Evaluation of an inertial sensor system for analysis of timed-up-and-go under dual-task demands

Towards a Comprehensive Framework for Complex Walking tasks: Characterization, Behavioral Adaptations, and Clinical Implications in Ageing and Neurological Populations

Complex walking tasks, including change of direction, patterns and rhythms, require more attentional resources than simple walking and significantly impact walking performance, especially among ageing and neurological populations. More studies are focusing on complex walking situations, with or without the addition of cognitive tasks, creating a multitude of walking situations. Facing the lack of a clear and extensive definition of complex walking, this narrative review aims to identify and more precisely characterize situations and related tests, gain a better understanding of the behavioral adaptations in ageing and neurological populations, and report the clinical applications of complex walking. Based on the studies gathered, we propose a framework that categorizes the different forms of complex walking, considering whether a cognitive task is added or not, as well as the number of distinct objectives within the situation. We observed that combining complex walking tasks with a cognitive assignment places even greater strain on attentional resources, resulting in a more pronounced decline in walking or cognitive performance, or both. This work highlights the relevance of the complex walking as a simple tool for the early detection of cognitive impairments and the risk of falls, and its potential value in cognitive-motor rehabilitation. Future studies should explore the diversity of complex walking tasks in real-life simulated through extended virtual environments.

Assessment of Mobility Trajectories Using Wearable Inertial Sensors During Autologous Hematopoietic Cell Transplant

OBJECTIVE

This study aimed to characterize mobility patterns using wearable inertial sensors and serial assessment across autologous hematopoietic cell transplant (autoHCT) and investigate the relation between mobility and perceived function in patients with hematologic cancer.

DESIGN

Prospective longitudinal study.

SETTING

Hospital adult transplant clinic followed by discharge.

PARTICIPANTS

78 patients with hematological cancer receiving autoHCT.

MAIN OUTCOME MEASURES

Mobility was measured across 3 clinical phases (pretransplant, pre-engraftment, and post-engraftment) in using inertial sensors worn during prescribed performance tests in the hospital. Perceived function was assessed using validated provider-reported (Eastern Cooperative Oncology Group [ECOG] Performance Status Scale) and patient-reported [European Organization for Research and Treatment of Cancer Quality of Life Questionnaire [EORTC QLQ-C30]) measures. Trajectories of 5 selected mobility characteristics (turn duration, gait speed, stride time variability, double support time, and heel strike angle) across the clinical phases were also evaluated using piecewise linear mixed-effects models.

RESULTS

Using Principal Components Analysis, 4 mobility patterns were identified pretransplant: Gait Limitation, Sagittal Sway, Coronal Sway, and Balance Control. Gait Limitation measured pretransplant was significantly inversely associated with perceived function reported by the provider- (β = -0.11; 95% CI: -0.19, -0.02) and patient- (β = -4.85; 95% CI: -7.72, -1.99) post-engraftment in age-adjusted linear regression models. Mobility characteristics demonstrated immediate declines early pre-engraftment with stabilization by late pre-engraftment.

CONCLUSION

Patients with hematological cancer experiencing gait limitations pretransplant are likely to have worse perceived function post-engraftment. Mobility declines in early phases post-transplant and may not fully recover, indicating an opportunity for timely rehabilitation referrals. Wearable inertial sensors can be used to identify early mobility problems and patients who may be at risk for future functional decline who may be candidates for early physical rehabilitation.

Effects of a multicomponent physical activity programme, Mobility-Fit, compared with a standard care lower limb strengthening programme, to promote safe mobility among older adults in care facilities: protocol for a cluster randomised controlled trial

INTRODUCTION

Upper limb and core strength training is essential for older adults to safely perform daily activities. However, existing exercise programmes mainly focus on lower limb strength and are not designed or delivered to suit people with different functional capacities. This study describes the design of a two-arm cluster randomised controlled trial to examine the effects of a multicomponent physical activity (PA) programme, Mobility-Fit, on mobility and frailty in older adults living in care facilities.

METHODS AND ANALYSIS

160 older adults from 20 care facilities in Hong Kong will be recruited and randomised by care facilities (1:1) to an intervention or a control group. Participants in the intervention group will attend the Mobility-Fit programme, led by facility-based instructors, three times per week, 45 min per session, for 12 weeks, while the control group will participate in a standard care lower limb strengthening programme offered by the care facility. Participants will then be followed up for 9 months. Mobility-Fit comprises agility, postural coordination, balance and strength training, with suitable dosage based on participant's baseline physical and cognitive function. The primary outcomes encompass upper and lower limb strength, trunk stability, reaction time, mobility function and fall efficacy. Secondary outcomes comprise daily PA level and performance, frailty, cognitive function and quality of life. A repeated measures analysis of variance (ANOVA) and generalised estimating equation (GEE) will be used to examine changes in outcomes over time and between groups. Data will be analysed following the intention-to-treat principles. We will also evaluate programme implementation and health economics throughout the follow-up period.

