Gait initiation by patients with lower-half parkinsonism

Arm Swing while Walking and Running: A New Clinical Feature to Separate Parkinson's Disease from Functional Parkinsonism

BACKGROUND

Functional parkinsonism is an important differential diagnosis of Parkinson's disease (PD). Based on anecdotal experience, we hypothesized that arm swing while walking and running could differentiate these two conditions, but this assumption has not been previously explored systematically.

OBJECTIVES

To examine differences in arm swing while walking and running between patients with PD and functional parkinsonism.

METHODS

We analyzed blinded video assessments of arm swing and other gait parameters in patients with asymmetrical PD (n = 81) and functional parkinsonism (n = 8) while walking and running. The groups were matched for age, sex and disease duration.

RESULTS

In contrast to those with PD, patients with functional parkinsonism (i) were more likely to have a marked asymmetry in arm swing while walking (5/8 vs. 25/81; P = 0.06), (ii) were less likely to improve arm swing while running with full effort (3/8 vs. 72/81; P < 0.001) and (iii) demonstrated normal passive arm swing even when asymmetry of arm swing was marked during running/walking (6/6 vs. 9/33; P = 0.002).

CONCLUSIONS

Assessment of arm swing while walking and running and passive arm swing could be important differentiating clinical features between functional parkinsonism and PD.

Effect of Chronic Ankle Instability on the Biomechanical Organization of Gait Initiation: A Systematic Review

This systematic review was conducted to provide an overview of the effects of chronic ankle instability (CAI) on the biomechanical organization of gait initiation. Gait initiation is a classical model used in the literature to investigate postural control in healthy and pathological individuals. PubMed, ScienceDirect, Scopus, Web of Science, and Google Scholar were searched for relevant articles. Eligible studies were screened and data extracted by two independent reviewers. An evaluation of the quality of the studies was performed using the Downs and Black checklist. A total of 878 articles were found in the initial search, but only six studies met the inclusion criteria. The findings from the literature suggest that CAI affects the characteristics of gait initiation. Specifically, individuals with CAI exhibit notable differences in reaction time, the spatiotemporal parameters of anticipatory postural adjustments (APAs) and step execution, ankle-foot kinematics, and muscle activation compared to healthy controls. In particular, the observed differences in APA patterns associated with gait initiation suggest the presence of supraspinal motor control alterations in individuals with CAI. These findings may provide valuable information for the rehabilitation of these patients. However, the limited evidence available calls for caution in interpreting the results and underscores the need for further research.

Can People with Parkinson's Disease Self-Trigger Gait Initiation? A Comparison of Cueing Strategies

BACKGROUND

An external cue can markedly improve gait initiation in people with Parkinson's disease (PD) and is often used to overcome freezing of gait (FOG). It is unknown if the effects of external cueing are comparable if the imperative stimulus is triggered by the person receiving the cue (self-triggered) or an external source.

OBJECTIVE

Two experiments were conducted to compare the effects of self- versus externally triggered cueing on anticipatory postural adjustments (APAs) during gait initiation in people with PD.

METHODS

In experiment 1, 10 individuals with PD and FOG initiated gait without a cue or in response to a stimulus triggered by the experimenter or by the participant. Experiment 2 compared self- versus externally triggered cueing across three groups: healthy young adults (n = 16), healthy older adults (n = 11), and a group with PD (n = 10).

RESULTS

Experiment 1: Externally triggered cues significantly increased APA magnitudes compared to uncued stepping, but not when the same cue was self-triggered. Experiment 2: APAs were not significantly improved with a self-triggered cue compared to un-cued stepping in both the PD and healthy older adult groups, but the young adults showed a significant facilitation of APA magnitude.

CONCLUSION

The effectiveness of an external cue on gait initiation in people with PD and older adults is critically dependent upon whether the source of the trigger is endogenous (self-produced) or exogenous (externally-generated). These results may explain why cueing interventions that rely upon self-triggering of the stimulus are often ineffective in people with PD.

12-Week Exercise Training of Knee Joint and Squat Movement Improves Gait Ability in Older Women

This study analyzed the effects of an exercise training program consisting of a knee joint complex exercise device (leg-link system) with digitally controlled active motion function and squat movement on physical fitness and gait ability of elderly women aged 70 or above. Fifty four (54) elderly women aged 70 or above were divided into three groups as control group (n = 18), aerobic training group (n = 18), and combined training group with resistance and aerobic exercise (n = 18). Health-related physical fitness, gait ability-related physical fitness, and the temporal and spatial parameters of gait ability were compared. The health-related physical fitness after the 12-week training was not significantly altered in control group, whereas combined training group showed significant increase in all factors (p < 0.05) and aerobic training group showed significant increase (p < 0.05) only in the physical efficiency index. The gait ability-related physical fitness and all items of the temporal and spatial parameters of gait were found to have significantly increased (p < 0.05) in combined training group after the 12-week exercise training; however, in aerobic training group, only the factors related to muscular endurance and balance showed significant increase (p < 0.05). This study suggested that the exercise training consisting of knee joint complex exercise with digitally controlled active motion function and squat exercise for strengthening lower extremities and core muscles had positive effects on enhancing the ambulatory competence in elderly women.

Fear of Falling Alters Anticipatory Postural Control during Cued Gait Initiation

Fear of falling can have a profound influence on anticipatory postural control during dynamic balance tasks (e.g., rise-to-toes and leg-raise tasks), with fearful individuals typically exhibiting postural adjustments of smaller magnitudes prior to movement onset. However, very little is known about how fear of falling influences the generation of anticipatory postural adjustments (APAs) during gait initiation; a task in which producing smaller APAs may compromise stability. Sixteen young adults initiated gait as fast as possible following an auditory cue during two conditions: Baseline (ground level), and Threat (fear of falling induced via a platform raised 1.1 m). While the magnitude and duration of APAs did not change between conditions, participants executed steps of shorter lengths during Threat. As APAs during gait initiation are typically proportionate to the length of the first step, the APAs during Threat are therefore disproportionately large (given the shorter step length). We suggest that such failure to scale the APA to the magnitude of the motor output represents a fear-related 'overcompensation', whereby fearful participants sought to ensure that the APA was sufficient for ensuring that their centre of mass was positioned above the support leg prior to gait initiation. During conditions of threat, participants also exhibited greater postural sway prior to initiating gait (i.e., following the auditory cue) and took longer to generate the APA (i.e., impaired reaction). As greater reaction times during voluntary stepping is consistently associated with increased fall-risk, we suggest this as one mechanism through which fear of falling may reduce balance safety.

