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

A wireless sEMG-based body-machine interface for assistive technology devices

Assistive technology (AT) tools and appliances are being more and more widely used and developed worldwide to improve the autonomy of people living with disabilities and ease the interaction with their environment. This paper describes an intuitive and wireless surface electromyography (sEMG) based body-machine interface for AT tools. Spinal cord injuries at C5-C8 levels affect patients' arms, forearms, hands, and fingers control. Thus, using classical AT control interfaces (keypads, joysticks, etc.) is often difficult or impossible. The proposed system reads the AT users' residual functional capacities through their sEMG activity, and converts them into appropriate commands using a threshold-based control algorithm. It has proven to be suitable as a control alternative for assistive devices and has been tested with the JACO arm, an articulated assistive device of which the vocation is to help people living with upper-body disabilities in their daily life activities. The wireless prototype, the architecture of which is based on a 3-channel sEMG measurement system and a 915-MHz wireless transceiver built around a low-power microcontroller, uses low-cost off-the-shelf commercial components. The embedded controller is compared with JACO's regular joystick-based interface, using combinations of forearm, pectoral, masseter, and trapeze muscles. The measured index of performance values is 0.88, 0.51, and 0.41 bits/s, respectively, for correlation coefficients with the Fitt's model of 0.75, 0.85, and 0.67. These results demonstrate that the proposed controller offers an attractive alternative to conventional interfaces, such as joystick devices, for upper-body disabled people using ATs such as JACO

A concept-environment for computer-based augmentative and alternative communication founded on a systematic review

Introduction: locked-In Syndrome is admittedly the worst case of motor and speech impairment, it seriously damages the ability of oral and gestural communication of patients. In recent years, alternative and augmentative communication technology has provided resources to restore these patients' ability to communicate. Methods: in order to relate and classify the main methods with that purpose, this work conducted a systematic review on several journal databases. Results: we found 203 related papers and 55 of them were selected to compose the study. After that, we classified them into three major groups and we identified the main difficulties when using each approach. Conclusion: in order to overcome these difficulties, we propose a new system concept to develop an adaptive, robust and low cost communication environment. The proposed system is composed of five modules: data entry, communication, aid to the caregiver and external interaction

Human-machine interface for two-dimensional steering control with the auricular muscles

Human-machine interfaces (HMIs) can be used to decode a user's motor intention to control an external device. People that suffer from motor disabilities, such as spinal cord injury, can benefit from the uses of these interfaces. While many solutions can be found in this direction, there is still room for improvement both from a decoding, hardware, and subject-motor learning perspective. Here we show, in a series of experiments with non-disabled participants, a novel decoding and training paradigm allowing naïve participants to use their auricular muscles (AM) to control two degrees of freedom with a virtual cursor. AMs are particularly interesting because they are vestigial muscles and are often preserved after neurological diseases. Our method relies on the use of surface electromyographic records and the use of contraction levels of both AMs to modulate the velocity and direction of a cursor in a two-dimensional paradigm. We used a locking mechanism to fix the current position of each axis separately to enable the user to stop the cursor at a certain location. A five-session training procedure (20–30 min per session) with a 2D center-out task was performed by five volunteers. All participants increased their success rate (Initial: 52.78 ± 5.56%; Final: 72.22 ± 6.67%; median ± median absolute deviation) and their trajectory performances throughout the training. We implemented a dual task with visual distractors to assess the mental challenge of controlling while executing another task; our results suggest that the participants could perform the task in cognitively demanding conditions (success rate of 66.67 ± 5.56%). Finally, using the Nasa Task Load Index questionnaire, we found that participants reported lower mental demand and effort in the last two sessions. To summarize, all subjects could learn to control the movement of a cursor with two degrees of freedom using their AM, with a low impact on the cognitive load. Our study is a first step in developing AM-based decoders for HMIs for people with motor disabilities, such as spinal cord injury

Assistive technologies as rights enablers

The Convention on the Rights of the Child and the Convention on the Rights of Persons with Disability establish the rights for all children. For some children, enjoying those rights depends on or is facilitated by assistive technology, that is, products adapted or designed for improving the functioning of disabled people and all services inherent to the selection, acquisition, and use of assistive products. This chapter reviews the definition of assistive technology and briefly describes assistive products categories to show the breadth of assistive products available. It then discusses children rights and how they can be mediated or moderated by assistive technologies. Some of the challenges and ethical issues of assistive technology provision for children are also examined.info:eu-repo/semantics/publishedVersio

Review of Assistive Devices for Electric Powered Wheelchairs Navigation

The decreasing costs of microprocessor systems and increasing range of “Smart Sensors” have led to a boom in Assistive Device Technology. The annual rate of expenditure for mobility related devices has reached $1 billion dollars in the United States alone. The industries current focus is to develop a wider range of Independent Mobility Controllers to allow, even the most severely disabled person, the ability to control an Electric Powered Wheelchair (EPW). Advances in Autonomous Robot Design have led to corresponding improvements in EPW technology. This paper outlines user interfaces and input device technologies used at present to navigate an EPW

