539 research outputs found
A Review Study for Robotic Exoskeletons Rehabilitation Devices
Nowadays, robotic exoskeletons demonstrated great abilities to replace traditional rehabilitation processes for activating neural abilities performed by physiotherapists. The main aim of this review study is to determine a state-of-the-art robotic exoskeleton that can be used for the rehabilitation of the lower limb of people who have mobile disabilities as a result of stroke and musculoskeletal conditions. The study presented the anatomy of the lower limb and the biomechanics of human gait to explain the mechanism of the limb, which helps in constructing a robotic exoskeleton. A state-of-the-art review of more than 100 articles related to robotic exoskeletons and their constructions, functionality, and rehabilitation capabilities are accurately implemented. Moreover, the study included a review of upper limb rehabilitation that has been studied locally and successfully applied to patients who exhibited significant improvements. Results of recent studies herald an abundant future for robotic exoskeletons used in the rehabilitation of the lower extremity. Significant improvement in the mechanism and design, as well as the quality, were observed. Also, impressive results were obtained from the performance when used by patients. This study concludes that working and improving the robotic devices continuously in accordance with the cases are necessary to be treated with the best results and the lowest cost
TicTacToes: Assessing Toe Movements as an Input Modality
From carrying grocery bags to holding onto handles on the bus, there are a
variety of situations where one or both hands are busy, hindering the vision of
ubiquitous interaction with technology. Voice commands, as a popular hands-free
alternative, struggle with ambient noise and privacy issues. As an alternative
approach, research explored movements of various body parts (e.g., head, arms)
as input modalities, with foot-based techniques proving particularly suitable
for hands-free interaction. Whereas previous research only considered the
movement of the foot as a whole, in this work, we argue that our toes offer
further degrees of freedom that can be leveraged for interaction. To explore
the viability of toe-based interaction, we contribute the results of a
controlled experiment with 18 participants assessing the impact of five factors
on the accuracy, efficiency and user experience of such interfaces. Based on
the findings, we provide design recommendations for future toe-based
interfaces.Comment: To appear in Proceedings of the 2023 CHI Conference on Human Factors
in Computing Systems (CHI 23), April 23-28, 2023, Hamburg, Germany. ACM, New
York, NY, USA, 17 page
Embodied interaction with guitars: instruments, embodied practices and ecologies
In this thesis I investigate the embodied performance preparation practices of guitarists to design and develop tools to support them. To do so, I employ a series of human-centred design methodologies such as design ethnography, participatory design, and soma design. The initial ethnographic study I conducted involved observing guitarists preparing to perform individually and with their bands in their habitual places of practice. I also interviewed these musicians on their preparation activities. Findings of this study allowed me to chart an ecology of tools and resources employed in the process, as well as pinpoint a series of design opportunities for augmenting guitars, namely supporting (1) encumbered interactions, (2) contextual interactions, and (3) connected interactions.
Going forward with the design process I focused on remediating encumbered interactions that emerge during performance preparation with multimedia devices, particularly during instrumental transcription. I then prepared and ran a series of hands-on co-design workshops with guitarists to discuss five media controller prototypes, namely, instrument-mounted controls, pedal-based controls, voice-based controls, gesture-based controls, and “music-based” controls. This study highlighted the value that guitarists give to their guitars and to their existing practice spaces, tools, and resources by critically reflecting on how these interaction modalities would support or disturb their existing embodied preparation practices with the instrument.
In parallel with this study, I had the opportunity to participate in a soma design workshop (and then prepare my own) in which I harnessed my first-person perspective of guitar playing to guide the design process. By exploring a series of embodied ideation and somatic methods, as well as materials and sensors across several points of contact between our bodies and the guitar, we collaboratively ideated a series of design concepts for guitar across both workshops, such as a series of breathing guitars, stretchy straps, and soft pedals. I then continued to develop and refine the Stretchy Strap concept into a guitar strap augmented with electronic textile stretch sensors to harness it as an embodied media controller to remediate encumbered interaction during musical transcription with guitar when using secondary multimedia resources.
The device was subsequently evaluated by guitarists at a home practicing space, providing insights on nuanced aspects of its embodied use, such as how certain media control actions like play and pause are better supported by the bodily gestures enacted with the strap, whilst other actions, like rewinding the play back or setting in and out points for a loop are better supported by existing peripherals like keyboards and mice, as these activities do not necessarily happen in the flow of the embodied practice of musical transcription.
