A Multiroute Signal Control Model considering Coordination Rate of Green Bandwidth

Oriented to characteristics of the inflow and outflow of routes in urban road network, we modified the classical fundamental green wave bandwidth model, in which separate turning green wave band is available for traffic flow from subarterials merging into an arterial, and this variable green wave band can be more flexible to service the commuting traffic. Moreover, with the analysis of the mapping characteristics of the phase coordination rate, the concept of the coordination rate of green wave bandwidth was proposed, with which as the objective function, a multiroute signal coordination control model was established, and this model is a mixed integer linear programming problem with the overall optimal coordination rate of inbound, outbound, and turning movement as the objective. Finally, a case study was given with road network in Suzhou Industrial Park, Jiangsu Province, China. From the simulation results, we can conclude that the coordinated distribution of the model proposed in this study is more stable; the fluctuation range is 0.09, which is less than that of optimization scheme in classical signal timing software Synchro, which is 0.33; and the total route delay can also be reduced by 15% compared to the current situation and 3.3% compared to Synchro optimization solution.

Does Subthalamic Deep Brain Stimulation Impact Asymmetry and Dyscoordination of Gait in Parkinson’s Disease?

Background. Subthalamic deep brain stimulation (STN-DBS) is an effective treatment for selected Parkinson’s disease (PD) patients. Gait characteristics are often altered after surgery, but quantitative therapeutic effects are poorly described. Objective. The goal of this study was to systematically investigate modifications in asymmetry and dyscoordination of gait 6 months postoperatively in patients with PD and compare the outcomes with preoperative baseline and to asymptomatic controls without PD. Methods. A convenience sample of thirty-two patients with PD (19 with postural instability and gait disorder (PIGD) type and 13 with tremor dominant disease) and 51 asymptomatic controls participated. Parkinson patients were tested prior to the surgery in both OFF and ON medication states, and 6-months postoperatively in the ON stimulation condition. Movement Disorder Society-Unified Parkinson’s Disease Rating Scale (MDS-UPDRS) I to IV and medication were compared to preoperative conditions. Asymmetry ratios, phase coordination index, and walking speed were assessed. Results. MDS-UPDRS I to IV at 6 months improved significantly, and levodopa equivalent daily dosages significantly decreased. STN-DBS increased step time asymmetry (hedges’ g effect sizes [95% confidence interval] between pre- and post-surgery: .27 [-.13, .73]) and phase coordination index (.29 [-.08, .67]). These effects were higher in the PIGD subgroup than the tremor dominant (step time asymmetry: .38 [-.06, .90] vs .09 [-.83, 1.0] and phase coordination index: .39 [-.04, .84] vs .13 [-.76, .96]). Conclusions. This study provides objective evidence of how STN-DBS increases asymmetry and dyscoordination of gait in patients with PD and suggests motor subtypes‐associated differences in the treatment response.

The effect of levodopa on bilateral coordination and gait asymmetry in Parkinson’s disease using inertial sensor

This study aimed to evaluate the effect of levodopa on the phase coordination index (PCI) and gait asymmetry (GA) of patients with Parkinson’s disease (PD) and to investigate correlations between the severity of motor symptoms and gait parameters measured using an inertial sensor. Twenty-six patients with mild-to-moderate-stage PD who were taking levodopa participated in this study. The Unified Parkinson’s Disease Rating Scale part III (UPDRS III) was used to assess the severity of motor impairment. The Postural Instability and Gait Difficulty (PIGD) subscore was calculated from UPDRS III. Patients were assessed while walking a 20-m corridor in both “OFF” and “ON” levodopa medication states, and gait analysis was performed using inertial sensors. We investigated the changes in gait parameters after taking levodopa and the correlations between UPDRS III, PIGD, and gait parameters. There was a significant improvement in PCI after taking levodopa. No significant effect of levodopa on GA was found. In “OFF” state, PCI and GA were not correlated with UPDRS III and PIGD. However, in “ON” state, PCI was the only gait parameter correlating with UPDRS III, and it was also highly correlated with PIGD compared to other gait parameters. Significant improvement in bilateral-phase coordination was identified in patients with PD after taking levodopa, without significant change in gait symmetricity. Considering the high correlation with UDPRS III and PIGD in “ON” states, PCI may be a useful and quantitative parameter to measure the severity of motor symptoms in PD patients who are on medication.

Walking on a Vertically Oscillating Platform with Simulated Gait Asymmetry

Asymmetric gait is associated with pain, injury, and reduced stability in patient populations. Data from side by side walking suggest that unintentional synchronization with an external cue may reduce gait asymmetry. Two types of asymmetric gait were examined here: (1) mass imbalance between limbs to simulate single limb amputation and (2) restriction of plantarflexion during toe-off to simulate reduced propulsion from neurological impairment. Twenty-five healthy participants walked normally and with simulated gait asymmetry on a custom-designed treadmill that oscillated in the vertical direction via pneumatic actuation (amplitude: 2 cm, frequency: participant’s preferred step frequency). Swing Time Asymmetry (STA) and Phase Coordination Index (PCI) both increased significantly with the application of unilateral mass and plantarflexion restriction (p < 0.001). However, walking with simulated asymmetry did not alter unintentional synchronization with the treadmill motion. Further, oscillation of the treadmill did not improve STA or PCI while walking with simulated asymmetry. Analysis of synchronized step clusters using the Weibull survival function revealed that synchronization with the platform persisted for longer durations when compared with data from side by side walking. These results suggest that walking on a vertically oscillating surface may not be an effective approach for improving gait asymmetry.

Does Subthalamic Deep Brain Stimulation Impact Asymmetry and Dyscoordination of Gait in Parkinson’s Disease?

