Research Wim Saeys

Abstract

Over the years, Belgium has experienced a significant surge in cycling, driven by active policies implemented across various levels of government, from local to federal, and spurred by the impact of the COVID-19 crisis1. The proportion of bicycle users has risen from 8% in 2010 to 12% in recent years. Notably, Flanders leads in cycling popularity at 18%, followed by Brussels at 4%, and Wallonia at 2%, with the Brussels region experiencing a near doubling of cyclists since the onset of the pandemic1. Additionally, the use of speed pedelecs, particularly prevalent in Flanders with around 12,000 registered in 2019, reflects a broader trend, as Belgium saw a total of 53,000 speed pedelecs registered nationally by the beginning of 2022. The Bicycles market in in Belgium is expected to grow by 2.99% (2024-2028) resulting in a market volume of US$1.62bn (1.49 billion euro) in 20282. In this perspective, Belgian professional cyclists occupy a prominent position worldwide and contribute significantly to the country's identity and cycling culture. In this context, this 4D4BIKE project is initiated, focused on the development of biomechanical algorithms for assessing cyclists by using the unique 4D full body scanner. This recently installed scanner provides a markerless 4D (3D over time) human full body shape consisting of a watertight mesh with a density of more than 50,000 points. It incorporates texture with sub-1mm accuracy at 178 3D images per second, obtaining dynamic biometric measurements (such as height and waist circumference) in one second. The 4D4BIKE project integrates advanced 4D scanning by developing algorithms to gain valuable new insights into various aspects of cycling biomechanics, including joint angles, muscle activation patterns and overall body kinetics. Parameters such as balance control and movement asymmetry can also be assessed as a function of metadata (e.g., shape, age and gender) benefiting cyclists, coaches and sports scientists. The integration of 4D scanning with advanced biomechanical algorithms represents an advanced approach to provide a comprehensive personalized assessment of the cyclist and bike to optimize bike fit, improve aerodynamics and ultimately improve overall performance and comfort on the bike. Before the 4D4BIKE services can be offered to industry a number of bottlenecks still need to be addressed: 1) Biomechanical and ergonomic analysis of 4D dynamic body metrics by developing specific algorithms for processing scripts and formats to visualise and analyse cyclists' performance; 2) Validation of the developed algorithms protocols, products, and devices to meet the specific industry and costumer demand.

Researcher(s)

• Promoter: Truijen Steven
• Co-promoter: Saeys Wim

Research team(s)

• Movement Antwerp (MOVANT)

Project type(s)

• Research Project

Abstract

Rationale: Cerebrovascular Accident (CVA) is one of the main causes of morbidity and disability worldwide. A frequent consequence of stroke is spasticity in the affected limbs. Spasticity is a velocity-dependent increase in muscle reflex activity that affects both resting muscle tone (hypertonicity) and voluntary movements. Lower limb spasticity is associated with limitations in walking ability, resulting in an increased incidence of falls, a reduced quality of life and greater caregiver burden. Two treatments for post-stroke spasticity are injection of botulinum neurotoxin (BTX A) and dry needling (DN) to chemically or mechanically disrupt signal transmission at the neuromuscular junction in the affected muscle respectively. Both treatments reduce spasticity and improve functional walking. As BTX A injection has some adverse effects, DN may be an effective, minimally-invasive, non-pharmacological alternative to the more invasive chemical denervation. However, while some local (muscle) mechanisms of action of BTX A and DN have been described, there is little information about their actions at the central (spinal) level, on activity, quality of life and cost-effectiveness. Objectives: The primary objective is to determine the mechanisms of action of BTX A infiltration and DN on lower limb post-stroke spasticity at the central (spinal) level. The secondary objectives are to determine safety and feasibility of each treatment and their effects at muscle and functional levels, quality of life and cost-effectiveness. The primary hypothesis is that DN treatment will be comparable to BTX A and will decrease post-stroke spasticity by decreasing stretch reflex excitability at the central (spinal) level. Improving knowledge of the mechanisms of action of both interventions will lead to more informed treatment prescription and better clinical mobility outcomes for post-stroke patients. Methods: This prospective study will compare BTX A and DN treatment on spasticity relief in people who have sustained a first stroke 3-12 months previously and who have plantar flexor spasticity. Ninety patients will be recruited from 3 centers (30 per site) in Spain, Belgium and Canada. We will use a multiple-baseline time-series design across pairs of subjects matched for age and time since stroke. BTX A will be injected once and DN will be applied once weekly for 12 weeks. Effects will be evaluated before, during and after treatment and at a 4 week follow-up by blinded evaluators. Effects on spasticity will be evaluated at the central (spinal) level using a physiological measure of motoneuronal excitability (Tonic Stretch Reflex Threshold and its velocity sensitivity) and at the muscle level by quantifying morphological changes with ultrasound imaging and the perceived resistance to stretch (Mod-Mod Ashworth Scale). We will also assess effects on gait (Timed Up and Go, 10 Meter Walk Test and instrumented gait analysis) and quality of life (EuroQOL-5D). Cost-effectiveness of each intervention will be determined. A patient Advisory Group will be created to engage patients by asking for feedback during the study and to contribute to results dissemination. Outcomes: Although BTX is the gold standard for post-stroke spasticity treatment, DN treatment has shown to be effective with potentially fewer adverse effects. However, DN has not yet been routinely implemented in clinical practice and there are no comparative studies with BTX A and mechanisms of action remain unknown. This impedes prescription of the best available treatment to post-stroke patients considering spasticity pathophysiology. Results of this feasibility study (proof of concept) will determine the mechanisms of action of both treatments so that future studies with larger samples and other neuropathologies can be developed.