A Neuromechanical Model of Reduced Dorsiflexor Torque During the Anticipatory Postural Adjustments of Gait Initiation

Anticipatory postural adjustments (APAs) precede gait initiation and function to accelerate the center of mass forward and towards the initial stance leg. Impairments in APA generation, such as those seen in people with Parkinson's disease (PD), can impact the quality of the first step. An initial burst of activity in the dorsiflexor muscle (tibialis anterior) of the stepping leg is an important contributor to the posterior excursion of the center of pressure that accelerates the center of mass forward during an APA. Tibialis anterior activation can be diminished or absent in people with PD; however, the neuromechanical consequence of this diminished dorsiflexor torque on APA generation is not fully understood. Computational models of gait initiation that include components of the neuromuscular system may provide additional insight. In this paper, an inverted pendulum model of the body generated from healthy young adult data was used to simulate reduced dorsiflexor torque during an APA for gait initiation. Forward body lean angle and center of pressure were assessed over various settings of decreased dorsiflexor torque and compared to experimental data from a person with PD. Results from the model demonstrate that reducing the peak dorsiflexor torque by as little as 8-Nm may alter forward body lean and the center of pressure excursion from their nominal trajectories. These results can help inform how much torque is needed from an external device to effectively modulate APAs for gait initiation, as well as provide insight into compensation strategies for reduced dorsiflexor torque in pathology.

Freezing of Gait Boot Camp: feasibility, safety and preliminary efficacy of a community-based group intervention

AIM

In this pilot study, we evaluated the feasibility, safety and preliminary efficacy of a 6-week, community-based group intervention designed to reduce freezing of gait (FOG) for people with Parkinson's disease (PD).

METHODS

Seven people with PD completed 'FOG Boot Camp' provided by the St. Louis Chapter of the American Parkinson Disease Association. We recorded attendance, participant's acceptance of the intervention and adverse events during classes. Pre and post-tests included measures of freezing, balance, motor severity, quality-of-life and gait speed.

RESULTS

No falls or injuries occurred and attendance was high. Participants had favorable feedback and showed reduced freezing and improvements in balance and gait.

CONCLUSION

Preliminary data suggest the FOG boot camp was feasible, safe and effective.

The effects of anodal tDCS over the supplementary motor area on gait initiation in Parkinson's disease with freezing of gait: a pilot study

OBJECTIVE

We investigated if anodal transcranial direct current stimulation (A-tDCS), applied over the supplementary motor areas (SMAs), could improve gait initiation in Parkinson's disease (PD) with freezing of gait (FOG).

METHODS

In this double-blinded cross-over pilot study, ten PD with FOG underwent two stimulation sessions: A-tDCS (1 mA, 10 min) and sham stimulation. Eight blocks of gait initiation were collected per session: (1) pre-tDCS, with acoustic cueing; (2) pre-tDCS, self-initiated (no cue); and (3-8) post-tDCS, self-initiated. Gait initiation kinetics were analyzed with two-way repeated measures ANOVAs for the effects of A-tDCS.

RESULTS

A-tDCS did not significantly improve the magnitude or timing of anticipatory postural adjustments or the execution of the first step during self-initiated gait compared with baseline measures (p > .13). The lack of significant change was not due to an inability to generate functional APAs since external cueing markedly improved gait initiation (p < .01).

CONCLUSIONS

A single dose of A-tDCS over the SMAs did not improve self-initiated gait in PD and FOG. Alternative approaches using a different dose or cortical target are worthy of exploration since individuals demonstrated the capacity to improve.

SIGNIFICANCE

Neuromodulation strategies tailored to facilitate SMA activity may be ineffective for the treatment of gait initiation impairment in people with PD and FOG.

Investigation of Anticipatory Postural Adjustments during One-Leg Stance Using Inertial Sensors: Evidence from Subjects with Parkinsonism

The One-Leg Stance (OLS) test is a widely adopted tool for the clinical assessment of balance in the elderly and in subjects with neurological disorders. It was previously showed that the ability to control anticipatory postural adjustments (APAs) prior to lifting one leg is significantly impaired by idiopathic Parkinson’s disease (iPD). However, it is not known how APAs are affected by other types of parkinsonism, such as frontal gait disorders (FGD). In this study, an instrumented OLS test based on wearable inertial sensors is proposed to investigate both the initial anticipatory phase and the subsequent unipedal balance. The sensitivity and the validity of the test have been evaluated. Twenty-five subjects with iPD presenting freezing of gait (FOG), 33 with iPD without FOG, 13 with FGD, and 32 healthy elderly controls were recruited. All subjects wore three inertial sensors positioned on the posterior trunk (L4–L5), and on the left and right frontal face of the tibias. Participants were asked to lift a foot and stand on a single leg as long as possible with eyes open, as proposed by the mini-BESTest. Temporal parameters and trunk acceleration were extracted from sensors and compared among groups. The results showed that, regarding the anticipatory phase, the peak of mediolateral trunk acceleration was significantly reduced compared to healthy controls (p < 0.05) in subjects with iPD with and without FOG, but not in FGD group (p = 0.151). Regarding the balance phase duration, a significant shortening was found in the three parkinsonian groups compared to controls (p < 0.001). Moreover, balance was significantly longer (p < 0.001) in iPD subjects without FOG compared to subjects with FGD and iPD subjects presenting FOG. Strong correlations between balance duration extracted by sensors and clinical mini-BESTest scores were found (ρ > 0.74), demonstrating the method’s validity. Our findings support the validity of the proposed method for assessing the OLS test and its sensitivity in distinguishing among the tested groups. The instrumented test discriminated between healthy controls and people with parkinsonism and among the three groups with parkinsonism. The objective characterization of the initial anticipatory phase represents an interesting improvement compared to most clinical OLS tests.

Decreased Anticipatory Postural Adjustments During Gait Initiation Acutely Postconcussion

OBJECTIVE

To investigate anticipatory postural adjustments (APAs) during the transitional movement task of gait initiation (GI) in individuals acutely after a concussion.

DESIGN

Cohort study.

SETTING

University research center.

PARTICIPANTS

A population-based sample of participants (N=84) divided into 2 equal groups of acutely postconcussion and healthy student athletes.

