Basic Research for Development of a Communication Support Device Using Air-Conducted Sound Localization

We have been engaged in the development of a new support device for subjects whose independent daily activities are limited due to severe progressive neuromuscular disease. In this study, we examined the possibility of developing a P300-type BCI (brain–computer interface) using orientation discrimination of stimulus sound with auditory lateralisation using a virtual sound source for air-conducted sound presented to the subject bitemporally. Sound stimulation with sound localization used in the study had a level difference of approximately 10 dB and time difference of approximately 0.6 ms, and was fixed at 60° to the left and to the right from the median. It was suggested that a virtual sound source with sound image fixed in left and right directions with added difference between the left and right ears can be used for development of a P300-type BCI by applying auditory stimulation. To further proceed to the development of a P300-type BCI system using auditory stimulation with comfort and convenience with the aim of reducing user burden in a clinical setting, we will reexamine the extraction algorithm for the target waveform, and examine the effects of the interval between stimulus presentation to make this a daily life supporting system to realise a faster and more efficient multiple command sending mechanism