The conventional gait model,an open-source implementation that reproduces the past but prepares for the future

BackgroundThe Conventional Gait Model (CGM), known by a variety of different names, is widely used in clinical gait analysis. We present pyCGM2, an open-source implementation of the CGM with two versions. The first, CGM1.0, is a clone of Vicon Plug In Gait (PiG) with all its variants. CGM1.0 provides a platform to test the effect of modifications to the CGM on data collected and processed retrospectively or to provide backward compatibility.The second version, CGM1.1, offers some practical modifications and includes three well documented improvements.Research questionHow do improvements of the conventional gait model affect joint kinematics and kinetics?MethodThe practical modifications include the possibility to use a medial knee epicondyle marker, during static calibration only, to define the medio-lateral axis of the femur in place of the knee alignment device. The three improvements correspond to the change of pelvis angle decomposition sequence, the adoption of a single tibia coordinate system, and the default decomposition of the joint moments in the joint coordinate system. We validated the outputs of version CGM1.0 against Vicon-PiG, and estimated the effect of the modifications included in version CGM1.1 using gait data collected in 16 healthy participants.ResultsKinematics and kinetics of CGM1.0 were superimposed with that of Vicon-PiG, with root mean square differences less than 0.04° for kinematics and less than 0.05 N.m.kg-1 for kinetics.SignificanceThe differences between the CGM1.1 and CGM1.0 were minimal in the healthy participant cohort but we discussed the expected difference in participants with different gait pathologies.We hope that the pyCGM2 will facilitate the systematic testing and the use of improved processing methods for the conventional gait model.     

Changes in the control of obstacle crossing in middle age become evident as gait task difficulty increases

BackgroundAge-associated physiological changes result in modified gait, such as slower speed, for older adults. Identifying the onset of age-related gait changes will provide insight into the role of aging on locomotor control. It is expected that a more challenging gait task (obstacle crossing) puts more demands on physiological systems, and may reveal gait modifications in a middle-aged group that are not evident in an easier gait task (level walking).Research questionTo identify the effect of advancing age on gait as a function of increasing locomotor challenge during an obstacle crossing task.MethodsThree age groups (young, middle-aged, and older adults) stepped over an obstacle placed in a 15 m walkway. Task challenge ranged from low to high in four conditions: unobstructed gait, 3, 10, and 26 cm obstacles. Gait measures were calculated during the approach and crossing steps.ResultsSignificant interactions were observed for gait speed (age by height by step, p < 0.01), foot placement variability (age by step, p < 0.01) and foot clearance (age by height, p = 0.05). Relative to young adults, older adults walked slower in all conditions and had higher foot clearances for the 10 and 26 cm obstacles. Middle-aged adults walked with speeds and foot clearances that were not different from young adults in the lower gait challenge conditions, and changed to values that were not different from older adults in the highest gait challenge conditions. Foot placement variability was greater for the middle-aged and older groups, but only in the last two steps before the obstacle.SignificanceMultiple gait changes were observed as early as middle-age, and changes in speed and foot clearance became more evident as task difficulty increased. The increased gait challenge placed more demands on the neuromuscular system, revealing age-related gait modifications that were not evident in the level walking gait task.     

Associations of radiographic degeneration and pain with daily cumulative hip loading in patients with secondary hip osteoarthritis

The purpose of this study was to investigate the associations of radiographic and clinical variables of hip osteoarthritis (OA) with alterations in gait and joint loading in patients with secondary hip OA. Fifty females with secondary hip OA were participated. The minimum joint space width (mJSW) of the hip as a degenerative sign and Sharp and center edge (CE) angles as morphological variables were measured radiographically. Hip joint pain was assessed using a visual analog scale. As gait variables, walking speed, range of hip motion, hip moment peak, and hip moment impulse were calculated. Daily cumulative hip loading was calculated as the hip moment impulse multiplied by the mean number of steps per day. After bivariate correlation analyses between dependent (mJSW and pain) and independent variables (age, body mass index, sharp/CE angles, steps per day, and gait variables), separate forward‐backward stepwise multiple regression analyses were performed for each dependent variable. Daily cumulative hip loading in the sagittal plane (β = 0.30, p = 0.021) and age (β = ?0.36, p = 0.007) were significantly associated with the mJSW. Walking speed (β = ?0.36, p = 0.008) and age (β = 0.29, p = 0.031) were significantly associated with hip joint pain. Decrease in daily cumulative hip loading in the sagittal plane was associated with mJSW independently of age. Although the causal relationship was not clear, patients with hip OA reduced total exposure to hip joint loading adaptively rather than lowering the hip moment peak concerning worsening of hip degeneration. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:1977–1983, 2016.