Researcher(s)

• Promoter: Saeys Wim
• Co-promoter: Truijen Steven

Research team(s)

• Movement Antwerp (MOVANT)

Project website

Project type(s)

• Research Project

Abstract

Stroke incidence is increasing and, consequently, so are the number of motor impaired survivors. Whereas patient tailored rehabilitation strategies are believed to greatly improve recovery, a reliable biomarker for gait outcome prediction that enables such patient tailored rehabilitation is currently missing. Therefore, this project aims to explore whether brain structural connectivity between areas responsible for gait can be used as a biomarker for gait recovery prediction. This will be done by characterizing brain connectivity during the first 6 months after stroke using diffusion magnetic resonance imaging (dMRI) and correlating these findings with gait recovery as measured by a comprehensive gait analysis. Brain connectivity will be assessed considering 12 brain areas and 18 white matter pathways between them. Gait analysis will include data on kinetics, kinematics and muscle activity. All results will be used for a machine learning protocol composed by network-based statistics and deep learning As such, when a correlation can be established, the dMRI assessment of connectivity could serve as a biomarker to guide rehabilitation strategies, early in the course of recovery, so that rehabilitation outcome can be improved.

Researcher(s)

• Promoter: Yperzeele Laetitia
• Co-promoter: Saeys Wim
• Fellow: Van Hinsberg Amber

Research team(s)

• Translational Neurosciences (TNW)

Project type(s)

• Research Project

Abstract

Society 5.0 is a vision in which emerging technologies are used as a tool in health. In Medicine 4.0 smart health is required for innovation. In this context, the multidisciplinary interfaculty institute CHaT, Center for Health and Technology, has already more than ten years of experience in methods and algorithms developed using optoelectronic marker-based measurement systems for biomechanical movement and gait analyses. The main drawback of this optical technology is the use of passive markers because it is time-consuming to place the markers on the skeleton of the subject. In addition, occlusions are common since each marker must be detectable by at least 2 cameras at any time in order to be correctly interpolated. Recently, CHaT successfully installed a unique 4D4A lab that consists of a markerless 4D (3D plus time) body scanner. It provides a 3D human full body shape that consists of a watertight mesh with a density of 50,000 points, adding time as a 4th dimension. It includes texture with a sub-1mm accuracy at 178 3D images per second, obtaining more than 100 dynamic biometric measurements (like height and waist circumference) in a second. This offers additional opportunities, such as measuring during COVID time and a free natural movement of the test subject. Parameters such as center of mass, balance control, gait spatiotemporal parameters and movement asymmetry can be assessed in the 4D4A lab also as a function of metadata (e.g., shape, age and gender). Established research results can be redefined, such as mechanical energy estimation approaches on the center of mass and the sum of segmental energies during sports and regular physical activities such as walking and cycling. The 4D scanner provides new scientific insight into movement patterns correlated to different types of body forms and somatotype classification in terms of 4D data. Possible restrictions in the movement of body parts against each other can be assessed in the 4D4A lab, e.g., restriction of range of motion, gait in people with neurological conditions, amputees and obese people. Overall, the 4D4A lab is a solution to improve the efficiency and sustainability of the health care system increasing the effectiveness of the therapy and empowerment of the patients. Before the CHaT service platform is self-sufficient, by providing 4D4A lab services to industry, hospitals and research institutions, a number of bottlenecks still need to be addressed: 1) Validation of the developed algorithms, protocols, products and devices to meet specific customer's demand; 2) Development of a business plan to establish a CHaT service platform to convert 4D high-tech knowledge into a service platform.

