Objective assessment of motor fatigue in multiple sclerosis using kinematic gait analysis: a pilot study

<p>Abstract</p> <p>Background</p> <p>Fatigue is a frequent and serious symptom in patients with Multiple Sclerosis (MS). However, to date there are only few methods for the objective assessment of fatigue. The aim of this study was to develop a method for the objective assessment of motor fatigue using kinematic gait analysis based on treadmill walking and an infrared-guided system.</p> <p>Patients and methods</p> <p>Fourteen patients with clinically definite MS participated in this study. Fatigue was defined according to the Fatigue Scale for Motor and Cognition (FSMC). Patients underwent a physical exertion test involving walking at their pre-determined patient-specific preferred walking speed until they reached complete exhaustion. Gait was recorded using a video camera, a three line-scanning camera system with 11 infrared sensors. Step length, width and height, maximum circumduction with the right and left leg, maximum knee flexion angle of the right and left leg, and trunk sway were measured and compared using paired t-tests (α = 0.005). In addition, variability in these parameters during one-minute intervals was examined. The fatigue index was defined as the number of significant mean and SD changes from the beginning to the end of the exertion test relative to the total number of gait kinematic parameters.</p> <p>Results</p> <p>Clearly, for some patients the mean gait parameters were more affected than the variability of their movements while other patients had smaller differences in mean gait parameters with greater increases in variability. Finally, for other patients gait changes with physical exertion manifested both in changes in mean gait parameters and in altered variability. The variability and fatigue indices correlated significantly with the motoric but not with the cognitive dimension of the FSMC score (R = -0.602 and R = -0.592, respectively; P < 0.026).</p> <p>Conclusions</p> <p>Changes in gait patterns following a physical exertion test in patients with MS suffering from motor fatigue can be measured objectively. These changes in gait patterns can be described using the motor fatigue index and represent an objective measure to assess motor fatigue in MS patients. The results of this study have important implications for the assessments and treatment evaluations of fatigue in MS.</p

Prolonged Quadriceps Activity Following Imposed Hip Extension: A Neurophysiological Mechanism for Stiff-Knee Gait?

The biomechanical characteristics of stiff knee gait following neurological injury include decreased knee flexion velocity at toe-off, which may be due to exaggerated quadriceps activity. The neuromuscular mechanism underlying this abnormal activity is unclear, although hyperexcitable heteronymous reflexes may be a source of impaired coordination. The present study examines the contribution of reflex activity from hip flexors on knee extensors following stroke and its association with reduced swing-phase knee flexion during walking. Twelve individuals poststroke and six control subjects were positioned in supine on a Biodex dynamometer with the ankle and knee held in a static position. Isolated hip extension movements were imposed at 60, 90, and 120°/s through a 50° excursion to end-range hip extension. Reflexive responses of the rectus femoris (RF), vastus lateralis (VL), and vastus medialis (VM) were quantified during and after the imposed hip rotation. Gait analysis was also performed for all subjects in the stroke group. In subjects with stroke, imposed hip extension evoked a brief reflexive response in the quadriceps, followed by a heightened level of sustained activity. The initial response was velocity dependent and was larger in the stroke group than in the control group. In contrast, the prolonged response was not velocity dependent, was significantly greater in the VL and RF in subjects with stroke, and, importantly, was correlated to decreased swing-phase knee flexion. Hyperexcitable heteronymous connections from hip flexors to knee extensors appear to elicit prolonged quadriceps activity and may contribute to altered swing-phase knee kinematics following stroke

The effect of dynamic ankle-foot orthoses on the balance and gait of stroke patients

