Between-Day Reliability of the Gait Characteristics and Their Changes During the 6-Minute Walking Test in People With Multiple Sclerosis

Background: Gait characteristics and their changes during the 6-minute walking test (6MWT) in people with multiple sclerosis (pwMS) have been described in the literature, which one may refer to as walking fatigability in the body function level of the International Classification of Functioning, Disability, and Health. However, whether these metrics are reliable is unknown. Objective: To investigate the between-day reliability of the gait characteristics and their changes in pwMS and healthy controls (HCs). Methods: Forty-nine pwMS (EDSS 4.82 ± 1.22 and 54.7 ± 9.36 years) and 23 HCs (50.6 ± 6.1 years) performed the 6MWT, as fast as possible but safely while wearing Inertial Measurement Units. Gait characteristics were measured in the pace, rhythm, variability, asymmetry, kinematics, coordination, and postural control domains and were obtained in intervals of 1 minute during the 6MWT. In addition, gait characteristics change in the last minute compared with the first minute were calculated for all gait variables using a fatigability index (ie, distance walking index). The intraclass correlation coefficient (ICC), Bland-Altman Plots, and Standard error of measurement were applied to investigate reliability. Results: Reliability of gait characteristics, minute-by-minute, and for their changes (ie, using the fatigability index) ranged from poor to excellent (pwMS: ICC 0.46-0.96; HC: ICC 0.09-0.97 and pwMS: ICC 0-0.72; HC: ICC 0-0.77, respectively). Conclusion: Besides coordination, at least 1 variable of each gait domain showed an ICC of moderate or good reliability for gait characteristics changes in both pwMS and HC. These metrics can be incorporated into future clinical trials and research on walking fatigability.Clinical Trial Registration: NCT05412043

Oxygenated machine perfusion at room temperature as an alternative for static cold storage in porcine donor hearts

Background There is a continued interest in ex situ heart perfusion as an alternative strategy for donor heart preservation. We hypothesize that oxygenated machine perfusion of donor hearts at a temperature that avoids both normothermia and deep hypothermia offers adequate and safe preservation. Methods Cardioplegia-arrested porcine donor hearts were randomly assigned to six hours of preservation using cold storage (CS, n = 5) or machine perfusion using an oxygenated acellular perfusate at 21 degrees C (MP, n = 5). Subsequently, all grafts were evaluated using the Langendorff method for 120 min. Metabolic parameters and histology were analyzed. Systolic function was assessed by contractility and elastance. Diastolic function was assessed by lusitropy and stiffness. Results For both groups, in vivo baseline and post-Langendorff biopsies were comparable, as were lactate difference and myocardial oxygen consumption. Injury markers gradually increased and were comparable. Significant weight gain was seen in MP (p = 0.008). Diastolic function was not impaired in MP, and lusitropy was superior from 30 min up to 90 min of reperfusion. Contractility was superior in MP during the first hour of evaluation. Conclusion We conclude that the initial functional outcome of MP-preserved hearts was transiently superior compared to CS, with no histological injury post-Langendorff. Our machine perfusion strategy could offer feasible and safe storage of hearts prior to transplantation. Future studies are warranted for further optimization

Oxygenated machine perfusion at room temperature as an alternative for static cold storage in porcine donor hearts

Background There is a continued interest in ex situ heart perfusion as an alternative strategy for donor heart preservation. We hypothesize that oxygenated machine perfusion of donor hearts at a temperature that avoids both normothermia and deep hypothermia offers adequate and safe preservation. Methods Cardioplegia-arrested porcine donor hearts were randomly assigned to six hours of preservation using cold storage (CS, n = 5) or machine perfusion using an oxygenated acellular perfusate at 21 degrees C (MP, n = 5). Subsequently, all grafts were evaluated using the Langendorff method for 120 min. Metabolic parameters and histology were analyzed. Systolic function was assessed by contractility and elastance. Diastolic function was assessed by lusitropy and stiffness. Results For both groups, in vivo baseline and post-Langendorff biopsies were comparable, as were lactate difference and myocardial oxygen consumption. Injury markers gradually increased and were comparable. Significant weight gain was seen in MP (p = 0.008). Diastolic function was not impaired in MP, and lusitropy was superior from 30 min up to 90 min of reperfusion. Contractility was superior in MP during the first hour of evaluation. Conclusion We conclude that the initial functional outcome of MP-preserved hearts was transiently superior compared to CS, with no histological injury post-Langendorff. Our machine perfusion strategy could offer feasible and safe storage of hearts prior to transplantation. Future studies are warranted for further optimization.</p