Researcher(s)

• Promoter: Truijen Steven
• Co-promoter: Saeys Wim

Research team(s)

• Movement Antwerp (MOVANT)

Project website

Project type(s)

• Research Project

Abstract

Society 5.0 is a vision in which emerging technologies are used as a tool in health. In Medicine 4.0 smart health is required for innovation. The multidisciplinary interfaculty institute CHaT (Center for Health and Technology), has already more than ten years of experience in methods and algorithms developed using optoelectronic marker-based measurement systems for biomechanical movement and gait analyses. The main drawback of this optical technology is the use of passive markers because it is time-consuming to place the markers on the skeleton of the subject. In addition, occlusions are common since each marker must be detectable by at least 2 cameras at any time in order to be correctly interpolated. To solve this, a new 4D4A scan lab (4D scanner for Accelerating Advanced Motion Analysis and Application), that is unique in the world was recently installed in CHaT with the goal of opening new frontiers in Medicine 4.0, elevating the University of Antwerp to one of the top universities in the world for Human Modelling and Simulation in Medicine. The 4D4A scan lab offers the possibility to capture the human body in 4D (3D + time) without the use of markers so that close contact is no longer required. This offers some opportunities such as measuring in COVID time and a free natural movement of the test person due to the absence of annoying sticked markers. With an accuracy of less than 1 mm, 178 3D images are recorded per second and processed automatically. In addition, the 4D4A scan lab can extend sparse skeletal movements and static 3D geometric information into accurate new dynamic 4D body measurements such as an arm or abdominal circumference over time. This now opens new applications, not only in basic or clinical research, for example monitoring gait and balance in stroke patients, but also in many industrial sectors, such as biomedical engineering and industrial ergonomics. Before the 4D4A scan lab can be offered as a service to industry, hospitals and research institutions, a number of bottlenecks still need to be addressed: 1) The initialisation in the 4D4A scan lab: preparation, coordination and general management of the 4D4A Lab activities; 2) Simultaneous 4D motion tracking and reconstruction of 4D digital modelling of the human shape, complex geometry, and soft tissue synchronizing different devices; 3) Biomechanical and ergonomic analysis of 4D dynamic body metrics by developing specific algorithms for processing scripts and formats to visualise and analyse with free software packages e.g., Blender (blender.org) and OpenSim (simtk.org/projects/opensim); 4) Validation of the developed algorithms protocols, products, and devices to meet the specific demand from the industry; 5) Development of a business plan for future creation of a service platform for CHaT (Center of Health and Technology) in order to transform 4D high-tech knowledge into a service platform, creating new collaborations resulting in services, patents and spin-offs.

Researcher(s)

• Promoter: Truijen Steven
• Co-promoter: Saeys Wim

Research team(s)

• Movement Antwerp (MOVANT)

Project website

Project type(s)

• Research Project

Abstract

The object of the services (hereinafter referred to as the "Services") is to provide research assets related to the area of Human Digital Twin and Human Digital Modelling, making use in particular of the 4D4A Lab of the ChaT Institute of Antwerp and complementing research work initiated by LIST's HUMOD research group. More precisely, it consists in building an experimental framework exploiting the 4D scanning lab to build Digital Twins of People in their environment (HDT). For all the scenario proposed, the experiments will concern anthropometrics measurement and the observation of behaviours that are deviating from an ideal reference. Each time, there would be a HDT created and a Digital Twin (DT) of the environment or/and of the other entity with whom the human is interacting. When observations and analyses are made, an HDT+DT formal model is updated with the findings, maintaining the synchronization between the physical entities and their digital model, to prepare for future works where the DT would be exploited for simulations and integrated in Virtual Reality environments.