INTERVENTION

Participants were tested on 2 occasions: a preinjury baseline test and then the concussion group was retested acutely postconcussion and the healthy student athlete group again at a similar time. All participants completed 5 trials of GI on 4 forceplates.

MAIN OUTCOME MEASURES

The dependent variables were the displacement and velocity of the center of pressure (COP) during the APA phase and initial step kinematics. Comparisons were made with a 2 (group) × 2 (time) repeated-measures analysis of variance.

RESULTS

There was a significant interaction for COP posterior displacement (P<.001) and lateral displacement (P<.001). Posteriorly, post hoc testing identified a significant reduction in the concussion group (pretest: 5.7±1.6cm; posttest: 2.6±2.1cm; P<.001), but no difference in the healthy student athlete group (pretest: 4.0±1.6cm; posttest: 4.0±2.5cm; P=.921). Laterally, post hoc testing identified a significant reduction in the concussion group (pretest: 5.8±2.1cm; posttest: 3.8±1.8cm; P<.001), but no difference in the healthy student athlete group (pretest: 5.0±2.5cm; posttest: 5.2±2.4cm; P=.485).

CONCLUSIONS

The results of this study suggest difficulty in the planning and execution of GI acutely postconcussion, and posterior APA displacement and velocity are highly effective measures of impaired postural control. Finally, the APA phase is linked to the supplementary motor area, which suggests a supraspinal contribution to postconcussion impaired postural control.

Gait initiation and termination strategies in patients with Prader-Willi syndrome

BACKGROUND

Gait Initiation (GI) is a functional task representing one of the first voluntary destabilizing behaviours observed in the development of a locomotor pattern as the whole body centre of mass transitions from a large to a small base of support. Conversely, Gait Termination (GT) consists in the transition from walking to standing which, in everyday life, is a very common movement. Compared to normal walking, it requires higher control of postural stability. For a safe GT, the forward movement of the body has to be slowed down to achieve a stable upright position. Stability requirements have to be fulfilled for safe GT. In individuals with Prader-Willi syndrome (PWS), excessive body weight negatively affects the movement, such as walking and posture, but there are no experimental studies about GI and GT in these individuals. The aim of this study was to quantitatively characterise the strategy of patients with PWS during GI and GT using parameters obtained by the Center of Pressure (CoP) track.

METHODS

Twelve patients with PWS, 20 obese (OG) and 19 healthy individuals (HG) were tested using a force platform during the GI and GT tasks. CoP plots were divided into different phases, and duration, length and velocity of the CoP trace in these phases were calculated and compared for each task.

RESULTS

As for GI, the results showed a significant reduction of the task duration and lower velocity and CoP length parameters in PWS, compared to OG and HG. In PWS, those parameters were reduced to a higher degree with respect to the OG. During GT, longer durations, similar to OG, were observed in PWS than HG. Velocity is reduced when compared to OG and HG, especially in medio-lateral direction and in the terminal part of GT.

CONCLUSIONS

From these data, GI appears to be a demanding task in most of its sub-phases for PWS individuals, while GT seems to require caution only towards the end of the task. Breaking the cycle of gait into the phases of GI and GT and implementing specific exercises focusing on weight transfer and foot clearance during the transition phase from the steady condition to gait will possibly improve the effectiveness of rehabilitation and fall and injury prevention.

Effect of Cue Timing and Modality on Gait Initiation in Parkinson Disease With Freezing of Gait

OBJECTIVE

To examine the effects of cue timing, across 3 sensory modalities, on anticipatory postural adjustments (APAs) during gait initiation in people with Parkinson disease (PD).

DESIGN

Observational study.

SETTING

Biomechanics research laboratory.

PARTICIPANTS

Individuals with idiopathic PD (N=25; 11 with freezing of gait [FOG]) were studied in the off-medication state (12-h overnight withdrawal).

INTERVENTIONS

Gait initiation was tested without cueing (self-initiated) and with 3 cue timing protocols: fixed delay (3s), random delay (4-12s), and countdown (3-2-1-go, 1-s intervals) across 3 sensory modalities (acoustic, visual, and vibrotactile).

MAIN OUTCOME MEASURES

The incidence and spatiotemporal characteristics of APAs during gait initiation were analyzed, including vertical ground reaction forces and center of pressure.

RESULTS

All cue timings and modalities increased the incidence and amplitude of APAs compared with self-initiated stepping. Acoustic and visual cues, but not vibrotactile stimulation, improved the timing of APAs. Fixed delay or countdown timing protocols were more effective at decreasing APA durations than random delay cues. Cue-evoked improvements in APA timing, but not amplitude, correlated with the level of impairment during self-initiated gait. Cues did not improve the late push-off phase in the FOG group.

CONCLUSIONS

External cueing improves gait initiation in PD regardless of cue timing, modality, or clinical phenotype (with and without FOG). Acoustic or visual cueing with predictive timing provided the greatest improvements in gait initiation; therefore, these protocols may provide the best outcomes when applied by caregivers or devices.

Muscle synergies in preparation to a step made with and without obstacle

PURPOSE

To study multi-muscle synergies during preparation in making a step (self-paced level stepping vs. obstacle crossing stepping).

METHODS

The uncontrolled manifold hypothesis was used to explore the organization of leg and trunk muscles into groups (M-modes) and co-variation of M-mode involvement (M-mode synergies) during stepping tasks. Subjects performed two tasks: (1) making a comfortable step from quiet stance (STCS), (2) stepping over an obstacle of 15% body height from quiet stance, STOS. Electromyographic (EMG) signals of 10 postural muscles were recorded and analyzed. Principal component analysis was used to identify M-modes within the space of integrated indices of muscle activity. Variance in the M-mode space across stepping trials was partitioned into two components, one that did not affect the average value of center of pressure (COP) shift and the other that did. An index (ΔV) corresponding to the normalized difference between two components of variance was computed.

RESULTS

Under the two tasks, strong multi-M-mode synergies stabilizing trajectories of the COP in the anterior-posterior direction were found. Despite the significant differences in the COP shifts and EMG patterns of postural adjustments, the synergies showed only minor differences across the conditions.

CONCLUSIONS

These findings demonstrate the robustness of multi-M-mode synergies across different manners of making a step.

