Accuracy, concurrent validity, and test-retest reliability of pressure-based insoles for gait measurement in chronic stroke patients.

Introduction: Wearables are potentially valuable tools for understanding mobility behavior in individuals with neurological disorders and how it changes depending on health status, such as after rehabilitation. However, the accurate detection of gait events, which are crucial for the evaluation of gait performance and quality, is challenging due to highly individual-specific patterns that also vary greatly in movement and speed, especially after stroke. Therefore, the purpose of this study was to assess the accuracy, concurrent validity, and test-retest reliability of a commercially available insole system in the detection of gait events and the calculation of stance duration in individuals with chronic stroke. Methods: Pressure insole data were collected from 17 individuals with chronic stroke during two measurement blocks, each comprising three 10-min walking tests conducted in a clinical setting. The gait assessments were recorded with a video camera that served as a ground truth, and pressure insoles as an experimental system. We compared the number of gait events and stance durations between systems. Results and discussion: Over all 3,820 gait events, 90.86% were correctly identified by the insole system. Recall values ranged from 0.994 to 1, with a precision of 1 for all measurements. The F1 score ranged from 0.997 to 1. Excellent absolute agreement (Intraclass correlation coefficient, ICC = 0.874) was observed for the calculation of the stance duration, with a slightly longer stance duration recorded by the insole system (difference of -0.01 s). Bland-Altmann analysis indicated limits of agreement of 0.33 s that were robust to changes in walking speed. This consistency makes the system well-suited for individuals post-stroke. The test-retest reliability between measurement timepoints T1 and T2 was excellent (ICC = 0.928). The mean difference in stance duration between T1 and T2 was 0.03 s. We conclude that the insole system is valid for use in a clinical setting to quantitatively assess continuous walking in individuals with stroke.

Hip and trunk kinematics during reaching on a mobile and stable seat.

Reaching movements are often used to assess selective trunk control in people with neurological conditions. Also, it is known that reaching performance after stroke is increased through training on a mobile seat compared to conventional physical therapy. However, the effect of a mobile seat on joint kinematics has not yet been investigated. This study aimed to quantify differences in the range of motion of the hip and trunk during reaching exercises on a mobile and stable sitting surface. Fifteen healthy participants performed reaching beyond arm's length on a mobile and a stable seat in four different directions: ipsilateral, anterior, contralateral, and contralateral diagonal. Biomechanical data were collected, including kinematics of the hip and trunk, and surface electromyography of the trunk muscles. The mobile sitting surface led to a higher range of motion in the trunk and the hip in the frontal and sagittal plane, but not in the rotational plane. Differences between reaching directions were found in all joint directions, except that of trunk flexion. Hence, movement patterns of the hip and trunk differ during reaching on different sitting surfaces and in different directions. A larger range of motion in the frontal or sagittal plane while training on the mobile seat provides added neuromuscular stimuli to the trunk muscles (= a higher demand on trunk muscles), which could result in more efficient training and therefore, increased trunk control after stroke. However, this has to be investigated in a future study with people after stroke.

Surface electromyographic activity of trunk muscles during trunk control exercises for people after stroke; effect of a mobile and stable seat for rehabilitation.

The aim of this study was to explore differences in trunk muscle activity on a stable and mobile seat for people after stroke and healthy participants. Trunk control exercises are known to have a beneficial effect on trunk control, balance, and mobility after stroke. The effect of such exercises could be enhanced by the use of a mobile seat to provide further training stimuli. However, little research on the musculoskeletal effects of trunk training on mobile seats has been carried out. On a stable and a mobile seat, thirteen people after stroke and fifteen healthy participants performed two selective trunk control exercises, which were lateral flexion initiated by the pelvis and the thorax. The maximal surface electromyography relative to static sitting of the muscles multifidus, erector spinae, and obliquus externus was recorded bilaterally. The effects of group, seat condition, trunk control exercise, and muscle side were investigated employing within-subject linear-mixed-models. Compared to the stable seat, the maximal muscle activity of people after stroke on the mobile seat was higher during the thorax-initiated exercise and lower during the pelvis-initiated exercise. Healthy participants showed opposite results with higher muscle activity on the mobile seat during the pelvis-initiated exercise. For trunk control training on a mobile seat with high muscle activation people after stroke should perform trunk control exercises initiated by the thorax, for training with lower muscle activity people after stroke should initiate selective trunk movements by the pelvis. The results can support the planning of progressive trunk control rehabilitation programs.