Researcher(s)

• Promoter: Truijen Steven
• Co-promoter: Saeys Wim

Research team(s)

• Movement Antwerp (MOVANT)

Project type(s)

• Research Project

Abstract

After stroke, people can experience several impairments. Besides sensorimotor impairments, stroke often have to deal with cognitive disorders including disorientation in time and space, decreased information processing time and volume, memory problems and attentional deficits. One of these post-stroke attentional deficits is visuospatial neglect (VSN) characterized by impaired awareness for visual stimuli located on the contralesional side of space. People with VSN experience significant postural impairments and a high fall risk. In addition, consequences can be more practical of nature as patients with attentional deficits are, for example, unaware of the traffic lights at street crossings or even traffic in general, but also lack the ability to find products at grocery stores. It is obvious that people dealing with cognitive impairments encounter difficulties in all aspects of ADL (Activities of Daily Living) and community participation, and even lack the ability to live independently at home. Unfortunately, there is to date no adequate way of assessing VSN after neurological impairments with good clinimetric properties such as high ecological validity, reliability and discriminating ability between different modalities of VSN. As a consequence, treatment options are sparse and especially focused on compensatory recovery. Moreover, with current standard pen-and-paper tasks, it is hard to quantify eye-movements in relation to head movements relevant for the interpretation of the performance of the patient whether or not the patient uses compensations. Moreover, patients cannot train independent at home with assessment and monitoring on remote (telerehabilitation). As a result, patients remain highly dependent of the spontaneous recovery of the neural system because of the small treatment effects currently seen in clinical practice. However, a huge amount of patients will have persistent VSN after rehabilitation leading to substantial loss of community participation with a high dependency on (in)formal care. This project aims to deliver a solution for the aforementioned problems by means of a virtual reality (VR) application. VR has the potential to provide a three-dimensional real-life environment increasing ecological validity of the assessment of neglect. The recent technical developments in consumer head mounted displays have made virtual reality a mature, reliable and affordable technology. This means for this application that patients will not only rely on equipment accessible at hospitals or rehabilitation centers, but they can even undergo treatment at home and at their own convenience, making telerehabilitation possible. The primary users are professional caregivers within the field of neurological rehabilitation such as neuropsychologists, physiotherapists and occupational therapists. Some patients, who can take responsibility for their own rehabilitation, can use the application independently within the care facility or at home (telerehabilitation).

Researcher(s)

• Promoter: Saeys Wim
• Co-promoter: Truijen Steven

Research team(s)

• Movement Antwerp (MOVANT)

Project type(s)

• Research Project

Abstract

The human body is a complex bio-mechanical system that exhibits many variations in geometry and movements. Advancements in 3D scanning and 3D modeling allow to construct precise and high-resolution models of the human body. Such a 3D model often contains more than 2GB of information such that recording, processing, transmission and data storage is labor and time intensive. In this project we acquire a 3D body scanner that captures the human body shape in high precision and with virtually no effort. The equipment will allow to register the human body with an accuracy of 1mm and up, at a frame rate of 10 3D scans per second. This so called 4D scanner (3D + time) constitutes the core of our 4D center of expertise, in which the research groups Product Development, MOVANT, Vision Lab, EVECO and Op3Mech together with Center for Health and Technology (CHaT) have joined forces in a complementary collaboration with the aim to use dynamical models of the human body for the development of new products with improved comfort and functionality, to design fundamentally new products with important applications in health care, and to improve our understanding of the evolutionary history of the human body. The combination of academic and industrial expertise of Kinesiology with Product Development and virtual modeling and simulations makes the center unique in the world. The consortium will tackle open design problems with applications for mass customization (3D printing) and wearables.