The kinematic control during the backward gait and knee proprioception: insights from lesions of the anterior cruciate ligament

An already existing large volume of work on kinematics documents a reduction of step length during unusual gaits, such as backward walking. This is mainly explained in terms of modifications of some biomechanical properties. In the present study, we propose that the proprioceptive information from the knee may be involved in this change of motor strategy. Specifically, we show that a non-automated condition such as backward walking can elicit different motor strategies in subjects with reduced proprioceptive feedback after anterior cruciate ligament lesion (ACL). For this purpose, the kinematic parameters during forward and backward walking in subjects with ACL deficit were compared to two control groups: a group with intact ACL and a group with surgically reconstructed ACL. The knee proprioception was tested measuring the threshold for detection of passive knee motion. Subjects were asked to walk on a level treadmill at five different velocities (1-5km/h) in forward and backward direction, thereby calculating the cadence and step length. Results showed that forward walking parameters were largely unaffected in subjects with ACL damage. However, they failed to reduce step length during backward walking, a correction that was normally observed in all control subjects and in subjects with normal proprioceptive feedback after ACL reconstruction. The main result of the present study is that knee proprioception is an important signal used by the brain to reduce step length during the backward gait. This can have a significant impact on clinical evaluation and rehabilitation.

Patients with advanced Parkinson's disease with and without freezing of gait: a comparative analysis of vascular lesions using brain MRI

INTRODUCTION

Freezing of gait (FOG) is one of the most disabling and enigmatic symptoms in Parkinson's disease. Vascular lesions, observed in magnetic resonance imaging (MRI) scans, may produce or exacerbate this symptom.

PATIENTS AND METHODS

The study includes 22 patients with Parkinson's disease subjects, 12 with freezing of gait and 10 without. All patients underwent an MRI scan and any vascular lesions were analysed using the modified Fazekas scale.

RESULTS

Patients with FOG scored higher on the modified Fazekas scale than the rest of the group. Although the two groups contained the same percentage of patients with vascular lesions (50% in both groups), lesion load was higher in the group of patients with FOG. Vascular lesions in the periventricular area and deep white matter seem to be the most involved in the development of FOG.

DISCUSSION

Vascular lesions may contribute to the onset or worsening of FOG in patients with PD. This study suggests that cerebral vascular disease should be considered in patients with FOG.

[A biomechanical analysis of cyclical hand motor function: a pilot study in different Parkinsonian syndromes]

INTRODUCTION

Clinical assessment of hand bradykinesia in Parkinson's disease (PD) focuses mainly on the frequency, amplitude and rhythm of movements, thereby subjectively evaluating the correct performance of hand movements. The aim of the study was to quantify hand bradykinesia with kinematic data in different Parkinsonian syndromes.

PATIENTS AND METHODS

This retrospective study compared patients with idiopathic PD (IPD, n = 18), atypical Parkinson's syndrome (APS, n = 17), secondary Parkinson's syndrome (SPS, n = 18) and healthy controls (C, n = 18). All patients were receiving the best medical treatment. Hand movements were recorded using an ultrasound-system (Zebris®, Isny, Germany). Subjects were asked to perform pronation/supination of the forearm (diadochokinesis), flexion/extension of the hand (hand tapping) and tapping of the index finger. Mean amplitude, mean frequency and mean variability of movements were determined.

RESULTS

APS patients had significant complex hand movement disability with reduced amplitude and frequency in combination with increased motion variability in all movement tasks. The key disturbance in the IPD group concerned the rhythm in hand tapping and index finger tapping in combination with moderately reduced velocity and range of motion in all conditions. The cyclical hand movement characteristics in SPS patients showed movement slowness with normal amplitude and variability in all motor conditions.

CONCLUSION

Our results suggest that computerized quantitative analysis of cyclical hand movements can characterize and identify different representations of hand bradykinesia in different Parkinsonian disorders and hence may help clinicians to accurately assess therapeutic targets and outcome of interventions.

Balance and gait problems in the elderly

Gait and balance problems are common with advancing age. Disorders of balance and gait are particularly important in the elderly because they compromise independence and contribute to the risk of falls and injury. Although they are considered as separate clinical entities, balance and gait disturbance are often intertwined. Here, we discuss the principal anatomical and physiologic mechanisms responsible for balance and gait. We also review the different types of fall patterns commonly seen in subjects and a classification scheme for various gait disorders. Furthermore, we consider the relationship between balance and gait disorders and subcortical vascular disease. Potential interventions and therapies in those individuals with balance and gait disorders are also discussed.

Frontal lobe ataxia

The precise anatomy and physiology of human walking remains poorly understood. The frontal lobes appear crucial, and, on the basis of clinical observation, contribute to the control of truncal motion, postural responses, and the maintenance of equilibrium and locomotion. The rich repertoire of frontal gait disorders gives some indication of this complexity. Variable combinations of disequilibrium with a wide stance base, increased body sway and falls, loss of control of truncal motion, locomotor disability with gait ignition failure, start hesitation, shuffling, and freezing are encountered in diseases of the frontal lobes. Furthermore, the pattern of gait may change as the frontal disease progresses. The slowness of walking, lack of heel-shin or upper limb ataxia, dysarthria or nystagmus distinguishes the wide stance base from cerebellar gait ataxia. A lively facial expression, normal voluntary movements of the upper limbs, upper motor neuron signs, and the absence of a rest tremor distinguish the hypokinetic elements from Parkinson's disease. Poor truncal mobility, impaired postural responses, and falls after the slightest perturbation eventually make walking impossible even though simple leg movements may still be possible while seated or lying. One or more of these features usually predominates in the initial presentation of a frontal gait syndrome. Accordingly, there is considerable variation in the manner of presentation and evolution of frontal gait disorders. The gait syndrome is accompanied by frontal motor and cognitive changes, which may be subtle or overshadowed by the gait disorder. This complexity of clinical presentation accounts for the plethora of descriptions from "frontal ataxia" to "gait apraxia". As suggested in the original descriptions of frontal ataxia, the spectrum of gait disturbance is likely to be due to damage to frontal cortex and its connections with subcortical structures including the basal ganglia, cerebellum, and the brainstem.