The present research aimed to assess the effects of a novel type of orthosis, the Dynamic Ankle Foot Orthosis (DAFO), on the balance and gait characteristics of hemiparetic subjects. The DAFO is a low splint with a custom-moulded insole, which is believed to support foot alignment, ankle supination-pronation and provide minimal restriction of the ankle joint flexion-extension. It was hypothesised that DAFOs improve motor behaviour after stroke involving the acquisition of standing balance (hypothesis I) and gait (hypothesis II) compared with using shoes. It was proposed that users' subjective opinions of DAFOs would support the findings of the device's ability to modify human performance such that they are beneficial when used as a part of rehabilitation management for stroke patients (hypothesis III). Twenty-two stroke subjects were randomly allocated to experimental (with DAFO and shoes-only) and control (using shoes-only) groups. Subjects followed twelve weeks of experimental trials comprising three data collections. The testing procedure was developed from preliminary work, which involved a pilot study and reliability tests. Standing balance was measured using forceplatform apparatus. The parameters investigated were: the velocity and sway index of the CoP, and F(mean), F(sd) and F(slope) of shear forces. Kinematic gait performance was assessed using a 3-D four-camera motion measurement system. The parameters studied were: the gait velocity, stride length, step length, cadence, and single stance phase, together with the minimum/maximum values of the angular displacement and velocity of the foot, shank, and thigh segments in the saggittal plane during two strides. An open questionnaire was used to evaluate subjects' opinions regarding the use of DAFOs. Overall, the quantitative studies did not identify consistent and statistically significant differences between the two experimental situations for these groups of patients. In the studies of balance, none of the parameter comparisons analysed within- and between- groups achieved statistical significance. In the studies of gait, statistically significant differences were identified for some (but not all) parameters. It is unknown whether any single or combination of balance and gait variables can be used to describe human gait entirely. On this basis, hypotheses I and II were rejected. However, these are tentative conclusions. Thus, difficulties in maintaining the stroke subject cohort number for these studies meant that the analyses probably lacked sufficient statistical power to detect small but potentially important differences in DAFO mediated actions. Furthermore, in several cases, clear differences in the magnitude of balance and gait parameters between DAFO and shoe users were apparent, and these differences were often consistent with nearer normal levels associated with use of the device (suggesting potentially beneficial influences). Thus, positive effects of the DAFO on lateral velocity of sway and variability of the spectral frequency were evident for some subjects. The gait velocity, stride length and single stance phase were also nearer normal values using DAFOs than without them. In addition, the maximum foot velocity value was improved in the middle of swing phase on the affected side, which may indicate improvement to the ankle dorsiflexion function using these devices. In contrast to the inconclusive balance and gait findings, the outcome of the questionnaire assessments was clear. The majority of subjects provided very positive feedback with regard to DAFO use. Most subjects expressed confidence in the splint, which they perceived as helpful for their walking ability in day life. Some difficulties were noticed with donning and doffing the DAFO, but the perceived benefits outweighed this consideration. These qualitative studies therefore provide the most convincing evidence to support the idea that DAFOs improve stroke patients' balance and gait, and that this type of orthosis may form a useful adjunct to rehabilitation strategies. However, as the proposals set out for this research were related, acceptance of hypothesis III requires that at least one of the preceding hypotheses be accepted. On this basis, hypothesis III was also rejected. In conclusion, although this work failed overall to demonstrate a significant effect of DAFOs on the rehabilitation of stroke patients, the anecdotal evidence obtained adds to knowledge in this field. The research identified some parameters of balance and gait, which might be influenced by the device in a beneficial manner. These parameters may be more useful to use in future investigations. The reasons for the discrepant outcomes of the quantitative and qualitative studies are unclear. However, it is suggested that there may be uncontrolled variables within either the patient group or in the DAFOs (or both) which mean that some DAFOs work better than others. It is proposed that further studies of the DAFO are warranted.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Quantitative Characterization of Gait Patterns in Individuals with Spinocerebellar Ataxia 38

