Laser-Guided Visual Cueing Modulates Spatiotemporal Gait Dynamics During Transitions in Parkinson’s

The combination of transcranial direct current stimulation (tDCS) with balance training could integrate central and peripheral neural mechanisms. This study aimed to investigate the effects of concurrent balance training and tDCS over the supplementary motor area (SMA) on anticipatory postural adjustments during gait initiation (GI) in persons with chronic ankle instability (CAI). Balance training will increase the center of pressure (COP) velocity and displacement during GI phases in all participants, and those receiving real tDCS will show greater increases. Randomized controlled trial. Level 2. A total of 32 subjects were allocated to 2 groups: (1) intervention (balance training plus real tDCS) and (2) control (balance training plus sham tDCS). Outcome measures were COP-related parameters (displacement and velocity) during phases of GI (anticipatory, weight transition, and locomotor). The results showed that, in the anticipatory phase, the anteroposterior displacement of the COP was increased significantly at posttest relative to pretest across both groups, F(1,30) = 5.733, P = 0.02. In addition, both groups revealed an increase in the mediolateral COP velocity at posttest, F(1,30) = 10.523, P < 0.01. In the weight transition phase, both groups had higher mediolateral COP velocity at posttest, F(1,30) = 30.636, P < 0.01. In the locomotor phase, in both groups, the anteroposterior COP velocity was increased significantly at posttest compared with pretest, F(1,30) = 5.883, P = 0.02. Both groups demonstrated improvements in the anticipatory and execution phases of GI. Since no between-group difference was found, it can be interpreted that the anodal tDCS applied over the SMA has no added value over sham stimulation. Balance training is beneficial for persons with CAI and can improve the anticipation and execution phases of GI without the aid of brain stimulation.

Repeatability and variability of baropodometric and spatio-temporal gait parameters – Results in healthy subjects and in stroke patients

Gait termination requires an interaction between the biomechanical and neuromuscular systems to arrest forward momentum. Currently, the biomechanical characteristics of gait termination have been demonstrated; however, the neural mechanism of gait termination remains unclear. This study aimed to investigate cortical activity during gait termination using functional near-infrared spectroscopy (fNIRS). Thirteen healthy younger adults (mean age:24.0 ± 1.7) participated in this study. All participants performed three experimental sessions: planned gait termination (PGT), unplanned gait termination (UGT), and walking. Each experimental session comprised a block paradigm design (three cycles; 20 s resting, 45 s task). Cortical activity in the dorsolateral prefrontal cortex (DLPFC), supplementary motor area (SMA), and primary motor cortex (M1) and spatiotemporal parameters were measured. We compared the cortical activities and spatiotemporal parameters among PGT, UGT, and walking sessions. In addition, we performed Pearson correlations between hemodynamic responses and spatiotemporal parameters. The PGT was activated in the right DLPFC, whereas the UGT and walking were activated in the left SMA (p < 0.05). Comparing cortical activation between sessions, both the PGT and UGT showed significantly higher activation in the right DLPFC than during walking (p < 0.05). There were no significant differences in cortical activity between PGT and UGT (p > 0.05). In addition, the gait termination time revealed moderate positive correlation with hemodynamic responses in the right DLPFC (p < 0.05). Our results indicate that the right DLPFC is associated with gait termination, regardless of gait termination type. Our findings provide the potential implication that the hemodynamic response in the right DLPFC would be a biomarker to evaluate the ability of gait termination.

Hemiplegic individuals often exhibit gait impairments. Current technologies allow for simple and fast acquisition of spatiotemporal gait parameters and gait Symmetry Indices (SI). Gait SI have been associated with instability and fall risk. These data may therefore prove an important addition to the already common conventional clinical measures, e.g. the 10 Meter Walk Test (10MWT), Berg Balance Scale (BBS), Timed Up and Go Test (TUG), Six Minute Walk Test (6MWT) and the Motor Functional Independence Measure (MFIM). However, the prediction of these conventional clinical measures using spatiotemporal gait parameters and gait SI for individuals post stroke, has yet to be thoroughly investigated. We aimed to evaluate the correlation between spatiotemporal gait parameters and commonly-used clinical gait test scores, and to predict common clinical measures by spatiotemporal gait parameters in patients post stroke. In this cross-sectional retrospective study, spatiotemporal data were collected from files of adult patients (n = 70) post stroke, who performed one or more of the aforementioned functional evaluations within 1 year following stoke. Correlations were also performed for 53 of these subjects who performed all the tests in the subacute stage. High correlations (>0.7) were found between 10MWT, 6MWT and TUG and between diverse spatiotemporal parameters. Spatiotemporal parameters significantly predicted the 6MWT (R2 = .743), TUG (R2 = .668), 10MWT (R2 = .552), MFIM (R2 = .513), and the BBS (R2 = .556). An objective computerized evaluation producing spatiotemporal and symmetry gait parameters is compatible with common functional gait measures and might prove more advantageous in patient evaluation, since it provides additional multiple data, easily and quickly acquired.

