Cyclograms Reveal Alteration of Inter-Joint Coordination during Gait in People with Multiple Sclerosis Minimally Disabled

Subtle alterations of gait patterns in people with Multiple Sclerosis (pwMS) with minimal or no disability often coexist with normal spatio-temporal parameters. Here, we retrospectively in- vestigate the existence of possible anomalies in lower limb inter-joint coordination (i.e., the functional relationship between joint pairs) in pwMS with apparently physiologic gait features. Twenty-seven pwMS with Expanded Disability Status Scale scores 2, and 27 unaffected age-and-sex-matched individuals, were tested using 3D computerized gait analysis. Raw data were processed to extract the main spatio-temporal parameters and the kinematics in the sagittal plane at the hip, knee, and ankle joints. Angle-angle diagrams (cyclograms) were obtained by coupling the flexion-extension values for the hip-knee and knee-ankle joint pairs at each point of the gait cycle. Cyclogram area, perimeter, and dimensionless ratio were employed to quantify inter-joint coordination. The results demonstrate that cyclograms of pwMS are characterized by significantly reduced perimeters for both investigated joint pairs and reduced area at the hip–knee joint pair. In the latter pair, the differences between groups involved the entire swing phase. For the knee-ankle pair, the average cyclogram of pwMS departed from normality from the late stance until the mid-swing phase. Such findings suggest that inter-joint coordination is impaired even in minimally disabled pwMS who exhibit a normal gait pattern in terms of spatio-temporal parameters. The quantitative and qualitative study of cyclogram features may provide information that is useful for better understanding the underlying mechanisms of walking dysfunctions in MS

Kinematic Analysis of Lower Limb Joint Asymmetry during Gait in People with Multiple Sclerosis

The majority of people with Multiple Sclerosis (pwMS), report lower limb motor dysfunc- tions, which may relevantly affect postural control, gait and a wide range of activities of daily living. While it is quite common to observe a different impact of the disease on the two limbs (i.e., one of them is more affected), less clear are the effects of such asymmetry on gait performance. The present retrospective cross-sectional study aimed to characterize the magnitude of interlimb asymmetry in pwMS, particularly as regards the joint kinematics, using parameters derived from angle-angle di- agrams. To this end, we analyzed gait patterns of 101 pwMS (55 women, 46 men, mean age 46.3, average Expanded Disability Status Scale (EDSS) score 3.5, range 1–6.5) and 81 unaffected individ- uals age- and sex-matched who underwent 3D computerized gait analysis carried out using an eight-camera motion capture system. Spatio-temporal parameters and kinematics in the sagittal plane at hip, knee and ankle joints were considered for the analysis. The angular trends of left and right sides were processed to build synchronized angle–angle diagrams (cyclograms) for each joint, and symmetry was assessed by computing several geometrical features such as area, orientation and Trend Symmetry. Based on cyclogram orientation and Trend Symmetry, the results show that pwMS exhibit significantly greater asymmetry in all three joints with respect to unaffected individ- uals. In particular, orientation values were as follows: 5.1 of pwMS vs. 1.6 of unaffected individuals at hip joint, 7.0 vs. 1.5 at knee and 6.4 vs. 3.0 at ankle (p < 0.001 in all cases), while for Trend Sym- metry we obtained at hip 1.7 of pwMS vs. 0.3 of unaffected individuals, 4.2 vs. 0.5 at knee and 8.5 vs. 1.5 at ankle (p < 0.001 in all cases). Moreover, the same parameters were sensitive enough to discriminate individuals of different disability levels. With few exceptions, all the calculated sym- metry parameters were found significantly correlated with the main spatio-temporal parameters of gait and the EDSS score. In particular, large correlations were detected between Trend Symmetry and gait speed (with rho values in the range of –0.58 to –0.63 depending on the considered joint, p < 0.001) and between Trend Symmetry and EDSS score (rho = 0.62 to 0.69, p < 0.001). Such results suggest not only that MS is associated with significantly marked interlimb asymmetry during gait but also that such asymmetry worsens as the disease progresses and that it has a relevant impact on gait performances