Analysis of a Sorter Cascade Applied to Control a Wheelchair

The precise eye state detection is a fundamental stage for various activities that require human-machine interaction (HMI). This chapter presents an analysis of the implementation of a system for navigating a wheelchair with automation (CRA), based on facial expressions, especially eyes closed using a Haar cascade classifier (HCC). Aimed at people with locomotor disability of the upper and lower limbs, the state detection was based on two steps: the capture of the image, which concentrates on the detection actions and image optimization; actions of the chair, which interprets the data capture and sends the action to the chair. The results showed that the model has excellent accuracy in identification with robust performance in recognizing eyes closed, bypassing well occlusion issues and lighting with about 98% accuracy. The application of the model in the simulations opens the implementation and marriage opportunity with the chair sensor universe aiming a safe and efficient navigation to the user

On Assisted Living of Paralyzed Persons through Real-Time Eye Features Tracking and Classification using Support Vector Machines

Background: The eye features like eye-blink and eyeball movements can be used as a module in assisted living systems that allow a class of physically challenged people speaks – using their eyes. The objective of this work is to design a real-time customized keyboard to be used by a physically challenged person to speak to the outside world, for example, to enable a computer to read a story or a document, do gaming and exercise of nerves, etc., through eye features tracking Method: In a paralyzed person environment, the right-left, up-down eyeball movements act like a scroll and eye blink as a nod. The eye features are tracked using Support Vector Machines (SVMs). Results: A prototype keyboard is custom-designed to work with eye-blink detection and eyeball-movement tracking using Support Vector Machines (SVMs) and tested in a typical paralyzed person-environment under varied lighting conditions. Tests performed on male and female subjects of different ages showed results with a success rate of 92%. Conclusions: Since the system needs about 2 seconds to process one command, real-time use is not required. The efficiency can be improved through the use of a depth sensor camera, faster processor environment, or motion estimation

Estratégias de controle de trajetórias para cadeira de rodas robotizadas

Orientador: Eleri CardozoDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Elétrica e de ComputaçãoResumo: Desde os anos 80, diversos trabalhos foram publicados com o objetivo de propor soluções alternativas para usuários de cadeira de rodas motorizadas com severa deficiência motora e que não possuam capacidade de operar um joystick mecânico. Dentre essas soluções estão interfaces assistivas que auxiliam no comando da cadeira de rodas através de diversos mecanismos como expressões faciais, interfaces cérebro-computador, e rastreamento de olho. Além disso, as cadeiras de rodas ganharam certa autonomia para realizar determinadas tarefas que vão de desviar de obstáculos, abrir portas e até planejar e executar rotas. Para que estas tarefas possam ser executadas, é necessário que as cadeiras de rodas tenham estruturas não convencionais, habilidade de sensoriamento do ambiente e estratégias de controle de locomoção. O objetivo principal é disponibilizar uma cadeira de rodas que ofereça conforto ao usuário e que possua um condução segura não importando o tipo de deficiência do usuário. Entretanto, durante a condução da cadeira de rodas, o desalinhamento das rodas castores podem oferecer certo perigo ao usuário, uma vez que, dependendo da maneira em que elas estejam orientadas, instabilidades podem ocorrer, culminando em acidentes. Da mesma forma, o desalinhamento das rodas castores é considerado um dos principais causadores de desvios de trajetória que ocorrem durante a movimentação da cadeira de rodas, juntamente com diferentes distribuições de pesos ou diferentes atritos entre as rodas e o chão. Nesta dissertação, é considerado apenas o desalinhamento das rodas castores como único causador de desvio de trajetória da cadeira de rodas e, dessa forma, são propostas soluções que possam reduzir ou até mesmo eliminar o efeito deste desalinhamento. Com a implementação das melhores soluções desenvolvidas neste trabalho, é possível fazer com que diversas interfaces assistivas que têm baixa taxa de comandos possam ser utilizadas, uma vez que o usuário não precisa, constantemente, corrigir o desvio da trajetória desejada. Ademais, é elaborado um novo projeto de cadeira de rodas "inteligente" para a implementação das técnicas desenvolvidas neste trabalhoAbstract: Since the 1980s several works were published proposing alternative solutions for users of powered wheelchairs with severe mobility impairments and that are not able to operate a mechanical joystick. Such solutions commonly focus on assistive interfaces that help commanding the wheelchair through distinct mechanisms such as facial expressions, brain-computer interfaces, and eye tracking. Besides that, the wheelchairs have achieved a certain level of autonomy to accomplish determined tasks such as obstacle avoidance, doors opening and even path planning and execution. For these tasks to be performed, it is necessary the wheelchairs to have a non conventional designs, ability to sense the environment and locomotion control strategies. The ultimate objective is to offer a comfortable and safe conduction no matter the user's mobility impairments. However, while driving the wheelchair, the caster wheels' misalignment might offer risks to the user, because, depending on the way they are initially oriented, instabilities may occur causing accidents. Similarly, the caster wheels' misalignment can be considered, among others like different weight distribution or different friction between wheel and floor, one of the main causes of path deviation from the intended trajectory while the wheelchair is moving. In this dissertation, it is considered the caster wheels' misalignment as the unique generator of wheelchair path deviation and, therefore, it is proposed different solutions in order to reduce or even eliminate the effects of the misalignment. The implementation of the best solutions developed in this work allows assistive interfaces with low rate of commands to be widespread, once the user does not need to, constantly, correct path deviation. Additionally, a new smart wheelchair project is elaborated for the implementation of the techniques developed in this workMestradoEngenharia de ComputaçãoMestre em Engenharia Elétrica88882.329382/2019-01CAPE