Design requirements and potential target users for brain-computer interfaces–recommendations from rehabilitation professionals

It is an implicit assumption in the field of brain-computer interfacing (BCI) that BCIs can be satisfactorily used to access augmentative and alternative communication (AAC) methods by people with severe physical disabilities. A one-day workshop and focus group interview was held to investigate this assumption. Rehabilitation professionals (N = 28) were asked to critically assess current BCI technology, recommend design requirements and identify target users. The individual answers were analyzed using the theoretical framework of grounded theory. None of the participants expressed a perception of added value of current BCIs over existing alternatives. A major criticism (and requirement) was that the usability of BCI systems should significantly improve. Target users are only those who can hardly or not at all use alternative access technologies. However, such persons often have concurrent physical, sensory, and cognitive problems, which could complicate BCI use. If successful BCI use continues to require a user to sit motionlessly and have intact cognition, then–as previously implicitly assumed–people in the locked-in state (resulting from late-stage amyotrophic lateral sclerosis, multiple sclerosis, spinal muscular atrophy type II or classic or total locked-in syndrome) and people with high spinal cord injury (C1/C2) could be target users.</p

User Experience Evaluation in BCI:Mind the Gap!

Generally brain-computer interface (BCI) systems are evaluated based on the assumption that the user is trying to perform a specific task in the most efficient way. BCI for entertainment yields interesting applications for both patients and healthy users. Then the purpose is to create positive experiences that enrich our lives. To evaluate such systems, the user experience needs to be taken into account to understand how a system can satisfy these needs. This paper points at the gap in user experience evaluation currently in BCI research, and shows how user experience evaluation could benefit BCI, through increased user acceptance, enjoyment, BCI task performance, enhanced human-computer interaction, and improved selection of suitable mental tasks in a given context

Experiencing BCI control in a popular computer game

Brain–computer interfaces (BCIs) are not only being developed to aid disabled individuals with motor substitution, motor recovery, and novel communication possibilities, but also as a modality for healthy users in entertainment and gaming. This study investigates whether the incorporation of a BCI in the popular game World of Warcraft (WoW) has effects on the user experience. A BCI control channel based on parietal alpha band power is used to control the shape and function of the avatar in the game. In the experiment, participants , a mix of experienced and inexperienced WoW players, played with and without the use of BCI in a within-subjects design. Participants themselves could indicate when they wanted to stop playing. Actual and estimated duration was recorded and questionnaires on presence and control were administered. Afterwards, oral interviews were taken. No difference in actual duration was found between conditions. Results indicate that the difference between estimated and actual duration was not related to user experience but was person specific. When using a BCI, control and involvement were rated lower. But BCI control did not significantly decrease fun. During interviews, experienced players stated that they saw potential in the application of BCIs in games with complex interfaces such as WoW. This study suggests that BCI as an additional control can be as much fun and natural to use as keyboard/mouse control, even if the amount of control is limited

Bacteria Hunt: Evaluating multi-paradigm BCI interaction

The multimodal, multi-paradigm brain-computer interfacing (BCI) game Bacteria Hunt was used to evaluate two aspects of BCI interaction in a gaming context. One goal was to examine the effect of feedback on the ability of the user to manipulate his mental state of relaxation. This was done by having one condition in which the subject played the game with real feedback, and another with sham feedback. The feedback did not seem to affect the game experience (such as sense of control and tension) or the objective indicators of relaxation, alpha activity and heart rate. The results are discussed with regard to clinical neurofeedback studies. The second goal was to look into possible interactions between the two BCI paradigms used in the game: steady-state visually-evoked potentials (SSVEP) as an indicator of concentration, and alpha activity as a measure of relaxation. SSVEP stimulation activates the cortex and can thus block the alpha rhythm. Despite this effect, subjects were able to keep their alpha power up, in compliance with the instructed relaxation task. In addition to the main goals, a new SSVEP detection algorithm was developed and evaluated

Making brain-computer interfaces better: improving usability through post-processing

