Patent ID: 9479880
Filing Date: 2016-10-25
CPC Classification: A61B,H04R

Claim Text:
1. A speech discrimination ability determination system comprising: a biological signal measurement section that measures an electroencephalogram signal of a user; a sound stimulation determination section that determines, by referring to a speech sound database storing information of a plurality of speech sounds, a first speech sound and a second speech sound which are different from each other; an output section that switches between: a first trial in which the first speech sound is output with a first occurrence frequency and the second speech sound is output with a second occurrence frequency different from the first occurrence frequency; and a second trial in which the first speech sound is output with the second occurrence frequency and the second speech sound is output with the first occurrence frequency; an event-related potential acquisition section that acquires an event-related potential contained in the electroencephalogram signal, the event-related potential acquisition section acquiring: an event-related potential based on a point of outputting the first speech sound being output with the first occurrence frequency as a starting point; an event-related potential based on a point of outputting the first speech sound being output with the second occurrence frequency as a starting point; an event-related potential based on a point of outputting the second speech sound being output with the first occurrence frequency as a starting point; and an event-related potential based on a point of outputting the second speech sound being output with the second occurrence frequency as a starting point; an MMN determination section that acquires, with respect to each of the first speech sound and the second speech sound, difference information between the event-related potential acquired during its output with the first occurrence frequency and the event-related potential acquired during its output with the second occurrence frequency, and configured to determine whether a negative component exists in the difference information in predetermined time ranges after the first speech sound and the second speech sound are output; and a discrimination ability determination section that determines that the user discriminates the first speech sound and the second speech sound when a determination result by the MMN determination section indicates that the negative component exists; wherein the output section outputs the first speech sound and the second speech sound with the first occurrence frequency being X (0<X<0.5) and the second occurrence frequency being (1−X).