Trajectory of the body COG and COP during initiation and termination of gait

Gait initiation is a fundamental human task, requiring one or more anticipatory postural adjustments (APA) prior to stepping. Deviations in amplitude and timing of APAs exist in Parkinson's disease (PD), causing dysfunctional postural control which increases the risk of falls. The motor cortex and basal ganglia have been implicated in the regulation of postural control, however, their dynamics during gait initiation, relationship to APA metrics, and response to pharmacotherapy such as levodopa are unknown. To address these questions, we streamed electrocorticography (ECoG) potentials from the premotor and primary motor cortices, as well as local field potentials (LFPs) from the globus pallidus in five people with PD exhibiting gait and balance dysfunction during a cued gait initiation task. Amplitude and timing of APA were evaluated with force plates and synchronized to the neural data. Subjects performed gait initiation trials under ON and LOW levodopa conditions to assess effects of medication on APA metrics and underlying neural dynamics. All subjects demonstrated pallidal and cortical oscillatory changes during different phases of gait initiation. Grouped analysis revealed that from quiet standing to the first foot step, pallidal beta power showed stepwise decrease and broadband gamma power increases, whereas cortical potentials showed low frequency (theta, alpha, beta) power decrease during gait initiation, regardless of medication state. The pallidum and motor cortices also became increasingly coherent during gait initiation compared to quiet standing prior to APA onset. Using linear mixed models, we found that while pallidal gamma powers are predictive of APA scaling, pallidal-cortical coherence (theta, alpha, beta) and premotor-M1 gamma coherence are predictive of APA timing. Our study is the first detailed characterization of basal-ganglia cortical circuit dynamics during human gait initiation. We identified significant pallidal motor cortical power and coherence changes that underlie the amplitude and timing of APA which appear to be independent of medication states of the study subjects. Our results provide evidence for a model where synchronized premotor and motor cortical activities transiently couple with the globus pallidus to regulate the timing of postural responses, and local pallidal activity regulate the amplitude of postural changes during gait initiation. It suggests that abnormal pallidal outflow and synchronization between the pallidum and motor cortices may be a pathophysiological mechanism underlying disordered postural response in Parkinson's disease.

The aim of the current study was to determine the extent to which pleasant and unpleasant emotional states impact the initiation of forward gait. Participants initiated gait and walked for several steps following the presentation of low arousing pleasant, high arousing pleasant, low arousing unpleasant, high arousing unpleasant, and neutral pictures. Reaction time, displacement, and velocity of the center of pressure (COP) trajectory, and length and velocity of the first and second steps were calculated. Exposure to the highly arousing unpleasant pictures reduced reaction times compared to all other affective conditions. Compared to the low arousing unpleasant pictures, exposure to the high and low arousing pleasant pictures increased the displacement of the COP movement during the anticipatory postural adjustment phase of gait initiation. Additionally, exposure to the low arousing pleasant pictures increased the velocity of the COP movement during the anticipatory postural adjustment phase, compared to the high and low arousing unpleasant pictures. Exposure to the high and low arousing pleasant pictures increased the velocity of the first step relative to the low arousing unpleasant pictures. These findings demonstrate that highly arousing unpleasant emotional states accelerate the initial motor response, but pleasant emotional states generally facilitate the initiation of forward gait due to the approach-oriented directional salience of the movement. These findings extend the scope of the motivational direction hypothesis by demonstrating the effects of emotional reactivity on the initiation of gait.