ETHICS AND DISSEMINATION

Ethical approval was acquired in November 2022 from the Joint CUHK-NTEC Clinical Research Ethics Committee in Hong Kong (CREC-2022-459). Informed consent will be obtained from participants. The results of the study will be disseminated through peer-reviewed articles, conference presentations and social media.

TRIAL REGISTRATION NUMBER

ChiCTR2300072709.

Dual-tasking interference is exacerbated outdoors: A pilot study

Introduction

Walking while texting can create gait disturbances that may increase fall risk, especially in outdoors environment. To date, no study has quantified the effect of texting on motor behavior using different dynamic tasks in outdoor environments. We aimed to explore the impact of texting on dynamic tasks in indoor and outdoor environments.

Methods

Twenty participants (age 38.3 ± 12.5 years, 12 F) had a Delsys inertial sensor fixed on their back and completed walk, turn, sit-to-stand, and stand-to-sit subtasks with and without texting in both indoor and outdoor environments.

Results

While there was no difference in texting accuracy (p = 0.3), there was a higher dual-tasking cost in walking time with texting outdoors than indoors (p = 0.008).

Discussion

Dual tasking has a greater impact on walking time outdoors compared to an indoor environment. Our findings highlight the importance of patient education concerning dual-tasking and pedestrian safety in clinical settings.

Evaluation of Lower-Limb Kinematics during Timed Up and Go (TUG) Test in Subjects with Locomotive Syndrome (LS) Using Wearable Gait Sensors (H-Gait System)

Few studies have dealt with lower-limb kinematics during the timed up and go (TUG) test in subjects with locomotive syndrome (LS). This study aimed to evaluate the characteristics of lower-limb kinematics during the TUG test in subjects with LS using the wearable sensor-based H-Gait system. A total of 140 participants were divided into the non-LS (n = 28), the LS-stage 1 (n = 78), and LS-stage 2 (n = 34) groups based on the LS risk test. Compared with the non-LS group, the LS-stage 1 and LS-stage 2 groups showed significantly smaller angular velocity of hip and knee extension during the sit-to-stand phase. The LS-stage 2 group showed significantly smaller peak angles of hip extension and flexion during the walking-out phase compared to the non-LS group. These findings indicate that the evaluation of the lower-limb kinematics during the TUG test using the H-Gait system is highly sensitive to detect LS, compared with the evaluation of the lower-limb kinematics when simply walking.

Using Wearable Inertial Sensors to Assess Mobility of Patients With Hematologic Cancer and Associations With Chemotherapy-Related Symptoms Before Autologous Hematopoietic Stem Cell Transplant: Cross-sectional Study

BACKGROUND

Wearable sensors could be a simple way to quantify and characterize mobility in patients with hematologic cancer scheduled to receive autologous hematopoietic stem cell transplant (autoHSCT) and how they may be related to common treatment-related symptoms and side effects of induction chemotherapy.

OBJECTIVE

We aimed to conduct a cross-sectional study comparing mobility in patients scheduled to receive autoHSCT with that in healthy, age-matched adult controls and determine the relationships between patient mobility and chemotherapy-related symptoms.

METHODS

Patients scheduled to receive autoHSCT (78/156, 50%) and controls (78/156, 50%) completed the prescribed performance tests using wearable inertial sensors to quantify mobility including turning (turn duration and number of steps), gait (gait speed, stride time, stride time variability, double support time, coronal trunk range of motion, heel strike angle, and distance traveled), and balance (coronal sway, coronal range, coronal velocity, coronal centroidal frequency, sagittal sway, sagittal range, sagittal velocity, and sagittal centroidal frequency). Patients completed the validated patient-reported questionnaires to assess symptoms common to chemotherapy: chemotherapy-induced peripheral neuropathy (Functional Assessment of Cancer Therapy/Gynecologic Oncology Group-Neurotoxicity subscale), nausea and pain (European Organization for Research and Treatment of Cancer Quality of Life Questionnaire), fatigue (Patient-Reported Outcomes Measurement Information System Fatigue Short Form 8a), vertigo (Vertigo Symptom Scale-short form), and depression (Center for Epidemiological Studies-Depression). Paired, 2-sided t tests were used to compare mobility between patients and controls. Stepwise multivariable linear regression models were used to evaluate associations between patient mobility and symptoms.