Neural Basis of Interlimb Coordination during Walking in Children

People swing their arms unconsciously in a reciprocal manner during walking. This feature seems quite useless for locomotion at first sight. After all, people are able to walk without the arms swinging, or when the arms are making other (complex) movements (such as waving the arms or juggling). Even though the arm movements are unnecessary to walk, they do have some beneficial effects on the walking pattern. For instance, when the arms are swinging during walking, less energy is consumed compared to when they are not swinging. This positive effect of arm swinging on gait, however, does not explain what causes people to swing their arms without having to think about them. Therefore, in the current doctoral thesis, we wanted to gain more insight in the neural basis of the natural reciprocal arm swing. It is described in literature that arm muscle activation may come about by the way the nervous system is built, with interconnected Central Pattern Generators (CPGs) generating locomotion patterns. It is suggested that bipedal and quadrupedal locomotion share common spinal neuronal control mechanisms, which is based on the assumption that during evolution, man started to walk bipedally, and the circuitry, previously used for the arms during locomotion, remained operational. These CPGs generating locomotion patterns are located in the spinal cord, where they are interconnected and controlled by brainstem and cortical circuits. Some authors, however, have emphasized the direct control from the cortex. If arm swinging during gait would primarily originate from cortical contributions, one would expect this to be reflected in deteriorated or altered arm swing in persons with a cortical deficit. To this end, the studies in the current doctoral thesis have focused on children with spastic hemiplegic and diplegic Cerebral Palsy. These are the two most common types of Cerebral Palsy (CP), in which non-progressive impairment to the brain resulted in abnormal limb strength, control, and/or muscle tone. In children with hemiplegia, one side of the body is more affected than the other, while in children with diplegia the lower extremities are more affected than the upper extremities. In children with CP, systematic studies about the arm movements during walking are very scarce. Therefore in the first phase of the current doctoral thesis, different aspects of the arm behavior during walking in these children were examined.The different aspects under investigation were arm swing amplitude, arm posture, and the interlimb coordination. We found that, overall, children with CP moved their arms differently during walking and this was reflected in all three evaluated aspects. In particular, children with CP were unable to further increase their arm swing amplitude to the same extent as typically developing (TD) children when walking faster. Moreover, children with hemiplegia specifically showed increased arm swing on the non-hemiplegic side and decreased arm swing on the hemiplegic side. With respect to arm posture, both CP groups presented withand altered posture on both sides of the body. They held their hands higher and more in front of the body with their upper arm was rotated more to the posterior. Again, children with hemiplegia showed a clear asymmetry. Their hemiplegic arm was held in an even higher position. As expected, these alterations in arm swing and posture affected interlimb coordination during walking as well. Specifically, in children with hemiplegia, the hemiplegic arm impaired coordinative stability and constrained the synchronization of the limbs. In contrast, in children with diplegia, the legs limited the ability to coordinate the limb pairs, but it were the arms that affected coordinative stability.Overall these alterations and deficits seemed to be related to secondary causes, such as spasticity, muscle weakness, and compensations (for stability or angular momentum), rather than they are directly related to the primary cortical deficit. Thus, this newly obtained knowledge is crucial in order to know which aspect of the arm behavior should or should not be adapted in order to improve the overall walking pattern of a patient with CP.From the experiments of phase one, it already appeared that arm swing does not entirely depend on cortical control because, despite the difference between children with CP and TD children, the basic pattern was maintained. In the second phase of the current doctoral thesis we further explored the role of the cortex in the neural basis of the arm movements during gait. To this end, we used the forward walking (FW) and backward walking (BW). This paradigm allowed us to infer about the similarity in the neural mechanisms controlling the limbs for the different directions of walking. This has been done in earlier studies for the leg kinematics, which were found to be similar between FW and BW reversed in time, but this has not been done for the arm kinematics. Hence, this led us to investigate whether, as for leg movements during walking, the kinematical patterns of the arm movements during FW and BW would be equivalent but reversed in time. The results, indeed, demonstrated this similarity in healthy participants (i.e. TD children), and supported the idea that the neural control of the locomotor arm movements is organized in a similar way as for the leg movements. Further, in order to differentiate whether the neural control of locomotor limb movements primarily arises from a cortical source or from peripherally located networks, we determined whether an intact cortex is needed to sustain the simple kinematical reversal from FW to BW. To this end, we investigated whether in children with CP the same kinematical reversal for the arm and leg movements took place from FW to BW as in TD children. It turned out that also in children with CP the degree of similarity between the limb kinematics of FW and BW was considerable, which indicated that the neural mechanism of interlimb coordination during walking does not depend mainly on a cortical source.In summary, the above described findings have mapped the uncharted impairments of arm behavior (i.e. arm swing, arm posture and interlimb coordination deficits) arising during walking in children with CP. This knowledge can be used to aid in gait rehabilitation when attempting to implement arm movements in gait training programs. Furthermore, fundamental knowledge is gained about the possible causes (i.e. spasticity, muscle tone, compensation strategy) of the altered arm behavior in children with CP. Studying the arm behavior during FW and BW allowed us to acquire further insights in the neural mechanisms controlling locomotor arm movements (i.e. the neural mechanisms for the lower and upper limbs are organized in a similar manner). Furthermore, comparing the results of TD children with children with CP, increased our understanding where the neural control of locomotor limb movements predominantly originates from (i.e. from sites more peripherally located than the cortex such as the brain stem or the spinal cord). The insights provided by the current doctoral thesis have opened the way for further research on the implementation of arm movements in the gait rehabilitation in children with CP and on the relative contribution of the different neural areas/networks in control of locomotor limb movements.nrpages: 223status: publishe

Is action-perception coupling improved with delay in patients with focal cerebellar lesions?

