Machine learning methods have been widely used for gait assessment through the estimation of spatio-temporal parameters. As a further step, the objective of this work is to propose and validate a general probabilistic modeling approach for the classification of different pathological gaits. Specifically, the presented methodology was tested on gait data recorded on two pathological populations (Huntington’s disease and post-stroke subjects) and healthy elderly controls using data from inertial measurement units placed at shank and waist. By extracting features from group-specific Hidden Markov Models (HMMs) and signal information in time and frequency domain, a Support Vector Machines classifier (SVM) was designed and validated. The 90.5% of subjects was assigned to the right group after leave-one-subject–out cross validation and majority voting. The long-term goal we point to is the gait assessment in everyday life to early detect gait alterations.

Extraction of stride events from gait accelerometry during treadmill walking

Objective: evaluating stride events can be valuable for understanding the changes in walking due to aging and neurological diseases. However, creating the time series necessary for this analysis can be cumbersome. In particular, finding heel contact and toe-off events which define the gait cycles accurately are difficult. Method: we proposed a method to extract stride cycle events from tri-axial accelerometry signals. We validated our method via data collected from 14 healthy controls, 10 participants with Parkinson’s disease, and 11 participants with peripheral neuropathy. All participants walked at self-selected comfortable and reduced speeds on a computer-controlled treadmill. Gait accelerometry signals were captured via a tri-axial accelerometer positioned over the L3 segment of the lumbar spine. Motion capture data were also collected and served as the comparison method. Results: our analysis of the accelerometry data showed that the proposed methodology was able to accurately extract heel and toe-contact events from both feet. We used t-tests, analysis of variance (ANOVA) and mixed models to summarize results and make comparisons. Mean gait cycle intervals were the same as those derived from motion capture, and cycle-to-cycle variability measures were within 1.5%. Subject group differences could be similarly identified using measures with the two methods. Conclusions: a simple tri-axial acceleromter accompanied by a signal processing algorithm can be used to capture stride events. Clinical impact: the proposed algorithm enables the assessment of stride events during treadmill walking, and is the first step toward the assessment of stride events using tri-axial accelerometers in real-life settings.

Improvement of walking speed and gait symmetry in older patients after hip arthroplasty: a prospective cohort study

Background

Retraining walking in patients after hip or knee arthroplasty is an important component of rehabilitation especially in older persons whose social interactions are influenced by their level of mobility. The objective of this study was to test the effect of an intensive inpatient rehabilitation program on walking speed and gait symmetry in patients after hip arthroplasty (THA) using inertial sensor technology.

Methods

Twenty-nine patients undergoing a 4-week inpatient rehabilitation program following THA and 30 age-matched healthy subjects participated in this study. Walking speed and gait symmetry parameters were measured using inertial sensor device for standardized walking trials (2*20.3 m in a gym) at their self-selected normal and fast walking speeds on postoperative days 15, 21, and 27 in patients and in a single session in control subjects. Walking speed was measured using timing lights. Gait symmetry was determined using autocorrelation calculation of the cranio-caudal (CC) acceleration signals from an inertial sensor placed at the lower spine.

Results

Walking speed and gait symmetry improved from postoperative days 15–27 (speed, female: 3.2 and 4.5 m/s; male: 4.2 and 5.2 m/s; autocorrelation, female: 0.77 and 0.81; male: 0.70 and 0.79; P <0.001 for all). After the 4-week rehabilitation program, walking speed and gait symmetry were still lower than those in control subjects (speed, female 4.5 m/s vs. 5.7 m/s; male: 5.2 m/s vs. 5.3 m/s; autocorrelation, female: 0.81 vs. 0.88; male: 0.79 vs. 0.90; P <0.001 for all).

Conclusions

While patients with THA improved their walking capacity during a 4-week inpatient rehabilitation program, subsequent intensive gait training is warranted for achieving normal gait symmetry. Inertial sensor technology may be a useful tool for evaluating the rehabilitation process during the post-inpatient period.