Brain-computer interfaces (BCIs) allow you to control things directly with your mind. Unfortunately, such input devices based on observations of the body are plagued by noise, non-stationarities, and ambiguity. In the lab, we can protect systems somewhat from these influences, but in ‘the real world’, BCIs could use a little help. \ud How important is good control anyway? How well can users even assess their level of control? Fourteen participants evaluated three sets of mental tasks each for five weeks. Most important to them was good task recognition and easy task execution. When people know the input they provide, they have a good perception of their level of control. Eighty-seven participants played a browser game with varying levels of control. The actual amount of control explained 72% of the control they thought they had. \ud Post-processing is a simple solution to improve the recognition of brain signals and make it easier to provide. Post-processing changes the way detected brain signals are actually being used in an application. Although post- processing is standard practice with other inputs, this is not yet the case with BCIs. Of the more than 200 BCIs published about until 2006 only 15% used post-processing, according to an earlier literature study. A follow-up review shows that post-processing methods are still under-appreciated in BCI research, even though the improvements using these methods look very promising! To stimulate conscious use of and discussion about these post- processing methods, I provide a method overview with guidelines for appli- cation. At the same time, it is important to test these methods in practice. The goal of an experiment with eighteen participants was to reduce the nec- essary effort with post-processing. Although it did reduce the amount of active task execution time, this did not result in the expected reduction in perceived effort. Switching between the active and passive tasks cost more effort. \ud This work confirms the importance of good control to the user and offers BCI researchers and developers a solution: post-processing. An overview and guidelines are provided to stimulate deliberate use and discussion. The research also shows how essential user tests are

How much control is enough? Influence of unreliable input on user experience

Brain–computer interfaces (BCI) provide a valuable new input modality within human–computer interaction systems. However, like other body-based inputs such as gesture or gaze based systems, the system recognition of input commands is still far from perfect. This raises important questions, such as what level of control should such an interface be able to provide. What is the relationship between actual and perceived control? And in the case of applications for entertainment in which fun is an important part of user experience, should we even aim for the highest level of control, or is the optimum elsewhere? In this paper, we evaluate whether we can modulate the amount of control and if a game can be fun with less than perfect control. In the experiment users (n = 158) played a simple game in which a hamster has to be guided to the exit of a maze. The amount of control the user has over the hamster is varied. The variation of control through confusion matrices makes it possible to simulate the experience of using a BCI, while using the traditional keyboard for input. After each session the user completed a short questionnaire on user experience and perceived control. Analysis of the data showed that the perceived control of the user could largely be explained by the amount of control in the respective session. As expected, user frustration decreases with increasing control. Moreover, the results indicate that the relation between fun and control is not linear. Although at lower levels of control fun does increase with improved control, the level of fun drops just before perfect control is reached (with an optimum around 96%). This poses new insights for developers of games who want to incorporate some form of BCI or other modality with unreliable input in their game: for creating a fun game, unreliable input can be used to create a challenge for the user

Bacteria Hunt: A multimodal, multiparadigm BCI game

Brain-Computer Interfaces (BCIs) allow users to control applications by brain activity. Among their possible applications for non-disabled people, games are promising candidates. BCIs can enrich game play by the mental and affective state information they contain. During the eNTERFACE'09 workshop we developed the Bacteria Hunt game which can be played by keyboard and BCI, using SSVEP and relative alpha power. We conducted experiments in order to investigate what difference positive vs. negative neurofeedback would have on subjects' relaxation states and how well the different BCI paradigms can be used together. We observed no significant difference in mean alpha band power, thus relaxation, and in user experience between the games applying positive and negative feedback. We also found that alpha power before SSVEP stimulation was significantly higher than alpha power during SSVEP stimulation indicating that there is some interference between the two BCI paradigms

XoSoft connected monitor (XCM) unsupervised monitoring and feedback in soft exoskeletons of 3D kinematics, kinetics, behavioral context and control system status

Intelligent soft exoskeletons are developed to be used unsupervised and continuously on a large scale in normal daily situations. As they miss the stiffness of the structural components of traditional robotic devices, traditional robotic movement assessment are rendered useless, as they assume structural segment rigidity. This all requires a radical different approach towards (remote) monitoring and feedback of data relevant to a host of different type users: clinicians and therapists responsible for training and well-being of patient, caregivers, maintenance technicians and even the exoskeleton’s control system. This paper proposes such a system, one implementation of which is developed and tested within the XoSoft soft exoskeleton project. It provides continuous remote (partly IMMU based) assessment of 3D kinematics and kinetics, control system activity, subject activity pattern and derived movement pattern parameters. It also is structured in a maximally flexible way facilitating the ever-shifting, optimal distribution of functional software modules over more peripheral and central hardware to accommodate for fast changes in specifications and technical and practical constraints