Spinocerebellar ataxia 38 (SCA 38) is a rare autosomal neurological disease whose clinical features include, among others, severe gait disturbances that have not yet been fully characterized. In this study, we employed a computerized 3D gait analysis to obtain spatio-temporal parameters of gait and the kinematics in the sagittal plane in the hip, knee, and ankle joints of seven individuals with SCA 38, which were then compared with those of twenty unaffected individuals matched for age, sex, and anthropometric features. The results show that, in comparison with unaffected individuals, those with SCA 38 are characterized by a significantly reduced speed, stride length, and duration of the swing phase, as well as an increased step width and stance and double support phase durations. The point-by-point comparison of the angular trends at the hip, knee, and ankle joints revealed significant alterations during most part of the stance phase for hip joint and at pre-swing/swing phases for knee and ankle joints. For these latter joints, a significantly reduced dynamic range of motion was also found. Such findings provide some new insights into hip and knee kinematics for this specific form of ataxia and may be useful for monitoring the disease’s progression and designing specific, tailored rehabilitative interventions

The sooner the better?!:Providing ankle-foot orthoses in the rehabilitation after stroke

In stroke, the blood circulation in the brain is affected, being either ischemic or hemorrhagic. Depending on the location of the lesion, the effects can widely vary. Initial walking function is limited in approximately two-third of the patients. A “drop-foot”, the inability to dorsiflex the foot, is estimated to be present in 20-30% of the people after stroke and causes foot-clearance problems during swing phase and also affects initial contact at the start of the stance phase. Insufficient foot-clearance is associated with high risks for stumbling and falling. Ankle-foot orthoses (AFOs) are commonly used to correct drop-foot after stroke and are reported to improve mobility and balance, ankle kinematics, walking speed, self-confidence and fear of falling after stroke. However, most studies reporting on AFOs after stroke included chronic stroke patients who were already provided with AFOs in daily life and were able to walk independently. The general aim of this thesis was to increase the understanding of the effects of providing AFOs early after stroke. The EVOLUTIONS-project was conducted, including a randomized controlled trial in which the effects of AFO-provision on two different time points in the rehabilitation after stroke were studied. Subjects were included within six weeks after stroke and randomized for AFO-provision at inclusion of the study (in week 1) or eight weeks later (in week 9). The subjects were provided with one of three commonly used types of off-the-shelf, non-articulated AFOs with variability in stiffness. Subjects randomized for delayed provision did not use an AFO in the first eight weeks of the study. Subjects were studied up to 17 weeks with (bi)weekly intervals. Follow-up measurements up to 26 and 52 weeks were included. Measurements included functional outcomes related to balance, walking and activities of daily life. Furthermore, gait kinematics of the affected lower limb, muscle activation patterns of the tibialis anterior muscle, and falls and near falls were studied. Results showed positive effects on functional outcomes, both when AFOs were provided early or delayed. After 26 weeks no differences in functional outcomes were found between both groups. However, the results suggest that early provision results in better outcomes in the first 11-13 weeks of the study. Ankle dorsiflexion significantly improved directly after AFO-provision, changing the ankle from a plantarflexion into a dorsiflexion angle at initial