Does footwear type impact the number of steps required to reach gait steady state?: an innovative look at the impact of foot orthoses on gait initiation

Many studies have attempted to better elucidate the effect of foot orthoses on gait dynamics. To our knowledge, most previous studies exclude the first few steps of gait and begin analysis at steady state walking. These unanalyzed steps of gait may contain important information about the dynamic and complex processes required to achieve equilibrium for a given gait velocity. The purpose of this study was to quantify gait initiation and determine how many steps were required to reach steady state walking under three footwear conditions: barefoot, habitual shoes, and habitual shoes with a prefabricated foot orthoses. Fifteen healthy subjects walked 50m at habitual speed in each condition. Wearing habitual shoes with the prefabricated orthoses enabled subjects to reach steady state walking in fewer steps (3.5 steps+/-2.0) compared to the barefoot condition (5.2 steps+/-3.0; p=0.02) as well as compared to the habitual shoes condition (4.7 steps+/-1.6; p=0.05). Interestingly, the subjects' dynamic medial-lateral balance was significantly improved (22%, p<0.05) by using foot orthoses compared to other footwear conditions. These findings suggest that foot orthoses may help individuals reach steady state more quickly and with a better dynamic balance in the medial-lateral direction, independent of foot type. The findings of this pilot study may open new avenues for objectively assessing the impact of prescription footwear on dynamic balance and spatio-temporal parameters of gait. Further work to better assess the impact of foot orthoses on gait initiation in patients suffering from gait and instability pathologies may be warranted.

Knee trembling during freezing of gait represents multiple anticipatory postural adjustments

Freezing of gait (FoG) is an episodic, brief inability to step that delays gait initiation or interrupts ongoing gait. FoG is often associated with an alternating shaking of the knees, clinically referred to as knee trembling or trembling in place. The pathophysiology of FoG and of the concomitant trembling knees is unknown; impaired postural adjustment in preparation for stepping is one hypothesis. We examined anticipatory postural adjustments (APAs) prior to protective steps induced by a forward loss of balance in 10 Parkinson's disease (PD) subjects with marked FoG and in 10 control subjects. The amplitude and timing of the APAs were determined from changes in the vertical ground-reaction forces recorded by a force plate under each foot and were confirmed by electromyographic recordings of bilateral medial gastrocnemius, tibialis anterior and tensor fascia latae muscles. Protective steps were accomplished with a single APA followed by a step for control subjects, whereas PD subjects frequently exhibited multiple, alternating APAs coexistent with the knee trembling commonly observed during FoG as well as delayed, inadequate or no stepping. These multiple APAs were not delayed in onset and were of similar or larger amplitude than the single APAs exhibited by the control subjects. These observations suggest that multiple APAs produce the knee trembling commonly associated with FoG and that FoG associated with a forward loss of balance is caused by an inability to couple a normal APA to the stepping motor pattern.

Postural disorders in Parkinson's disease

Posture is often affected in Parkinson's disease. Postural abnormalities belong to the motor axial involvement. Generally, postural dysfunction induces clinical impairment at the latest stages of the disease, except in late-onset idiopathic Parkinson's disease and in atypical parkinsonian syndromes. Posture may be affected in its orientation component (stooped posture, camptocormia, Pisa syndrome) or in its balance component (loss of postural reflexes). Overall, postural impairment is poorly improved by levodopa, which implies that it is unlikely due to the nigrostriatal dopaminergic denervation. Several methods of investigation have been proposed but are generally not available in clinical practice. Medical treatment and deep brain stimulation (DBS) of the subthalamic nucleus or globus pallidus pars interna are less efficient on axial than on distal motor signs. The pedonculopontine nucleus seems promising as a new target for DBS in combination with the subthalamic nucleus. Physical therapy is, in most cases, the best way to improve postural dysfunction.

Delays in auditory-cued step initiation are related to increased volume of white matter hyperintensities in older adults

An increased volume of white matter hyperintensities (WMH) on MRI has been associated with mobility impairments in older adults. The objective of this preliminary study was to investigate the relationship between the volume of WMH and the delays in auditory-cued step initiation. Eight subjects aged 75-83 years participated. The WMH volume in the corticospinal tracts and anterior thalamic radiations were summed. Subjects performed an auditory-cued stepping task that included two simple reaction time (SRT) trials and three choice reaction time (CRT) trials. SRT trials required subjects to step as quickly as possible with the right foot from a symmetric standing position to a single target position in response to an auditory stimulus. For the CRT trials, subjects stepped as quickly as possible to one of two possible locations, depending on the auditory stimulus. The time from the stimulus onset to the reaction time of the anticipatory postural adjustment (APA(RT)) and liftoff (LO) of the right foot was computed for each stimulus. The mean APA(RT) and LO were greater for the CRT steps compared with the SRT steps to the same location. Increases in WMH were significantly associated with larger APA(RT) and LO during both SRT and CRT for both target locations. These data suggest that increased volume of WMH is associated with greater central processing time during voluntary step initiation, and highlight a possible mechanism that can help to explain how damage to white matter tracts affects mobility in older adults.

Postural preparation to making a step: is there a 'motor program' for postural preparation?

We tested the hypothesis that a sequence of mechanical events occurs preceding a step that scales in time and magnitude as a whole in a task-specific manner, and is a reflection of a "motor program." Young subjects made a step under three speed instructions and four tasks: stepping straight ahead, down a stair, up a stair, and over an obstacle. Larger center-of-pressure (COP) and force adjustments in the anterior-posterior direction and smaller COP and force adjustments in the mediolateral direction were seen during stepping forward and down a stair, as compared with the tasks of stepping up a stair and over an obstacle. These differences were accentuated during stepping under the simple reaction time instruction. These results speak against the hypothesis of a single motor program that would underlie postural preparation to stepping. They are more compatible with the reference configuration hypothesis of whole-body actions.

Higher level gait disorders

Higher level gait disorders are common in the elderly. The pathophysiology of these gait disorders is poorly understood, and the nomenclature used to describe them is confusing and the subject of ongoing debate. It is suggested that higher level gait disorders can be explained in terms of breakdown in the organization of equilibrium and locomotion.

Stepping from a narrow support

The study addresses postural preparation to stepping. In particular, it tests a hypothesis that such preparation involves adjustments in the activity of ankle plantarflexors to produce shifts of the center of pressure. We investigated the initiation of a step from quiet stance when the subjects stood on boards with a decreased dimension of the support area in the anterior-posterior direction ("unstable boards"). Stepping from an unstable board was associated with decreased preparatory shifts of the center of pressure (COP) in the anterior-posterior direction from about 3 cm to 0.9 cm and further to 0.1cm when the support narrowed from comfortable standing to 3.3 cm and to nearly 0 cm. There was a smaller decrease in the COP shift in the medio-lateral direction. When the subjects stood on a board which rested on a very narrow ridge ("zero-support"), they showed an increase in the magnitude of changes in the horizontal force immediately prior to making a step. There was a general increase in the level of activation of leg and trunk muscles during stepping from unstable boards. The modulation of the activity of ankle plantarflexors increased during stepping from unstable boards. We conclude that, to initiate a step, COP shifts and changes in shear force can be modulated independently of each other in a constraint-specific manner. The results speak against the hypothesis that modulation of ankle plantarflexor activity during postural adjustments is directly related to the production of COP shifts.