Reflecting on the overall design process, a series of considerations are extracted for designing embodied interactions with guitars, namely, (1) considering the instrument and its potential for augmentation, i.e., considering the shape of the guitar, its material and its cultural identity, (2) considering the embodied practices with the instrument, i.e., the body and the subjective felt experience of the guitarist during their skilled embodied practices with the instrument and how these determine its expert use according to a particular instrumental tradition and/or musical practice, and (3) considering the practice ecology of the guitarist, i.e., the tools, resources, and spaces they use according to their practice
Design and Development of Biofeedback Stick Technology (BfT) to Improve the Quality of Life of Walking Stick Users
Biomedical engineering has seen a rapid growth in recent times, where the aim to facilitate and equip humans with the latest technology has become widespread globally. From high-tech equipment ranging from CT scanners, MRI equipment, and laser treatments, to the design, creation, and implementation of artificial body parts, the field of biomedical engineering has significantly contributed to mankind. Biomedical engineering has facilitated many of the latest developments surrounding human mobility, with advancement in mobility aids improving human movement for people with compromised mobility either caused by an injury or health condition. A review of the literature indicated that mobility aids, especially walking sticks, and appropriate training for their use, are generally prescribed by allied health professionals (AHP) to walking stick users for rehabilitation and activities of daily living (ADL). However, feedback from AHP is limited to the clinical environment, leaving walking stick users vulnerable to falls and injuries due to incorrect usage. Hence, to mitigate the risk of falls and injuries, and to facilitate a routine appraisal of individual patient’s usage, a simple, portable, robust, and reliable tool was developed which provides the walking stick users with real-time feedback upon incorrect usage during their activities of daily living (ADL).
This thesis aimed to design and develop a smart walking stick technology: Biofeedback stick technology (BfT). The design incorporates the approach of patient and public involvement (PPI) in the development of BfT to ensure that BfT was developed as per the requirements of walking stick users and AHP recommendations. The newly developed system was tested quantitatively for; validity, reliability, and reproducibility against gold standard equipment such as the 3D motion capture system, force plates, optical measurement system for orientation, weight bearing, and step count. The system was also tested qualitatively for its usability by conducting semi-informal interviews with AHPs and walking stick users. The results of these studies showed that the newly developed system has good accuracy, reported above 95% with a maximum inaccuracy of 1°. The data reported indicates good reproducibility. The angles, weight, and steps recorded by the system during experiments are within the values published in the literature. From these studies, it was concluded that, BfT has the potential to improve the lives of walking stick users and that, with few additional improvements, appropriate approval from relevant regulatory bodies, and robust clinical testing, the technology has a huge potential to carve its way to a commercial market
Psychological and care impact of the daily use of a pediatric gait exoskeleton in children with spinal muscular atrophy
Introducción: La Atrofia Muscular Espinal Tipo II, es una enfermedad neurodegenerativa de origen genético que cursa con debilidad muscular y provoca deterioro motor e incapacidad para caminar en los niños. Se relaciona con graves problemas respiratorios, musculoesqueléticos, gastrointestinales y otros de salud y cuidado. Los exoesqueletos robóticos de miembros inferiores son dispositivos médicos que ayudan a la marcha de pacientes que no pueden caminar. Nuestro objetivo fue evaluar el impacto en la dimensión psicológica y de autocuidado derivado del uso del exoesqueleto ATLAS en el hogar en niños con Atrofia Muscular Espinal Tipo II. Metodología: tres niños con Atrofia Muscular Espinal Tipo II utilizaron el exoesqueleto en casa cinco días a la semana durante un período de dos meses para caminar y realizar actividades. Se realizó una evaluación del autocuidado de enfermería antes y durante el uso del dispositivo para evaluar los cambios en los resultados del autocuidado y los diagnósticos de enfermería. Se realizaron entrevistas en profundidad y semiestructuradas, además de la observación durante las sesiones, para evaluar el impacto de la experiencia en la dimensión psicológica de los participantes. Resultados: el uso del exoesqueleto produjo cambios en los condicionantes básicos de los niños y una mejora en los organismos de autocuidado. También aparecieron nuevas demandas de autocuidado. Tres de los diez diagnósticos de enfermería fueron resueltos. Asimismo, los niños mostraron una buena tolerancia a la actividad además de una mejora funcional evaluada en el tercer participante. Los niños y los cuidadores principales valoraron la experiencia como positiva y significativa. Los niños tenían una mayoría de emociones positivas, y se incrementó su autonomía y comportamiento social y exploratorio. Conclusiones: la tecnología del exoesqueleto podría considerarse como un nuevo recurso para el cuidado de niños con enfermedades neuromusculares. Su uso tuvo un impacto positivo tanto en las variables de autocuidado como en la dimensión psicológica de tres niños con atrofia muscular espinal tipo II. Aunque este estudio aporta ya evidencia, más estudios sobre el tema aportarían un mayor conocimiento
Measuring spectrally resolved information processing in neural data
Background:
The human brain, an incredibly complex biological system comprising billions of neurons and trillions of synapses, possesses remarkable capabilities for information processing and distributed computations. Neurons, the fundamental building blocks, perform elementary operations on their inputs and collaborate extensively to execute intricate computations, giving rise to cognitive functions and behavior.