RESULTS

Patients aged 60.3 (SD 10.3) years had significantly worse turning (turn duration; P<.001), gait (gait speed, stride time, stride time variability, double support time, heel strike angle, stride length, and distance traveled; all P<.001), and balance (coronal sway; P<.001, range; P<.001, velocity; P=.02, and frequency; P=.02; and sagittal range; P=.008) than controls. In patients, high nausea was associated with worse stride time variability (ß=.001; P=.005) and heel strike angle (ß=-.088; P=.02). Pain was associated with worse gait speed (ß=-.003; P=.003), stride time variability (ß=.012; P=.02), stride length (ß=-.002; P=.004), and distance traveled (ß=-.786; P=.005). Nausea and pain explained 17% to 33% and 14% to 36% of gait variance measured in patients, respectively.

CONCLUSIONS

Patients scheduled to receive autoHSCT demonstrated worse mobility in multiple turning, gait, and balance domains compared with controls, potentially related in part to nausea and pain. Wearable inertial sensors used in the clinic setting could provide granular information about mobility before further treatment, which may in turn benefit from rehabilitation or symptom management. Future longitudinal studies are needed to better understand temporal changes in mobility and symptoms across the treatment trajectory to optimally time, design, and implement strategies, to preserve functioning in patients with hematologic cancer in the long term.

Dividing attention during the Timed Up and Go enhances associations of several subtask performances with MCI and cognition

We tested the hypothesis that dividing attention would strengthen the ability to detect mild cognitive impairment (MCI) and specific cognitive abilities from Timed Up and Go (TUG) performance in the community setting. While wearing a belt-worn sensor, 757 dementia-free older adults completed TUG during two conditions, with and without a concurrent verbal serial subtraction task. We segmented TUG into its four subtasks (i.e., walking, turning, and two postural transitions), and extracted 18 measures that were summarized into nine validated sensor metrics. Participants also underwent a detailed cognitive assessment during the same visit. We then employed a series of regression models to determine the combinations of subtask sensor metrics most strongly associated with MCI and specific cognitive abilities for each condition. We also compared subtask performances with and without dividing attention to determine whether the costs of divided attention were associated with cognition. While slower TUG walking and turning were associated with higher odds of MCI under normal conditions, these and other subtask associations became more strongly linked to MCI when TUG was performed under divided attention. Walking and turns were also most strongly associated with executive function and attention, particularly under divided attention. These differential associations with cognition were mirrored by performance costs. However, since several TUG subtasks were more strongly associated with MCI and cognitive abilities when performed under divided attention, future work is needed to determine how instrumented dual-task TUG testing can more accurately estimate risk for late-life cognitive impairment in older adults.

Temporal Variation Quantification During Cognitive Dual-Task Gait Using Two IMU Sensors

Multiple tasks are simultaneously performed during walking in our daily life. Distracted walk by smartphone usage is recently getting a social problem. The term dual-task gait refers to the secondary task added to the walking. Attention demanding tasks may influence how a person walks. Since in-lab measurement may not accurately reflect the daily living gait, wearable sensors approach have been proposed for gait analysis in an out-of-lab setting. This study addresses the potential of using only two inertial measurement units (IMUs) attached to the shoes for the assessment of cognitive dual-task gait and how it differs from single-task gait. We found that the proposed system is sensitive to recognizing a tiny change in gait features such as on the double support time and gait indices when subject performing dual-task gait compared to the single-task gait experiment.

The effect of different dual tasks conditions on gait kinematics and spatio-temporal walking parameters in older adults

BACKGROUND

Dual-task (DT) walking has increasingly been investigated over the last decade because of its valuable role as a clinical marker of both cognitive impairment and fall risk in older adults based on cognitive and motor performance (DTEcog, DTEmotor). However, there is still a lack of information on what type of dual task to choose and which is the most adapted to the population of interest.

RESEARCH QUESTION

To evaluate the effect of different dual-tasks (DT3, DT7, FLU, STROOP) on the spatiotemporal and kinematic parameters of hip, knee, and ankle joints.

METHODS

Thirty-eight older adults were recruited (9 men, 29 women, mean age = 77.5 +/- 6.5 years, mean height = 163.6 +/- 8.6 cm, mean weight = 67.5 +/- 15.3 kg). They performed a single and dual-task walk with the 4 types of tasks during 1 min, equipped with an inertial system. Dual-task effect (DTE) on spatiotemporal and kinematic variables as well as cognitive score and speed were calculated.