METHODS FOR KINEMATIC ANALYSIS OF HUMAN MOVEMENT IN MILITARY APPLICATIONS: A REVIEW OF CURRENT AND PROSPECTIVE METHODS

Expansion of methods employed in the kinematic analysis of human movement for diagnosing of the physical and mental health of subjects can be traced back to the 1990`s when new information technologies and electronic recording systems started their development boom. Evaluation methods of body movement for the diagnostics of physical and mental health expanded significantly in clinical practice. This study presents an overview of these methods with the focus on how applicable the analysis of human movement can be in military practice, where they are currently marginally used. The aim of this study is to offer some recommendations on how particular methods could be utilized in an army context. This article also suggests the most appropriate methods of quantitative evaluation for posture and motion control in the course of standing, gait and other activities carried out in military training and active duty

Kinematics Adaptation and Inter-Limb Symmetry during Gait in Obese Adults

The main purpose of this study is to characterize lower limb joint kinematics during gait in obese individuals by analyzing inter-limb symmetry and angular trends of lower limb joints during walking. To this purpose, 26 obese individuals (mean age 28.5 years) and 26 normal-weight age- and sex-matched were tested using 3D gait analysis. Raw kinematic data were processed to derive joint-specific angle trends and angle-angle diagrams (synchronized cyclograms) which were characterized in terms of area, orientation and trend symmetry parameters. The results show that obese individuals exhibit a kinematic pattern which significantly differs from those of normal weight especially in the stance phase. In terms of inter-limb symmetry, higher values were found in obese individuals for all the considered parameters, even though the statistical significance was detected only in the case of trend symmetry index at ankle joint. The described alterations of gait kinematics in the obese individuals and especially the results on gait asymmetry are important, because the cyclic uneven movement repeated for hours daily can involve asymmetrical spine loading and cause lumbar pain and could be dangerous for overweight individuals

Lower Limb Kinematics in Individuals with Hip Osteoarthritis during Gait: A Focus on Adaptative Strategies and Interlimb Symmetry

Among the functional limitations associated with hip osteoarthritis (OA), the alteration of gait capabilities represents one of the most invalidating as it may seriously compromise the quality of life of the affected individual. The use of quantitative techniques for human movement analysis has been found valuable in providing accurate and objective measures of kinematics and kinetics of gait in individuals with hip OA, but few studies have reported in-depth analyses of lower limb joint kinematics during gait and, in particular, there is a scarcity of data on interlimb symmetry. Such aspects were investigated in the present study which tested 11 individuals with hip OA (mean age 68.3 years) and 11 healthy controls age- and sex-matched, using 3D computerized gait analysis to perform point-by-point comparisons of the joint angle trends of hip, knee, and ankle. Angle-angle diagrams (cyclograms) were also built to compute several parameters (i.e., cyclogram area and orientation and Trend Symmetry) from which to assess the degree of interlimb symmetry. The results show that individuals with hip OA exhibit peculiar gait patterns characterized by severe modifications of the physiologic trend at hip level even in the unaffected limb (especially during the stance phase), as well as minor (although significant) alterations at knee and ankle level. The symmetry analysis also revealed that the effect of the disease in terms of interlimb coordination is present at knee joint as well as hip, while the ankle joint appears relatively preserved from specific negative effects from this point of view. The availability of data on such kinematic adaptations may be useful in supporting the design of specific rehabilitative strategies during both preoperative and postoperative periods

