Split-arm swinging: the effect of arm swinging manipulation on interlimb coordination during walking

Abnormal arm swing movements in Parkinson's disease: onset, progression and response to L-Dopa

BACKGROUND

Reduced arm swing movements during gait are an early motor manifestation of Parkinson's disease (PD). The clinical evolution, response to L-Dopa and pathophysiological underpinning of abnormal arm swing movements in PD remain largely unclear. By using a network of wearable sensors, this study objectively assesses arm swing movements during gait in PD patients across different disease stages and therapeutic conditions.

METHODS

Twenty healthy subjects (HS) and 40 PD patients, including 20 early-stage and 20 mid-advanced subjects, underwent a 6-m Timed Up and Go test while monitored through a network of wearable inertial sensors. Arm swing movements were objectively evaluated in both hemibodies and different upper limb joints (shoulder and elbow), using specific time-domain (range of motion and velocity) and frequency-domain measures (harmonics and total harmonic distortion). To assess the effects of L-Dopa, patients under chronic dopaminergic therapy were randomly examined when OFF and ON therapy. Finally, clinical-behavioral correlations were investigated, primarily focusing on the relationship between arm swing movements and cardinal L-Dopa-responsive motor signs, including bradykinesia and rigidity.

RESULTS

Compared to HS, the whole group of PD patients showed reduced range of motion and velocity, alongside increased asymmetry of arm swing movements during gait. Additionally, a distinct increase in total harmonic distortion was found in patients. The kinematic changes were prominent in the early stage of the disease and progressively worsened owing to the involvement of the less affected hemibody. The time- and frequency-domain abnormalities were comparable in the two joints (i.e., shoulder and elbow). In the subgroup of patients under chronic dopaminergic treatment, L-Dopa restored patterns of arm swing movements. Finally, the kinematic alterations in arm swing movements during gait correlated with the clinical severity of bradykinesia and rigidity.

CONCLUSIONS

Arm swing movements during gait in PD are characterized by narrow, slow, and irregular patterns. As the disease progresses, arm swing movements deteriorate also in the less affected hemibody, without any joint specificity. The positive response to L-Dopa along with the significant correlation between kinematics and bradykinesia/rigidity scores points to the involvement of dopaminergic pathways in the pathophysiology of abnormal arm swing movements in PD.

Differential gait adaptation patterns in Parkinson's disease - a split belt treadmill pilot study

BACKGROUND

Interventions using split belt treadmills (SBTM) aim to improve gait symmetry (GA) in Parkinson's disease (PD). Comparative effects in conjugated SBTM conditions were not studied systematically despite potentially affecting intervention outcomes. We compared gait adaptation effects instigated by SBTM walking with respect to the type (increased\decreased speed) and the side (more/less affected) of the manipulated belt in PD.

METHODS

Eight individuals with PD performed four trials of SBTM walking, each consisted of baseline tied belt configuration, followed by split belt setting - either WS or BS belt's speed increased or decreased by 50% from baseline, and final tied belt configuration. Based on the disease's motor symptoms, a 'worst' side (WS) and a 'best' side (BS) were defined for each participant.

RESULTS

SB initial change in GA was significant regardless of condition (p ≤ 0.02). This change was however more pronounced for BS-decrease compared with its matching condition WS-increase (p = 0.016). Similarly, the same was observed for WS-decrease compared to BS-increase (p = 0.013). Upon returning to tied belt condition, both BS-decrease and WS-increased resulted in a significant change in GA (p = 0.04). Upper limb asymmetry followed a similar trend of GA reversal, although non-significant.

CONCLUSIONS

Stronger effects on GA were obtained by decreasing the BS belt's speed of the best side, rather than increasing the speed of the worst side. Albeit a small sample size, which limits the generalisability of these results, we propose that future clinical studies would benefit from considering such methodological planning of SBTM intervention, for maximising of intervention outcomes. Larger samples may reveal arm swinging asymmetries alterations to match SBTM adaptation patterns. Finally, further research is warranted to study post-adaption effects in order to define optimal adaptation schemes to maximise the therapeutic effect of SBTM based interventions.

Design of a Bio-Inspired Gait Phase Decoder Based on Temporal Convolution Network Architecture With Contralateral Surface Electromyography Toward Hip Prosthesis Control

Inter-leg coordination is of great importance to guarantee the safety of the prostheses wearers, especially for the subjects at high amputation levels. The mainstream of current controllers for lower-limb prostheses is based on the next motion state estimation by the past motion signals at the prosthetic side, which lacks immediate responses and increases falling risks. A bio-inspired gait pattern generation architecture was proposed to provide a possible solution to the bilateral coordination issue. The artificial movement pattern generator (MPG) based on the temporal convolution network, fusing with the motion intention decoded from the surface electromyography (sEMG) measured at the impaired leg and the motion status from the kinematic modality of the prosthetic leg, can predict four sub gait phases. Experiment results suggested that the gait phase decoder exhibited a relatively high intra-subject consistency in the gait phase inference, adapted to various walking speeds with mean decoding accuracy ranging from 89.27 to 91.16% across subjects, and achieved an accuracy of 90.30% in estimating the gait phase of the prosthetic leg in the hip disarticulation amputee at the self-selected pace. With the proof of concept and the offline experiment results, the proposed architecture improves the walking coordination with prostheses for the amputees at hip level amputation.