RESULTS

An alteration in most of the spatiotemporal parameters was observed in each DT condition (p < 0.05), especially in arithmetic tasks (DT3, DT7), while no DT effect was noticed on kinematic parameters (RMSE<3°) except on hip and knee angular velocities (RMSE>15°). Arithmetic tasks seemed to alter more spatiotemporal and kinematic parameters than the verbal fluency or STROOP test. However, DT7 appeared to be too difficult for the population of interest.

SIGNIFICANCE

Arithmetic tasks seemed to be very pertinent as a clinical dual-task protocol for older adults. The use of an inertial system to retrieve kinematic variables is an improvement in these dual-task protocols.

Assessment of dual-tasking during a dynamic balance task using a smartphone app: a pilot study

[Purpose] To assess if the instrumented Timed Up and Go (iTUG) task score calculated with an iPhone application can detect gait changes under dual-tasking conditions. [Participants and Methods] Twenty participants (age 38.30 ± 12.54, 12 females) were asked to complete the TUG as a single task and under two dual-tasking conditions: 1) verbal fluency and 2) mental calculation. We used a smartphone, stopwatch, digital camera, and wearable sensor to calculate the dependent variables which included time, step count, gait speed, and iTUG score and, the dual-tasking cost (DTC) of those variables. We used Friedman analyses of variance and Wilcoxon tests for statistical analyses. [Results] the iTUG score, step count, gait speed, and the time measured by the stopwatch and wearable sensor differed significantly for all tasks, but the smartphone time did not. [Conclusion] We conclude that the iTUG score could be used as a sensitive measure for identifying gait changes under dual-tasking conditions. With the growing demands of telehealth, using technology as an objective tool for movement analysis is needed for clinicians and payers. Our findings demonstrate the potential value of the iTUG score to assess and track patient’s progress.

Which functional tasks present the largest deficits for patients with total hip arthroplasty before and six months after surgery? A study of the timed up-and-go test phases

Six to eight months after total hip arthroplasty, patients only attain 80% of the functional level of control groups. Understanding which functional tasks are most affected could help reduce this deficit by guiding rehabilitation towards them. The timed up-and-go test bundles multiple tasks together in one test and is a good indicator of a patient's overall level of function. Previously, biomechanical analysis of its phases was used to identify specific functional deficits in pathological populations. To the best of our knowledge, this analysis has never been performed in patients who have undergone total hip arthroplasty. Seventy-one total hip arthroplasty patients performed an instrumented timed up-and-go test in a gait laboratory before and six months after surgery; fifty-two controls performed it only once. Biomechanical features were selected to analyse the test's four phases (sit-to-stand, walking, turning, turn-to-sit) and mean differences between groups were evaluated for each phase. On average, six months after surgery, patients' overall test time rose to 80% of the mean of the control group. The walking phase was revealed as the main deficiency before and after surgery (-41 ± 47% and -22 ± 32% slower, respectively). High standard deviations indicated that variability between patients was high. On average, patients showed improved results in every phase of the timed up-and-go test six months after surgery, but residual deficits in function differed between those phases. This simple test could be appropriate for quantifying patient-specific deficits in function and hence guiding and monitoring post-operative rehabilitation in clinical settings.

Detecting subtle mobility changes among older adults: the Quantitative Timed Up and Go test

BACKGROUND

The Quantitative Timed Up and Go (QTUG) test uses wearable sensors, containing a triaxial accelerometer and an add-on triaxial gyroscope, to quantify performance during the TUG test with potential to capture more minor changes in mobility.

AIMS

To examine the responsiveness, minimum detectable change (MDC) and observed effect size of QTUG in a cohort of socially active adults aged 50 years and over participating in a structured community exercise program.

METHODS

54 participants (91% females, mean age 63.6 ± 6.5 years) completed repeated QTUG testing under single- and dual-task conditions. Responsiveness of the QTUG was assessed by correlation of change in standard TUG with QTUG change (Pearson's correlation coefficient). MDC and effect sizes (standardized mean difference and Cohen's d) were also calculated for QTUG.

RESULTS

There was a strong positive correlation between change in the standard TUG and change in QTUG (single task r = 0.91, p < 0.001). MDC in QTUG was calculated as 0.77 (Sd, 1.39; ICC 0.96) seconds (single task) and 2.33 (Sd 2.18; ICC 0.85) seconds (dual task). Several QTUG parameters showed improvements in mean values with small effect sizes (sit -to-stand transition time d = 0.418; walk time d = 0.398; cadence d = 0.306, swing time d = 0.314; step time d = 0.479; gait velocity d = 0.365; time to reach turn d = 0.322) under single-task conditions and with a moderate effect size (d = 0.549) in time taken to turn under the dual-task condition.

