Dual-tasks and walking fast: relationship to extra-pyramidal signs in advanced Alzheimer disease

Extra-pyramidal signs (EPS) and cadence predicted falls risk in patients with advanced Alzheimer disease (AD). Dual task performance predicts falls with variable success. Dual-task performance and walking fast were examined in advanced AD patients with EPS (EPS+, >3 modified Unified Parkinson's Disease Rating Scale [UPDRS] signs) or without EPS (EPS-, three or less UPDRS signs). Demographics, mental and functional status, behavioral impairment, EPS, and quantitative gait measures (GaitRite) were determined. The effects of an automatic dual-task (simple counting) and of walking fast on spatial and temporal gait characteristics were compared between EPS+ and EPS- subjects using a repeated measures design. Cadence decreased, while stride time, swing time and variability in swing time increased with the dual task. Results were insignificant after adjusting for secondary task performance. With walking fast, speed, cadence and stride length increased while stride time, swing time and double support time decreased. Although EPS+ subjects were slower and had decreased stride length, dual task and walking fast effects did not differ from EPS- subjects. Patient characteristics, the type of secondary task and the specific gait measures examined vary in the literature. In this moderately to severely demented population, EPS did not affect "unconscious" (dual task) or "conscious" (walking fast) gait modulation. Given their high falls risk, and retained ability to modulate walking, EPS+ AD patients may be ideal candidates for interventions aimed at preventing falls.     

Locomotion speed determines gait variability in cerebellar ataxia and vestibular failure

Temporal gait variability is a critical parameter in patients with balance problems. Increased magnitude of temporal gait variability corresponds to a higher risk of falls. The purpose of this study was to investigate the influence of walking speed on temporal stride-to-stride variability in patients with cerebellar and vestibular deficits. A GAITRite system was used to analyze the gait of 40 patients with cerebellar ataxia, 22 patients with bilateral vestibular failure, and 51 healthy subjects over the entire range of the individual's speed capacity. The coefficient of variability of stride time was calculated for each walk. Temporal gait variability was increased in cerebellar patients and vestibular patients. The magnitude of this variability depended on walking speed in a disease-specific manner. In patients with cerebellar ataxia, variability was increased during slow (8.4 ± 5.3%, P < .01) and fast (7.9 ± 6.4%, P < .01) walking speed but was normal during preferred walking speed. This resulted in a speed-related U-shaped function of stride-time variability. Patients with vestibular failure had increased variability during slow walking (9.9 ± 4.3%, P < .01). During walking with medium and fast walking speed, stride time variability was normal. Minimal temporal gait variability appears to be attractive for the locomotor system in cerebellar patients because these patients preferred to walk at a velocity associated with minimal stride-time variability. In contrast to previous studies, vestibular patients accelerate rather than decelerate gait to achieve dynamic stability. This may be explained by reduced sensory integration during fast locomotion.     

Treadmill walking as an external pacemaker to improve gait rhythm and stability in Parkinson's disease.

Recent reports suggest that external cueing improves stride length and gait speed in Parkinson's disease (PD). The purpose of the present study was to examine the influence of treadmill walking on gait variability. The 36 PD patients (Hoehn and Yahr stage 2--2.5) were compared to 30 controls. Subjects walked three times for 2 minutes each: (1) walking on level ground (unassisted), (2) walking on level ground while using a walker, and (3) walking on a treadmill. Stride time variability and swing time variability were significantly increased in the patients compared to the control subjects when walking on level ground with a walker. In both groups, the use of a walking aid did not significantly affect stride time variability or swing time variability, but the treadmill reduced stride time variability and swing time variability in the patients and in the controls. These results indicate that, during treadmill walking, PD subjects are able to walk with a less variable and more stable gait. Because the treadmill walking speed was set to the gait speed on level ground and because this effect was not seen with a walking aid, we suggest that the treadmill may be acting as an external cue to enhance gait rhythmicity and reduce gait variability.     

Evidence for a disorder of locomotor timing in Huntington's disease.

