The analysis of human walking gait is a complex skill for physical therapy students to learn. As a result, students are at risk for a cognitive overload when confronted with these materials. Cognitive load consists of both intrinsic and extraneous loads as well as the germane processes that are required by the learners to process the information in working memory. As working memory is limited in its capacity to process new information, it is necessary to manage the cognitive load experienced by the learners. Intrinsic cognitive load is related to the complexity of the materials that must be learned and cannot be altered by instructional design without sacrificing initial understanding. An isolated elements instructional format purports to reduce the intrinsic CL experienced by learners by isolating the content into the individual elements prior to introducing any complex relationships that may exist between the elements. The purpose of this study was to examine the cognitive load and learning outcome effects of an isolated elements instructional format versus an interacting elements format when teaching observational gait analysis to physical therapy students. A total of 72 students enrolled in a Doctor of Physical Therapy program participated in this study. Mixed factorial designs assessed both between-group and within-group outcomes. The independent variables were the group assignments (isolated or interacting) and time. The dependent variables were cognitive load and learning outcomes. Cognitive load was measured with 7-point Likert-type scales for both mental effort and task difficulty at five separate time points. Learning outcomes were assessed through performance scores and confidence ratings on a posttest and a 1-week follow-up test. Animated videos were used as the medium for instructional delivery. In the isolated elements group, the learners received the content in several separate videos that isolated each of the sub-phases of gait prior to viewing a summary video that included all of the interacting gait cycle components. Learners in the interacting elements group received the content in one video that included the full gait cycle followed by the same summary video. Students in the isolated elements groups reported lower mental effort ratings immediately after viewing the isolated elements videos than did the interacting group after viewing the single video tutorial. However, there was no differences in either mental effort or task difficulty ratings at the other time points during the lesson or during the assessments. Performance scores and confidence ratings did not differ between the two groups. Within-group analyses found that there were significant changes over time in both groups for mental effort, performance scores, and confidence ratings. A statistically significant change was noted over time for task difficulty in the interacting elements group. The reduction in mental effort ratings immediately following the tutorial content for the isolated elements group lends support the theory that isolating the individual elements prior to teaching the complex interactions can reduce cognitive load for learners. However, this reduction in cognitive load did not translate into improved test scores or confidence compared to the interacting elements group. Future research is needed to identify instructional methods that can further reduce the cognitive load and increase the learning outcomes of students learning observational gait analysis. In addition, alternative objective methods of assessing cognitive load should be explored.

Introduction: The prefrontal cortex (PFC) is highly susceptible to age-related deterioration. As such, executive function deficits are commonly observed when older adults process two attention-demanding tasks simultaneously. Everyday tasks such as walking and talking on the phone involve executive functions and the integration of cognitive-motor pathways. However, less is known about this relationship as cognitive demands increase. Methods: Twenty healthy older adults (M = 71.8 years, SD = 6.4) performed four auditory cognitive tasks of increasing demand, including a simple reaction time (SRT), go/no-go (GNG), n-back (NBK), and double number sequence (DNS) task with or without self-paced walking (i.e., single- versus dual-task). Using a blocked design, prefrontal hemodynamic changes (i.e., oxy- [∆HbO2] and deoxyhemoglobin [∆HbR]) were measured using functional near-infrared spectroscopy (fNIRS) and performance was assessed using measures of response time (s), accuracy (% correct) and gait speed (m/s). Results: Prefrontal activation decreased between the single- and dual-tasks across all task demands. Behaviourally, the SRT response times were significantly faster than GNG and NBK. Accuracy decreased between single- and dual-tasks and with increasing demand, but the NBK and DNS tasks were not significantly different. An interaction between task and demand was observed for gait speed such that the DNS dual-task was significantly slower than the single-task. Conclusion: Neural findings support an automatic locomotor control strategy in that cerebral oxygenation decreased between single- and dual-tasks and gait speed was maintained up until the most demanding cognitive task. However, decreased prefrontal activation was inefficient at supporting response time and accuracy performance which may indicate that cognitive performance is differentially affected by cognitive demand and deficits in executive functioning.

ACL (anterior cruciate ligament) injuries of the knee joint alter biomechanics and may cause abnormal loading conditions that place patients at a higher risk of developing osteoarthritis (OA). There are multiple types of ACL reconstruction (ACLR), but all types aim to restore anterior tibial translation and internal tibial rotation following surgery. Analyzing knee joint contact loads provide insight into the loading conditions following ACLR that may contribute to the long-term development of OA. Ten ACLR subjects, who underwent the same reconstruction, performed gait and cycling experiments while kinematic and kinetic data were collected. Inverse dynamic analyses were performed on processed data using OpenSim to calculate reconstructed and contralateral knee joint contact loads which were then compared between gait and cycling at both moderate and high resistances. Significant differences were found between gait and cycling at either resistance for tibiofemoral (TF) compressive, anterior shear, lateral shear forces, and internal abduction and internal rotation moments for both ACLR and contralateral knees. Anterior shear force was largest for cycling at a high resistance, however, since the ACL provides a posterior restoring force and is more engaged at low flexion angles, adjusting for flexion angles when measuring AP shear forces should be considered. Overall, the calculated loading conditions suggest cycling provided better joint stability by limiting anterior tibial translation and internal tibial rotation compared to gait. The results suggest cycling is a better rehabilitation exercise to promote graft healing and limit abnormal loading conditions that increase the risk of developing OA.

