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     

Role of hypokinesia and bradykinesia in gait disturbances in Huntington's disease

Objective To evaluate specific patterns of locomotion in Huntington's disease (HD) and notably the respective roles of hypokinesia (i. e. a decrease in the amplitude of movement) and bradykinesia (i. e. difficulty in executing a movement, slowness) in gait disturbance. Methods Kinematic, spatial (stride length, speed), temporal (cadence, speed, and stride time) and angular gait parameters (joint ankle range) were recorded in 15 early–stage HD patients by means of a video motion analysis system and then compared with 15 controls and 15 Parkinson's disease (PD) patients. Hypokinesia was studied in terms of both spatial (decrease in stride length) and angular gait parameters (decrease in joint ankle range), whereas hyperkinesia was characterized by an increase in joint ankle range. Bradykinesia (defined by a decrease in gait velocity) was also assessed in terms of temporal parameters (cadence, stride time). We studied the influence of clinical symptoms (motor dysfunction, chorea, overall disability and cognitive impairment) and the CAG repeat number on gait abnormalities. Results we observed a clear decrease in gait speed, a decrease in cadence and an increase in stride time (i. e. bradykinesia) for HD, with significant intra–individual variability. Cadence remained normal in PD. In HD, there was no evidence for a clear decrease in stride length, although the latter is a characteristic feature of hypokinetic gait (such as that observed in PD). Angle analysis revealed the coexistence of hyperkinesia and hypokinesia in HD, which thus participate in gait abnormalities. Gait speed in HD was correlated to the motor part of the UHDRS. Conclusion Gait in HD is mainly characterized by a timing disorder: bradykinesia was present, with severe intra–individual variability in temporal gait parameters.     

Three-dimensional motion analysis of the effects of auditory cueing on gait pattern in patients with Parkinson’s disease: a preliminary investigation

Auditory cueing enhances gait in parkinsonian patients. Our aim was to evaluate its effects on spatiotemporal (stride length, stride time, cadence, gait speed, single and double support duration) kinematic (range of amplitude of the hip, knee and ankle joint angles registered in the sagittal plane) and kinetic (maximal values of the hip and ankle joint power) gait parameters using three-dimensional motion analysis. Eight parkinsonian patients performed 12 walking tests: 3 repetitions of 4 conditions (normal walking, 90, 100, and 110% of the mean cadence at preferred pace cued walking). Subjects were asked to uniform their cadence to the cueing rhythm. In the presence of auditory cues stride length, cadence, gait speed and ratio single/double support duration increased. Range of motion of the ankle joint decreased and the maximal values within the pull-off phase of the hip joint power increased. Thus, auditory cues could improve gait modifying motor strategy in parkinsonian patients.     

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

The purpose of this study was to determine if combining visual and auditory cues has a greater effect on the gait pattern of patients with Parkinson's disease (PD) than the cues applied individually. Twenty-four individuals with idiopathic PD were recruited. Patients, while off antiparkinsonian medications, were measured on a 7.62-m walkway during two trials for each of four conditions performed in random order: without cues, with a visual cue, with an auditory cue and with both cues simultaneously. The auditory cue consisted of a metronome beat 25% faster than the subject's fastest gait speed. Brightly colored parallel lines placed along the walkway at intervals equal to 40% of a subject's height served as the visual cue. Average gait speed, cadence and stride length were calculated for each condition. Gait velocity, cadence and stride length significantly improved (p<005) when cues were used. Visual and auditory cues improved gait performance in patients with PD, but they did so in different ways. Auditory cueing significantly improved cadence, but visual cueing improved stride length. The simultaneous use of auditory and visual cues did not improve gait significantly more than each cue alone.     

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.     

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.     

Gait variability in community dwelling adults with Alzheimer disease

Studies have shown that measures of gait variability are associated with falling in older adults. However, few studies have measured gait variability in people with Alzheimer disease, despite the high incidence of falls in Alzheimer disease. The purpose of this study was to compare gait variability of community-dwelling older adults with Alzheimer disease and control subjects at various walking speeds. Ten subjects with mild-moderate Alzheimer disease and ten matched control subjects underwent gait analysis using an electronic walkway. Participants were required to walk at self-selected slow, preferred, and fast speeds. Stride length and step width variability were determined using the coefficient of variation. Results showed that stride length variability was significantly greater in the Alzheimer disease group compared with the control group at all speeds. In both groups, increases in walking speed were significantly correlated with decreases in stride length variability. Step width variability was significantly reduced in the Alzheimer disease group compared with the control group at slow speed only. In conclusion, there is an increase in stride length variability in Alzheimer disease at all walking speeds that may contribute to the increased incidence of falls in Alzheimer disease.     