     

社区老年人双重任务行走步态特征与跌倒的关系研究

目的探索社区老年人双重任务行走步态参数与过去一年跌倒史的关系。方法方便抽取135名社区老年人,根据过去一年有无跌倒史分为跌倒组(23名)与未跌倒组(112名)。运用问卷和便携式步态分析仪分别采集老年人一般信息、健康资料与10m双重任务行走步态参数。结果两组居住方式、家庭人均月收入及TUGT比较,差异有统计学意义(均P0.05);两组单脚支撑时间、单脚支撑时间/双脚支撑时间、步幅持续时间、周期时间、地面冲击、落脚强度、离地时脚的角度、速度与步频比较,差异有统计学意义(P0.05,P0.01)。结论双重任务行走时步态性能较差的社区老年人易发生跌倒。政府应加强公共活动场所的安全基础建设,鼓励老年人加强腿部肌肉锻炼和双重任务训练;医务人员应重视对老年患者步态的评估和功能锻炼,提高老年人行走能力,以预防跌倒发生。     

神经节苷脂联合Bobath技术对脑卒中弛缓性瘫痪患者三维步态时空和表面肌电参数的影响

目的：观察神经节苷脂联合 Bobath技术对脑卒中弛缓性瘫痪患者三维步态时空和表面肌电参数的影响。方法将63例脑卒中弛缓性瘫痪患者分为A组31例、B组32例,A组采用Bobath技术、电针和中频治疗,B组在A组治疗基础上加用神经节苷脂治疗。治疗前后检测两组的三维步态时空参数（步速、支撑相、摆动相、双支撑相、步长）和患侧腓肠肌和胫前肌在踝关节屈伸最大等长收缩状态下表面肌电参数[均方根值（RMS）、肌电积分值（iEMG）、协同拮抗率（CR）]。结果治疗前,两组所有参数比较,差异均无统计学意义（P＞0．05）。治疗后两组的步速、支撑相、摆动相、双支撑相、RMS、iEMG、CR和B组的步长均较前改善（P＜0．05）;与A组比较,治疗后B组上述指标的改善更为明显（P＜0．05）。结论在常规治疗基础上,神经节苷脂联合Bobath技术能更好地改善脑卒中弛缓性瘫痪患者三维步态时空和表面肌电各项指标,疗效显著。     

Dynamics of quadrupedal locomotion of monkeys: implications for central control

We characterized the three-dimensional kinematics and dynamics of quadrupedal gait of young adult rhesus and cynomolgus monkeys while they walked with diagonal and lateral gaits at 0.4–1.0 m/s on a treadmill. Rigid bodies on the wrist, ankle, and back were monitored by an optical motion detection system (Optotrak). Kinematic data could be normalized using characteristic stride length, reducing variance due to different gait styles, to emphasize common characteristics of swing and stance parameters among animals. Mean swing phase durations fell as walking speed increased, but the swing phase durations increased at each walking velocity as a linear function of increases in amplitude, thereby following a main sequence relationship. The phase plane trajectories of the swing phases, i.e., plots of the relation of the rising and falling limb velocity to limb position in the sagittal (X–Z) plane, had unique dynamic characteristics. Trajectories were separable at each walking velocity and increases in swing amplitude were linearly related to peak swing velocities, thus comprising main sequences. We infer that the swing phase dynamics are set by central neural mechanisms at the onset of the swing phases according to the intended amplitude, which in turn is based on the walking velocity in the stance phases. From the many dynamic similarities between swing phases and rapid eye movements, we further suggest that the swing phases may be generated by neural mechanisms similar to those that produce saccades and quick phases of nystagmus from a signal related to sensed or desired walking velocity. Grants: This work was supported by National Institute of Health Grants EY11812, EY04148, DC05204, and EY01867.     