Disturbances of walking have been described in people with Huntington's disease (HD), although the nature of the deficits have not yet been well defined. The purpose of this investigation was to determine whether people with HD have a deficit in the regulation of footstep timing during walking. The footstep patterns of 30 people with HD and 30 matched comparisons were measured at self-selected slow, preferred, and fast speeds. Subjects were also instructed to match their footsteps to auditory metronome cues set at 80 and 120 beats per minute. Gait speed, cadence, stride length, and double limb support as a percentage of the gait cycle were measured using a computerized foot-switch system. People with HD demonstrated a disorder in their ability to regulate cadence, manifest as a reduced step frequency when walking at preferred speed and when required to increase their speed. For all walking conditions, people with HD had increased variability of footstep cadence. They also had difficulty synchronizing their footstep timing to an auditory cue. For all walking conditions, people with HD had reduced stride length. Thus, in HD, there is a disorder in the regulation of footstep timing, with increased variability, a restricted cadence range, difficulty synchronizing footsteps to an auditory cue and reduced stride length. The exact neural correlates of this timing disorder are yet to be determined.     

Ability to modulate walking cadence remains intact in Parkinson''s disease.

Gait hypokinesia (slowness) is a characteristic feature of Parkinson's disease. It is not clear, however, whether the slowness is due to a problem in regulation of the timing of consecutive steps or the control of stride size. Examination of cadence control for slow to medium walking speeds has shown an increase in step frequency that was a compensation for reduced stride length. In this investigation the ability of Parkinsonian patients to modulate their cadence (steps per minute) at the fast walking speeds exhibited by age and height matched controls was examined. The findings indicated that cadence control remains unaffected throughout its entire range in Parkinson's disease and that gait hypokinesia is directly attributable to an inability to internally generate sufficiently large steps.     

双任务步行对缺血性卒中患者认知-运动干扰的影响研究

目的 探讨缺血性卒中患者和健康人在进行双任务步行(dual-task walking,DTW)时,不同认知任务对步态和认知-运动干扰(cognitive-motor interference,CMI)的影响.方法 选取24例急性缺血性卒中患者为卒中组,并选取与卒中组性别、年龄、受教育程度相匹配的16例健康志愿者为对照组...     

弹性悬带矫形器对偏瘫患者步行功能的影响

目的 评价新型弹力悬带矫形器对患者下肢运动功能及步行功能恢复的效果。方法 28例卒中后偏瘫患者随机被纳入康复治疗组（对照组）和弹力悬带矫形器治疗组（治疗组）,对照组在治疗师指导下进行常规康复训练,治疗组在常规康复训练的基础上佩带弹力悬带矫形器进行步行训练,连续治疗8周。分别于治疗前,治疗后4周和治疗后8周由同一个治疗师对下肢运动功能评分（Fugl-Meyer,FMA）、能量消耗指数（physical consume index,PCI）及包括10 m舒适步行速度和10 m快速步行速度、步频、步长、足偏角、步基宽在内的步态时空参数进行评测,并比较上述指标在治疗前后的变化,观察弹力悬带矫形器的作用效果。结果 治疗4周后,治疗组和对照组10 m舒适步行速度和10 m快速步行速度、步长、步频较治疗前提高（均P＜0.01）,步基宽、PCI较治疗前降低（均P＜0.01）;2组FMA和足偏角治疗前后差异无统计学意义。治疗后治疗组10 m舒适步行速度和10 m快速步行速度、步长较对照组明显提高（P =0.0298,0.0225,0.025）,步基宽、PCI较对照组明显降低（P =0.001,0.026）;2组步频、FMA和足偏角比较差异无统计学意义。治疗8周后,治疗组和对照组的10 m舒适步行速度和10 m快速步行速度、步长、步频及FMA评分较治疗前提高（均P＜0.01）,步基宽、PCI较治疗前降低（均P＜0.01）;2组足偏角治疗前后差异无统计学意义。治疗后治疗组10 m舒适步行速度和10 m快速步行速度、步长、步频及FMA评分较对照组明显提高（P =0.042、0.015,0.024,0.024,0.038）,步基宽、PCI较对照组明显降低（均P＜0.01）;2组足偏角比较差异无统计学意义。结论 早期使用弹力带矫形器可以纠正偏瘫患者的异常步态,提高步行速度,降低能量消耗,促进步行功能恢复。     

Changes in gait and fatigue from morning to afternoon in people with multiple sclerosis