CONCLUSION

Initial evidence of QTUG's responsiveness to change in mobility in active middle to older age adults has been demonstrated with small to moderate effect sizes observed in specific QTUG parameters.

Validity of Inertial Sensors for Assessing Balance Kinematics and Mobility during Treadmill-Based Perturbation and Dance Training

Inertial sensors (IS) enable the kinematic analysis of human motion with fewer logistical limitations than the silver standard optoelectronic motion capture (MOCAP) system. However, there are no data on the validity of IS for perturbation training and during the performance of dance. The aim of this present study was to determine the concurrent validity of IS in the analysis of kinematic data during slip and trip-like perturbations and during the performance of dance. Seven IS and the MOCAP system were simultaneously used to capture the reactive response and dance movements of fifteen healthy young participants (Age: 18-35 years). Bland Altman (BA) plots, root mean square errors (RMSE), Pearson's correlation coefficients (R), and intraclass correlation coefficients (ICC) were used to compare kinematic variables of interest between the two systems for absolute equivalency and accuracy. Limits of agreements (LOA) of the BA plots ranged from -0.23 to 0.56 and -0.21 to 0.43 for slip and trip stability variables, respectively. The RMSE for slip and trip stabilities were from 0.11 to 0.20 and 0.11 to 0.16, respectively. For the joint mobility in dance, LOA varied from -6.98-18.54, while RMSE ranged from 1.90 to 13.06. Comparison of IS and optoelectronic MOCAP system for reactive balance and body segmental kinematics revealed that R varied from 0.59 to 0.81 and from 0.47 to 0.85 while ICC was from 0.50 to 0.72 and 0.45 to 0.84 respectively for slip-trip perturbations and dance. Results of moderate to high concurrent validity of IS and MOCAP systems. These results were consistent with results from similar studies. This suggests that IS are valid tools to quantitatively analyze reactive balance and mobility kinematics during slip-trip perturbation and the performance of dance at any location outside, including the laboratory, clinical and home settings.

Recovery of mobility function and life-space mobility after ischemic stroke: the MOBITEC-Stroke study protocol

Background

Stroke is a major cause of disability and stroke incidence increases with age. Stroke frequently results in permanent limitations of mobility, and, consequently, the need for the help of others in activities of daily living. In order to optimize rehabilitative efforts and their functional outcomes, detailed knowledge of the functional recovery process, regarding mobility, is needed. Objectives of the MOBITEC-Stroke study are: 1.) To characterize mobility, including lower extremity physical function (LEPF) and life space (the geospatial extent of all of a person’s movements), and changes in mobility within the first year after stroke. 2.) To identify and characterize subgroups with different mobility trajectories. 3.) To evaluate whether changes in LEPF are associated with changes in life-space. 4.) To evaluate participants’ reasons for going outdoors, transportation use, and assistance needed for outdoor movement.

Methods

Patients with incident first stroke who live in their own homes (target N = 59, based on sample size calculation) will be included in this cohort study. At 3, 6, 9, and 12 months after stroke a battery of mobility tests will be performed at the study centre, including laboratory-based tests of balance and strength, and quantitative gait analysis. Life-space assessment (including 1-week GPS measurements) will be performed in participants’ real life. Semantic information on visited locations (reasons for going outdoors, transportation use, assistance needed) will be collected by using interactive digital maps. Linear mixed effects models will be used to model the trajectories of mobility measures for the total sample and for predefined subgroups. As an exploratory analysis, growth mixture models (GMMs) will be used to identify relevant subgroups with different trajectories. Linear mixed effect models will be used to test whether changes in LEPF parameters are associated with changes in life-space. Participants’ motivation for going outdoors, transportation use, and assistance needed for outdoor mobility will be analysed descriptively.

Discussion

A comprehensive and detailed knowledge of recovery patterns will enable the planning of targeted and adaptively tailored rehabilitation measures. Information about patients’ reasons for outdoor mobility will provide the opportunity to define individualized and patient-oriented rehabilitation goals.

Trial registration

ISRCTN85999967 (on 13 August 2020; retrospectively).

Role of Gender in Dual-Tasking Timed Up and Go Tests: A Cross-Sectional Study

Gender plays a role in cognitive performance. Yet the selection of a secondary task, an important paradigm in studies of posture control, has not considered gender as a variable. We explored whether different cognitive tasks differentially influence performance during the Timed Up and Go (TUG) test in men and women. Twenty young adults performed five cognitive tasks while seated and during the TUG test. Men exhibited a slower normalized cadence than women. When seated, women recalled more items than men and men were more accurate in mental calculation task. There were no changes in spatiotemporal measures. We conclude that gender did not play a major role in motor-cognitive interference during dual task TUG test.