How Angular Velocity Features and Different Gyroscope Noise Types Interact and Determine Orientation Estimation Accuracy

In human movement analysis, 3D body segment orientation can be obtained through the numerical integration of gyroscope signals. These signals, however, are affected by errors that, for the case of micro-electro-mechanical systems, are mainly due to: constant bias, scale factor, white noise, and bias instability. The aim of this study is to assess how the orientation estimation accuracy is affected by each of these disturbances, and whether it is influenced by the angular velocity magnitude and 3D distribution across the gyroscope axes. Reference angular velocity signals, either constant or representative of human walking, were corrupted with each of the four noise types within a simulation framework. The magnitude of the angular velocity affected the error in the orientation estimation due to each noise type, except for the white noise. Additionally, the error caused by the constant bias was also influenced by the angular velocity 3D distribution. As the orientation error depends not only on the noise itself but also on the signal it is applied to, different sensor placements could enhance or mitigate the error due to each disturbance, and special attention must be paid in providing and interpreting measures of accuracy for orientation estimation algorithms.

Validation and User Evaluation of a Sensor-Based Method for Detecting Mobility-Related Activities in Older Adults

Regular physical activity is essential for older adults to stay healthy and independent. However, daily physical activity is generally low among older adults and mainly consists of activities such as standing and shuffling around indoors. Accurate measurement of this low-energy expenditure daily physical activity is crucial for stimulation of activity. The objective of this study was to assess the validity of a necklace-worn sensor-based method for detecting time-on-legs and daily life mobility related postures in older adults. In addition user opinion about the practical use of the sensor was evaluated. Twenty frail and non-frail older adults performed a standardized and free movement protocol in their own home. Results of the sensor-based method were compared to video observation. Sensitivity, specificity and overall agreement of sensor outcomes compared to video observation were calculated. Mobility was assessed based on time-on-legs. Further assessment included the categories standing, sitting, walking and lying. Time-on-legs based sensitivity, specificity and percentage agreement were good to excellent and comparable to laboratory outcomes in other studies. Category-based sensitivity, specificity and overall agreement were moderate to excellent. The necklace-worn sensor is considered an acceptable valid instrument for assessing home-based physical activity based upon time-on-legs in frail and non-frail older adults, but category-based assessment of gait and postures could be further developed.

Validation of a smartphone-based measurement tool for the quantification of level walking

INTRODUCTION

It is important to assess and quantify gait in order to determine the severity of impairments during gait and to evaluate therapeutic interventions. However, laboratory gait assessment is expensive and time consuming and there is a lack of an easily applicable tool for the quantification of gait in clinical practice. The aim of this study was to validate a smartphone-based measurement tool for the quantification of level walking.

METHODS

Vertical center of mass displacement and step duration of 22 healthy young adults were assessed by a smartphone application and a motion capture system. Intra-session reliability was evaluated by repeated-measures ANOVA, intraclass correlation coefficient (ICC), and standard error of measurement. In order to evaluate the concurrent validity of the smartphone application, smartphone- and motion capture-derived values were compared by Pearson correlation coefficient and Bland-Altman limits of agreement.

RESULTS

Six out of eight variables derived by the smartphone application showed an excellent reliability (ICC≥0.75) and all variables correlated significantly with measurements of the motion capture system with moderate to strong correlations ranging from 0.61 to 0.92.

CONCLUSION

The results showed a great potential of the smartphone application to be a user-friendly and valid tool for the assessment of gait in clinical practice. Further research needs to investigate whether the smartphone application is able to detect differences in gait patterns following therapeutic or orthopedic interventions and whether it is valid for the quantification of gait in people with movement disorders.

Gait phase detection in able-bodied subjects and dementia patients

Accurate detection of gait phases allows identification of specific functional deficits at each phase of the gait cycle for motor function assessment. This paper proposes a robust gait phase detection method to identify the seven gait phases in overground walking for normal and pathologic gaits. Four inertial sensors are used to obtain knee angles, tibia angles and feet angular rate patterns in the sagittal plane. The key events segmenting the gait cycles are searched using an adaptive threshold in adaptive searching intervals to make sure it works well for different subjects with high variation in cadence and step length during walking. The subjects involved in this study are categorized into three groups: five healthy adult subjects, two healthy elderly subjects and two severe dementia patients. The experimental results have shown our method can reliably detect all gait phases for able-bodied subjects and dementia patients without subject-specific calibration.