contact, foot-off and during swing. These results were obtained regardless of AFO-provision early or delayed after stroke. In general, knee, hip and pelvis angles did not change directly after AFO-provision. After 26 weeks, no differences in kinematics in any of the joint angles were found between the two groups. These kinematic results indicate that AFOs improved drop-foot, but did not influence movement patterns around pelvis and hip. Previous literature suggested that AFO-use might increase muscle weakness, and thereby could impede recovery. Therefore, the effects of AFO-provision on muscle activity of the tibialis anterior were assessed. Results showed that AFO-use reduced muscle activity during swing within a measurement session, compared to walking without AFO. However, 26 weeks use of an AFO did not affect tibialis anterior muscle activity during walking without AFO. Again, early or delayed AFO-provision did not affect the results. These results indicate that there is no need to fear negative consequences on tibialis anterior activity because of long-term AFO-use (early) after stroke. In addition, the effects on the occurrence and circumstances of (near) falls were studied using diaries. In case of an incident, the location, performed activity, possible injuries and whether the AFO was used. We found that subjects in the early group, who had already been provided with AFOs, fell significantly more often in the first eight weeks of the study, compared to the delayed group who had not yet been provided with AFOs. The majority of the falls in the early group in week 1-8 occurred without wearing the AFO. Falls mainly occurred during transfers and standing, during activities related to getting in/out bed, toileting and showering. The majority of the subjects had not yet reached an independent ambulation level at the time of the fall (Functional Ambulation Categories ≤3) and had low balance levels (Berg Balance Scale <45). This highlights the need for careful instructions from clinicians and nursing staff to patients and their relatives, and to emphasize the potential risks of performing activities without the proper assistance, especially in situations without wearing the AFO and without independent walking ability. Summarizing, the results of the current thesis show that clinicians, together with the patient, can decide what they value most in when making the decision on when to commence with AFO-provision. AFOs were found to improve drop-foot regardless of the timing of AFO-provision after stroke. Early AFO-use is expected to result in higher functional levels earlier in the rehabilitation. Despite potential functional gains in the first period of rehabilitation, early AFO-provision does not lead to higher functional levels after 26 weeks, compared to delayed provision. In addition, early or delayed AFO-provision did not influence pelvis, hip and knee kinematics on the short- or long-term. Therefore, AFOs should be provided to correct the drop-foot, but there is no reason to assume that early AFO-provision will influence the development of compensatory movements around the pelvis and hip in the rehabilitation after stroke. AFO-use reduced muscle activity of the tibialis anterior in swing compared to walking without AFO, when effects were measured within one measurement session. However, no negative effects over 26-weeks were found. Therefore, based on the results of our study, fear of disuse concerning the tibialis anterior does not seem to be a justifiable reason to delay AFO-use in the rehabilitation after stroke. One should be aware that higher numbers of falls were found in case that subjects were provided with AFOs early after stroke. Special attention needs to be made to the specific instructions given regarding AFO-use, since the majority of the falls occurred without wearing the AFO and while subjects were not allowed to ambulate independently