Impaired postural control is a cardinal symptom of concussion. Impairments during dynamic tasks, such as gait termination (GT), may persist beyond recovery and manifest in altered movement strategies. PURPOSE: To evaluate the effects of sport-related concussion on center of pressure (CoP) displacements during planned GT. METHODS: Nineteen concussed NCAA Division I student-athletes (age: 19±0.8 years, height: 177.0±10.1 cm, weight: 83.3±20.0 kg) and nineteen matched healthy controls (age: 20.4±1.22 years, height: 173.8±8.9 cm, weight: 80.2±17.6 kg) performed five planned GT trials using a Gaitrite portable walkway system and four 400mmx600mm force plates (1,000Hz). Gait trials were conducted during pre-season baseline testing (Pre) and on Day 1 post-concussion (Post) for the injured subjects, and on two matched days for the control group. Center of pressure displacements were calculated on the force plates in both the mediolateral (ML) and anteroposterior (AP) directions during the three phases of CoP (S1, S2, S3), which correspond to the locomotor, single leg stance and postural adjustment phases of GT. All data were compared using a 2x2 (group x time) repeated measures ANOVA. RESULTS: There were significant interactions for S1ML (Control Pre: 16.8±5.4 cm, Post: 16.4±5.9 cm; Concussed Pre: 17.9±6.1 cm, Post: 13.2±6.6 cm, p=0.042) and S2AP (Control Pre: 3.9±4.8 cm, Post: 4.0±4.2 cm; Concussed Pre: 9.5±5.6 cm, Post: 18.6±16.7 cm, p=0.030). Main effects were present for S1AP (Control Pre: 64.0±5.6 cm, Post: 61.2±6.4 cm; Concussed Pre: 60.2±9.5 cm, Post: 50.6±19.7 cm, p=0.020), S1ML (p=0.015) and S2AP (p=0.027). There were no significant main effects or interactions in S3. CONCLUSION: Following concussion, marked alterations are present in the first two phases of CoP during planned GT. The decreased S1 and increased S2, which are typically associated with a worsened postural control, allude to a conservative motor control approach to GT. This conservative strategy appears to be an attempt to keep the center of mass closer to the base of support, along with a wider bipedal stance during GT. Supported by: NINDS 1R15NS070744-01A1.

BackgroundGait initiation (GI) can be divided into three sections according to the center of pressure (COP) trace (S1, S2, and S3). Almost all studies do not separate each phase of the GI profile in postural control assessment and muscular investigation, whereas differences in the COP and muscles are found in each phase of the GI profile in people with gait problems.MethodsTwenty individuals with CAI and twenty healthy controls were included in the present study. A force plate synchronized with Qualisys motion analysis, MEGAWIN electromyography, and a pair of auditory cues were used for data capture. The participants carried out five trials of GI with the affected leg (dominant leg). The peak and mean COP excursions; the mean and maximum velocities of COP excursion during S1, S2,, S3, and the total phases in the mediolateral (ML) and anterior‒posterior (AP) directions; the root mean square (RMS); and the onset activity of the Tibialis Anterior (TA) and Soleus (SOL) muscles for both legs were used for statistical analysis. Independent t tests and Mann‒Whitney U tests were used for statistical analysis on the basis of a significance level of ≤ 0.05.ResultsCompared with those of healthy controls, independent t tests revealed a significant decrease in the peak COP excursion in the AP direction during S2 (P = 0.021) and in the mean velocity of COP excursion in the AP direction during S1 (P = 0.044) in the CAI group. Additionally, there was a significant increase in the duration of S1 in the GI profile (P = 0.045) in the CAI group compared with the healthy control group. There was no significant difference in the other COP variables, TA or SOL RMS or onset activity for either leg during S1, S2, or S3 between the two groups (P > 0.065).ConclusionIndividuals with CAI exhibit increased stiffness in the AP direction in the injured ankle. This leads to a reduction in the velocity and peak of COP excursion, as well as an increase in the time required for postural control adjustment. These findings highlight the challenges individuals with CAI may face in meeting postural demands when trying to unload the affected foot.Ethical codeIR.SBMU.RETECH.REC.1402.095, 2023–5-28.

This study aims to compare 2 methods of assessing the postural phase of gait initiation, in regard to intrasession reliability, in healthy and poststroke subjects. As a secondary aim, this study aims to analyze anticipatory postural adjustments during gait initiation based on the center of pressure (CoP) displacements in poststroke participants. The CoP signal was acquired during gait initiation in 15 poststroke subjects and 23 healthy controls. Postural phase was identified through a baseline-based method and a maximal displacement-based method. In both healthy and poststroke participants, higher intraclass correlation coefficient and lower coefficient of variation values were obtained with the baseline-based method when compared with the maximal displacement-based method. Poststroke participants presented decreased CoP displacement backward and toward the first swing limb compared with controls when the baseline-based method was used. With the maximal displacement based method, there were differences between groups only regarding backward CoP displacement. Postural phase duration in medial-lateral direction was also increased in poststroke participants when using the maximal displacement based method. The findings obtained indicate that the baseline-based method is more reliable detecting the onset of gait initiation in both groups, while the maximal displacement-based method presents greater sensitivity for poststroke participants.

Imaginary tasks can be used to investigate the neurophysiology of gait. In this study, we explored the cortical control of gait-related imagery in 21 healthy volunteers using functional magnetic resonance imaging. Imaginary tasks included gait initiation, stepping over an obstacle, and gait termination. Subjects watched a video clip that showed an actor in gait motion under an event-related design. We detected activation in the supplementary motor area during major gait-related imagery tasks, and especially during gait initiation. During gait termination and stepping over an obstacle, the amount of cortical resources allocated to the imaginary tasks included a large visuomotor network comprising the dorsal and ventral premotor areas. We conclude that our paradigm to study the cortical control of gait may help in elucidating the pathophysiology of higher-level gait disorders.