Gait initiation in children with cerebral palsy

The task of gait initiation (GI), or taking a first step from a static standing position requires the development of forward momentum while maintaining dynamic balance as the body's center of mass (COM) moves forward and outside the base of support. The dynamics of GI in children (aged 7-12 years) with hemiplegic cerebral palsy (CP), diplegic CP and children with typical development (TD) were compared to characterize the mechanics and control of this task. Ground reaction forces (GRFs) and muscle activity were collected during GI at three different self-selected speeds (slow, moderate and fast). Movement of a sacral marker was also tracked to estimate downward shifting of the body during the GI task. Results demonstrate the presence of a motor sequence characterized by increased forward momentum development with increased GI speed for all groups of children. Anticipatory movements of children with CP were different when compared to children with TD. Children with hemiplegic CP demonstrated decreased lateral shifting while children with diplegic CP demonstrated a trend of decreased downward shifting of the body compared to children of TD. Analysis of the GI motor sequence in children provides a means to characterize coordination and motor control of a functional ambulatory task in children with CP compared to children with TD.

Can falls be prevented in Parkinson's disease?

Patients with Parkinson's disease may benefit from a personalised exercise programme designed to help avoid falls and maintain mobility

Gait and dementia: moving beyond the notion of gait apraxia

Highest level gait disorders are produced by pathology in one or more structures in the cortical-basal ganglia-thalamocortical loop, which plays an important role in producing movements and postural synergies that meet personal desires and environmental constraints. Virtually all patients with dementia have pathology in one or more components of this loop, so highest level gait disorders are common in patients with dementia. The terminology surrounding these gait disorders is unnecessarily complex and too heavily influenced by the controversial concept of gait apraxia. Straightforward descriptive diagnostic criteria are needed. To this end, four core clinical features of highest level gait disorders are proposed: 1) inappropriate (counterproductive) or bizarre limb movement, postural synergies, and interaction with the environment, 2) qualitatively variable performance, influenced greatly by the environment and emotion, 3) hesitation and freezing, and 4) absent or inappropriate (counterproductive) rescue reactions. These core features follow logically from the physiology of the cortical-basal ganglia-thalamocortical loop and should be regarded as signs of pathology in this loop. A clinical rating scale based on these features should be developed to facilitate clinical diagnosis and clinicopathological correlation, while avoiding the ambiguities and controversies of gait apraxia.

Higher level gait disorders

This short review is derived from the contributions of the authors at a meeting on gait disorders and higher mental function held in Madrid in February 2006 and is submitted at the request of the meeting convenor, Dr N Giladi.

Bilateral subthalamic stimulation improves gait initiation in patients with Parkinson's disease

Impaired gait initiation is one of the typical sign of advanced Parkinson's disease (PD). This is the first study to examine quantitatively the effect of deep brain stimulation of the subthalamic nucleus on the performance of gait initiation for patients with advanced PD. A total of 11 patients after surgery of bilateral deep brain stimulation of the subthalamic nucleus (STN) were tested in both the deep brain stimulation (DBS) ON and OFF conditions and/or in both the medication ON (i.e., with the usual dosage of antiparkinsonian medications administered) and OFF (i.e., with the usual dosage of antiparkinsonian medications withheld) conditions. DBS had no effect on the onset of anticipatory postural adjustment (APA). The effect of DBS approached significant level for the onset of swing foot lifting, but reached significant level for the delay of swing foot lifting. DBS significantly increased the amplitude of the APA, amplitude of reactive shear forces on both feet, and amplitude of COP in both anterior-posterior and medial-lateral directions. It is concluded that DBS significantly improved the performance of patients with advanced PD in gait initiation.

Effects of visual and auditory cues on gait initiation in people with Parkinson's disease

OBJECTIVE

To evaluate the effects of auditory and visual cues on gait initiation in people with Parkinson's disease.

SUBJECTS

Fourteen subjects with Parkinson's disease were recruited from community support groups, seven of whom reported having experienced freezing when walking.

DESIGN AND SETTING

This study was a repeated measures analysis of gait initiation performance during a single visit to a university-based motion laboratory. Following baseline trials, auditory and visual cue conditions were presented in random order. The auditory cues were rhythmic sounds with an interval matching the subject's average step time. The visual cues were high-contrast transverse lines on the floor adjusted for the subject's first step length and overall height.

MAIN MEASURES

Kinematic recordings enabled calculation of the timing and length of steps as well as overall velocity. The timing and magnitude of weight shift and push-off force were obtained from a force platform.

RESULTS

The magnitudes of first and second step lengths, of push-off force and of overall gait velocity were significantly greater in the visual cue condition than in the baseline condition, whereas there was no significant effect of auditory cue on these measures. Neither cue had any significant effect on the timing of key events in gait initiation.

CONCLUSIONS

Transverse line visual cues enable people with Parkinson's disease to begin walking with longer steps, greater push-off force and higher velocity. Auditory cues that others have shown to improve aspects of gait in people with Parkinson's disease do not appear to have any systematic effect on the first two steps of gait initiation.

Three-dimensional stereotactic surface projection study of freezing of gait and brain perfusion image in Parkinson's disease

Gait disturbance is a cardinal symptom in patients with Parkinson's disease. Among the gait disturbances, freezing of gait is a unique and troublesome symptom, but its mechanism is unclear. We compared brain perfusion images using three-dimensional stereotactic surface projection analysis of N-isopropyl-p-123I iodoamphetamine single photon emission computed tomography between Parkinson's disease patients with freezing of gait and those without. Twenty-four cases (freezing of gait group) with Parkinson's disease with freezing of gait, and 31 Hoehn and Yahr stage-matched cases (no freezing of gait group) with Parkinson's disease without freezing of gait were studied. Bilateral Brodmann area 11 perfusion of the freezing of gait group decreased significantly compared to that of the no freezing of gait group. The Brodmann area 11 may play important roles in gait, and impairment in this region may have a close relationship with freezing of gait in Parkinson's disease.

