At Basalt rehabilitation clinic The Hague, gait analysis is currently mostly observational. No objective measures are used and there is no systematic use of recordings. The aim of this research is to find and verify an accessible instrumented gait analysis method that could be implemented in the current care path at Basalt The Hague. The current instrumented gait analysis systems are marker-based. Recently more research has been done with regard to markerless systems, since markers bring along artefacts like the soft-tissue artefact. Markerless systems work with pose detection through artificial intelligence. A limitation of these pose detection systems, is that it is still in a research phase and did not make its way into the clinics yet. In a comparison of the accuracy of open-source pose estimation methods for measuring gait kinematics, OpenPose has been found most accurate.

For this research a program of requirements is made for implementation of instrumented gait analysis in the clinic at Basalt The Hague. The coordinates of anatomical landmarks obtained with OpenPose are processed to kinematic parameters. Besides, spatiotemporal parameters are looked into. A gait analysis set-up (consisting of tripods and mobile phone cameras) with OpenPose is proposed and tested to verify the accuracy. The OpenPose outcomes are compared with the the Simi motion capture system at Basalt Delft. By determining the Pearson correlation coefficients between OpenPose and Simi motion capture system, the kinematic parameters are verified. The mean standard deviations of the repeated recordings with OpenPose are used to determine the repeatability of OpenPose.

With this research is verified that OpenPose is repeatable and that kinematic parameters of the hip and knee are highly correlated to the standard method of instrumented gait analysis used at Basalt. Therefore can be concluded that OpenPose pose detection seems a promising method for determining kinematic and possibly also spatiotemporal parameters of gait. With follow-up research, especially clinical validation, and further development of the data processing, the first steps can be made towards implementation of accessible instrumented gait analysis in the current care path at Basalt The Hague, and possibly other locations and/or institutions.

Introduction:Timely personalized treatment of functional decline depends on early ambulant identification of persons at risk. Regularity of daily body acceleration, quantified by sample entropy (SampEn), is associated with fall risk and is a potential proxy for functional (biopsychosocial) resilience.
Objective: This cross-sectional study associates SampEn of daily life accelerometry with physical (short physical performance battery, SPPB [0 12]) and cognitive functioning (cognitive impairment test, 6 CIT [0-28]).Method: Data was provided from the HIPCARE cohort of 51 community-dwelling adults [81 (75 – 89)] after femur fracture. The SPPB, CIT, and 7 days accelerometry were recorded at three months follow-up after hip surgery. The mean SampEn for different activities was compared between patients with low (<4), moderate (4-9), and high (>9) SPPB and between low (<8) and high (>7) CIT with a significance of p≤0.05Results: Moderate SPPB scores had more regularity (lower SampEn) in complete daily life acceleration signals and during stair-walking than the high SPPB group. In addition, the cognitive impaired group (i.e., high CIT) had more regularity (lower SampEn) than the healthy group during cycling and sitting activities.Discussion and conclusions: More regular accelerations indicate the development of limited physical performance and deterioration of cognitive functions. The findings advocate that acceleration entropy in daily life activities is a promising proxy for physical and mental (biopsychological) functions. A large-scale longitudinal study is needed to examine the potential added value of daily acceleration for the early detection of biopsychosocial functioning.

Introduction: Pes equinus with increased ankle joint stiffness is a common impairment in stroke and Cerebral Palsy (CP) patients with structural and/or neural deficits of the ankle muscles. Equinus gait is characterized by toe-strike, abnormal ankle plantarflexion and decreased ankle range of motion (ROM). A new ankle-foot orthosis (AFO) with negative stiffness was previously developed to compensate for the increased ankle joint stiffness and improve equinus gait, reducing plantarflexion and increasing ankle ROM. The goal of this project was to predict the effects of ankle stiffness compensation on equinus gait simulations.

Methods: Forward simulations of unimpaired and equinus gait were generated in
the sagittal plane with a musculoskeletal model implemented in OpenSim and a
neural controller implemented in SCONE. After validation of the unimpaired gait
simulation, a sensitivity analysis on ankle kinematics was performed, introducing
structural and/or neural alterations of the ankle muscles to achieve an equinus gait. Consecutively, equinus gait simulations were validated with previously collected data of CP patients. Finally, an AFO model was developed in OpenSim to simulate AFO-assisted gait.

Results: The unimpaired gait simulation yielded realistic results, and was robust to all alterations, generating stable gaits. Shorter Gastrocnemius fiber length and/or increased plantarflexor muscles activations, with Tibialis Anterior weakness, had the largest effect on the ankle joint kinematics and resulted in realistic CP equinus gaits. Simulations of AFO-assisted gait resulted in reduced abnormal plantarflexion, and increased ankle ROM in the condition with shorter Gastrocnemius.

Discussion and Conclusion: This study presented realistic simulations of equinus
gait, by modelling structural and/or neural alterations of the ankle muscles and
predicted improved ankle function when compensating ankle stiffness with an external force. Although higher stiffness compensation and more simulations should be obtained, this study provides a solid ground for further investigation of the AFO effects. These results can ultimately assist in the prescription and tuning of the new AFO for patients with equinus.