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.     

Velocity modulation and rhythmic synchronization of gait in Huntington's disease.

This study analyzed the ability of patients with Huntington's disease (HD) to modulate gait velocity without external sensory cues and in response to an auditory rhythmic cue within a frequency entrainment design. Uncued gait patterns of 27 patients were first assessed during normal, slower, and faster self-paced walking. During rhythmic trials, metronome and musical beat patterns were delivered at rates 10% slower and 10-20% faster than baseline cadence to cue gait patterns. After the rhythmic trials, patients were retested at normal gait speed without rhythm. Gait velocities in the patients with HD were below normal reference values in all ranges. Patients were able to significantly (p <0.05) modulate their gait velocity during self-paced and rhythmic metronome cueing but not during music. The ability to modulate gait velocity was retained regardless of the severity of the disease. Gait velocity declined with an increase in disability and chorea score. The disability score differentiated better between gait velocity of moderately and severe patients than chorea score. Slowness of gait was significantly correlated only with disability score and not with chorea. Patients had more difficulty producing adequate step rates than stride lengths during normal and fast walking speeds. After the rhythmic trials, unpaced gait velocity remained significantly (p <0.05) higher than baseline. This carry-over effect was not seen after the uncued trials. Synchronization ability was deficient in all patients, deteriorated with severity of disease, and was already compromised in patients with soft disease signs. Rhythmic tracking of music declined more with severity of disease than metronome tracking. In summary, patients were able to modulate velocity with and without external cues. Velocity adaptations to the external rhythm in music and metronome were achieved without exact synchronization between step cadence and rhythmic stimulus.     

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...     

Externally provoked freezing of gait in open runways in advanced Parkinson’s disease results from motor and mental collapse

Freezing of gait (FOG) in Parkinson’s disease (PD) is defined as a sudden inability to maintain effective stepping movements. However, its pathophysiology remains unclear. The objectives are: (1) To assess the contribution of both spatial (walking speed, stride length) and temporal parameters (cadence, stride time) and their coefficients of variation to the genesis of FOG in PD. (2) To evaluate whether and how externally imposed modifications of self-determined gait would elicit FOG. We included ten patients with advanced PD, and with daily off drug FOG episodes. We focused on walking in an open runway. For each subject, we manipulated gait by externally imposing four changes in walking speed and four changes in cadence. FOG episodes, often with a long duration of more than 5-s, were observed mostly under conditions with a high imposed cadence. The steps that immediately preceded these episodes were mainly characterized by an increase in cadence and an increase in stride length variability. The results also underscore that FOG can be elicited in a laboratory setting when patients are placed under considerable strain, at least in advanced stages of PD. Patients were unable to adequately negotiate the extreme imposed cadence condition, and this resulted in frequent FOG episodes, even while walking in an open runway. Placing advanced PD patients into extreme imposed conditions leads to a motor wise and mental collapse response, culminating in FOG. Future work should establish the relevance of these findings for the more common forms of FOG, including brief episodes during turning or gait initiation.     

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.     

Three-dimensional gait biomechanics in Parkinson's disease: evidence for a centrally mediated amplitude regulation disorder.

We examined whether people with Parkinson's disease (PD) have a central amplitude regulation disorder using three-dimensional (3-D) gait analyses to compare the effects of medication and attentional strategies on gait in 12 PD subjects and 12 matched comparison subjects. Subjects with PD first performed several 10-m gait trials at preferred speed while off levodopa. They then walked at preferred speed on levodopa; off levodopa with cues; and on levodopa with cues. Control subjects walked at preferred speed and then with visual cues to match their stride length to PD values. As well as spatiotemporal footstep data, pelvic and lower limb kinematic profiles and angle-angle diagrams were produced for sagittal, coronal, and transverse plane movements using a 3-D motion analysis system. In people with PD, decreased step length was accompanied by reduced movement amplitude across all lower limb joints, in all movement planes. When control subjects were required to walk with short steps matched to the size of PD comparisons, they displayed a similar multijoint reduction in amplitude. For PD subjects, both levodopa and visual cues increased movement amplitude across all lower limb joints. Amplitude increased further when levodopa and visual cues were combined, resulting in normalization of step length. This finding suggested that reduced step length is due to a mismatch between cortically selected movement amplitude and basal ganglia maintenance mechanisms. Levodopa and cues normalized amplitude across all joints by altering motor set and bypassing defective basal ganglia mechanisms.     