Prospective cohort study. The aim of this study was to 1) determine postural stability and spatiotemporal gait parameters and 2) characterize dynamic stability and variances in angular momentum (AM) of preoperative cervical spondylotic myelopathy (CSM) patients compared with healthy controls. CSM is the most common cause of spinal cord dysfunction in the world and can lead to significant functional deficits including proprioception and gait disturbances. Biomechanical feedback mechanisms compensating for these deficits, specifically AM regulation, have remained largely unexplored. Fifty-six subjects: 32 preoperative Nurick grade 2 or 3 CSM patients and 24 controls were included. Standing balance trials were performed on a single force plate, while walking trials were conducted at self-selected pace over a 15 m runway and a series of five force plates. All trials were recorded with three-dimensional motion analysis cameras and gait modeling software was utilized to calculate stability, spatiotemporal gait parameters, and joint kinematics. Tilted ellipse area, a measure of center of pressure variance and postural stability, was significantly greater among CSM patients (847.54 ± 764.33 mm2vs. 258.18 ± 103.35 mm2, P < 0.001). These patients had two times as much variance medial-lateral (72.12 ± 51.83 mm vs. 29.15 ± 14.95 mm, P = 0.001) and over three times as much anterior-posterior (42.25 ± 55.01 mm vs. 9.17 ± 4.83 mm, P = 0.001) compared with controls. Spatiotemporal parameters indicated that the CSM patients tending to have slower, shorter, and wider gait compared with controls, while spending greater amount of time in double support. Compensatory AM among CSM patients was significantly increased in all three anatomic planes, where whole-body AM was approximately double that of controls (0.057 ± 0.034 vs. 0.023 ± 0.006), P < 0.001). Preoperative CSM patients showed significant alterations in spatiotemporal gait parameters and postural stability compared with controls, consistent with prior literature. Likewise, angular momentum analysis demonstrates that these patients have globally increased body excursion to maintain dynamic balance.Level of Evidence: 3.

Children require less gait kinematic adaptations to pull a trolley than to carry a backpack

The aim of this study was to examine differences in gait kinematics and spatiotemporal parameters in ambulatory children and adolescents with bilateral spastic cerebral palsy (BSCP) among Gross Motor Function Classification System (GMFCS) levels I-III. A retrospective review was conducted of individuals with BSCP who had three-dimensional motion analysis (3DGA) at one of seven pediatric hospitals. Means and standard deviations of each gait parameter were stratified by GMFCS levels (I-III) and for a typically developing comparison group. Data from 292 children and adolescents with BSCP (189 males, 103 females; mean age 13 y) were compared to a typically developing comparison group (24 male, 26 female; mean age 10 y 6 mo). Gait patterns differed from typically developing in all GMFCS levels, with increasing deviation as GMFCS level increased in 21 out of 28 parameters. Despite significant differences in selected mean kinematic parameters among GMFCS levels such as knee angle at initial contact of 24°, 29°, and 41° in GMFCS levels I, II and III respectively, there was also substantial overlap among GMFCS levels. GMFCS levels cannot be identified using specific gait kinematics. Treatment decisions should be guided by comprehensive 3DGA that allows measurement of gait impairments at the joint level for each individual.

Walking speed is a measure of functional mobility that is relatively easy to quantify. In people with lower limb amputation, reduced walking speed has been linked with specific atypical spatiotemporal gait parameters. However, the influence of atypical spatiotemporal gait parameters on the walking speed of people with unilateral transtibial amputation (TTA) and transfemoral amputation (TFA) remains unclear. To identify spatiotemporal gait parameters influencing walking speed of people with unilateral TTA or TFA. Cross-sectional. The 10-meter walk test (10mWT) was used to measure walking speed, and an instrumented walkway was used to record spatiotemporal gait parameters. Regression analyses were used to determine the best subset of spatiotemporal gait parameters that influence the walking speed of people with TTA and TFA. The study included 43 people with TTA and 49 with TFA. In the TTA group, spatiotemporal gait parameters accounted for 65.5% of the variance in walking speed, with prosthetic single limb support accounting for 52.2%, prosthetic terminal double limb support accounting for 8.9%, and stride width accounting for 4.4%. In the TFA group, intact swing accounted for 46.7% of the variance in walking speed. There was no significant difference in walking speed between the TTA and the TFA groups ( p > 0.05). The study's results highlight specific spatiotemporal gait parameters that affect the walking speed of people with unilateral TTA and TFA. In addition, results suggest that walking speed over short distances is not confounded by amputation level (i.e., TTA and TFA).