Spatiotemporal gait parameters for older adults – An interactive model adjusting reference data for gender,age, and body height

IntroductionSince it is well documented that spatiotemporal gait parameters are affected by body size, it is of limited clinical value to compare individual scores against reference values without taking body size into consideration. For older adults, reference values have been presented in recent reports, but unfortunately the effect of body size on gait characteristics was not taken into account and neither prediction intervals nor percentile ranks were included. It is the aim of this study to present and assess a model where individual spatiotemporal gait parameter values for older adults can be compared to reference values adjusted for gender, age, and body height.MethodsReference gait data were collected from l464 older adults aged 69–80 years with no impairments believed to affect gait, stratified by gender, intermediately adjusted to a common body height using a pendulum model and entered into a simple regression model for each parameter with age as predictor. From the regression coefficients predicted gait parameter values could be back transformed to the individual body height of a new subject. Calculations were done using spreadsheet formulae and equations.ResultsA spreadsheet based graphical user interface (GUI) has been developed in Microsoft Excel® where individual spatiotemporal gait data is entered for comparison with reference data taking gender, age and body height into account, and returning predicted point estimates with confidence intervals, prediction intervals, and percentile ranks.SignificanceA GUI solution where individual spatiotemporal gait data is compared to reference data is feasible to researchers and for clinical use. To the best of our knowledge, this is the first model presented for comparison of basic gait parameters between individuals and reference data from older adults where gender, age, and body height are taken into account.     

Laboratory-Based Gait Variability and Habitual Gait Entropy Do Not Differentiate Community-Dwelling Older Adults from Those with Subjective Memory Complaints

BackgroundAge-related cognitive decline may be delayed with appropriate interventions if those at high risk can be identified prior to clinical symptoms arising. Gait variability assessment has emerged as a promising candidate prognostic indicator, however, it remains unclear how sensitive gait variability is to early changes in cognitive abilities.Research questionDo community-dwelling adults over 65 years of age with subjective memory complaints differ from those with no subjective memory concerns in terms of laboratory-measured or free-living gait variability?MethodsThis cross-sectional study recruited 24 (age = 73.5(SD 6.4) years) community-dwelling people with subjective memory complaints and twenty seven (age = 70.9(4.3) years) individuals with no subjective memory concerns. A sample of 9 individuals with diagnosed mild dementia were also assessed (age = 86.5(7.0) years). Gait variability was assessed in a laboratory during walking at preferred pace (single-task) and while counting backward by seven (dual-task). Sixteen passes over a 4.88 m walkway in each condition were recorded and step length and duration variability was analysed. Free-living gait was assessed with a waist-worn accelerometer by identifying gait bouts of at least one min duration, and the mean multiscale sample entropy in one mins non-overlapping epochs is reported. Statistical inferences were based on analysis of variance using sex and group as the factors.ResultsNo difference between those with subjective memory complaints and those without were observed in either laboratory- or free-living gait variability estimates. Both laboratory- and free-living gait variability were higher in those with mild dementia compared to the other groups.SignificanceAssuming that subjective memory complaints are on the pathway from cognitively intact to cognitively frail, the findings raise the hypothesis that subjective memory complaints occur earlier in the pathophysiology than measurable changes in laboratory or free living gait. Alternatively the gait variability assessments utilised may have been too insensitive.     

Altered trunk movements during gait in children with spastic diplegia: Compensatory or underlying trunk control deficit?

Altered trunk movements during gait in children with CP are considered compensatory due to lower limb impairments, although scientific evidence for this assumption has not yet been provided. This study aimed to study the functional relation between trunk and lower limb movement deficits during gait in children with spastic diplegia. Therefore, the relationship between trunk control in sitting, and trunk and lower limb movements during gait was explored in 20 children with spastic diplegia (age 9.2 ± 3 yrs; GMFCS level I n = 10, level II n = 10). Trunk control in sitting was assessed with the Trunk Control Measurement Scale (TCMS), a clinical measure that reflects the presence of an underlying trunk control deficit. Trunk movements during gait were measured with a recently developed trunk model including the pelvis, thorax, head, shoulder line and spine. Lower limb movements were assessed with the Plug-in-Gait model (Vicon®). Range of motion (ROM) of the different trunk segments was calculated, as well as the Trunk Profile Score (TPS) and Trunk Variable Scores (TVSs). Similarly, the Gait Profile Score (GPS) and Gait Variable Scores (GVSs) were calculated to describe altered lower limb movements during gait. Correlation analyses were performed between the presence of impaired trunk control in sitting (TCMS) and altered trunk movements during gait (ROM, TPS/TVSs) and between these altered trunk movements and lower limb movements (GPS/GVSs) during gait. A poorer performance on the TCMS correlated with increased ROM and TPS/TVSs, particularly for the thorax, indicating the presence of an underlying trunk control deficit. No significant correlation was found between the TPS and GPS, suggesting that overall trunk and lower limb movement deficits were not strongly associated. Only few correlations between specific lower limb deficits (GVSs for hip ab/adduction, knee flexion/extension and ankle flexion/extension) and TVSs for thorax lateral bending and rotation were found. This study provided first evidence that the altered trunk movements observed during gait should not be solely considered compensatory due to lower limb impairments, but that these may also partially reflect an underlying trunk control deficit. A better understanding of underlying trunk control deficits in children with CP may facilitate targeted therapy planning and ultimately can optimize a child's functionality.     

