Assessment system of speech sound listening, and method and program thereof

1. An assessment system of speech sound listening, comprising:

a biological signal measurement unit configured to measure an electroencephalogram signal of a user;

a presented-speech sound determination unit configured to determine a monosyllabic speech sound to be presented, by referring to a speech sound database retaining a plurality of monosyllabic speech sounds;

an output unit configured to present a speech sound determined by the presented-speech sound determination unit to the user as an auditory stimulation;

a positive component determination unit configured to determine a strife parameter concerning how much effort has been made to aurally distinguish the speech sound based on whether a positive component appears in an event-related potential of the electroencephalogram signal in a range from 600 ms to 900 ms from a starting point, the starting point being a point in time at which the speech sound is presented, and configured to output an assessment result as to whether the user is listening to the speech sound with strife or not in accordance with a result of determination; and

a negative component determination unit configured to determine an annoyance parameter indicating how annoying by loudness the speech sound has been felt based on whether a negative component appears in an event-related potential of the electroencephalogram signal in a range from 100 ms to 300 ms from a starting point, the starting point being the point in time at which the speech sound is presented, and configured to output an assessment result as to whether the user is annoyed by loudness of the speech sound or not in accordance with a result of determination.

2. The assessment system of speech sound listening of claim 1 , further comprising an event-related potential processing unit configured to take an arithmetic mean of event-related potentials of the electroencephalogram signal, wherein the speech sound is classified based on at least one of a speech sound type and a sound pressure level of presentation, and the event-related potential processing unit takes an arithmetic mean of event-related potentials of the electroencephalogram signals obtained when speech sounds belonging to a same classification are presented.

3. The assessment system of speech sound listening of claim 1 , wherein the positive component determination unit determines that the positive component is present when a zone average potential of an event-related potentials of the electroencephalogram signals in a range from 600 ms to 900 ms from a starting point, the starting point being a point in time at which the speech sound is presented, is equal to or greater than a predetermined first threshold value, and determines that the positive component is absent when the zone average potential is smaller than the first threshold value.

4. The assessment system of speech sound listening of claim 3 , wherein the positive component determination unit outputs an assessment result that the user is listening to the speech sound with strife when determining that the positive component is present, and outputs an assessment result that the user is hearing the speech sound without strife when determining that the positive component is absent.

5. The assessment system of speech sound listening of claim 1 , wherein the negative component determination unit determines that the negative component is present when a peak latency of a negative component in a range from 100 ms to 300 ms from a starting point, the starting point being a point in time at which the speech sound is presented, is shorter than a predetermined second threshold value, and determines that the negative component is absent when the peak latency of the negative component is equal to or greater than the second threshold value.

6. The assessment system of speech sound listening of claim 5 , wherein the negative component determination unit outputs an assessment result that the user is annoyed by the speech sound when determining that the negative component is present, and outputs an assessment result that the user is not annoyed by the speech sound when determining that the negative component is absent.

7. The assessment system of speech sound listening of claim 5 , wherein, in the speech sound database, an audio, consonant information, and a group concerning probability of confusion are associated with each of the plurality of speech sounds.

8. The assessment system of speech sound listening of claim 7 , further comprising a result accumulating database configured to accumulate results of determination by the positive component determination unit and the negative component determination unit, wherein

with respect to at least one sound pressure level, the result accumulating database calculates a proportion of speech sounds, consonants, or groups concerning probability of confusion for which the positive component determination unit has determined that the positive component is absent, and a proportion of speech sounds, consonants, or groups concerning probability of confusion for which the negative component determination unit has determined that the negative component is absent, and generates assessment results by using results of the calculation.

9. The assessment system of speech sound listening of claim 7 , wherein, in a result accumulating database, information for assessing whether the user is listening to the speech sound with strife and whether the user is annoyed by the speech sound is accumulated with respect to each speech sound, each consonant, or each group concerning probability of confusion.

10. The assessment system of speech sound listening of claim 9 , wherein, in the result accumulating database, information for assessing whether the user is listening to the speech sound with strife and whether the user is annoyed by the speech sound is accumulated with respect to each speech sound and each sound pressure level.