BackgroundSubthalamic deep brain stimulation is an effective treatment for selected Parkinson’s disease patients. Axial deficits including postural stability and gait characteristics are often altered after surgery, but quantitative gait-related therapeutic effects are poorly described.ObjectiveThe goal of this study was to systematically investigate modifications in asymmetry and dyscoordination of gait six-months post-operatively in patients with Parkinson’s disease, and compare the outcomes with preoperative baseline and to asymptomatic controls.MethodsThirty-two patients with Parkinson’s disease (19 with postural instability and gait disorder type, 13 with tremor-dominant disease) and 51 asymptomatic controls participated. Parkinson patients were tested prior to the surgery in both OFF and ON medication states, and six months post-operatively in the ON stimulation condition. Clinical outcome parameters and medication were compared to preoperative conditions. Asymmetry ratios, phase coordination index, and walking speed were assessed.ResultsPatients’ clinical outcomes as assessed by standard clinical parameters at six-months improved significantly, and levodopa-equivalent daily dosages were significantly decreased. STN-DBS increased step time asymmetry (hedges’ g effect sizes [confidence intervals] between pre- and post-surgery: 0.27 [-0.13,0.73]) and phase coordination index (0.29 [-0.08,0.67]). These effects were higher in the Postural Instability and Gait Disorder subgroup than the Tremor Dominant (step time asymmetry: 0.38 [-0.06,0.90] vs. 0.09 [-0.83,1.0] and phase coordination index: 0.39 [-0.04,0.84] vs. 0.13 [-0.76,0.96]).ConclusionThis study provides objective evidence of how subthalamic deep brain stimulation increases asymmetry and dyscoordination of gait in patients with Parkinson’s disease, and suggests motor subtypes-associated differences in the treatment response.

Antiphase crew rowing on water: a first case study.

In crew rowing, agents need to mutually coordinate their movements to achieve optimal performance (De Poel, De Brouwer, &amp; Cuijpers, 2016). Traditionally, rowers aim to achieve perfect synchronous (in-phase) coordination. Somewhat counterintuitively, however, crew rowing in an antiphase pattern (i.e., alternating strokes) would actually be mechanically more efficient: it diminishes the within-cycle surge velocity fluctuations of the boat, thereby reducing hydrodynamic drag and hence power losses with 5-6% (Brearly &amp; DeMestre, 1998; De Poel et al., 2016; De Brouwer, De Poel, &amp; Hofmijster, 2013; Cuijpers, Zaal, &amp; De Poel, 2015, Greidanus, Delfos, &amp; Westerweel, 2016). However, from coordination dynamics an antiphase pattern is expected to be less stable, especially at high stroke rates such as in racing, which may even lead to transitions to the more stable in-phase pattern (Haken, Kelso, &amp; Bunz, 1985). Recent laboratory studies in which rower dyads performed antiphase crew coordination on two mechanically coupled ergometers have provided promising results (De Brouwer et al., 2013; De Poel et al., 2016; Cuijpers et al., 2015;). However, counter to ergometer rowing, rowing on-water also requires handling of the oars and boat movements in three dimensions, such as lateral balance and forward speed. Furthermore, the boat has actual forward speed. Therefore, the next step in this endeavour is to examine antiphase crew rowing and associated boat movements on water. Here we report results of the first test case.

Kinematic Variables of Disabled Swimmers and Their Correlation With the International Paralympic Committee Classification

This study described the kinematic variables of disabled swimmers’ performance and correlated them with their functional classification. Twenty-one impaired swimmers (S5–S10) performed 50-m maximum front-crawl swimming while being recorded by four underwater cameras. Swimming velocity, stroke rate, stroke length, intracycle velocity variation, stroke dimensions, hand velocity, and coordination index were analyzed. Kendall rank was used to correlate stroke parameters and functional classification with p < .05. Swimming velocity, stroke length, and submerged phase were positively correlated with the para swimmers functional classification (.61, .50, and .41; p < .05, respectively), while stroke rate, velocity hand for each phase, coordination index, and intracyclic velocity variation were not (τ between −.11 and .45; p > .05). Thus, some objective kinematic variables of the impaired swimmers help to support current classification. Improving hand velocity seems to be a crucial point to be improved among disabled swimmers.

A Re-Appraisal of the Effect of Amplitude on the Stability of Interlimb Coordination Based on Tightened Normalization Procedures

The stability of rhythmic interlimb coordination is governed by the coupling between limb movements. While it is amply documented how coordinative performance depends on movement frequency, theoretical considerations and recent empirical findings suggest that interlimb coupling (and hence coordinative stability) is actually mediated more by movement amplitude. Here, we present the results of a reanalysis of the data of Post, Peper, and Beek (2000), which were collected in an experiment aimed at teasing apart the effects of frequency and amplitude on coordinative stability of both steady-state and perturbed in-phase and antiphase interlimb coordination. The dataset in question was selected because we found indications that the according results were prone to artifacts, which may have obscured the potential effects of amplitude on the post-perturbation stability of interlimb coordination. We therefore redid the same analysis based on movement signals that were normalized each half-cycle for variations in oscillation center and movement frequency. With this refined analysis we found that (1) stability of both steady-state and perturbed coordination indeed seemed to depend more on amplitude than on movement frequency per se, and that (2) whereas steady-state antiphase coordination became less stable with increasing frequency for prescribed amplitudes, in-phase coordination became more stable at higher frequencies. Such effects may have been obscured in previous studies due to (1) unnoticed changes in performed amplitudes, and/or (2) artifacts related to inappropriate data normalization. The results of the present reanalysis therefore give cause for reconsidering the relation between the frequency, amplitude, and stability of interlimb coordination.