Notably, distributed information processing in the brain heavily relies on rhythmic neural activity characterized by synchronized oscillations at specific frequencies.
These oscillations play a crucial role in coordinating brain activity and facilitating communication between different neural circuits [1], effectively acting as temporal windows that enable efficient information exchange within specific frequency ranges.
To understand distributed information processing in neural systems, breaking down its components, i.e., —information transfer, storage, and modification can be helpful, but requires precise mathematical definitions for each respective component. Thankfully, these definitions have recently become available [2]. Information theory is a natural choice for measuring information processing, as it offers a mathematically
complete description of the concept of information and communication. The fundamental information-processing operations, are considered essential prerequisites for achieving universal information processing in any system [3]. By quantifying and analyzing these operations, we gain valuable insights into the brain’s complex computation and cognitive abilities. As information processing in the brain is intricately tied to rhythmic behavior, there is a need to establish a connection between information theoretic measures and frequency components. Previous attempts to achieve frequency-resolved information theoretic measures have mostly relied on narrowband filtering [4], which comes with several known issues of phase shifting and high false positive rate results [5],
or simplifying the computation to few variables [6], that might result in missing important information in the analysed brain signals. Therefore, the current work aims to establish a frequency-resolved measure of two crucial components of information processing: information transfer and information storage. By proposing methodological advancements, this research seeks to shed light on the role of neural oscillations in information processing within the brain. Furthermore, a more comprehensive investigation was carried out on the communication between two critical brain regions responsible for motor inhibition in the frontal cortex (right Inferior Frontal gyrus (rIFG) and pre-Supplementary motor cortex (pre-SMA)). Here, neural oscillations in the beta band (12 − 30 Hz) have been proposed to have a pivotal role in response inhibition. A long-standing question in the field was to disentangle which of these two brain areas first signals the stopping process and drives the other
[7]. Furthermore, it was hypothesized that beta oscillations carry the information transfer between these regions.
The present work addresses the methodological problems and investigates spectral information processing in neural data, in three studies.
Study 1 focuses on the critical role of information transfer, measured by transfer entropy, in distributed computation. Understanding the patterns of information transfer is essential for unraveling the computational algorithms in complex systems, such as the brain. As many natural systems rely on rhythmic processes for distributed computations, a frequency-resolved measure of information transfer becomes highly valuable. To address this, a novel algorithm is presented, efficiently
identifying frequencies responsible for sending and receiving information in a network.
The approach utilizes the invertible maximum overlap discrete wavelet transform (MODWT) to create surrogate data for computing transfer entropy, eliminating issues associated with phase shifts and filtering. However, measuring frequency-resolved information transfer poses a Partial information decomposition problem [8] that is yet to be fully resolved. The algorithm’s performance is validated using simulated data and applied to human magnetoencephalography (MEG) and ferret
local field potential recordings (LFP). In human MEG, the study unveils a complex spectral configuration of cortical information transmission, showing top-down information flow from very high frequencies (above 100Hz) to both similarly high frequencies and frequencies around 20Hz in the temporal cortex. Contrary to the current assumption, the findings suggest that low frequencies do not solely send information to high frequencies. In the ferret LFP, the prefrontal cortex demonstrates
the transmission of information at low frequencies, specifically within the range of 4-8 Hz. On the receiving end, V1 exhibits a preference for operating at very high frequency > 125 Hz. The spectrally resolved transfer entropy promises to deepen our understanding of rhythmic information exchange in natural systems, shedding light on the computational properties of oscillations on cognitive functions.