Attention modulates step initiation postural adjustments in Parkinson freezers

BackgroundIn view of freezing of gait's circumstances of occurrence in Parkinson's disease, attentional resources appear to be involved in step initiation failure. Anticipatory postural adjustments (APAs) are essential because they allow unloading of the stepping leg and so create the conditions required for progression.Our main objective was to establish whether or not a change in attentional load during step initiation modulates APAs differently in patients with vs. without freezing of gait.MethodsThree groups of 15 subjects were recruited: elderly people and parkinsonian patients with or without freezing of gait. Attention was modulated before step execution by means of an auditory oddball discrimination task with event-related potential recording. The primary endpoint was the occurrence of inappropriate APAs following the attentional task, i.e. APAs not followed by a step after an intercurrent auditory stimulus.ResultsIn parkinsonian patients with freezing of gait, inappropriate APAs were recorded in 63% of the trials and were observed more frequently than in patients without freezing of gait (51%) and elderly controls (48%). Furthermore, inappropriate APAs in freezers were longer and more ample than in parkinsonian non-freezers and controls. Lastly, postural preparation was impaired in the parkinsonian patients.ConclusionOur results indicate that allocation of attentional resources during step preparation influences the release of APAs differently in freezers and non-freezers. Modulating attentional load is partly responsible for triggering an inappropriate motor program. This difficulty in focusing attention or resisting interference may contribute (at least in part) to the gait initiation failure observed in parkinsonian freezers.     

Early phenotypic differences between Parkinson's disease patients with and without freezing of gait

BackgroundPrevious studies have associated freezing of gait in Parkinson's disease with the presence of specific phenotypic features such as mood disturbances, REM sleep behavior disorder and selective cognitive impairments. However, it is not clear whether these features are present in the earlier stages of disease or simply represent a more general pattern of progression. To investigate this issue, the current study evaluated motor, cognitive, affective and autonomic features as well as REM sleep behavior disorder in Parkinson's disease patients in the early stages of the condition.MethodsThirty-eight freezers and fifty-three non-freezers with disease duration of less than five years and a Hoehn and Yahr stage of less than three were included in this study. The groups were matched on a number of key disease features including age, disease duration, motor severity and dopamine dose equivalence. Furthermore, patients were assessed on measures of motor, cognitive, affective and autonomic features, as well as REM sleep behavior disorder.ResultsCompared to non-freezers, patients with freezing of gait had significantly more non-tremor symptoms and a selective impairment on executive functions, such as set-shifting ability and working memory. Freezers and non-freezers did not differ on measures of tremor, autonomic function, REM sleep behavior disorder, mood or more general cognition.ConclusionThese results suggest the pathophysiological mechanisms underlying freezing of gait in the early clinical stages of Parkinson's disease are likely to be related to specific changes in the frontostriatal pathways rather than being due to brainstem or more diffuse neuropathology.     

单侧全膝置换前后女性患者步态特征分析

目的研究单侧全膝置换(total knee arthroplasty,TKA)手术前后女性患者双侧下肢步态特征。方法基于三维步态采集和独立样本t检验,对比10例女性患者单侧TKA手术前后双侧下肢的步态参数,并分别与对照组10例健康志愿者比较,分析女性患者双侧步态差异及分别与正常步态的差异。结果术前患者非手术侧支撑期、膝关节内收角度峰值、冠状面活动度和屈曲力矩峰值显著大于手术侧(P0.05),术后无统计学差异;与对照组比较,术前患者步速、步长较小,双支撑期较长,手术侧膝关节伸展和内收角度峰值、冠状面活动度、屈曲和外展力矩峰值较小,内收力矩峰值较大,非手术侧膝关节伸展角度峰值较小,屈曲和内收力矩峰值较大,均存在统计学差异(P0.05),术后双侧膝关节伸展角度和内收力矩峰值与对照组的显著差异持续存在(P0.05)。结论单侧TKA能减轻患者疼痛,改善双侧下肢步态偏差,但与对照步态仍存在差异。患者肌力及本体感受等关节功能尚未恢复,病理步态与不良体态仍然存在,应加强患侧肌力锻炼及步态矫正训练。女性患者术后同时应注意步速控制,以防膝关节受力增加。     

A diagnostic ceiling for exome sequencing in cerebellar ataxia and related neurological disorders

Genetic ataxias are associated with mutations in hundreds of genes with high phenotypic overlap complicating the clinical diagnosis. Whole‐exome sequencing (WES) has increased the overall diagnostic rate considerably. However, the upper limit of this method remains ill‐defined, hindering efforts to address the remaining diagnostic gap. To further assess the role of rare coding variation in ataxic disorders, we reanalyzed our previously published exome cohort of 76 predominantly adult and sporadic‐onset patients, expanded the total number of cases to 260, and introduced analyses for copy number variation and repeat expansion in a representative subset. For new cases (n = 184), our resulting clinically relevant detection rate remained stable at 47% with 24% classified as pathogenic. Reanalysis of the previously sequenced 76 patients modestly improved the pathogenic rate by 7%. For the combined cohort (n = 260), the total observed clinical detection rate was 52% with 25% classified as pathogenic. Published studies of similar neurological phenotypes report comparable rates. This consistency across multiple cohorts suggests that, despite continued technical and analytical advancements, an approximately 50% diagnostic rate marks a relative ceiling for current WES‐based methods and a more comprehensive genome‐wide assessment is needed to identify the missing causative genetic etiologies for cerebellar ataxia and related neurodegenerative diseases.     

