A Multifunctional Brain-Computer Interface Intended for Home Use: An Evaluation with Healthy Participants and Potential End Users with Dry and Gel-Based Electrodes

Abstract

Current brain-computer interface (BCIs) software is often tailored to the needs of scientists and technicians and therefore complex to allow for versatile use. To facilitate home use of BCIs a multifunctional P300 BCI with a graphical user interface intended for non-expert set-up and control was designed and implemented. The system includes applications for spelling, web access, entertainment, artistic expression and environmental control. In addition to new software, it also includes new hardware for the recording of electroencephalogram (EEG) signals. The EEG system consists of a small and wireless amplifier attached to a cap that can be equipped with gel-based or dry contact electrodes. The system was systematically evaluated with a healthy sample, and targeted end users of BCI technology, i.e., people with a varying degree of motor impairment tested the BCI in a series of individual case studies. Usability was assessed in terms of effectiveness, efficiency and satisfaction. Feedback of users was gathered with structured questionnaires. Two groups of healthy participants completed an experimental protocol with the gel-based and the dry contact electrodes (N = 10 each). The results demonstrated that all healthy participants gained control over the system and achieved satisfactory to high accuracies with both gel-based and dry electrodes (average error rates of 6 and 13%). Average satisfaction ratings were high, but certain aspects of the system such as the wearing comfort of the dry electrodes and design of the cap, and speed (in both groups) were criticized by some participants. Six potential end users tested the system during supervised sessions. The achieved accuracies varied greatly from no control to high control with accuracies comparable to that of healthy volunteers. Satisfaction ratings of the two end-users that gained control of the system were lower as compared to healthy participants. The advantages and disadvantages of the BCI and its applications are discussed and suggestions are presented for improvements to pave the way for user friendly BCIs intended to be used as assistive technology by persons with severe paralysis.

Neural mechanisms of training an auditory event‐related potential task in a brain–computer interface context

“…Affected individuals may overcome this communication impairment by using a brain–computer interface (BCI), usually controlled via electroencephalogram (EEG) components. Modern BCIs offer control over a variety of applications and can be used independently at home and may be used for mental state monitoring (Holz, Botrel, Kaufmann, & Kübler, ; Juel, Romundstad, Kolstad, Storm, & Larsson, ; Käthner et al, ).…”

Evaluation of EEG Headset Mounting for Brain-Computer Interface-Based Stroke Rehabilitation by Patients, Therapists, and Relatives

“…Then the patient is asked to perform several movements, 30-50 movements, to calibrate the classifier in the BCI system, and then the actual training starts where the BCI decodes the movement intention generated from the motor cortex and triggers the external device that provides feedback. Such BCI training has a beneficial effect on motor recovery (Cervera et al, 2018), but there are a number of pitfalls when using BCI technology outside the laboratory without a BCI expert/engineer (Leeb et al, 2013;Käthner et al, 2017). These include the complexity of the EEG headset setup (in terms of effort), robustness and performance of the BCI system, and system calibration before each use.…”

“…The therapist can then spend more time on other types of training and patients, or the patients could be training in their own home. Many of the caps currently commercially available may be difficult to mount by oneself since the electrodes must cover the motor cortex to record the electrical activity associated with attempted movements, and only a few comparisons between headsets or headset usability have been made (Ekandem et al, 2012;Mayaud et al, 2013;Das et al, 2014;Hairston et al, 2014;Nijboer et al, 2015;Halford et al, 2016;Izdebski et al, 2016;Pinegger et al, 2016;Käthner et al, 2017;Zander et al, 2017;Radüntz and Meffert, 2019). These studies relied on different metrics but often report on comfort and setup time.…”

“…Other aspects covered by them include the unobtrusiveness (Das et al, 2014) and design elements such as adaptability of head sizes, external trigger integration, cap fit, and variance in scalp electrode locations (Hairston et al, 2014;Izdebski et al, 2016). Moreover, the satisfaction using questionnaires and system preferences are reported as well (Hairston et al, 2014;Nijboer et al, 2015;Pinegger et al, 2016;Käthner et al, 2017). Another aspect to consider is the aesthetics of the headset, which has been reported to be important (Nijboer et al, 2014).…”

“…Another aspect to consider is the aesthetics of the headset, which has been reported to be important (Nijboer et al, 2014). Most evaluations of headsets and electrode types used healthy subjects, but a few included veterans and severely motor impaired patients (Halford et al, 2016;Käthner et al, 2017), caregivers (Käthner et al, 2017). Only in two studies, participants -healthy volunteers -mounted the headset themselves (Zander et al, 2017;Radüntz and Meffert, 2019).…”