Combining brain-computer interfaces and assistive technologies: state-of-the-art and challenges

In recent years, new research has brought the field of EEG-based Brain-Computer Interfacing (BCI) out of its infancy and into a phase of relative maturity through many demonstrated prototypes such as brain-controlled wheelchairs, keyboards, and computer games. With this proof-of-concept phase in the past, the time is now ripe to focus on the development of practical BCI technologies that can be brought out of the lab and into real-world applications. In particular, we focus on the prospect of improving the lives of countless disabled individuals through a combination of BCI technology with existing assistive technologies (AT). In pursuit of more practical BCIs for use outside of the lab, in this paper, we identify four application areas where disabled individuals could greatly benefit from advancements in BCI technology, namely,“Communication and Control”, “Motor Substitution”, “Entertainment”, and “Motor Recovery”. We review the current state of the art and possible future developments, while discussing the main research issues in these four areas. In particular, we expect the most progress in the development of technologies such as hybrid BCI architectures, user-machine adaptation algorithms, the exploitation of users’ mental states for BCI reliability and confidence measures, the incorporation of principles in human-computer interaction (HCI) to improve BCI usability, and the development of novel BCI technology including better EEG devices

Bio Mind and Techno Nature in the Performance of Memory: Arts-Based-Research and Human Enhancement

This paper intends to examine two recent projects Enhancing the Mind’s I and Emerging Self that address notions of self-identity, the desire for freedom of form and the greater cognitive capacities promised by neuro-enhancement technologies. It is a bid on critical evaluation of the production of the artworks; departing from an understanding that the observer is not independent of reality and that observation and experience are constructed. Consciousness is considered as resulting from the organism capacities to understand its emotions and interacting context, thus the research explores the possibilities that memory and knowledge do not reflect a real exterior world, but a concrete interior world attempting to play with possibilities to generate affect and empathy in the audiences. The text reflects on the ethical side of Human Enhancement (i.e. the potentiation of biological characteristics of Human Body) and the technologies, such as Brain Computer Interaction (BCI) or digital tattoos (tattoos that have technological interactive properties), promising a refinement of nature by technology. It raises questions surrounding memory and identity through art installation. It explores whether is it possible to translate one’s emotions directly into matter, as a memory. The result is the opening of a critical gap between the way sciences produce knowledge about the subject and the affect produced by the experience of the viewer on the installation artworks

Brain computer interfaces: an engineering view. Design, implementation and test of a SSVEP-based BCI.

This thesis presents the realization of a compact, yet flexible BCI platform, which, when compared to most commercially-available solution, can offer an optimal trade-off between the following requirements: (i) minimal, easy experimental setup; (ii) flexibility, allowing simultaneous studies on other bio-potentials; (iii) cost effectiveness (e.g. < 1000 €); (iv) robust design, suitable for operation outside lab environments. The thesis encompasses all the project phases, from hardware design and realization, up to software and signal processing. The work started from the development of the hardware acquisition unit. It resulted in a compact, battery-operated module, whose medium-to-large scale production costs are in the range of 300 €. The module features 16 input channels and can be used to acquire different bio-potentials, including EEG, EMG, ECG. Module performance is very good (RTI noise < 1.3 uVpp), and was favourably compared against a commercial device (g.tec USBamp). The device was integrated into an ad-hoc developed Matlab-based platform, which handles the hardware control, as well as the data streaming, logging and processing. Via a specifically developed plug-in, incoming data can also be streamed to a TOBI-interface compatible system. As a demonstrator, the BCI was developed for AAL (Ambient Assisted Living) system-control purposes, having in mind the following requirements: (i) online, self-paced BCI operation (i.e., the BCI monitors the EEG in real-time and must discern between intentional control periods, and non-intentional, rest ones, interpreting the user’s intent only in the first case); (ii) calibration-free approach (“ready-to-use”, “Plug&Play”); (iii) subject-independence (general approach). The choice of the BCI operating paradigm fell on Steady State visual Evoked Potential (SSVEP). Two offline SSVEP classification algorithms were proposed and compared against reference literature, highlighting good performance, especially in terms of lower computational complexity. A method for improving classification accuracy was presented, suitable for use in online, self-paced scenarios (since it can be used to discriminate between intentional control periods and non-intentional ones). Results show a very good performance, in particular in terms of false positives immunity (0.26 min^-1), significantly improving over the state of the art. The whole BCI setup was tested both in lab condition, as well as in relatively harsher ones (in terms of environmental noise and non-idealities), such as in the context of the Handimatica 2014 exhibition. In both cases, a demonstrator allowing control of home appliances through BCI was developed