This diploma thesis deals with design and implementation of the controllers of a mobile walking robot. The advantage of these controllers are their kinematics and geometrics independent representation, which allow to use them for different robot types and tasks. In this thesis the contact controller is designed, which minimizes residual forces and torques at the robot's center of gravity, and thereby stabilize robot's body. Next the thesis deals with a posture controller, which maximizes a heuristic posture measure to optimize posture of robot body. Because of this optimization, legs are moved away from their limits and therefore they have more working space for next move. Implementation of the chosen solution is made on the robot's MATLAB mathematical model. Controllers are composed into a control basis, that allows to solve general control tasks by simultaneous combination of contained controllers. The algorithm was created for that simultaneous activation and its operation was explained on flow charts.

Walking is the most common form of human locomotion and the systematic study thereof is known as gait analysis. Measurement and assessment thereof have application in many fields including clinical diagnosis, rehabilitation and biomechanics. The process of gait evaluation is typically done using an optical motion analysis system combined with stationary force platforms. This is considered the gold standard, but unfortunately, has several drawbacks. It is expensive, requires dedicated laboratories with spatial restrictions, calls for lengthy set up and post-processing times and cannot be used in 'real-world' environments. Alternative systems based on wearable sensors have been developed to overcome these limitations. The Council for Scientific and Industrial Research (CSIR) has therefore developed a prototype wearable sensor unit consisting of an inertial measurement unit (IMU). The objective of the current study is, therefore, to advance the prototype to a wearable multi-sensor system for quantitative gait analysis. The focus is on the development of the pre- and post-processing algorithms and methods used to transform the measurements into interpretable information. The focus outlined includes establishing techniques for synchronising the data from the sensors offline, pre-processing the signals, developing algorithms for stride and gait event detection, selecting an appropriate gait model and defining methods for estimating gait parameters. The determined parameters were the spatio-temporal and joint kinematics (hip, knee and ankle). The algorithms and new system were validated against the Vicon motion capture system through gait analyses. The twenty able-bodied volunteers that took part were required to walk across the laboratory six times at three self-selected walking speeds (slow, normal and fast). For the sake of simplicity and due to various limitations, only data in the sagittal plane of the right lower limb of each volunteer was used to validate the wearable system and associated algorithms. The results obtained were then evaluated against several validation criteria. The absolute mean difference between the estimated timing of detected gait events of the two systems was consistently small (between 0.021 and 7.25% of the gait cycle overall). The spatially dependent parameters, stride length and walking speed, had significant maximum mean absolute percentage errors (31.9 and 34.5% respectively), but with little variation. Excluding outliers, that of the temporal parameters, stride time and cadence, was significantly lower (5.7 and 5.6% respectively). The kinematic results were substantially comparable with a minimum correlation co-efficient of 0.86 and a maximum RMSE of 7.8 degrees with little variation implying repeatability. Although there were some discrepancies between the outputs, the wearable sensor system and its corresponding algorithms were considered feasible and potentially beneficial to developing countries like South Africa. Recommendations for future work include synchronising data between the wearable and reference system for stride-to-stride comparisons and validating algorithms using a known reliable wearable system. / Dissertation (MEng)--University of Pretoria, 2017. / Mechanical and Aeronautical Engineering / MEng / Unrestricted

Objective: To perform kinematic and kinetic analyses on the static standing and ambulation in subjects after stroke with and without wearing a 5-degree lateral-wedged insole. Design: Ten hemiparetic individuals with unilateral stroke were recruited. Participants performed quiet stance and ambulation with no insole wedge, paretic side wedged, and nonparetic side wedged in a random order. The vertical ground reaction force and temporal-spatial parameters of gait were measured. Symmetry index was also calculated. Results: During quiet stance, the symmetry index of weight bearing improved significantly with nonparetic side-wedged (P < 0.017), but not with paretic side-wedged insoles. During ambulation, the symmetry indices of kinematic and kinetic measurements in the frontal plane were not significantly different among the three conditions. However, the contralateral knee abductor moment was significantly (P < 0.05) less than that of the nonparetic limb during nonparetic side-wedged ambulation. The ipsilateral hip and knee abductor moments were significantly (P < 0.05) less than the nonparetic limb during paretic side-wedged ambulation. Conclusions: Application of nonparetic side wedge insole can improve stance symmetry and tends to reduce the paretic knee abductor load during ambulation. The effects of paretic side-wedged insole are different. The present results provide guidelines for the placement of wedges in the shoes of individuals after stroke.