In study 2, the primary focus lay on the second fundamental aspect of information processing: the active information storage (AIS). The AIS estimates how much information in the next measurements of the process can be predicted by examining its paste state. In processes that either produce little information (low entropy) or that are highly unpredictable, the AIS is low, whereas processes that are predictable but visit many different states with equal probabilities, exhibit high AIS [9]. Within this context, we introduced a novel spectrally-resolved AIS. Utilizing intracortical recordings of neural activity in anesthetized ferrets before and after loss of consciousness (LOC), the study reveals that the modulation of AIS by anesthesia is highly specific to different frequency bands, cortical layers, and brain regions. The findings reveal that the effects of anesthesia on AIS are prominent in the supragranular
layers for the high/low gamma band, while the alpha/beta band exhibits the strongest decrease in AIS at infragranular layers, in accordance with the predictive coding theory. Additionally, the isoflurane impacts local information processing in a frequency-specific manner. For instance, increases in isoflurane concentration lead to a decrease in AIS in the alpha frequency but to an increase in AIS in the delta frequency range (<2Hz). In sum, analyzing spectrally-resolved AIS provides valuable insights into changes in cortical information processing under anesthesia.
With rhythmic neural activity playing a significant role in biological neural systems, the introduction of frequency-specific components in active information storage allows a deeper understanding of local information processing in different brain areas and under various conditions.
In study 3, to further verify the pivotal role of neural oscillations in information processing, we investigated the neural network mechanisms underlying response inhibition. A long-standing debate has centered around identifying the cortical initiator of response inhibition in the beta band, with two main regions proposed: the right rIFG and the pre-SMA. This third study aimed to determine which of these regions is activated first and exerts a potential information exchange on the other.
Using high temporal resolution magnetoencephalography (MEG) and a relatively large cohort of subjects. A significant breakthrough is achieved by demonstrating that the rIFG is activated significantly earlier than the pre-SMA. The onset of beta band activity in the rIFG occurred at around 140 ms after the STOP signal. Further analyses showed that the beta-band activity in the rIFG was crucial for successful stopping, as evidenced by its predictive value for stopping performance. Connectivity
analysis revealed that the rIFG sends information in the beta band to the pre-SMA but not vice versa, emphasizing the rIFG’s dominance in the response inhibition process. The results provide strong support for the hypothesis that the rIFG initiates stopping and utilizes beta-band oscillations for this purpose. These findings have significant implications, suggesting the possibility of spatially localized oscillation based
interventions for response inhibition.
Conclusion:
In conclusion, the present work proposes a novel algorithm for uncovering the frequencies at which information is transferred between sources and targets in the brain, providing valuable insights into the computational dynamics of neural processes. The spectrally resolved transfer entropy was successfully applied to experimental neural data of intracranial recordings in ferrets and MEG recordings of humans. Furthermore, the study on active information storage (AIS) analysis
under anesthesia revealed that the spectrally resolved AIS offers unique additional insights beyond traditional spectral power analysis. By examining changes in neural information processing, the study demonstrates how AIS analysis can deepen the understanding of anesthesia’s effects on cortical information processing. Moreover,
the third study’s findings provide strong evidence supporting the critical role of beta oscillations in information processing, particularly in response inhibition. The research successfully demonstrates that beta oscillations in the rIFG functions as the key initiator of the response inhibition process, acting as a top-down control mechanism. The identification of beta oscillations as a crucial factor in information
processing opens possibilities for further research and targeted interventions in neurological disorders. Taken together, the current work highlights the role of spectrally-resolved information processing in neural systems by not only introducing novel algorithms, but also successfully applying them to experimental oscillatory neural activity in relation to low-level cortical information processing (anesthesia)
as well as high-level processes (cognitive response inhibition)
Virtual reality obstacle crossing: adaptation, retention and transfer to the physical world
Virtual reality (VR) paradigms are increasingly being used in movement and exercise sciences with the aim to enhance motor function and stimulate motor adaptation in healthy and pathological conditions. Locomotor training based in VR may be promising for motor skill learning, with transfer of VR skills to the physical world in turn required to benefit functional activities of daily life. This PhD project aims to examine locomotor adaptations to repeated VR obstacle crossing in healthy young adults as well as transfers to the untrained limb and the physical world, and retention potential of the learned skills. For these reasons, the current thesis comprises three studies using controlled VR obstacle crossing interventions during treadmill walking.
