ISO 8253-3:2012 音響学—聴力検査法—パート3：音声聴力検査 | ページ 6

3.1

speech signal

acoustic signal which carries information in a given language

Note 1 to entry: A speech signal may be a voice signal or an acoustic signal simulating a voice signal.

3.2

test item

particular monosyllabic or polysyllabic word or logatom, or sentence, or time-limited segment of connected speech, used in accordance with defined rules of presentation and scoring in a speech audiometric procedure

Note 1 to entry: Scoring may be based on a complete test item or parts thereof being correctly recognized.

3.3

speech material

entire set of test items which is used for speech recognition tests

Note 1 to entry: Usually the speech material is subdivided into several test lists.

3.4

open-set test material

set of test items in which the number of alternative responses to each test item is unlimited

3.5

closed-set test material

set of test items in which the number of alternative responses to each test item is limited

3.6

phoneme

smallest recognizable unit of speech in a given natural language

3.7

phoneme class

subdivision of phonemes that show characteristic similarities in vocal production mode as well as in acoustical signal properties

3.8

syllable

segment of speech which consists of a vowel with or without one or more accompanying consonants immediately preceding or following

3.9

spondee

two-syllable word with equal stress on each syllable

3.10

logatom

syllabic unit that has no verbal meaning to the listener

Note 1 to entry: A logatom is sometimes called a “nonsense syllable”.

3.11

test list

number of selected test items, presented and scored as a single unit

3.12

set of test items

selected number of test items from a test list

3.13

phonemically balanced test list

test list which contains approximately the same proportions of the various phonemes as are present in typical speech communication within a given language

3.14

perceptually balanced test list

test list which yield equivalent speech recognition score with minimized variance at a specified speech level under equivalent conditions (specified manner of presentation and specified group of listeners)

Note 1 to entry: Usually the specified group of listeners consists of otologically normal persons with an age from 18 years to 25 years inclusive. For special tests, different groups (e.g. otologically normal children within a specified age range) may be used as well.

3.15

carrier phrase

sentence or phrase in which a test item is embedded such that the correct recognition of the test item is not dependent upon the context or meaning of the sentence or phrase

3.16

reference recording of speech material

master recording

well-defined recording that represents the speech material and that is used for validation and application of the speech material

3.17

speech level

equivalent continuous sound pressure level of the speech material as measured in an appropriate coupler, ear simulator or in a sound field, with frequency weighting C according to IEC 61672-1

Note 1 to entry: For speech test lists based on single test items separated by silent intervals, the integration does not include these intervals. For test lists based on single test items with a carrier phrase, the integration includes the test items only. In a digital recording, the silent intervals can be removed by editing. Numerical correction may also be made by determination of the total duration of the test items and the total duration of the silent intervals.

3.18

equivalent continuous sound pressure level

L_{p ,eq T}

Note 1 to entry: Because of practical limitations of the measuring instruments, p² is always understood to denote the square of a frequency-weighted and frequency-band-limited sound pressure. If a specific frequency weighting as specified in IEC 61672-1 and/or specific frequency bands are applied, this should be indicated by appropriate subscripts; e.g. L_{p ,A,10 s} denotes the A-weighted time-averaged sound pressure level over 10 s.

[SOURCE: ISO/TR 25417 ^[3] , 2.3]

3.19

speech detection threshold level

for a given test subject, for specified speech material and a specified manner of signal presentation, the speech level at which it is detected (not necessarily understood) in 50 % of the trials

3.20

speech recognition score

for a given test subject, for specified speech material, a specified manner of signal presentation and at a specified speech level, the percentage of correctly recognized test items or scorable items if the scoring method is not based on whole test items

3.21

maximum speech recognition score

for a given test subject, for specified speech material and a specified manner of signal presentation, the maximum speech recognition score obtained regardless of speech level

3.22

speech recognition threshold level

for a given test subject, for specified speech material and a specified manner of signal presentation, the lowest speech level or speech-to-noise ratio at which the speech recognition score is equal to 50 %

Note 1 to entry: Speech recognition threshold has been called “speech reception threshold”.

3.23

reference speech recognition threshold level

for specified speech material and a specified manner of signal presentation, the median value of the speech recognition threshold levels of a sufficiently large number of otologically normal persons, of both sexes, between 18 years and 25 years inclusive for whom the test material is appropriate

3.24

optimum speech level

for a given test subject, for specified speech material and a specified manner of signal presentation, the speech level or range of speech levels at which maximum speech recognition score is obtained

3.25

half-optimum speech level

for a given test subject, for specified speech material and a specified manner of signal presentation, the speech level at which half of the maximum speech recognition score is obtained

3.26

speech recognition curve

for a given test subject, for specified speech material and a specified manner of signal presentation, a curve that describes the speech recognition score as a function of speech level

3.27

reference speech recognition curve

for specified speech material and a specified manner of presentation, a curve that describes the median speech recognition score as a function of speech level for a sufficiently large number of otologically normal persons of both sexes, aged between 18 years and 25 years inclusive and for whom the test material is appropriate

3.28

hearing level for speech

for specified speech material and a specified manner of signal presentation, the speech level minus the appropriate reference speech recognition threshold level

3.29

competing sound

additional sound that is presented during speech recognition tests

3.30

competing sound pressure level

equivalent continuous sound pressure level of a competing sound as measured in an appropriate coupler, ear simulator or in a sound field, with frequency weighting C according to IEC 61672-1

3.31

speech-to-noise level difference

speech-to-noise ratio

SNR

difference between the speech level and the competing sound level

3.32

effective masking level for speech

level of a specified masking sound which is numerically equal to that hearing level for speech to which the speech recognition threshold level for a specified speech signal would be raised by the presence of that masking sound

3.33

most comfortable level for speech

for a given test subject and a specified manner of presentation, the speech level at which the loudness of the speech signal is judged by the test subject to be the most comfortable

3.34

connected speech

running speech

continuous speech with natural intonation, consisting of consecutive sentences with logical connections