The biomechanics of slips are commonly studied in laboratory settings in an effort to improve the understanding of slip mechanisms for the advancement of slip and fall prevention strategies and risk assessment methods.  Prior studies have shown changes in gait after slipping, and these changes can reduce the external validity of experimental results.  As such, most researchers only slip participants one time.  The ability to slip participants more than once, after allowing gait to return to a natural baseline, would improve the experimental efficiency of these studies.  Therefore, the goal of this study was to determine the time duration of slip-induced changes in gait. The required coefficient of friction (RCOF), a parameter highly predictive of risk of slipping, was measured on thirty-one young male adults during level gait on three separate days before slipping, immediately (<10 minutes) after slipping, and either one, two, four, or six weeks later.  On average, the RCOF decreased 12% from its baseline value (0.20) after slipping, indicating the adoption of a protective gait with a decreased risk of slipping.  The RCOF data trended toward baseline values 4-6 weeks after the slip experience, but remained statistically different from baseline.  This indicates that the slip-induced gait alterations have long-lasting effects, enduring up to six weeks after the slip experience. / Master of Science

Fall accidents are one of the most serious problems leading to unintentional injuries and fatalities among older adults. However, it is difficult to assess individuals' fall risk and to determine who are at risk of falls and in need of fall interventions. Therefore, this study was motivated by a need to provide a cogent fall risk assessment strategy that may be conducive to various wireless platforms. It aimed at developing a fall risk assessment method for evaluating individuals' fall risk by providing diagnostic modalities associated with gait. In this study, a "determinants of gait" model was adopted to analyze gait characteristics and associate them with fall risk. As a proof of concept, this study concentrated on slip-induced falls and the slip initiation risks. Two important parameters of determinants of gait, i.e. the pelvic rotation and the knee flexion, were found to be associated with slip initiation severity. This relationship appeared to be capable of differentiating fallers and non-fallers within older adults, as well as differentiating normal walking conditions and constrained walking conditions. Furthermore, this study also leveraged portable wireless sensor techniques and investigated if miniature inertial measurement units could effectively measure the important parameters of determinants of gait, and therefore assess slip and fall risk. Results in this study suggested that pelvic rotation and knee flexion measured by the inertial measurement units can be used as a substitution of the traditional motion capture system and can assess slip and fall risk with fairly good accuracy. As a summary, findings of this study filled the knowledge gap about how critical gait characteristics can influence slip and fall risk, and demonstrated a new solution to assess slip and fall risk with low cost and high efficiency. / Ph. D.

The medial ganglionic eminence (MGE) is a progenitor domain in the subpallium that produces both locally-projecting interneurons which undergo tangential migration in structures such as the cortex as well as long-range projection neurons that occupy subcortical nuclei. Very little is known about the transcriptional mechanisms specifying the migratory behavior and axonal projection patterns of these two broad classes of MGE-derived neurons. In this study, I identify St18 as a novel transcriptional determinant specifying projection neuron fate in the MGE lineage. St18 is transiently expressed in the MGE subventricular zone (SVZ) and mantle, and I assessed its function using an ES cell-based model of MGE development. Induction of St18 is sufficient to direct ES-derived MGE neurons to adopt a projection neuron-like identity as defined by migration and morphology. Through gene expression analysis I identified a downstream effector of St18, Cbx7, which is a component of Polycomb repressor complex 1. I find that Cbx7 is essential for projection neuron-like migration and is not involved in St18-mediated projection neuron-like morphology. Using genetic loss-of-function in mice, I find that St18 is required for the production of globus pallidus pars externa (GPe) prototypic projection neurons. Single cell RNA sequencing revealed that St18 regulates MGE output of specific neuronal populations: in the absence of St18, I observe a large expansion of cortical interneurons at the expense of putative GPe neurons. I also find that, following St18 genetic loss of function, mouse walk cycles are disrupted downstream of a loss of a critical neuronal projection from the GPe to the sub thalamic nucleus (STN). These results characterize a novel transcriptional determinant that directs GPe prototypic projection neuron identity within the MGE lineage. Further, I have identified a downstream target of St18, Cbx7, which regulates only the migratory behavior of long-range projection neurons, suggesting that specific features of MGE projection neuron identity may be governed in a compartmentalized fashion by distinct transcriptional modules downstream of St18. I’ve also demonstrated the role of the GPe PV+ prototypic neurons in the production and maintenance of mouse locomotor gait.

京都大学 / 0048 / 新制・課程博士 / 博士(人間健康科学) / 甲第19278号 / 人健博第30号 / 新制||人健||3(附属図書館) / 32280 / 京都大学大学院医学研究科人間健康科学系専攻 / (主査)教授 市橋 則明, 教授 三谷 章, 教授 松田 秀一 / 学位規則第4条第1項該当 / Doctor of Human Health Sciences / Kyoto University / DFAM