11. The assessment system of speech sound listening of claim 5 , wherein the presented-speech sound determination unit determines a sound pressure level of the presented audio.

12. The assessment system of speech sound listening of claim 5 , further comprising an acoustic aiding processing unit configured to select an acoustic aiding process type for the speech sound determined by the presented-speech sound determination unit for presentation, and configured to modify speech sound data retained in the speech sound database based on the selected acoustic aiding process.

13. The assessment system of speech sound listening of claim 12 , further comprising a result accumulating database configured to accumulate results of determination by the positive component determination unit and the negative component determination unit, wherein

in the result accumulating database, information for assessing whether the user is listening to the speech sound with strife and whether the user is annoyed by the speech sound is accumulated with respect to each speech sound and each acoustic aiding process.

14. An assessment apparatus of speech sound listening, comprising:

a presented-speech sound determination unit configured to, by referring to a speech sound database retaining a plurality of monosyllabic speech sounds, determine one of the monosyllabic speech sounds to be presented via an output unit to a user as an auditory stimulation;

a positive component determination unit configured to, with respect to an electroencephalogram signal measured by a biological signal measurement unit for measuring an electroencephalogram signal of the user, determine a strife parameter concerning how much effort has been made to aurally distinguish the speech sound based on whether a positive component appears in an event-related potential of the electroencephalogram signal in a range from 600 ms to 900 ms from a starting point, the starting point being a point in time at which the speech sound is presented; and

a negative component determination unit configured to determine an annoyance parameter indicating how annoying by loudness the speech sound has been felt based on whether a negative component appears in an event-related potential of the electroencephalogram signal in a range from 100 ms to 300 ms from a starting point, the starting point being the point in time at which the speech sound is presented.

15. A assessment method of speech sound listening, comprising the steps of:

measuring an electroencephalogram signal of a user;

determining a monosyllabic speech sound to be presented, by referring to a speech sound database retaining a plurality of monosyllabic speech sounds;

presenting a speech sound determined by the step of determining to the user as an auditory stimulation;

determining a strife parameter concerning how much effort has been made to aurally distinguish the speech sound based on whether a positive component appears in an event-related potential of the electroencephalogram signal in a range from 600 ms to 900 ms from a starting point, the starting point being a point in time at which the speech sound is presented;

outputting an assessment result as to whether the user is listening to the speech sound with strife or not in accordance with a result of determination;

determining an annoyance parameter indicating how annoying by loudness the speech sound has been felt based on whether a negative component appears in an event-related potential of the electroencephalogram signal in a range from 100 ms to 300 ms from a starting point, the starting point being the point in time at which the speech sound is presented; and

outputting an assessment result as to whether the user is annoyed by loudness of the speech sound or not in accordance with a result of determination.

16. A non-transitory computer readable medium storing a computer program to be executed by a computer mounted in a speech sound intelligibility assessment system,

wherein the computer program causes the computer in the speech sound intelligibility assessment system to execute the steps of:

receiving a measured electroencephalogram signal of a user;

determining a monosyllabic speech sound to be presented, by referring to a speech sound database retaining a plurality of monosyllabic speech sounds;

presenting a speech sound determined by the step of determining to the user as an auditory stimulation;

determining a strife parameter concerning how much effort has been made to aurally distinguish the speech sound based on whether a positive component appears in an event-related potential of the electroencephalogram signal in a range from 600 ms to 900 ms from a starting point, the starting point being a point in time at which the speech sound is presented;

outputting an assessment result as to whether the user is listening to the speech sound with strife or not in accordance with a result of determination;

determining an annoyance parameter indicating how annoying by loudness the speech sound has been felt based on whether a negative component appears in an event-related potential of the electroencephalogram signal in a range from 100 ms to 300 ms from a starting point, the starting point being the point in time at which the speech sound is presented, and

outputting an assessment result as to whether the user is annoyed by loudness of the speech sound or not in accordance with a result of determination.