Workload-aware systems and interfaces for cognitive augmentation

In today's society, our cognition is constantly influenced by information intake, attention switching, and task interruptions. This increases the difficulty of a given task, adding to the existing workload and leading to compromised cognitive performances. The human body expresses the use of cognitive resources through physiological responses when confronted with a plethora of cognitive workload. This temporarily mobilizes additional resources to deal with the workload at the cost of accelerated mental exhaustion. We predict that recent developments in physiological sensing will increasingly create user interfaces that are aware of the user’s cognitive capacities, hence able to intervene when high or low states of cognitive workload are detected. In this thesis, we initially focus on determining opportune moments for cognitive assistance. Subsequently, we investigate suitable feedback modalities in a user-centric design process which are desirable for cognitive assistance. We present design requirements for how cognitive augmentation can be achieved using interfaces that sense cognitive workload. We then investigate different physiological sensing modalities to enable suitable real-time assessments of cognitive workload. We provide empirical evidence that the human brain is sensitive to fluctuations in cognitive resting states, hence making cognitive effort measurable. Firstly, we show that electroencephalography is a reliable modality to assess the mental workload generated during the user interface operation. Secondly, we use eye tracking to evaluate changes in eye movements and pupil dilation to quantify different workload states. The combination of machine learning and physiological sensing resulted in suitable real-time assessments of cognitive workload. The use of physiological sensing enables us to derive when cognitive augmentation is suitable. Based on our inquiries, we present applications that regulate cognitive workload in home and work settings. We deployed an assistive system in a field study to investigate the validity of our derived design requirements. Finding that workload is mitigated, we investigated how cognitive workload can be visualized to the user. We present an implementation of a biofeedback visualization that helps to improve the understanding of brain activity. A final study shows how cognitive workload measurements can be used to predict the efficiency of information intake through reading interfaces. Here, we conclude with use cases and applications which benefit from cognitive augmentation. This thesis investigates how assistive systems can be designed to implicitly sense and utilize cognitive workload for input and output. To do so, we measure cognitive workload in real-time by collecting behavioral and physiological data from users and analyze this data to support users through assistive systems that adapt their interface according to the currently measured workload. Our overall goal is to extend new and existing context-aware applications by the factor cognitive workload. We envision Workload-Aware Systems and Workload-Aware Interfaces as an extension in the context-aware paradigm. To this end, we conducted eight research inquiries during this thesis to investigate how to design and create workload-aware systems. Finally, we present our vision of future workload-aware systems and workload-aware interfaces. Due to the scarce availability of open physiological data sets, reference implementations, and methods, previous context-aware systems were limited in their ability to utilize cognitive workload for user interaction. Together with the collected data sets, we expect this thesis to pave the way for methodical and technical tools that integrate workload-awareness as a factor for context-aware systems.Tagtäglich werden unsere kognitiven Fähigkeiten durch die Verarbeitung von unzähligen Informationen in Anspruch genommen. Dies kann die Schwierigkeit einer Aufgabe durch mehr oder weniger Arbeitslast beeinflussen. Der menschliche Körper drückt die Nutzung kognitiver Ressourcen durch physiologische Reaktionen aus, wenn dieser mit kognitiver