Quantitative assessments of the effect of bilateral subthalamic stimulation on multiple aspects of sensorimotor function for patients with Parkinson's disease

Deep brain stimulation (DBS) of the subthalamic nucleus (STN) is effective for the treatment of advanced Parkinson's disease. Most studies have evaluated the effectiveness of DBS of the STN using clinical motor scores or simple timed tests of motor function. There have been few studies that quantitatively assessed the outcome of STN DBS using multiple testing paradigms. In the current study, 11 patients who had bilateral STN DBS were quantitatively evaluated under four conditions using gait, postural control, and gait initiation. The four conditions included the medication on/stimulation on (M_on/S_on), medication on/stimulation off (M_on/S_off), medication off/stimulation on (M_off/S_on), and medication off/stimulation off (M_off/S_off) conditions. DBS of the STN significantly increased walking speed with and without levodopa, but had no influence on the cadence. The addition of levodopa had a minimal additional effect on walking speed. The effect of STN DBS on gait initiation approached the significant level. The mean values of lateral body sway during quiet standing increased moderately with medication and/or DBS, but the changes were not statistically significant. Future studies need to determine whether or not there is a potential negative effect of STN DBS on the postural control.

Different clinical and evolutional patterns in late idiopathic and vascular parkinsonism

OBJECTIVE

The aim of this study was to examine the clinical picture of Parkinson's disease (PD) and vascular parkinsonism (VP) in the elderly, in an attempt to differentiate the clinical history, symptoms, signs and response to therapy.

MATERIAL AND METHODS

Thirty-two elderly patients with late onset PD and 45 with VP were enrolled and the clinical features of two groups were compared. All patients underwent brain MRI and were scored using the Unified Parkinson's Disease Rating Scales (UPDRS) -II, -III.

RESULTS

Patients with PD had a younger age at onset and a longer duration of the disease as compared to patients with VP. Nearly all PD patients showed a good response to levodopa therapy, while only 29% of patients with VP were responsive to levodopa treatment. Vascular risk factors as well as postural tremor, gait disorders and pyramidal signs with lower body predominance, were more frequent in patients with VP. Ninety-three % of PD patients had normal MRI, whereas all patients with VP had cerebral vascular lesions. UPDRS-II, -III scores at baseline were higher in VP than in PD patients and their increases throughout the follow-up period were more marked in VP than in PD patients.

CONCLUSIONS

Clinical history, symptoms, signs, response to therapy, and brain imaging help to differentiate PD and VP as two clinical entities with different clinical, prognostic and therapeutic implications, even if the coexistence of PD and a cerebral vascular disease in elderly patients is not infrequent and can make the diagnosis difficult.

Apraxia in movement disorders

The definition of apraxia specifies that the disturbance of performed skilled movements cannot be explained by the more elemental motor disorders typical of patients with movement disorders. Generally this does not present a significant diagnostic problem when dealing with 'higher-level' praxic disturbances (e.g. ideational apraxia), but it can be a major confound in establishing the presence of limb-kinetic apraxia. Most motor disturbances characteristic of extrapyramidal disorders, particularly bradykinesia and dystonia, will compromise the ability to establish the presence of loss of dexterity and deftness that constitutes this subtype. The term 'apraxia' has also been applied to other motor disturbances, such as 'gait apraxia' and 'apraxia of eyelid opening', that perhaps are misnomers, demonstrating the lack of a coherent nomenclature in this field. Apraxia is a hallmark of corticobasal degeneration (CBD) and historically this has received the most attention among the movement disorders. Corticobasal degeneration is characterized by various forms of apraxia affecting limb function, particularly ideomotor apraxia and limb-kinetic apraxia, although buccofacial and oculomotor apraxia can be present as well. The syndrome of parkinsonism and prominent apraxia, designated the 'corticobasal syndrome' (CBS), may be caused by a variety of other central nervous system pathologies including progressive supranuclear palsy (PSP), Alzheimer's disease, dementia with Lewy bodies and frontotemporal dementias. Distinct from the CBS, PSP and Parkinson's disease can demonstrate varying degrees of apraxia on selected tests, especially in those patients with more severe cognitive dysfunction. Diseases that cause the combination of apraxia and a primary movement disorder most often involve a variety of cerebral cortical sites as well as basal ganglia structures. Clinical-pathological correlates and functional imaging studies are compromised by both this diffuse involvement and the confusion experienced in the clinical evaluation of apraxia in the face of the additional elemental movement disorders. Finally, although apraxia results in clear disability in patients with the CBS, it is not clear how milder ideomotor apraxia found on specific testing contributes to patients' overall day-to-day motor disability.

From trepidant abasia to motor network failure--gait disorders as a consequence of subcortical vascular encephalopathy (SVE): review of historical and contemporary concepts

Gait disorders in progressive subcortical vascular encephalopathy (SVE) and their impact on the burden of disability in the growing elderly population are underrepresented in medical scientific literature. The absence of a clear framework for the diagnosis and classification for gait disorders on the basis of SVE has multiple reasons: (1) neither movement disorder specialists nor stroke specialists are truly familiar with this topic and feel responsible for its treatment, (2) the existing terminology lacks a clear concept and a consistent classification, and (3) only in recent years have large prospective trials started to address the natural course of SVE. This article reviews the classical descriptions of gait disturbances with preferential view to our present concept of SVE, and comments on historical and current nosology of gait disorders aiming to propose for a new classification.

Temporal differences in relative phasing of gait initiation and first step length in patients with cervical and lumbosacral spinal cord injuries

STUDY DESIGN

Comparison group design.

OBJECTIVE

To compare the temporal distance factors during gait initiation between patients with incomplete cervical spinal cord injury, incomplete lumbosacral spinal lesion, and unimpaired control adults.

SETTING

Human performance and movement analysis laboratory, Taiwan.

PARTICIPANTS

Five patients with an incomplete cervical spinal cord injury (Group 1), five patients with an incomplete lumbosacral spinal lesion (Group 2) and nine unimpaired control adults (Group 3).

METHODS

Subjects underwent a three-dimensional gait analysis. The total gait initiation period, reaction time, each relative phasing of gait initiation and the length of the first step were identified by using the kinematic measurement system.

MAIN OUTCOME MEASURES

The total gait initiation period (start of the auditory cue for gait initiation to heel-strike of the first swing leg); each relative phasing of gait initiation indicated that the duration of the preparatory phase (start of auditory cue for gait initiation to heel-off of the first swing leg), the duration of the push-up phase (heel-off to toe-off of the first swing leg), and the duration of the single-stance phase (toe-off to heel-strike of the first swing leg) established by the total gait initiation period; and the length of the first step.

