[Speech audiometry using the American Word Lists for Japanese subjects with normal hearing]

The characteristics of listening to English words for Japanese people were studied in ten normal hearing subjects who had taken English classes to the level of college graduates and had opportunities to learn English continuously. Following pure tone audiometry, speech audiometry was performed using the Central Institute for the Deaf (CID) W-1 and W-22 word lists for English and the 67-S word lists for Japanese. The speech reception thresholds (SRTs) for the CID W-1 lists were significantly higher than average pure tone threshold (PTT), although the SRTs for the 67-S lists were equal to the average PTT. The difference in average SRT between the CID W-1 lists and the 67-S lists was about 15dB, which is statistically significant. The speech discrimination rate for the CID W-22 lists ranged from 78 to 100 percent with an average of 89.5 percent, while all subjects achieved the discrimination rate of 100 percent for the 67-S lists. Analysis with transient matrices of the perceived words demonstrated that the articulation rates were below 90 percent for the consonants /m/, /n/, /p/ and /delta/ . The observed variation in the speech discrimination score and the pattern of confusion among the subjects was assumed to be much more pronounced in noisy conditions.