Application of event related brain potentials to communication aids

This paper gives a brief explanation of event related brain potentials (ERPs) within an electroencephalogram (EEG) and discusses a method for their clear detection. An ERP is evoked as an inner psychological response to an outward physical stimulus. Basically, one is able to know when another person has a greater interest in one of various targets by detecting the ERP. The ERP appears from about 100 to 600 ms after the stimulating impulse. Unfortunately, the ERP is so weak as to be buried under the EEG. To detect the ERP, EEG records are transformed into a Haar-wavelet series, and accumulated over every stimulus. If one can characterize visual stimuli by any feature and arrange them in a semantic order, one is able to understand what a companion thinks. This means that one can have some conversation with a serious amyotrophic lateral sclerosis patient via a series of questions and answers.