RESULTS

The gait initiation period was greater in Groups 1 and 2 than that of Group 3 (P<0.05). Each relative phasing including the duration of the preparatory phase, the push-up phase, and the swing phase relative to the total gait initiation period, did not differ among Groups 1-3 (P>0.05). The length of the first step, measured while the nonpreferred leg stepped first in Groups 1 and 2, was shorter than that of Group 3 (P<0.05).

CONCLUSIONS

Patients with incomplete cervical spinal cord injuries or lumbosacral spinal lesions took more time in gait initiation than unimpaired control adults. The first step length also reduced in these patients while the nonpreferred leg stepped first, as compared to unimpaired control adults. The data indicated that centrally programmed gait initiation might be preserved in ASIA-D spinal patients who, in this study, executed gait initiation with varying temporal distance strategies to compensate for peripheral impairments, as compared to unimpaired control adults.

Muscle activity during gait initiation in normal elderly people

The purpose of this study was to describe the patterns of phasic muscle during gait initiation in normal elderly people. Bilateral surface EMG recordings were made of tibialis anterior, medial gastrocnemius and gluteus medius activity throughout gait initiation in 21 subjects. A variable expression of the onset muscle pattern is shown, with a tendency for muscle activity to be more variable in the preparatory phase. These results provide a baseline of normal gait initiation muscle activity against which to compare that of patients with gait initiation and balance difficulties.

Coordination of axial rotation and step execution: deficits in Parkinson's disease

To determine why parkinsonian patients (PP) present some difficulties to initiate locomotion, a diagonal step has been investigated in two tasks in five control subjects (CS) and in ten PP. In the first task, the subjects had to perform one diagonal step without change in their orientation (WR); in the second task, they had to perform one diagonal step with a body rotation in the step direction (RO). The defended hypothesis is that the gait initiation deficits in Parkinson disease are a consequence of their difficulties to coordinate al the component of a complex movement. The analysed parameters were the duration of the postural and movement phases, the step length and velocity, and the amplitude of the horizontal ground reaction forces during each phase. Compared to CS, the PP showed a lengthening of the postural phase, a decrease in the step length and velocity and a reduction of the horizontal forces. The comparisons between the performances obtained in the WR versus those obtained the RO show in CS that the performances remained unchanged, whereas in PP the performances were significantly more altered in the RO. It illustrates the specific deficit occurring in PP while performing complex tasks where coordination between several components has to be achieved simultaneously.

Atypical antipsychotics in Parkinson-sensitive populations

Drug-induced iatrogenic hallucinations and psychosis occur in about 30% of Parkinson's disease (PD) patients and are the single most important precipitant for nursing home placement, which carries a grave prognosis. In addition, parkinsonism is a frequent accompaniment to the more common dementing syndromes, Alzheimer's disease (AD), vascular dementia, and dementia with Lewy bodies (DLB). The five most recent antipsychotic drugs approved by the Food and Drug Administration in the United States have been marketed as "atypical" antipsychotics (AA) due to their relative freedom from extrapyramidal symptoms when used in schizophrenia patients. The use of these newer antipsychotic drugs in PD and other parkinson-sensitive populations represents the most stringent test to their freedom from motor side effects. To date, clozapine, risperidone, olanzapine, and quetiapine have been studied in parkinson-vulnerable populations. This article reviews the data and highlights the differences that these four drugs have on motor function. It also emphasizes the challenges in evaluating the available data on the motor effects of AA, especially on the non-PD elderly and cognitively impaired population. Suggestions are made for future research to improve the interpretability of these studies.

Switching of movement direction is central to parkinsonian bradykinesia in sit-to-stand

Patients with Parkinson's disease (PD) are known to manifest slowness in movements. We sought to identify the particular kinematic and kinetic disorders that contribute to the slowness in performing sit-to-stand in these patients. Two inter-related studies were carried out. In the first study, 20 patients with PD and 20 control subjects were instructed to perform sit-to-stand at a natural speed. In the second study, 15 control subjects were instructed to simulate the slower speed of sit-to-stand of the patients identified in the first study. Kinematic and kinetic data were recorded by a PEAK motion analysis system and two force platforms. The results showed that patients with PD generated smaller peak horizontal and vertical velocities during the task. They took a longer time to complete each individual phase as well as the whole movement of sit-to-stand. Patients also produced smaller peak hip flexion and ankle dorsiflexion joint torques and had prolonged time-to-peak torques from sit-to-stand onset. When control subjects simulated the patients' speed of sit-to-stand, there was no difference in all the kinematic and kinetic data between groups. The only exception was that they exhibited a shorter transition time between peak horizontal velocity (flexion phase) and seat-off (extension phase) than the patients. This study demonstrated that the slowness of PD patients during sit-to-stand at a natural speed could be attributed to inadequate peak hip flexion and ankle dorsiflexion torques, a prolonged torque production, as well as a difficulty in switching from the flexion to extension direction during sit-to-stand. As the latter difficulty persisted when the control subjects performed the task at a speed similar to that of the patients, our findings suggest that a fundamental problem of patients with Parkinson's disease could be a switch between movement directions.

Anticardiolipin antibody in vascular parkinsonism

Vascular parkinsonism (VP) is characterized by predominantly lower body involvement with gait impairment and postural instability, often without tremor, and by relative levodopa unresponsiveness. Neuroimaging studies demonstrate multiple infarcts or ischemic changes in periventricular white matter. Anticardiolipin antibodies (ACLA) are associated with hypercoagulable states and increased stroke risk. Review of our Movement Disorders Clinic records identified 44 individuals with a diagnosis of VP. ACLA have been obtained in 22 of these patients (mean age, 78.3 years; mean Mini-Mental Status Exam score, 25.8). Gait disturbance was the initial clinical feature in 82% of the patients, and levodopa responsiveness was present in 18% of those treated. In 9 of the 22 (40.9%), ACLA immunoglobulin G was positive. No significant differences in clinical features or risk factors (hypertension, diabetes, coronary artery disease, and clinical stroke) were evident between ACLA+ and ACLA- groups. Since the presence of ACLA in individuals with stroke is usually treated by full-scale anticoagulation with warfarin, our findings raise the question whether such treatment should also be used in persons with VP who are ACLA positive.