社区主观认知下降老年人的运动认知风险综合征发生情况及影响因素研究

背景 运动认知风险综合征（MCR）及主观认知下降（SCD）均为老年人认知下降的早期阶段,MCR目前被认为是一种新型的痴呆前期有效预测综合征,早期对SCD老年人群进行MCR筛查,确定其影响因素,对减少老年人群痴呆及相关不良健康事件的发生具有重要意义。 目的 了解社区SCD老年人的MCR发生情况,并分析其影响因素。 方法 从2019年1月至2022年1月于北京某社区开展的长期队列研究中选取SCD老年人（≥60岁）459例为研究对象。SCD的评估联合使用了简版老年抑郁量表（GDS-15）中有关记忆的问题和蒙特利尔认知评估基础量表中文版（MoCA-B）。采用6 m步速测定法评估老年人的步速,以同时存在SCD和步速下降者为MCR组,以不存在步速下降者为非MCR组。采用自设问卷收集患者一般资料、生理因素、生活方式指标、心理因素、营养状态、患病情况、用药史等信息。采用多因素Logistic逐步回归分析SCD老年人发生MCR的影响因素。 结果 459例社区SCD老年人中,发生MCR者125例（27.23%）。MCR组和非MCR组老年人的年龄、基础性日常生活活动能力（BADL）、工具性日常生活活动能力（IADL）、每周运动时长、焦虑情况、营养状态、患病情况〔高血压、慢性心力衰竭、心律失常、脑卒中/短暂性脑缺血发作（TIA）、多发腔隙性脑梗死、2型糖尿病、周围血管病、肿瘤、骨关节炎、近2年骨折史、眼部疾病、口腔疾病〕、多重用药史比较,差异有统计学意义（P<0.05）。多因素Logistic逐步回归分析结果显示,年龄〔OR（95%CI）=1.083（1.034,1.134）〕、BADL〔OR（95%CI）=0.952（0.914,0.991）〕、IADL〔OR（95%CI）=0.623（0.486,0.798）〕、每周运动时长〔OR（95%CI）=0.505（0.295,0.864）〕、焦虑情况〔OR（95%CI）=2.442（1.225,4.866）〕、高血压患病情况〔OR（95%CI）=1.948（1.086,3.497）〕、脑卒中/TIA患病情况〔OR（95%CI）=3.154（1.745,5.699）〕是社区SCD老年人发生MCR的影响因素（P<0.05）。 结论 社区SCD老年人MCR发生率较高,社区医护人员对社区SCD老年人进行MCR筛查时应更关注年龄、BADL、IADL、每周运动时长、焦虑情况、高血压、脑卒中/TIA等影响因素,协助控制慢性病并建立健康的生活方式,从而改善患者认知情况。     

计算机辅助步态分析系统在偏瘫患者行走功能康复中的作用

目的观察计算机辅助步态分析系统对偏瘫患者步行能力的影响。方法将i00例伴有行走障碍的脑卒中患者随机分为观察组和对照组各50例。两组康复治疗前后（3个月）均采用计算机辅助步态分析系统评价患者步态并进行常规药物治疗，观察组在计算机辅助步态分析系统的评价指导下进行步行能力训练，对照组则不依据步态分析检查结果进行训练。结果康复治疗3个月后，观察组异常步态具有明显改善，两组比较具有显著性差异（P〈0．05）。结论计算机步态分析系统指导步行训练可有效地矫正或改善偏瘫步态。     

减重步行训练对脑卒中后偏瘫步态康复的影响

目的:观察减重步行训练(BWSTT)对脑卒中患者偏瘫步态的恢复作用。方法:51例脑卒中患者分入实验组(21例)和对照组(30例)。两组均进行常规运动疗法(PT),实验组加BWSTT。共6周,5次／周,1单元／天,30min／单元。训练前后各行1次评价。结果:训练后实验组FAC评分、FMA下肢评分、步速、步长均明显提高(P<0.05),患侧单肢支撑期明显延长,双侧支撑期明显缩短(P<0.01),而对照组仅FMA下肢评分明显提高(P<0.001)。两组间对比,仅FMA下肢评分差异无显著性意义(P>0.05),其余各指标均为实验组改善更明显(P<0.05)。结论:BWSTT可提高偏瘫患者的步行能力、步速、步长,增加患侧单肢支撑期,减少双侧支撑期,改善步态对称性。     

Longitudinal Model of Periprosthetic Joint Infection in the Rat

The majority of periprosthetic joint infections occur shortly after primary joint replacement (<3 months) and require the removal of all implant components for the treatment period (~4 months). A clinically relevant animal model of periprosthetic infection should, therefore, establish an infection with implant components in place. Here, we describe a joint replacement model in the rat with ultrahigh molecular weight polyethylene (UHMWPE) and titanium components inoculated at the time of surgery by methicillin-sensitive Staphylococcus aureus (S. aureus), which is one of the main causative microorganisms of periprosthetic joint infections. We monitored the animals for 4 weeks by measuring gait, weight-bearing symmetry, von Frey testing, and micro-CT as our primary endpoint analyses. We also assessed the infection ex vivo using colony counts on the implant surfaces and histology of the surrounding tissues. The results confirmed the presence of a local infection for 4 weeks with osteolysis, loosening of the implants, and clinical infection indicators such as redness, swelling, and increased temperature. The utility of specific gait analysis parameters, especially temporal symmetry, hindlimb duty factor imbalance, and phase dispersion was identified in this model for assessing the longitudinal progression of the infection, and these metrics correlated with weight-bearing asymmetry. We propose to use this model to study the efficacy of using different local delivery regimens of antimicrobials on addressing periprosthetic joint infections. Statement of clinical significance: We have established a preclinical joint surgery model, in which postoperative recovery can be monitored over a multi-week course by assessing gait, weight-bearing, and allodynia. This model can be used to study the efficacy of different combinations of implant materials and medication regimens. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 38:1101-1112, 2020