Head kinematics in patients with neck pain compared to asymptomatic controls: a systematic review.

BACKGROUND: Neck pain is one of the most common musculoskeletal disorders encountered by healthcare providers. A precise assessment of functional deficits, including sensorimotor control impairment, is regarded necessary for tailored exercise programmes. Sensorimotor control can be measured by kinematic characteristics, such as velocity, acceleration, smoothness, and temporal measures, or by assessing movement accuracy. This systematic review aims to identify movement tasks and distinct outcome variables used to measure kinematics and movement accuracy in patients with neck pain and present their results in comparison to asymptomatic controls. METHODS: Electronic searches were conducted in MEDLINE, PEDro, Cochrane Library and CINAHL databases from inception to August 2020. Risk of bias of included studies was assessed. Movement tasks and specific outcome parameters used were collated. The level of evidence for potential group differences in each outcome variable between patients with neck pain and controls was evaluated. RESULTS: Twenty-seven studies examining head kinematics and movement accuracy during head-aiming, functional and unconstrained movement tasks of the head were included. Average Risk of Bias of included studies was moderate. In total, 23 different outcome variables were assessed. A strong level of evidence for an increased movement time and for an increased number of errors during head aiming tasks was found. Moderate evidence was found in traumatic neck pain for a decreased mean velocity, peak acceleration, and reaction time, and for point deviation and time on target during head aiming tasks. Moderate evidence was found for decreased acceleration during unconstrained movements, too. Results on the remaining movement task and outcome variables showed only limited, very limited or even conflicting level of evidence for patients with neck pain to differ from controls. CONCLUSIONS: Sensorimotor control in NP in the way of kinematic and movement accuracy characteristics of head motion was examined in head aiming, functional or unconstrained movement tasks. The results from this review indicate that for some characteristics that describe sensorimotor control, patients with NP differ from healthy controls. SYSTEMATIC REVIEW REGISTRATION: PROSPERO registration number: CRD42020139083.

A Two Joint Neck Model to Identify Malposition of the Head Relative to the Thorax.

Neck pain is a frequent health complaint. Prolonged protracted malpositions of the head are associated with neck pain and headaches and could be prevented using biofeedback systems. A practical biofeedback system to detect malpositions should be realized with a simple measurement setup. To achieve this, a simple biomechanical model representing head orientation and translation relative to the thorax is introduced. To identify the parameters of this model, anthropometric data were acquired from eight healthy volunteers. In this work we determine (i) the accuracy of the proposed model when the neck length is known, (ii) the dependency of the neck length on the body height, and (iii) the impact of a wrong neck length on the models accuracy. The resulting model is able to describe the motion of the head with a maximum uncertainty of 5 mm only. To achieve this high accuracy the effective neck length must be known a priory. If however, this parameter is assumed to be a linear function of the palpable neck length, the measurement error increases. Still, the resulting accuracy can be sufficient to identify and monitor a protracted malposition of the head relative to the thorax.

Concurrent validity and reliability of a mobile tracking technology to measure angular and linear movements of the neck.

The neck can be moved in six degrees of freedom. Current 3D-optoelectronic motion-capture systems capable of measuring these movements are inappropriate for use in clinical practice because they are stationary, expensive and time-consuming. We therefore developed a less complex 3D-tracking technology based on Steam®VR to measure six degrees of freedom in a clinical setting. The aim of this study was to assess the validity and reliability of this system. The developed prototype consists of two infrared-emitting lighthouses and sensors, mounted on the participant's helmet and trunk belt, to detect the orientation of the head and trunk. The system was evaluated by means of an infrared light-reflecting marker tracking system. Twenty healthy participants, equipped with these sensors and markers, performed thirteen neck movement tasks. Linear and angular movements were measured. These tasks were repeated after six to eight days to assess test-retest reliability. Concurrent validity was assessed by the root mean square error, and reliability with generalizability theory. With an average root mean square error between 1.2 and 2.0° in angular and 0.4-0.5 cm in linear movements, the prototype was shown to precisely track these movements. Reliability of the prototype and the reference system was comparable for all tasks. A high contribution of participant's variability to the observed variance was generally detected, with the exception of joint repositioning error and upper cervical flexion. The reliability was task-specific and did not differ between the systems. The prototype system was shown to be valid, although the reliability of the repositioning and upper cervical flexion tests needs to be reconsidered.