Arbeitsbelastung konfrontiert oder überfordert wird. Dadurch werden weitere Ressourcen mobilisiert, um die Arbeitsbelastung vorübergehend zu bewältigen. Wir prognostizieren, dass die derzeitige Entwicklung physiologischer Messverfahren kognitive Leistungsmessungen stets möglich machen wird, um die kognitive Arbeitslast des Nutzers jederzeit zu messen. Diese sind in der Lage, einzugreifen wenn eine zu hohe oder zu niedrige kognitive Belastung erkannt wird. Wir konzentrieren uns zunächst auf die Erkennung passender Momente für kognitive Unterstützung welche sich der gegenwärtigen kognitiven Arbeitslast bewusst sind. Anschließend untersuchen wir in einem nutzerzentrierten Designprozess geeignete Feedbackmechanismen, die zur kognitiven Assistenz beitragen. Wir präsentieren Designanforderungen, welche zeigen wie Schnittstellen eine kognitive Augmentierung durch die Messung kognitiver Arbeitslast erreichen können. Anschließend untersuchen wir verschiedene physiologische Messmodalitäten, welche Bewertungen der kognitiven Arbeitsbelastung in Realzeit ermöglichen. Zunächst validieren wir empirisch, dass das menschliche Gehirn auf kognitive Arbeitslast reagiert. Es zeigt sich, dass die Ableitung der kognitiven Arbeitsbelastung über Elektroenzephalographie eine geeignete Methode ist, um den kognitiven Anspruch neuartiger Assistenzsysteme zu evaluieren. Anschließend verwenden wir Eye-Tracking, um Veränderungen in den Augenbewegungen und dem Durchmesser der Pupille unter verschiedenen Intensitäten kognitiver Arbeitslast zu bewerten. Das Anwenden von maschinellem Lernen führt zu zuverlässigen Echtzeit-Bewertungen kognitiver Arbeitsbelastung. Auf der Grundlage der bisherigen Forschungsarbeiten stellen wir Anwendungen vor, welche die Kognition im häuslichen und beruflichen Umfeld unterstützen. Die physiologischen Messungen stellen fest, wann eine kognitive Augmentierung sich als günstig erweist. In einer Feldstudie setzen wir ein Assistenzsystem ein, um die erhobenen Designanforderungen zur Reduktion kognitiver Arbeitslast zu validieren. Unsere Ergebnisse zeigen, dass die Arbeitsbelastung durch den Einsatz von Assistenzsystemen reduziert wird. Im Anschluss untersuchen wir, wie kognitive Arbeitsbelastung visualisiert werden kann. Wir stellen eine Implementierung einer Biofeedback-Visualisierung vor, die das Nutzerverständnis zum Verlauf und zur Entstehung von kognitiver Arbeitslast unterstützt. Eine abschließende Studie zeigt, wie Messungen kognitiver Arbeitslast zur Vorhersage der aktuellen Leseeffizienz benutzt werden können. Wir schließen hierbei mit einer Reihe von Applikationen ab, welche sich kognitive Arbeitslast als Eingabe zunutze machen. Die vorliegende wissenschaftliche Arbeit befasst sich mit dem Design von Assistenzsystemen, welche die kognitive Arbeitslast der Nutzer implizit erfasst und diese bei der Durchführung alltäglicher Aufgaben unterstützt. Dabei werden physiologische Daten erfasst, um Rückschlüsse in Realzeit auf die derzeitige kognitive Arbeitsbelastung zu erlauben. Anschließend werden diese Daten analysiert, um dem Nutzer strategisch zu assistieren. Das Ziel dieser Arbeit ist die Erweiterung neuartiger und bestehender kontextbewusster Benutzerschnittstellen um den Faktor kognitive Arbeitslast. Daher werden in dieser Arbeit arbeitslastbewusste Systeme und arbeitslastbewusste Benutzerschnittstellen als eine zusätzliche Dimension innerhalb des Paradigmas kontextbewusster Systeme präsentiert. Wir stellen acht Forschungsstudien vor, um die Designanforderungen und die Implementierung von kognitiv arbeitslastbewussten Systemen zu untersuchen. Schließlich stellen wir unsere Vision von zukünftigen kognitiven arbeitslastbewussten Systemen und Benutzerschnittstellen vor. Durch die knappe Verfügbarkeit öffentlich zugänglicher Datensätze, Referenzimplementierungen, und Methoden, waren Kontextbewusste Systeme in der Auswertung kognitiver Arbeitslast bezüglich der Nutzerinteraktion limitiert. Ergänzt durch die in dieser Arbeit gesammelten Datensätze erwarten wir, dass diese Arbeit den Weg für methodische und technische Werkzeuge ebnet, welche kognitive Arbeitslast als Faktor in das Kontextbewusstsein von Computersystemen integriert