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Restricted arm swing affects gait stability and increased walking speed alters trunk movements in children with cerebral palsy

Observational research suggests that in children with cerebral palsy, the altered arm swing is linked to instability during walking. Therefore, the current study investigates whether children with cerebral palsy use their arms more than typically developing children, to enhance gait stability. Evidence also suggests an influence of walking speed on gait stability. Moreover, previous research highlighted a link between walking speed and arm swing. Hence, the experiment aimed to explore differences between typically developing children and children with cerebral palsy taking into account the combined influence of restricting arm swing and increasing walking speed on gait stability. Spatiotemporal gait characteristics, trunk movement parameters and margins of stability were obtained using three dimensional gait analysis to assess gait stability of 26 children with cerebral palsy and 24 typically developing children. Four walking conditions were evaluated: (i) free arm swing and preferred walking speed; (ii) restricted arm swing and preferred walking speed; (iii) free arm swing and high walking speed; and (iv) restricted arm swing and high walking speed. Double support time and trunk acceleration variability increased more when arm swing was restricted in children with bilateral cerebral palsy compared to typically developing children and children with unilateral cerebral palsy. Trunk sway velocity increased more when walking speed was increased in children with unilateral cerebral palsy compared to children with bilateral cerebral palsy and typically developing children and in children with bilateral cerebral palsy compared to typically developing children. Trunk sway velocity increased more when both arm swing was restricted and walking speed was increased in children with bilateral cerebral palsy compared to typically developing children. It is proposed that facilitating arm swing during gait rehabilitation can improve gait stability and decrease trunk movements in children with cerebral palsy. The current results thereby partly support the suggestion that facilitating arm swing in specific situations possibly enhances safety and reduces the risk of falling in children with cerebral palsy.status: publishe

Restricted arm swing affects gait stability and increased walking speed alters trunk movements in children with cerebral palsy

Observational research suggests that in children with cerebral palsy, the altered arm swing is linked to instability during walking. Therefore, the current study investigates whether children with cerebral palsy use their arms more than typically developing children, to enhance gait stability. Evidence also suggests an influence of walking speed on gait stability. Moreover, previous research highlighted a link between walking speed and arm swing. Hence, the experiment aimed to explore differences between typically developing children and children with cerebral palsy taking into account the combined influence of restricting arm swing and increasing walking speed on gait stability.Spatiotemporal gait characteristics, trunk movement parameters and margins of stability were obtained using three dimensional gait analysis to assess gait stability of 26 children with cerebral palsy and 24 typically developing children. Four walking conditions were evaluated: (i) free arm swing & preferred walking speed; (ii) restricted arm swing & preferred walking speed; (iii) free arm swing & high walking speed; (iv) restricted arm swing & high walking speed.Double support time and trunk acceleration variability increased more when arm swing was restricted in children with bilateral cerebral palsy compared to typically developing children and children with unilateral cerebral palsy. Trunk sway velocity increased more when walking speed was increased in children with unilateral cerebral palsy compared to children with bilateral cerebral palsy and typically developing children and in children with bilateral cerebral palsy compared to typically developing children. Trunk sway velocity increased more when both arm swing was restricted and walking speed was increased in children with bilateral cerebral palsy compared to typically developing children.It is proposed that facilitating arm swing during gait rehabilitation can improve gait stability and decrease trunk movements in children with cerebral palsy. The current results thereby partly support the suggestion that facilitating arm swing in specific situations possibly enhances safety and reduces the risk of falling in children with cerebral palsy

Interlimb coordination during forward walking is largely preserved in backward walking in children with Cerebral Palsy

OBJECTIVE: Limb kinematics in backward walking (BW) are essentially those of forward walking (FW) in reverse. It has been argued that subcortical mechanisms could underlie both walking modes. METHODS: Therefore, we tested whether participants with supraspinal/cortical deficits (i.e. cerebral palsy) show the kinematic reversal from FW to BW. 3D gait analysis was performed in 15 children with diplegia and 11 children with hemiplegia to record elevation angles of upper arm, lower arm, upper leg, lower leg, and foot, and were compared to those of 23 control subjects. Coordination patterns were compared between FW and BW, and elevation angle traces of BW were reversed in time (revBW) and correlated to FW traces. RESULTS: The interlimb coordination pattern during BW was largely preserved for all groups. The kinematic reversal of the limbs was also present in children with cerebral palsy (represented by high correlation coefficients between FW and revBW kinematics). CONCLUSIONS: The neural control mechanism of FW leading to BW, is preserved in persons with cortical deficits (as in cerebral palsy). SIGNIFICANCE: The current results support previous evidence suggesting that interlimb locomotor coordination depends mostly on the coupling between spinal pattern generators, coordinated by brainstem mechanisms, rather than primarily on cortical structures.publisher: Elsevier articletitle: Interlimb coordination during forward walking is largely preserved in backward walking in children with cerebral palsy journaltitle: Clinical Neurophysiology articlelink: http://dx.doi.org/10.1016/j.clinph.2013.08.022 content_type: article copyright: Copyright © 2013 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.status: publishe