Influence of Functional Rider and Horse Asymmetries on Saddle Force Distribution During Stance and in Sitting Trot.

Asymmetric forces exerted on the horse's back during riding are assumed to have a negative effect on rider-horse interaction, athletic performance, and health of the horse. Visualized on a saddle pressure mat, they are initially blamed on a nonfitting saddle. The contribution of horse and rider to an asymmetric loading pattern, however, is not well understood. The aim of this study was to investigate the effects of horse and rider asymmetries during stance and in sitting trot on the force distribution on the horse's back using a saddle pressure mat and motion capture analysis simultaneously. Data of 80 horse-rider pairs (HRP) were collected and analyzed using linear (mixed) models to determine the influence of rider and horse variables on asymmetric force distribution. Results showed high variation between HRP. Both rider and horse variables revealed significant relationships to asymmetric saddle force distribution (P < .001). During sitting trot, the collapse of the rider in one hip increased the force on the contralateral side, and the tilt of the rider's upper body to one side led to more force on the same side of the pressure mat. Analyzing different subsets of data revealed that rider posture as well as horse movements and conformation can cause an asymmetric force distribution. Because neither horse nor rider movement can be assessed independently during riding, the interpretation of an asymmetric force distribution on the saddle pressure mat remains challenging, and all contributing factors (horse, rider, saddle) need to be considered.

Intra-rater reliability of determining positions of cervical spinous processes and measuring their relative distances : An update to define rigid bodies of the cervical spine in a movement laboratory setting.

OBJECTIVES: A reliable detection of bony landmarks of the spine is necessary in order to determine rigid bodies and to reduce the variability of marker placement in a movement laboratory setting. In a first study on the thoracic and lumbar spine, we demonstrated that placing markers on their relative positions between two major landmarks was superior to palpation of specific bony landmarks. The aims of this study were to examine the intra-rater reliability when palpating for spinous processes (SPs) of the second (C2) and seventh cervical vertebrae (C7), to determine the distances between C2 and C7 and the relative position of C7 along the length between C2 and the posterior superior iliac spine (PSIS) level. RESULTS: The intra-rater reliability in determining the distance between C2 and C7 was found to be substantial, with an intra-rater reliability of 0.75 (95% confidence limits 0.55-0.99) and a standard error of the measurement of 0.34 cm. The relative distance of C7 along the total C2-PSIS length was estimated to be 11.5%. The determination of the relative positions of spinal landmarks through measurement is considered superior to their palpation, because it relies on a reproducible and comparable definition of rigid bodies.

Accuracy of KinectOne to quantify kinematics of the upper body.

Motion analysis systems deliver quantitative information, e.g. on the progress of rehabilitation programs aimed at improving range of motion. Markerless systems are of interest for clinical application because they are low-cost and easy to use. The first generation of the Kinect™ sensor showed promising results in validity assessment compared to an established marker-based system. However, no literature is available on the validity of the new 'Kinect™ for Xbox one' (KinectOne) in tracking upper body motion. Consequently, this study was conducted to analyze the accuracy and reliability of the KinectOne in tracking upper body motion. Twenty subjects performed shoulder abduction in frontal and scapula plane, flexion, external rotation and horizontal flexion in two conditions (sitting and standing). Arm and trunk motion were analyzed using the KinectOne and compared to a marker-based system. Comparisons were made using Bland Altman statistics and Coefficient of Multiple Correlation. On average, differences between systems of 3.9±4.0° and 0.1±3.8° were found for arm and trunk motion, respectively. Correlation was higher for the arm than for the trunk motion. Based on the observed bias, the accuracy of the KinectOne was found to be adequate to measure arm motion in a clinical setting. Although trunk motion showed a very low absolute bias between the two systems, the KinectOne was not able to track small changes over time. Before the KinectOne can find clinical application, further research is required analyzing whether validity can be improved using a customized tracking algorithm or other sensor placement, and to analyze test-retest reliability.

Measuring lumbar reposition accuracy in patients with unspecific low back pain: systematic review and meta-analysis.