OBJECTIVES: The aim was to measure changes in walking patterns and self rated fatigue in people with multiple sclerosis (MS) compared with age matched control subjects, from the morning to the afternoon within a single day. METHODS: Fourteen patients with MS and the same number of matched control subjects performed four 10 m gait trials at their preferred walking speed at 10 00 am and then again at 3 00 pm on the same day. Gait speed, stride length, cadence, and the percentage of the gait cycle spent in double limb support were measured using a foot switch stride analyzer. Patients with MS also self rated their fatigue levels in the morning and afternoon using an 11 point scale. RESULTS: Compared with control subjects, patients walked very slowly, with reduced stride length and around twice as much variability in gait performance. Although self rated fatigue significantly increased from the morning to the afternoon, walking patterns remained consistent in both groups over the course of the day. CONCLUSIONS: These findings imply that mechanisms controlling locomotion are separate from those regulating perceived fatigue. Objective measures of performance, rather than self report, should be used to monitor change in patients with multiple sclerosis.     

Walking stability using harmonic ratios in Parkinson's disease

Kinematic changes in Parkinson's disease (PD) gait are well documented; however, upper body dynamics are less understood. Harmonic ratios (HRs) measure the rhythm of trunk accelerations and can be examined in the vertical, anterior‐posterior, and mediolateral planes, providing an indication of global walking stability (lower HR indicates poorer stability). We examined differences in HRs between persons with PD and healthy older adults and relationships between HRs and stride parameters. Eleven people with PD and 11 older adults walked over ground at their preferred pace. A triaxial accelerometer measured trunk accelerations. HRs and spatiotemporal parameters were calculated and standardized to remove the influence of gait velocity. The PD group exhibited lower HRs in all three planes, with the most pronounced differences in the mediolateral and anterior‐posterior planes. Greater stride time variability was most closely associated with a lower anterior‐posterior HR in PD and the presence of disease with the mediolateral HR. By demonstrating decreased walking stability in medial‐lateral and anterior‐posterior planes, we conclude that HRs offer unique information beyond that of typical stride parameters, and stride time variability is most closely associated with these direct measures of global walking stability. © 2008 Movement Disorder Society     

Rhythmic auditory stimulation modulates gait variability in Parkinson's disease

Patients with Parkinson's disease (PD) walk with a shortened stride length and high stride-to-stride variability, a measure associated with fall risk. Rhythmic auditory stimulation (RAS) improves stride length but the effects on stride-to-stride variability, a marker of fall risk, are unknown. The effects of RAS on stride time variability, swing time variability and spatial-temporal measures were examined during 100-m walks with the RAS beat set to 100 and 110% of each subject's usual cadence in 29 patients with idiopathic PD and 26 healthy age-matched controls. Carryover effects were also evaluated. During usual walking, variability was significantly higher (worse) in the patients with PD compared with the controls (P < 0.01). For the patients with PD, RAS at 100% improved gait speed, stride length and swing time (P < 0.02) but did not significantly affect variability. With RAS at 110%, reductions in variability were also observed (P < 0.03) and these effects persisted 2 and 15 min later. In the control subjects, the positive effects of RAS were not observed. For example, RAS increased stride time variability at 100 and 110%. These results demonstrate that RAS enables more automatic movement and reduces stride-to-stride variability in patients with PD. Further, these improvements are not simply a by-product of changes in speed or stride length. After walking with RAS, there also appears to be a carryover effect that supports the possibility of motor plasticity in the networks controlling rhythmicity in PD and the potential for using RAS as an intervention to improve mobility and reduce fall risk.     

Energy cost of spontaneous walking in Parkinson’s disease patients

In healthy subjects, comfortable walking minimizes the energy cost (E (c)) of locomotion. In Parkinson's disease (PD) patients walking is slower than in healthy subjects: this may increase E (c). Our aims were to analyze gait and E (c) in PD patients during walking, particularly at self-selected speed, and the possible pathological, mechanical, and cardiorespiratory limitations. Fourteen mild-to-moderate PD and 14 control subjects were enrolled. Subjects underwent 5-min walking tests at two speeds: self-selected and as-fast-as-possible speeds. Cardiopulmonary and gait parameters (heart rate, ventilation, gas exchanges, step count) were recorded. Velocity was reduced in PD compared to control subjects at both speeds (P < 0.05), and PD patients had shorter strides (P < 0.05) at both speeds and reduced cadence (P = 0.01) at fastest speed. No significant difference was found in E (c) at self-selected (0.12 ± 0.04 versus 0.11 ± 0.02 mLO(2) kg(-1) m(-1) in PD and control subjects, respectively) and maximal (0.14 ± 0.03 versus 0.15 ± 0.02 mLO(2) kg(-1) m(-1) in PD and control subjects, respectively) speed. However, the E (c) increment from self-selected to fastest velocity was significantly lower (P = 0.02) in PD patients. PD patients failed to walk at a self-selected speed, which minimizes the E (c). This could be mainly due to the inability to develop a wider stride. Cardiorespiratory adaptation was not affected, except for the possible reduced cardiac adaptation observed in some (28%) cases. Presumably, rehabilitation procedures that improve flexibility and step length may help maintain walking ability.     