Researcher(s)

• Promoter: Truijen Steven
• Co-promoter: Ribbens Bart
• Co-promoter: Saeys Wim
• Co-promoter: Sijbers Jan
• Co-promoter: Van Dongen Stefan
• Co-promoter: Verwulgen Stijn

Research team(s)

• Movement Antwerp (MOVANT)

Project type(s)

• Research Project

Abstract

Visuospatial neglect (VSN) is a frequent post-stroke neuropsychological cognitive disorder which leaves patients with impaired or even lost awareness for stimuli and/or events on the contralesional hemispace. VSN is reported to occur in 30-70% of right-brain strokes and 20-60% of left-brain strokes. Although spontaneous neurological recovery of VSN occurs in most patients within the first 10-12 weeks post-stroke, 20-40% of patients with VSN still show symptoms a year-post stroke. The latter might have important consequences, as VSN is negatively associated with the motor recovery of the upper limb and independence during activities of daily living (ADL). Although recovery of gait is a primary goal within stroke rehabilitation, little is known about the impact of VSN on the true motor recovery of the lower limbs and on motor performance in general (as measured by gait, balance control and truncal function). As this impact is still unknown, it is difficult for clinicians to provide accurate rehabilitation strategies. Therefore, it is important to unravel the interaction between VSN on one hand and motor recovery and motor performance on the other hand. This will give us more insights in the interplay between spatially-oriented cognitive processes and motor functioning, therefore providing a possible framework for the development of new innovative rehabilitation strategies. The presence of an interaction between cognition (e.g. VSN) and motor function raises the question whether training one aspect can have carry-over effects to the other. A very relevant question is thus whether spatial retraining, designed to enhance VSN, can indirectly stimulate the recovery of motor function and performance as well. In this four-year project, we will address three main research objectives 1) Investigating the impact of VSN on true motor recovery of the lower limbs 2) Investigating the impact of VSN on motor performance as measured by gait, balance control, truncal function 3) Investigating the carry-over effects of spatial retraining on true motor recovery of the lower limbs and motor performance

Researcher(s)

• Promoter: Saeys Wim
• Fellow: Embrechts Elissa

Research team(s)

• Movement Antwerp (MOVANT)

Project type(s)

• Research Project

Abstract

Visuospatial neglect (VSN) is a neuropsychological cognitive condition characterized by an attention deficit to one side of the hemispace, often provoked by stroke. Patients with VSN fail to pay attention to the contralesional hemispace. Approximately 25-30% of stroke patients are confronted with VSN of which 40% still show VSN a year post-stroke. Patients with VSN need more time to recover from sensory-motor impairments, do not reach the same level of motor performance, and experience limitations in activities of daily living (ADL) as compared to post-stroke patients without VSN. However, until present it still remains unclear how VSN contributes to the poorer functional outcomes as observed in post-stroke patients. Results from studies investigating the role of VSN in motor deficits are inconsistent. Some studies show that patients with VSN have worse balance control and gait abilities as compared to patients without VSN, whereas others reject these findings. However, an important limitation of these studies is that they do not take into account the different subtypes of VSN. The different subtypes of VSN are based on the range of space in which the patients experience VSN, namely the personal (own body), peri-personal (within reach) and extra-personal space. It has been shown that these subtypes are important, as balance control and ADL improvement can differ within patients with VSN, depending on which subtype of VSN is most dominantly present. However, since research on this topic is only beginning to emerge, in-depth knowledge regarding the influence of the type of VSN on motor function is lacking. More specifically, the contribution of the different subtypes of VSN on balance control, gait, truncal function and perception of visual verticality has not yet been investigated, especially not from a biomechanical point of view. By unravelling this contribution, the mechanisms of action of VSN will become clearer. This will lead to a better understanding of the interactions between cognitive and motor impairments seen in post-stroke patients with VSN. Therefore, these insights might in turn fundamentally improve the way that the rehabilitation of post-stroke patients with VSN is currently provided. For example, to date, (spatial) cognitive and motor interventions are separately administered, and these cognitive therapies are not yet used to stimulate the motor system. Before cognitive therapies designed to enhance VSN can be recommended to stimulate motor improvements, a clear understanding and consensus regarding the influence of the subtypes of VSN on balance control, gait, truncal function and estimation of visual verticality is necessary. Within this pilot project, we aim to gain insight into the specific contribution of VSN on balance control, gait, truncal function and estimation of visual verticality, especially considering the subtypes of VSN using a biomechanical and clinical approach. Therefore, this project will deepen the understanding of the poor functional outcome that often accompanies post-stroke patients with VSN. The following research questions are considered within the current project: (I.) Do post-stroke patients with VSN have altered balance control, gait, truncal function and estimation of visual verticality compared to post-stroke patients without VSN, as measured by a combination of assessment methods? (II.) Is this dependent on the subtype of VSN? This funding will be used as seed money by providing the foundation for a novel research project which will be submitted to FWO in 2020, in which we aim to investigate the carry-over effects of VSN training on motor performance in post-stroke patients with VSN.