The effect of rhythmic somatosensory cueing on gait in patients with Parkinson's disease

BACKGROUND AND AIMS: Gait and gait related activities in patients with Parkinson's disease (PD) can be improved with rhythmic auditory cueing (e.g. a metronome). In the context of a large European study, a portable prototype cueing device was developed to provide an alternative for rhythmic auditory cueing: rhythmic somatosensory cueing (RSC, a miniature vibrating cylinder attached to the wrist). We investigated whether PD patients could adapt their walking pattern using RSC under conditions of changing walking speed and the presence of potentially distracting visual flow while walking on a treadmill. METHODS: A total of 17 patients with PD participated (mean age 63.4+/-10.3 years; Hoehn-Yahr score 2.5+/-0.9, mean Unified Parkinson's Disease Rating Scale score 49.8+/-13.7, mean disease duration 7.7+/-5.1 years). They performed systematic walking speed manipulations under 4 conditions in a random order: (1) no cue, no visual flow, (2) no cue, visual flow, (3) cue, no visual flow and (4) cue, visual flow. Visual flow in the form of a virtual corridor that moved at the current walking speed was projected on a 2 x 2 m rear-projection screen. The cueing rhythm was set at -10% of preferred stride frequency at each speed. Stride frequency was assessed using peaks in the trajectories of thigh sagittal plane segmental angles. RESULTS: Walking with RSC resulted in lower stride frequencies, and thus larger step lengths (p-values <0.05), regardless of walking speed. The presence of visual flow did not impair the use of RSC, as evidenced by the lack of differences between conditions 3 and 4 (p>0.05). CONCLUSION: Rhythmic somatosensory cueing may be a viable alternative for auditory cueing and is robust to changes in walking speed and visual distractors.     

The attentional cost of external rhythmical cues and their impact on gait in Parkinson’s disease: effect of cue modality and task complexity

Summary Changes in gait performance in 153 subjects with PD using three rhythmical cues (auditory, visual and somatosensory) were measured during a simple walking task and a dual walking task in the home. Subjects were ‘on’ medication and were cued at preferred step frequency. Accelerometers recorded gait and walking speed, step amplitude and step frequency were determined from raw data. Data were analysed with SAS using linear regression models. Gait performance during a single task reduced with cues in contrast to a dual task where PD subjects appeared to benefit from rhythmical cues (increased speed and step length). Effects were dependent on cue modality with significant improvements for auditory cues compared to others. A significant short-term carry-over effect of cues reduced 3 weeks later. Cues may reduce attentional demands by facilitating attentional allocation, accounting for differences of cue seen during single and dual task. Furthermore cue modality may influence attentional demand which is an important consideration for rehabilitation.     

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。     

Listening to humans walking together activates the social brain circuitry

Human footsteps carry a vast amount of social information, which is often unconsciously noted. Using functional magnetic resonance imaging, we analyzed brain networks activated by footstep sounds of one or two persons walking. Listening to two persons walking together activated brain areas previously associated with affective states and social interaction, such as the subcallosal gyrus bilaterally, the right temporal pole, and the right amygdala. These areas seem to be involved in the analysis of persons' identity and complex social stimuli on the basis of auditory cues. Single footsteps activated only the biological motion area in the posterior STS region. Thus, hearing two persons walking together involved a more widespread brain network than did hearing footsteps from a single person.     

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.     

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。     

Unintentional modulations of human gait by optical flow

Visual whole-field motion is known to trigger motor responses which minimize retinal slip (VOR, OKN and control of balance). In locomotion, however, the retinal slip is utilized to control the velocity and direction of displacement. The present experiment was aimed at determining how the velocity of optical flow affects the regulation of locomotion. Unintentional modulations in velocity, stride length and cadence were analyzed using a task in which artificial optical flow gave the subjects the impression they were walking at a different speed than they actually were. Slight but systematic modifications in locomotion were observed: experimental variation of the optical flow resulted in a decrease in stride length. None of the subjects were aware of this decrease, despite the fact that their muscular and articular afferences provided them with supraliminal information. Although visual flow velocity is usually a direct consequence of walking velocity, experimental modifications of visual flow were found here to cause unintentional modulations in locomotor parameters (stride length and cadence) more than in their product (velocity).