Validation norms for speech discrimination scores of normal hearing subjects in wide band and in speech spectrum noise at speech to noise ratio of zero decibels
Doyle, K.J.; Rupp, R.R.
Journal of Auditory Research 17(4): 269-274
W-22 lists were given to 40 dB with a Maico MA-24B audiometer and attachments to 20 normal-hearing adults in quiet and in combination with either wide-band or speech-spectrum noise at S/N [signal to noise ratio] = 0, monaurally by earphone and binaurally by loudspeaker(s). No systematic L-R [left to right] differences were observed. DS [speech discrimination score] in quiet by any condition was at or near 100%. Mean DS in noise by monaural earphone was 79.80 .+-. 13.3 for wide-band noise and 54.7 .+-. 12.7 for speech-spectrum noise. When speech and noise were from 2 different loudspeakers placed .+-. 45.degree. from midline, DS was 90.8 .+-. 9.5 for wide-band noise and 88.1 .+-. 7.8 for speech-spectrum noise. When both speech and noise came from the same loudspeaker, DS was 79.10 .+-. 10.3 for wide-band noise and 57.0 .+-. 21.8 for speech-spectrum noise. These values are proposed as provisional norms for clinical facilities using these conditions and employing similar instrumentation.