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We investigated the effect of deep brain stimulation on dynamic balance during gait in Parkinson's disease with motion sensor measurements and predicted their values from disease-related factors. We recruited twenty patients with Parkinson's disease treated with bilateral subthalamic stimulation for at least 12 months and 24 healthy controls. Six monitors with three-dimensional gyroscopes and accelerometers were placed on the chest, the lumbar region, the two wrists, and the shins. Patients performed the instrumented Timed Up and Go test in stimulation OFF, stimulation ON, and right- and left-sided stimulation ON conditions. Gait parameters and dynamic balance parameters such as double support, peak turn velocity, and the trunk's range of motion and velocity in three dimensions were analyzed. Age, disease duration, the time elapsed after implantation, the Hoehn-Yahr stage before and after the operation, the levodopa, and stimulation responsiveness were reported. We individually calculated the distance values of stimulation locations from the subthalamic motor center in three dimensions. Sway values of static balance were collected. We compared the gait parameters in the OFF and stimulation ON states and controls. With cluster analysis and a machine-learning-based multiple regression method, we explored the predictive clinical factors for each dynamic balance parameter (with age as a confounder). The arm movements improved the most among gait parameters due to stimulation and the horizontal and sagittal trunk movements. Double support did not change after switching on the stimulation on the group level and did not differ fromcontrol values. Individual changes in double support and horizontal range of trunk motion due to stimulation could be predicted from the most disease-related factors and the severity of the disease; the latter also from the stimulation-related changes in the static balance parameters. Physiotherapy should focus on double support and horizontal trunk movements when treating patients with subthalamic deep brain stimulation. [ABSTRACT FROM AUTHOR]

We investigated the effect of deep brain stimulation on dynamic balance during gait in Parkinson's disease with motion sensor measurements and predicted their values from disease-related factors. We recruited twenty patients with Parkinson's disease treated with bilateral subthalamic stimulation for at least 12 months and 24 healthy controls. Six monitors with three-dimensional gyroscopes and accelerometers were placed on the chest, the lumbar region, the two wrists, and the shins. Patients performed the instrumented Timed Up and Go test in stimulation OFF, stimulation ON, and right- and left-sided stimulation ON conditions. Gait parameters and dynamic balance parameters such as double support, peak turn velocity, and the trunk's range of motion and velocity in three dimensions were analyzed. Age, disease duration, the time elapsed after implantation, the Hoehn-Yahr stage before and after the operation, the levodopa, and stimulation responsiveness were reported. We individually calculated the distance values of stimulation locations from the subthalamic motor center in three dimensions. Sway values of static balance were collected. We compared the gait parameters in the OFF and stimulation ON states and controls. With cluster analysis and a machine-learning-based multiple regression method, we explored the predictive clinical factors for each dynamic balance parameter (with age as a confounder). The arm movements improved the most among gait parameters due to stimulation and the horizontal and sagittal trunk movements. Double support did not change after switching on the stimulation on the group level and did not differ from control values. Individual changes in double support and horizontal range of trunk motion due to stimulation could be predicted from the most disease-related factors and the severity of the disease; the latter also from the stimulation-related changes in the static balance parameters. Physiotherapy should focus on double support and horizontal trunk movements when treating patients with subthalamic deep brain stimulation.

• the curative outcomes of BDSF and CFIX methods were juxtaposed for the management of Pauwels III femoral neck fractures in young and middle-aged individuals. • Compared to the CFIX group, the BDSF group displayed a lower incidence of bone nonunion, internal fixation failure, and femoral head necrosis. • the BDSF approach presents a shorter healing duration and a diminished incidence of bone nonunion, internal fixation failure, femoral head necrosis, and femoral neck shortening. Traditional treatment methods have certain limitations. In recent years, the technique of internal fixation with double-plane double-supported screws based on X-ray images has been proposed to improve the therapeutic effect. The main objective of this research was to examine the effectiveness of the X-ray image-based bi-planar double-braced screw internal fixation technique. During surgery, the procedure was determined based on X-ray images, followed by an open reduction procedure at the fracture site, and finally internal fixation using bi-planar double-support screws. All patients were successfully treated with X-ray image-based bi-planar double support screw fixation. After surgery, X-ray images showed a good reduction of the fracture site without significant loosening or failure of the internal fixation. At the postoperative follow-up, the patient's pain symptoms were significantly relieved, and no significant complications occurred during recovery. [ABSTRACT FROM AUTHOR]