In the first and second studies we investigated adaptation to crossing unexpectedly appearing virtual obstacles, with and without feedback about crossing performance, and its transfer to the untrained leg. In the third study we investigated transfer of virtual obstacle crossing to physical obstacles of similar size to the virtual ones, that appeared at the same time point within the gait cycle. We also investigated whether the learned skills can be retained in each of the environments over one week. In all studies participants were asked to walk on a treadmill while wearing a VR headset that represented their body as an avatar via real-time synchronised optical motion capture. Participants had to cross virtual and/or physical obstacles with and without feedback about their crossing performance. If applicable, feedback was provided based on motion capture immediately after virtual obstacle crossing. Toe clearance, margin of stability, and lower extremity joint angles in the sagittal plane were calculated for the crossing legs to analyse adaptation, transfer, and retention of obstacle crossing performance.
The main outcomes of the first and second studies were that crossing multiple virtual obstacles increased participants’ dynamic stability and led to a nonlinear adaptation of toe clearance that was enhanced by visual feedback about crossing performance. However, independent of the use of feedback, no transfer to the untrained leg was detected. Moreover, despite significant and rapid adaptive changes in locomotor kinematics with repeated VR obstacle crossing, results of the third study revealed limited transfer of learned skills from virtual to physical obstacles. Lastly, despite full retention over one week in the virtual environment we found only partial retention when crossing a physical obstacle while walking on the treadmill.
In summary, the findings of this PhD project confirmed that repeated VR obstacle perturbations can effectively stimulate locomotor skill adaptations. However, these are not transferable to the untrained limb irrespective of enhanced awareness and feedback. Moreover, the current data provide evidence that, despite significant adaptive changes in locomotion kinematics with repeated practice of obstacle crossing under VR conditions, transfer to and retention in the physical environment is limited. It may be that perception-action coupling in the virtual environment, and thus sensorimotor coordination, differs from the physical world, potentially inhibiting retained transfer between those two conditions. Accordingly, VR-based locomotor skill training paradigms need to be considered carefully if they are to replace training in the physical world
Learning to Assist Different Wearers in Multitasks: Efficient and Individualized Human-In-the-Loop Adaption Framework for Exoskeleton Robots
One of the typical purposes of using lower-limb exoskeleton robots is to
provide assistance to the wearer by supporting their weight and augmenting
their physical capabilities according to a given task and human motion
intentions. The generalizability of robots across different wearers in multiple
tasks is important to ensure that the robot can provide correct and effective
assistance in actual implementation. However, most lower-limb exoskeleton
robots exhibit only limited generalizability. Therefore, this paper proposes a
human-in-the-loop learning and adaptation framework for exoskeleton robots to
improve their performance in various tasks and for different wearers. To suit
different wearers, an individualized walking trajectory is generated online
using dynamic movement primitives and Bayes optimization. To accommodate
various tasks, a task translator is constructed using a neural network to
generalize a trajectory to more complex scenarios. These generalization
techniques are integrated into a unified variable impedance model, which
regulates the exoskeleton to provide assistance while ensuring safety. In
addition, an anomaly detection network is developed to quantitatively evaluate
the wearer's comfort, which is considered in the trajectory learning procedure
and contributes to the relaxation of conflicts in impedance control. The
proposed framework is easy to implement, because it requires proprioceptive
sensors only to perform and deploy data-efficient learning schemes. This makes
the exoskeleton practical for deployment in complex scenarios, accommodating
different walking patterns, habits, tasks, and conflicts. Experiments and
comparative studies on a lower-limb exoskeleton robot are performed to
demonstrate the effectiveness of the proposed framework.Comment: 16 pages journal articl
ATHENA Research Book, Volume 2
ATHENA European University is an association of nine higher education institutions with the mission of promoting excellence in research and innovation by enabling international cooperation. The acronym ATHENA stands for Association of Advanced Technologies in Higher Education. Partner institutions are from France, Germany, Greece, Italy, Lithuania, Portugal and Slovenia: University of Orléans, University of Siegen, Hellenic Mediterranean University, Niccolò Cusano University, Vilnius Gediminas Technical University, Polytechnic Institute of Porto and University of Maribor. In 2022, two institutions joined the alliance: the Maria Curie-Skłodowska University from Poland and the University of Vigo from Spain. Also in 2022, an institution from Austria joined the alliance as an associate member: Carinthia University of Applied Sciences. This research book presents a selection of the research activities of ATHENA University's partners. It contains an overview of the research activities of individual members, a selection of the most important bibliographic works of members, peer-reviewed student theses, a descriptive list of ATHENA lectures and reports from individual working sections of the ATHENA project. The ATHENA Research Book provides a platform that encourages collaborative and interdisciplinary research projects by advanced and early career researchers
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