A Mobile Kalman-Filter Based Solution for the Real-Time Estimation of Spatio-Temporal Gait Parameters

Gait impairments are among the most disabling symptoms in several musculoskeletal and neurological conditions, severely limiting personal autonomy. Wearable gait sensors have been attracting attention as diagnostic tool for gait and are emerging as promising tool for tutoring and guiding gait execution. If their popularity is continuously growing, still there is room for improvement, especially towards more accurate solutions for spatio-temporal gait parameters estimation. We present an implementation of a zero-velocity-update gait analysis system based on a Kalman filter and off-the-shelf shoe-worn inertial sensors. The algorithms for gait events and step length estimation were specifically designed to comply with pathological gait patterns. More so, an Android app was deployed to support fully wearable and stand-alone real-time gait analysis. Twelve healthy subjects were enrolled to preliminarily tune the algorithms; afterwards sixteen persons with Parkinson's disease were enrolled for a validation study. Over the 1314 strides collected on patients at three different speeds, the total root mean square difference on step length estimation between this system and a gold standard was 2.9%. This shows that the proposed method allows for an accurate gait analysis and paves the way to a new generation of mobile devices usable anywhere for monitoring and intervention.

A randomized controlled trial of custom foot orthoses for the treatment of plantar heel pain

BACKGROUND

Up to 10% of people will experience heel pain. The purpose of this prospective, double-blind, randomized clinical trial was to compare custom foot orthoses (CFO), prefabricated foot orthoses (PFO), and sham insole treatment for plantar fasciitis.

METHODS

Seventy-seven patients with plantar fasciitis for less than 1 year were included. Outcome measures included first step and end of day pain, Revised Foot Function Index short form (FFI-R), 36-Item Short Form Health Survey (SF-36), activity monitoring, balance, and gait analysis.

RESULTS

The CFO group had significantly improved total FFI-R scores (77.4 versus 57.2; P = .03) without group differences for FFI-R pain, SF-36, and morning or evening pain. The PFO and CFO groups reported significantly lower morning and evening pain. For activity, the CFO group demonstrated significantly longer episodes of walking over the sham (P = .019) and PFO (P = .03) groups, with a 125% increase for CFOs, 22% PFOs, and 0.2% sham. Postural transition duration (P = .02) and balance (P = .05) improved for the CFO group. There were no gait differences. The CFO group reported significantly less stretching and ice use at 3 months.

CONCLUSIONS

The CFO group demonstrated 5.6-fold greater improvements in spontaneous physical activity versus the PFO and sham groups. All three groups improved in morning pain after treatment that included standardized athletic shoes, stretching, and ice. The CFO changes may have been moderated by decreased stretching and ice use after 3 months. These findings suggest that more objective measures, such as spontaneous physical activity improvement, may be more sensitive and specific for detecting improved weightbearing function than traditional clinical outcome measures, such as pain and disease-specific quality of life.

Online decoding of hidden Markov models for gait event detection using foot-mounted gyroscopes

In this paper, we present an approach to the online implementation of a gait event detector based on machine learning algorithms. Gait events were detected using a uniaxial gyro that measured the foot instep angular velocity in the sagittal plane to feed a four-state left-right hidden Markov model (HMM). The short-time Viterbi algorithm was used to overcome the limitation of the standard Viterbi algorithm, which does not allow the online decoding of hidden state sequences. Supervised learning of the HMM structure and validation with the leave-one-subject-out validation method were performed using treadmill gait reference data from an optical motion capture system. The four gait events were foot strike, flat foot (FF), heel off (HO), and toe off. The accuracy ranged, on average, from 45 ms (early detection, FF) to 35 ms (late detection, HO); the latency of detection was less than 100 ms for all gait events but the HO, where the probability that it was greater than 100 ms was 25%. Overground walking tests of the HMM-based gait event detector were also successfully performed.