Effect of Unilateral Shoulder Disorder on the Stance Phase of Human Gait

Background. Gait analysis systems serve as important tools for assessing disturbed gait patterns. Amongst other factors, functional limitations of the shoulder joint may relate to such disturbances. Patient-reported outcome measures, assessment of pain, and active range of motion are commonly used to describe shoulder impairment. Purpose. The aim of this cohort study was to evaluate the impact of unilateral limitations of shoulder mobility and pain on gait patterns and to detect correlations between pain, shoulder mobility, and particular phases of human gait using a Zebris gait analysis system. Methods. 20 subjects with unilaterally restricted mobility and pain of the affected shoulder and a control group of 10 healthy subjects underwent a gait analysis. Various gait parameters, the DASH score, pain at rest and movement of the affected shoulder, and the active range of motion (aROM) for shoulder flexion and abduction were recorded. Results. We determined significant differences of the duration of the loading response ( $p$  = 0.021), midstance ( $p$  = 0.033), and the terminal stance phase ( $p$  = 0.019) between the shoulder group and the control group, with a shorter loading response phase and a longer terminal stance phase of the affected side in the shoulder group. In the shoulder group, we found significant correlations between the DASH and the duration of the midstance phase ( $p$  = 0.023) and the terminal stance phase ( $p$  = 0.038). In addition, there was a significant correlation between shoulder flexion and the duration of the midstance phase ( $p$  = 0.047).

Walking on Mild Slopes and Altering Arm Swing Each Induce Specific Strategies in Healthy Young Adults

Slopes are present in everyday environments and require specific postural strategies for successful navigation; different arm strategies may be used to manage external perturbations while walking. It has yet to be determined what impact arm swing has on postural strategies and gait stability during sloped walking. We investigated the potentially interacting effects of surface slope and arm motion on gait stability and postural strategies in healthy young adults. We tested 15 healthy adults, using the CAREN-Extended system to simulate a rolling-hills environment which imparted both incline (uphill) and decline (downhill) slopes (± 3°). This protocol was completed under three imposed arm swing conditions: held, normal, active. Spatiotemporal gait parameters, mediolateral margin of stability, and postural kinematics in anteroposterior (AP), mediolateral (ML), and vertical (VT) directions were assessed. Main effects of conditions and interactions were evaluated by 2-way repeated measures analysis of variance. Our results showed no interactions between arm swing and slope; however, we found main effects of arm swing and main effects of slope. As expected, uphill and downhill sections of the rolling-hills yielded opposite stepping and postural strategies compared to level walking, and active and held arm swings led to opposite postural strategies compared to normal arm swing. Arm swing effects were consistent across slope conditions. Walking with arms held decreased gait speed, indicating a level of caution, but maintained stability comparable to that of walking with normal arm swing. Active arm swing increased both step width variability and ML-MoS during downhill sections. Alternately, ML-MoS was larger with increased step width and double support time during uphill sections compared to level, which demonstrates that distinct base of support strategies are used to manage arm swing compared to slope. The variability of the rolling-hills also required proactive base of support changes despite the mild slopes to maintain balance.

Limb movement, coordination and muscle activity during a cross-coordination movement on a stable and unstable surface

BACKGROUND

At a clinical level, the intensity of dynamic balance tasks incorporating cross-coordination movements (CCM) is typically progressed by changing the stability of the support surface on which the movement is undertaken. However, biomechanical changes in CCMs performed on stable and unstable surfaces have not yet been quantified.

RESEARCH QUESTION

Do movement patterns, muscle activity, coordination strategies, knee joint loading and center of mass (CoM) movement differ during a CCM performed on stable and unstable surfaces?

METHODS

Motion analysis was used to monitor limb kinematics and surface electromyography to analyze supporting leg muscle activity in sixteen healthy athletes during a single-limb support task involving a cyclic CCM on a stable and unstable surface. Angle-angle plots were used to explore coordination strategies in sagittal movement of the hip and shoulder, while differences in kinematics and muscle activity between stable and unstable conditions were evaluated using dependent t-tests (α-level = 0.05).

RESULTS

CCMs on an unstable surface were performed at a slower speed (p < .05), with a more flexed posture of the support knee (p < .05) and ankle (p < .05) and resulted in reduced hip and shoulder movement of the swing limbs (p < .05). Instability increased activation of selected muscles of the ankle and knee (p < .05), resulted in a two-fold increase in the peak knee adduction moment (p < .05), and was accompanied by greater CoM movement (p < .05). Three coordination patterns of the swing limbs observed when performing CCM on a stable surface, which were mostly preserved on the unstable surface.

SIGNIFICANCE

Despite adopting several stabilization strategies, CCM undertaken on an unstable surface still evoked greater excursion of the center of mass and, as such, presented a greater challenge to sensorimotor control. Adding instability in form of a swinging platform provides progression of dynamic balance CCM difficulty in an athletic population.