Role of attentional resources on gait performance in Huntington's disease

Patients with Huntington's disease (HD) suffer from cognitive deficits with impaired executive functions, including limited attentional resources. We sought to use a dual‐task paradigm to evaluate attentional demands and the ability of patients with HD to concentrate on two tasks simultaneously. We analyzed the interference effects of cognitive and motor tasks on walking in HD and the contribution of clinical symptoms to gait disturbances. Patients and controls were asked to perform either a motor task (carrying a tray with four glasses), a cognitive task (counting backwards), or no task at all while walking at their preferred speed. Kinematic spatial parameters, temporal parameters, and angular parameters related to gait were recorded in 15 patients and 15 controls by means of a videomotion analysis system. Gait instability was assessed using the stride‐to‐stride variability of the various gait parameters. For patients with HD, performing a concurrent cognitive task resulted in a lower gait speed (compared with free walking), with decreased cadence and stride length. However, this effect was not observed in controls. Performing a motor task did not change any kinematic gait parameters in either HD or control subjects. We found correlations between gait speed in the dual cognitive/walking task on one hand and the motor UHDRS score, cognitive status and executive function on the other. Patients with HD had greater difficulty walking while performing a concurrent cognitive task; the drain on attentional resources deteriorated walking performance. © 2007 Movement Disorder Society     

Assessment of dual tasking has no clinical value for fall prediction in Parkinson’s disease

The objective of this study is to investigate the value of dual-task performance for the prediction of falls in patients with Parkinson’s disease (PD). Two hundred sixty-three patients with PD (H&Y 1–3, 65.2?±?7.9?years) walked two times along a 10-m trajectory, both under single-task and dual-task (DT) conditions (combined with an auditory Stroop task). To control for a cueing effect, Stroop stimuli were presented at variable or fixed 1- or 2-s intervals. The auditory Stroop task was also performed alone. Dual-task costs were calculated for gait speed, stride length, stride time, stride time variability, step and stride regularity, step symmetry and Stroop composite scores (accuracy/reaction time). Subsequently, falls were registered prospectively for 1?year (monthly assessments). Patients were categorized as non-recurrent fallers (no or 1 fall) or recurrent fallers (>1 falls). Recurrent fallers (35%) had a significantly higher disease severity, lower MMSE scores, and higher Timed “Up & Go” test scores than non-recurrent fallers. Under DT conditions, gait speed and stride lengths were significantly decreased. Stride time, stride time variability, step and stride regularity, and step symmetry did not change under DT conditions. Stroop dual-task costs were only significant for the 2-s Stroop interval trials. Importantly, recurrent fallers did not show different dual-task costs compared to non-recurrent fallers on any of the gait or Stroop parameters. These results did not change after correction for baseline group differences. Deterioration of gait or Stroop performance under dual-task conditions was not associated with prospective falls in this large sample of patients with PD.     