BioKin: an ambulatory platform for gait kinematic and feature assessment

A platform to move gait analysis, which is normally restricted to a clinical environment in a well-equipped gait laboratory, into an ambulatory system, potentially in non-clinical settings is introduced. This novel system can provide functional measurements to guide therapeutic interventions for people requiring rehabilitation with limited access to such gait laboratories. BioKin system consists of three layers: a low-cost wearable wireless motion capture sensor, data collection and storage engine, and the motion analysis and visualisation platform. Moreover, a novel limb orientation estimation algorithm is implemented in the motion analysis platform. The performance of the orientation estimation algorithm is validated against the orientation results from a commercial optical motion analysis system and an instrumented treadmill. The study results demonstrate a root-mean-square error less than 4° and a correlation coefficient more than 0.95 when compared with the industry standard system. These results indicate that the proposed motion analysis platform is a potential addition to existing gait laboratories in order to facilitate gait analysis in remote locations.

Texting and walking: effect of environmental setting and task prioritization on dual-task interference in healthy young adults

Recent studies have shown that young adults significantly reduce their gait speed and weave more when texting while walking. Previous research has not examined the simultaneous dual-task effects on texting performance, therefore, the attention prioritization strategy used by young adults while texting and walking is not currently known. Moreover, it is not known whether laboratory-based studies accurately reflect texting and walking performance in the real world. This study compared dual-task interference during texting and walking between laboratory and real-world settings, and examined the ability of young adults to flexibly prioritize their attention between the two tasks in each environment. Texting and walking were assessed in single-task and three dual-task conditions (no-priority, gait-priority, texting-priority) in the lab and a University Student Center, in 32 healthy young adults. Dual-task effects on gait speed, texting speed, and texting accuracy were significant, but did not significantly differ between the two environments. Young adults were able to flexibly prioritize their attention between texting and walking, according to specific instruction, and this ability was not influenced by environmental setting. In the absence of instructions, young adults prioritized the texting task in the low-distraction environment, but displayed more equal focus between tasks in the real world. The finding that young adults do not significantly modify their texting and walking behavior in high-distraction environments lends weight to growing concerns about cell phone use and pedestrian safety.

PERFORM: a system for monitoring, assessment and management of patients with Parkinson's disease

In this paper, we describe the PERFORM system for the continuous remote monitoring and management of Parkinson's disease (PD) patients. The PERFORM system is an intelligent closed-loop system that seamlessly integrates a wide range of wearable sensors constantly monitoring several motor signals of the PD patients. Data acquired are pre-processed by advanced knowledge processing methods, integrated by fusion algorithms to allow health professionals to remotely monitor the overall status of the patients, adjust medication schedules and personalize treatment. The information collected by the sensors (accelerometers and gyroscopes) is processed by several classifiers. As a result, it is possible to evaluate and quantify the PD motor symptoms related to end of dose deterioration (tremor, bradykinesia, freezing of gait (FoG)) as well as those related to over-dose concentration (Levodopa-induced dyskinesia (LID)). Based on this information, together with information derived from tests performed with a virtual reality glove and information about the medication and food intake, a patient specific profile can be built. In addition, the patient specific profile with his evaluation during the last week and last month, is compared to understand whether his status is stable, improving or worsening. Based on that, the system analyses whether a medication change is needed—always under medical supervision—and in this case, information about the medication change proposal is sent to the patient. The performance of the system has been evaluated in real life conditions, the accuracy and acceptability of the system by the PD patients and healthcare professionals has been tested, and a comparison with the standard routine clinical evaluation done by the PD patients' physician has been carried out. The PERFORM system is used by the PD patients and in a simple and safe non-invasive way for long-term record of their motor status, thus offering to the clinician a precise, long-term and objective view of patient's motor status and drug/food intake. Thus, with the PERFORM system the clinician can remotely receive precise information for the PD patient's status on previous days and define the optimal therapeutical treatment.