STUDY DESIGN: Systematic review and meta-analysis. OBJECTIVE: To evaluate if patients with nonspecific chronic low back pain (NSCLBP) show a greater lumbar reposition error (RE) than healthy controls. SUMMARY OF BACKGROUND DATA: Studies on lumbar RE in patients with NSCLBP present conflicting results. METHODS: A systematic review and meta-analysis of the available literature were performed to evaluate differences in RE between patients with NSCLBP and healthy controls. Data on absolute error, constant error (CE), and variable error were extracted and effect sizes (ESs) were calculated. For the CE flexion pattern and active extension pattern, subgroups of patients with NSCLBP were analyzed. Results of homogeneous studies were pooled. Measurement protocols and study outcomes were compared. The quality of reporting and the authors' appraisal of risk of bias were investigated. RESULTS: The original search revealed 178 records of which 13 fulfilled the inclusion criteria. The majority of studies showed that patients with NSCLBP produced a significantly larger absolute error (ES, 0.81; 95% confidence interval [95% CI], 0.13-1.49) and variable error (ES, 0.57; 95% CI, 0.05-1.09) compared with controls. CE is direction specific in flexion and active extension pattern subgroups of patients with NSCLBP (ES, 0.39; 95% CI, -1.09 to 0.3) and ES, 0.18; 95% CI, -0.3 to 0.65, respectively). The quality of reporting and the authors' appraisal of risk of bias varied considerably. The applied test procedures and instrumentation varied between the studies, which hampered the comparability of studies. CONCLUSION: Although patients with NSCLBP seemed to produce a larger lumbar RE compared with healthy controls, study limitations render firm conclusions unsafe. Future studies should pay closer attention to power, precision, and reliability of the measurement approach, definition of outcome measures, and patient selection. We recommend a large, well-powered, prospective randomized control study that uses a standardized measurement approach and definitions for absolute error, CE, and variable error to address the hypothesis that proprioception may be impaired with CLBP.

Extension and flexion in the upper cervical spine in neck pain patients.

Neck pain is a common problem in the general population with high risk of ongoing complaints or relapses. Range of motion (ROM) assessment is scientifically established in the clinical process of diagnosis, prognosis and outcome evaluation in neck pain. Anatomically, the cervical spine (CS) has been considered in two regions, the upper and lower CS. Disorders like cervicogenic headache have been clinically associated with dysfunctions of the upper CS (UCS), yet ROM tests and measurements are typically conducted on the whole CS. A cross-sectional study assessing 19 subjects with non-specific neck pain was undertaken to examine UCS extension-flexion ROM in relation to self-reported disability and pain (via the Neck Disability Index (NDI)). Two measurement devices (goniometer and electromagnetic tracking) were employed and compared. Correlations between ROM and the NDI were stronger for the UCS compared to the CS, with the strongest correlation between UCS flexion and the NDI-headache (r = -0.62). Correlations between UCS and CS ROM were fair to moderate, with the strongest correlation between UCS flexion and CS extension ROM (r = -0.49). UCS flexion restriction is related to headache frequency and intensity. Consistency and agreement between both measurement systems and for all tests was high. The results demonstrate that separate UCS ROM assessments for extension and flexion are useful in patients with neck pain.

Determination of thoracic and lumbar spinal processes by their percentage position between C7 and the PSIS level.

BACKGROUND: Accurate measurements of spinal movement require reliable determination of anatomical landmarks. Current methods of identifying these are not sufficiently reliable or valid for this purpose. A reliable and convenient method of placing markers on selected vertebra is needed to compare measurements between different testers, subjects and sessions. FINDINGS: Two testers palpated T4, T7, T10, L1 and L4 spinal processes according to established criteria. They measured the position of spinal processes between C7 and the Posterior Superior Iliac Spine (PSIS) at the Pelvis independently using a flexible ruler placed on the spine. Subjects with a wide range of body heights but without visible spinal deformities were recruited for measurements. Reliability was calculated using absolute and relative values. Mean percentage position and 95% Confidence Intervals were calculated using the mean of both testers' measurement for all subjects.Twenty-two subjects participated. The mean distance between C7 and the PSIS level was 50.9 cm (SD: 3.5 cm). Relative reliability for all spinal processes was almost perfect (ICC: > 0.9). Absolute reliability values showed high agreement between testers. Percentage position of T4 was found to be situated 21% along the distance between C7 and the PSIS level, T7 at 39%, T10 at 54.1%, L1 at 70.9% and L4 at 86.1% accordingly. 95% Confidence intervals around mean percentage positions had a maximum at L1 with 2.8% range from upper to lower limit. CONCLUSIONS: The distance of three thoracic and two lumbar spinal processes can be reliably and accurately measured by independent testers, using a flexible ruler. Percentage positions between C7 and PSIS level correspond to spinal processes for subjects without visible deformities in the sagittal and frontal plane.