Knee Joint Dysfunctions That Influence Gait in Cerebrovascular Injury

INTRODUCTION: There is still no consensus among different specialists on the subject of kinematic variation during the hemiparetic gait, including the main changes that take place during the gait cycle and whether the gait velocity changes the patterns of joint mobility. One of the most frequently discussed joints is the knee. OBJECTIVES: This study aims to evaluate the variables found in the angular kinematics of knee joint, and to describe the alterations found in the hemiparetic gait resulting from cerebrovascular injury. METHODS: This study included 66 adult patients of both genders with a diagnosis of either right or left hemiparesis resulting from ischemic cerebrovascular injury. All the participants underwent three-dimensional gait evaluation, an the angular kinematics of the joint knee were selected for analysis. RESULTS: The results were distributed into four groups formed based on the median of the gait speed and the side of hemiparesis. CONCLUSIONS: The relevant clinical characteristics included the important mechanisms of loading response in the stance, knee hyperextension in single stance, and reduction of the peak flexion and movement amplitude of the knee in the swing phase. These mechanisms should be taken into account when choosing the best treatment. We believe that the findings presented here may aid in preventing the occurrence of the problems found, and also in identifying the origin of these problems

Functional Comparison of Conventional AFOs with the Dynamic Response AFO

Ankle foot orthoses (AFOs) are commonly prescribed to provide stability and foot clearance for patients with weakened or injured musculature. The Dynamic Response AFO (DRAFO) was designed to improve proprioception at heel strike. The design includes a rigid outer shell with a cut out heel and a soft inner lining; it is typically aligned in plantarflexion and may incorporate external heel wedges. The objective of this study was to investigate the effects of the DRAFO design features and contrast its biomechanical function with that of conventional locked and articulating AFOs. The research hypotheses were: 1) DRAFO-assisted gait parameters (e.g. ankle plantarflexion during early stance, cross-over times of the shank and thigh vertical angles during stance, step width, dorsi activity duration during stance, and center of pressure progression during loading response) will approximate the no AFO condition and 2) DRAFO-assisted gait parameters (e.g. ankle and knee kinematics, cross-over times of the shank and thigh vertical angles during stance, peak foot progression angle, step width, stance phase dorsiflexion activity duration, and mediolateral motion of the center of pressure) will differ from the locked and articulating AFOs. Ten young healthy subjects were recruited for gait analyses during level treadmill walking; four AFO conditions were contrasted. After five minutes of AFO and treadmill acclimation, each subject walked for two minutes at the self-selected walking speed on a level treadmill. Acquired data included lower extremity joint and segment kinematics, dorsiflexion and plantarflexion muscle activity, and treadmill kinetic data. Ambulation in the DRAFO demonstrated significantly greater knee flexion and ankle plantarflexion than with conventional AFOs, the foot progression angle was reduced in the DRAFO relative to the no AFO condition, the center of pressure progression for the DRAFO was more medial than that observed during the no and articulating AFO conditions, and the time to transition from an inclined to a reclined shank during swing was delayed. These findings suggest that the plantarflexed alignment, external heel wedges, and perhaps the soft heel features of the DRAFO design affect lower limb joint and segment kinematics, while the rigid structure provides stability to the ankle and subtalar joints

Knee joint dysfunctions that influence gait in cerebrovascular injury

INTRODUCTION: There is still no consensus among different specialists on the subject of kinematic variation during the hemiparetic gait, including the main changes that take place during the gait cycle and whether the gait velocity changes the patterns of joint mobility. One of the most frequently discussed joints is the knee. OBJECTIVES: This study aims to evaluate the variables found in the angular kinematics of knee joint, and to describe the alterations found in the hemiparetic gait resulting from cerebrovascular injury. METHODS: This study included 66 adult patients of both genders with a diagnosis of either right or left hemiparesis resulting from ischemic cerebrovascular injury. All the participants underwent three-dimensional gait evaluation, an the angular kinematics of the joint knee were selected for analysis. RESULTS: The results were distributed into four groups formed based on the median of the gait speed and the side of hemiparesis. CONCLUSIONS: The relevant clinical characteristics included the important mechanisms of loading response in the stance, knee hyperextension in single stance, and reduction of the peak flexion and movement amplitude of the knee in the swing phase. These mechanisms should be taken into account when choosing the best treatment. We believe that the findings presented here may aid in preventing the occurrence of the problems found, and also in identifying the origin of these problems

Multi-Site Identification and Generalization of Clusters of Walking Behaviors in Individuals With Chronic Stroke and Neurotypical Controls

Background Walking patterns in stroke survivors are highly heterogeneous, which poses a challenge in systematizing treatment prescriptions for walking rehabilitation interventions. Objectives We used bilateral spatiotemporal and force data during walking to create a multi-site research sample to: (1) identify clusters of walking behaviors in people post-stroke and neurotypical controls and (2) determine the generalizability of these walking clusters across different research sites. We hypothesized that participants post-stroke will have different walking impairments resulting in different clusters of walking behaviors, which are also different from control participants. Methods We gathered data from 81 post-stroke participants across 4 research sites and collected data from 31 control participants. Using sparse K-means clustering, we identified walking clusters based on 17 spatiotemporal and force variables. We analyzed the biomechanical features within each cluster to characterize cluster-specific walking behaviors. We also assessed the generalizability of the clusters using a leave-one-out approach. Results We identified 4 stroke clusters: a fast and asymmetric cluster, a moderate speed and asymmetric cluster, a slow cluster with frontal plane force asymmetries, and a slow and symmetric cluster. We also identified a moderate speed and symmetric gait cluster composed of controls and participants post-stroke. The moderate speed and asymmetric stroke cluster did not generalize across sites. Conclusions Although post-stroke walking patterns are heterogenous, these patterns can be systematically classified into distinct clusters based on spatiotemporal and force data. Future interventions could target the key features that characterize each cluster to increase the efficacy of interventions to improve mobility in people post-stroke