The Component Timed-Up-and-Go test: the utility and psychometric properties of using a mobile application to determine prosthetic mobility in people with lower limb amputations

OBJECTIVE

Using a custom mobile application to evaluate the reliability and validity of the Component Timed-Up-and-Go test to assess prosthetic mobility in people with lower limb amputation.

DESIGN

Cross-sectional design.

SETTING

National conference for people with limb loss.

SUBJECTS

A total of 118 people with non-vascular cause of lower limb amputation participated. Subjects had a mean age of 48 (±13.7) years and were an average of 10 years post amputation. Of them, 54% ( n = 64) of subjects were male.

INTERVENTION

None.

MAIN MEASURE

The Component Timed-Up-and-Go was administered using a mobile iPad application, generating a total time to complete the test and five component times capturing each subtask (sit to stand transitions, linear gait, turning) of the standard timed-up-and-go test. The outcome underwent test-retest reliability using intraclass correlation coefficients (ICCs) and convergent validity analyses through correlation with self-report measures of balance and mobility.

RESULTS

The Component Timed-Up-and-Go exhibited excellent test-retest reliability with ICCs ranging from .98 to .86 for total and component times. Evidence of discriminative validity resulted from significant differences in mean total times between people with transtibial (10.1 (SD: ±2.3)) and transfemoral (12.76 (SD: ±5.1) amputation, as well as significant differences in all five component times ( P < .05). Convergent validity of the Component Timed-Up-and-Go was demonstrated through moderate correlations with the PLUS-M ( r_s = -.56).

CONCLUSION

The Component Timed-Up-and-Go is a reliable and valid clinical tool for detailed assessment of prosthetic mobility in people with non-vascular lower limb amputation. The iPad application provided a means to easily record data, contributing to clinical utility.

Impaired balance is related to the progression of diabetic complications in both young and older adults

AIMS

To investigate the balance ability in younger and older adults with diabetes and evaluate the associations between balance ability and microvascular complications.

METHODS

This cross-sectional observational study compared 162 participants and 177 controls with and without type 2 diabetes, respectively. Balance ability was assessed using two static (one-legged stance and postural sway area) and two dynamic (Timed Up and Go [TUG] and Functional Reach) tests. Diabetic microangiopathy was also evaluated.

RESULTS

Participants with diabetes, including both younger (<50years) and older (≥50years) participants, showed significantly worse balance ability in all four tests and were more likely to have a history of falls than the controls (all P<0.01). In all age groups, severe impairment of balance ability was associated with progression of diabetic microvascular complications. In all and older diabetic adults, a longer duration of diabetes (P=0.022) and higher TUG test score (P=0.004), and female sex (P=0.01) and higher TUG score (P=0.001), respectively, were related to a history of falls. On the other hand, among younger diabetic adults, only a non-significant association with longer duration of diabetes (P=0.066) was observed.

CONCLUSIONS

Impaired balance ability correlates with microvascular diabetic complications. Accurate assessment of balance ability in adults with diabetes could predict the risk of falls, particularly benefitting people with diabetic complications.

Validity and repeatability of inertial measurement units for measuring gait parameters

Inertial measurement units (IMUs) are small wearable sensors that have tremendous potential to be applied to clinical gait analysis. They allow objective evaluation of gait and movement disorders outside the clinic and research laboratory, and permit evaluation on large numbers of steps. However, repeatability and validity data of these systems are sparse for gait metrics. The purpose of this study was to determine the validity and between-day repeatability of spatiotemporal metrics (gait speed, stance percent, swing percent, gait cycle time, stride length, cadence, and step duration) as measured with the APDM Opal IMUs and Mobility Lab system. We collected data on 39 healthy subjects. Subjects were tested over two days while walking on a standard treadmill, split-belt treadmill, or overground, with IMUs placed in two locations: both feet and both ankles. The spatiotemporal measurements taken with the IMU system were validated against data from an instrumented treadmill, or using standard clinical procedures. Repeatability and minimally detectable change (MDC) of the system was calculated between days. IMUs displayed high to moderate validity when measuring most of the gait metrics tested. Additionally, these measurements appear to be repeatable when used on the treadmill and overground. The foot configuration of the IMUs appeared to better measure gait parameters; however, both the foot and ankle configurations demonstrated good repeatability. In conclusion, the IMU system in this study appears to be both accurate and repeatable for measuring spatiotemporal gait parameters in healthy young adults.