Estimation of step-by-step spatio-temporal parameters of normal and impaired gait using shank-mounted magneto-inertial sensors: application to elderly, hemiparetic, parkinsonian and choreic gait

BACKGROUND

The step-by-step determination of the spatio-temporal parameters of gait is clinically relevant since it provides an estimation of the variability of specific gait patterns associated with frequent geriatric syndromes. In recent years, several methods, based on the use of magneto-inertial units (MIMUs), have been developed for the step-by-step estimation of the gait temporal parameters. However, most of them were applied to the gait of healthy subjects and/or of a single pathologic population. Moreover, spatial parameters in pathologic populations have been rarely estimated step-by-step using MIMUs. The validity of clinically suitable MIMU-based methods for the estimation of spatio-temporal parameters is therefore still an open issue. The aim of this study was to propose and validate a method for the determination of both temporal and spatial parameters that could be applied to normal and heavily compromised gait patterns.

METHODS

Two MIMUs were attached above each subject's ankles. An instrumented gait mat was used as gold standard. Gait data were acquired from ten hemiparetic subjects, ten choreic subjects, ten subjects with Parkinson's disease and ten healthy older adults walking at two different gait speeds. The method detects gait events (GEs) taking advantage of the cyclic nature of gait and exploiting some lower limb invariant kinematic characteristics. A combination of a MIMU axes realignment along the direction of progression and of an optimally filtered direct and reverse integration is used to determine the stride length.

RESULTS

Over the 4,514 gait cycles analyzed, neither missed nor extra GEs were generated. The errors in identifying both initial and final contact at comfortable speed ranged between 0 and 11 ms for the different groups analyzed. The stride length was estimated for all subjects with less than 3% error.

CONCLUSIONS

The proposed method is apparently extremely robust since gait speed did not substantially affect its performance and both missed and extra GEs were avoided. The spatio-temporal parameters estimates showed smaller errors than those reported in previous studies and a similar level of precision and accuracy for both healthy and pathologic gait patterns. The combination of robustness, precision and accuracy suggests that the proposed method is suitable for routine clinical use.

Are Harris hip scores and gait mechanics related before and after THA?

BACKGROUND

Discordance between subjective and objective functional measures hinders the development of new ways to improve THA outcomes.

QUESTIONS/PURPOSES

We asked if (1) any kinematic or kinetic gait variables are correlated with preoperative Harris hip scores (HHS), (2) any kinematic or kinetic gait variables are correlated with postoperative HHS, and (3) pre- to postoperative changes in any kinematic or kinetic gait variables are associated with the change in HHS?

METHODS

For this retrospective study, an institutional review board-approved data repository that included all individuals who participated in motion analysis research studies was used to identify subjects evaluated before (n=161) and at least 6 months after primary unilateral THA (n=156). Selected kinematic (sagittal plane dynamic hip ROM and kinetic (peak external moments about the hip in the sagittal, frontal, and transverse planes) gait variables were collected at subjects' self-selected normal walking speeds. We used first-order partial correlations to identify relationships between HHS and gait variables, controlling for the influence of speed.

RESULTS

Preoperative HHS correlated with hip ROM (R|speed=0.260; p<0.001) and the peak extension moment (R|speed=0.164; p=0.038), postoperative HHS correlated with the peak internal rotation moment (R|speed=0.178; p=0.034), and change in HHS correlated with change in hip ROM (R|speed=0.288; p=0.001) and peak external rotation moment (R|speed=0.291; p=0.002). Similar associations were seen when the HHS pain and function were analyzed separately.

CONCLUSIONS

This study identified relationships between a common clinical outcome measure and specific, modifiable gait adaptations that can persist after THA-ROM and transverse plane gait moments. Addressing these aspects of gait dysfunction through focused rehabilitation could be a new strategy for improving clinical outcomes. Prospective studies are needed to evaluate this concept.

LEVEL OF EVIDENCE

Level III, diagnostic study. See the Instructions for Authors for a complete description of levels of evidence.