According to a conventional BMI technology for controlling external equipment or transmitting an intention to another person by focusing on a biosignal such as brain activity, there has been the problem that a large-sized apparatus is required, the operation method is complex from the user's viewpoint, and noise is large. The present invention provides an apparatus and method such that an intention in the brain can be analyzed with high accuracy and at high speed and transmitted in real-time. A communication assist apparatus according to the present invention comprises an apparatus for presenting a visual stimulus on a display screen and the like, and a processing apparatus for processing brain wave data from an electroencephalograph that measures a brain wave after stimulus presentation by the presenting apparatus. The processing apparatus determines that a specific intention decision has been made in the brain when the product of an accumulated discrimination score according to a discriminant analysis function obtained by analyzing the brain wave data and a success rate exceeds a threshold value, and then outputs a determination result to a device.