Objective: To identify and summarize biomechanical assessment approaches in interlimb coordination on poststroke gait. Introduction: Interlimb coordination involves complex neurophysiological mechanisms that can be expressed through the biomechanical output. The deepening of this concept would have a significant contribution in gait rehabilitation in patients with an asymmetric neurological impairment as poststroke adults. Inclusion criteria: Poststroke adults (>19 years old), with assessment of interlimb coordination during gait, in an open context, according to the Population, Concept, Context framework. Methods: A literature search was performed in PubMed, Web of Science™, Scopus, and gray literature in Google Scholar™, according to the PRISMA-ScR recommendations. Studies written in Portuguese or English language and published between database inception and 14 November 2021 were included. Qualitative studies, conference proceedings, letters, and editorials were excluded. The main conceptual categories were “author/year”, “study design”, “participant’s characteristics”, “walking conditions”, “instruments” and “outcomes”. Results: The search identified 827 potentially relevant studies, with a remaining seven fulfilling the established criteria. Interlimb coordination was assessed during walking in treadmill (n = 3), overground (n = 3) and both (n = 1). The instruments used monitored electromyography (n = 2), kinetics (n = 2), and kinematics (n = 4) to assess spatiotemporal parameters (n = 4), joint kinematics (n = 2), anteroposterior ground reaction forces (n = 2), and electromyography root mean square (n = 2) outcomes. These outcomes were mostly used to analyze symmetry indices or ratios, to calculate propulsive impulse and external mechanical power produced on the CoM, as well as antagonist coactivation. Conclusions: Assessment of interlimb coordination during gait is important for consideration of natural auto-selected overground walking, using kinematic, kinetic, and EMG instruments. These allow for the collection of the main biomechanical outcomes that could contribute to improve better knowledge of interlimb coordination assessment in poststroke patients.

The conventional use of inverse dynamics applied to gait analysis involves the estimation of joint forces and moments based on kinematic data, anthropometric parameters and force plate data. The procedure uses the measured ground reactions and, beginning with those segments in contact with the ground, calculates joint forces and moments at each successive segment. However, this procedure cannot always be applied. There are laboratories that do not have force platforms, or situations in which measurements must be made outside the laboratory. Force plate data only gives the ground forces and moments resultants. When using multi-segment foot models, additional assumptions must be made to distribute the resultants among the different segments in contact with ground. In these situations, a possible solution is the use of inverse dynamics based only on kinematics. This procedure usually starts with the non-contact segments (head, hands, swinging foot in single support phase) and ends with the foot or feet in contact. In the double-support phase of gait, the ground reaction forces include 12 unknowns, which makes the inverse dynamics problem indeterminate. To solve the indeterminacy, the Smooth Transition Assumption (STA) was used in this work. This algorithm is based on the assumption that the reaction forces and moments at the trailing foot decay according to a certain law that combines exponential and linear functions, reducing the number of unknowns to six. In this work, ground reaction force and moments calculated using different body pose reconstruction methods were compared to data provided by force plates. Results depend greatly on the body pose reconstruction method used. Results show that the imposition of kinematic constrains can lead to worse results in the kinetic results if the multibody model is too simplistic. To get good comparison results between inverse dynamics methods based only on kinematics and classical procedures using force plates data, dynamic residuals should be as small as possible. In the single support phase, differences will be identically equal to the dynamic residuals, but higher in the double support phase because of the errors introduced by the transition functions. [ABSTRACT FROM AUTHOR]

Wearable sensor systems are of increasing interest in clinical gait analysis. However, little information about gait dynamics of patients under free living conditions is available, due to the challenges of integrating such systems unobtrusively into a patient’s everyday live. To address this limitation, new, fully integrated low power sensor insoles are proposed, to target applications particularly in home-monitoring scenarios. The insoles combine inertial as well as pressure sensors and feature wireless synchronization to acquire biomechanical data of both feet with a mean timing offset of 15.0 μs. The proposed system was evaluated on 15 patients with mild to severe gait disorders against the GAITRite® system as reference. Gait events based on the insoles’ pressure sensors were manually extracted to calculate temporal gait features such as double support time and double support. Compared to the reference system a mean error of 0.06 s ±0.06 s and 3.89 % ±2.61 % was achieved, respectively. The proposed insoles proved their ability to acquire synchronized gait parameters and address the requirements for home-monitoring scenarios, pushing the boundaries of clinical gait analysis.

