Comparison of eye tracking, electrooculography and an auditory brain-computer interface for binary communication: a case study with a participant in the locked-in state.
BACKGROUND
In this study, we evaluated electrooculography (EOG), an eye tracker and an auditory brain-computer interface (BCI) as access methods to augmentative and alternative communication (AAC). The participant of the study has been in the locked-in state (LIS) for 6 years due to amyotrophic lateral sclerosis. He was able to communicate with slow residual eye movements, but had no means of partner independent communication. We discuss the usability of all tested access methods and the prospects of using BCIs as an assistive technology.


METHODS
Within four days, we tested whether EOG, eye tracking and a BCI would allow the participant in LIS to make simple selections. We optimized the parameters in an iterative procedure for all systems.


RESULTS
The participant was able to gain control over all three systems. Nonetheless, due to the level of proficiency previously achieved with his low-tech AAC method, he did not consider using any of the tested systems as an additional communication channel. However, he would consider using the BCI once control over his eye muscles would no longer be possible. He rated the ease of use of the BCI as the highest among the tested systems, because no precise eye movements were required; but also as the most tiring, due to the high level of attention needed to operate the BCI.


CONCLUSIONS
In this case study, the partner based communication was possible due to the good care provided and the proficiency achieved by the interlocutors. To ease the transition from a low-tech AAC method to a BCI once control over all muscles is lost, it must be simple to operate. For persons, who rely on AAC and are affected by a progressive neuromuscular disease, we argue that a complementary approach, combining BCIs and standard assistive technology, can prove valuable to achieve partner independent communication and ease the transition to a purely BCI based approach. Finally, we provide further evidence for the importance of a user-centered approach in the design of new assistive devices.
Institute of Psychology, University of Würzburg, Marcusstr. 9-11, 97070, Würzburg, Germany. ivo.kaethner@uni-wuerzburg.de.
Ivo
I
Käthner
Institute of Psychology, University of Würzburg, Marcusstr. 9-11, 97070, Würzburg, Germany. andrea.kuebler@uni-wuerzburg.de.
Andrea
A
Kübler
Institute of Psychology, University of Würzburg, Marcusstr. 9-11, 97070, Würzburg, Germany. sebastian.halder@uni-wuerzburg.de.|Department of Rehabilitation for Brain Functions, Research Institute of National Rehabilitation Center for Persons with Disabilities, 4-1 Namiki, Tokorozawa, Saitama, 359-8555, Japan. sebastian.halder@uni-wuerzburg.de.
Sebastian
S
Halder
D000690:Amyotrophic Lateral Sclerosis / Q000534:rehabilitation; D062207:Brain-Computer Interfaces; D017028:Caregivers / Q000523:psychology; D003143:Communication Devices for People with Disabilities; D004567:Electrodes, Implanted; D004569:Electroencephalography; D004585:Electrooculography / Q000379:methods*; D005133:Eye Movements / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009801:Oculomotor Muscles / Q000502:physiology; D017060:Patient Satisfaction; D011597:Psychomotor Performance / Q000502:physiology*; D011782:Quadriplegia / Q000523:psychology / Q000534:rehabilitation*; D012656:Self-Help Devices