Instrumented balance and walking assessments in persons with multiple sclerosis show strong test-retest reliability

BACKGROUND

There is a need for objective movement assessment for clinical research trials aimed at improving gait and balance in persons with multiple sclerosis (PwMS). Wireless inertial sensors can accurately measure numerous walking and balance parameters but these measures require evaluation of reliability in PwMS. The current study determined the test-retest reliability of wireless inertial sensor measures obtained during an instrumented standing balance test and an instrumented Timed Up and Go test in PwMS.

METHODS

Fifteen PwMS and 15 healthy control subjects (HC) performed an instrumented standing balance and instrumented Timed Up and Go (TUG) test on two separate days. Ten instrumented standing balance measures and 18 instrumented TUG measures were computed from the wireless sensor data. Intraclass correlation coefficients (ICC) were calculated to determine test-retest reliability of all instrumented standing balance and instrumented TUG measures. Correlations were evaluated between the instrumented standing balance and instrumented TUG measures and self-reported walking and balance performance, fall history, and clinical disability.

RESULTS

For both groups, ICCs for instrumented standing balance measures were best for spatio-temporal measures, while frequency measures were less reliable. All instrumented TUG measures exhibited good to excellent (ICCs > 0.60) test-retest reliability in PwMS and in HC. There were no correlations between self-report walking and balance scores and instrumented TUG or instrumented standing balance metrics, but there were correlations between instrumented TUG and instrumented standing balance metrics and fall history and clinical disability status.

CONCLUSIONS

Measures from the instrumented standing balance and instrumented TUG tests exhibit good to excellent reliability, demonstrating their potential as objective assessments for clinical trials. A subset of the most reliable measures is recommended for measuring walking and balance in clinical settings.

Dual-task gait differences in female and male adolescents following sport-related concussion

Concussion may affect females and males differentially. Identification of gender-related differences after concussion, therefore, may help clinicians with individualized evaluations. We examined potential differences in dual-task gait between females and males after concussion. Thirty-five participants diagnosed with a concussion (49% female, mean age=15.0±2.1 years, 7.5±3.0 days post-injury) and 51 controls (51% female, mean age=14.4±2.1 years) completed a symptom inventory and single/dual-task gait assessment. The primary outcome variable, the dual-task cost, was calculated as the percent change between single-task and dual-task conditions to account for individual differences in spatio-temporal gait variables. No significant differences in symptom severity measured by the post-concussion symptom scale were observed between females (32.0±18.0) and males (27.8±18.2). Compared with males, adolescent females walked with significantly decreased cadence dual-task costs after concussion (-19.7%±10.0% vs. -11.3%±9.2%, p=0.007) when adjusted for age, height, and prior concussion history. No significant differences were found between female and male control groups on other dual-task cost gait measures. Females and males with concussion also walked with significantly shorter stride lengths than controls during single-task (females: 1.13±0.11m vs. 1.26±0.11m, p=0.001; males: 1.14±0.14m vs. 1.22±0.15m, p=0.04) and dual-task gait (females: 0.99±0.10m vs. 1.10±0.11m, p=0.001; males: 1.00±0.13m vs. 1.08±0.14m, p=0.04). Females demonstrated a significantly greater amount of cadence change between single-task and dual-task gait than males after a sport-related concussion. Thus, differential alterations may exist during gait among those with a concussion; gender may be one prominent factor affecting dual-task gait.

Convergent Validity of a Wearable Sensor System for Measuring Sub-Task Performance during the Timed Up-and-Go Test

Background: The timed-up-and-go test (TUG) is one of the most commonly used tests of physical function in clinical practice and for research outcomes. Inertial sensors have been used to parse the TUG test into its composite phases (rising, walking, turning, etc.), but have not validated this approach against an optoelectronic gold-standard, and to our knowledge no studies have published the minimal detectable change of these measurements. Methods: Eleven adults performed the TUG three times each under normal and slow walking conditions, and 3 m and 5 m walking distances, in a 12-camera motion analysis laboratory. An inertial measurement unit (IMU) with tri-axial accelerometers and gyroscopes was worn on the upper-torso. Motion analysis marker data and IMU signals were analyzed separately to identify the six main TUG phases: sit-to-stand, 1st walk, 1st turn, 2nd walk, 2nd turn, and stand-to-sit, and the absolute agreement between two systems analyzed using intra-class correlation (ICC, model 2) analysis. The minimal detectable change (MDC) within subjects was also calculated for each TUG phase. Results: The overall difference between TUG sub-tasks determined using 3D motion capture data and the IMU sensor data was <0.5 s. For all TUG distances and speeds, the absolute agreement was high for total TUG time and walk times (ICC > 0.90), but less for chair activity (ICC range 0.5–0.9) and typically poor for the turn time (ICC < 0.4). MDC values for total TUG time ranged between 2–4 s or 12–22% of the TUG time measurement. MDC of the sub-task times were higher proportionally, being 20–60% of the sub-task duration. Conclusions: We conclude that a commercial IMU can be used for quantifying the TUG phases with accuracy sufficient for clinical applications; however, the MDC when using inertial sensors is not necessarily improved over less sophisticated measurement tools.