Muscle Synergies and Coherence Networks Reflect Different Modes of Coordination During Walking

When walking speed is increased, the frequency ratio between the arm and leg swing switches spontaneously from 2:1 to 1:1. We examined whether these switches are accompanied by changes in functional connectivity between multiple muscles. Subjects walked on a treadmill with their arms swinging along their body while kinematics and surface electromyography (EMG) of 26 bilateral muscles across the body were recorded. Walking speed was varied from very slow to normal. We decomposed EMG envelopes and intermuscular coherence spectra using non-negative matrix factorization (NMF), and the resulting modes were combined into multiplex networks and analyzed for their community structure. We found five relevant muscle synergies that significantly differed in activation patterns between 1:1 and 2:1 arm-leg coordination and the transition period between them. The corresponding multiplex network contained a single module indicating pronounced muscle co-activation patterns across the whole body during a gait cycle. NMF of the coherence spectra distinguished three EMG frequency bands: 4-8, 8-22, and 22-60 Hz. The community structure of the multiplex network revealed four modules, which clustered functional and anatomical linked muscles across modes of coordination. Intermuscular coherence at 4-22 Hz between upper and lower body and within the legs was particularly pronounced for 1:1 arm-leg coordination and was diminished when switching between modes of coordination. These findings suggest that the stability of arm-leg coordination is associated with modulations in long-distant neuromuscular connectivity.

Nordic walking influence on biomechanical parameters: a systematic review

INTRODUCTION

Nordic walking (NW) as a form of physical activity has been shown to have benefits in various domains, but little is known about the effect of NW on more specific biomechanical parameters. The purpose is to determine the impact of NW on the following parameters: walking speed/distance, muscle activation, spatiotemporal parameters, kinematics and ground reaction force.

EVIDENCE ACQUISITION

A literature search was carried out in different databases from October 2008 to October 2018. This review was conducted and reported in accordance with the PRISMA statement. Finally, 42 studies with a median PEDro Score of 5.5/10 were included.

EVIDENCE SYNTHESIS

The included studies reported increased walking distance (+14.8%, P<0.05), walking speed (+25.5%, P<0.05), and stride length (+10.4%, P<0.05), but decreased cadence (-6.2%, P<0.05). NW generally increased: muscle activation and strength for upper limbs; upper and lower limb range of motion, and ground reaction force.

CONCLUSIONS

NW has beneficial effects on many biomechanical parameters. It appears to be an effective way of doing physical activity and could be used in physical rehabilitation or in daily life.

Characterizing gait abnormalities in patients with cervical spondylotic myelopathy: a neuromuscular analysis

BACKGROUND CONTEXT

Gait impairment is a hallmark of cervical spondylotic myelopathy (CSM). It has been shown to affect quality of life but has not been well defined. Further electromyographic (EMG) characterization of the gait cycle may help elucidate the true neuromuscular pathology with implications on prognosis and rehabilitation techniques.

PURPOSE

This study compares neuromuscular activity in patients with CSM to that of healthy age-matched controls.

STUDY DESIGN

Nonrandomized, prospective, concurrent control cohort study.

METHODS

Neuromuscular activity was measured in 40 patients with symptomatic CSM during a series of over-ground gait trials at a self-selected speed before surgical intervention. External oblique, multifidus, erector spinae, rectus femoris, semitendinosus, tibialis anterior, medial gastrocnemius, and medial deltoid were assessed. Identical measurements were taken in 25 healthy control patients. Differences in time of muscle onset, peak EMG, time to peak EMG, and integrated electromyography (iEMG) were assessed using one-way ANOVA.

RESULTS

There were no significant differences between patients with CSM and healthy controls with respect to time of muscle contraction onset. Peak EMG muscle activity was significantly higher in the medial deltoid of patients with CSM (39.3% vs. 23.3% sMVC, p=.042), but no other differences were seen in the remaining muscles tested. They also demonstrated significantly longer time to peak EMG muscle activity compared with controls in 5 of the 8 muscles tested, including the multifidus (20.2 vs. 16.8 ms, p=.050), erector spinae (18.2 vs. 8.9 ms, p<.001), semitendinosis (26.3 vs. 22.4 ms, p=.037), tibialis anterior (14.7 vs. 11.0 ms, p=.050), and medial deltoid (24.2 vs. 9.2 ms, p<.001). Compared with controls, patients with CSM demonstrated significantly higher iEMG activity in the semitendinosis (586.5% vs. 272.5 sMVC, p=.047) and medial deltoid (87.62% vs. 22.5% sMVC, p=.008).

CONCLUSIONS

The onset of muscle activity is not delayed in CSM patients, but many key muscles take longer to fully contract. This produces a situation in which patients with CSM are unable to fully fire their muscles with sufficient speed to maintain a normal gait. The core and lower extremity muscles do not contract with increased peak amplitude in response, but the deltoid and hamstring muscles are more active, suggesting compensatory activity as patients attempt to maintain balance. The end result is less efficient ambulation. These findings provide a more nuanced understanding of gait in individuals suffering from CSM and may have implications on rehabilitation protocols.