步态周期下半月板损伤对膝关节生物力学性能的影响

文题释义：半月板撕裂：膝关节内半月型纤维软骨破裂,撕裂原因主要是由于膝半屈或全屈位下的扭转力所造成。半月板分为内侧半月板和外侧半月板,内侧半月板较大且固定,外侧半月板较小,实验主要研究外侧半月板撕裂对力学机制的影响。 动态有限元分析：将人体正常完整步态周期作为边界条件施加在膝关节半月板模型中,观察在完整步态周期下半月板以及胫骨软骨的应力变化趋势及所受应力值大小。 背景：目前国内外对膝关节半月板的生物力学分析十分广泛,但大多集中于对膝关节屈曲运动状态下的研究,针对完整步态周期下膝关节半月板生物力学的有限元分析还不完善。 目的：通过对比外侧半月板撕裂模型与健康半月板模型,了解完整步态周期下半月板损伤后的生物力学变化机制。 方法：以健康成年人膝关节CT扫描数据为基础,建立包括胫-股骨、半月板、关节软骨在内的健康膝关节有限元模型,并在健康模型基础上进一步构建膝关节外侧半月板撕裂模型,探究在完整步态周期下膝关节外侧半月板撕裂的生物力学机制,并与健康膝模型进行对比。 结果与结论：①两种模型完整步态周期内的胫骨软骨瞬时应力变化趋势一致,但半月板撕裂模型中胫骨软骨在每一个瞬时受到的应力值均大于健康半月板模型,半月板撕裂模型与健康模型中胫骨软骨所受最大应力值分别为30,20.5 MPa;②两种模型完整步态周期内的半月板瞬时应力变化趋势是一致的,但撕裂模型中完整步态周期内半月板受到的应力均大于健康模型,半月板撕裂模型与健康模型中半月板所受最大应力值分别为69.8,41.3 MPa;③在步态周期的前60%,半月板撕裂模型中的胫骨软骨最大应力分布远大于健康模型,且随着步态周期的增长,接触范围逐渐向软骨外部边缘蔓延;在步态周期的60%以后,作用在胫骨软骨上的应力较小,最大应力的分布范围也比较小;④两种模型中健康内侧半月板应力分布基本一致,而撕裂的外侧半月板最大应力分布范围较健康内侧半月板广,在裂纹周围出现了较严重应力集中现象,且随着步态周期的进行,应力集中区域逐渐向裂纹靠近半月板前角处偏移;⑤结果表明半月板是人体膝关节中重要的承重部件,从生物力学角度可以较为直观地观察到半月板损伤对人体膝关节的危害。 ORCID: 0000-0002-2155-0058(吴铮) 中国组织工程研究杂志出版内容重点：人工关节;骨植入物;脊柱;骨折;内固定;数字化骨科;组织工程     

Comparative abilities of Microsoft Kinect and Vicon 3D motion capture for gait analysis

Biomechanical analysis is a powerful tool in the evaluation of movement dysfunction in orthopaedic and neurologic populations. Three-dimensional (3D) motion capture systems are widely used, accurate systems, but are costly and not available in many clinical settings. The Microsoft Kinect? has the potential to be used as an alternative low-cost motion analysis tool. The purpose of this study was to assess concurrent validity of the Kinect? with Brekel Kinect software in comparison to Vicon Nexus during sagittal plane gait kinematics. Twenty healthy adults (nine male, 11 female) were tracked while walking and jogging at three velocities on a treadmill. Concurrent hip and knee peak flexion and extension and stride timing measurements were compared between Vicon and Kinect?. Although Kinect measurements were representative of normal gait, the Kinect? generally under-estimated joint flexion and over-estimated extension. Kinect? and Vicon hip angular displacement correlation was very low and error was large. Kinect? knee measurements were somewhat better than hip, but were not consistent enough for clinical assessment. Correlation between Kinect? and Vicon stride timing was high and error was fairly small. Variability in Kinect? measurements was smallest at the slowest velocity. The Kinect? has basic motion capture capabilities and with some minor adjustments will be an acceptable tool to measure stride timing, but sophisticated advances in software and hardware are necessary to improve Kinect? sensitivity before it can be implemented for clinical use.     

脑白质病变的研究进展

脑白质病变与临床上许多疾病密切相关,而且影响到了有关疾病的预后。本文就近年来脑白质病变的研究进展进行了综述,希望能为今后的研究提供新的思路。