双任务步行对缺血性卒中患者步态参数影响的研究

目的 探讨双任务步行（dual-task walking,DTW）对缺血性卒中患者步态参数的影响。 方法 前瞻性入组2020年6月-2021年3月于首都医科大学附属北京天坛医院康复科住院的缺血性 卒中患者。选择时钟任务作为DTW中的认知任务,受试者依次完成单任务步行（single-task walking, STW）和DTW。使用Codamotion三维动作捕捉系统采集患者执行任务时步态的运动学参数（膝关节、踝 关节活动范围、最大屈膝角度、最大伸膝角度、最大踝背屈角度、最大踝跖屈角度）和时空参数（步 速、跨步长、跨步时间、跨步速度、步长、步长时间、步频、支撑期百分比）,计算时空参数的变异系数。 比较患者进行STW和DTW时上述步态参数的差异。 结果 本研究共纳入28例缺血性卒中患者,男性20例（71.4%）。患者进行STW和DTW时步态的 运动学参数差异无统计学意义。在时空参数方面,与STW时相比,进行DTW时患者的步速降低 （0.69±0.23 m/s vs 0.80±0.27 m/s,P＜0.001）、步长（0.41±0.11 m vs 0.46±0.12 m,P＜0.001）和跨 步长缩短（0.85±0.20 m vs 0.95±0.22 m,P＜0.001）。在时空参数变异性方面,与STW比较,卒中患 者进行DTW时步长时间变异性[4.47（2.98～7.34）vs 2.58（1.76～4.27）,P＝0.013]及步频变异性[4.59 （2.78～7.78）vs 2.71（1.84～4.44）,P＝0.020]增加。 结论 卒中患者在进行DTW时更容易发现步态问题。与STW相比,双任务条件下的步态评估可能是 更有效的卒中康复评估指标,也更适用于卒中后康复训练计划。     

Exploring effects of different treadmill interventions on walking onset and gait patterns in infants with Down syndrome

Two cohorts of participants were included to investigate the effects of different treadmill interventions on walking onset and gait patterns in infants with Down syndrome (DS). The first cohort included 30 infants with DS (17 males, 13 females; mean age 10 mo [SD 1.9 mo]) who were randomly assigned to either a lower-intensity-generalized (LG) training group, or a higher-intensity-individualized (HI) training group. A control (C) group from another study, who did not receive treadmill training, served as the control (eight males, seven females; mean age 10.4 mo [SD 2.2 mo]). Mean age at walking onset was 19.2, 21.4, and 23.9 months for the HI, LG, and C groups respectively. At walking onset the HI group was significantly younger than the C group (p=0.011). At the gait follow-up that was conducted between 1 and 3 months after walking onset, three groups significantly different in overall gait patterns (p=0.037) were examined by six basic gait parameters including average velocity, stride length, step width, stride time, stance time, and dynamic base. Post-hoc analyses demonstrated that stride length was the gait parameter largely contributing to this overall group difference (p=0.033), and the HI group produced a significantly longer stride length than the C group (p=0.030). In conclusion, the HI treadmill intervention significantly promoted earlier walking onset and elicited more advanced gait patterns (particularly in stride length) in infants with DS.     

Quantitative measures of gait characteristics indicate prevalence of underlying subclinical structural brain abnormalities in high-functioning older adults

Abnormal gait in high-functioning older adults may indicate underlying subtle structural brain abnormalities. We tested the hypothesis that temporal and spatial parameters of gait, including speed, stride length and double support time, are cross-sectionally associated with white matter hyperintensity, subcortical infarcts or brain atrophy on brain MRI. We examined 321 men and women (mean age = 78.3) participating to the Cardiovascular Health Study who were free of dementia or stroke at the time of the gait assessment. Analyses were set with gait as independent variable and brain MRIs as dependent variables. Gait measures were determined from the footfalls recorded on a 4-meter-long instrumented walking surface, the GaitMat II. Brain MRIs were examined for the presence of white matter hyperintensity (WMG, graded from 0 to 9), brain infarcts (predominantly subcortical) and ventricular enlargement (graded from 0 to 9). Slower gait, shorter stride length and longer double support times were associated with greater prevalence of white matter grade > or =3 (p = 0.02), and at least 1 brain infarct (p = 0.04) independent of age. In multivariate logistic regression models adjusted for demographics and clinical cardiovascular diseases, those with gait speed <1.02 m/s were more likely to have WMG > or =3 and at least 1 brain infarct, compared with those with faster gait - odds ratio (OR): 2.85, 95% confidence interval (95% CI): 1.35, 6.02, and OR: 2.09, 95% CI: 1.04, 4.19. Shorter stride length was also associated with greater probability of having at least 1 brain infarct (gait stride <0.88 vs. >1.10 m: OR: 3.20, 95% CI: 1.49, 6.88), while longer double support times were associated with a greater probability of having WMG > or =3 (double support time >0.19 vs. <0.14 s: OR: 2.3, 95% CI: 1.1, 4.7) independent of demographics and clinical cardiovascular diseases. Gait parameters were not significantly associated with ventricular grade. In summary, in this group of high-functioning older adults, poorer gait speed, shorter stride and longer double support time are associated with high white matter disease and subclinical strokes.     