Experimental Validation of Depth Cameras for the Parameterization of Functional Balance of Patients in Clinical Tests

In clinical practice, patients’ balance can be assessed using standard scales. Two of the most validated clinical tests for measuring balance are the Timed Up and Go (TUG) test and the MultiDirectional Reach Test (MDRT). Nowadays, inertial sensors (IS) are employed for kinematic analysis of functional tests in the clinical setting, and have become an alternative to expensive, 3D optical motion capture systems. In daily clinical practice, however, IS-based setups are yet cumbersome and inconvenient to apply. Current depth cameras have the potential for such application, presenting many advantages as, for instance, being portable, low-cost and minimally-invasive. This paper aims at experimentally validating to what extent this technology can substitute IS for the parameterization and kinematic analysis of the TUG and the MDRT tests. Twenty healthy young adults were recruited as participants to perform five different balance tests while kinematic data from their movements were measured by both a depth camera and an inertial sensor placed on their trunk. The reliability of the camera’s measurements is examined through the Interclass Correlation Coefficient (ICC), whilst the Pearson Correlation Coefficient (r) is computed to evaluate the correlation between both sensor’s measurements, revealing excellent reliability and strong correlations in most cases.

Validation of a commercial inertial sensor system for spatiotemporal gait measurements in children

Although inertial sensor systems are becoming a popular tool for gait analysis in both healthy and pathological adult populations, there are currently no data on the validity of these systems for use with children. The purpose of this study was to validate spatiotemporal data from a commercial inertial sensor system (MobilityLab) in typically-developing children. Data from 10 children (5 males; 3.0-8.3 years, mean=5.1) were collected simultaneously from MobilityLab and 3D motion capture during gait at self-selected and fast walking speeds. Spatiotemporal parameters were compared between the two methods using a Bland-Altman method. The results indicate that, while the temporal gait measurements were similar between the two systems, MobilityLab demonstrated a consistent bias with respect to measurement of the spatial data (stride length). This error is likely due to differences in relative leg length and gait characteristics in children compared to the MobilityLab adult reference population used to develop the stride length algorithm. A regression-based equation was developed based on the current data to correct the MobilityLab stride length output. The correction was based on leg length, stride time, and shank range-of-motion, each of which were independently associated with stride length. Once the correction was applied, all of the spatiotemporal parameters evaluated showed good agreement. The results of this study indicate that MobilityLab is a valid tool for gait analysis in typically-developing children. Further research is needed to determine the efficacy of this system for use in children suffering from pathologies that impact gait mechanics.

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.

Validity of an inertial measurement unit to assess pelvic orientation angles during gait, sit-stand transfers and step-up transfers: Comparison with an optoelectronic motion capture system

An inertial measurement unit (IMU) allows kinematic evaluation of human motion with fewer operational constraints than a gold standard optoelectronic motion capture (MOCAP) system. The study's aim was to compare IMU and MOCAP measurements of dynamic pelvic orientation angles during different activities of daily life (ADL): gait, sit-to-stand (STS) transfers and block step-up (BS) transfers. A single IMU was attached onto the lower back in seventeen healthy participants (8F/9 M, age 19-31 years; BMI < 25) and optical skin markers were attached onto anatomical pelvic landmarks for MOCAP measurements. Comparisons between IMU and MOCAP by Bland-Altman plots demonstrated that measurements were between 2SD of the absolute difference and Pearson's correlation coefficients were between 0.85 and 0.94. Frontal plane pelvic angle estimations achieved a RMSE in the range of [2.7°-4.5°] and sagittal plane measurements achieved a RMSE in the range of [2.7°-8.9°] which were both lowest in gait. Waveform peak detection times demonstrated ICCs between 0.96 and 1.00. These results are in accordance to other studies comparing IMU and MOCAP measurements with different applications and suggest that an IMU is a valid tool to measure dynamic pelvic angles during various activities of daily life which could be applied to monitor rehabilitation in a wide variety of musculoskeletal disorders.