The aim of this study was to determine the gait features that are most suitable for the quantified assessment of the severity of Parkinson's disease (PD). This study computed the mean and variance of the four phases of gait intervals, i.e., stride, swing, stance and double-support intervals, and lateral difference to determine the difference between three groups, i.e., control subjects and PD patients with two severity levels (early and advanced stage) of the disease, PD1 and PD2. Data from 31 subjects were used in the study. The data were obtained from the public database (16 control healthy subjects, 6 Parkinson's disease patients with early stages, and 9 Parkinson's disease patients with advanced stages based on the Hoehn and Yahr scale). The main outcome measure of the study was the group difference of the four gait interval parameters and the statistical significance of this difference. The results show that there was a significant increase in the variance of the four gait intervals with the severity of the disease. However, there was no significant difference in the mean values between the three groups. It was also observed that the fraction corresponding to the double-support interval was significantly higher for PD patients. This study has shown that the variance of the gait parameters and the fraction of double-support interval are associated with the severity of PD and may be suitable measures for a quantified evaluation of the disease. [ABSTRACT FROM AUTHOR]

Much is still unknown about walking stability, including which aspects of gait contribute to higher stability. Walking stability appears to be related to walking speed, although the exact relationship is unclear. As walking speed decreases, the double support (DS) period of gait increases both in time and as a percentage of the gait cycle. Because humans have more control over their center of mass movement during DS, increasing DS duration may alter stability. This study examined how human gait is affected by changing DS percentage independent of walking speed. Sixteen young, healthy adults walked on a treadmill at a single speed for six one-minute trials. These trials included normal gait as well as longer- and shorter-than-normal DS percentage gaits. Subjects were consistently able to decrease DS percentage but had difficulty increasing DS percentage. In some cases, subjects altered their cadence when changing DS percentage, particularly when attempting to increase DS percentage. The changes to gait when decreasing DS percentage were similar to changes when increasing walking speed but occurred mainly during the swing period. These changes include increased hip and knee flexion during the swing period, increased swing foot height, and larger magnitude peaks in ground reaction forces. The changes in gait when attempting to increase DS percentage trended toward changes when decreasing walking speed. Altering DS percentage induced gait changes that were similar to, yet clearly distinct from, gait changes due to walking speed. Further, the difficulty of increasing DS percentage when walking at a constant speed suggests that people walk more slowly when they want to increase time spent in DS. [ABSTRACT FROM AUTHOR]

The aim of this study was to determine the gait features that are most suitable for the quantified assessment of the severity of Parkinson’s disease (PD). This study computed the mean and variance of the four phases of gait intervals, i.e., stride, swing, stance and double-support intervals, and lateral difference to determine the difference between three groups, i.e., control subjects and PD patients with two severity levels (early and advanced stage) of the disease, PD1 and PD2. Data from 31 subjects were used in the study. The data were obtained from the public database (16 control healthy subjects, 6 Parkinson’s disease patients with early stages, and 9 Parkinson’s disease patients with advanced stages based on the Hoehn and Yahr scale). The main outcome measure of the study was the group difference of the four gait interval parameters and the statistical significance of this difference. The results show that there was a significant increase in the variance of the four gait intervals with the severity of the disease. However, there was no significant difference in the mean values between the three groups. It was also observed that the fraction corresponding to the double-support interval was significantly higher for PD patients. This study has shown that the variance of the gait parameters and the fraction of double-support interval are associated with the severity of PD and may be suitable measures for a quantified evaluation of the disease.

As lameness detection in dairy cattle using visual locomotion scoring is cumbersome and subjective, research efforts are dedicated to develop automatic lameness detection systems. ‘Tender hoof placement’ and the distribution of the body weight over the four legs are possible lameness indicators, but no research exists on how to derive from automatically measured gait characteristics. This study aims to derive new variables related to the (i) landing, full weight bearing and lifting phases of a stance time and the (ii) time spent on combinations of legs during the different phases of the gait cycle from cow gait recordings on a dedicated pressure mat, known as the Gaitwise. Data of 9 non-lame, 11 mildly lame and 12 severely lame cows were gathered. For all measurements, each variable was calculated per leg or combination of legs, after which the group means of each variable were compared between the three lameness statuses using a one-way ANOVA analysis. Landing and lifting variables indicated that the proportion of time for hoof placement and hoof lifting during the total stance time was longer in lame cows, and that the proportion of full weight bearing time was shorter. Lame cows were thus more careful to place and retract the hind feet in the case of a hind-lame leg. Support time variables indicated that lame cows increased the percentage triple support time (i.e time spent with three feet on the ground during walking) and lowered the percentage double support (i.e. time spent with two legs on the ground). Also, double support combinations on the same side of the body were preferred above diagonal combinations. The newly defined gait variables indeed reflect tenderness of hoof placement and body weight distribution and hence seem useful for discriminating between non-lame, mildly lame and severely lame cows. However, several of these interesting variables may have to be combined to obtain automatic lameness detection with sufficient accuracy. [ABSTRACT FROM AUTHOR]