Gait and balance impairment in early multiple sclerosis in the absence of clinical disability

This study evaluated the gait and balance performance of two clinically distinct groups of recently diagnosed and minimally impaired multiple sclerosis (MS) patients (Expanded Disability Status Scale range 0-2.5), compared to control subjects. Ten MS patients with mild pyramidal signs (Pyramidal Functional Systems 1.0), 10 MS patients with no pyramidal signs (Pyramidal Functional Systems 0) and 20 age- and gender-matched control subjects were assessed using laboratory-based gait analysis and clinical balance measures. Both MS groups demonstrated reduced speed and stride length (P < 0.001), and prolonged double limb support (P <0.02), compared to the control group, along with alterations in the timing of ankle muscle activity, and the pattern of ankle motion during walking, which occurred independent of gait speed. The pyramidal MS group walked with reduced speed (P = 0.03) and stride length (P = 0.04), and prolonged double limb support (P =0.01), compared to the non-pyramidal group. Both MS groups demonstrated concomitant balance impairment, performing poorly on the Functional Reach Test compared to the control group (P <0.05). The identification of incipient gait and balance impairment in MS patients with recent disease onset suggests that motor function may begin to deteriorate in the early stages of the disease, even in the absence of clinical signs of pyramidal dysfunction.     

Planned gait termination in cerebellar ataxias

This study set out to characterise the pattern of planned gait termination in a sample of patients with cerebellar diseases. The gait termination phase was recorded, using a motion analysis system, in ten patients with primary degenerative cerebellar disease and in ten controls. The subjects were instructed to walk at different gait speeds and to stop in response to an acoustic signal. Time-distance parameters (step length, step width, double support duration, time-to-slow, stopping time, centre of mass velocity and number of steps) and stability index-related parameters (distance between the "extrapolated centre of mass" (XCoM) and centre of pressure (CoP)) were measured at both matched and self-selected gait speeds. At matched speed the patients, compared with the controls, showed a reduced step length, a greater first and second step width and used more steps to stop. At self-selected speed, almost all the parameters differed from those of the controls. Furthermore, the patients showed an increased stability index, suggesting that they need to maintain a "safety margin" between the XCoM and CoP during the gait termination. Patients develop a series of compensatory strategies in order to preserve balance during planned gait termination, e.g. increasing their step width and number of steps. Ataxic patients need to maintain a safety margin in order to avoid instability when stopping. Given the potential risk of falls when stopping, walking ataxic patients may benefit from a rehabilitation treatment focused on preserving and improving their ability to terminate gait safely.     

Development of independent locomotion in children with a severe visual impairment

Locomotion of children and adults with a visual impairment (ages 1-44, n = 28) was compared to that of age-related individuals with normal vision (n = 60). Participants walked barefoot at preferred speed while their gait was recorded by a Vicon(?) system. Walking speed, heading angle, step frequency, stride length, step width, stance phase duration and double support time were determined. Differences between groups, relationships with age and possible interaction effects were investigated. With increasing age overall improvements in gait parameters are observed. Differences between groups were a slower walking speed, a shorter stride length, a prolonged duration of stance and of double support in the individuals with a visual impairment. These may be considered either as adaptations to balance problems or as strategies to allow to foot to probe the ground.     

Reduced step length,not step length variability is central to gait hypokinesia in people with Parkinson's disease

Objectives

Previous studies found that people with Parkinson's disease (PD) walked at a slower speed and with significantly shorter stride length and/or increase in variability of stride length than control subjects. The present study aimed to examine whether difference existed in amplitude and variability of step length between control and PD subjects if they walked at a similar speed.

Methods

This was a cross-sectional study. Thirteen PD patients and 15 healthy control subjects were instructed to walk at a similar speed on a treadmill under 2 randomized conditions: walking alone (Walk_o) and walking with digit subtraction of 3 (Walk_calculation). Amplitude of step length (cm), variability of step length (%), and percent accuracy of the calculation task (%) were recorded and analysed.

Results

During both Walk_o and Walk_calculation, PD patients had significantly shorter step length and larger step length variability than control subjects (p < 0.05). When a cognitive task was added to walking, PD patients showed a significant decrease in step length without further change in step length variability (p < 0.05).

Conclusion

As reduced step length persisted when the control subjects walked at a speed similar to that of patients, our finding suggests that PD patients had a fundamental problem in regulating the amplitude of step length during walking.