Researcher(s)

• Promoter: Gebruers Nick
• Co-promoter: Saeys Wim

Research team(s)

• Movement Antwerp (MOVANT)

Project type(s)

• Research Project

Abstract

Animal models suggest a limited time window of increased repair activity in the brain during the first weeks after damage, for example after a stroke. Within this time window, responsiveness to therapy is increased suggesting that this is the optimal time to start intensive rehabilitation. In great contrast, early rehabilitation is experienced by stroke patients as a time of being physical inactive. This lack of rehabilitation might explain rather disappointing mobility outcome, since a great amount of stroke survivors struggle to achieve independent community ambulation. The World Health Organisation expects an increase to 1.5 million new cases of stroke per year in 2025. If innovation in rehabilitation cannot be provided, the increasing incidence of stroke will inevitably lead to a growing chronic stroke population and a great burden for our society. A novel therapeutic strategy is a wearable exoskeleton. This device allows an earlier initiation of more intensive rehabilitation as it assists patients in walking even if they are severely affected. This technology has the potential to change acute stroke rehabilitation from an inactive into a motivating, active time as it allows early training of meaningful activity. However, due to its recent development this type of therapy is not yet investigated. We aim to fill this gap with the proposed project by investigating the effectiveness of this approach and provide evidence on an optimal time window for rehabilitation.

Researcher(s)

• Promoter: Truijen Steven
• Co-promoter: Saeys Wim
• Co-promoter: Yperzeele Laetitia
• Fellow: Schröder Jonas

Research team(s)

• Movement Antwerp (MOVANT)

Project website

Project type(s)

• Research Project

Abstract

Animal models have shown that motor training is effective only if initiated early after stroke. This activity-induced recovery pattern temporally matches increased gene expression important for neuronal growth and plasticity in the post-stroke brain. It seems that the brain after damage induces a window of enhanced neuroplasticity during which greatest rehabilitation gains can be achieved. In human stroke care, earlier rehabilitation is associated with improved outcome, however it remains unknown whether a similar time window exists and how to take advantage in clinical practice. In the current research project, gait training will be initiated at a very early stage using a mobile, wearable exoskeleton allowing even acute patients to walk over-ground. A comparison of clinical outcome with a group receiving the same intervention at a later stage will allow to investigate on the factor timing. Moreover, an association between functional improvement and outcomes on neuro-motor recovery (neuro-imaging, Fugl-Meyer Assessment, biomechanical gait analysis) will be investigated. This will enlighten our understanding on when an intervention should be provided in order to affect the proportions of plastic re-organization. Further research on larger populations with a longer follow-up is needed to confirm preliminary results and finally implement these insights into therapeutic strategies and clinical practice. This approach can lead to substantial changes in how rehabilitative treatment is provided to neurological patients.

Researcher(s)

• Promoter: Truijen Steven
• Co-promoter: Saeys Wim

Research team(s)

• Movement Antwerp (MOVANT)

Project type(s)

• Research Project

Abstract

Animal models suggest a limited time window of increased repair activity in the brain during the first weeks after damage, for example after a stroke. Within this time window, training responsiveness is increased suggesting that this is the optimal time to start intensive rehabilitation, e.g. gait training. Disappointingly, early stroke care is characterized by physical inactivity. This lack of intensive therapy probably explains rather disappointing mobility outcome, since half of stroke survivors leave rehabilitation facilities in a wheelchair. The World Health Organisation expects 1.5 million new cases of stroke per year in 2025. If innovation in stroke rehabilitation lacks, the increasing burden of stroke will inevitably lead to a growing disabled and dependent chronic stroke population. A novel therapeutic strategy are wearable exoskeletons. This device allows an earlier and more intensive rehabilitation approach as it assists in weightbearing and walking. This technology has the potential to change acute stroke rehabilitation from a passive into a motivating, active time as it allows early training in an enriched learning environment. However, due to its recent development this type of therapy is not yet investigated. We aim to fill this gap with the proposed project by delivering published evidence on feasibility and effectiveness.