Gait Control and Locomotor Recovery after Spinal Cord Injury

The gait of patients with an incomplete spinal cord injury (iSCI) has been studied previously. The most widely examined parameters to characterize iSCI gait are walking speed and time-distance measures (e.g., step length, step frequency, gait-cycle phases). In a clinical setting, the functional recovery of iSCI patients is routinely captured by specific outcome measures such as the 10-meter walk test (10mWT), the 6-minute walk test (6minWT) or the walking index for spinal cord injury (WISCI), which has been specifically established for this particular group of patients to score their walking ability. These measures are useful to monitor gross motor function and recovery during rehabilitation, but lack the ability to elucidate underlying mechanisms of gait alterations and recovery or subtle changes in locomotor pattern. In order to be able to appreciate the injury-induced deficits in locomotor control and to capture changes in motor function that may not be visible to the naked eye a sensitive and comprehensive tool is of need. The easiest way of assessing walking capacity is to collect data of walking speed and distance. Yet, one of the most obvious gait alterations in subjects with iSCI is an impaired gait quality. In the past, gait quality has been scored by trained investigators that rate defined features of walking. However, more complex movements that require precise spatial and temporal coordination of several joints and body segments are not easy to detect by mere observation. In the first study of this thesis, we evaluated the lower-limb coordination by means of combined hip-knee angular profiles (cyclograms). Patients showed distinct types and extents of cyclogram alterations and were thereupon categorized into four groups of impairment. The cyclogram seemed to reflect the underlying deficits as it correlated well with walking performance (speed) but could not be modulated with increasing speeds in contrast to a converging normalization in all control subjects. The intralimb coordination apparently is a sensitive indicator of motor-control impairment after spinal cord injury. We next evaluated a variety of gait-related parameters in order to find alterations of locomotor control after iSCI. With the aim of establishing a comprehensive framework to examine the organization of walking behavior in humans and how this organization gets distorted by insults to the spinal cord we chose a data-driven holistic approach for analyzing a multivariate set of data. This approach prevents a certain investigator-induced bias that arises when more or less arbitrarily pre-selecting a specific outcome measure. Multivariate in this case means variables of different modalities, i.e., objective electrophysiological measures that represent the integrity and electrical conductivity of specific spinal fiber tracts, kinematic measures that describe the extent of movements and body-segment coordination (i.e., gait quality) as well as measures that quantify locomotor performance such as walking speed and distance. Hence, clusters of parameters were identified that were or were not altered in iSCI patients and that were distinctly modulated with respect to speed. These findings suggest that there are distinguishable domains of neural control of walking that may be differently affected in specific neurological disorders. Consequently, the question arises as to which of these parameters change over time and what this might reveal about the mechanisms of recovery. These questions were addressed in the third study where the gait of iSCI patients was analyzed at several time points during rehabilitation in order to reveal those parameters that most strongly contribute to recovery, and also to reveal the responsiveness of the multimodal factors to an improvement in walking speed. Interestingly, the responsiveness of a single measure did not necessarily contribute to recovery, which is rather affected by the contribution of mutually interacting parameters. It remains to be elucidated where exactly the plastic changes leading to functional recovery take place and by what mechanisms they are mediated. The great challenge of spinal cord research is the cure for paralysis, or, in other words, a way to induce functional neural repair in the growth-inhibiting environment of the central nervous system (CNS). Even though it is known that spontaneous regeneration of severed neural tissue does virtually not occur in the CNS, recovery on a functional basis does happen. In the fourth study we demonstrated that the spinal cord is capable of extensive plastic changes induced by pathological processes in the absence of motor deficits and only minor sensory impairments. To accelerate the success of future clinical trials, the bridging from bench to bedside needs to be encouraged. Outcome measures should be standardized across species in order to appreciate differences and similarities. It could be shown that after a cervical hemisection of the spinal cord, equivalent to a the Brown-Séquard Syndrome in patients, humans and primates show superior recovery of function mediated by the corticospinal tract compared to rats. These findings support the importance of studies performed in primates to minimize the gap between preclinical and clinical outcome

New developments in vector coding methods for assessing coordination variability

The purpose of this study is to propose modifications to current methods for the assessment of coordination variability through vector coding techniques. Commonly, vector coding starts from calculating the vector difference between adjacent data points on an angle-angle plot. This initial stage is analogue to estimating angular velocities from displacement, but with the limitation of differentiating the three axial components in isolation. Instead, the calculation of angular velocities from 3D data should take into account movement in other planes of motion. This study suggests the use of angular velocities in vector coding in place of the difference calculations and demonstrates how using this method can be integrated with recent developments which involve the use of ellipses for calculating coordination variability of angle-angle diagrams

Biomechatronics: Harmonizing Mechatronic Systems with Human Beings

This eBook provides a comprehensive treatise on modern biomechatronic systems centred around human applications. A particular emphasis is given to exoskeleton designs for assistance and training with advanced interfaces in human-machine interaction. Some of these designs are validated with experimental results which the reader will find very informative as building-blocks for designing such systems. This eBook will be ideally suited to those researching in biomechatronic area with bio-feedback applications or those who are involved in high-end research on manmachine interfaces. This may also serve as a textbook for biomechatronic design at post-graduate level

Human Gait Model Development for Objective Analysis of Pre/Post Gait Characteristics Following Lumbar Spine Surgery

Although multiple advanced tools and methods are available for gait analysis, the gait and its related disorders are usually assessed by visual inspection in the clinical environment. This thesis aims to introduce a gait analysis system that provides an objective method for gait evaluation in clinics and overcomes the limitations of the current gait analysis systems. Early identification of foot drop, a common gait disorder, would become possible using the proposed methodology