Muscle--tendon units about the ankle joint generate a burst of positive power during the step-to-step transition in human walking, termed ankle push-off, but there is no scientific consensus on its functional role. A central question embodied in the biomechanics literature is: does ankle push-off primarily contribute to leg swing, or to center of mass (COM) acceleration? This question has been debated in various forms for decades. However, it actually presents a false dichotomy, as these two possibilities are not mutually exclusive. If we ask either question independently, the answer is the same: yes! (1) Does ankle push-off primarily contribute to leg swing acceleration? Yes. (2) Does ankle push-off primarily contribute to COM acceleration? Yes. Here, we summarize the historical debate, then synthesize the seemingly polarized perspectives and demonstrate that both descriptions are valid. The principal means by which ankle push-off affects COM mechanics is by a localized action that increases the speed and kinetic energy of the trailing push-off limb. Because the limb is included in body COM computations, this localized segmental acceleration also accelerates the COM, and most of the segmental energy change also appears as COM energy change. Interpretation of ankle mechanics should abandon an either/ or contrast of leg swing versus COM acceleration. Instead, ankle push-off should be interpreted in light of both mutually consistent effects. This unified perspective informs our fundamental understanding of the role of ankle push-off, and has important implications for the design of clinical interventions (e.g. prostheses, orthoses) intended to restore locomotor function to individuals with disabilities. [ABSTRACT FROM AUTHOR]

Continuous monitoring of natural human gait in real-life environments is essential in many applications including disease monitoring, rehabilitation, and professional sports. Wearable inertial measurement units are successfully used to measure body kinematics in real-life environments and to estimate total walking ground reaction forces GRF(t) using equations of motion. However, for inverse dynamics and clinical gait analysis, the GRF(t) of each foot is required separately. Using an experimental dataset of 1243 tri-axial separate-foot GRF(t) time histories measured by the authors across eight years, this study proposes the ‘Twin Polynomial Method’ (TPM) to estimate the tri-axial left and right foot GRF(t) signals from the total GRF(t) signals. For each gait cycle, TPM fits polynomials of degree five, eight, and nine to the known single-support part of the left and right foot vertical, anterior-posterior, and medial-lateral GRF(t) signals, respectively, to extrapolate the unknown double-support parts of the corresponding GRF(t) signals. Validation of the proposed method both with force plate measurements (gold standard) in the laboratory, and in real-life environment showed a peak-to-peak normalized root mean square error of less than 2.5%, 6.5% and 7.5% for the estimated GRF(t) signals in the vertical, anterior-posterior and medial-lateral directions, respectively. These values show considerable improvement compared with the currently available GRF(t) decomposition methods in the literature.

Vestibular asymmetry is a common cause of dizziness in the elderly, for whom it precipitates the risk of falling. Previous studies have shown that those with vestibular asymmetry displayed an altered variability in double support time (DST) compared to controls. However, swing time (SwT) variability findings are conflicting. In this study, we investigated if vestibular asymmetry might be causally connected to increased DST variability. We studied a group of eight elderly fallers with wrist fractures across three months, during which time four of them regained vestibular symmetry while four others developed an asymmetry. We evaluated the variability of DST and SwT, both when the participants suffered from vestibular asymmetry and when they did not. On average, variability in DST was significantly greater by 2.38%CV (coefficient of variation) when participants scored positive for vestibular asymmetry compared to when not, t(5)=4.39, p=0.01, ξ=1.67. In contrast, SwT variability differed non-significantly by 0.44%CV when participants had tested positive versus negative for vestibular asymmetry, t(5)=-0.87, p=0.39, ξ=-0.29. As a possible rationale for our results, we propose that increased DST variability may be the result of a re-stabilization strategy. Further research on DST variability and its correlation to the duration of vestibular asymmetry is recommended. [ABSTRACT FROM AUTHOR]