Researcher(s)

• Promoter: Truijen Steven
• Co-promoter: Parizel Paul
• Co-promoter: Saeys Wim
• Fellow: Schröder Jonas

Research team(s)

• Movement Antwerp (MOVANT)

Project type(s)

• Research Project

Abstract

The objective of this PhD study is to investigate dynamic balance control in a population consisting of healthy adults, patients with vestibular dysfunction and stroke patients, thereby exploring different strategies to adapt gait to reduced dynamic balance control. To do so, biomechanical measures of gait stability, will be considered as primary outcome measures. Secondary outcome measures are postural instability, falls and fear of falling, documented using the "Dizziness Handicap Inventory" (DHI) and the "Activities specific Balance Confidence scale" (ABC). Fall risk is determined using standardized clinical tests. The goal of this study is to gain further insight into the relation between variability in foot placement, measures of biomechanical stability and postural instability, risk of falling and documented falls. Different populations will be considered, consisting of community dwelling adults, patients with vestibular deficit and stroke patients. Patients with vestibular deficit are an interesting population to study gait adaptability because, despite loss of vestibular function, in unilateral vestibular deficit no increased risk of falling is observed. In stroke patients, on the other hand, up to 50 percent annually reports a fall. Differences in gait adaptability strategies in these three populations will be investigated using a case-control design. To investigate predictive ability of gait stability measures a prospective cohort study will be performed. Insight into gait adaptability strategies creates opportunities to develop guidelines for gait training and rehabilitation.

Researcher(s)

• Promoter: Hallemans Ann
• Co-promoter: Saeys Wim
• Fellow: Herssens Nolan

Research team(s)

• Movement Antwerp (MOVANT)

Project type(s)

• Research Project

Abstract

The skin is the largest organ of the human body. It is a barrier between our body and the environment protecting us from dehydration, infection and injuries. The skin thus provides us with a sense of touch which has several functions such as 1) providing tactile information about our environment and 2) providing input to enable motor interactions with our direct environment e.g. grasping and manipulating objects. Due to the bimodal functionality of the tactile sense, the skin is particularly interesting for communicating motion related instructions through haptic cues directly engaging our motor learning systems. Opportunities for applications have been identified in sports and training, surgery, music, navigation, prosthesis, to develop assistive devices e.g. navigation aid for the visually impaired and for balance correction in vestibular disorders, to attain correct posture, gait, and for the purpose of rehabilitation e.g. after stroke. However, research is mainly confined to in-lab applications. In order to unlock the realm of opportunities for off-site applications, wearable haptic communication systems for posture and movement management should be developed and evaluated. Thereby vibrotactile signals directly deployed onto the skin are identified most promising for wearable systems. Frequency, intensity/amplitude, burst, and rhythm characteristics for optimal perception at various body locations are known in literature. We will investigate the accuracy of a basic system that steers actual posture and movement towards a reference condition through feedforward, that is, the subject receiving instructions on the actual or future desired reference condition. The independent variable in our study design is the feedforward time. The depended variable is a measure accuracy obtained by integrating the total immediate joint angle differences of desired and reference position over the time domain. An optimal feedforward time is explored and validated for movement instructions and for obstacle avoidance with vision and in blindfolded subjects.

Researcher(s)

• Promoter: Verwulgen Stijn
• Co-promoter: Saeys Wim
• Co-promoter: Truijen Steven

Research team(s)

• Product development

Project type(s)

• Research Project

Abstract

In-depth biomechanical gait analyses have contributed to the understanding of movement patterns. However, movement analysis in home situations or even outdoors will augment its benefits. In this project we will develop a model linking 7 Xsens motion trackers to study trunk performance and locomotion. Furthermore, the reliability and validity of this model will be investigated by comparing the Xsens model with a Vicon optical camera system.

Researcher(s)

• Promoter: Truijen Steven
• Co-promoter: Saeys Wim
• Co-promoter: Vereeck Luc

Research team(s)

• Movement Antwerp (MOVANT)

Project type(s)

• Research Project