Upper-limb Kinematic Analysis and Artificial Intelligent Techniques for Neurorehabilitation and Assistive Environments

Stroke, one of the leading causes of death and disability around the world, usually affects the motor cortex causing weakness or paralysis in the limbs of one side of the body. Research efforts in neurorehabilitation technology have focused on the development of robotic devices to restore motor and cognitive function in impaired individuals, having the potential to deliver high-intensity and motivating therapy. End-effector-based devices have become an usual tool in the upper- limb neurorehabilitation due to the ease of adapting to patients. However, they are unable to measure the joint movements during the exercise. Thus, the first part of this thesis is focused on the development of a kinematic reconstruction algorithm that can be used in a real rehabilitation environment, without disturbing the normal patient-clinician interaction. On the basis of the algorithm found in the literature that presents some instabilities, a new algorithm is developed. The proposed algorithm is the first one able to online estimate not only the upper-limb joints, but also the trunk compensation using only two non-invasive wearable devices, placed onto the shoulder and upper arm of the patient. This new tool will allow the therapist to perform a comprehensive assessment combining the range of movement with clinical assessment scales. Knowing that the intensity of the therapy improves the outcomes of neurorehabilitation, a ‘self-managed’ rehabilitation system can allow the patients to continue the rehabilitation at home. This thesis proposes a system to online measure a set of upper-limb rehabilitation gestures, and intelligently evaluates the quality of the exercise performed by the patients. The assessment is performed through the study of the performed movement as a whole as well as evaluating each joint independently. The first results are promising and suggest that this system can became a a new tool to complement the clinical therapy at home and improve the rehabilitation outcomes. Finally, severe motor condition can remain after rehabilitation process. Thus, a technology solution for these patients and people with severe motor disabilities is proposed. An intelligent environmental control interface is developed with the ability to adapt its scan control to the residual capabilities of the user. Furthermore, the system estimates the intention of the user from the environmental information and the behavior of the user, helping in the navigation through the interface, improving its independence at home.El accidente cerebrovascular o ictus es una de las causas principales de muerte y discapacidad a nivel mundial. Normalmente afecta a la corteza motora causando debilidad o parálisis en las articulaciones del mismo lado del cuerpo. Los esfuerzos de investigación dentro de la tecnología de neurorehabilitación se han centrado en el desarrollo de dispositivos robóticos para restaurar las funciones motoras y cognitivas en las personas con esta discapacidad, teniendo un gran potencial para ofrecer una terapia de alta intensidad y motivadora. Los dispositivos basados en efector final se han convertido en una herramienta habitual en la neurorehabilitación de miembro superior ya que es muy sencillo adaptarlo a los pacientes. Sin embargo, éstos no son capaces de medir los movimientos articulares durante la realización del ejercicio. Por tanto, la primera parte de esta tesis se centra en el desarrollo de un algoritmo de reconstrucción cinemática que pueda ser usado en un entorno de rehabilitación real, sin perjudicar a la interacción normal entre el paciente y el clínico. Partiendo de la base que propone el algoritmo encontrado en la literatura, el cual presenta algunas inestabilidades, se ha desarrollado un nuevo algoritmo. El algoritmo propuesto es el primero capaz de estimar en tiempo real no sólo las articulaciones del miembro superior, sino también la compensación del tronco usando solamente dos dispositivos no invasivos y portátiles, colocados sobre el hombro y el brazo del paciente. Esta nueva herramienta permite al terapeuta realizar una valoración más exhaustiva combinando el rango de movimiento con las escalas de valoración clínicas. Sabiendo que la intensidad de la terapia mejora los resultados de la recuperación del ictus, un sistema de rehabilitación ‘auto-gestionado’ permite a los pacientes continuar con la rehabilitación en casa. Esta tesis propone un sistema para medir en tiempo real un conjunto de gestos de miembro superior y evaluar de manera inteligente la calidad del ejercicio realizado por el paciente. La valoración se hace a través del estudio del movimiento ejecutado en su conjunto, así como evaluando cada articulación independientemente. Los primeros resultados son prometedores y apuntan a que este sistema puede convertirse en una nueva herramienta para complementar la terapia clínica en casa y mejorar los resultados de la rehabilitación. Finalmente, después del proceso de rehabilitación pueden quedar secuelas motoras graves. Por este motivo, se propone una solución tecnológica para estas personas y para personas con discapacidades motoras severas. Así, se ha desarrollado una interfaz de control de entorno inteligente capaz de adaptar su control a las capacidades residuales del usuario. Además, el sistema estima la intención del usuario a partir de la información del entorno y el comportamiento del usuario, ayudando en la navegación a través de la interfaz, mejorando su independencia en el hogar

A unified methodology for heartbeats detection in seismocardiogram and ballistocardiogram signals

This work presents a methodology to analyze and segment both seismocardiogram (SCG) and ballistocardiogram (BCG) signals in a unified fashion. An unsupervised approach is followed to extract a template of SCG/BCG heartbeats, which is then used to fine-tune temporal waveform annotation. Rigorous performance assessment is conducted in terms of sensitivity, precision, Root Mean Square Error (RMSE) and Mean Absolute Error (MAE) of annotation. The methodology is tested on four independent datasets, covering different measurement setups and time resolutions. A wide application range is therefore explored, which better characterizes the robustness and generality of the method with respect to a single dataset. Overall, sensitivity and precision scores are uniform across all datasets (p &gt; 0.05 from the Kruskal–Wallis test): the average sensitivity among datasets is 98.7%, with 98.2% precision. On the other hand, a slight yet significant difference in RMSE and MAE scores was found (p &lt; 0.01) in favor of datasets with higher sampling frequency. The best RMSE scores for SCG and BCG are 4.5 and 4.8 ms, respectively; similarly, the best MAE scores are 3.3 and 3.6 ms. The results were compared to relevant recent literature and are found to improve both detection performance and temporal annotation errors

A Human-Machine Interface Based on Eye Tracking for Controlling and Monitoring a Smart Home Using the Internet of Things

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